Synchronizer is the key element for the smoother gear shift operation in the constant mesh transmission. In the gear shift operation, the double bump occurs at the contact between the sleeve teeth and the clutch body ring teeth after the full synchronization. The double bump is random in nature and the dynamics is difficult to predict. The double bump gives a reaction force to the driver and affects the gear shift quality. This paper focus on the sensitivity analysis of the synchronizer ring index percentage and the clutch body ring asymmetric chamfer angle to reduce the occurrence and magnitude of the double bump.
The system level simulation model is developed using 1D simulation tool. The modeling is done after complete declutching event so that there is no power supply to the transmission. The model can handle both upstream and downstream reflected inertia depending upon the gear shift event. The eight phases of gear shifting event such as first free flight, pre-synchronization, indexing of synchronizer ring, full synchronization, turning of synchronizer ring, second free flight, indexing of clutch body ring and complete engagement are included in the simulation model.
The simulation results have good correlation with the actual test data. The sensitivity analysis gives the optimal solution for the synchronizer parameters. The optimal values are validated on the test rig and vehicle for the improved gear shift quality.