Investigation of Thermal Influences on Wear Behavior in Geared Transmissions

Geared automotive and aerospace transmissions are one of the most critical systems regarding wear. Limiting wear is of paramount importance to improve sustainability by reducing replacements that lead to increased waste and energy consumption for re-manufacturing. Simulation of gears including the wear effect can be very useful for the design of new more efficient and compact gears. Thermal effects may play a decisive role in the wear phenomena and should be included in the models used for simulations. In this study, some tests are conducted on a pin-on-disk apparatus under varying temperatures to assess its influence on steel-to-steel wear rate. A modified Archard law is used for wear estimation which includes the experimentally derived parameters accounting for thermal effects. This model is then coupled with a loaded tooth contact analysis (LTCA) tool to obtain accurate predictions of the contact pattern, as well as the instantaneous load shared by the mating teeth pairs during the meshing cycle. This coupled simulation framework is then employed to carry out simulations of wear evolution during the lifespan of a gear pair. A comparison between wear simulations using a constant wear coefficient and one incorporating temperature dependency is presented. The wear law as function of temperature is scaled to account for boundary lubrication condition. Results put in evidence a limited impact of the local temperature on wear with this preliminary approach. The differences however increase with the number of working cycles.