# US 9,518,621 B2 · Clutch arrangement comprising a shift piston and a piston housing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,621 B2 - Document ID: US9518621B2 - Status: Granted - Kind: B2 - Application number: 14/440,618 - Filed: 2012-12-21 - Published: 2015-10-15 - Granted: 2016-12-13 - Earliest claimed: 2012-12-21 - Assignees: Volvo Construction Equipment AB - Applicants: Volvo Construction Equipment AB - Inventors: Thomas Andersson - Web page: https://patentgrep.com/patent/US9518621B2 ## CPC - F16D 25/083: {Actuators therefor (F16D25/085 - F16D25/087 take precedence)} - F16D 11/10: with clutching members movable only axially - F16H 63/02: Final output mechanisms therefor; Actuating means for the final output mechanisms - F16H 63/3026: {comprising friction clutches or brakes (band brake actuating mechanisms F16H63/3003)} - F16D 25/061: the clutch having interengaging clutch members - F16D 2011/004: {using an internal or intermediate axially slidable sleeve, coupling both components together, whereby the intermediate sleeve is arranged internally at least with respect to one of the components} - F16D 2300/14: Clutches which are normally open, i.e. not engaged in released state - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - F16H: GEARING ## Abstract A clutch arrangement includes a shift piston and a piston housing. The shift piston is arranged to be displaced in an axial direction relative to the piston housing between at least one gear position and a neutral position. The clutch arrangement also includes a spring element for forcing the shift piston towards the neutral position. The clutch arrangement includes a first return piston and a second return piston arranged on opposite sides of the spring element, and the spring element is accommodated within a recess of the shift piston and is pretensioned between the first return piston and the second return piston. In the neutral position the first return piston is forced by the spring element against a first stop element of the shift piston, defining an end position for the first return piston relative to the shift piston, and the second return piston is forced by the spring element against a second stop element of the shift piston, defining an end position for the second return piston relative to the shift piston. ## Claims ### Claim 1 A clutch arrangement comprising a shift piston and a piston housing, the shift piston being arranged to be displaced in an axial direction relative to the piston housing between at least one gear position and a neutral position, the clutch arrangement further comprising a spring element for forcing the shift piston towards the neutral position, wherein the clutch arrangement comprises a first return piston and a second return piston arranged on opposite sides of the spring element, and the spring element is accommodated within a recess of the shift piston, wherein in the neutral position the first return piston is forced by the spring element against a first stop element of the shift piston, defining an end position for the first return piston relative to the shift piston, and the second return piston is forced by the spring element against a second stop element of the shift piston, defining an end position for the second return piston relative to the shift piston, wherein the spring element is pretensioned between the first return piston and the second return piston such that the shift piston will not be displaced from the neutral position until a three acting upon the shift piston exceeds a pretensioning force of the spring element. ### Claim 2 (depends on 1) A clutch arrangement according to claim 1, wherein the shift piston is hydraulically actuated. ### Claim 3 (depends on 1) A clutch arrangement according to claim 1, wherein the shift piston is arranged to be displaced in an axial direction relative to a first gear and a second gear so that the shift piston has a first axial position in which it meshes with the first gear, a second axial position in which it meshes with the second gear and a third, neutral position. ### Claim 4 (depends on 3) A clutch arrangement according to claim 3, wherein it comprises a first inlet for hydraulic fluid, extending through the piston housing, the hydraulic fluid being arranged for forcing the shift piston towards the first axial position. ### Claim 5 (depends on 3) A clutch arrangement according to claim 3, wherein it comprises a second inlet for hydraulic fluid extending through the piston housing, the hydraulic fluid being arranged for forcing the shift piston towards the second axial position. ### Claim 6 (depends on 3) A clutch arrangement according to claim 3, wherein it comprises a third inlet for hydraulic fluid extending through the piston housing, the hydraulic fluid being fed into the internal recess and being arranged for forcing the shift piston towards the neutral position. ### Claim 7 (depends on 3) A clutch arrangement according, to claim 3, wherein the second return piston abuts against the piston housing when the shift piston has assumed the first axial position. ### Claim 8 (depends on 3) A clutch arrangement according to claim 3, wherein the first return piston abuts against, the piston housing when the shift piston has assumed the second axial position. ### Claim 9 (depends on 3) A clutch arrangement according to claim 3, wherein the first gear and the second gear are of the dog clutch type. ### Claim 10 (depends on 1) A clutch arrangement according to claim 1, wherein the recess extends along the axial direction through the shift piston. ### Claim 11 (depends on 1) A clutch arrangement according to claim 1, wherein each of the first return piston and second return piston is generally cylindrical. ### Claim 12 (depends on 1) A clutch arrangement according to claim 1, wherein each of the first and second return pistons has a section which extends out of the internal recess. ### Claim 13 (depends on 1) A clutch arrangement according to claim 1, wherein the first stop element is constituted by a first locking ring and the second stop element is constituted by a second locking ring, the locking rings (18, 19) being arranged in an internal surface of the internal recess. ### Claim 14 (depends on 1) A clutch arrangement according to claim 1, wherein each of the first return piston and second return piston is formed as a substantially annular element extending substantially along the entire circumference of the shift piston. ### Claim 15 (depends on 1) A vehicle comprising a clutch arrangement according to claim 1.