Bearings 2 Flashcards
What are bearings?
Anything that accommodates both motion and force.
What are the three types of motion associated with bearings?
- Rotary (Turning)
- Linear (Sliding or Rolling)
- Combined (Linear + Rotary)
What is a radial load?
At right angles to the shaft or axis of rotation.
What is a thrust load?
Parallel to the axis of rotation.
What is the formula for Combined Pressure?
Speed x Load = Combined Pressure (PV).
What is a plain bearing?
Non-Rolling element designed bearing.
What is a bushing?
Takes up intermediary space.
What is a sleeve in the context of bearings?
A fitting or fixture.
What are the inside and outer races in a bearing?
- Inside Race: Shaft Bore
- Outer Race: Bearing Bore.
What types of motion can plain bearings accommodate?
- Radial
- Linear
- Axial
- Oscillating.
What materials are used for metallic plain bearings?
- Bronze
- Copper and Aluminum Alloys
- Lead and Silver Babbitt
- Sintered Iron
- Copper Powders.
What are the advantages of metallic plain bearings?
- High Load Capacity
- Wide Temp Range
- High Structural Integrity
- Cost to Performance Ratio.
What materials are used for non-metallic plain bearings?
- Polyacetal
- Polyethylene
- Resin-Based Plastics
- Carbon Graphite
- Teflon Compounds
- Woven Fibers
- Natural Wood.
What are the advantages of non-metallic plain bearings?
- Handles Shock + Vibration
- Wide Temp Range
- High Structural Integrity
- Cost to Performance Ratio.
What is boundary lubrication?
Bearing and shaft rub together with only a thin film of lubricant.
What is mixed film lubrication?
Part of the load is supported by a boundary of film and the rest is supported by hydro-dynamic pressure.
What is full film or hydro-dynamic lubrication?
A thick continuous film.
What is hydro-static lubrication?
External pumps supply pressure to the lubricant providing a full film.
How can you upgrade boundary and mixed film lubrication?
- Increase Viscosity
- Increase Speed
- Decrease Load
- Improve Shaft Finish.
What is a self-lubricating bearing?
A bearing having a lubricant as an inherent or component part of the bearing structure.
What are the most common types of self-lubricating plain bearings?
- Solid Lubricant Liners
- Lubrication Plugs and Filled Grooves.
What temperature range can self-lubricating bearings accommodate?
-200 to 900 Degrees.
What are rolling element bearings?
Consists of one or two rows of steel balls or rollers.
What are the most common issues related to premature failure in bearings?
- Lubrication
- Particulate contamination
- Misalignments.
