Abstract
Given the differing structure of transmissions for pure electric vehicles from the conventional ones, how to enhance the transmission performance is the key to improving their dynamic property and economical efficiency. In this work, a two-speed planetary transmission for a self-designed 10–12 m bus is studied. A simulation model of the transmission is created according to the gear meshing principle, and the load spectra are established by simulating the probable loads on the transmission in actual operation. The gear drive process of the transmission is analyzed, as along with the gear safety factors, damage rates and meshing dislocation. Trimming curves are derived based on the principles of axial and tooth profile modification, the trimming amounts are set, and the contact spots and transmission errors of gear meshing obtained before and after trimming are analyzed comparatively using the MASTA’s gear microscopic trimming module, thereby determining the reasonable method and quantity of trimming for the studied transmission gear. Comparison of the contact spots and transmission errors before versus after trimming finds greatly improved contact condition of gear and more stable gear transmission. With the methodology described in this paper, the shortcomings of traditional gear trimming, such as cumbersome process, long duration and nonlinear gear drive system, can be overcome, which improves the operational reliability.