IP Library › Granted Patent US 12703340
Granted Patent B2
US 12703340 · App. 18/864,734 · Granted Aug 11, 2026

Electrohydraulic actuator for a brake system

Inventors: Alice Schacherl (Burgberg, DE); Ben Ferguson (Rettenberg, DE); Bernd Lutz (Kempten, DE); Christoph Voelkel (Waltenhofen, DE); Guenter Escher (Oberstdorf, DE); Ignaz Hatt (Buchenberg, DE); Martin Winkler (Sonthofen, DE); Sven Langhorst (Kempten, DE)
Assignee: ROBERT BOSCH GMBH
B60T13/745B60T2270/82
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Quick Facts
Patent No.
US 12703340
App. No.
18/864,734
Granted
Aug 11, 2026
Kind
B2
Abstract

An electrohydraulic actuator for a brake system. The actuator includes: a housing defining an interior space and having first and second openings; a master brake cylinder positioned in the first opening and attached to the housing so that the first opening is sealed in a fluid-tight manner; an electric motor arranged on the housing; and a transmission in the interior space and kinematically coupled to the master brake cylinder. The transmission includes a transmission intermediate part which is moveable along a longitudinal axis and subdivides the housing, into a first housing region in which the master brake cylinder is arranged, and a second housing region facing the second opening. The actuator includes a compensating membrane closing the second opening in a fluid-tight manner and elastically deformable to reduce a pressure difference between the first and second housing region when an axial displacement of the transmission intermediate part occurs.

Claims (26)

1 . An electrohydraulic actuator for a brake system, comprising:

a housing which defines an interior space and has a first opening and a second opening;

a master brake cylinder which is positioned in the first opening and is attached to the housing in such a way that the first opening is sealed in a fluid-tight manner;

an electric motor arranged on the housing;

a transmission which is accommodated in the interior space of the housing and is kinematically coupled to the master brake cylinder, wherein the transmission includes a transmission intermediate part which can be moved along a longitudinal axis and subdivides the housing, in relation to the longitudinal axis, into a first housing region, in which the master brake cylinder is arranged, and a second housing region, which faces the second opening; and

a compensating membrane which closes the second opening in a fluid-tight manner and is elastically deformable in order to reduce a pressure difference between the first housing region and the second housing region in the event of an axial displacement of the transmission intermediate part, wherein the compensating membrane is a closed body, without a passage opening connecting the interior space of the housing with a surrounding area.

2 . The actuator according to claim 1 , wherein the compensating membrane includes a flange portion which abuts against the housing in a region of the second opening, and a curved portion which projects from the housing.

3 . The actuator according to claim 1 , wherein the compensating membrane is made of a plastics material.

4 . The actuator according to claim 3 , wherein the plastics material is ethylene propylene diene monomer.

5 . The actuator according to claim 1 , wherein the transmission includes an actuating part which can be moved along the longitudinal axis and is kinematically coupled to the master brake cylinder, and a guide part which is coupled to the actuating part and is guided along the longitudinal axis, wherein the guide part forms the transmission intermediate part.

6 . The actuator according to claim 1 , further comprising:

an electrical interface in signal connection with the electric motor to connect the electric motor to a voltage source and/or to receive control signals for operating the electric motor, wherein the actuator can be operated exclusively via signals received at the interface without a mechanical substitute actuating interface.

7 . An electrohydraulic actuator for a brake system, comprising:

a housing which defines an interior space and has a first opening and a second opening;

a master brake cylinder which is positioned in the first opening and is attached to the housing in such a way that the first opening is sealed in a fluid-tight manner;

an electric motor arranged on the housing;

a transmission which is accommodated in the interior space of the housing and is kinematically coupled to the master brake cylinder, wherein the transmission includes a transmission intermediate part which can be moved along a longitudinal axis and subdivides the housing, in relation to the longitudinal axis, into a first housing region, in which the master brake cylinder is arranged, and a second housing region, which faces the second opening; and

a compensating membrane which closes the second opening in a fluid-tight manner and is elastically deformable in order to reduce a pressure difference between the first housing region and the second housing region in the event of an axial displacement of the transmission intermediate part, wherein the transmission includes an actuating part which can be moved along the longitudinal axis and is kinematically coupled to the master brake cylinder, and a guide part which is coupled to the actuating part and is guided along the longitudinal axis, wherein the guide part forms the transmission intermediate part, wherein the actuating part is a threaded spindle, wherein the transmission includes a spindle nut which is in engagement with the threaded spindle, and an input shaft, which is drivable by the electric motor and is in engagement with the spindle nut in order to rotate it about the longitudinal axis.

8 . The actuator according to claim 7 , wherein the guide part is coupled to the threaded spindle in a rotationally fixed manner.

9 . The actuator according to claim 7 , wherein the threaded spindle is movable into at least one axial position, in which the threaded spindle protrudes through the second opening.

10 . An electrohydraulic actuator for a brake system, comprising:

a housing which defines an interior space and has a first opening and a second opening;

a master brake cylinder which is positioned in the first opening and is attached to the housing in such a way that the first opening is sealed in a fluid-tight manner;

an electric motor arranged on the housing;

a transmission which is accommodated in the interior space of the housing and is kinematically coupled to the master brake cylinder, wherein the transmission includes a transmission intermediate part which can be moved along a longitudinal axis and subdivides the housing, in relation to the longitudinal axis, into a first housing region, in which the master brake cylinder is arranged, and a second housing region, which faces the second opening; and

a compensating membrane which closes the second opening in a fluid-tight manner and is elastically deformable in order to reduce a pressure difference between the first housing region and the second housing region in the event of an axial displacement of the transmission intermediate part, wherein the transmission includes an actuating part which can be moved along the longitudinal axis and is kinematically coupled to the master brake cylinder, and a guide part which is coupled to the actuating part and is guided along the longitudinal axis, wherein the guide part forms the transmission intermediate part, wherein the guide part is a disk, which includes on its outer circumference at least one first guide element including a projection, which is in engagement with a second guide element which includes a guide groove of the housing extending in parallel with the longitudinal axis.