Braking system for a vehicle, method for operating a braking system of a vehicle, and manufacturing method for a braking system for a vehicle

• US 20160129897A1
• Filed: 11/04/2015
• Published: 05/12/2016
• Est. Priority Date: 11/07/2014
• Status: Active Application

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: FEINAUER, Jochen, Willmann, Karl-Heniz, Strengert, Stefan
• Granted Patent: US 10,266,165 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 17/22 Devices for monitoring or checking brake systems; Signal devices
• CPC Class Codes: B60T 2270/402 Back-up
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/1766 Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle
• CPC Class Codes: B60T 8/26 characterised by producing differential braking between front and rear wheels using electrical circuitry or regulation means B60T8/17
• CPC Class Codes: B60T 8/268 using the valves of an ABS, ASR or ESP system
• CPC Class Codes: B60T 8/4072 Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking

Abstract

A braking system for a vehicle includes: a front axle wheel brake cylinder; a rear axle wheel brake cylinder; and a control electronics system for controlling a first brake pressure in the front axle wheel brake cylinder and/or a second brake pressure in the rear axle wheel brake cylinder. A limiting value z-critical is defined for the braking system, which specifies a maximum braking action, at which a traction stress on the front axle of the vehicle and a traction stress on the rear axle of the vehicle are equal. The braking system is mechanically configured for a z-critical of at least 0.7 g, and the braking system is controlled by the control electronics system during operation using a z-critical value of at most 0.7 g.

Claims

1. A braking system for a vehicle, comprising:

at least one front axle wheel brake cylinder, in which at least one first brake pressure is built up to exert a front axle braking torque at least one of on a front axle of the vehicle and on at least one wheel of the front axle;

at least one rear axle wheel brake cylinder, in which at least one second brake pressure is built up to exert a rear axle braking torque at least one of on a rear axle of the vehicle and on at least one wheel of the rear axle; and

a control electronics system configured to activate at least one hydraulic component of the braking system in such a way that at least one of the at least one first brake pressure in the at least one front axle wheel brake cylinder and at least one second brake pressure in the at least one rear axle wheel brake cylinder is variable;

wherein a limiting value z-critical is defined for the braking system, the limiting value z-critical specifying a maximum braking action at which a traction stress on the front axle of the vehicle and a traction stress on the rear axle of the vehicle are equal, and wherein the braking system is mechanically configured for a z-critical value of at least 0.7 g, and wherein the braking system is controlled by the control electronics during operation using a z-critical value of at most 0.7 g.

2. The braking system as recited in claim 1, wherein the at least one front axle wheel brake cylinder is situated in a front axle brake circuit connected to a master brake cylinder of the braking system, and the at least one rear axle wheel brake cylinder is situated in a rear axle brake circuit, and the rear axle brake circuit is configured to be selectably disconnectable from the master brake cylinder via closing of a separating valve.

3. The braking system as recited in claim 2, wherein the rear axle brake circuit is connected via a suction line to a brake fluid reservoir of the braking system, and at least one pump of the rear axle brake circuit is activated with the aid of the control electronics system in such a way that brake fluid is pumped with the aid of the at least one pump of the rear axle brake circuit out of the brake fluid reservoir into the at least one rear axle wheel brake cylinder of the rear axle brake circuit.

4. The braking system as recited in claim 1, wherein the braking system includes a brake booster, and in the event of a functional impairment of at least one of the at least one hydraulic component of the braking system and the control electronics system, the brake booster is activated in such a way that at least one of the at least one first brake pressure in the at least one front axle wheel brake cylinder and the at least one second brake pressure in the at least one rear axle wheel brake cylinder is increased.

5. The braking system as recited in claim 1, wherein the braking system is mechanically configured for a z-critical value of at least 0.8 g.

6. The braking system as recited in claim 5, wherein the braking system is mechanically configured for a z-critical value of at least 0.9 g.

7. The braking system as recited in claim 1, wherein the braking system is controlled using the control electronics system during operation using a z-critical value of at most 0.6 g.

8. The braking system as recited in claim 7, wherein the braking system is controlled using the control electronics system during operation using a z-critical value of at most 0.5 g.

9. A method for operating a braking system of a vehicle, for which a limiting value z-critical is defined, the limiting value z-critical specifying a maximum braking action at which a traction stress on a front axle of the vehicle and a traction stress on a rear axle of the vehicle are equal, the braking system being mechanically configured for a z-critical value of at least 0.7 g, the method comprising:

operating the braking system at least in a normal mode of the braking system using a z-critical of at most 0.7 g to (i) apply a first brake pressure in at least one front axle wheel brake cylinder to exert a front axle braking torque on at least one of the front axle and at least one wheel of the front axle, and (ii) apply a second brake pressure in at least one rear axle wheel brake cylinder to exert a rear axle braking torque on at least one of the rear axle and at least one wheel of the rear axle; and

varying at least one of the first brake pressure in the at least one front axle wheel brake cylinder and the second brake pressure in the at least one rear axle wheel brake cylinder with the aid of at least one hydraulic component of the braking system.

10. The method as recited in claim 9, wherein the at least one second brake pressure in the at least one rear axle wheel brake cylinder is varied by (i) disconnecting a rear axle brake circuit having the at least one rear axle wheel brake cylinder from a master brake cylinder of the braking system by closing of a separating valve, and (ii) pumping brake fluid with the aid of at least one pump of the rear axle brake circuit from a brake fluid reservoir of the braking system into the at least one rear axle wheel brake cylinder of the rear axle brake circuit.

11. The method as recited in claim 10, wherein in the event of a functional impairment of the at least one hydraulic component of the braking system, a brake booster of the braking system is activated to increase at least one of (i) the at least one first brake pressure in the at least one front axle wheel brake cylinder and (ii) the at least one second brake pressure in the at least one rear axle wheel brake cylinder.

12. A manufacturing method for a braking system for a vehicle, comprising:

providing at least one front axle wheel brake cylinder, in which at least one first brake pressure is built up to exert a front axle braking torque at least one of on a front axle of the vehicle and on at least one wheel of the front axle;

providing at least one rear axle wheel brake cylinder, in which at least one second brake pressure is built up to exert a rear axle braking torque at least one of on a rear axle of the vehicle and on at least one wheel of the rear axle; and

providing a control electronics system configured to activate at least one hydraulic component of the braking system in such a way that at least one of the at least one first brake pressure in the at least one front axle wheel brake cylinder and at least one second brake pressure in the at least one rear axle wheel brake cylinder is variable;

wherein a limiting value z-critical is defined for the braking system, the limiting value z-critical specifying a maximum braking action at which a traction stress on the front axle of the vehicle and a traction stress on the rear axle of the vehicle are equal, and wherein the braking system is mechanically configured for a z-critical value of at least 0.7 g, and wherein the braking system is controlled by the control electronics during operation using a z-critical value of at most 0.7 g, and wherein the control electronics system is configured to control the braking system during operation using a z-critical value of at most 0.7 g.

13. The manufacturing method as recited in claim 12, wherein the at least one front axle wheel brake cylinder is situated in a front axle brake circuit connected to a master brake cylinder of the braking system, and the at least one rear axle wheel brake cylinder is situated in a rear axle brake circuit, which is connected via a separating valve to the master brake cylinder, and the rear axle brake circuit is connected via a suction line to a brake fluid reservoir of the braking system and is equipped with at least one pump for pumping brake fluid from the brake fluid reservoir into the at least one rear axle wheel brake cylinder of the rear axle brake circuit.

14. The manufacturing method as recited in claim 12, wherein a brake booster of the braking system is configured in such a way that, in the event of a functional impairment of the at least one hydraulic component of the braking system, at least one of (i) the at least one first brake pressure in the at least one front axle wheel brake cylinder and (ii) the at least one second brake pressure in the at least one rear axle wheel brake cylinder is increased with the aid of the activated brake booster.