GB2161561A - Multiple-circuit hydraulic brake system - Google Patents

Multiple-circuit hydraulic brake system Download PDF

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Publication number
GB2161561A
GB2161561A GB08514432A GB8514432A GB2161561A GB 2161561 A GB2161561 A GB 2161561A GB 08514432 A GB08514432 A GB 08514432A GB 8514432 A GB8514432 A GB 8514432A GB 2161561 A GB2161561 A GB 2161561A
Authority
GB
United Kingdom
Prior art keywords
brake
wheel brakes
wheel
valve means
pressure
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
GB08514432A
Other versions
GB2161561B (en
GB8514432D0 (en
Inventor
Michael Schorn
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.)
Continental Teves AG and Co oHG
Original Assignee
Alfred Teves 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 Alfred Teves GmbH filed Critical Alfred Teves GmbH
Publication of GB8514432D0 publication Critical patent/GB8514432D0/en
Publication of GB2161561A publication Critical patent/GB2161561A/en
Application granted granted Critical
Publication of GB2161561B publication Critical patent/GB2161561B/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
    • B60T8/88—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
    • 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

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)

Abstract

A multiple-circuit hydraulic brake system, in particular for automotive vehicles equipped with a wheel slip control system, in which allocated to the front wheel brakes (7, 8) are anti-skid valves (11, 14, 16, 19) which permit closure of respective hydraulic connections between master cylinder chambers (5, 6) of a braking pressure generator (1) and the front wheel brakes (7, 8) and to remove pressure fluid from said wheel brakes (7, 8), and in which modulator valves (18, 13) are provided in respective brake lines to rear wheel brakes (9, 10) from servo chamber (2) of the generator (1) and which, upon occurrence of an inadmissible pressure decrease due to a fault in a line to a wheel brake (7, 8) of the front axle, bring about a pressure decrease in the respective diagonally opposite rear- axle wheel brake (9, 10). Throttles (12, 17) associated with the anti- skid valves (11, 16) are arranged separately, in particular spaced apart, from the anti-skid valves (11, 16) and a control port (20, 21) of each modulator valve (18, 13) is connected to a line between the respective throttle (12, 17) and anti-skid valve (11, 16). It is thus ensured in a favourable manner that the modulator valves (18, 13) will respond without delay in the event of an inadmissible pressure drop in the front wheel brakes (7, 8). The valves (18, 13) do not operate during wheel slip control as the control lines are pressurised. <IMAGE>

Description

SPECIFICATION Multiple-circuit hydraulic brake system This invention relates to a multiple-circuit hydraulic brake system, in particular for automotive vehicles equipped with a brake slip control system, in which brake system there are allocated to the wheel brakes first valve means with a throttling function which permit closure of hydraulic connections between a braking pressure generator and the wheel brakes and removal of pressure fluid from the wheel brakes, and in which second valve means are provided which, upon occurrence of an inadmissible pressure drop in a wheel brake of the front axle, bring about a pressure decrease in the respective diagonally opposite wheel brake.
Multiple-circuit hydraulic brake systems of this type are known. In a known brake system of the above-mentioned type the disadvantage arises that, in the event of an inadmissible pressure drop in a wheel brake of the front axle, the throttling effect of the first valve means the pressure in the corresponding working chamber of the braking pressure generator decreases at a considerably lower gradient. As a conseqwence, the second valve means, which in the event of a fail condition occurring at the front axle are to ensure immediate pressure relief of the corresponding wheel brake of the rear axle, are actuated with a delay.The pressure prevailing directly in the wheel brakes of the front axle, however, is unsuitable for actuating the second valve means, because even in an intact brake system a pressure decrease in the front axle occurs during control action which could cause the second valve means to be actuated in an inadmissible way.
Therefore, an object of the present invention is to improve a multiple-circuit hydraulic brake system of the type initially referred to in such a way that in the event of such fail conditions occurring at the front axle the second valve means are actuated without delay and remain inactive during control action.
According to the present invention there is provided a multiple-circuit hydraulic brake system, in particular for automotive vehicles equipped with a brake slip control system, in which brake system there are allocated to the wheel brakes first valve means with a throttling function which permit closure of hydraulic connections between a braking pressure generator and the wheel brakes and removal of pressure fluid from the said wheel brakes, and in which second valve means are provided which, upon occurrence of an inadmissible pressure decrease in a wheel brake of the front axle, bring about a pressure decrease in the respective diagonally opposite rear-axle wheel brake, characterised in that the throttles of the first valve means are arranged separately, in particular in a spatial respect, from the first valve means and that a respective control port of the second valve means is connected between the throttles and the first valve means.
Thus a pressure drop in a wheel brake of the front axle occurring inadmissibly is passed on without substantial delay toward the control port of the second valve means. This causes the second valve means to adopt at equal speed a switch position which brings about a pressure decrease in the diagonally opposite rear wheel brake. A pressure decrease in a wheel brake of the front axle during a brake slip control phase, however, does not influence actuation of the second valve means, since in such operating conditions the first valve means adopt a position in which a hydraulic connection between the wheel brakes and the control ports of the second valve means is interrupted.
It may be provided for example that in the event of an inadmissible pressure drop in a front wheel brake the second valve means increase the volume in the respective diagonally opposite wheel brake. Alternatively, it is feasible that in the event of an inadmissible pressure drop in a front wheel brake the second valve means establish a hydraulic connection between the diagonally opposite wheel brake and an unpressurised supply reservoir.
A favourable improvement of the subject matter of the present application provides that in the event of an inadmissible pressure drop in both front wheel brakes the function of the second valve means is switched off so that the two wheel brakes arranged at the rear axle will be operative in any case in such a fail condition.
An embodiment of the present invention will now be described in more detail with reference to the basic circuit diagram shown in the accompanying drawing.
Reference numeral 1 in the diagram designates a braking pressure generator comprising a hydraulic power booster 2, a tandem master cylinder 3, and a control valve 3' which allows the pressure from a pressure accumulator 22 to be supplied to the pressure (booster) chamber of the booster 2 and a rear-axle brake circuit. The hydraulic brake power booster 2 and the control valve 3' are actuatable by pressurisation of a brake pedal 4.
Numerals 7, 8, 9, 10 in the drawing designate wheel brakes, the wheel brakes 7, 8 preferably being arranged at the front axle of an automotive vehicle and the wheel brakes 9, 10 at the rear axle of the automotive vehicle. The wheel brakes 7, 8 communicate via corresponding hydraulic lines with the working chambers 5, 6 of the tandem master cylinder 3. The rear-axle wheel brakes communicate with the pressure accumulator 22 via a hydraulic line into which the control valve 3' is inserted. The hydraulic booster 2 is supplied with boost pressure from the pressure accumulator 22 via a corresponding hydraulic line.
Two-way/two-position directional control valves 11, 1 6 and throttles 12, 1 7 are inserted in the lines from the master cylinder to the wheel brakes 7, 8. Further two-way/two position directional control valves 14, 1 9 are connected directly at the wheel brakes 7, 8 allowing a pressure relief of the wheel brakes 7, 8 toward an unpressurised supply reservoir 1 5 when actuated by a non-illustrated electronic slip control system. The rear-axle wheel brakes 9, 10 communicate via hydraulic lines with the pressure accumulator 22. Inserted in the joint line is the control valve 3, and a two way/two-position directional control valve 23.
From this line a further line branches off into which a further two-way two-position directional control valve 24 is inserted allowing a pressure relief of the wheel brakes 9, 10 toward an unpressurised reservoir to take place when it is actuated by the electronic slip control system (not shown). Cutoff valves 18, 1 3 are inserted in the branch lines leading to the wheel brakes 9, 10.
The two-way/two-position directional con trol valves 11, 1 j), 19, 16, 23, and 24 are switchable by the non-illustrated electronic slip control system which senses the rotational behaviour of the wheels via corresponding sensors. The cutoff valves 13, 1 8 are hydraulically actuatable by the pressures prevailing between the throttle 12 and the twoway/two-position directional control valve 11, on the one hand, and between the throttle 1 7 and the two-way/two-position directional control valve 16, on the other hand. The cutoff valves 18, 1 3 operate in such a way that in the event of a pressure relief of the control ports 20, 21 a pressure drop is caused in the wheel brakes 9, 10.
The mode of operation of the brake system described will be explained in more detail hereinbelow, starting from the brake's release condition in which all parts shown in the drawing are in the idle position. When an actuating force is exerted on the brake pedal 4, hydraulic pressure is supplied into the hydraulic power booster 2 which in turn pressurises the working chambers 5, 6 of the tandem master cylinder 3. The pressure generated in the working chambers 5, 6 of the tandem master cylinder 3 is fed to the wheel brakes 7, 8. The rear-axle wheel brakes 9, 10 are pressurised directly by the pressure from the pressure accumulator 22.As a result, a pressure is generated at the control ports 20, 21 of the cutoff valves 13, 1 8 causing the cutoff valves 13, 1 8 to adopt a position in which hydraulic connections are established between the wheel brakes 9, 10 and the pressure accumulator 22.
When the non-illustrated electronic slip control system recognises a critical slip value, for instance at the vehicle wheel allocated to the wheel brake 7, the two-way/two-position directional control valve 11 will switch to a locking position so that the pressure in the wheel brake 7 remains constant irrespective of the pressure in the working chamber 6 of the tandem master cylinder 3. In case such a phase of maintaining the pressure constant does not suffice to bring about re-acceleration of the vehicle wheel allocated to the wheel brake 7, the two-way/two-position directional control valve 14 will switch over to an open position so that a hydraulic connection is established between the wheel brake 7 and the unpressurised supply reservoir 15, pressure fluid is removed from the wheel brake 7 and the effective braking pressure in the wheel brake 7 is reduced accordingly.A locking hazard having been averted, the twoway/two-position directional control valves 11, 14 switch back to the position as shown in the drawing. A corresponding control operation takes place when the vehicle wheel allocated to the wheel brake 8 reaches a critical slip value. In such a case the twoway/two-position directional control valves 16, 1 9 are actuated in the same way. During such a control action, the control ports 20, 21 of the cutoff valves 13, 18 are pressurised.
Now a fail condition shall be assumed in which the wheel brake 7 for instance is depressurised. In the event of such a fail condition the electronic slip control system ensures that all two-way/two-position directional control valves 11, 14, 16, 19, 23, and 24 remain in their switch position as shown in the drawing. A pressure drop in the wheel brake 7, on the other hand, will entail the control port 21 of the cutoff valve 13 being depressurised immediately so that a corresponding pressure relief will also take place in the wheel brake 1 0. As a consequence, both wheel brakes 7, 10 will be more or less depressurised and the entire braking force is exerted by the wheel brakes 8, 9 alone. In such a fail condition, therefore, any substantial yawing moments are precluded from influencing the vehicle.
A corresponding operation takes place in the event of the pressure in the wheel brake 8 decreasing to an inadmissibly low level due to a fail condition.
The present invention is described hereinbefore for a triple-circuit brake system in which it is of particular advantage. However, it can also be used with other brake circuit allocations, e.g. diagonal allocation.

Claims (5)

1. A multiple-circuit hydraulic brake system, in particular for automotive vehicles equipped with a brake slip control system, in which brake system there are allocated to the wheel brakes first valve means with a throttling function which permit closure of hydraulic connections between a braking pressure generator and the wheel brakes and removal of pressure fluid from the said wheel brakes, and in which second valve means are provided which, upon occurrence of an inadmissible pressure decrease in a wheel brake of the front axle, bring about a pressure decrease in the respective diagonally opposite rear-axle wheel brake, characterised in that the throttles (12, 17) of the first valve means (11,14,16, 1 9) are arranged separately, in particular in a spatial respect, from the first valve means (11, 14, 16, 1 9) and that a respective control port (20, 21) of the second valve means (18, 13) is connected between the throttles (12, 17) and the first valve means (11, 14, 16, 19).
2. A multiple-circuit hydraulic brake system as claimed in claim 1, characterised in that the second valve means (18, 13), in the event of an inadmissible pressure drop in a front wheel brake (7, 8), will increase the volume in the respective diagonally opposite wheel brake (9, 1 O).
3. A multiple-circuit hydraulic brake system as claimed in claim 1, characterised in that the second valve earns (18, 13), in the event of an inadmissib pressure drop in a front wheel brake (7, 8), will establish a hydraulic connection between the diagonally opposite wheel brake (9, 10) and an unpressurised supply reservoir (15).
4. A multiple-circuit hydraulic brake system as claimed in claim 1, characterised in that, in the event of an inadmissible pressure drop in both front wheel brakes (7, 8), the function of the second valve means (1 8, 1 3) will be switched off.
5. A multiple-circuit hydraulic brake system substantially as herein described with reference to the accompanying drawing.
GB08514432A 1984-06-23 1985-06-07 Multiple-circuit hydraulic brake system Expired GB2161561B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19843423296 DE3423296A1 (en) 1984-06-23 1984-06-23 HYDRAULIC MULTI-CIRCUIT BRAKE SYSTEM

Publications (3)

Publication Number Publication Date
GB8514432D0 GB8514432D0 (en) 1985-07-10
GB2161561A true GB2161561A (en) 1986-01-15
GB2161561B GB2161561B (en) 1988-04-07

Family

ID=6239041

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08514432A Expired GB2161561B (en) 1984-06-23 1985-06-07 Multiple-circuit hydraulic brake system

Country Status (4)

Country Link
DE (1) DE3423296A1 (en)
FR (1) FR2566351B1 (en)
GB (1) GB2161561B (en)
SE (1) SE455686B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2179414A (en) * 1985-08-20 1987-03-04 Teves Gmbh Alfred Slip-controlled brake system for automotive vehicles

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3631684A1 (en) * 1986-09-18 1988-03-24 Teves Gmbh Alfred Hydraulic brake system for motor vehicles
DE10244375B4 (en) * 2002-07-05 2013-08-08 Continental Teves Ag & Co. Ohg Hydraulic vehicle brake system
DE10231020A1 (en) * 2002-07-09 2004-02-05 Continental Teves Ag & Co. Ohg Electronic data systems/address resolution protocol/electronic differential lock braking system for a motor vehicle has a brake-pressure generator, a brake-force booster and controllable valves

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2939602A1 (en) * 1979-09-29 1981-04-16 Robert Bosch Gmbh, 7000 Stuttgart HYDRAULIC MULTI-CIRCUIT BRAKING SYSTEM
JPS5780955A (en) * 1980-11-10 1982-05-20 Toyota Motor Corp Anti-skid device for isolatedly dual rear-brake system
DE3150218A1 (en) * 1981-12-18 1983-07-21 Alfred Teves Gmbh, 6000 Frankfurt HYDRAULIC MULTI-CIRCUIT BRAKE SYSTEM
DE3240404C2 (en) * 1982-11-02 1993-11-11 Teves Gmbh Alfred Hydraulic brake system with slip control

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2179414A (en) * 1985-08-20 1987-03-04 Teves Gmbh Alfred Slip-controlled brake system for automotive vehicles

Also Published As

Publication number Publication date
GB2161561B (en) 1988-04-07
SE8502895D0 (en) 1985-06-12
GB8514432D0 (en) 1985-07-10
SE455686B (en) 1988-08-01
FR2566351B1 (en) 1988-06-24
SE8502895L (en) 1985-12-24
DE3423296A1 (en) 1986-01-02
FR2566351A1 (en) 1985-12-27

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Legal Events

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

Effective date: 19940607