Bearing Misc. Flashcards
Pitting
Arc damage in a stationary bearing
Fluting
Arc damage in a rotating bearing
Electric arc
-an electric arc jumping across the clearance inside the bearing and leaves a track on a surface
Causes of arcing
- welding on the supporting structure next to the bearing with the ground attached at the opposite side of the bearing
- electric charge s can develop in the shaft and housing of high-speed machinery
Operating above recommended load.
-shortens life by 90%
Operating above recommended speed
Reduces life by 50%
Lip Seal
- makes a seal by pressing the seal lip against the seal surface
- its the initial light contact pressure before start up
- temperature restricted to -40 to 200 degrees C
External seal
- a seal on the bearing housing
- Advantage of offering a wide selection
Integral Seal
- seal attached to the bearing
- has the advantage of being cheap and more compact than external
V-ring
- attached to the shaft and contacts the surface of the housing
- 15 meters per second the lip will lift
- low speed seal can operate with a large amount of axial movement
Mechanical seal
- a stationary ring and a rotating ring made out of carbon
- leak proof
Split Joint Pillow Block
-gib joint can handle the greatest side load
Unit Pillow Block
-the eccentric collar must be tightened in the direction of rotation
Temperature is a result of what?
- Friction
- how fast the heat is dissipated
- heat transferred from the outside
How much hotter could the rolling elements be compared to the outside surface when you check it?
20 degrees C, add another 10 degrees for the inner ring
High amperage reading?
-abnormal load on machine
Sounds from a bearing
- loud hollow noise could mean too much clearance
- high pitch whine could mean too little clearance
- growling noise could mean rollers and raceways are deteriorating
Spalling
-the pitting and flaking that occurs from the micro-cracks in the loaded zone as the rolling element continuously goes through the loading and unloading zone
Transducer
-a device that picks up the vibration and converts it into an electrical signal to give a reading
Oil Analysis
- darkened oil indicates oxidation and means the oil should be changed
- sludge and acids in the oil is advanced oxidation and indicates a need for short intervals in oil changes
Issues that could cause High Temperature
- lubrication issues
- a seal rubbing too hard
- bearing is failing
- increase in load or speed
- additional heat from an outside source
What split joint pillow block can handle the greatest side load?
The Gib
External rubbing seals?
-Lip, v-ring, felt
External non-rubbing seal?
- Radial Labyrinth
- Axial Labyrinth
- combo Labyrinth
- seal washers
- flinger
Locating ring (fixing or stabilizing)
-On fixed bearing at the drive end
Unit pillow block Eccentric locking collar
-tightened in the direction of rotation
