Mechanics Quiz: Kinematics and Dynamics of Machines
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Questions and Answers

What is the degree of freedom of a sliding pair?

  • 6
  • 1 (correct)
  • 2
  • 3

    • What type of pair has a combination of turning and sliding motion?

  • Cylindrical pair (correct)
  • Helical pair
  • Spherical pair
  • Rolling pair

    • What is the degree of freedom of a spherical pair?

  • 3 (correct)
  • 1
  • 6
  • 2

    • What type of pair has a surface contact and three degrees of freedom?

    <p>Spherical pair</p> Signup and view all the answers

    What is the degree of freedom of a rolling pair?

    <p>1</p> Signup and view all the answers

    What type of pair has a turning motion of one element with respect to the other?

    <p>Turning pair</p> Signup and view all the answers

    What is a mechanism?

    <p>A kinematic chain with one link fixed</p> Signup and view all the answers

    What is the number of independent input parameters needed to determine the position of all the links of a mechanism?

    <p>Degrees of freedom</p> Signup and view all the answers

    What type of mechanism has all the links moving in planes parallel to the reference plane?

    <p>Planar mechanism</p> Signup and view all the answers

    What is a closed pair in mechanics?

    <p>Elements held together mechanically due to their geometry</p> Signup and view all the answers

    What is the branch of scientific analysis that deals with motion, time, and force?

    <p>Mechanics</p> Signup and view all the answers

    What is the study of motion, without considering the forces which produce that motion?

    <p>Kinematics</p> Signup and view all the answers

    What is the study of the relative motion of machine parts?

    <p>Kinematics of machines</p> Signup and view all the answers

    What is the study of forces acting on the machine parts and the motions resulting from these forces?

    <p>Dynamics of machines</p> Signup and view all the answers

    What type of motion does a body have, if all its points move in planes which are parallel to some reference plane?

    <p>Plane motion</p> Signup and view all the answers

    How many degrees of freedom does a body with plane motion have?

    <p>3</p> Signup and view all the answers

    What is a machine part or a component of a mechanism called?

    <p>Kinematic link</p> Signup and view all the answers

    What type of link is connected to other links at two points?

    <p>Binary link</p> Signup and view all the answers

    What is a rigid link in a machine?

    <p>A link that does not undergo any deformation while transmitting motion</p> Signup and view all the answers

    What is the primary function of a fluid link in a machine?

    <p>To transmit force through pressure or compression</p> Signup and view all the answers

    What is the key characteristic of a machine?

    <p>It transforms energy into useful work</p> Signup and view all the answers

    What is the primary difference between a machine and a structure?

    <p>A machine has relative motion between its parts, while a structure does not</p> Signup and view all the answers

    What is a kinematic pair?

    <p>Two links or elements of a machine that are in contact with each other</p> Signup and view all the answers

    What is a lower pair in a kinematic pair?

    <p>A pair that has surface contact between the elements</p> Signup and view all the answers

    What is the primary difference between a mechanism and a machine?

    <p>A mechanism modifies and transmits motion, while a machine transforms energy</p> Signup and view all the answers

    What is the primary function of a structure?

    <p>To carry loads having straining action</p> Signup and view all the answers

    What is the primary difference between a machine and a mechanism?

    <p>A machine transforms energy into useful work, while a mechanism modifies and transmits motion</p> Signup and view all the answers

    What is the field of study that deals with structures?

    <p>Statics</p> Signup and view all the answers

    What is the formula for the Kutzbach criterion for the mobility of a planar mechanism?

    <p>n = 3(l-1) + h</p> Signup and view all the answers

    What is the term for fixing different links of the same kinematic chain to obtain different mechanisms?

    <p>Inversion of mechanism</p> Signup and view all the answers

    Which link in a four-bar linkage makes complete rotation?

    <p>Link 2</p> Signup and view all the answers

    What is the term for the link connecting the driving crank with the follower crank in a four-bar linkage?

    <p>Coupler</p> Signup and view all the answers

    What is the purpose of quick return motion mechanisms?

    <p>To give the reciprocating cutting tool a slow cutting stroke and a quick return stroke</p> Signup and view all the answers

    Which mechanism is used to convert rotary motion to reciprocating motion and vice versa?

    <p>Slider crank chain</p> Signup and view all the answers

    What is the type of mechanism where links 1 and 3 are equal and parallel and links 2 and 4 are equal and parallel?

    <p>Double crank mechanism</p> Signup and view all the answers

    What is the term for the path generated by a point attached to the coupler during the motion of the mechanism?

    <p>Coupler curve</p> Signup and view all the answers

    What is the mechanism used in shaping and slotting machines?

    <p>Whitworth quick return motion mechanism</p> Signup and view all the answers

    What is the term for the link that oscillates in a four-bar linkage?

    <p>Rocker</p> Signup and view all the answers

    What is the direction of the motion of the tool in a quick return motion mechanism?

    <p>Along the line RD produced</p> Signup and view all the answers

    What is the ratio of the time taken during the cutting and return strokes in a quick return motion mechanism?

    <p>ß:a</p> Signup and view all the answers

    What is the purpose of the short link PR in a quick return motion mechanism?

    <p>To transmit the motion from AP to the ram</p> Signup and view all the answers

    What type of motion does the crank CB have in a quick return motion mechanism?

    <p>Uniform angular velocity</p> Signup and view all the answers

    What is the name of the mechanism where the cylinder or link 4 is fixed?

    <p>Pendulum pump or bull engine</p> Signup and view all the answers

    What is the study of relative motion between the various parts of the machines?

    <p>Kinematics</p> Signup and view all the answers

    What is the purpose of velocity analysis in mechanisms?

    <p>To determine the acceleration of points in the mechanisms</p> Signup and view all the answers

    What type of motion does the piston rod have in a pendulum pump or bull engine?

    <p>Reciprocating motion</p> Signup and view all the answers

    What is the direction of the stroke of the ram in a quick return motion mechanism?

    <p>Perpendicular to the line AC</p> Signup and view all the answers

    What is the name of the mechanism used in shaping machines, slotting machines, and rotary internal combustion engines?

    <p>Crank and slotted lever quick return motion mechanism</p> Signup and view all the answers

    What is kinematic synthesis?

    <p>The creation of something new to achieve a desired performance</p> Signup and view all the answers

    What are the basic building blocks of all mechanisms?

    <p>Linkages</p> Signup and view all the answers

    What is a joint in a mechanism?

    <p>A connection between two or more links</p> Signup and view all the answers

    How can joints be classified?

    <p>By all of the above methods</p> Signup and view all the answers

    What is a link in a mechanism?

    <p>A rigid member having nodes</p> Signup and view all the answers

    What is a node in a mechanism?

    <p>An attachment point on a link</p> Signup and view all the answers

    What is the primary function of kinematic synthesis?

    <p>To achieve a desired performance in a mechanical system</p> Signup and view all the answers

    What is the result of kinematic synthesis?

    <p>The design of a mechanism that achieves a desired performance</p> Signup and view all the answers

    What is the D'Alembert's principle?

    <p>A principle that states the reverse-effective forces and torques and the external forces and torques on a body together give statical equilibrium.</p> Signup and view all the answers

    What is the reverse-effective force?

    <p>A force that is proportional to the mass of the body and its acceleration.</p> Signup and view all the answers

    What is the inertia torque or inertia couple?

    <p>A pure torque or couple.</p> Signup and view all the answers

    What is the general moment summation about an arbitrary point P?

    <p>?TP = ?TeP + Ci + RPG × Ft</p> Signup and view all the answers

    What is the equivalent offset inertia force?

    <p>A single force that accounts for both translational inertia and rotational inertia corresponding to the plane motion of a rigid body.</p> Signup and view all the answers

    What is the dynamic analysis problem reduced to?

    <p>A static force and moment balance where inertia effects are treated in the same manner as external forces and torques.</p> Signup and view all the answers

    What is the significance of D'Alembert's principle?

    <p>It reduces the dynamic analysis problem to a static force and moment balance.</p> Signup and view all the answers

    What is the relationship between the inertia force and the mass of the body?

    <p>The inertia force is directly proportional to the mass of the body.</p> Signup and view all the answers

    What is the significance of the equivalent offset inertia force?

    <p>It facilitates graphical plane force analysis.</p> Signup and view all the answers

    What is the direction of the inertia force?

    <p>It acts through the center of mass G of the body.</p> Signup and view all the answers

    What is the sense of the couple in the figure C?

    <p>Clockwise</p> Signup and view all the answers

    What is the magnitude of the equivalent offset force?

    <p>|maG|</p> Signup and view all the answers

    What is the direction of the equivalent offset force?

    <p>Opposite to the acceleration</p> Signup and view all the answers

    What is the purpose of graphical force analysis?

    <p>To demonstrate the usefulness of the approach</p> Signup and view all the answers

    What is the type of mechanism shown in the schematic diagram?

    <p>Slider-crank mechanism</p> Signup and view all the answers

    What is the purpose of a free body diagram?

    <p>To solve static and dynamic problems</p> Signup and view all the answers

    What are the forces acting on a book on a table?

    <p>Weight W and normal force N</p> Signup and view all the answers

    What are the forces acting on a suspended block at rest?

    <p>Weight W and tension force T</p> Signup and view all the answers

    What are the forces acting on a block on a floor with an acting force Fa?

    <p>Weight W, normal force N, acting force Fa, and friction force Ff</p> Signup and view all the answers

    What is the primary function of a dynamic analysis?

    <p>To understand the relationships of the inertia forces and torques</p> Signup and view all the answers

    What is the definition of inertia force according to D'Alembert's principle?

    <p>Fi = -maG</p> Signup and view all the answers

    What is the purpose of D'Alembert's principle in dynamic force analysis?

    <p>To reduce the dynamic analysis problem to a static force and moment balance</p> Signup and view all the answers

    What is the equation for the moment summation about an arbitrary point P in a body?

    <p>TP = TeP + Ci + RPG × Ft</p> Signup and view all the answers

    What is the equivalent offset inertia force used for?

    <p>For graphical plane force analysis</p> Signup and view all the answers

    What is the expression for the inertia torque Ci?

    <p>Ci = -IGa</p> Signup and view all the answers

    What is the significance of the vector RPG in the moment summation equation?

    <p>It is the position vector from point P to point C</p> Signup and view all the answers

    What is the condition for the couple to be equivalent to the inertia torque?

    <p>The sense and magnitude must be the same</p> Signup and view all the answers

    What is the purpose of d'Alembert's principle in treating inertia effects?

    <p>To treat inertia effects as external forces and torques</p> Signup and view all the answers

    What is the relationship between the external forces and moments and the inertia forces and couples?

    <p>They are additive</p> Signup and view all the answers

    What is the significance of the joint order in a mechanism?

    <p>It is equal to the number of links - 1</p> Signup and view all the answers

    What is the primary purpose of kinematic synthesis in machine design?

    <p>To create a desired performance by combining parts to form a whole</p> Signup and view all the answers

    What is the fundamental component of all mechanisms?

    <p>Linkages</p> Signup and view all the answers

    What is a joint in a mechanism?

    <p>A connection between two or more links allowing motion</p> Signup and view all the answers

    What is the term for the attachment points of a link in a mechanism?

    <p>Nodes</p> Signup and view all the answers

    What is the classification of joints based on the number of degrees of freedom they allow?

    <p>By the number of degrees of freedom allowed</p> Signup and view all the answers

    What is the purpose of designing mechanisms in machines?

    <p>To achieve required output forces and movement for a given input</p> Signup and view all the answers

    What is a link in a mechanism?

    <p>A rigid member with nodes</p> Signup and view all the answers

    What is the process of converting a motion idea into hardware?

    <p>Kinematic synthesis</p> Signup and view all the answers

    What is the direction of the single equivalent offset force?

    <p>Opposite to the direction of acceleration a</p> Signup and view all the answers

    What is the magnitude of the single equivalent offset force?

    <p>| maG |</p> Signup and view all the answers

    What is the purpose of graphical force analysis?

    <p>To determine the dynamic forces in a system</p> Signup and view all the answers

    What is the relationship between the couple and the sense of rotation?

    <p>The couple must be clockwise and the sense of rotation must be clockwise</p> Signup and view all the answers

    What is the purpose of a free body diagram?

    <p>To understand and solve static and dynamic problems involving forces</p> Signup and view all the answers

    What is the number of forces acting on the block in the example of a block on a floor with an acting force Fa to pull the block?

    <p>4</p> Signup and view all the answers

    What is the primary function of dynamic analysis in the design of slider crank mechanisms?

    <p>To consider the dynamic forces in the design</p> Signup and view all the answers

    What is the purpose of converting inertia forces and torques to equivalent offset forces?

    <p>To simplify the graphical analysis</p> Signup and view all the answers

    What is the advantage of using the approach of including the original inertia force and inertia torque?

    <p>It is usually unnecessary in analytical solutions</p> Signup and view all the answers

    What is the purpose of the analysis of a four-bar linkage?

    <p>To illustrate most of the ideas presented in dynamic analysis</p> Signup and view all the answers

    What is the primary goal of kinematic synthesis in machine design?

    <p>To achieve a desired performance by converting a motion idea into hardware</p> Signup and view all the answers

    What is the fundamental component of all mechanisms?

    <p>Linkages</p> Signup and view all the answers

    What is a joint in a mechanical system?

    <p>A connection between two or more links that allows motion</p> Signup and view all the answers

    How can joints be classified?

    <p>By the number of degrees of freedom allowed</p> Signup and view all the answers

    What is the term for a link with three nodes?

    <p>Ternary link</p> Signup and view all the answers

    What is the purpose of kinematic synthesis in machine design?

    <p>To convert a motion idea into hardware</p> Signup and view all the answers

    What is the term for a rigid member with nodes?

    <p>Link</p> Signup and view all the answers

    What is the result of kinematic synthesis in machine design?

    <p>A machine that achieves a desired performance</p> Signup and view all the answers

    What is the condition for the couple to be arbitrary and have an infinite number of possibilities?

    <p>There are no conditions for the couple to be arbitrary</p> Signup and view all the answers

    What is the magnitude of the equivalent offset force in Figure C?

    <p>|maG|</p> Signup and view all the answers

    What is the significance of d'Alembert's principle in dynamic force analysis?

    <p>It is a principle that states the sum of external forces and inertia forces is equal to zero</p> Signup and view all the answers

    What is the expression for the inertia force in a rigid body?

    <p>Fi = -maG</p> Signup and view all the answers

    What is the direction of the equivalent offset force in Figure C?

    <p>Opposite to the direction of acceleration a</p> Signup and view all the answers

    What is the purpose of including the original inertia force and inertia torque in the analysis?

    <p>To apply the approach directly</p> Signup and view all the answers

    What is the purpose of the equivalent offset inertia force in graphical plane force analysis?

    <p>To account for both translational and rotational inertia</p> Signup and view all the answers

    What is the advantage of the approach of converting inertia forces and torques to equivalent offset forces?

    <p>It is more useful for graphical force analysis</p> Signup and view all the answers

    What is the expression for the dynamic moment equilibrium about an arbitrary point P in a rigid body?

    <p>?TP = ?TeP + Ci + RPG × Ft</p> Signup and view all the answers

    What is the significance of the inertia torque in a rigid body?

    <p>It is a measure of the rotational inertia of the body</p> Signup and view all the answers

    What is the purpose of the free body diagram in mechanics?

    <p>To understand and solve static and dynamic problems involving forces</p> Signup and view all the answers

    What are the necessary steps to draw a free body diagram?

    <p>First, understand all the forces acting on the object, and then represent these forces by arrows in the direction of the force</p> Signup and view all the answers

    What is the direction of the inertia force in a rigid body?

    <p>It is in the opposite direction of the acceleration of the body</p> Signup and view all the answers

    What is the expression for the moment summation about the center of mass G in a rigid body?

    <p>?TG = ?TeG + Ci</p> Signup and view all the answers

    What is the purpose of the dynamic analysis of a four-bar linkage?

    <p>To demonstrate the ideas presented in the text</p> Signup and view all the answers

    What is the purpose of the dynamic analysis of a slider-crank mechanism?

    <p>To consider the relationships of the inertia forces and torques to the bearing reactions and the drive torque</p> Signup and view all the answers

    What is the significance of the dynamic force analysis in a rigid body?

    <p>It is used to analyze the dynamic forces acting on the body</p> Signup and view all the answers

    What is the purpose of the kinematics analysis of a slider-crank mechanism?

    <p>To develop expressions for the inertia force and inertia torque for each of the moving members</p> Signup and view all the answers

    What is the expression for the inertia couple in a rigid body?

    <p>Ci = -IGa</p> Signup and view all the answers

    What is the significance of the equivalent offset inertia force in a rigid body?

    <p>It is used to simplify the graphical plane force analysis</p> Signup and view all the answers

    What is the purpose of the cam in a cam-follower pair?

    <p>To transmit motion to the follower by direct contact</p> Signup and view all the answers

    What type of contact do the cam and the follower have?

    <p>Line contact</p> Signup and view all the answers

    What is the typical application of cams in Internal Combustion Engines?

    <p>Operating the inlet and exhaust valves</p> Signup and view all the answers

    What is the name of the follower that has a spherical surface in contact with the cam?

    <p>Spherical follower</p> Signup and view all the answers

    What is the type of cam that has an irregular contour to impart a specific motion to the follower?

    <p>Disk or plate cam</p> Signup and view all the answers

    What is the motion of the follower in a cylindrical cam?

    <p>Reciprocating motion</p> Signup and view all the answers

    What is the type of cam that has a contoured or grooved plate sliding on a guiding surface?

    <p>Translating cam</p> Signup and view all the answers

    What is the primary function of the cam in a cam-follower pair?

    <p>To transmit motion to the follower by direct contact</p> Signup and view all the answers

    What is the angle between the direction of the follower motion and a normal to the pitch curve?

    <p>Pressure angle</p> Signup and view all the answers

    What is the reference point on the follower used to generate the pitch curve?

    <p>Trace point</p> Signup and view all the answers

    What type of follower motion is characterized by a linear displacement variation with angular displacement?

    <p>Uniform velocity</p> Signup and view all the answers

    What is the circle drawn from the centre of the cam through the pitch points?

    <p>Pitch circle</p> Signup and view all the answers

    What is the purpose of displacement diagrams in cam follower systems?

    <p>To calculate the velocity and acceleration of the follower</p> Signup and view all the answers

    What is the type of motion executed by point P in Figure 3.9?

    <p>Simple harmonic motion</p> Signup and view all the answers

    What is the curve generated by the trace point as the follower moves relative to the cam?

    <p>Pitch curve</p> Signup and view all the answers

    What is the purpose of cam follower systems?

    <p>To achieve a desired oscillatory motion</p> Signup and view all the answers

    What is the type of motion that has a constant velocity during rise and fall?

    <p>Uniform velocity</p> Signup and view all the answers

    What is the diagram that plots the displacement of the follower against the angular displacement of the cam?

    <p>Displacement diagram</p> Signup and view all the answers

    What determines the contour or shape of the groove in a cam?

    <p>The specified motion of the follower</p> Signup and view all the answers

    What is the angle between the direction of the follower motion and a normal to the pitch curve?

    <p>Pressure angle</p> Signup and view all the answers

    What is the reference point on the follower used to generate the pitch curve?

    <p>Trace point</p> Signup and view all the answers

    What type of motion does the follower move with in Fig.3.8?

    <p>Uniform velocity</p> Signup and view all the answers

    What is the purpose of displacement diagrams in cam follower systems?

    <p>To plot the velocity and acceleration of the follower</p> Signup and view all the answers

    What is the motion executed by point Pl in Fig.3.9?

    <p>Simple harmonic motion</p> Signup and view all the answers

    What is the purpose of cam follower systems?

    <p>To achieve a desired oscillatory motion</p> Signup and view all the answers

    What is the circle drawn from the centre of the cam through the pitch points?

    <p>Pitch circle</p> Signup and view all the answers

    What is the smallest circle that can be drawn to the cam profile?

    <p>Base circle</p> Signup and view all the answers

    What is the centre of the roller in a roller follower?

    <p>Trace point</p> Signup and view all the answers

    What is the function of a cam in a cam-follower pair?

    <p>To transmit motion to a follower by direct contact</p> Signup and view all the answers

    What is the classification of followers based on the type of motion?

    <p>Based on type of motion</p> Signup and view all the answers

    What is a cylindrical cam?

    <p>A cam with a groove cut along its cylindrical surface</p> Signup and view all the answers

    What is the purpose of the follower in a cam-follower pair?

    <p>To transmit motion from the cam to other parts</p> Signup and view all the answers

    What is the classification of cams based on their physical shape?

    <p>Based on their physical shape</p> Signup and view all the answers

    What is the function of the springs or gravity in a cam-follower pair?

    <p>To hold the follower in contact with the cam</p> Signup and view all the answers

    What is the application of cams in internal combustion engines?

    <p>To operate the inlet and exhaust valves</p> Signup and view all the answers

    What is the type of follower that has a curved surface in contact with the cam?

    <p>Spherical follower</p> Signup and view all the answers

    What is the angle between the direction of the follower motion and a normal to the pitch curve?

    <p>Pressure angle</p> Signup and view all the answers

    What type of follower has the knife edge representing the trace point and the pitch curve corresponding to the cam profile?

    <p>Knife edge follower</p> Signup and view all the answers

    What is the term for the curve generated by the trace point as the follower moves relative to the cam?

    <p>Pitch curve</p> Signup and view all the answers

    What is the type of motion where the follower moves with constant velocity during rise and fall?

    <p>Uniform velocity</p> Signup and view all the answers

    What is the term for the diagram that plots the displacement of the follower against the angular displacement of the cam?

    <p>Displacement diagram</p> Signup and view all the answers

    What is the type of motion where the follower moves with a constant acceleration and deceleration?

    <p>Uniform acceleration and deceleration</p> Signup and view all the answers

    What is the term for the circle drawn from the centre of the cam through the pitch points?

    <p>Pitch circle</p> Signup and view all the answers

    What is the term for the point on the pitch curve having the maximum pressure angle?

    <p>Pitch point</p> Signup and view all the answers

    What is the type of follower motion where the follower raises, dwells, returns to its original position and dwells again through specified angles of rotation of the cam?

    <p>Oscillatory motion</p> Signup and view all the answers

    What is the term for the reference point on the follower used to generate the pitch curve?

    <p>Trace point</p> Signup and view all the answers

    What is the primary function of a cam in a mechanical system?

    <p>To transmit motion to a follower by direct contact</p> Signup and view all the answers

    What type of follower is used in an application where the surface in contact is a curved line?

    <p>Roller follower</p> Signup and view all the answers

    What is the primary difference between a disk cam and a cylindrical cam?

    <p>The shape of the cam</p> Signup and view all the answers

    What is the term for the motion of a follower that moves in a plane parallel to the axis of rotation of the camshaft?

    <p>Translating motion</p> Signup and view all the answers

    What is the primary application of cams in internal combustion engines?

    <p>Operating the inlet and exhaust valves</p> Signup and view all the answers

    What is the term for a cam that has a contoured or grooved plate sliding on a guiding surface?

    <p>Translating cam</p> Signup and view all the answers

    What is the primary characteristic of a cam and follower pair?

    <p>Higher pair with line contact</p> Signup and view all the answers

    What is the primary advantage of using cams in mechanical systems?

    <p>They can provide a specific motion to a follower</p> Signup and view all the answers

    What is the primary function of a belt drive?

    <p>To transmit power between shafts</p> Signup and view all the answers

    What is a characteristic of an open belt drive?

    <p>The driven pulley rotates in the same direction</p> Signup and view all the answers

    What is an advantage of belt drives?

    <p>They are lubrication-free</p> Signup and view all the answers

    What is a disadvantage of belt drives?

    <p>Angular velocity ratio is not constant</p> Signup and view all the answers

    What is the purpose of a crossed belt drive?

    <p>To rotate the driven pulley in the opposite direction</p> Signup and view all the answers

    Why is the tightened side of the belt kept on the lower side in horizontal drives?

    <p>To reduce the sag of the upper side</p> Signup and view all the answers

    What is a characteristic of belt drives when the distance between shafts is very large?

    <p>They are very economical</p> Signup and view all the answers

    What is a problem associated with crossed belt drives?

    <p>Bending and wear of the belt</p> Signup and view all the answers

    What is the main advantage of using a cone clutch?

    <p>The normal force acting on the friction surface is greater than the axial force</p> Signup and view all the answers

    What is the primary function of a clutch?

    <p>To transmit power from the engine to the transmission</p> Signup and view all the answers

    What type of clutch is commonly used in most modern light vehicles?

    <p>Single plate clutch</p> Signup and view all the answers

    What is the working principle of multiple clutches?

    <p>It is the same as a single-plate clutch</p> Signup and view all the answers

    What is the purpose of the spring in a centrifugal clutch?

    <p>To disengage the clutch at low speeds</p> Signup and view all the answers

    What happens when the clutch pedal is pressed?

    <p>The clutch plate becomes disengaged from the flywheel</p> Signup and view all the answers

    What type of clutch is operated in an oil bath?

    <p>Wet clutch</p> Signup and view all the answers

    What is the purpose of the flywheel in a clutch?

    <p>To rotate with the engine crankshaft</p> Signup and view all the answers

    What type of clutch uses multiple clutch plates to make frictional contact with a flywheel?

    <p>Multi-plate clutch</p> Signup and view all the answers

    What is the disadvantage of a cone clutch with an angle smaller than 20°?

    <p>The male cone binds in the female cone</p> Signup and view all the answers

    What type of force is used to keep the clutch in an engaged position in a centrifugal clutch?

    <p>Centrifugal force</p> Signup and view all the answers

    What is the purpose of the pressure plate in a single plate clutch?

    <p>To provide the axial force to keep the clutch engaged</p> Signup and view all the answers

    What happens when the engine speed increases in a centrifugal clutch?

    <p>The weights fly off due to centrifugal force</p> Signup and view all the answers

    What happens when the clutch pedal is released?

    <p>The clutch plate becomes engaged with the flywheel</p> Signup and view all the answers

    What is the main difference between a multiple clutch and a single-plate clutch?

    <p>The number of friction surfaces</p> Signup and view all the answers

    What type of clutch uses a diaphragm or conical type spring?

    <p>Conical spring clutch or Diaphragm clutch</p> Signup and view all the answers

    What is the purpose of the clutch spring in a single plate clutch?

    <p>To provide the axial force to keep the clutch engaged</p> Signup and view all the answers

    What type of vehicles use multiple clutches?

    <p>Heavy commercial vehicles, racing cars, and motorcycles</p> Signup and view all the answers

    What is the purpose of the bell crank levels in a centrifugal clutch?

    <p>To convert rotary motion to linear motion</p> Signup and view all the answers

    What is the type of clutch that uses hydraulic means to operate?

    <p>Hydraulic clutch</p> Signup and view all the answers

    What is the primary function of a belt drive?

    <p>To transmit power between shafts</p> Signup and view all the answers

    What is the main advantage of an open belt drive?

    <p>Rotating the driven pulley in the same direction</p> Signup and view all the answers

    What is a disadvantage of belt drives?

    <p>Angular velocity ratio is not constant</p> Signup and view all the answers

    What is the purpose of keeping the tightened side of the belt on the lower side in horizontal drives?

    <p>To reduce the sag of the upper side</p> Signup and view all the answers

    What is a characteristic of belt drives?

    <p>They are lubrication-free</p> Signup and view all the answers

    What is a benefit of using belt drives when the distance between shafts is very large?

    <p>Economical use</p> Signup and view all the answers

    What is a crossed belt drive used for?

    <p>To rotate the driven pulley in the opposite direction</p> Signup and view all the answers

    What is a benefit of using belt drives?

    <p>Noise and vibration are damped out</p> Signup and view all the answers

    What is the primary function of a clutch in a vehicle?

    <p>To transmit torque from the engine to the transmission input shaft</p> Signup and view all the answers

    What is the main advantage of a multi-plate clutch over a single-plate clutch?

    <p>It provides more frictional contact between the flywheel and the clutch plate</p> Signup and view all the answers

    What is the purpose of the pressure plate in a single-plate clutch?

    <p>To provide axial force to keep the clutch engaged</p> Signup and view all the answers

    What happens to the clutch plate when the clutch pedal is pressed?

    <p>It becomes free between the pressure plate and flywheel</p> Signup and view all the answers

    What type of clutch is commonly used in American passenger cars?

    <p>Dry single-plate clutch</p> Signup and view all the answers

    What is the purpose of the clutch spring in a single-plate clutch?

    <p>To provide axial force to keep the clutch engaged</p> Signup and view all the answers

    What is the primary function of the flywheel in a clutch?

    <p>To rotate with the engine crankshaft</p> Signup and view all the answers

    What type of clutch uses multiple friction plates to transmit power?

    <p>Multi-plate clutch</p> Signup and view all the answers

    What is the operating temperature range of a clutch?

    <p>-35 to 85°C</p> Signup and view all the answers

    What is the power transmission limit of a clutch?

    <p>370 kilowatts</p> Signup and view all the answers

    What is the main advantage of cone clutch over single-plate clutch?

    <p>Greater normal force acting on the friction surface</p> Signup and view all the answers

    What is the purpose of the spring G in a centrifugal clutch?

    <p>To keep the clutch disengaged at low speeds</p> Signup and view all the answers

    What is the primary difference between a wet clutch and a dry clutch?

    <p>The presence of oil bath</p> Signup and view all the answers

    Why are cone clutches becoming less popular?

    <p>Due to the difficulty in disengaging the clutch and wear on the cone surfaces</p> Signup and view all the answers

    What is the purpose of the centrifugal force in a centrifugal clutch?

    <p>To operate the clutch automatically depending on the engine speed</p> Signup and view all the answers

    What is the main advantage of a multiple clutch over a single-plate clutch?

    <p>More friction surface</p> Signup and view all the answers

    What type of vehicles typically use multiple clutches?

    <p>Heavy commercial vehicles, racing cars, and motorcycles</p> Signup and view all the answers

    What is the purpose of the stop H in a centrifugal clutch?

    <p>To limit the movement of the weights due to the centrifugal force</p> Signup and view all the answers

    What happens to the male cone when the clutch pedal is pressed in a cone clutch?

    <p>It slides away from the spring force</p> Signup and view all the answers

    What is the advantage of using a centrifugal clutch over a traditional clutch?

    <p>It allows the driver to stop the vehicle in any gear without stalling the engine</p> Signup and view all the answers

    What is the primary function of a clutch in a vehicle?

    <p>To engage and disengage power transmission</p> Signup and view all the answers

    What is the main disadvantage of belt drives?

    <p>Limited speed and power transmission</p> Signup and view all the answers

    What type of clutch is commonly used in most modern light vehicles?

    <p>Single plate clutch</p> Signup and view all the answers

    What happens when the clutch pedal is pressed in a vehicle?

    <p>The clutch plate becomes free between the pressure plate and flywheel</p> Signup and view all the answers

    What is the purpose of the friction plate in a single-plate clutch?

    <p>To provide frictional contact between the clutch plate and flywheel</p> Signup and view all the answers

    What type of clutch uses a two friction plate and an intermediate pressure plate?

    <p>Heavy-duty clutch</p> Signup and view all the answers

    What is the primary difference between a single plate clutch and a multi-plate clutch?

    <p>The number of friction plates</p> Signup and view all the answers

    What is the term for the mechanism that engages and disengages the power transmission from the driving shaft to the driven shaft?

    <p>Clutch</p> Signup and view all the answers

    What is the purpose of the pressure plate in a single-plate clutch?

    <p>To provide axial force to keep the clutch engaged</p> Signup and view all the answers

    What is the name of the type of clutch that uses hydraulic means for operation?

    <p>Hydraulic clutch</p> Signup and view all the answers

    What is the main advantage of using a cone clutch over a single-plate clutch?

    <p>The normal force acting on the friction surface is greater than the axial force</p> Signup and view all the answers

    What happens to the male cone in a cone clutch when the clutch pedal is pressed?

    <p>It slides away from the spring force</p> Signup and view all the answers

    What is the primary difference between a wet clutch and a dry clutch?

    <p>The presence or absence of oil in the clutch</p> Signup and view all the answers

    What is the purpose of the weights in a centrifugal clutch?

    <p>To generate centrifugal force</p> Signup and view all the answers

    What is the main advantage of using a centrifugal clutch over a traditional clutch?

    <p>It does not require a clutch pedal to operate</p> Signup and view all the answers

    What is the purpose of spring G in a centrifugal clutch?

    <p>To keep the clutch disengaged</p> Signup and view all the answers

    What happens to the male cone in a cone clutch if the angle of the cone is made smaller than 20°?

    <p>It binds in the female cone</p> Signup and view all the answers

    What is the primary disadvantage of using a cone clutch?

    <p>The male cone tends to bind in the female cone if the angle of the cone is made smaller than 20°</p> Signup and view all the answers

    What is the main difference between a multiple clutch and a single-plate clutch?

    <p>The number of friction surfaces</p> Signup and view all the answers

    What is the purpose of the clutch plates in a multiple clutch?

    <p>To transmit torque between the engine shaft and the transmission shaft</p> Signup and view all the answers

    What is the primary advantage of using a belt drive in a machine?

    <p>To damp out noise and vibration</p> Signup and view all the answers

    What type of belt drive is used to rotate the driven pulley in the same direction of driving pulley?

    <p>Open belt drive</p> Signup and view all the answers

    What is the primary concern in using a crossed belt drive?

    <p>Bending and wear of the belt</p> Signup and view all the answers

    What is the advantage of using belt drives in machines with large distances between shafts?

    <p>They are very economical</p> Signup and view all the answers

    What is the purpose of keeping the tightened side of the belt on the lower side of two pulleys in horizontal drives?

    <p>To reduce the sag of the upper side</p> Signup and view all the answers

    What is the primary advantage of using belt drives in machines?

    <p>They are simple and economical</p> Signup and view all the answers

    What is the effect of belt drives on the machinery life?

    <p>It increases the machinery life</p> Signup and view all the answers

    What is the efficiency of belt drives in use?

    <p>Up to 98%</p> Signup and view all the answers

    What is the primary reason for the high efficiency of gears?

    <p>Due to primarily rolling contact between the teeth</p> Signup and view all the answers

    What is the main advantage of using gears over belt, rope, and chain drives?

    <p>All of the above</p> Signup and view all the answers

    What happens when the tangential force exerted by wheel A exceeds the frictional resistance between wheel A and wheel B?

    <p>Slipping will take place between the two wheels</p> Signup and view all the answers

    What is the purpose of providing teeth on the periphery of wheel A?

    <p>To avoid slipping between wheel A and wheel B</p> Signup and view all the answers

    What is the disadvantage of gear drive?

    <p>The manufacture of gears requires special tools and equipment</p> Signup and view all the answers

    What is the primary function of gear teeth?

    <p>To allow positive engagement between teeth</p> Signup and view all the answers

    What is the result of the error in cutting teeth in gear drive?

    <p>It causes vibrations and noise during operation</p> Signup and view all the answers

    What is the characteristic of the motion transmitted by gears?

    <p>It is positive</p> Signup and view all the answers

    What is the most common type of gear?

    <p>Spur gear</p> Signup and view all the answers

    What is the main advantage of helical gears over spur gears?

    <p>They operate more smoothly and quietly</p> Signup and view all the answers

    What is the main disadvantage of spur gears?

    <p>Each tooth engagement causes impact and stress</p> Signup and view all the answers

    What is the function of a rack and pinion?

    <p>To convert rotational motion to translational motion</p> Signup and view all the answers

    What type of gear is used to connect intersecting shafts?

    <p>Bevel gear</p> Signup and view all the answers

    What is the advantage of spiral teeth in bevel gears?

    <p>They engage smoothly and reduce stress</p> Signup and view all the answers

    What is the difference between helical gears and spur gears?

    <p>Helical gears have teeth cut at an angle</p> Signup and view all the answers

    What is the advantage of helical gears over spur gears in terms of load carrying capacity?

    <p>Helical gears can carry more load</p> Signup and view all the answers

    What is the purpose of bearings in devices that use helical gears?

    <p>To support the thrust load</p> Signup and view all the answers

    What is the main difference between helical gears and herringbone gears?

    <p>Helical gears have a single helix, while herringbone gears have a double helix</p> Signup and view all the answers

    What is the advantage of having a lower input pinion in a hypoid gear?

    <p>It provides more room for people and cargo in the passenger compartment</p> Signup and view all the answers

    What type of gear is used when large gear reductions are needed?

    <p>Worm gear</p> Signup and view all the answers

    What is the radial distance between the Pitch Circle and the top of the teeth?

    <p>Addendum</p> Signup and view all the answers

    What is the term for the point of tangency of the pitch circles of two meshing gears?

    <p>Pitch Point</p> Signup and view all the answers

    What is the term for the circle that passes through the bottom of the tooth spaces?

    <p>Root Circle</p> Signup and view all the answers

    What is the length of path of contact in the involute system?

    <p>KP + PL</p> Signup and view all the answers

    What is the term for the ratio of the length of the Arc of Action to the Circular Pitch?

    <p>Contact Ratio</p> Signup and view all the answers

    What is the point of contact between the two teeth always on?

    <p>Involute profiles</p> Signup and view all the answers

    What is the term for the working surface of a gear tooth, located between the pitch diameter and the top of the tooth?

    <p>Face</p> Signup and view all the answers

    What is the term for the distance between the top of a tooth and the bottom of the space into which it fits on the meshing gear?

    <p>Clearance</p> Signup and view all the answers

    What is interference in involute gears?

    <p>The phenomenon when the tip of tooth undercuts the root on its mating gear</p> Signup and view all the answers

    What is the term for the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth?

    <p>Backlash</p> Signup and view all the answers

    What is the term for the smaller of two meshed gears?

    <p>Pinion</p> Signup and view all the answers

    What is the term for the line along which the point of contact between gear teeth travels?

    <p>Line of Action</p> Signup and view all the answers

    What is the effect of increasing the radius of the addendum circles of the wheel?

    <p>Interference occurs</p> Signup and view all the answers

    What is the minimum number of teeth on the pinion to avoid interference?

    <p>t</p> Signup and view all the answers

    What is the point of intersection of the addendum circle of wheel and the common tangent?

    <p>K</p> Signup and view all the answers

    What is the radius of the base circle of pinion?

    <p>r cos</p> Signup and view all the answers

    What is the path of approach?

    <p>KP</p> Signup and view all the answers

    What is the angle of action of the pinion and the gear wheel?

    <p>f</p> Signup and view all the answers

    What is the fundamental law of gear-tooth action?

    <p>A common normal to the tooth profiles at their point of contact must pass through a fixed point on the line of centers.</p> Signup and view all the answers

    What is the purpose of the pitch point in gear-tooth action?

    <p>To divide the line of centers and determine the velocity ratio.</p> Signup and view all the answers

    What is the characteristic of involute profiles that makes them widely used in gear design?

    <p>They are easy to manufacture and the center distance can be varied.</p> Signup and view all the answers

    What is the definition of conjugate profiles?

    <p>Profiles that satisfy the fundamental law of gear-tooth action.</p> Signup and view all the answers

    What is the purpose of the pitch circles in gear-tooth action?

    <p>To determine the velocity ratio of the gears.</p> Signup and view all the answers

    What is the condition for a constant velocity ratio in gear-tooth action?

    <p>The pitch point must remain unchanged.</p> Signup and view all the answers

    What is the definition of the involute curve?

    <p>The path traced by a point on a line as the line rolls without slipping on the circumference of a circle.</p> Signup and view all the answers

    What is the importance of the conjugate action in gear design?

    <p>It is essential for correctly meshing gears and ensures that the speed ratio remains constant during an increment of rotation.</p> Signup and view all the answers

    What is the characteristic of the cycloidal and involute profiles?

    <p>They are easy to manufacture and the center distance can be varied.</p> Signup and view all the answers

    What is the name of the circle from which the involute is derived?

    <p>Base circle</p> Signup and view all the answers

    What is the advantage of involute gears in terms of manufacturing?

    <p>They are easier to manufacture than cycloidal gears</p> Signup and view all the answers

    What is the advantage of cycloidal gears in terms of strength?

    <p>They are stronger than involute gears due to wider flanks</p> Signup and view all the answers

    What is the difference between the pressure angle in involute and cycloidal gears?

    <p>The pressure angle is constant in involute gears and varies in cycloidal gears</p> Signup and view all the answers

    What is the advantage of involute gears in terms of smooth running?

    <p>They have a constant pressure angle</p> Signup and view all the answers

    What is the name of the system of gear teeth that uses cycloidal curves at the top and bottom and an involute curve at the middle portion?

    <p>14 1/2O Composite system</p> Signup and view all the answers

    What is the advantage of increasing the pressure angle from 14 1/2O to 20O in the full depth involute system?

    <p>It results in a stronger tooth</p> Signup and view all the answers

    What is the difference between the 14 1/2O Composite system and the 14 1/2O Full depth involute system?

    <p>The 14 1/2O Composite system has cycloidal curves at the top and bottom, while the 14 1/2O Full depth involute system has an involute curve at the middle portion</p> Signup and view all the answers

    What is the advantage of the 20O Full depth involute system?

    <p>It is stronger than the 14 1/2O Full depth involute system</p> Signup and view all the answers

    What is the primary difference between the 20O Full depth involute system and the 20O Stub involute system?

    <p>The 20O Full depth involute system has a full-depth tooth, while the 20O Stub involute system has a stub tooth</p> Signup and view all the answers

    What is the primary reason gears are highly efficient?

    <p>Rolling contact between the teeth</p> Signup and view all the answers

    What is the purpose of providing projections on the periphery of the wheel?

    <p>To avoid slipping between the two wheels</p> Signup and view all the answers

    What is the advantage of gear drive compared to belt, rope, and chain drives?

    <p>It transmits exact velocity ratio</p> Signup and view all the answers

    What is the disadvantage of gear drive?

    <p>The manufacture of gears requires special tools and equipment</p> Signup and view all the answers

    What type of drive is not positive due to the possibility of slipping?

    <p>Friction drive</p> Signup and view all the answers

    What is the term for a wheel with teeth cut on it?

    <p>Toothed wheel</p> Signup and view all the answers

    What is the result when the tangential force exceeds the maximum frictional resistance between the two wheels?

    <p>Slipping between the two wheels</p> Signup and view all the answers

    What is the characteristic of gears that allows them to transmit large power?

    <p>Ability to minimize friction</p> Signup and view all the answers

    What is the primary function of a rack and pinion gear system?

    <p>To convert rotational motion to translational motion</p> Signup and view all the answers

    What is the advantage of helical gears over spur gears?

    <p>Helical gears operate more smoothly and quietly than spur gears</p> Signup and view all the answers

    What type of gears are used to connect intersecting shafts?

    <p>Bevel gears</p> Signup and view all the answers

    What is the characteristic of a spur gear?

    <p>Teeth are perpendicular to the face of the gear</p> Signup and view all the answers

    What is the limitation of spur gears?

    <p>Cannot be used when a direction change between the two shafts is required</p> Signup and view all the answers

    What is the advantage of helical gears in terms of tooth strength?

    <p>Tooth strength is greater because the teeth are longer</p> Signup and view all the answers

    What type of gears have teeth that are cut at an angle to the face of the gear?

    <p>Helical gears</p> Signup and view all the answers

    What is the feature of hypoid gears?

    <p>The axes can be in different planes</p> Signup and view all the answers

    What is the purpose of curved teeth in bevel gears?

    <p>To reduce the noise and stress in the gears</p> Signup and view all the answers

    What type of gears are used in almost all car transmissions?

    <p>Helical gears</p> Signup and view all the answers

    What is the advantage of having a lower input pinion in a hypoid gear?

    <p>It makes more room for people and cargo</p> Signup and view all the answers

    What is the primary application of helical gears?

    <p>In parallel shaft applications</p> Signup and view all the answers

    What is the characteristic of worm gears that makes them useful for conveyor systems?

    <p>The gear cannot turn the worm</p> Signup and view all the answers

    What is the term for the radial distance between the Pitch Circle and the top of the teeth?

    <p>Addendum</p> Signup and view all the answers

    What is the term for the circle from which the involute curve is generated?

    <p>Base Circle</p> Signup and view all the answers

    What is the term for the distance between the top of a tooth and the bottom of the space into which it fits?

    <p>Clearance</p> Signup and view all the answers

    What is the term for the line along which the point of contact between gear teeth travels?

    <p>Line of Action</p> Signup and view all the answers

    What is the term for the point of tangency of the pitch circles of two meshing gears?

    <p>Pitch Point</p> Signup and view all the answers

    What is the fundamental law of gear-tooth action?

    <p>The tooth profile 1 drives tooth profile 2 by acting at the instantaneous contact point K</p> Signup and view all the answers

    What is the name of the differential used in some high-performance cars and trucks?

    <p>Torsen differential</p> Signup and view all the answers

    What is the name of the circle from which the involute is derived?

    <p>Base circle</p> Signup and view all the answers

    What is the advantage of involute gears in terms of manufacturing?

    <p>They are easier to manufacture</p> Signup and view all the answers

    What is the advantage of cycloidal gears in terms of strength?

    <p>They are stronger than involute gears due to wider flanks</p> Signup and view all the answers

    What is the difference between involute and cycloidal gears in terms of pressure angle?

    <p>The pressure angle remains constant in involute gears but varies in cycloidal gears</p> Signup and view all the answers

    What is the system of gear teeth used for general purpose gears?

    <p>14 1/2O Composite system</p> Signup and view all the answers

    What is the advantage of 20O Full depth involute system over 14 1/2O Full depth involute system?

    <p>The tooth is stronger in 20O Full depth involute system</p> Signup and view all the answers

    What is the characteristic of the involute curve?

    <p>It is a single curvature</p> Signup and view all the answers

    What is the advantage of cycloidal gears in terms of wear?

    <p>They have less wear than involute gears</p> Signup and view all the answers

    What is the point where the contact between a pair of involute teeth begins?

    <p>At K (on the near the base circle of pinion or the outer end of the tooth face on the wheel)</p> Signup and view all the answers

    What is the problem with involute gears?

    <p>They have interference problem</p> Signup and view all the answers

    What is the length of the path of contact?

    <p>The sum of the parts of path of contacts KP and PL</p> Signup and view all the answers

    What is the characteristic of the cycloidal curve?

    <p>It is a double curvature</p> Signup and view all the answers

    What is interference in involute gears?

    <p>The phenomenon when the tip of tooth undercuts the root on its mating gear</p> Signup and view all the answers

    What is the formula to find the radius of the base circle of the pinion?

    <p>r = O1P cos</p> Signup and view all the answers

    What is the purpose of reducing the height of the teeth?

    <p>To avoid interference</p> Signup and view all the answers

    What is backlash?

    <p>The gap between the non-drive face of the pinion tooth and the adjacent wheel tooth</p> Signup and view all the answers

    What is the term for the point where the addendum circles of the wheel and pinion cut the common tangent?

    <p>Point of tangency</p> Signup and view all the answers

    What is the minimum number of teeth on the pinion to avoid interference?

    <p>'t'</p> Signup and view all the answers

    What is the direction of the motion of the tool in a quick return motion mechanism?

    <p>Reciprocating</p> Signup and view all the answers

    What is the purpose of the short link PR in a quick return motion mechanism?

    <p>To change the direction of motion</p> Signup and view all the answers

    What is the fundamental law of gear-tooth action?

    <p>A common normal to the tooth profiles at their point of contact must pass through a fixed point on the line-of-centers.</p> Signup and view all the answers

    What is the significance of the pitch point in gear-tooth action?

    <p>It is the point where the velocity ratio is decided.</p> Signup and view all the answers

    What is the relationship between the angular velocities of the driving gear and the driven gear?

    <p>The angular velocity of the driving gear is inversely proportional to the radius of the driven gear.</p> Signup and view all the answers

    What type of tooth profiles are commonly used in gears?

    <p>Involute profiles</p> Signup and view all the answers

    What is the advantage of using involute profiles in gears?

    <p>They are easier to manufacture.</p> Signup and view all the answers

    What is the definition of conjugate profiles?

    <p>Two profiles that satisfy the fundamental law of gear-tooth action.</p> Signup and view all the answers

    What is the purpose of the pitch point in conjugate profiles?

    <p>To determine the velocity ratio of the gears.</p> Signup and view all the answers

    What is the characteristic of the involute curve?

    <p>It is a path traced by a point on a line as the line rolls without slipping on the circumference of a circle.</p> Signup and view all the answers

    What is the requirement for conjugate action in gears?

    <p>The module of the teeth must be the same for both gears.</p> Signup and view all the answers

    What is the significance of the velocity ratio in gear-tooth action?

    <p>It is the ratio of the rotary velocity of the driver gear to that of the driven gear.</p> Signup and view all the answers

    What is the primary reason why gears are highly efficient?

    <p>Due to the primarily rolling contact between the teeth</p> Signup and view all the answers

    What is the purpose of providing projections (called teeth) on the periphery of the wheel A?

    <p>To avoid slipping between the two wheels</p> Signup and view all the answers

    What is the primary advantage of gear drive over belt, rope, and chain drives?

    <p>It transmits exact velocity ratio</p> Signup and view all the answers

    What is the characteristic of the motion transmitted by gears?

    <p>Positive</p> Signup and view all the answers

    What is the primary reason why friction drive is not a positive drive?

    <p>Due to the possibility of slipping between the two wheels</p> Signup and view all the answers

    What is the primary disadvantage of gear drive?

    <p>The manufacture of gears requires special tools and equipment</p> Signup and view all the answers

    What is the term for the wheel with teeth cut on it?

    <p>Toothed wheel or gear</p> Signup and view all the answers

    What is the purpose of providing teeth on the periphery of the wheel A and corresponding recesses on the periphery of the wheel B?

    <p>To allow positive engagement between teeth</p> Signup and view all the answers

    What is the primary advantage of using helical gears over spur gears?

    <p>Helical gears are quieter and smoother in operation due to gradual engagement</p> Signup and view all the answers

    What is the primary function of a rack in a rack and pinion system?

    <p>To convert rotational motion to translational motion</p> Signup and view all the answers

    What is the primary advantage of using bevel gears?

    <p>They can transmit motion between perpendicular shafts</p> Signup and view all the answers

    What is the primary difference between straight bevel gears and spiral bevel gears?

    <p>Spiral bevel gears have a smoother engagement than straight bevel gears</p> Signup and view all the answers

    What is the primary advantage of using herringbone gears?

    <p>They can cancel out axial thrust loads</p> Signup and view all the answers

    What is the primary characteristic of spur gears?

    <p>They have teeth perpendicular to the face of the gear</p> Signup and view all the answers

    What is the fundamental law of gear-tooth action?

    <p>The velocity ratio is equal to the inverse ratio of the diameters of pitch circles.</p> Signup and view all the answers

    What is the primary disadvantage of using spur gears?

    <p>They are noisy and produce impact loading</p> Signup and view all the answers

    What is the primary application of rack and pinion systems?

    <p>In steering systems</p> Signup and view all the answers

    What is the purpose of the pitch point in gear-tooth action?

    <p>To divide the line of centers and decide the velocity ratio of the two teeth.</p> Signup and view all the answers

    What type of profile has important advantages in terms of manufacturability and varying center distance?

    <p>Involute profile</p> Signup and view all the answers

    What is the primary difference between helical gears and herringbone gears?

    <p>Helical gears have two rows of teeth, while herringbone gears have one row of teeth</p> Signup and view all the answers

    What is the name of the curve most commonly used for gear-tooth profiles?

    <p>Involute curve</p> Signup and view all the answers

    What is the primary advantage of using gears for connecting parallel shafts?

    <p>They can provide a large gear reduction in a small space</p> Signup and view all the answers

    What is the path traced by a point on a line as the line rolls without slipping on the circumference of a circle?

    <p>Involute curve</p> Signup and view all the answers

    What is the term for the tooth profiles that satisfy the fundamental law of gear-tooth action?

    <p>Conjugate profiles</p> Signup and view all the answers

    What is the requirement for obtaining the expected velocity ratio of two tooth profiles?

    <p>The normal line of their profiles must pass through the corresponding pitch point.</p> Signup and view all the answers

    What is the term for the curves or profiles engaging each other and satisfying the law of gearing?

    <p>Conjugate curves</p> Signup and view all the answers

    What is the importance of the pitch point in conjugate profiles?

    <p>It decides the velocity ratio of the two teeth.</p> Signup and view all the answers

    What is the name of the mechanism used in shaping machines, slotting machines, and rotary internal combustion engines?

    <p>Quick return motion mechanism</p> Signup and view all the answers

    What is the primary advantage of using hypoid gears in a differential?

    <p>Lowered driveshaft and increased passenger space</p> Signup and view all the answers

    What is the unique property of worm gears that no other gear set has?

    <p>The worm can easily turn the gear, but the gear cannot turn the worm</p> Signup and view all the answers

    What is the term for the radial distance between the Pitch Circle and the top of the teeth?

    <p>Addendum</p> Signup and view all the answers

    What is the term for the circle from which the involute curve upon which the tooth profile is based?

    <p>Base Circle</p> Signup and view all the answers

    What is the term for the ratio of the length of the Arc of Action to the Circular Pitch?

    <p>Contact Ratio</p> Signup and view all the answers

    What is the term for the line along which the point of contact between gear teeth travels?

    <p>Line of Action</p> Signup and view all the answers

    What is the term for the point of tangency of the pitch circles of two meshing gears?

    <p>Pitch Point</p> Signup and view all the answers

    What is the fundamental law of gear-tooth action?

    <p>The common normal to the two profiles passes through the pitch point</p> Signup and view all the answers

    What is the term for the circle that passes through the bottom of the tooth spaces?

    <p>Root Circle</p> Signup and view all the answers

    What is the term for the smaller of two meshed gears?

    <p>Pinion</p> Signup and view all the answers

    What is the primary advantage of involute gears over cycloidal gears?

    <p>Involute gears are easier to manufacture and have more flexibility</p> Signup and view all the answers

    What is the characteristic of the tooth profile in the 141/2O composite system?

    <p>The tooth profile has a double curvature, with cycloidal curves at the top and bottom and an involute curve in the middle</p> Signup and view all the answers

    What is the main advantage of cycloidal gears over involute gears?

    <p>Cycloidal gears are stronger due to their wider flanks</p> Signup and view all the answers

    What is the purpose of the involute curve in gear design?

    <p>To provide a constant pressure angle throughout the engagement</p> Signup and view all the answers

    What is the main disadvantage of cycloidal gears compared to involute gears?

    <p>Cycloidal gears are more difficult to manufacture due to their double curvature</p> Signup and view all the answers

    What is the primary difference between the 141/2O full depth involute system and the 20O full depth involute system?

    <p>The pressure angle is different between the two systems</p> Signup and view all the answers

    What is the advantage of the 20O full depth involute system compared to the 141/2O full depth involute system?

    <p>The 20O system has a higher pressure angle, resulting in increased strength</p> Signup and view all the answers

    What is the characteristic of the cycloidal profile?

    <p>The cycloidal profile has a double curvature, with epi-cycloidal and hypo-cycloidal curves</p> Signup and view all the answers

    What is the main advantage of involute gears over cycloidal gears in terms of manufacturing?

    <p>Involute gears have a single curvature, making them easier to manufacture</p> Signup and view all the answers

    What is the primary reason why cycloidal gears are not widely used in modern gear design?

    <p>Cycloidal gears are more difficult to manufacture due to their double curvature</p> Signup and view all the answers

    What is the length of path of contact between the pinion and the wheel?

    <p>KP + PL</p> Signup and view all the answers

    What is the condition to prevent interference in involute gears?

    <p>Both A and B</p> Signup and view all the answers

    What is the term for the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth?

    <p>Backlash</p> Signup and view all the answers

    What is the effect of undercutting the tooth on the wheel at the root?

    <p>It damages part of the involute profile</p> Signup and view all the answers

    What is the radius of the base circle of the pinion?

    <p>r cos</p> Signup and view all the answers

    What is the radius of the addendum circle of the pinion?

    <p>r + addendum</p> Signup and view all the answers

    What is the formula for the length of path of contact?

    <p>√(RA^2 - R^2) + √(ra^2 - r^2)</p> Signup and view all the answers

    What is the minimum number of teeth on the pinion to avoid interference?

    <p>t</p> Signup and view all the answers

    What is the term for the angle of action of the pinion and the gear wheel?

    <p>Angle of action</p> Signup and view all the answers

    What is the formula for the pitch circle radius of the pinion?

    <p>mt</p> Signup and view all the answers

    What is the primary reason for the high efficiency of gears?

    <p>Because of the rolling contact between the teeth</p> Signup and view all the answers

    What is the main advantage of using gears over friction wheels?

    <p>Gears provide a positive drive</p> Signup and view all the answers

    What is the purpose of providing teeth on the periphery of a wheel?

    <p>To provide a positive drive</p> Signup and view all the answers

    What is the disadvantage of gear manufacturing?

    <p>Gears require special tools and equipment</p> Signup and view all the answers

    What is the benefit of using gears in power transmission?

    <p>Gears provide a reliable and efficient power transmission</p> Signup and view all the answers

    What happens when the tangential force exerted by a wheel exceeds the maximum frictional resistance?

    <p>Slipping takes place between the wheels</p> Signup and view all the answers

    What is the term for the path generated by a point attached to the coupler during the motion of a mechanism?

    <p>Locus</p> Signup and view all the answers

    What is the characteristic of motion in gears?

    <p>The motion is primarily rolling</p> Signup and view all the answers

    What is the primary advantage of using hypoid gears in a differential?

    <p>It lowers the driveshaft, making more room for people and cargo</p> Signup and view all the answers

    What is the characteristic of worm gears that makes them useful for machines such as conveyor systems?

    <p>The worm can easily turn the gear, but the gear cannot turn the worm</p> Signup and view all the answers

    What is the term for the radial distance between the Pitch Circle and the top of the teeth?

    <p>Addendum</p> Signup and view all the answers

    What is the term for the circle from which the involute curve is generated?

    <p>Base Circle</p> Signup and view all the answers

    What is the term for the point of tangency of the pitch circles of two meshing gears?

    <p>Pitch Point</p> Signup and view all the answers

    What is the term for the ratio of the length of the Arc of Action to the Circular Pitch?

    <p>Contact Ratio</p> Signup and view all the answers

    What is the purpose of helical gears?

    <p>To mesh two shafts that are perpendicular</p> Signup and view all the answers

    What is the term for the working surface of a gear tooth?

    <p>Face</p> Signup and view all the answers

    What is the term for the smaller of two meshed gears?

    <p>Pinion</p> Signup and view all the answers

    What is the Fundamental Law of Gear-Tooth Action?

    <p>The law of equal and opposite normal forces</p> Signup and view all the answers

    What is the fundamental law of gear-tooth action?

    <p>A common normal to the tooth profiles at their point of contact must, in all positions of the contacting teeth, pass through a fixed point on the line-of-centers called the pitch point.</p> Signup and view all the answers

    What is the purpose of the pitch point in gear-tooth action?

    <p>To ensure constant velocity ratio between the mating gears.</p> Signup and view all the answers

    What is the relationship between the angular velocities of the driving gear and the driven gear?

    <p>The angular velocity of the driving gear is equal to the inverse ratio of the diameters of the pitch circles.</p> Signup and view all the answers

    What is the involute curve used in gear-tooth action?

    <p>All of the above</p> Signup and view all the answers

    What is the importance of the pitch point in ensuring conjugate action?

    <p>It ensures that the normal line of the tooth profiles passes through the pitch point.</p> Signup and view all the answers

    What is the condition for conjugate action between two tooth profiles?

    <p>The normal line of the tooth profiles must pass through the pitch point.</p> Signup and view all the answers

    What is the advantage of using involute profiles in gear-tooth action?

    <p>All of the above</p> Signup and view all the answers

    What is the consequence of not satisfying the fundamental law of gear-tooth action?

    <p>The tooth profiles will separate from each other.</p> Signup and view all the answers

    What is the purpose of the pitch circles in gear-tooth action?

    <p>To determine the velocity ratio of the mating gears.</p> Signup and view all the answers

    What is the type of motion of the mating gears in gear-tooth action?

    <p>Rotary motion.</p> Signup and view all the answers

    What type of gears are commonly used in car transmission?

    <p>Helical gears</p> Signup and view all the answers

    What is the primary advantage of using helical gears over spur gears?

    <p>Smoother and quieter operation</p> Signup and view all the answers

    What type of gears are used to convert rotational motion to translational motion?

    <p>Rack and pinion gears</p> Signup and view all the answers

    What is the primary difference between helical gears and spur gears?

    <p>Angle of the teeth</p> Signup and view all the answers

    What is the advantage of using spiral bevel gears over straight bevel gears?

    <p>Smoother and quieter operation</p> Signup and view all the answers

    What type of gears are used to connect intersecting shafts?

    <p>Bevel gears</p> Signup and view all the answers

    What is the primary advantage of using herringbone gears?

    <p>Thrust load cancellation</p> Signup and view all the answers

    What is the primary difference between spur gears and helical gears in terms of tooth strength?

    <p>Helical gears have longer teeth</p> Signup and view all the answers

    What is the primary disadvantage of using helical gears?

    <p>Thrust load creation</p> Signup and view all the answers

    What is the primary application of rack and pinion gears?

    <p>Rack and pinion steering system</p> Signup and view all the answers

    What is the primary advantage of the involute curve in gear design?

    <p>It is easy to manufacture and allows for variation in center distance without changing velocity ratio</p> Signup and view all the answers

    What is the primary difference between the involute and cycloidal gear teeth?

    <p>The involute gear has a single curvature, while the cycloidal gear has a double curvature</p> Signup and view all the answers

    What is the advantage of the 20O full depth involute system compared to the 14 1/2O full depth involute system?

    <p>The 20O system has a stronger tooth due to a wider base</p> Signup and view all the answers

    What is the characteristic of the cycloidal gear teeth that makes them stronger than involute gears?

    <p>Wider flanks</p> Signup and view all the answers

    What is the primary advantage of the 14 1/2O composite system?

    <p>It is stronger but has no interchangeability</p> Signup and view all the answers

    What is the characteristic of the involute gear teeth that makes them easy to manufacture?

    <p>Single curvature</p> Signup and view all the answers

    What is the primary difference between the involute and cycloidal gear teeth in terms of wear?

    <p>The cycloidal gear has less wear due to convex surfaces engaging with concave flanks</p> Signup and view all the answers

    What is the primary advantage of the involute gear system?

    <p>Greater simplicity and flexibility</p> Signup and view all the answers

    What is the characteristic of the cycloidal gear teeth that makes them preferred for cast teeth?

    <p>Wider flanks</p> Signup and view all the answers

    What is the primary difference between the 14 1/2O composite system and the 20O full depth involute system?

    <p>The 14 1/2O system has a cycloidal curve at the top and bottom</p> Signup and view all the answers

    What is the primary purpose of reducing the height of the teeth in a gear system?

    <p>To prevent interference between the teeth</p> Signup and view all the answers

    What is the term for the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth?

    <p>Backlash</p> Signup and view all the answers

    What is the purpose of increasing the centre distance between the pinion and the wheel?

    <p>To prevent interference between the teeth</p> Signup and view all the answers

    What is the formula for the radius of the base circle of the pinion?

    <p>r cos</p> Signup and view all the answers

    What is the term for the phenomenon where the tip of the tooth on one gear undercuts the root of the tooth on the mating gear?

    <p>Interference</p> Signup and view all the answers

    What is the purpose of the common tangent to the base circles of the pinion and the wheel?

    <p>To determine the path of contact between the gears</p> Signup and view all the answers

    What is the formula for the length of the path of contact between the gears?

    <p>KL = KP + PL</p> Signup and view all the answers

    What is the purpose of the addendum circle of the pinion?

    <p>To provide clearance for the teeth on the mating gear</p> Signup and view all the answers

    What is the minimum number of teeth on the pinion required to avoid interference between the gears?

    <p>Depends on the specific gear system</p> Signup and view all the answers

    What is the term for the angle of action of the pinion and the wheel?

    <p>Angle of action</p> Signup and view all the answers

    Study Notes

    Mechanics: Study of Motion, Time, and Force

    • Mechanics is a branch of scientific analysis that deals with motion, time, and force.
    • Kinematics is the study of motion without considering the forces that produce that motion.
    • Kinematics of machines deals with the study of the relative motion of machine parts.
    • It involves the study of position, displacement, velocity, and acceleration of machine parts.

    Plane Motion

    • A body has plane motion if all its points move in planes parallel to some reference plane.
    • A body with plane motion will have only three degrees of freedom.
    • Plane motion can be of three types: translation, rotation, and combination of translation and rotation.
    • A machine part or a component of a mechanism is called a kinematic link or simply a link.
    • A link is assumed to be completely rigid and does not suffer any deformation.
    • Types of links are:
      • Binary link: connected to other links at two points.
      • Ternary link: connected to other links at three points.
      • Quaternary link: connected to other links at four points.

    Kinematic Chain

    • A mechanism is a kinematic chain with one of the links fixed.
    • A simple mechanism is a kinematic chain with four links.
    • A compound mechanism is a kinematic chain with more than four links.

    Kinematic Pair

    • Two links or elements of a machine that are in contact with each other are said to form a pair.
    • If the relative motion between them is completely or successfully constrained, the pair is known as a kinematic pair.
    • Classification of kinematic pairs:
      • Based on nature of contact: lower pair, higher pair.
      • Based on relative motion: sliding pair, turning pair, cylindrical pair, rolling pair, spherical pair, helical pair.
      • Based on nature of mechanical constraint: closed pair, unclosed or force-closed pair.

    Degrees of Freedom

    • Degrees of freedom (DOF) is the number of independent coordinates required to describe the position of a body in space.
    • In a kinematic pair, the links may lose some of the six degrees of freedom.
    • Kutzbach criterion for the mobility of a planar mechanism: F = 3(n-1) - 2l - h, where F is the degree of freedom, n is the number of links, l is the number of lower joints, and h is the number of higher pairs.

    Inversion of Mechanism

    • Inversion of a mechanism is obtained by fixing different links of the same kinematic chain.
    • Inversions of a four-bar chain: crank-rocker mechanism, double crank mechanism, double rocker mechanism.

    Coupler Curves

    • The link connecting the driving crank with the follower crank in a four-bar linkage is called the coupler.
    • During the motion of the mechanism, any point attached to the coupler generates some path with respect to the fixed link, which is called the coupler curve.

    Quick Return Motion Mechanisms

    • Quick return motion mechanisms are used in machine tools to give the reciprocating cutting tool a slow cutting stroke and a quick return stroke.
    • Examples of quick return motion mechanisms: Whitworth quick return motion mechanism, crank and slotted lever quick return motion mechanism.

    Velocity and Acceleration Analysis

    • Velocity analysis is important for determining the acceleration of points in the mechanisms.
    • Kinematics deals with the study of relative motion between the various parts of the machines.
    • Displacement, velocity, and acceleration are key concepts in kinematics.
    • Analysis can be carried out by graphical method as well as analytical method.

    Kinematic Synthesis

    • Kinematic synthesis, also known as mechanism synthesis, determines the size and configuration of mechanisms to achieve a desired performance.
    • It involves combining parts to form a whole, creating something new, and converting motion ideas into hardware.
    • Machines use chemical and electric power to manufacture, transport, and process items, and kinematic synthesis is used to design the elements that achieve required output forces and movement for a given input.

    Linkages

    • Linkages are the basic building blocks of all mechanisms.
    • They are made up of links and joints.
    • Links are rigid members with nodes (attachment points).
    • Joints are connections between two or more links that allow motion.
    • Joints can be classified in several ways, including:
      • Type of contact between elements (line, point, or surface)
      • Number of degrees of freedom allowed
      • Type of physical closure (force or form closed)
      • Number of links joined (order of the joint)

    Dynamic Force Analysis

    • D'Alembert's principle states that the reverse-effective forces and torques, and the external forces and torques on a body, together give statical equilibrium.
    • The principle can be used to derive the inertia force and inertia torque equations.
    • Inertia force (Fi) is proportional to the mass of the body and its acceleration.
    • Inertia torque (Ci) is a pure torque or couple.

    Equivalent Offset Inertia Force

    • The equivalent offset inertia force is a single force that accounts for both translational inertia and rotational inertia.
    • It is used for graphical plane force analysis.
    • The force is equivalent to the combination of a force and a torque.
    • The magnitude of the force is |maG|.
    • The direction of the force is opposite to that of acceleration a.
    • The perpendicular offset distance from the center of mass to the line of action of the force.

    Dynamic Analysis of Mechanisms

    • Dynamic analysis of a four-bar linkage illustrates the ideas presented in the chapter.
    • The analysis of a slider-crank mechanism demonstrates the importance of considering dynamic forces in design.

    Free Body Diagram

    • A free body diagram helps in understanding and solving static and dynamic problems involving forces.
    • It includes all forces acting on a given object without the other object in the system.
    • The diagram is used to represent forces by arrows in the direction of the force.
    • Examples of free body diagrams include a book on a table, a suspended block, and a block on a floor with an acting force.

    Kinematic Synthesis

    • Kinematic synthesis, also known as mechanism synthesis, determines the size and configuration of mechanisms to achieve a desired performance.
    • It involves combining parts to form a whole, creating something new, and converting motion ideas into hardware.
    • Machines use chemical and electric power to manufacture, transport, and process items, and kinematic synthesis is used to design the elements that achieve required output forces and movement for a given input.

    Linkages

    • Linkages are the basic building blocks of all mechanisms.
    • They are made up of links and joints.
    • Links are rigid members with nodes (attachment points).
    • Joints are connections between two or more links that allow motion.
    • Joints can be classified in several ways, including:
      • Type of contact between elements (line, point, or surface)
      • Number of degrees of freedom allowed
      • Type of physical closure (force or form closed)
      • Number of links joined (order of the joint)

    Dynamic Force Analysis

    • D'Alembert's principle states that the reverse-effective forces and torques, and the external forces and torques on a body, together give statical equilibrium.
    • The principle can be used to derive the inertia force and inertia torque equations.
    • Inertia force (Fi) is proportional to the mass of the body and its acceleration.
    • Inertia torque (Ci) is a pure torque or couple.

    Equivalent Offset Inertia Force

    • The equivalent offset inertia force is a single force that accounts for both translational inertia and rotational inertia.
    • It is used for graphical plane force analysis.
    • The force is equivalent to the combination of a force and a torque.
    • The magnitude of the force is |maG|.
    • The direction of the force is opposite to that of acceleration a.
    • The perpendicular offset distance from the center of mass to the line of action of the force.

    Dynamic Analysis of Mechanisms

    • Dynamic analysis of a four-bar linkage illustrates the ideas presented in the chapter.
    • The analysis of a slider-crank mechanism demonstrates the importance of considering dynamic forces in design.

    Free Body Diagram

    • A free body diagram helps in understanding and solving static and dynamic problems involving forces.
    • It includes all forces acting on a given object without the other object in the system.
    • The diagram is used to represent forces by arrows in the direction of the force.
    • Examples of free body diagrams include a book on a table, a suspended block, and a block on a floor with an acting force.

    Kinematic Synthesis

    • Kinematic synthesis, also known as mechanism synthesis, determines the size and configuration of mechanisms to achieve a desired performance.
    • It involves combining parts to form a whole, creating something new, and converting motion ideas into hardware.
    • Machines use chemical and electric power to manufacture, transport, and process items, and kinematic synthesis is used to design the elements that achieve required output forces and movement for a given input.

    Linkages

    • Linkages are the basic building blocks of all mechanisms.
    • They are made up of links and joints.
    • Links are rigid members with nodes (attachment points).
    • Joints are connections between two or more links that allow motion.
    • Joints can be classified in several ways, including:
      • Type of contact between elements (line, point, or surface)
      • Number of degrees of freedom allowed
      • Type of physical closure (force or form closed)
      • Number of links joined (order of the joint)

    Dynamic Force Analysis

    • D'Alembert's principle states that the reverse-effective forces and torques, and the external forces and torques on a body, together give statical equilibrium.
    • The principle can be used to derive the inertia force and inertia torque equations.
    • Inertia force (Fi) is proportional to the mass of the body and its acceleration.
    • Inertia torque (Ci) is a pure torque or couple.

    Equivalent Offset Inertia Force

    • The equivalent offset inertia force is a single force that accounts for both translational inertia and rotational inertia.
    • It is used for graphical plane force analysis.
    • The force is equivalent to the combination of a force and a torque.
    • The magnitude of the force is |maG|.
    • The direction of the force is opposite to that of acceleration a.
    • The perpendicular offset distance from the center of mass to the line of action of the force.

    Dynamic Analysis of Mechanisms

    • Dynamic analysis of a four-bar linkage illustrates the ideas presented in the chapter.
    • The analysis of a slider-crank mechanism demonstrates the importance of considering dynamic forces in design.

    Free Body Diagram

    • A free body diagram helps in understanding and solving static and dynamic problems involving forces.
    • It includes all forces acting on a given object without the other object in the system.
    • The diagram is used to represent forces by arrows in the direction of the force.
    • Examples of free body diagrams include a book on a table, a suspended block, and a block on a floor with an acting force.

    Cam and Follower

    • A cam is a mechanical device used to transmit motion to a follower by direct contact.
    • The cam and follower have line contact and constitute a higher pair.
    • The cam normally rotates at uniform speed, while the follower translates or oscillates according to the shape of the cam.

    Applications of Cams

    • Widely used in operating inlet and exhaust valves of Internal Combustion Engines
    • Used in automatic attachment of machineries, paper cutting machines, spinning and weaving textile machineries, and feed mechanism of automatic lathes

    Types of Followers

    • Based on surface in contact:
      • Knife edge follower
      • Roller follower
      • Flat faced follower
      • Spherical follower
    • Based on type of motion:
      • Oscillating follower
      • Translating follower

    Classification of Cams

    • Based on physical shape:
      • Disk or plate cam
      • Cylindrical cam
      • Translating cam

    Terms Used in Radial Cams

    • Pressure angle: the angle between the direction of the follower motion and a normal to the pitch curve
    • Base circle: the smallest circle that can be drawn to the cam profile
    • Trace point: the reference point on the follower used to generate the pitch curve
    • Pitch point: a point on the pitch curve having the maximum pressure angle
    • Pitch circle: a circle drawn from the centre of the cam through the pitch points
    • Pitch curve: the curve generated by the trace point as the follower moves relative to the cam
    • Prime circle: the smallest circle that can be drawn from the centre of the cam and tangent to the point

    Motion of the Follower

    • Cam follower systems are designed to achieve a desired oscillatory motion
    • Appropriate displacement patterns are to be selected for this purpose, before designing the cam surface
    • Some of the standard follower motions are:
      • Uniform velocity
      • Modified uniform velocity
      • Uniform acceleration and deceleration
      • Simple harmonic motion

    Displacement Diagrams

    • Displacement diagrams plot the motion of the follower against the angular displacement of the cam
    • From the displacement diagram, velocity and acceleration of the follower can also be plotted for different angular displacements of the cam
    • Displacement diagrams are basic requirements for the construction of cam profiles

    Cam and Follower

    • A cam is a mechanical device used to transmit motion to a follower by direct contact.
    • The cam and follower have line contact and constitute a higher pair.
    • The cam normally rotates at uniform speed, while the follower translates or oscillates according to the shape of the cam.

    Applications of Cams

    • Widely used in operating inlet and exhaust valves of Internal Combustion Engines
    • Used in automatic attachment of machineries, paper cutting machines, spinning and weaving textile machineries, and feed mechanism of automatic lathes

    Types of Followers

    • Based on surface in contact:
      • Knife edge follower
      • Roller follower
      • Flat faced follower
      • Spherical follower
    • Based on type of motion:
      • Oscillating follower
      • Translating follower

    Classification of Cams

    • Based on physical shape:
      • Disk or plate cam
      • Cylindrical cam
      • Translating cam

    Terms Used in Radial Cams

    • Pressure angle: the angle between the direction of the follower motion and a normal to the pitch curve
    • Base circle: the smallest circle that can be drawn to the cam profile
    • Trace point: the reference point on the follower used to generate the pitch curve
    • Pitch point: a point on the pitch curve having the maximum pressure angle
    • Pitch circle: a circle drawn from the centre of the cam through the pitch points
    • Pitch curve: the curve generated by the trace point as the follower moves relative to the cam
    • Prime circle: the smallest circle that can be drawn from the centre of the cam and tangent to the point

    Motion of the Follower

    • Cam follower systems are designed to achieve a desired oscillatory motion
    • Appropriate displacement patterns are to be selected for this purpose, before designing the cam surface
    • Some of the standard follower motions are:
      • Uniform velocity
      • Modified uniform velocity
      • Uniform acceleration and deceleration
      • Simple harmonic motion

    Displacement Diagrams

    • Displacement diagrams plot the motion of the follower against the angular displacement of the cam
    • From the displacement diagram, velocity and acceleration of the follower can also be plotted for different angular displacements of the cam
    • Displacement diagrams are basic requirements for the construction of cam profiles

    Cam and Follower

    • A cam is a mechanical device used to transmit motion to a follower by direct contact.
    • The cam and follower have line contact and constitute a higher pair.
    • The cam normally rotates at uniform speed, while the follower translates or oscillates according to the shape of the cam.

    Applications of Cams

    • Widely used in operating inlet and exhaust valves of Internal Combustion Engines
    • Used in automatic attachment of machineries, paper cutting machines, spinning and weaving textile machineries, and feed mechanism of automatic lathes

    Types of Followers

    • Based on surface in contact:
      • Knife edge follower
      • Roller follower
      • Flat faced follower
      • Spherical follower
    • Based on type of motion:
      • Oscillating follower
      • Translating follower

    Classification of Cams

    • Based on physical shape:
      • Disk or plate cam
      • Cylindrical cam
      • Translating cam

    Terms Used in Radial Cams

    • Pressure angle: the angle between the direction of the follower motion and a normal to the pitch curve
    • Base circle: the smallest circle that can be drawn to the cam profile
    • Trace point: the reference point on the follower used to generate the pitch curve
    • Pitch point: a point on the pitch curve having the maximum pressure angle
    • Pitch circle: a circle drawn from the centre of the cam through the pitch points
    • Pitch curve: the curve generated by the trace point as the follower moves relative to the cam
    • Prime circle: the smallest circle that can be drawn from the centre of the cam and tangent to the point

    Motion of the Follower

    • Cam follower systems are designed to achieve a desired oscillatory motion
    • Appropriate displacement patterns are to be selected for this purpose, before designing the cam surface
    • Some of the standard follower motions are:
      • Uniform velocity
      • Modified uniform velocity
      • Uniform acceleration and deceleration
      • Simple harmonic motion

    Displacement Diagrams

    • Displacement diagrams plot the motion of the follower against the angular displacement of the cam
    • From the displacement diagram, velocity and acceleration of the follower can also be plotted for different angular displacements of the cam
    • Displacement diagrams are basic requirements for the construction of cam profiles

    Belt Drives

    • A belt is a looped strip of flexible material used to mechanically link two or more rotating shafts, offering smooth transmission of power between shafts at a considerable distance.
    • Belt drives are used to efficiently transmit power or to track relative movement.
    • There are two types of belt drives: open belt drives and crossed belt drives.

    Open Belt Drives

    • Used to rotate the driven pulley in the same direction as the driving pulley.
    • Power transmission results in one side of the pulley being more tightened than the other side.
    • In horizontal drives, the tightened side is always kept on the lower side of two pulleys.

    Crossed Belt Drives

    • Used to rotate the driven pulley in the opposite direction of the driving pulley.
    • Higher wrap values enable more power transmission, but bending and wear of the belt are important concerns.

    Advantages of Belt Drives

    • Simple and economical
    • Don't require parallel shafts
    • Provided with overload and jam protection
    • Noise and vibration are damped out, increasing machinery life
    • Lubrication-free and require less maintenance cost
    • Highly efficient (up to 98%, usually 95%)
    • Economical when the distance between shafts is very large

    Disadvantages of Belt Drives

    • Angular velocity ratio is not necessarily constant or equal to the ratio of pulley diameters due to slipping and stretching
    • Heat buildup occurs
    • Speed is limited to usually 35 meters per second
    • Power transmission is limited to 370 kilowatts
    • Operating temperatures are usually restricted to -35 to 85°C
    • Adjustment of center distance or use of an idler pulley is necessary for wearing and stretching compensation

    Clutches

    • A mechanical device that engages and disengages power transmission from the driving shaft to the driven shaft
    • One shaft is connected to an engine or power unit, while the other shaft provides output power for the work

    Types of Clutches

    • Friction clutch
      • Single plate clutch
      • Multiplate clutch
        • Wet
        • Dry
    • Cone clutch
      • External
      • Internal
    • Centrifugal clutch
    • Semi-centrifugal clutch
    • Conical spring clutch or Diaphragm clutch
      • Tapered finger type
      • Crown spring type
    • Positive clutch
      • Dog clutch
    • Spline clutch
    • Hydraulic clutch
    • Electromagnetic clutch
    • Vacuum clutch
    • Overrunning clutch or freewheel unit

    Single Clutch Plate

    • One of the most commonly used types of clutches in light vehicles
    • Consists of a clutch plate, friction plate, pressure plate, flywheel, bearings, clutch spring, and not-bolts arrangement
    • The clutch plate is a thin metallic disc with friction surfaces on both sides
    • Working:
      • When the clutch pedal is pressed, the springs get compressed, and the pressure plate moves backward
      • The clutch plate becomes free between the pressure plate and flywheel, disengaging the clutch
      • The flywheel continues to rotate as long as the engine is running, and the clutch shaft speed reduces slowly and then stops rotating

    Multiplate Clutch

    • Uses multiple clutches to make frictional contact with a flywheel of the engine
    • Increases the capacity of the clutch to transmit torque
    • Working principle is the same as the single-plate clutch
    • Used in heavy commercial vehicles, racing cars, and motorcycles for transmitting high torque
    • Can be dry or wet, with wet clutches commonly used in automatic transmissions

    Cone Clutch

    • Uses two conical surfaces to transmit torque by friction
    • The engine shaft consists of a female cone and a male cone
    • The male cone is mounted on the splined clutch shaft to slide on it
    • Working:
      • When the clutch is engaged, the friction surfaces of the male cone are in contact with the female cone
      • When the clutch pedal is pressed, the male cone slides towards the spring force, and the clutch is disengaged

    Centrifugal Clutch

    • Uses centrifugal force to operate the clutch instead of spring force
    • Consists of weights pivoted at a point, which fly off due to centrifugal force when the engine speed increases
    • The bell crank levels press the plate, which ultimately presses the clutch plate on the flywheel against the spring
    • No clutch pedal is required to operate the clutch

    Belt Drives

    • A belt is a looped strip of flexible material used to mechanically link two or more rotating shafts, offering smooth transmission of power between shafts at a considerable distance.
    • Belt drives are used to efficiently transmit power or to track relative movement.
    • There are two types of belt drives: open belt drives and crossed belt drives.

    Open Belt Drives

    • Used to rotate the driven pulley in the same direction as the driving pulley.
    • Power transmission results in one side of the pulley being more tightened than the other side.
    • In horizontal drives, the tightened side is always kept on the lower side of two pulleys.

    Crossed Belt Drives

    • Used to rotate the driven pulley in the opposite direction of the driving pulley.
    • Higher wrap values enable more power transmission, but bending and wear of the belt are important concerns.

    Advantages of Belt Drives

    • Simple and economical
    • Don't require parallel shafts
    • Provided with overload and jam protection
    • Noise and vibration are damped out, increasing machinery life
    • Lubrication-free and require less maintenance cost
    • Highly efficient (up to 98%, usually 95%)
    • Economical when the distance between shafts is very large

    Disadvantages of Belt Drives

    • Angular velocity ratio is not necessarily constant or equal to the ratio of pulley diameters due to slipping and stretching
    • Heat buildup occurs
    • Speed is limited to usually 35 meters per second
    • Power transmission is limited to 370 kilowatts
    • Operating temperatures are usually restricted to -35 to 85°C
    • Adjustment of center distance or use of an idler pulley is necessary for wearing and stretching compensation

    Clutches

    • A mechanical device that engages and disengages power transmission from the driving shaft to the driven shaft
    • One shaft is connected to an engine or power unit, while the other shaft provides output power for the work

    Types of Clutches

    • Friction clutch
      • Single plate clutch
      • Multiplate clutch
        • Wet
        • Dry
    • Cone clutch
      • External
      • Internal
    • Centrifugal clutch
    • Semi-centrifugal clutch
    • Conical spring clutch or Diaphragm clutch
      • Tapered finger type
      • Crown spring type
    • Positive clutch
      • Dog clutch
    • Spline clutch
    • Hydraulic clutch
    • Electromagnetic clutch
    • Vacuum clutch
    • Overrunning clutch or freewheel unit

    Single Clutch Plate

    • One of the most commonly used types of clutches in light vehicles
    • Consists of a clutch plate, friction plate, pressure plate, flywheel, bearings, clutch spring, and not-bolts arrangement
    • The clutch plate is a thin metallic disc with friction surfaces on both sides
    • Working:
      • When the clutch pedal is pressed, the springs get compressed, and the pressure plate moves backward
      • The clutch plate becomes free between the pressure plate and flywheel, disengaging the clutch
      • The flywheel continues to rotate as long as the engine is running, and the clutch shaft speed reduces slowly and then stops rotating

    Multiplate Clutch

    • Uses multiple clutches to make frictional contact with a flywheel of the engine
    • Increases the capacity of the clutch to transmit torque
    • Working principle is the same as the single-plate clutch
    • Used in heavy commercial vehicles, racing cars, and motorcycles for transmitting high torque
    • Can be dry or wet, with wet clutches commonly used in automatic transmissions

    Cone Clutch

    • Uses two conical surfaces to transmit torque by friction
    • The engine shaft consists of a female cone and a male cone
    • The male cone is mounted on the splined clutch shaft to slide on it
    • Working:
      • When the clutch is engaged, the friction surfaces of the male cone are in contact with the female cone
      • When the clutch pedal is pressed, the male cone slides towards the spring force, and the clutch is disengaged

    Centrifugal Clutch

    • Uses centrifugal force to operate the clutch instead of spring force
    • Consists of weights pivoted at a point, which fly off due to centrifugal force when the engine speed increases
    • The bell crank levels press the plate, which ultimately presses the clutch plate on the flywheel against the spring
    • No clutch pedal is required to operate the clutch

    Belt Drives

    • A belt is a looped strip of flexible material used to mechanically link two or more rotating shafts.
    • Belt drives offer smooth transmission of power between shafts at a considerable distance.
    • Types of belt drives:
      • Open belt drive: used to rotate the driven pulley in the same direction of driving pulley.
      • Crossed belt drive: used to rotate driven pulley in the opposite direction of driving pulley.

    Advantages of Belt Drives

    • Simple and economical.
    • No need for parallel shafts.
    • Provides overload and jam protection.
    • Noise and vibration are damped out.
    • Machinery life is increased due to shock-absorption of load fluctuations.
    • Lubrication-free.
    • Low maintenance cost.
    • Highly efficient (up to 98%).
    • Economical when the distance between shafts is very large.

    Disadvantages of Belt Drives

    • Angular velocity ratio is not necessarily constant or equal to the ratio of pulley diameters due to slipping and stretching.
    • Heat buildup occurs.
    • Speed is limited to usually 35 meters per second.
    • Power transmission is limited to 370 kilowatts.
    • Operating temperatures are usually restricted to -35 to 85°C.
    • Some adjustment of center distance or use of an idler pulley is necessary for wearing and stretching of belt drive compensation.

    Clutches

    • A clutch is a mechanical device that specifically engages and disengages power transmission from the driving shaft to the driven shaft.
    • Types of clutches:
      • Friction clutch
      • Single plate clutch
      • Multiplate clutch
      • Cone clutch
      • Centrifugal clutch
      • Semi-centrifugal clutch
      • Conical spring clutch or Diaphragm clutch
      • Positive clutch
      • Spline clutch
      • Hydraulic clutch
      • Electromagnetic clutch
      • Vacuum clutch
      • Overrunning clutch or freewheel unit

    Single Plate Clutch

    • Used in most modern light vehicles.
    • Consists of a clutch plate, friction plate, pressure plate, flywheel, bearings, clutch spring, and not-bolts arrangement.
    • The clutch plate is a thin metallic disc with both side friction surfaces.
    • The pressure plate is bolted to the flywheel through a clutch spring, which provides the axial force to keep the clutch engaged.

    Working of Single Plate Clutch

    • When the clutch pedal is pressed, the pressure plate moves backward, and the clutch plate becomes free between the pressure plate and flywheel.
    • This disengages the clutch and allows gear shifting.
    • When the clutch pedal is released, the pressure plate returns to its original position, and the clutch is again engaged.

    Multiplate Clutch

    • Used in heavy commercial vehicles, racing cars, and motorcycles for transmitting high torque.
    • Consists of multiple clutches to make frictional contact with a flywheel of the engine.
    • The increased number of friction surfaces increases the capacity of the clutch to transmit torque.
    • Can be either dry or wet.

    Cone Clutch

    • Uses two conical surfaces to transmit torque by friction.
    • The engine shaft consists of a female cone and a male cone mounted on the splined clutch shaft.
    • The advantage of using a cone clutch is that the normal force acting on the friction surface is greater than the axial force.

    Centrifugal Clutch

    • Uses centrifugal force to keep the clutch in the engaged position.
    • No clutch pedal is required to operate the clutch.
    • The clutch is operated automatically depending on the engine speed.
    • Makes it easy for the driver to stop the vehicle in any gear without stalling the engine.

    Gears and Gear Teeth

    • Gears transmit motion by engaging teeth, which act as small levers, and are highly efficient (~95%) due to rolling contact between teeth.
    • Gear teeth allow positive engagement, enabling high forces to be transmitted while minimizing friction.

    Classification of Toothed Wheels

    • Gears can be classified according to the relative position of the axes of revolution:
      • Connecting parallel shafts (e.g., spur gears, helical gears)
      • Connecting intersecting shafts (e.g., bevel gears)
      • Neither parallel nor intersecting shafts (e.g., helical gears, worm and worm gear)

    Types of Gears

    • Spur gears:
      • Most common type of gear
      • Teeth are perpendicular to the face of the gear
      • Limited to parallel shaft applications
      • Can be noisy and stressful on gear teeth
    • Helical gears:
      • Teeth are cut at an angle to the face of the gear
      • Operate smoothly and quietly
      • Can be used for parallel or perpendicular shaft applications
      • Greater surface contact allows for higher loads
    • Bevel gears:
      • Used to change direction of rotation
      • Teeth can be straight, spiral, or hypoid
      • Can be designed for various angles
    • Worm and worm gear:
      • Used for large gear reductions (e.g., 20:1 or greater)
      • Worm can easily turn the gear, but not vice versa, due to friction
      • Common in conveyor systems and high-performance vehicles

    Terms Used in Gears

    • Addendum: Radial distance between pitch circle and top of teeth
    • Dedendum: Radial distance between bottom of tooth and pitch circle
    • Base Circle: Circle from which involute curve is generated
    • Center Distance: Distance between centers of two gears
    • Circular Pitch: Millimeters of pitch circle circumference per tooth
    • Contact Ratio: Ratio of length of arc of action to circular pitch

    Fundamental Law of Gear-Tooth Action

    • A common normal to the tooth profiles at their point of contact must pass through a fixed point on the line of centers called the pitch point.
    • Velocity ratio is equal to the inverse ratio of the diameters of pitch circles.

    Conjugate Profiles

    • Tooth profiles that satisfy the fundamental law of gear-tooth action
    • Involute and cycloidal profiles are commonly used
    • Involute profile is easy to manufacture and allows for varying center distance without changing velocity ratio

    Generation of Involute Curve

    • Involute curve is the path traced by a point on a line as it rolls without slipping on the circumference of a circle

    • Can be defined as a path traced by the end of a string as it is unwrapped from a circle### Interference in Gears

    • Interference between two teeth can be prevented if the point of contact is always on the involute profiles and if the addendum circles of the two mating gears cut the common tangent to the base circles at the points of tangency.

    • To avoid interference, the following can be done:

      • Reduce the height of the teeth
      • Use undercut of the radial flank of the pinion
      • Increase the centre distance, which leads to an increase in pressure angle
      • Use a minimum number of teeth on the pinion (t) and wheel (T) to avoid interference

    Backlash

    • Backlash is the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth
    • Backlash is the error in motion that occurs when gears change direction
    • The term "backlash" can also refer to the size of the gap

    Practice Problem

    • Given a module of 8 mm, a pressure angle of 20°, a larger gear with 57 teeth, and a pinion with 23 teeth, and an addendum of 1 module (8 mm)
    • Pitch circle radius of the pinion (r) = mt = 92 mm
    • Pitch circle radius of the gear (R) = mT = 228 mm
    • Addendum circle radius of the pinion (ra) = r + addendum = 100 mm
    • Addendum circle radius of the gear (RA) = R + addendum = 236 mm
    • Length of path of contact (KL) = 39.76 mm
    • Length of arc of contact = 42.31 mm
    • Number of pairs of teeth in contact = (length of arc of contact) / (circular pitch)

    Gears and Gear Teeth

    • Gears transmit motion by engaging teeth, which act as small levers, and are highly efficient (~95%) due to rolling contact between teeth.
    • Gear teeth allow positive engagement, enabling high forces to be transmitted while minimizing friction.

    Classification of Toothed Wheels

    • Gears can be classified according to the relative position of the axes of revolution:
      • Connecting parallel shafts (e.g., spur gears, helical gears)
      • Connecting intersecting shafts (e.g., bevel gears)
      • Neither parallel nor intersecting shafts (e.g., helical gears, worm and worm gear)

    Types of Gears

    • Spur gears:
      • Most common type of gear
      • Teeth are perpendicular to the face of the gear
      • Limited to parallel shaft applications
      • Can be noisy and stressful on gear teeth
    • Helical gears:
      • Teeth are cut at an angle to the face of the gear
      • Operate smoothly and quietly
      • Can be used for parallel or perpendicular shaft applications
      • Greater surface contact allows for higher loads
    • Bevel gears:
      • Used to change direction of rotation
      • Teeth can be straight, spiral, or hypoid
      • Can be designed for various angles
    • Worm and worm gear:
      • Used for large gear reductions (e.g., 20:1 or greater)
      • Worm can easily turn the gear, but not vice versa, due to friction
      • Common in conveyor systems and high-performance vehicles

    Terms Used in Gears

    • Addendum: Radial distance between pitch circle and top of teeth
    • Dedendum: Radial distance between bottom of tooth and pitch circle
    • Base Circle: Circle from which involute curve is generated
    • Center Distance: Distance between centers of two gears
    • Circular Pitch: Millimeters of pitch circle circumference per tooth
    • Contact Ratio: Ratio of length of arc of action to circular pitch

    Fundamental Law of Gear-Tooth Action

    • A common normal to the tooth profiles at their point of contact must pass through a fixed point on the line of centers called the pitch point.
    • Velocity ratio is equal to the inverse ratio of the diameters of pitch circles.

    Conjugate Profiles

    • Tooth profiles that satisfy the fundamental law of gear-tooth action
    • Involute and cycloidal profiles are commonly used
    • Involute profile is easy to manufacture and allows for varying center distance without changing velocity ratio

    Generation of Involute Curve

    • Involute curve is the path traced by a point on a line as it rolls without slipping on the circumference of a circle

    • Can be defined as a path traced by the end of a string as it is unwrapped from a circle### Interference in Gears

    • Interference between two teeth can be prevented if the point of contact is always on the involute profiles and if the addendum circles of the two mating gears cut the common tangent to the base circles at the points of tangency.

    • To avoid interference, the following can be done:

      • Reduce the height of the teeth
      • Use undercut of the radial flank of the pinion
      • Increase the centre distance, which leads to an increase in pressure angle
      • Use a minimum number of teeth on the pinion (t) and wheel (T) to avoid interference

    Backlash

    • Backlash is the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth
    • Backlash is the error in motion that occurs when gears change direction
    • The term "backlash" can also refer to the size of the gap

    Practice Problem

    • Given a module of 8 mm, a pressure angle of 20°, a larger gear with 57 teeth, and a pinion with 23 teeth, and an addendum of 1 module (8 mm)
    • Pitch circle radius of the pinion (r) = mt = 92 mm
    • Pitch circle radius of the gear (R) = mT = 228 mm
    • Addendum circle radius of the pinion (ra) = r + addendum = 100 mm
    • Addendum circle radius of the gear (RA) = R + addendum = 236 mm
    • Length of path of contact (KL) = 39.76 mm
    • Length of arc of contact = 42.31 mm
    • Number of pairs of teeth in contact = (length of arc of contact) / (circular pitch)

    Gears and Gear Teeth

    • Gears transmit motion by engaging teeth, which act as small levers, and are highly efficient (~95%) due to rolling contact between teeth.
    • Gear teeth allow positive engagement, enabling high forces to be transmitted while minimizing friction.

    Classification of Toothed Wheels

    • Gears can be classified according to the relative position of the axes of revolution:
      • Connecting parallel shafts (e.g., spur gears, helical gears)
      • Connecting intersecting shafts (e.g., bevel gears)
      • Neither parallel nor intersecting shafts (e.g., helical gears, worm and worm gear)

    Types of Gears

    • Spur gears:
      • Most common type of gear
      • Teeth are perpendicular to the face of the gear
      • Limited to parallel shaft applications
      • Can be noisy and stressful on gear teeth
    • Helical gears:
      • Teeth are cut at an angle to the face of the gear
      • Operate smoothly and quietly
      • Can be used for parallel or perpendicular shaft applications
      • Greater surface contact allows for higher loads
    • Bevel gears:
      • Used to change direction of rotation
      • Teeth can be straight, spiral, or hypoid
      • Can be designed for various angles
    • Worm and worm gear:
      • Used for large gear reductions (e.g., 20:1 or greater)
      • Worm can easily turn the gear, but not vice versa, due to friction
      • Common in conveyor systems and high-performance vehicles

    Terms Used in Gears

    • Addendum: Radial distance between pitch circle and top of teeth
    • Dedendum: Radial distance between bottom of tooth and pitch circle
    • Base Circle: Circle from which involute curve is generated
    • Center Distance: Distance between centers of two gears
    • Circular Pitch: Millimeters of pitch circle circumference per tooth
    • Contact Ratio: Ratio of length of arc of action to circular pitch

    Fundamental Law of Gear-Tooth Action

    • A common normal to the tooth profiles at their point of contact must pass through a fixed point on the line of centers called the pitch point.
    • Velocity ratio is equal to the inverse ratio of the diameters of pitch circles.

    Conjugate Profiles

    • Tooth profiles that satisfy the fundamental law of gear-tooth action
    • Involute and cycloidal profiles are commonly used
    • Involute profile is easy to manufacture and allows for varying center distance without changing velocity ratio

    Generation of Involute Curve

    • Involute curve is the path traced by a point on a line as it rolls without slipping on the circumference of a circle

    • Can be defined as a path traced by the end of a string as it is unwrapped from a circle### Interference in Gears

    • Interference between two teeth can be prevented if the point of contact is always on the involute profiles and if the addendum circles of the two mating gears cut the common tangent to the base circles at the points of tangency.

    • To avoid interference, the following can be done:

      • Reduce the height of the teeth
      • Use undercut of the radial flank of the pinion
      • Increase the centre distance, which leads to an increase in pressure angle
      • Use a minimum number of teeth on the pinion (t) and wheel (T) to avoid interference

    Backlash

    • Backlash is the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth
    • Backlash is the error in motion that occurs when gears change direction
    • The term "backlash" can also refer to the size of the gap

    Practice Problem

    • Given a module of 8 mm, a pressure angle of 20°, a larger gear with 57 teeth, and a pinion with 23 teeth, and an addendum of 1 module (8 mm)
    • Pitch circle radius of the pinion (r) = mt = 92 mm
    • Pitch circle radius of the gear (R) = mT = 228 mm
    • Addendum circle radius of the pinion (ra) = r + addendum = 100 mm
    • Addendum circle radius of the gear (RA) = R + addendum = 236 mm
    • Length of path of contact (KL) = 39.76 mm
    • Length of arc of contact = 42.31 mm
    • Number of pairs of teeth in contact = (length of arc of contact) / (circular pitch)

    Gears and Gear Teeth

    • Gears transmit motion by engaging teeth, which act as small levers, and are highly efficient (~95%) due to rolling contact between teeth.
    • Gear teeth allow positive engagement, enabling high forces to be transmitted while minimizing friction.

    Classification of Toothed Wheels

    • Gears can be classified according to the relative position of the axes of revolution:
      • Connecting parallel shafts (e.g., spur gears, helical gears)
      • Connecting intersecting shafts (e.g., bevel gears)
      • Neither parallel nor intersecting shafts (e.g., helical gears, worm and worm gear)

    Types of Gears

    • Spur gears:
      • Most common type of gear
      • Teeth are perpendicular to the face of the gear
      • Limited to parallel shaft applications
      • Can be noisy and stressful on gear teeth
    • Helical gears:
      • Teeth are cut at an angle to the face of the gear
      • Operate smoothly and quietly
      • Can be used for parallel or perpendicular shaft applications
      • Greater surface contact allows for higher loads
    • Bevel gears:
      • Used to change direction of rotation
      • Teeth can be straight, spiral, or hypoid
      • Can be designed for various angles
    • Worm and worm gear:
      • Used for large gear reductions (e.g., 20:1 or greater)
      • Worm can easily turn the gear, but not vice versa, due to friction
      • Common in conveyor systems and high-performance vehicles

    Terms Used in Gears

    • Addendum: Radial distance between pitch circle and top of teeth
    • Dedendum: Radial distance between bottom of tooth and pitch circle
    • Base Circle: Circle from which involute curve is generated
    • Center Distance: Distance between centers of two gears
    • Circular Pitch: Millimeters of pitch circle circumference per tooth
    • Contact Ratio: Ratio of length of arc of action to circular pitch

    Fundamental Law of Gear-Tooth Action

    • A common normal to the tooth profiles at their point of contact must pass through a fixed point on the line of centers called the pitch point.
    • Velocity ratio is equal to the inverse ratio of the diameters of pitch circles.

    Conjugate Profiles

    • Tooth profiles that satisfy the fundamental law of gear-tooth action
    • Involute and cycloidal profiles are commonly used
    • Involute profile is easy to manufacture and allows for varying center distance without changing velocity ratio

    Generation of Involute Curve

    • Involute curve is the path traced by a point on a line as it rolls without slipping on the circumference of a circle

    • Can be defined as a path traced by the end of a string as it is unwrapped from a circle### Interference in Gears

    • Interference between two teeth can be prevented if the point of contact is always on the involute profiles and if the addendum circles of the two mating gears cut the common tangent to the base circles at the points of tangency.

    • To avoid interference, the following can be done:

      • Reduce the height of the teeth
      • Use undercut of the radial flank of the pinion
      • Increase the centre distance, which leads to an increase in pressure angle
      • Use a minimum number of teeth on the pinion (t) and wheel (T) to avoid interference

    Backlash

    • Backlash is the gap between the non-drive face of the pinion tooth and the adjacent wheel tooth
    • Backlash is the error in motion that occurs when gears change direction
    • The term "backlash" can also refer to the size of the gap

    Practice Problem

    • Given a module of 8 mm, a pressure angle of 20°, a larger gear with 57 teeth, and a pinion with 23 teeth, and an addendum of 1 module (8 mm)
    • Pitch circle radius of the pinion (r) = mt = 92 mm
    • Pitch circle radius of the gear (R) = mT = 228 mm
    • Addendum circle radius of the pinion (ra) = r + addendum = 100 mm
    • Addendum circle radius of the gear (RA) = R + addendum = 236 mm
    • Length of path of contact (KL) = 39.76 mm
    • Length of arc of contact = 42.31 mm
    • Number of pairs of teeth in contact = (length of arc of contact) / (circular pitch)

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