Development of an Assessment Methodology for synchronizer ring (CuZn Alloy) wear durability

An optimized gear shift feeling throughout the life of a MT Gearbox is one of the major challenges during transmission development. Synchronizer ring’s function during its intended life play important role to get optimized gear shifting effort. Any undesired synchronizer ring (CuZn Alloy) wear causes high effort in gear engagement during vehicle running and discomfort to the driver. High wear rate reduces the life span on synchronizer ring. Current paper explains the experimental approach for study of critical parameters on synchronizer ring wear and Coefficient of friction (COF) under controlled temperature environment on test bench. Gear shift loading conditions based on Reflected Inertia (kgm2), shifting time (sec), shifting load (N) on gear knob and speed difference (rpm) between gears were calculated on synchronizer ring level and accordingly the loading conditions such as sliding speed (m/s), axial pressure (N/mm2) and synchro energy (J) were decided. As synchro wear rate and behavior coefficient of friction (COF) has impact on gear shifting effort, so the Relationship between input loading parameters were studied w.r.t. wear rate and coefficient of friction (COF).