The main reasons for bearing testing are: •Technical validation / supplier approval •Comparative assessment (applies to different suppliers or to different production methods •Continuous quality control for incoming or outgoing inspections We use an overview of different testing methods, the required equipment and testing strategies. The main testing methods are for frictional torque or temperature and for endurance. Both have their justification depending on what is most critical in the associated application.
Testing methods: Among testing methods, one firstly has to distinguish between testing for frictional torque or temperature and testing for endurance. Friction and temperature testing can help understand the effect of various operating conditions on the frictional torque and the equilibrium temperature. Such tests can help to evaluate power losses due to friction which contribute to the overall system efficiency. As an example, the losses in individual bearing elements in the drivetrain of an automobile and hence the total efficiency of the drivetrain can be evaluated. This testing method can also be used to provide a quick evaluation of the quality standards of regular deliveries (incoming inspections) and to identify performance limits. Finally, steady state temperature can be a performance limiting criterion for grease lubricated bearings.
Endurance testing is used in order to evaluate the bearing lifetime under sustained use. Testing can be used to validate if the performance of the bearing and the lubricant comply with the technical specifications or expectations. When switching to or acquiring a new supplier one typically needs to ensure that the performance of the new product is better – or at the least not worse – than the current supplier. An accelerated endurance test can provide a quick comparative assessment of different suppliers and help one to make an informed decision. An endurance test which extends beyond theoretical life rating can also provide a quick test for incoming inspection.