# US 2014/0360352 A1 · Hydrostatic Axial Piston Machine and Retention Plate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360352 A1 - Document ID: US20140360352A1 - Status: Published application - Kind: A1 - Application number: 14/290,242 - Filed: 2014-05-29 - Published: 2014-12-11 - Earliest claimed: 2013-06-05 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Philipp Sitzler; Stefan Hoppe - Web page: https://patentgrep.com/patent/US20140360352A1 ## CPC - F04B 1/126: Piston shoe retaining means - F04B 1/2078: Swash plates - F04B 27/086: {swash plate} - F04B 27/0882: {piston shoe retaining means} - F04B 27/0886: {Piston shoes} - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) ## Abstract An axial piston machine has a cylinder connected to a shaft and a multiplicity of pistons guided by the cylinder and supported by sliding shoes on a swashplate. Each sliding shoe has a sliding shoe collar and a sliding shoe head, and is held in place in a direction of a contact position by an annular retraction plate. An end face segment of the retraction plate engages an annular surface between the sliding shoe collar and the sliding shoe head, and each sliding shoe collar passes through an associated aperture in the retraction plate and connects to a corresponding piston. A surround is formed in the retraction plates at the head of each sliding shoe, and is configured to fit around an axial segment of a circumference of the sliding shoe head in a direction toward the swashplate. ## Claims ### Claim 1 A hydrostatic axial piston machine, comprising: a cylinder connected to a shaft such that the cylinder conjointly rotates with the shaft; and a multiplicity of pistons guided in the cylinder and supported via sliding shoes on a swashplate, wherein: each of the sliding shoes includes a sliding shoe collar and a sliding shoe head, and is held in a direction of a contact position by an annular retraction plate; an end face segment of the annular retraction plate engages an annular surface between the sliding shoe collar and the sliding shoe head of each of the sliding shoes; the sliding shoe collar of each of the sliding shoes passes through an associated aperture in the annular retraction plate and connects to a corresponding one of the multiplicity of pistons; a surround is formed at each aperture of the annular retraction plate; and each surround fits around an axial segment of a circumference of the sliding shoe head of a corresponding one of the sliding shoes in a direction toward the swashplate. ### Claim 2 (depends on 1) The hydrostatic axial piston machine according to claim 1, wherein each surround extends around more than 50% of an axial length of the sliding shoe head of a corresponding one of the sliding shoes. ### Claim 3 (depends on 1) The hydrostatic axial piston machine according to claim 1, wherein a gap is located between an end face segment of each surround and a sliding surface of the swashplate. ### Claim 4 (depends on 1) The hydrostatic axial piston machine according to claim 1, wherein the annular retraction plate includes a cover on a piston side that extends toward the multiplicity of pistons. ### Claim 5 (depends on 4) The hydrostatic axial piston machine according to claim 4, wherein an axial length of the cover that extends toward the multiplicity of pistons is oriented in accordance with a pivoting angle of the swashplate. ### Claim 6 (depends on 1) The hydrostatic axial piston machine according to claim 1, wherein: each surround is formed on a covering ring; and the covering ring is connected to a base plate of the annular retraction plate. ### Claim 7 (depends on 7) The hydrostatic axial piston machine according to claim 7, wherein the covering ring includes a circumferential shoulder configured to fit around an outer circumference of the base plate of the annular retraction plate. ### Claim 8 (depends on 6) The hydrostatic axial piston machine according to claim 6, wherein the covering ring is screwed, pressed, or latched to the base plate. ### Claim 9 (depends on 8) The hydrostatic axial piston machine according to claim 8, wherein: the covering ring is screwed to the base plate with screws; and the screws are alternately screwed in parallel to an axial axis such that the screws are sunk into the covering ring on a swashplate side and project on a rear side of the base plate. ### Claim 10 (depends on 6) The hydrostatic axial piston machine according claim 6, wherein the covering ring is formed from plastic. ### Claim 11 (depends on 6) The hydrostatic axial piston machine according to claim 6, wherein the covering ring is molded by injection molding. ### Claim 12 (depends on 6) The hydrostatic axial piston machine according to claim 6, wherein the covering ring is a multipart covering ring. ### Claim 13 (depends on 6) The hydrostatic axial piston machine according claim 6, wherein, in a radial direction, the covering ring is wider than the base plate of the annular retraction plate. ### Claim 14 (depends on 1) The hydrostatic axial piston machine according to claim 1, wherein each surround is positioned on a pitch circle and each surround overlaps another surround. ### Claim 15 An annular retraction plate for an axial piston machine, comprising: a multiplicity of apertures, wherein: each aperture is configured to receive a sliding shoe collar; surrounds are formed coaxially with the apertures on a swashplate side of an annular retraction plate; and each surround is configured to fit around an axial length of a sliding shoe head in an installed condition.