Bearings - Anti Friction Flashcards
Spherical roller bearing?
- ISO #2
- barrel-shaped rollers provide a wide load carrying contact area
- combined thrust in both directions and radial load capacity
- the spherical track on the outer race allows for internal self alignment
- high radial load, minimal thrust
3 functions of the cage?
- prevents the rolling element from rubbing against each other
- push rolling elements through the unloading zone
- no pushing needed through loaded zone because of the traction provided by the load
- guide the rolling elements with minimum amount of friction
CARB
- compact aligning roller bearing
- the shape makes it radially compact like a needle bearing, but with some of the misalignment capabilities of the spherical roller
- not good for thrust
Diametral Clearances
- Initial or Bench
- Residual or Installed - 1/2 bench clearance during installing
- Running
Single Row Deep Groove Ball Bearing
-ISO #6
-most common ball bearing
-Conrad bearing
-mainly to support radial loads
-can support combination loads and moderate axial loads in both directions
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Single Row Angular Contact Ball Bearing
- ISO #7
- substantial thrust load in one direction
- higher load rating than deep groove ball bearings
- can be mounted against each other or together with a spacer between them (arrangements)
- must operate with an axial load component
Tapered Roller Bearings
- ISO #3
- Inner ring also called cone and outer ring called cup
- best for combination load
- should be preloaded
- has a pressed steel cage which is the most common
- also has a Pin Cage which can support more load because point of contact is closer together.
Loaded Zone
- the area of the bearing that has force on it. Radial will have less than axial because how the pressure is applied
- loaded zone depends on the amount of internal clearance and preload as well
Needle Bearings
- has no cage or inner ring, needles are retained by grease
- 2 1/2 to 10 times as long as their diameter
- when installing ensure you use the proper size mandrel so the wall of the cup doesn’t get crushed
Brinelling
- excessive pressure on a ball bearing by hammer or force
- impact denting
Cylindrical Roller Bearings
-Separable in both direction
-only support radial loads
-
Cylindrical roller thrust
- very heavy thrust load
- rollers are laying differently
Single row angular contact ball bearing arrangements
- Face to face
- Tandum
- Back to back used as back up bearings rigid
Face to face Arrangement
- can handle reversing axial loads
- suitable for use in housings with less accuracy or larger shaft deflection due to low bending stiffness of the shaft
Tandum Arrangement
-can handle more radial load than face to face and back to back, but can only handle axial load in one direction towards the high shoulder on the outer ring
Back to Back arrangement
- can handle reversing axial loads
- used as back up bearings
- are mounted further apart so they can hold the shaft more rigidly in angular alignments
- more rigid than face to face
Four Point Angular Contact Ball Bearings
- can be used for only combination or axial loads so that the load does not run on the split
- is a separable bearing
- can handle reversing thrust reversing thrust loads in either direction because of the shape of the raceways
Maximum Capacity Deep Groove Ball Bearing
- has more balls than deep groove because of the loading slots machined into the inner and outer raceways.
- higher radial load
Internally self aligning ball bearings
- inner part of the outer ring is spherical
- used when alignment is impractical or impossible to maintai
- small thrust loads in either direction
- available with a tapered bore for mounting on a tapered adapter sleeve or tapered withdrawal sleeve for mounting against a shoulder.
Externally self aligning ball bearing
- has a spherically ground outer ring that mounts in a special housing.
- intended to accommodate angular misalignment in mounting
externally compared to internally self alignin
-internal can support only relatively small axial loads, more suitable for where shafts wobble back and forth with each rotation
False brinelling
- same as brinelling but caused by vibration
- happens over time when brinelling happens right away
Two methods of retaining rollers in a needle bearing?
Grease and drawn steel cup
ISO
- 1 number is bearing type
- 2,3 is the dimension series
- last 2 bore diameter (the number x5) or exceptions 00-10, 01-12, 02-15, 03-17 or sizes over 500mm