A critical characteristic in clutch material friction behavior is a flat or positive gradient of friction coefficient with increasing velocity. A negative gradient promotes stick-slip behavior, which can lead to undesirable clutch performance characteristics, such as shudder and judder. In this webinar, we cover the motivation and method of a bench-top screening test for the friction characteristics of clutch materials and automatic transmission fluids (ATFs). Such testing is key to the decrease in development time via the ranking of clutch materials and fluids prior to selection for standardized full-scale component test rigs or in-service vehicle field testing. Screening tests are conducted using industry-relevant test conditions, similar to those from the SAE #2 friction test machine, or per the JASCO M348-2012 test standard, including contact pressures, sliding velocities and temperatures. At the conclusion, we present results from bench-top screening tests of paper-based clutch materials which rank materials in the same manner they are ranked when full-scale clutches were tested.
Dr. Steven Shaffer
Global Senior Applications Scientist - Tribology, Stylus and Optical Metrology