Displacement assembly for a fluid device

A fluid device, comprising:

• a housing defining a fluid inlet and a fluid outlet;
• a displacement assembly in fluid communication with the fluid inlet and the fluid outlet, the displacement assembly including:
• a rotor having a rotation axis about which the rotor selectively rotates and defining a plurality of bores;
• a plurality of reciprocating members in engagement with the plurality of bores of the rotor, each of the reciprocating members having an axial end having a first portion and a second portion;
• a ring assembly defining a cam surface in engagement with the reciprocating members, the ring assembly having a first ring and an axially adjacent second ring, the first ring having a first ring portion defining a first central axis and a bore having an inner surface, the second ring having a second ring portion defining a second central axis and a bore having an inner surface, wherein the first portion of the axial end of each reciprocating member acts against the inner surface of the first ring portion and the second portion of the axial end of the reciprocating member acts against the inner surface of the second ring portion, and wherein the first central axis of the first ring portion is offset from the second central axis of the second ring portions and the rotation axis of the rotor so that the cam surface is defined by an intersection of the first ring portion and the second ring portion.

A variable displacement assembly for use in a rotary fluid device, the variable displacement assembly comprising:

• a rotor having a rotation axis and defining a plurality of bores;
• a plurality of reciprocating members in engagement with the plurality of bores of the rotor, each of the reciprocating members having an axial end having a first portion and a second portion;
• a ring assembly defining a cam surface in engagement with the reciprocating members, the ring assembly having a first ring and an axially adjacent second ring, at least one of the first and second rings being adapted for selective movement relative to the other between a neutral position and a displaced position, the first ring having a first ring portion having at least one displacement ring, the at least one displacement ring defining a central axis and a bore having an inner surface, the second ring having a second ring portion having at least two displacement rings, the at least two displacement rings defining a central axis and a bore having an inner surface, wherein the first portion of the axial end of each reciprocating member acts against one of the inner surface of the at least one displacement ring of the first ring portion and the inner surface of the at least two displacement rings of the second ring portion, wherein the second portion of the axial end of each reciprocating member acts against the other of the inner surface of the at least one displacement ring of the first ring portion and the inner surface of the at least two displacement rings of the second ring portion, and wherein at least one of the central axes of the first and second ring portions is offset from the rotation axis of the rotor in the displaced position so that the cam surface is defined by an intersection of the first ring portion and the second ring portion.

A variable displacement assembly for a fluid device, the variable displacement assembly comprising:

• a rotor defining a plurality of radial bores, the rotor being rotatable about a central axis of rotation;
• a plurality of ring engaging components positioned at each of the bores, the ring engaging components being mounted to radially reciprocate relative to the rotor, the ring engaging components each including a first ring engaging portion and a second ring engaging portion;
• a ring assembly defining a cam surface in engagement with the ring engaging components, the ring assembly having a first ring and a second ring positioned axially adjacent one anther along the axis of rotation of the rotor, the first and second rings extending around the axis of rotation of the rotor, at least one of the first and second rings being adapted for selective movement relative to the other between a neutral position and a displaced position, the first ring having a first ring portion defining a bore having an inner surface, the second ring having a second ring portion defining a bore having an inner surface, wherein the first ring engaging portion of each ring engaging component acts against the inner surface of the first ring portion and the second ring engaging portion of each ring engaging component acts against the inner surface of the second ring portion, wherein the first and second ring portions each define first and second circumferential portions, wherein the first ring engaging portions of the ring engaging components engage the first circumferential portion of the first ring portion and do not engage the second circumferential portion of the first ring portion when the ring assembly is in the displaced position, wherein the second ring engaging portions of the ring engaging components engage the second circumferential portion of the second ring portion and do not engage the first circumferential portion of the second ring portion when the ring assembly is in the displaced position, and wherein in the displaced positon the first circumferential portion of the first ring portion and the second circumferential portion of the second ring portion cooperate to define the cam surface.