Gear Modification And Test Research To Two-speed Transmission Of Electric Vehicle

As cars have become an indispensable means of transport in modern society,the problems that it brings must be paid attention to.Among them,the depletion of traditional energy and the increasingly serious environmental pollution are increasingly serious concern.How to develop clean and non-polluting vehicles has became one of the important topics of current research.The transmission is an important part of the automobile transmission system,and it is also the main contributor to the vibration and noise of the transmission system.For electric vehicles,the transmission noise is more significant because there is no engine and exhaust system noise.Domestic research on electric vehicles is in a period of rapid growth,but there are still some problems.There is no mature and reliable method to the study for the performance of transmission NVH.In this paper,a two-speed electric vehicle transmission is studied,and the transmission NVH performance factors and optimization have been discussed.Build an electric car module in AVL Cruise to analyze the efficiency of a motor when it matches a one-speed transmission and a two-speed transmission.The results show that the working point of the motor is shifted to the high-efficiency zone when the two-speed transmission is matched,which can prolong the mileage of the electric vehicle.In addition,two-speed transmission can not only improve the vehicle's dynamic performance,but also can increase the ability to climb at low speed.For the existence of machining and assembly errors,gear,which is the key component of transmission,will cause meshing impact and partial load on the tooth surface which will increase the vibration and noise and reduce load carrying capacity.Gear modification technology is the most cost-effective way to solve the above problems.The modification parameters need to be determined according to the transmission error of gears,contact spots and the vibration response of the gearbox during the operation of transmission.The effects of different modification parameters on the modification effect are quite different.When the modification parameter is improperly selected,the normal meshing will be affected.Therefore,the research on gear modification parameters design is of great theoretical significance and practical value.The coupling model of Rigid-Flexible transmission was established in Romax Designer,and its coincidence degree analysis,axis deformation analysis,meshing mismatch analysis,meshing mismatch contribution analysis,transmission error analysis,contact spot analysis and vibration response analysis are carried out.The microscopic modification of the transmission gear can reduce the transmission peak-to-peak error,improve the tooth surface force and reduce the surface vibration shell,which is optimized transmission NVH performance.Giving full consideration to the machining error on the actual effect of shape modification,the tolerance analysis is carried out.With the vibration at the bearing bore derived from Romax Designer,the entire housing vibration of the transmission is calculated in the LMS virtural-lab to obtain the radiated noise of the housing.In order to evaluate the noise performance of electric vehicle transmission,this paper also carries out a bench test on the transmission prototype.