Smooth clutch operation in automatic transmissions is
strongly tied to the velocity dependence of the coefficient
of friction (COF). Full-scale clutch tests, such as the JASO
M348 or any other OEM-specific test protocol run on the
SAE No. 2 Friction Test Machine, are typically used to
obtain friction data, but these tests are both expensive
and time consuming. Further, the evaluation of each new
friction material recipe or process change requires the
fabrication and assembly of full-scale clutch components.
Significant savings in development time and cost can be
realized by screening friction materials in the laboratory
prior to full scale clutch tests. This application note
discusses the benefits of this process using the Bruker
UMT TriboLab™ benchtop tester.