Bearings Study Guide Overview

Plain bearings

Used for heavy loads at low speeds.

Ball bearings

Applied in high speed, lighter load applications.

Needle bearings

Carry heavy radial loads in minimal space.

Bearing failure

Rarely due to fatigue; often due to service life.

Eccentric locking collars

Not suitable for bi-directional applications.

Radial bearings

Support loads perpendicular to their axis.

Bearing mounting method

Depends on fit type and bearing style.

Angular contact bearing

Most common type of thrust ball bearing.

Tapered bearings

Designed for heavy thrust and radial loads.

Hydrostatic lubrication

External pumps supply lubricant pressure, preventing contact.

Full-film lubrication

Thick lubricant film prevents metal-to-metal contact.

Mixed-film lubrication

Part load on boundary film, part on hydrodynamic pressure.

Boundary lubrication

Thin lubricant film allows shaft and bearing contact.

Bearing selection factors

Consider load, speed, and temperature.

Sleeve bearings

Another name for plain bearings.

Spherical roller bearing

Known for high speed capabilities.

Inner race

Part of the bearing that fits onto the shaft.

Outer race

Part of the bearing that encases the inner race.

Separator/Cage

Holds bearing balls in place within the assembly.

Ball bearing interference

0.00025 inches per inch of shaft for press fit.

Nylon and Teflon bearings

Suitable for chemical applications; no lubrication needed.

Temperature effect on bearings

Over 250°F may reduce metal hardness, causing failure.

Precision class deviation

Over 0.0005 inches causes significant vibration.