# US 8,783,792 B2 · Electromechanical brake booster > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,783,792 B2 - Document ID: US8783792B2 - Status: Granted - Kind: B2 - Application number: 12/736,694 - Filed: 2009-03-10 - Published: 2011-03-03 - Granted: 2014-07-22 - Earliest claimed: 2008-04-30 - Assignees: Robert Bosch GmbH - Applicants: Herbert Vollert; Jochen Mayer - Inventors: Herbert Vollert; Jochen Mayer - Web page: https://patentgrep.com/patent/US8783792B2 ## CPC - B60T 13/745: {acting on a hydraulic system, e.g. a master cylinder} - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES ## Abstract The invention relates to an electromechanical brake booster with an electric motor and a helical gearing. The brake booster is used for coupling an auxiliary force via a driver into a piston rod. The invention proposes connecting a spindle of the helical gearing elastically via a spring element to the piston rod such that, in the event of rapid actuation of the brake, the helical gearing and a rotor of the electric motor do not have to be accelerated entirely muscle power. The muscle power required for actuating a brake is reduced as a result in the event of a rapid actuation of the brake. ## Claims ### Claim 1 An electromechanical brake booster, having: a piston rod for transmitting an actuation force from a brake pedal to a piston of a master cylinder; and an electromechanical auxiliary force generator with which an auxiliary force for boosting the actuation force can be generated, wherein a power takeoff element of the auxiliary force generator is directly connected to the piston rod by an elastic element, the elastic element configured to apply an elastic force to said power takeoff element to pull said power takeoff element toward said piston rod. ### Claim 2 (depends on 1) The electromechanical brake booster as defined by claim 1, wherein the elastic element is a spring element. ### Claim 3 (depends on 2) The electromechanical brake booster as defined by claim 2, wherein the brake booster has a slaving device which transmits the auxiliary force of the auxiliary force generator to the piston rod independent of the elastic element. ### Claim 4 (depends on 3) The electromechanical brake booster as defined by claim 3, wherein the auxiliary force generator has an electric motor and a rotation/translation conversion gear. ### Claim 5 (depends on 2) The electromechanical brake booster as defined by claim 2, wherein the auxiliary force generator has an electric motor and a rotation/translation conversion gear. ### Claim 6 (depends on 2) The electromechanical brake booster as defined by claim 2, wherein said spring element includes a helical spring with one end attached to said power takeoff element and an opposite end attached to said piston rod. ### Claim 7 (depends on 1) The electromechanical brake booster as defined by claim 1, wherein the brake booster has a slaving device which transmits the auxiliary force of the auxiliary force generator to the piston rod independent of the elastic element. ### Claim 8 (depends on 7) The electromechanical brake booster as defined by claim 7, wherein the auxiliary force generator has an electric motor and a rotation/translation conversion gear. ### Claim 9 (depends on 1) The electromechanical brake booster as defined by claim 1, wherein the auxiliary force generator has an electric motor and a rotation/translation conversion gear. ### Claim 10 An electromechanical brake booster, having: a piston rod for transmitting an actuation force from a brake pedal to a piston of a master cylinder; an electromechanical auxiliary force generator with which an auxiliary force for boosting the actuation force can be generated, wherein a power takeoff element of the auxiliary force generator is directly connected to the piston rod by an elastic element, wherein the brake booster has a slaving device which transmits the auxiliary force of the auxiliary force generator to the piston rod independent of the elastic element, and wherein the brake booster has a damper which damps a motion of the auxiliary force generator when the damper comes into contact with the slaving device. ### Claim 11 (depends on 10) The electromechanical brake booster as defined by claim 10, wherein the auxiliary force generator has an electric motor and a rotation/translation conversion gear. ### Claim 12 An electromechanical brake booster, having: a piston rod for transmitting an actuation force from a brake pedal to a piston of a master cylinder; an electromechanical auxiliary force generator with which an auxiliary force for boosting the actuation force can be generated, wherein a power takeoff element of the auxiliary force generator is directly connected to the piston rod by an elastic element, wherein the elastic element is a spring element, wherein the brake booster has a slaving device which transmits the auxiliary force of the auxiliary force generator to the piston rod independent of the elastic element, and wherein the brake booster has a damper which damps a motion of the auxiliary force generator when the damper comes into contact with the slaving device. ### Claim 13 (depends on 12) The electromechanical brake booster as defined by claim 12, wherein the auxiliary force generator has an electric motor and a rotation/translation conversion gear. ### Claim 14 An electromechanical brake booster, having: a piston rod for transmitting an actuation force from a brake pedal to a piston of a master cylinder; an electromechanical auxiliary force generator with which an auxiliary force for boosting the actuation force can be generated, the auxiliary force generator including a power takeoff element operable to transmit the auxiliary force; a slaving element disposed between said piston rod and said power takeoff element configured to directly transmit the auxiliary force to said piston rod only when said slaving element is in contact with said power takeoff element; and a connection element directly connected between said power takeoff element and said piston rod and configured to generate an elastic force between said power takeoff element and said piston rod to pull said power takeoff element toward said piston rod when said slaving element is not in contact with said power takeoff element. ### Claim 15 (depends on 14) The electromechanical brake booster as defined by claim 14, wherein said connection element is a spring. ### Claim 16 (depends on 15) The electromechanical brake booster as defined by claim 15, wherein said spring is a helical spring having one end attached to said piston rod and an opposite end attached to said power takeoff element. ### Claim 17 (depends on 14) The electromechanical brake booster as defined by claim 14, wherein: said slaving element includes an annular step defined on said piston rod; and said power takeoff element includes a spindle arranged to contact said annular step to transmit the auxiliary force. ### Claim 18 An electromechanical brake booster, having: a piston rod for transmitting an actuation force from a brake pedal to a piston of a master cylinder; an electromechanical auxiliary force generator with which an auxiliary force for boosting the actuation force can be generated, the auxiliary force generator including a power takeoff element operable to transmit the auxiliary force; a slaving element disposed between said piston rod and said power takeoff element configured to directly transmit the auxiliary force to said piston rod only when said slaving element is in contact with said power takeoff element; and a connection element directly connected between said power takeoff element and said piston rod and configured to generate an elastic force between said power takeoff element and said piston rod when said slaving element is not in contact with said power takeoff element, and further comprising a damper disposed between said slaving element and said power takeoff element. ### Claim 19 (depends on 18) The electromechanical brake booster as defined by claim 18, wherein: said connection element is a tension spring; and said damper is configured to pre-stress said tension spring.