Reduction differential gear apparatus for electric vehicle

摘要

An object is to reduce various losses occurring in a speed-reduction/differential gear apparatus for electric vehicles including a planetary-gear speed reducer and a differential device, thereby improving transmission efficiency of the driving force and increasing travel distance of the electric vehicle per battery charge. A speed-reduction/differential gear apparatus for electric vehicles includes a planetary-gear speed reducer and a differential device. A planetary gear mechanism in the speed reducer includes a speed-reducer-side carrier which has its inner diameter surface supported by a speed-reducer-side carrier support bearing. The invention provides proper mesh between in the pair of engaging teeth, leading to decrease in loss torque.

主权项

1. A speed-reduction/differential gear apparatus for electric vehicles, comprising:
an electric motor; a planetary-gear speed reducer and a planetary-gear differential device which are disposed coaxially with the motor; a casing housing the electric motor, the planetary-gear speed reducer, and the planetary-gear differential device; a first output shaft penetrating a motor shaft of the electric motor, the first output shaft having two end portions supported by the casing via respective output shaft support bearings; and a second output shaft disposed coaxially with respect to the first output shaft, driving force from the electric motor receiving speed reduction by the speed reducer and being outputted to the differential device; the speed-reduced driving force being outputted to two distribution members by the differential device in accordance with a size of load; one of the distribution members being connected with the first output shaft whereas the other one of the distribution members being connected with the second output shaft; wherein the speed-reduction/differential gear apparatus for electric vehicles further comprises a speed-reducer-side carrier support bearing disposed between a speed-reducer-side carrier, which constitutes part of a planetary gear mechanism of the speed reducer, and the casing, wherein the speed-reducer-side carrier has a boss, the speed-reducer-side carrier support bearing is disposed between an outer diameter surface of the boss and the casing, and a motor shaft support bearing is placed between an inner diameter surface of the boss and the motor shaft of the electric motor.