Mechanical Performance of 5-speed Manual Transmission Gearshift Bracket

Abstract

The main purposes of a gear shift bracket for manual transmission are to hold the gear shift cables and acts as pivot during the gear shifting process. During the gear shifting process, the bracket experiences push and pull reciprocating forces which applied by the driver while selecting or shifting gears. This study presents the development of a simulation model to analyze the mechanical performance of a specific manual transmission gearshift bracket. Based on the simulation results, an optimized bracket design was proposed. Commercial CAD software and Finite Element (FE) Method software were used to perform the simulation. Boundary and initial conditions were applied to the FE model which was based on the real-life mechanical movement of the bracket during gear shifting process. The boundary and initial conditions included fixed position, displacement and both select and shifting loads by following actual test requirements which replicated the movement of the actual model during gear shifting process. Specific mechanical ratio formula was used to obtain the magnitude of loads that was experienced by the gear shift bracket in both select and shifting gears action. The simulation of the gearshift bracket provided outcome parameters such as total deformation, maximum stress and safety factor value. Based on the safety factor value, the model was eligible for topology optimization process and it was modified to gain the optimized model. Then, the same simulation setup was used for the optimized model. The modified design bracket was able to provide a 7% reduction in mass, a 25.15% increase in maximum deformation, a 46,78% increase in maximum stress and, a 36.74% decrease in safety factor value by comparing it to the original model. Although the modified model has lower strength, but its safety factor value is still within the minimum requirements. This concludes that the simulation model allows the manufacturer to undertake design iteration and analyze its performance without producing any physical prototypes and conduct any actual test, thus saving development cost and time.