Automotive Gearbox Synchronizer Life Evaluation Using Regression Analysis under Torsional Vibration Condition 2021-26-0494

Synchronizers are the critical element in manual transmission to match the speed of target gear, and allows smooth gear shifting. Generally, synchronizer failures are related to design parameters, like geometrical construction, material, and lubrication. This paper throws light on one different parameter for synchronizer design namely the angular accelerations which are imposed on synchronizer, due to vehicle level systems.

The recent developed high-power density engines develop angular accelerations due to smaller flywheels. These angular accelerations are detrimental to the life of synchronizers. Brass synchronizers exhibit structural damage in synchronizer due to the angular acceleration. The carbon liner synchronizers do not withstand the angular acceleration and fail rapidly due to liner wear. The synchronizer rings can move freely in the available space due to rattling. The synchronizers which experience higher angular acceleration fails immediately.

The simulation of synchronizer failure on vehicles with different configurations and interface conditions are cumbersome and time-consuming activity. A test setup was developed to simulate the vehicle level angular accelerations and to prove its effect on synchronizer life. Multiple solutions were tried out with the test set up to get an optimal solution for synchronizer life. The optimal solution was tested on the vehicle for final prove out. This test set up and methodology has been successfully used for resolution of very uncommon failure mode in synchronizer. The detailed progressive path for this evolved methodology has captured in this paper. This paper presents the influence of angular acceleration on the life of the synchronizer ring and the methods to overcome the failure.