7、,et al. Design and Development of Few-Tooth-Deference Planetary Gear Powertrain Coupling System with Biased Bent Shaft in Electric and HEV for All-Terrain Vehicles–––IEEE Vehicle Power and Propulsion Conference (VPPC), Sept. 3-5, 2008,68~71.[5] 常思勤.《车辆动力装置》[M]. 北京: