Strain based preload measurement in drive axle pinion bearings

Abstract

Bearing setting has a significant impact on bearing life and system performance. A strain based load measurement technique that has been previously developed and patented will be used to measure preload in automotive drive axle pinion bearings. This technique utilizes strain gages placed in notches that have been machined into the outer diameter of a bearing cup. The performance of two gage types, semiconductor and metal foil, are compared. Preload in the pinion bearings is simulated in a machine by applying an axial load to a bearing assembly. The bearing assembly is rotated at various speeds and temperatures for each set of axial loads. Two notch geometries are compared for each set of tests conducted. An effort has been made to develop a finite element model that can be used to verify the results of the gage calibration. The results of the calibration reveal that metal foil and semiconductor gages can provide preload measurements that are accurate to within 3.7% and 7.7% of the full scale input load (73 lbs. and 155 lbs.) respectively.