Study And Application Of The Gear Flank Micro-geometric Modification On The Noise Reduction Of Automobile Transmission

This paper applies the method of flank micro-geometric modification to optimize gear pair’s contact meshing conditions and decrease the gear pair’s transmission error after loaded.Reducing the gear whine noise of internal 5-speed manual passenger-vehicle transmission in the driving process is mainly optimizing and designing gears objective in the paper,at the same time,avoiding some faults of older methods,e.g.when designing the gear flank micro-geometric modification in order to improve the NVH characteristics of the transmission,the gears’ strength often were omitted,the stiffness of beatings and housing were not considered completely and the influence from involutes and helicoids were not considered completely when modified the helical gear pair.The main contents and results of the paper are following:(1) The mechanism of gears excitation and gears noise,the relationship of gears misalignment,transmission errors with gears noise,the methods and principles of gear flanks micro-geometric modification,the relationship of gears contact patterns and gears noise are studied and the optimizing and design method of composite micro-geometric modification is provided.(2) Taking the professional gear design and optimization software, RomaxDesigner,as tools,gears,shafts,bearings,synchronizers,housings and the differential are modeled for optimization and design of the gear flank micro-geometric modification parameters under the preconditions of good gear bending and contacting strengths,then the gears transmission errors and contact patterns were predicted. (3) The gears contact patterns of the designed & optimized prototype are analyses and then modify the gear micro-geometric modification parameters in order to eliminate the influence of gear manufacturing and transmission assembling processes by applying multi-factor DOE method.(4) At the final stage,the subjective and objective evaluation of the preand post-optimization gear noise validated the method of the design and optimization through the test in test bench and in vehicle on test track.The results showed the gear whine noise were obviously improved,the design & optimization are successful and the effects are valid and reliable.The paper has some guide for the design and optimization of gearbox NVH characteristics in current local automobile transmission manufacturers, helps them to design better NVH characteristics transmission,especially the transmission for passenger vehicle.Finally it is helpful to raise the design ability of our domestic automobile transmission enterprises.