Axial piston pump

Claim 2

In an axial piston machine, particularly in a variabledisplacement axial piston pump, a combination comprising a cylinder barrel having a plurality of cylinder chambers; pistons reciprocably extending into said chambers; a wobble plate adjacent to said pistons; an annular shoulder on each of said pistons and facing away from said plate; drive means for rotating said wobble plate with said barrel; resilient biasing means operatively connected with and arranged to constantly urge all of said pistons toward said wobble plate so that the pistons reciprocate in their chambers in response to rotation and wobbling of said plate, said biasing means comprising a plurality of substantially radially exTending elastic arms each of which surrounds one of said pistons in a region adjacent to the respective shoulder; and compensating members interposed between said arms and the respective shoulders.

Claim 3

A combination as defined in claim 1, wherein each of said arms comprises a cupped end portion and wherein each of said compensating members comprises a spherical portion extending into the respective cupped end portion.

Claim 4

A combination as defined in claim 1, wherein said compensating members are elastic washers movable radially with reference to said pistons.

Claim 5

A combination as defined in claim 1, wherein said arms comprise bifurcated end portions which straddle reduced-diameter portions provided on the respective pistons adjacent to said shoulders.

Claim 6

A combination as defined in claim 1, wherein each of said arms comprises a circumferentially complete annular end portion which surrounds a reduced-diameter portion of the respective piston and wherein each of said compensating members is a circumferentially complete sleeve surrounding the reduced-diameter portion between the corresponding shoulder and the respective annular end portion.

Claim 7

A combination as defined in claim 5 wherein each of said pistons is a composite piston comprising a plurality of separate portions to facilitate the introduction of said reduced-diameter portions through the respective sleeves and annular end portions.

Claim 8

In an axial piston machine, particularly in a variable-displacement axial piston pump, a combination comprising a cylinder barrel having a plurality of cylinder chambers; pistons reciprocably extending into said chambers; a wobble plate adjacent to said pistons; articulate connections interposed between said pistons and said wobble plate, each of said connections comprising a ball having a first portion extending into a socket provided in said wobble plate and a follower having a socket receiving a second portion of the respective ball and abutting with freedom of radial movement against the respective piston; drive means for rotating said wobble plate with said barrel; and resilient biasing means operatively connected with and arranged to constantly urge all of said pistons toward said wobble plate so that the pistons reciprocate in their chambers in response to rotation and wobbling of said plate.

Claim 9

In an axial piston machine, particularly in a variable-displacement axial piston pump, a combination comprising a cylinder barrel having a plurality of cylinder chambers; pistons reciprocably extending into said chambers; a wobble plate adjacent to said pistons; articulate connections interposed between said pistons and said wobble plate, each of said connections comprising a ball having a first portion extending into a socket provided in said wobble plate and a follower having a socket receiving a second portion of the respective ball and abutting with freedom of radial movement against the respective piston; drive means for rotating said wobble plate with said barrel; and resilient biasing means operatively connected with and arranged to constantly urge all of said pistons toward said wobble plate so that the pistons reciprocate in their chambers in response to rotation and wobbling of said plate.

Claim 10

A combination as defined in claim 7, wherein each of said pistons is provided with a flat fixed end face adjacent to and abutting against a complementary flat face of the respective follower.

Claim 11

A combination as defined in claim 8, wherein each of said pistons is provided with a bore extending between said end face thereof and the respective cylinder chamber.

Claim 12

A combination as defined in claim 9, wherein each of said followers is provided with a bore communicating with the socket therein and with the bore of the corresponding piston.

Claim 13

In an axial piston machine, particularly in a variable-displacement axial piston pump, a combination comprising a cylinder barrel having a plurality of cylinder chambers; pistons reciprocably extending into said chambers, each of said pistons being provided with a relatively wide circumferential groove surrounding a smaller-diameter portion of the respective piston; a wobble plate adjacent to said pistons; drive means for rotating said wobble plate into said barrel; resilient biasing means operatively connected with and arranged to constantly urge all of said pistons toward said wobble plate so that the pistons reciprocate in their chambers in response to rotation and wobbling of said plate, said biasing means comprising elastic arms having end portions at least partly surrounding the smaller-diameter portions of said pistons; and sleevelike elastic cushions interposed between said end portions of said arms and shoulders provided on said pistons in said grooves thereof and facing away from said wobble plate.

Claim 14

In an axial piston machine, particularly in a variable-displacement axial piston pump, a combination comprising a cylinder barrel having a plurality of cylinder chambers; pistons reciprocably extending into said chambers, each of said pistons being provided with a relatively wide circumferential groove surrounding a smaller-diameter portion of the respective piston; a wobble plate adjacent to said pistons; drive means for rotating said wobble plate into said barrel; resilient biasing means operatively connected with and arranged to constantly urge all of said pistons toward said wobble plate so that the pistons reciprocate in their chambers in response to rotation and wobbling of said plate, said biasing means comprising elastic arms having end portions at least partly surrounding the smaller-diameter portions of said pistons; and sleevelike elastic cushions interposed between said end portions of said arms and shoulders provided on said pistons in said grooves thereof and facing away from said wobble plate.

Claim 15

A combination as defined in claim 11, wherein each of said cushions is an axiaLly split sleeve which surrounds the respective small-diameter portion with at least some freedom of radial movement with reference to the corresponding piston.