To reduce a load of an actuator for changing over an engaged clutch to a connected state.
There are provided a clutch sleeve having spline teeth and a clutch wheel coaxially arranged on the same axis with the clutch sleeve and having spline teeth. There is provided a clutch for changing over between a connected state and a released state. There is provided an actuator for moving the clutch sleeve in an axial direction to change over the clutch between the connected state and the released state. There is provided a rotational control unit for controlling a motor generator connected to either the clutch sleeve or the clutch wheel and controlling a rotational speed difference between the clutch sleeve and the clutch wheel when the clutch is changed over to the connected state. The spline teeth of the clutch sleeve and the clutch wheel are one-side chamfer engaging teeth provided with a chamfer surface in one rotational direction, and the rotational control unit holds a rotational speed difference between the clutch sleeve and the clutch wheel equal to or more than a threshold (n) set on the basis of an angle of the chamfer surface.
Yoshitaka Kozuka
Akiko Tsutsui