Axial piston pump, and power transmission device with axial piston pump

A power transmission device that is provided within a power transmission path between a power source for traveling of a vehicle and a drive wheel, the power transmission device comprising:

• a drive shaft to which one of an output side and an input side of the power transmission path is connected;
• a driven shaft that is disposed coaxially with the drive shaft, and to which the other one of the output side and input side of the power transmission path is connected;
• a cam device that rotates integrally with the drive shaft;
• a cylinder body that forms therein a cylinder chamber extending in an axial direction of the drive shaft and rotates integrally with the driven shaft;
• a piston that is inserted into the cylinder chamber and reciprocates;
• and
• an axial piston pump that is capable of reciprocating the piston in the axial direction by means of the cam device and discharging fluid suctioned into the cylinder chamber from the cylinder chamber,
• wherein the cam device has:
• a fixed cam member that has a cam surface capable of coming into contact with a cam follower coupled to the piston and is capable of rotating integrally with the drive shaft, with movement of the fixed cam member in the axial direction being restricted;
• a movable cam member that has a cam surface capable of coming into contact with the cam follower and is capable of rotating integrally with the drive shaft, with movement of the movable cam member in the axial direction being allowed;
• and
• a cam effecting device that uses the fluid discharged from the cylinder chamber to change over between a restrained state where the movable cam member is restrained to an effective position with respect to the axial direction, in which the cam follower is capable of following the cam surface of the movable cam member, and a release state where the restraint of the movable cam member to the effective position is released, an irregularity difference in the axial direction of the cam surface of the fixed cam member being smaller than an irregularity difference in the axial direction of the cam surface of the movable cam member, and
• wherein the fixed cam member and the movable cam member are disposed coaxially with the fixed cam member disposed on an innermost side, and an inner circumferential surface of the movable cam member is spline-coupled to an outer circumferential surface of the fixed cam member.