GB2084275A - Dual-circuit brake systems - Google Patents

Dual-circuit brake systems Download PDF

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Publication number
GB2084275A
GB2084275A GB8128078A GB8128078A GB2084275A GB 2084275 A GB2084275 A GB 2084275A GB 8128078 A GB8128078 A GB 8128078A GB 8128078 A GB8128078 A GB 8128078A GB 2084275 A GB2084275 A GB 2084275A
Authority
GB
United Kingdom
Prior art keywords
dual
brake
circuit
pressure
brake system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8128078A
Other versions
GB2084275B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of GB2084275A publication Critical patent/GB2084275A/en
Application granted granted Critical
Publication of GB2084275B publication Critical patent/GB2084275B/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
    • B60T8/4081—Systems with stroke simulating devices for driver input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
    • B60T13/142—Systems with master cylinder
    • B60T13/145—Master cylinder integrated or hydraulically coupled with booster
    • B60T13/146—Part of the system directly actuated by booster pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
    • B60T13/142—Systems with master cylinder
    • B60T13/147—In combination with distributor valve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/88—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means
    • B60T8/92—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action
    • B60T8/94—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action on a fluid pressure regulator

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)
  • Valves And Accessory Devices For Braking Systems (AREA)

Abstract

A dual-circuit brake system comprises a booster (1) which has two brake valves (5, 6) which are controlled by the pressure of a dual- circuit tandem master cylinder (2). A pedal travel increasing device (12/13) is disposed in the dual-circuit master cylinder (2) in order to give the brake pedal more travel upon commencement of braking and to improve the driver's braking feel. The single device (12/13) is used for the two brake circuits, (I, II), whereby the mode of operation is rendered more reliable. The device (12/13) can be rendered inoperative upon failure of the pressure medium generator (26, 27). Combination into a single structural unit with other valves such as a safety change-overvalves (14, 15), or with anti-skid solenoid valves (16, 17, 18, 19, 20, 21) and with the pressure medium generator (26, 27) is possible. <IMAGE>

Description

SPECIFICATION Dual-circuit brake systems The invention relates to a dual-circuit brake system incorporating a dual-circuit master cylinder and a brake force booster.
In a brake system as known from German Patent specification (Offenlegungsschrift) No.
26 09 905, the booster includes but a single brake valve or control valve for the two circuits, and the pressure introduced into one of the brake circuits by the control valve is then also effective in the other brake circuit. This has the disadvantage that the two brake circuits cannot be boosted in the event of failure of the control valve.
Therefore, brake force boosters have already been equipped with two control valves, each control valve then requiring an individual travel simulator The travel simulator imparts a travel and a reaction to the brake pedal which are related to the brake force. Travel simulation is necessary in order that the driver can apply the brakes in a sensitive manner, and the pressure introduced at any given time by the control valve returns the control valve towards its starting position such that the prevailing forces counterbalance one another. However, considerable costs are involved when travel simulation of this kind has to be duplicated.
A dual-circuit brake system according to the invention comprises a dual-circuit brake force booster which incorporates an individual brake pressure regulating valve for each of the two brake circuits and a pedal-operated dual-circuit master brake cylinder for controlling the two regulating valves which serve to controllably connect a servo-pressure source to the wheel brake cylinders, a single travel simulator common to the two brake pressure regulating valves being provided in the master cylinder.
This has the advantage that the system is less expensive. Furthermore, its weight is reduced.
Moreover, owing to the smaller number of parts, it is less prone to failure than known constructions.
Finally, it is particularly suitably for gn integrated type of construction: the boosting of the brake force, the generation of the pressure, and, if required, also pressure modulation for an anti-skid system are combinable in one structural unit.
The invention is further described, by way of example, with reference to the drawing which is a circuit diagram of a dual-circuit power-assisted brake system in accordance with the invention.
A brake force booster 1 is fitted into a brake system together with a dual-circuit master cylinder 2. Alternatively, however, the two parts 1 and 2 can be separated from one another. Two brake pressure regulating valves 5 and 6 are disposed in the brake force booster 1, and two passages 3 and 4 of two brake circuits I and II lead from the brake force booster 1 to the wheel cylinders.
A first piston 7 for pressurizing a cylinder chamber 7a connected to the brake circuit II is provided in the dual-circuit master cylinder 2, and a second piston 9, which acts against a spring 10 and upon which the piston 7 acts by way of a spring 8, is provided in the cylinder 2 for the purpose of pressurizing a cylinder chamber 9a connected to the brake circuit I. Owing to this arrangement of the pistons one behind the other, a master cylinder 2 of this kind is usually called a "tandem master cylinder". It carries a topping-up reservoir 11.
Each brake pressure regulating valve 5 or 6 incorporates a respective stepped control piston 22 or 23 and the larger rear face of each control piston is exposed to a valve chamber connected to the respective master cylinder chamber 9a or 7a.
The pressure in the master cylinder thereby acts on each control piston to actuate a respective slide valve 24 or 25 which controls the connection between a servo-pressure source and the brake lines 3, 4. The servo-pressure source is a pressure generator which chiefly comprises a pump 27 and an accumulator 26.
The spring 10 of the second master piston 9 does not abut against the housing but against a third piston 1 2 which is also subjected to the force of a spring 1 3 from the rear and the chamber 1 2a containing the spring 13 is in normal operation, connected back to the topping up reservoir 11.
Since the two brake pressure regulating valves 5 and 6 are actuated by the pressure of the master cylinder 2 and since the brake pressure is proportional to the pressure of the master cylinder, the piston 12 and the spring 13 form a travel simulator 1 2/1 3 which is effective for the two brake circuits I and II and which improves the sensitivity experienced by the driver when applying the brakes. In other words, the pedal travel is proportional to the compression of the spring 13 which is proportional to the brake force and to the reaction against the pedal.
Each brake pressure regulating valve 5 or 6 has an associated safety valve 14 or 1 5 respectively by way of which the brake presure medium introduced by the brake pressure regulating valve 5 or 6 normally flows to the wheel brake cylinders and which is responsive to the brake pressure controlled by the respective regulating valve. The safety valve 14 or 1 5 connects the master cylinder directly to the respective brake cylinder of the servo-pressure supply or the respective valve 5 or 6 should fail. Each of the corresponding brake lines 3 and 4 accommodates three solenoid valves 16,17, 18 and 19,20,21 which form part of an anti-skid system 30 which prevents locking of the vehicle wheels when braking by means of wheel sensors (not illustrated) and an electronic control device.
The annular front faces of the control pistons 22, 23 are exposed to the pressure in the spring chamber 1 2a and are therefore normally relieved of pressure. A two-port, two-position valve 28 serving as a monitoring valve is located at the suction side of the pump 27, i.e. in the line connecting the spring chamber 1 2a to the reservoir 11. In the event of failure of the pressure generator 26/27 the valve 28 is displaced into its illustrated position to put the travel simulator 12/13 out of operation. This is achieved in that the piston 12 and the control pistons 22 and 23 become hydraulically locked together. The effect is that the pedal travel becomes directly related to the brake travel and an undesirable change in pedal characteristic is avoided. However, if the pressure generator 26/27 is functioning, the monitoring valve 28 assumes its other position, so that the travel simulator 12/13 can operate.
The dual-circuit brake having only a single travel simulator is simpler than the known dualcircuit brakes. The smaller expense also reduces the weight. The operational reliability is increased.

Claims (9)

1. A dual-circuit brake system comprising a dual-circuit brake force booster which incorporates an individual brake pressure regulating valve for each of the two brake circuits and a pedal-operateddual-ciycuit master brake cylinder for controlling the two regulating valves which serve to controllably connect a servopressure source to the wheel brake cylinders, a single travel simulator common to the two brake pressure regulating valves being provided in the master cylinder.
2. A dual-circuit brake system as claimed in claim 1, in which a single monitoring valve responsive to the pressure of the servo-pressure source is provided for locking the common travel simulator.
3. A dual-circuit brake system as claimed in claim 2, in which each regulating valve has a stepped control piston whose larger rear face is connected to a respective chamber of the master cylinder and whose smaller annular face is connected to the common travel simulator.
4. A dual-circuit brake system as claimed in claim 1, 2 or 3, in which the travel simulator comprises a spring and a free piston acting on the spring, the free piston being exposed to the master cylinder pressure.
5. A dual-circuit brake system as claimed in any of claims 1 to 4, in which a separate changeover safety valve responsive to brake pressure is provided for each brake pressure regulating valve.
6. A dual-circuit brake system as claimed in any preceding claim, which further comprises anti-skid solenoid valves.
7. A dual-circuit brake system as claimed in any preceding claim, in which the servo-pressure source comprises a pressure generator.
8. A dual-circuit brake system-as claimed in any preceding claim, in which the dual-circuit master brake cylinder together with the brake force booster and other components, such as changeover safety valves and anti-skid solenoid valves and pressure generator, are combined to form a structural unit.
9. A dual-circuit brake system constructed and adapted to operate substantially as herein described with reference to and as illustrated in the drawing.
GB8128078A 1980-09-20 1981-09-17 Dual-circuit brake systems Expired GB2084275B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19803035576 DE3035576A1 (en) 1980-09-20 1980-09-20 DUAL CIRCUIT BRAKE AMPLIFIER

Publications (2)

Publication Number Publication Date
GB2084275A true GB2084275A (en) 1982-04-07
GB2084275B GB2084275B (en) 1984-09-05

Family

ID=6112467

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8128078A Expired GB2084275B (en) 1980-09-20 1981-09-17 Dual-circuit brake systems

Country Status (3)

Country Link
JP (1) JPS5784249A (en)
DE (1) DE3035576A1 (en)
GB (1) GB2084275B (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2161562A (en) * 1984-07-12 1986-01-15 Teves Gmbh Alfred Brake system
US4708404A (en) * 1985-01-23 1987-11-24 Alfred Teves Gmbh Hydraulic brake system with hydraulic brake force boosting
FR2600958A1 (en) * 1986-07-04 1988-01-08 Teves Gmbh Alfred HYDRAULIC BRAKING SYSTEM FOR MOTOR VEHICLE
US4730877A (en) * 1985-07-25 1988-03-15 Alfred Teves Gmbh Brake system with hydraulic brake force boosting and pedal travel simulator
US4865398A (en) * 1987-05-29 1989-09-12 Aisin Seiki Kabushiki Kaisha Actuator for wheel anti-lock system
WO1997010133A1 (en) * 1995-09-15 1997-03-20 Itt Automotive Europe Gmbh Hydraulic braking system for motor vehicles
US6311492B1 (en) 1999-02-18 2001-11-06 Tokico Ltd. Master cylinder
DE4322182B4 (en) * 1993-07-03 2005-02-03 Robert Bosch Gmbh Hydraulic power brake system with emergency brake cylinder

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3247497A1 (en) * 1982-12-22 1984-06-28 Alfred Teves Gmbh, 6000 Frankfurt HYDRAULIC TWO-CIRCUIT BRAKE SYSTEM
DE3247496A1 (en) * 1982-12-22 1984-06-28 Alfred Teves Gmbh, 6000 Frankfurt HYDRAULIC TWO-CIRCUIT BRAKE SYSTEM
DE3424912A1 (en) * 1984-07-06 1986-01-16 Alfred Teves Gmbh, 6000 Frankfurt Electronically controlled brake-actuating system
DE3426456C2 (en) * 1984-07-18 1994-06-16 Teves Gmbh Alfred Brake system with slip control
DE3502018C2 (en) * 1985-01-23 1995-09-07 Teves Gmbh Alfred Hydraulic brake system with hydraulic brake booster
DE3511533A1 (en) * 1985-03-29 1986-10-09 Alfred Teves Gmbh, 6000 Frankfurt BRAKE SYSTEM FOR MOTOR VEHICLES
DE3505410A1 (en) * 1985-02-16 1986-08-21 Alfred Teves Gmbh, 6000 Frankfurt Hydraulic brake system
DE3511535A1 (en) * 1985-03-29 1986-10-09 Alfred Teves Gmbh, 6000 Frankfurt BRAKE SYSTEM FOR MOTOR VEHICLES
DE3511972A1 (en) * 1985-04-02 1986-10-09 Daimler-Benz Ag, 7000 Stuttgart PRESSURE MODULATOR DEVICE FOR BRAKING REINFORCEMENT AND ANTI-BLOCKING CONTROL
DE3538284A1 (en) * 1985-10-28 1987-04-30 Teves Gmbh Alfred Hydraulic brake system, especially for motor vehicles
DE3842699C2 (en) * 1988-12-19 1997-04-17 Teves Gmbh Alfred Anti-lock hydraulic brake system
JP3932692B2 (en) 1998-03-10 2007-06-20 アイシン精機株式会社 Vehicle brake device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2161562A (en) * 1984-07-12 1986-01-15 Teves Gmbh Alfred Brake system
US4708404A (en) * 1985-01-23 1987-11-24 Alfred Teves Gmbh Hydraulic brake system with hydraulic brake force boosting
US4730877A (en) * 1985-07-25 1988-03-15 Alfred Teves Gmbh Brake system with hydraulic brake force boosting and pedal travel simulator
FR2600958A1 (en) * 1986-07-04 1988-01-08 Teves Gmbh Alfred HYDRAULIC BRAKING SYSTEM FOR MOTOR VEHICLE
US4865398A (en) * 1987-05-29 1989-09-12 Aisin Seiki Kabushiki Kaisha Actuator for wheel anti-lock system
DE4322182B4 (en) * 1993-07-03 2005-02-03 Robert Bosch Gmbh Hydraulic power brake system with emergency brake cylinder
WO1997010133A1 (en) * 1995-09-15 1997-03-20 Itt Automotive Europe Gmbh Hydraulic braking system for motor vehicles
US6311492B1 (en) 1999-02-18 2001-11-06 Tokico Ltd. Master cylinder

Also Published As

Publication number Publication date
DE3035576A1 (en) 1982-05-06
JPS5784249A (en) 1982-05-26
GB2084275B (en) 1984-09-05

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee