Anti-Friction Bearings Flashcards
Anti-Fructiin bearings Part A, Part B, MWM
What are the main functions of the rolling elements?
- To support the load
- Roll at all times
- To replace sliding friction with rolling friction
What factors affect the bearings ability to carry load?
- area of contact
- direction of load
- degrees loaded zone
What is the area of contact on a ball bearing versus a roller bearing?
Ball bearing- circular until load applied to ball then elliptical
Roller bearing- narrow rectangle, contact areas larger as rolling element size decreases
What are the three directions of load?
Radial load, axial load, and combination load
What is the loaded zone on what factors can change it?
Area loaded on the bearing. Depends on direction of load, internal clearances
List some characteristics of single row deep groove ball bearings
- general purpose
- mostly for radial load
- supports combination and moderate axial loads
- Contact angle changes with direction of load
- tolerates a small amount of misalignment
What is different about a maximum capacity deep groove ball bearing?
- loading slots are machined into the raceways to accept more balls
- higher radial load capacity, lower axial load capacity
- sensitive to misalignment
What is different about a double load deep groove ball bearing?
- Provides higher radial load capacity without increasing radial dimensions
- Restricted to radial loads
What are some characteristics of internally self-aligning ball bearings?
- used when alignment is impractical or impossible to maintain possibly due to shaft deflection
- often used at coupling end of overhung shaft in combination with other bearing
- supports only small thrust in either direction
- speed rating is same as single row deep groove ball bearings
- available with tapered bore and can be located anywhere on shaft
- used in high-speed high-accuracy applications
What are some characteristics of externally self-aligning ball bearings
- Spherically ground outer ring mounts into special housing
- outer ring allows for misalignment in mounting
What are some characteristics of single row angular contact bearings?
- accommodate radial and thrust loads
- can mount in tandem
- axial load capacity increases with increase in contact angle
- Low shoulder allows higher number of balls
- Inner and outer rings can be moved to adjust clearance
- Available in standard or precision series
What are three arrangements for pairs of single row angular contact bearings?
- face to face
- back to back
- in tandem
What are some characteristics of double row angular contact bearings?
- takes heavy radial and axial loads in both directions
- speed rating is lower than deep groove or single row angular
- cannot tolerate misalignment
What are some characteristics of the four point angular contact ball bearing?
-Can only be used for axial or combination loads
Can handle reverse axle loads (Gothic Arch)
-it is a separable bearing with a split inner ring
-Can be manufactured with large number of balls
Often used as thrust bearing with radial clearance
-tolerates minimalmisla
What are some characteristics of the four point angular contact ball bearing?
-Can only be used for axial or combination loads
Can handle reverse axle loads (Gothic Arch)
-it is a separable bearing with a split inner ring
-Can be manufactured with large number of balls
Often used as thrust bearing with radial clearance
-tolerates minimalmisla
What are some characteristics of the four point angular contact ball bearing?
- Can only be used for axial or combination loads
- Can handle reverse axle loads (Gothic Arch)
- it is a separable bearing with a split inner ring
- Can be manufactured with large number of balls
- Often used as thrust bearing with radial clearance
- tolerates minimal misalignment
What are some characteristics of a ball thrust bearing?
- Pure thrust only
- One or two direction thrust or one direction self-aligning thrust
- non self-aligning cannot tolerate misalignment between shaft and housing
- speed limit is half the limit for a radial load bearing
- intended for slow speeds
What are four types of roller bearings?
- cylindrical
- needle
- tapered
- spherical
What are some characteristics of cylindrical roller bearings?
- Separable in two directions and can only bear radial loads
- Larger contact area than ball bearing in same diameter
- Can only handle small amount of misalignment
What are three common types of needle bearings?
- no cage or inner ring
- drawn steel cup and no inner ring
- Machined inner and outer rings
What is the difference between a roller and a needle rolling element?
Needles are similar to rollers but they are two and a half to 10 times length to diameter ratio
What are some advantages of needle bearings?
- their smaller diameter allows use wherespace is limited
- extended length gives high load capacity
What are some characteristics of tapered roller bearings?
- tapered raceways allow heavy combined loads in one direction
- used in pairs to accommodate reversing loads and avoid separation
- their tapered design allows internal clearances to be set by moving cup and cone closer or further apart
- tolerate little misalignment
