Drive system for rigid axle electric vehicles

Abstract

The present invention provides a drive system for a rigid axle type electric vehicle that provides sufficient space under the vehicle body for locating the traction battery. [Solution] The transmission shaft 44 that transmits power from the electric drive unit MDU to the final reduction gear 22 is arranged in the vehicle width direction. One end of the transmission shaft 44 in the vehicle width direction is connected to the electric drive unit MDU via a vehicle body-side constant velocity coupling (first coupling) 66, and the other end of the transmission shaft 44 in the vehicle width direction is connected to the final reduction gear 22 via an axle housing-side constant velocity coupling (second coupling) 68. As a result, in the electric vehicle 10, compared to the case where the transmission shaft 44 is arranged in the vehicle longitudinal direction, sufficient space for arranging the traction battery is obtained under the floor of the vehicle body 14.

Claims

1. A rigid axle type electric vehicle drive system in which an axle housing, which connects the left and right drive wheels and houses a final reduction gear that distributes power from an electric drive unit provided on the vehicle body to the drive wheels, supports the vehicle body via suspension springs, The transmission shaft that transmits power from the electric drive unit to the final reduction gear is arranged in the vehicle width direction. One end of the transmission shaft in the vehicle width direction is connected to the electric drive unit via a first coupling, and the other end of the transmission shaft in the vehicle width direction is connected to the final reduction gear via a second coupling. A drive system for a rigid axle type electric vehicle, characterized by the following:

2. The suspension springs are a pair of coil springs, and the axle housing is restricted from moving in the vehicle width direction by a lateral rod, one end of which is connected to the vehicle body in the vehicle width direction and the other end of which is connected to the axle housing in the vehicle width direction. A drive system for a rigid axle type electric vehicle according to feature 1.

3. The final reduction gear comprises a differential gear mechanism that distributes power to the left and right drive wheels via a pair of drive shafts, and a reduction mechanism consisting of a pair of cylindrical gears provided around the rotation axis of the differential gear mechanism and a rotation axis parallel to the rotation axis of the differential gear mechanism, wherein the rotation direction of the transmission shaft is opposite to the rotation direction of the drive shaft. A drive system for a rigid axle type electric vehicle according to feature 1.

4. The final reduction gear comprises a differential gear mechanism that distributes power to the left and right drive wheels via drive shafts, a pair of sprockets provided around the rotation axis of the differential gear mechanism and a rotation axis parallel to the rotation axis of the differential gear mechanism, and a transmission chain wrapped around the pair of sprockets. A drive system for a rigid axle type electric vehicle according to feature 1.

5. The electric drive unit includes an electric motor and a reduction gear that reduces the rotation of the electric motor. The reduction gear comprises an input shaft that protrudes toward the motor and is connected to the motor, and an output shaft that protrudes toward the motor and is connected to one end of the transmission shaft in the vehicle width direction. A drive system for a rigid axle type electric vehicle according to feature 1.

6. The first and second joints are constant velocity joints, and at least one of the first and second joints is a sliding constant velocity joint that allows axial sliding. A drive system for a rigid axle type electric vehicle according to feature 1.

7. The aforementioned final reduction gear is lubricated with a lubricant of lower viscosity than the lubricant used for hypoid gears. A drive system for a rigid axle type electric vehicle according to the features of 3 or 4.

8. The final deceleration device comprises the reduction mechanism and the differential gear mechanism that transmits power from the reduction mechanism to the left and right drive wheels via a pair of drive shafts, respectively. The axle housing comprises a pair of small-diameter sections for housing the pair of drive shafts, and a large-diameter section provided between the pair of small-diameter sections for housing the reduction mechanism and the differential gear mechanism. At least the largest diameter portion of the large-diameter section is positioned so as not to overlap with the electric drive unit in the direction of vehicle travel. The drive system for a rigid axle type electric vehicle according to feature 3.

9. The suspension spring is a pair of leaf springs composed of a single plate-shaped spring or multiple plate-shaped springs stacked together, with both ends in the longitudinal direction connected to the vehicle body and the central part in the longitudinal direction connected to the axle housing. The axle housing is restricted from moving in the vertical and vehicle width directions by the leaf spring. A drive system for a rigid axle type electric vehicle according to feature 1.

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