Rotatable piston assembly

A rotatable piston assembly for a reciprocating piston hydraulic machine, wherein the reciprocating piston hydraulic machine is an axial piston machine including:

• a rotating swash mechanism,
• a stationary cylinder block, and
• a rotatable shaft coupled to the rotating swash mechanism,
• the rotatable piston assembly comprising:
• a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston hydraulic machine along a cylinder bore axis of the cylinder bore, where rotation of the rotatable shaft is configured to rotate the rotating swash mechanism, and rotation of the rotating swash mechanism is configured to control a rotation of the rotatable piston about the cylinder bore axis during reciprocation of the rotatable piston in the cylinder bore, the rotatable piston comprising
• a piston lubrication port configured to axially extend between ends of the rotatable piston;
• a pair of piston hydrostatic pockets circumferentially disposed on a sidewall of the rotatable piston, the sidewall disposed between the ends of the rotatable piston;
• a pair of pocket lubrication ports configured to fluidly couple the pair of piston hydrostatic pockets with the piston lubrication port, wherein the pair of piston hydrostatic pockets is configured to counteract and balance forces acting upon the rotatable piston at a piston-cylinder interface when the rotatable piston rotates about the cylinder bore axis, wherein the rotatable piston further comprises an integral valve port in communication with the piston lubrication port of the rotatable piston;
• wherein the rotating swash mechanism is a rotating swashplate comprising a proximal surface,
• the rotatable piston comprises a single sided configuration and a piston constrained joint interface, and
• the rotatable piston assembly further comprising:
• a slipper assembly configured to couple with and constrain rotation of the rotatable piston, the slipper assembly comprising:
• a slipper shoe comprising a distal interface configured to be disposed against a proximal interface of a swashplate, the rotatable piston configured for a controlled rotation with respect to the swashplate,
• a slipper neck proximally extending from the slipper shoe,
• a slipper constrained joint comprising a slipper constrained joint interface configured to be received by the piston constrained joint interface to form a constrained joint,
• a slipper shoe hydrostatic pocket defined by the distal interface of the slipper shoe, and
• a slipper shoe lubrication port in fluid communication with the slipper shoe hydrostatic pocket.