Motor drive device

1. A motor drive device comprising:

a trailing arm that extends in a vehicle front-rear direction and comprises a vehicle body-side attachment portion and a wheel-side support portion, the vehicle body-side attachment portion formed on a front side of the trailing arm and coupled to a vehicle body via an elastic member, the wheel-side support portion formed on a rear side of the trailing arm and supporting a wheel; and

a motor that is supported by the trailing arm and drives the wheel,

wherein the motor and the elastic member are disposed in such a way that the motor and the elastic member are seen as being substantially aligned in a vehicle up-down direction when viewed in a vehicle width direction.

2. The motor drive device of claim 1 ,

wherein the trailing arm further comprises a motor bracket which extends downward from the vehicle body-side attachment portion and to which the motor is attached.

3. The motor drive device of claim 2 , further comprising

a gear transmission mechanism that transmits power of the motor to the wheel,

wherein the gear transmission mechanism has a gearbox arrangement attached to the trailing arm as a rigid body,

wherein the gearbox arrangement comprises a first gearbox and a second gearbox arranged separately from each other, the first gearbox housing a first gear unit disposed about a rotating shaft of the motor, the second gearbox spaced apart from the first gearbox and housing a second gear unit disposed about a rotating shaft of the wheel.

4. The motor drive device of claim 3 ,

wherein the first gearbox is attached to the motor bracket.

5. The motor drive device of claim 4 ,

wherein the trailing arm includes a first gearbox support surface portion formed on the motor bracket and a second gearbox support surface portion spaced apart from the first gearbox support surface portion in the vehicle front-rear direction,

wherein the first gearbox is attached to the first gearbox support surface portion, and

wherein the second gearbox is attached to the second gearbox support surface portion.

6. The motor drive device of claim 4 ,

wherein the motor is attached to the motor bracket via the first gearbox.

7. The motor drive device of claim 3 ,

wherein the gear transmission mechanism includes a bending mechanism for absorbing a twist that occurs between the first gearbox and the second gearbox due to deformation of the trailing arm.

8. The motor drive device of claim 7 ,

wherein the bending mechanism is a constant velocity joint.

9. The motor drive device of claim 3 ,

wherein the gear transmission mechanism comprises:

a first transmission shaft extending from the first gearbox; and

a second transmission shaft extending from the second gearbox and spline coupled to the first transmission shaft.

10. The motor drive device of claim 1 ,

wherein a torsion beam extending in the vehicle width direction is attached to the trailing arm,

wherein a seat is disposed forwardly of the torsion beam, and

wherein the motor is located between the torsion beam and the seat.

11. The motor drive device of claim 1 ,

wherein the motor partially projects downward further than a lower surface of a floor panel of the vehicle body.

12. The motor drive device of claim 1 ,

wherein the wheel-side support portion has a wheel-side support member with a function of adjusting alignment of the wheel,

wherein the trailing arm is made up of an outer member and an inner member disposed opposite to each other in the width direction of the vehicle and together forming a main body portion with a closed cross-sectional shape,

wherein the outer member has an intermediate portion that is located intermediate between front and rear ends of the outer member and a widening portion extending rearward from the intermediate portion and widening in the up-down direction of the vehicle,

wherein the wheel-sided support member has a fixing portion fixed to a width direction outer side of the widening portion, and

wherein the widening portion has a mounting portion which is on an inner side in the width direction and on which a drive mechanism is mounted.

13. The motor drive device of claim 12 ,

wherein the trailing arm further includes a reinforcing member bonded to the inner member and extending on a rear end side,

wherein the inner member and the reinforcing member are disposed such that a rearward portion of the inner member and a rearward portion of the reinforcing member are spaced apart from each other in the up-down direction, and

wherein the mounting portion is located between the inner member and the reinforcing member.

14. The motor drive device of claim 12 ,

wherein the fixing portion comprises an upper fixing portion and a lower fixing portion spaced apart from each other in the up-down direction, and

wherein the mounting portion is located between the upper fixing portion and the lower fixing portion.

15. The motor drive device of claim 12 ,

wherein the widening portion includes a forward wall portion that covers a front side of the drive mechanism mounted on the mounting portion, and

wherein the forward wall portion has an opening that opens in the vehicle front-rear direction.

16. The motor drive device of claim 12 , further comprising a spring seat that is fixed to the trailing arm and supports a lower end side of a suspension spring,

wherein the inner member is disposed on an upper side relative to the mounting portion,

wherein the reinforcing member is disposed on an lower side relative to the mounting portion, and

wherein the spring seat is fixed to the reinforcing member.