Axial piston device

An axial piston device, comprising:

• a port block;
• a cylinder block that is rotatable relative to the port block;
• and
• a swash plate, wherein
• the port block includes:
• a supply and discharge port surface section with which the cylinder block is configured to come into contact while rotating;
• a first port in a portion of the supply and discharge port surface section which portion is located on a first side of a virtual line passing through a rotation axis of the cylinder block at a right angle;
• and a second port in a portion of the supply and discharge port surface section which portion is located on a second side of the virtual line,
• the cylinder block includes:
• a cylinder port surface configured to come into contact with the supply and discharge port surface section;
• a plurality of cylinder chambers;
• a plurality of pistons provided inside the respective cylinder chambers in such a manner as to be reciprocable along the rotation axis;
• and a plurality of cylinder ports extending from the cylinder port surface to the respective cylinder chambers,
• the swash plate is configured to:
• in response to the cylinder block being driven to rotate, guide the pistons in such a manner as to cause the pistons to be driven to be reciprocated;
• or cause the pistons to be driven to be reciprocated as a result of hydraulic fluid being supplied to or discharged from the cylinder chambers to cause the cylinder block to be driven to rotate,
• the cylinder ports in a phase to face the first port cause the pistons to move in a direction away from the cylinder ports to cause the hydraulic fluid to flow from the first port into the cylinder chambers through the respective cylinder ports,
• the cylinder ports in a phase to face the second port cause the pistons to move toward the cylinder ports to cause the hydraulic fluid to flow out of the cylinder chambers through the respective cylinder ports to the second port,
• the virtual line extends through (i) a first dead center portion that is between the first port and the second port and that is on a first side and (ii) a second dead center portion that is between the first port and the second port and that is on a second side, and
• the supply and discharge port surface section has in at least one of the first dead center portion and the second dead center portion at least one recess extending from a first one of the first port and the second port, the first one being located on a downstream side in a rotation direction of the cylinder block, toward an upstream side in the rotation direction of the cylinder block.