Analysis and Design of Oil Cooling Structure in Motor Shaft of New Energy Vehicle

Abstract

Due to the small volume and high-power density of new energy vehicle motor, a large number of losses in the working process are converted into heat accumulation, resulting in temperature rise, which affects its efficient operation. Based on the heat conduction mechanism, four kinds of shaft oil cooling models with different structures are designed, which are comprehensively analysed by using the thermal-fluid-structure coupling analysis method, and the most effective cooling shaft oil cooling model is solved. The simulation is based on Ansoft Maxwell, and the loss results of each component of the motor are obtained, and the loss data is imported into the Fluent software for fluid-structure coupling analysis. By keeping the other variables consistent, the oil flow rate, pressure drop, and temperature rise of four kinds of in shaft oil cooling structures are analysed and compared. The experimental results show that the rectangle around type is the optimal oil cooling structure. In addition, based on the rectangle around oil duct model , the thermal-fluid-structure coupling analysis of the whole motor is carried out, and compared with the motor without cooling system. The temperature rise cloud diagram of the two motors shows that the former has more obvious heat dissipation effect than the latter, and effectively reduces the temperature rise of the motor, especially the rotor and permanent magnet parts, which verifies the rationality of the shaft cooling structure design.