Running performance of tandem stages type traction drive modified from angular contact ball bearings

Micro traction drive is made by modified angular-contact ball bearings. It is developed for the purpose of being small size and transmitting high torque. Structure of micro traction drive is as follows: The traction force is generated by the thrust preload between inner race and outer race. The retainer that is connected to output shaft transmits the driving torque. The retainer is made of copper alloy. The test-runs of the micro traction have been carried out as tandem stage type (reduction ratio 7.3). As results of tests, micro traction drive has been successfully operated at 20,000rpm. Further more, output shaft torque, the volume of preload of micro traction drive, and the number of balls were examined. So design manual of micro traction drive was found.