Page 87 - Rollingbearings
P. 87
Bearing size
B.3 Bearing size
Size selection based on rating life 88
Bearing rating life 88
Bearing life deinition . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Basic rating life 89
SKF rating life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Calculating bearing life with variable operating
conditions, luctuating load . . . . . . . . . . . . . . . . . . . . . . . 90
Basic dynamic load rating, C . . . . . . . . . . . . . . . . . . . . . . . 91
Dynamic load rating for SKF Explorer bearings . . . . . . . 91
Equivalent dynamic bearing load, P . . . . . . . . . . . . . . . . . 91
Calculating equivalent dynamic bearing load . . . . . . . . . 92
Equivalent mean load . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Considerations when calculating equivalent dynamic
bearing load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Life modiication factor, a SKF . . . . . . . . . . . . . . . . . . . . . . . 94
Lubrication condition – the viscosity ratio, κ . . . . . . . . . . . 102
κ value below 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
EP (extreme pressure) and AW (anti-wear) additives . . 102
Fatigue load limit, P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Bearing size
u
Contamination factor, η . . . . . . . . . . . . . . . . . . . . . . . . . . 104
c
Size selection based on static load . . . . . . . . . . . . . . . . 104
Static load rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 B.3
Equivalent static bearing load . . . . . . . . . . . . . . . . . . . . . . . 105
Guideline values for static safety factor, s . . . . . . . . . . . . 106
0
Requisite minimum load . . . . . . . . . . . . . . . . . . . . . . . . . 106
Checklist after the bearing size is determined . . . . . . . 106
SKF life testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
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