# US 12,109,998 B2 · Fail-safe braking system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,109,998 B2 - Document ID: US12109998B2 - Status: Granted - Kind: B2 - Application number: 17/429,578 - Filed: 2020-02-12 - Published: 2022-04-28 - Granted: 2024-10-08 - Earliest claimed: 2019-02-12 - Assignees: Ipgate AG - Applicants: Ipgate AG - Inventors: Anton Van Zanten; Thomas Leiber; Heinz Leiber - Web page: https://patentgrep.com/patent/US12109998B2 ## CPC - B60T 8/885: {using electrical circuitry} - B60T 7/042: {by electrical means, e.g. using travel or force sensors} - B60T 8/409: {characterised by details of the stroke simulating device} - B60T 13/142: {Systems with master cylinder} - B60T 13/145: {Master cylinder integrated or hydraulically coupled with booster} - B60T 2220/04: Pedal travel sensor, stroke sensor; Sensing brake request - B60T 2270/413: Plausibility monitoring, cross check, redundancy - 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 A braking system for a vehicle may include a hydraulic brake pedal system having a master cylinder having at least one pressure chamber, from which a hydraulic output is coupled to at least one brake circuit via an infeed switch valve. The master cylinder is coupled to a reservoir via at least one opening via a hydraulic connection. A failure of a pressure chamber seal of the at least one pressure chamber of the master cylinder is safeguarded by at least one redundancy, and the failure of the pressure chamber seal or the redundancy of the pressure chamber seal of the at least one pressure chamber of the master cylinder can be diagnosed. ## Claims ### Claim 1 A brake system for a vehicle, comprising the following components: one or more hydraulic brake circuits with at least one hydraulically acting wheel brake; at least one pressure supply device, which is connected via a hydraulic line to at least one of the hydraulic brake circuits; and a hydraulic brake pedal system having a single master cylinder with exactly one pressure chamber, a hydraulic output of which is coupled, in a manner switchable by means of an infeed switching valve, to at least one of the hydraulic brake circuits, and wherein the single master cylinder is, by way of at least one opening, coupled by means of a hydraulic connection to a reservoir; wherein a failure of a pressure chamber seal of the pressure chamber of the single master cylinder is safeguarded against by means of at least one redundancy, wherein the redundancy comprises a first throttle and/or a third seal that is redundant with respect to either a primary seal or a secondary seal, wherein failure of the primary seal, failure of the secondary seal, or failure of the third seal of the pressure chamber of the master cylinder is diagnosable, wherein the single master cylinder includes the primary seal, the secondary seal, and the third seal. ### Claim 2 (depends on 1) The brake system as claimed in claim 1, wherein the opening is sealed off by at least the primary seal of the pressure chamber of the master cylinder, and further comprising an open-loop and closed-loop control unit adapted to diagnose failure of the primary seal using pedal travel sensors and a force-travel sensor able to ascertain a pedal force and/or a pressure transducer. ### Claim 3 (depends on 1) The brake system as claimed in claim 1, wherein at least one of the hydraulic connections to the reservoir comprises: the first throttle; the first throttle and a check valve; a second throttle and a switchable solenoid valve; or a switchable solenoid valve. ### Claim 4 (depends on 1) The brake system as claimed in claim 1, wherein the pressure chamber of the hydraulic brake pedal system is connected by means of a hydraulic valve circuit to a travel simulator having at least one pressure chamber, wherein a failure of a pressure chamber seal of the at least one pressure chamber of the travel simulator is safeguarded against by means of at least one further redundancy, and wherein the failure of the pressure chamber seal of the at least one pressure chamber of the travel simulator is diagnosable. ### Claim 5 (depends on 4) The brake system as claimed in claim 4, wherein the at least one pressure chamber of the travel simulator is sealed off by means of a travel simulator seal, wherein the travel simulator seal is the pressure chamber seal of the at least one pressure chamber of the travel simulator, wherein the at least one pressure chamber of the travel simulator has at least one second travel simulator seal that is redundant with respect to the travel simulator seal, and which serves for pressure chamber sealing of the at least one pressure chamber of the travel simulator, wherein the at least one further redundancy comprises the at least one second travel simulator seal. ### Claim 6 (depends on 5) The brake system as claimed in claim 5, wherein the travel simulator has a travel simulator opening between the travel simulator seal and the at least one second travel simulator seal, wherein the travel simulator opening is connected via a third throttle to the reservoir, wherein the at least one further redundancy comprises the at least one second travel simulator seal and the third throttle. ### Claim 7 (depends on 5) The brake system as claimed in claim 5, wherein the open-loop and closed-loop control unit is adapted to diagnose failure of the travel simulator seal. ### Claim 8 (depends on 2) The brake system as claimed in claim 2, further comprising a travel simulator having a pressure chamber with a travel simulator seal, wherein the open-loop and closed-loop control unit is further adapted to diagnose a failure of the travel simulator seal using the force-travel sensor and/or the pressure transducer. ### Claim 9 (depends on 1) The brake system as claimed in claim 1, wherein the hydraulic connection has a parallel circuit of the one throttle and a check valve which closes in the direction of the reservoir. ### Claim 10 (depends on 1) The brake system as claimed in claim 1, wherein the master cylinder has at least one further secondary seal which is redundant with respect to the secondary seal. ### Claim 11 (depends on 10) The brake system as claimed in claim 10, wherein the single master cylinder has a further opening between the secondary seal and the at least one further secondary seal, wherein the further opening is connected via a further throttle to the reservoir. ### Claim 12 (depends on 1) The brake system as claimed in claim 1, wherein the single master cylinder has at least one redundant primary seal that is redundant with respect to the primary seal. ### Claim 13 (depends on 10) The brake system as claimed in claim 10, wherein the hydraulic connection has a switchable solenoid valve. ### Claim 14 (depends on 13) The brake system as claimed in claim 13, wherein the single master cylinder has, between the at least one further secondary seal and the secondary seal, at least one further opening which is connected via a further throttle to the reservoir. ### Claim 15 (depends on 1) The brake system as claimed in claim 1, wherein the single master cylinder has two hydraulic lines to the reservoir, wherein each of the two hydraulic lines has a throttle. ### Claim 16 (depends on 1) The brake system as claimed in claim 1, wherein the single master cylinder has two hydraulic lines to the reservoir; wherein the two hydraulic lines have a throttle and a check valve; or wherein the two hydraulic lines have two throttles and a check valve. ### Claim 17 (depends on 1) The brake system as claimed in claim 1, wherein the opening is further sealed off by at least one secondary seal. ### Claim 18 (depends on 3) The brake system as claimed in claim 3, wherein at least one hydraulic connection to at least one further hydraulic line between the single master cylinder and the reservoir comprises: a throttle; a throttle and a check valve; a further throttle and a switchable solenoid valve; or a switchable solenoid valve. ### Claim 19 (depends on 1) The brake system as claimed in claim 1, wherein the open-loop and closed-loop control unit is adapted to diagnose a failure of the secondary seal, using the pressure supply device.