| 主权项 |
1. A power plant that drives left and right wheels of a vehicle, comprising:
a drive source; a differential gear that includes a first rotary element mechanically connected to the drive source, a second rotary element mechanically connected to one of the left and right wheels, and a third rotary element mechanically connected to the other of the left and right wheels; a fluid pressure motor that includes a first pressure chamber and a second pressure chamber which communicate with a fluid pressure supply source for pumping fluid, respectively, and is configured such that fluid pressure is supplied to the first pressure chamber, and the supplied fluid pressure is discharged into the second pressure chamber to thereby apply a positive torque to the third rotary element, and that fluid pressure is supplied to the second pressure chamber, and the supplied fluid pressure is discharged into the first pressure chamber to thereby apply a negative torque to the third rotary element; and a fluid passage switching mechanism that is arranged on a fluid passage communicating between the fluid pressure supply source and the first pressure chamber and on a fluid passage communicating between the fluid pressure supply source and the second pressure chamber, to switch communication and shutoff of the fluid passages, wherein the fluid passage switching mechanism includes: a first member that is provided with a first communication port to which is connected a fluid supply passage communicating with the fluid pressure supply source, a second communication port to which is connected a first fluid passage communicating with the first pressure chamber, a third communication port to which is connected a second fluid passage communicating with the second pressure chamber, and a fourth communication port to which is connected a fluid discharge passage communicating with a reservoir which stores the fluid; and a second member that is provided in a manner movable to a first position, a second position, and a third position, with respect to the first member, for switching communicating states and shut-off states between the first to fourth communication ports, wherein the fluid supply passage, the first fluid passage, the second fluid passage, and the fluid discharge passage form the fluid passages, wherein the fluid passage switching mechanism is configured such that: when the second member is in the first position, the first communication port and the second communication port are placed in a state communicating with each other, the first communication port and the third communication port are placed in a state communicating with each other, the second communication port and the fourth communication port are placed in a state shut off from each other, and the third communication port and the fourth communication port are placed in a state shut off from each other, when the second member is in the second position, the first communication port and the second communication port are placed in the state communicating with each other, the first communication port and the third communication port are placed in a state shut off from each other, the second communication port and the fourth communication port are placed in the state shut off from each other, and the third communication port and the fourth communication port are placed in a state communicating with each other, and when the second member is in the third position, the first communication port and the second communication port are placed in a state shut off from each other, the first communication port and the third communication port are placed in the state communicating with each other, the second communication port and the fourth communication port are placed in a state communicating with each other, and the third communication port and the fourth communication port are placed in the state shut off from each other, and wherein the first member is provided with a plurality of communication port groups, each formed by the first to fourth communication ports. |
