Understanding Complex Material Analysis

Bearings

• Two basic types of bearings are used: friction and anti-friction bearings
• Friction bearings have a sliding contact between a shaft and the bearing
• Friction bearings use a special low-friction material lining a rigid housing
• Anti-friction bearings have a rolling contact between the shaft and bearing, using balls, needles or rollers
• Bearing housings are the outer casing
• Common materials for housings are cast iron, cast steel and fabricated steel
• Bearing dimensions are important for installation and alignment
• Bearing styles are chosen based on load, speed and direction of pull
• Solid bearings are used for low speed and load
• Split bearings differ in their housings

Bearing Housings

• Housings are sometimes called pillow blocks
• Parts of a friction bearing include: base, base bolt slots, cap, and cap bolt holes
• Common bearing housing sizes are fractional, not decimal
• Bearing size, design and service weight from the same supplier will usually have the same shaft centre dimension.

Styles of Bearings

• Types of flat bearings include solid and split bearings
• Solid bearings are frequently mounted in an inverted position and must be slid on or off the shaft
• Split bearing designs vary depending on manufacturer
• The choice of a bearing depends on load, rotational speed, and direction of pull
• Angle bearings are used when the load is applied parallel to or at a slight angle to the horizontal or when the bearing is mounted on a vertical support

Liner Materials

• Common metallic liner materials are babbitt, brass, bronze, and aluminum
• Common non-metallic liner materials are nylon, polyurethane, and phenol laminates
• Babbitt is a common anti-friction lining material for bearings
• Babbitt melts at a temperature of about 288°C (550°F)

Liner Materials (cont)

• Babbitt alloys commonly contain tin, copper, antimony and lead, with varying proportions
• Using mandrels to pour babbitt, which are short smooth pieces of shaft of the required diameter to hold the bearing securely in position during pouring

Bearing Installation and Removal

• Bearings are installed square on the shaft
• Shaft and housing checks should include diameter, roundness, deflection, surface damage, and cracks before installation
• Push fit bearings can be installed by hand
• Interference fit bearings are tightened on the shaft to reduce clearance when installed
• For clearance in bearings, shims are used to adjust space or gap between the shaft and bearing

Bearing Installation and Removal (cont.)

• When removing a bearing, use a puller
• Use caution when heating or cooling bearings
• Always select a proper fit to avoid damage or binding when removing or installing

Thrust Control

• The thrust of a shaft is controlled by the shaft shoulder and a collar.
• The liner material for end thrust of bearings can be solid babbitt, brass or bronze.
• There are multiple methods for dealing with thrust.

Kingsbury Thrust Bearings

• A special thrust bearing design for high speeds and heavy loads
• The design consists of a pair of rings: a revolving ring with a flat contact surface, and a stationary ring with multiple flat contact surfaces of a low-friction material
• Types of Kingsbury bearing systems include fixed pad, and tilting pad bearing systems

Angle Bearings

• Used in situations where the load is applied parallel to or at a slight angle to the horizontal, or mounted on a vertical support

Integrated Bearings

• Some heavy-duty machines utilize a base that's cast as an integral part of the machine itself rather than as a separate unit.

Joint Design

• Three general styles for bearing joints - flat joints, with a gib, and with an angle joint

Liner Materials (Cont.)

• Softer than the shaft material, so slightly deforms under heavy loads
• Wear-resistant (important to minimize wear)

Bearing Clearance

• Amount of clearance between the shaft and the bearing cap is important to prevent clamping or binding
• Clearance must be checked to prevent damage or friction
• Shims are used to adjust clearance
• P numbers classify bearing tolerance

Installing Tapered Bore Bearings

• Sleeve adapters allow for placement of a tapered bore bearing at any point on the shaft.
• The sleeve is slotted for expansion and contraction, has a threaded end which is used with a locknut for fastening
• Use caution to avoid damage to the bearing and shaft when tightening any mounted sleeve and/or locknut

Mounting Tapered Bore Bearings (Hydraulic)

• Using a hydraulic nut, the fitting is performed

Bearing Removal

• For destructive bearing removal, an oxyacetylene torch may be used

Pillow Block Installation and Removal

• Split housings typically consist of a base and a cap
• Vertically split housings use a one-piece ring and a base with separate end covers
• Common bearing designs are single-groove ball bearings, double-taper roller bearings, and spherical or concave roller bearings

Floating and Fixed Bearings

• To prevent end-float, one bearing must be fixed axially in the housing
• Floating bearings allow for movement to compensate for shaft expansion

Thrust Control Methods (Angular Contact Bearings)

• Thrust control in angular contact bearings can be achieved through a back-to- back, face-to-face, or tandem arrangement (of paired bearings)

This quiz focuses on the essential concepts and methods involved in analyzing complex materials. Participants will explore the role of skepticism in research, potential pitfalls in data interpretation, and the importance of questioning assumptions. Test your knowledge and deepen your understanding of analytical processes.