Vehicle drive device

1. A vehicle drive device including a transmission mechanism that selectively establishes one of a low range and a high range, a range changing mechanism that changes the ranges of the transmission mechanism, a motor generator that inputs drive force to the transmission mechanism, and a control device that controls the changing of the ranges, wherein

the range changing mechanism includes a low gear piece and a high gear piece that are arranged and spaced apart in an axial direction, a clutch sleeve that is slidably arranged in the axial direction so as to be engaged with one of the two gear pieces, and a shift actuator that slides the clutch sleeve either forward or backward in the axial direction to be connected to one of the gear pieces, and when the clutch sleeve is connected to the low gear piece, a low-range power transfer path is established, and when the clutch sleeve is connected to the high gear piece, a high-range power transfer path is established,

the control device includes

an actuation processor that rotates the connection target gear piece in the same direction as a direction of input rotation to the transmission mechanism in response to a range change request when a vehicle is stopped, and slides the clutch sleeve,

a determination processor that determines whether or not the clutch sleeve has become unable to slide during the process of sliding the clutch sleeve, and

a handler that, when the determination processor determines that the clutch sleeve has become unable to slide, causes the motor generator to rotate the connection target gear piece in a direction opposite to the direction of the input rotation to the transmission mechanism.

2. The vehicle drive device according to claim 1 , wherein

the actuation processor causes the motor generator to rotate the connection target gear piece in the same direction as the direction of the input rotation to the transmission mechanism in response to the range change request, before causing the shift actuator to slide the clutch sleeve.

3. The vehicle drive device according to claim 2 , wherein

a second motor generator and a main transmission mechanism are provided between the motor generator and an input shaft of the transmission mechanism, and an engine is provided between the second motor generator and the motor generator via a power split device.

4. The vehicle drive device according to claim 1 , wherein

a second motor generator and a main transmission mechanism are provided between the motor generator and an input shaft of the transmission mechanism, and an engine is provided between the second motor generator and the motor generator via a power split device.

5. The vehicle drive device according to claim 1 , wherein

a main transmission mechanism with a torque converter is provided between an input shaft of the transmission mechanism and an output shaft of the motor generator, and an engine is provided upstream from the motor generator via a clutch.

6. The vehicle drive device according to claim 5 , wherein

the actuation processor causes the connection target gear piece to rotate in the same direction as the direction of the input rotation to the transmission mechanism by dragging torque of the torque converter in response to the range change request, before causing the shift actuator to slide the clutch sleeve.

7. The vehicle drive device according to claim 1 , wherein

the shift actuator includes a shift fork shaft that allows the clutch sleeve to slide, a shift motor that generates rotational power, a power transfer mechanism that moves the shift fork shaft in an axial direction thereof using the rotational power generated by the shift motor, a low range detection element that outputs low range establishment information when a rotation angle of an output shaft of the shift motor reaches an angle at which the clutch sleeve is completely engaged with the low gear piece, and a high range detection element that outputs high range establishment information when the rotation angle of the output shaft of the shift motor reaches an angle at which the clutch sleeve is completely engaged with the high gear piece, and

the determination processor determines whether or not a target range has been established, based on output information from the detection elements, before a predetermined period of time has elapsed since reception of the range change request, and if the result of the determination is negative, determines that the clutch sleeve has become unable to slide.

8. The vehicle drive device according to claim 1 , wherein

the transmission mechanism is a planetary gear set including a sun gear that receives input rotation, a non-rotating ring gear, a plurality of pinion gears provided between and engaged with the sun gear and the ring gear, and a carrier that supports the pinion gears in a manner that allows the pinion gears to rotate freely and is rotated in synchronization with an orbital motion of the pinion gears, and

the carrier is allowed to rotate together with the low gear piece, and the sun gear is allowed to rotate together with the high gear piece.

9. The vehicle drive device according to claim 1 , wherein

the low gear piece is a gear with inner teeth, the high gear piece is a gear with outer teeth and provided inside the low gear piece without making contact with the low gear piece, and the clutch sleeve includes outer teeth that are allowed to engage with the inner teeth of the low gear piece and inner teeth that are allowed to engage with the outer teeth of the high gear piece.