# US 2022/0205463 A1 · Hydraulic transmission unit for an actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0205463 A1 - Document ID: US20220205463A1 - Status: Published application - Kind: A1 - Application number: 17/604,136 - Filed: 2019-04-17 - Published: 2022-06-30 - Earliest claimed: 2019-04-17 - Assignees: MetisMotion GmbH - Applicants: MetisMotion GmbH - Inventors: Georg BACHMAIER; Matthias GERLICH; Takeru NEMOTO; Wolfgang ZOELS - Web page: https://patentgrep.com/patent/US20220205463A1 ## CPC - F15B 7/08: Input units; Master units - F15B 7/10: Compensation of the liquid content in a system (F15B7/08 takes precedence) - F15B 7/001: {With multiple inputs, e.g. for dual control} - F15B 7/003: {with multiple outputs} - F15B 7/02: Systems with continuously-operating input and output apparatus - F15B 2211/7107: the output members being mechanically linked - F16D 2025/081: {Hydraulic devices that initiate movement of pistons in secondary cylinders for actuating clutches, i.e. primary cylinders} - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES ## Abstract The invention relates to a hydraulic transmission unit for an actuator, which hydraulic transmission unit can be filled with a hydraulic fluid and has a first and a second chamber which are hydraulically interconnected and of which one is designed as a drive chamber and the other one is designed as an output chamber. At least in the first chamber, a piston is arranged movably along a piston axis, such that this piston subdivides the first chamber into a variable-volume working chamber and a rear-side chamber, the rear-side chamber being delimited at least partially by a bellows element having a variable axial length. The invention further relates to an actuator having such a hydraulic transmission unit. ## Claims ### Claim 1 A hydraulic transmission unit for an actuator device, which hydraulic transmission unit can be filled with hydraulic fluid, comprising: a first and a second chamber, which are hydraulically connected to each other and of which one is formed as a drive chamber and the other is formed as an output chamber, wherein a piston is arranged movably along a piston axis at least in the first chamber such that this piston separates the first chamber into a variable-volume working chamber and a rear-side chamber, wherein the rear-side chamber is at least partially delimited by a bellows element with variable axial length. ### Claim 2 (depends on 1) The hydraulic transmission unit according to claim 1, in which the piston comprises a piston body and a piston pin, and in which the associated rear-side chamber comprises an end plate in its axial end region facing away from the piston body, through which the piston pin protrudes into the rear-side chamber and to which the piston pin is fixedly connected. ### Claim 3 (depends on 1) The hydraulic transmission unit according to claim 1, in which the first chamber is configured such that upon a movement of the piston along the piston axis, a volume compensation is effected by the bellows element for the volume of the rear-side chamber. ### Claim 4 (depends on 1) The hydraulic transmission unit according to claim 1, in which the rear-side chamber is fluid-tightly encapsulated against the outer environment. ### Claim 5 (depends on 1) The hydraulic transmission unit according to claim 1, in which the bellows element is formed as a corrugated bellows and/or as a diaphragm bellows. ### Claim 6 (depends on 1) The hydraulic transmission unit according to claim 1, in which the first chamber is laterally delimited by a cylinder wall, wherein the associated piston is arranged axially movably in relation to the cylinder wall, and wherein a gap with a gap width below 10 μm is formed between the cylinder wall and the piston. ### Claim 7 (depends on 1) The hydraulic transmission unit according to claim 1, which is filled with a hydraulic fluid. ### Claim 8 (depends on 1) The hydraulic transmission unit according to claim 1, which additionally comprises a reservoir chamber for the hydraulic fluid, which is fluidically coupled and/or capable of being fluidically coupled to the at least one rear-side chamber. ### Claim 9 (depends on 8) The hydraulic transmission unit according to claim 8, in which the reservoir chamber can be applied with pressure. ### Claim 10 (depends on 1) The hydraulic transmission unit according to claim 1, which is formed as a pumpable transmission unit, such that a summed movement can be generated in the region of the output chamber by multiple consecutive single movements in the region of the drive chamber. ### Claim 11 (depends on 1) The hydraulic transmission unit according to claim 1, which is formed to transfer a movement of a drive body arranged in the region of the drive chamber to an output body arranged in the region of the output chamber with a transmission ratio of 1:2 or less. ### Claim 12 (depends on 1) The hydraulic transmission unit according to claim 1, which is formed to transfer a movement of a drive body arranged in the region of the drive chamber to an output body arranged in the region of the output chamber with a transmission ratio of at least 2. ### Claim 13 (depends on 1) The hydraulic transmission unit according to claim 1, in which a second piston is arranged movably along a piston axis in the second chamber such that this second piston separates the second chamber into a variable-volume second working chamber and a second rear-side chamber, wherein the second rear-side chamber is at least partially delimited by a second bellows element with variable axial length. ### Claim 14 (depends on 1) An actuator device with an actuator and a hydraulic transmission unit according to claim 1, mechanically connected in series with the actuator. ### Claim 15 (depends on 14) The actuator device according to claim 14, which comprises two partial systems, wherein each partial system comprises an actuator and a hydraulic transmission unit mechanically connected in series with the actuator, wherein the two transmission units can be mechanically coupled to a common superordinated output element in the region of their respective output chambers, such that a simultaneous control of the two actuators results in a common movement of the superordinated output element the two hydraulic transmission units.