Automotive Steering Systems Quiz

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Questions and Answers

What is the primary function of a steering gear in a vehicle?

To adjust the tire pressure

To control brake fluid levels

To transform and amplify the driver's steering input (correct)

To regulate engine temperature

What type of steering gear uses a worm alongside a wheel sector?

Worm and roller type

Worm and worm-sector type (correct)

Worm and nut type

Recirculating steel balls type

How many complete rotations of the steering wheel correspond to one rotation in the output of the steering gear?

12.5

5.2

10.0

18.2 (correct)

What common type of joint connects the tie rod and steering arms?

Ball joint Signup and view all the answers

Which vehicle mentioned utilizes a recirculating steel balls type steering gear?

Tata 1210 Signup and view all the answers

What happens to gear B when gear A is imparted a rotation while the arm is locked?

Gear B rotates in the same direction. Signup and view all the answers

What is the function of the internal gear in an epicyclic gearbox?

To interact with the sun and planet gears. Signup and view all the answers

How is gear reduction achieved in an epicyclic gearbox?

By holding the sun gear stationary while driving the ring gear. Signup and view all the answers

What condition must be met to obtain direct drive in a planetary gear set?

Both the sun gear and ring gear must be locked together. Signup and view all the answers

Which component is responsible for changing the input power flow to create a reverse rotation?

The pinion carrier must be held stationary. Signup and view all the answers

Which statement is true regarding the planetary gear set?

It ensures that all parts can act as a driver or driven member. Signup and view all the answers

What is the effect of locking larger gear A in an epicyclic gear train?

It yields a specific gear ratio. Signup and view all the answers

What is the purpose of the king-pin or steering axis inclination?

To keep the front wheels pointing forward and to return to a straight position after a turn Signup and view all the answers

What is the ideal range for the king-pin angle in vehicles?

3° to 9° Signup and view all the answers

How does caster relate to king-pin inclination?

It is the angle formed between the vertical line and the inherent king-pin inclination Signup and view all the answers

What happens if the king-pin angle is larger than the required values?

Steering the vehicle will become difficult Signup and view all the answers

What is the primary function of a front wheel steering system?

To steer the front wheels, which then guide the rear wheels Signup and view all the answers

Which type of caster angle is preferred in modern automobiles?

Negative caster Signup and view all the answers

What is a notable advantage of an all-wheel steering system over a front wheel steering system?

All wheels can be steered, enhancing maneuverability Signup and view all the answers

What is the 'included angle' in relation to vehicle suspension?

The sum of the camber angle and king-pin angle Signup and view all the answers

What is the role of caster in vehicle dynamics?

To provide directional stability and minimize wheel wander Signup and view all the answers

Which of the following is NOT a desired requirement in a good steering system?

Ability to steer only the front wheels Signup and view all the answers

What type of structural member does a rigid axle beam primarily consist of?

An I-section in the central region and circular section at the ends Signup and view all the answers

What can result from unequal king-pin angles on each wheel?

The vehicle will drift towards the side with the larger angle Signup and view all the answers

What effect does the provision of spring seats on a rigid axle beam have?

Supports the vehicle to minimize unsprung weight Signup and view all the answers

What is likely to occur with a negative caster angle?

Improvement in directional stability Signup and view all the answers

What is a potential downside of having a king-pin angle of 12° on a vehicle?

Higher risk of steering difficulty Signup and view all the answers

Why is power steering increasingly being used in vehicles?

It reduces the effort needed to steer the vehicle Signup and view all the answers

What is the role of king pins in a front axle?

To allow swiveling of the stub axles Signup and view all the answers

Which factor does NOT affect the performance of a steering system?

Type of fuel used in the vehicle Signup and view all the answers

In what manner do stub axles function within the front axle system?

They hold the front wheels and obey steering commands Signup and view all the answers

What is the typical range of the angle formed in the vertical plane when viewing a vehicle from the front?

5° to 12° Signup and view all the answers

What does correct steering ensure in a vehicle?

Wheels undergo pure rolling motion under all conditions Signup and view all the answers

What is the instantaneous center of rotation for a vehicle?

Point where the stub axles of front wheels intersect Signup and view all the answers

When a vehicle is negotiating a right turn, how do the inner and outer front wheels turn?

Inner front wheel turns by a larger angle Signup and view all the answers

How many correct steering positions can a vehicle have?

Three Signup and view all the answers

What factors determine the values of the angles θ and Φ in steering?

Dimensions L and W of the vehicle Signup and view all the answers

What happens to the linkage CEFA when steering is desired to the right?

It takes on a new configuration Signup and view all the answers

Which condition allows for pure rolling without slipping in a vehicle's wheels?

When the axes of the stub axles intersect on the common axis of the rear wheels Signup and view all the answers

What is required for correct steering when turning a vehicle?

Different angular values for inner and outer front wheels Signup and view all the answers

What configuration is crucial for maintaining correct steering geometry?

The linkages must form triangles with specific measurements Signup and view all the answers

Study Notes

Automotive Engineering Course after 1st Term

Topics covered for Gear
- Description of sliding mesh and constant mesh gearboxes
- Synchro-mesh gearboxes
- Semi-automatic transmissions
- Final drive and differentials, rear axles, and overdrive

Introduction to Gear Box (Transmission)

Gearbox acts according to running conditions
- Reduces engine speed and increases torque when power is needed
- Transmits high speed and low torque to wheels when high speed is desired
- Reverses vehicle by meshing gears
Gears used are helical gears
- Helical teeth are set at an angle to the gear centreline
- Wiping action improves contact and lubrication

Gear Ratio

Gear ratio is determined by the number of teeth on the two gears
- Gear ratio = (Number of teeth on Driven gear) / (Number of teeth on Driving gear)
- If smaller gear (with 15 teeth) drives larger gear (with 30 teeth), the ratio is 2:1 (2 to 1)
- A 15-tooth gear driving a 45-tooth gear results in a 3:1 (3 to 1) gear ratio
Typical gear box ratios in a small car with a four-speed gearbox
- 3.5:1 (3.5 to 1) for first gear
- 2:1 (2 to 1) for second gear
- 1.4:1 (1.4 to 1) for third gear
- 1:1 (1 to 1) for top gear
These ratios are multiplied by the axle ratio (4:1) to determine the corresponding ratios between engine speed and road wheel speed
Power available from the engine is directly proportional to the engine torque (T) and the gear box ratio (G)

Torque and Gear Ratio

When smaller gear drives larger gear, the gear ratio is 2:1, but the torque ratio is 1:2
Larger gear has twice the torque of smaller gear
Speed reduction in gear systems increases the torque

Types of Gear Boxes

Selective type:
- Sliding mesh
- Constant mesh
- Synchromesh
Progressive type
Epicyclic or planetary type

Selective Type Gear Boxes

Any speed can be selected from the neutral position
Neutral position needed before selecting forward or reverse
Advantages: simple construction, relatively trouble-free, light and small, low production costs
Disadvantages: gear ratios in steps (3 to 5 steps), noisy operation

Sliding Mesh Gear Box

Gears on splined main shaft move left or right to mesh with appropriate gears on the lay shaft for different speeds
Gears mesh by sliding or crashing onto each other
Also known as crash-type gearbox

Constant Mesh Gear Box

All gears are in constant mesh with each other
Helical gears for easier gear changing.
Main shaft is splined and gears are free
Two dog clutches provided on the main shaft

Synchro Mesh Gear Box

Sliding synchronizing units to replace sliding dog clutches
Synchronizing unit synchronizes driving and driven shafts before engagement
Arrangements of power flow for gears remain the same as in constant mesh gearbox

Synchromesh Gear Devices

Two gears brought into frictional contact to equalize speed before engagement
Two types: pin type and synchronizer ring type

Conical Surfaces in Synchromesh

Cone 1 part of collar; Cone 2 part of gear wheel
Cones revolve at different speeds
Friction slows or speeds up gear wheel, then both revolve at the same speed

Synchromesh Figure

Collar and gear wheel rotate at the same speed
Spring-loaded outer ring of collar pushed forward
Dogs slide smoothly into mesh without clashing

Gearbox Components:

Sun gear, planet gears, planet carrier, arm.
Simplest epicyclic gear train provides three different gear ratios when arm is locked, or the larger gear or the smaller pinion is locked.

Overdrive

Interposed between transmission (gearbox) and propeller shaft
Enables propeller shaft to turn faster than the transmission main shaft
Called overdrive because it provides a higher speed ratio than the high-speed ratio
Permits engine operation at about 70% of propeller shaft speed in high-speed ranges
Suited for high-powered cars with three-speed gearboxes
Provides super-top gear
Ratio of engine crankshaft speed /road speed equal to 1 in top gear and less than 1 in super-top gear

Advantages of Overdrive

Attain cruising speed on highways and expressways at low engine speeds
Reduced engine part wear due to low speeds
Decreased vibrations and noise
Lesser frictional losses in the engine
Fuel saving due to lower engine speeds

Differential

Mechanism of epicyclic gear train, located between final drive and rear axles
Purposes: avoid rear wheel skidding during turning; reduce inner wheel speed and increase outer wheel speed while negotiating curves; maintain equal wheel speeds when moving straight

Differential: Necessity of Differential

Rear wheels roll-down the road at equal speeds when in straight motion
Outer wheels cover a longer distance than inner wheels during turning
Without a differential, outer wheels would skid during turns

Differential: Consequence of No Differential

Outer wheels skid; inner wheels exert excessive pressure on road surface

Differential Construction and Working

Consists of bevel pinion & crown wheel; cage; two sun gears; two planet pinions, cross-pin or spider
Sun gears always in mesh with planet pinions
Half shaft (rear axle) is splined to allow movement in sun gear
Outer half-shaft ends connected to wheel hub
Crown wheel rotates freely on bush mounted over one half-shaft

Steering Systems

Assembly of linkages to control the vehicle's direction
Driver input to steering wheel results in lateral movement of wheels
Efficient control achieved with pure rolling motion
Steering systems: Front-wheel or all-wheel
Front-wheel steering systems are popular; power steering provides assisted steering

Front Axle

Holds front wheels, allowing their rotation and obeying steering commands
Rigid axle beam type (stationary): Used to connect stub axles and sustain bending/torsion; I-section for bending resistance; circular ends for torsion resistance
Stub axle type (intermediate): Short shaft between road wheel and front (dead) axle; connected to axle beam by kingpins

Steering Gear

Transforms steering wheel rotary motion into reciprocating drag link motion
Multiplies small steering wheel effort to greater force on the drag link Different types: worm and worm wheel; worm and sector; recircuting steel balls

Steering Gear Ratio and Overall Steering Ratio

Steering gear ratio (SGR): Ratio of steering wheel turn angle to steering gear cross-shaft turn angle -Lower value = faster steering, useful for small, fast vehicles
Overall steering ratio (OSR): Includes the mechanical advantage of linkages too, making the ratio slightly larger than SGR, useful for cars with higher speed.

Wheel Alignment

Setting front wheels and steering mechanism for easy turn control, minimizing tyre wear and maintaining straight-line stability
Toe-in / Toe-out: Front wheels set closer at the front, or further apart than their rear, in the stationary state
Camber: Angular tilt of the wheel
Caster: Tilting of the kingpin from the vertical axis

Ackermann's Steering Mechanism

Mechanism design to ensure that wheel turn angles are different for inner and outer wheels during cornering
Equal angles of inclination for two links connecting the steering arms are achieved for correct cornering.

Layout of Steering System

Key components and linkages of a steering system in a car

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Description

Test your knowledge on the key components and functions of automotive steering systems. This quiz includes questions about steering gears, joints, and vehicle types that utilize specific steering mechanisms. Perfect for students and enthusiasts of automotive engineering.