Bearings Flashcards
What is true brinelling?
Sudden impact usually poor fitting technique.
Identified by ecliptial dents in sides of race
What is false brinelling?
Usually caused by vibration often second hand when in service but no running.
Identified by less prominent ball marks
What is slipping / skidding?
Caused by slack fits too shaft or housing,
Identified by polish
What is fretting?
Similar to skidding however parts of housing broken away which act as abrasive to Bering during service
What is overheating?
Caused by lack of lubrication
Discolouration as evidence
What is tight fits?
Internal clearances taken up causing friction - overheating
What is expressive loading?
Causes premature failure, spalling seen on races as evidence
What is normal fatigue?
Bearing lifeline exceeded causing failure, spalling in raceway which chips out
What is lubricant failure?
Discolouration caused by overheating
What is contamination?
Debris / abrasives acting on races and balls
What is the axial clearance of a pair of angular contact bearings?
1-2 thou
What is the axial clearance of a normal thrust bearing?
0-1 thou
What is the required clearance between a bearing and its housing?
0.5 - 1.5 thou CLR
What is the required clearance of a bearing to a shaft?
Size for size minimum
