GB2084276A - Brake force booster - Google Patents
Brake force booster Download PDFInfo
- Publication number
- GB2084276A GB2084276A GB8128079A GB8128079A GB2084276A GB 2084276 A GB2084276 A GB 2084276A GB 8128079 A GB8128079 A GB 8128079A GB 8128079 A GB8128079 A GB 8128079A GB 2084276 A GB2084276 A GB 2084276A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pressure
- brake
- valve
- force booster
- brake force
- 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.)
- Withdrawn
Links
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
Abstract
A brake force booster (1) has a multi-circuit brake pressure regulating valve (5, 6) which has a pilot valve (9, 10) provided parallel thereto. The pilot valve (9, 10) is actuated by the accumulator of a pressure generator (24/25). lf the accumulator pressure should drop or should not exist, the pilot valve connects a master cylinder (2) directly to the brake cylinder. When using a brake force booster (1) of this kind in an anti-skid system, a device is provided which, compared with known constructions, is less expensive, has a lower weight and a smaller volume and whose function is improved with respect to noise and the reactive effect on the pedal. The brake force booster is intended for a multi-circuit brake system for motor vehicles. <IMAGE>
Description
SPECIFICATION
Brake force booster
The invention relates to a brake force booster of the type having a brake pressure regulating valve for operable by a master cylinder for connecting a pressure generator to the vehicle wheel brake cylinders. A brake force booster of this kind is described in French Patent Specification No.
A2327 124.
Although this is known brake force booster permits uniform actuation of the brake pressure regulating valves, it is not intended to use it for anti-skid systems.
The present invention provides a brake force booster for a motor vehicle multi-circuit brake system, which brake force booster comprises a multi-circuit brake pressure regulating valve which is operable by the pressure of a master cylinder and which is adapted to effect in the brake circuits a boosting action which is proportional to the pressure in the master cylinder and which is derived from a pressure generator, and a pilot valve which is in parallel with the multi-circuit brake pressure regulating valve and which is actuatable on the one hand by the brake pressure derived from the pressure generator and on the other hand by the pressure in the master cylinder and by which the master cylinder is connectible directly to a wheel cylinder if the pressure from the pressure generator should drop or should not exist.
This has the advantage that the booster is particularly suitable for use in an anti-skid system, it being advantageous that the operation of the anti-skid system results in only a slight reactive effect upon the brake pedal, damage to the master cylinder sealing member cannot occur, only a low power requirement of the pressure generator is necessary, the brake force boosting can be realised in the anti-skid system without additional costs and the pilot valve is of very simple construction and is very reliable in operation, and finally no separate actuating pistons are required, since the actuating piston of the pilot valve undertakes a plurality of switching tasks.
The invention is further described, by way of example, with reference to the drawings, in which: Figure 1 is a rough circuit diagram of one embodiment of brake force booster having valves of an anti-skid system; and
Figure 2 is a more detailed illustration of one of the brake pressure regulating valves of the booster of Figure 1, together with its associated pilot valve.
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 associated respectively with the brake pressure regulating valves 5 and 6.
A respective travel simulator 7 or 8 is provided in parallel with each of the bral < e pressure regulating valves 5 and 6. In this manner, friction losses of the travel simulators are avoided upon actuation of the brake pressure regulating valves 5 and 6 by the master cylinder 2. However, it is also possible to use a conventional master cylinder having a coaxial travel simulator. The purpose of the travel simulators is to impart a travel to the brake pedal which is related to the brake force.
Thus, each travel simulator comprises a piston which is displaced against a travel-simulating spring by the master brake pressure. So long as all brake circuits are intact, the brake pressure regulating valves 5, 6 ensure that the brake pressure is proportional to the master cylinder pressure, whereby the pedal travel is proportional to the brake force.
Each brake pressure regulating valve 5 and 6 has an associated pilot valve 9 or 10 through which the brake pressure medium introduced by the brake pressure regulating valve 5 or 6 fiows to the wheel cylinders when the pressure medium supply is intact. Each brake line 3 and 4 incorporates three solenoid valves 1 3, 14, 1 5 and 1 6, 17, 1 8, respectively which form part of an anti-skid system 1 9 which prevents locking of the vehicle wheels during braking by means of wheel sensors (not illustrated) and an electronic control device.
Each brake pressure regulating valve 5 and 6 includes a respective control piston 20 or 21 which is operable by the pressure in the master cylinder and which actuates a slide valve 22 or 23 which monitors communication between a pressure generator and the brake lines 3, 4. The pressure generator essentially comprises a pump 24 and an accumulator 25.
As may be seen particularly in Figure 2, each pilot valve 9 and 10 has an actuating piston 26 and a differential pressure valve 27, both of which will be considered together with respect to the admission of pressure. The two parts 26 and 27 are subjected on the one hand to the master cylinder pressure PHz fed by way of a respective line 28 or 29 (see aiso Figure 1), and on the other hand, by way of a line 47 to the brake pressure in the line 3 or 4 derived from the accumulator pressure of the pressure generator 24/25, although this brake pressure only acts upon the differential pressure valve 27.
The actuating piston 26 of the pilot valve 9 or 10 has a piston surface 30 which is exposed to a relief chamber 31 connected by way of a return line 32 to the topping-up reservoir of the master cylinder 2. A pin 33 mounted on the piston surface 30 can actuate a warning switch 34.
Furthermore, an arm 35 is secured to the piston surface 30 and, by means of a respective push rod 36 and 37, can actuate a non-return valve 38 and, in the opposite direction thereto, a leakage valve 39. The leakage valve 39 is located in a line 40 which leads from the spring chambers of the travel-simulators 7 and 8 and to which are connected lines 41 leading from the brake pressure regulating valves 5 and 6.
The actuating piston 26 has an annular surface 42 which defines a chamber 43 which is connected to the pressure generator 24/25 by way of a pressure line 44 (not shown in Figure 1).
Finally, a line portion 46 monitored by a valve slide 45 of the actuating piston 26 leads from the pilot valve 9 or 10 and establishes direct communication between the master cylinder and the wheel cylinders by way of the line 3 or 4 by displacement of the valve slide 45 to the left by a spring 48 in the absence of pressure in the chamber 43.
The master cylinder pressure produced upon actuation of the brake pedal is applied to the control pistons 20, 21 of the brake pressure regulating valves 5 and 6 respectively, the control edge of the slide valve 22 or 23 establishes communication between the brake system and the pressure generator 24/25. The pressure medium is fed into the respective brake line 3 or 4 by way of the pilot valve 9 or 10.
The respective solenoid valves 13, 14, 1 5 and 1 6, 1 7, 18 are fitted as anti-skid valves in each brake circuit I and 11, so that the brake pressure at any given time is monitored with respect to locking of the wheels.
The different diameters of slide valve 22, 23 and control piston 20, 21 are dependent upon the brake force boosting factor desired in any given case. By virtue of the arrangement of a travel simulator 7 or 8 in each brake circuit I and II respectively, a specific pedal characteristic is obtained, such as is necessary, for anthropotechnical reasons, for satisfactory
metering brake pressure to the brakes. In the event of failure of the pressure of the pressure generator, the leakage valve 39 provided in the
line 40 is closed under spring force (spring 48) by
pressure drop in the chamber 43, so that no further pressure loss can occur in the system, the
area of the left hand face of the valve slide 45
being relatively small so that the spring 48 can
overcome any pressure which may be present in
the line 28 or 29.The leakage valve 39 is
connected to the travel simulator 7 or 8, so that
the latter is blocked (i.e. its piston can no longer be
displaced) in order that the full volume
displacement of the master cylinder 2 can be used
to generate brake pressure.
In the construction shown in Figure 2, the left
hand valve slide portion 45 of the actuating piston
26, which is moved to the left by the spring 48
upon failure of pressure, establishes
communication between the master cylinder (line
28) and the wheel cylinder (by way of the line
portion 46 and the line 3 or 4) so that the brakes
can be applied in an unobstructed and non
boosted manner. At the same time, the non-return
valve 38 is opened and the leakage valve 39 is
closed to enable the brake pressure in the lines 3,4 to be relieved via the differential pressure
valve 27 when the brake pedal is released.
Thus, the purpose of the differential pressure valve 27 is to establish equality between the master cylinder pressure and the secondary pressure in the event of failure of the pressure supply. Without this differential pressure valve 27, an unpleasant jolt would be felt on the brake pedal during a braking operation in the event of failure of the pressure supply. Moreover, the seaiing member of the master brake cylinder would be damaged, since it is possible that it will be located precisely in the region of the breather port of the master cylinder particularly when the brake pedal returns to its starting position.
The warning switch 34 responds if the pressure generator 24/25 should fail, so that the drop in the accumulator pressure is indicated. An additional motor for the auxiliary generation of pressure can be switched on by the warning switch.
Claims (14)
1. A brake force booster for a motor vehicle multi-circuit brake system, which brake force booster comprises a multi-circuit brake pressure regulating valve which is operable by the pressure of a master cylinder and which is adapted to effect in the brake circuits a boosting action which is proportional to the pressure in the master cylinder and which is derived from a pressure generator, and a pilot valve which is in parallel with the multicircuit brake pressure regulating valve and which is actuatable on the one hand by the brake pressure derived from the pressure generator and on the other hand by the pressure in the master cylinder and by which the master cylinder is connectible directly to a wheel cylinder if the pressure generated should drop or should not exist.
2. A brake force booster as claimed in claim 1, in which the pilot valve is a three-port, twoposition valve and is provided with an actuating piston which is subjected to the pressure in the master cylinder against the force of a spring and with a valve member which monitors communication between the master cylinder and the wheel brake cylinder during movement of the actuating piston.
3. A brake force booster as claimed in claim 2, in which the valve member is a valve slide.
4. A brake booster as claimed in claim 2 or 3, in which the piston of the pilot valve is subjected on the one hand to the pressure in the master cylinder and on the other hand directly to the pressure of the pressure generator.
5. A brake force booster as claimed in claim 2, 3 or 4, in which a warning switch for dropping accumulator pressure and/or an additional motor for the auxiliary generator of pressure are actuatable by the actuating piston.
6. A brake force booster as claimed in any of claims 1 to 5, in which the brake pressure regulating valve is directly actuatable by the pressure in the master cylinder, and a travel simulator is disposed in parallel therewith.
7. A brake force booster as claimed in claim 6, in which an individual travel simulator is provided for each brake circuit.
8. A brake force booster as claimed in claim 7, in which the travel simulator is blockable by means of a valve which is controlled by the pressure of the pressure generator.
9. A brake force booster as claimed in any of claims 1 to 8, in which the pilot valve additionaily has a differential pressure valve which is subjected on the one hand to the brake pressure derived from the pressure generator and on the other hand to the pressure in the master cylinder.
10. A brake force booster as claimed in claim 6, 7, 8 or 9, when dependent from claim 2, in which at least one other valve is actuatable by the actuating piston of the pilot valve for blocking the travel simulator for closing the differential pressure valve, as the case may be.
11. A brake force booster as claimed in claim 10, in which a non-return valve for blocking the travel simulator and a leakage valve located in a return line for closing the differential pressure valve are couplable to the actuating piston.
12. A brake force booster as claimed in any of claims 1 to 11, in which an additional pilot valve and an individual brake pressure regulating valve are provided for each brake circuit.
13. A brake force booster as claimed in any of claims 1 to 12, in which the booster together with the master cylinder, the brake valve and the pressure generator are combined to form a structural unit.
14. A brake force booster as claimed in any of claims 1 to 12, in which the master cylinder is arranged separately from the brake force booster.
1 5. A brake force booster constructed and adapted to operate substantially as herein described with reference to and as illustrated in the drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803035537 DE3035537A1 (en) | 1980-09-20 | 1980-09-20 | BRAKE POWER AMPLIFIER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2084276A true GB2084276A (en) | 1982-04-07 |
Family
ID=6112443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8128079A Withdrawn GB2084276A (en) | 1980-09-20 | 1981-09-17 | Brake force booster |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5784254A (en) |
| DE (1) | DE3035537A1 (en) |
| GB (1) | GB2084276A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2538329A1 (en) * | 1982-12-22 | 1984-06-29 | Teves Gmbh Alfred | BRAKE SYSTEM WITH TWO CIRCUITS WITH BRAKE SLIDER CONTROL, IN PARTICULAR FOR MOTOR VEHICLE |
| EP0388134A1 (en) * | 1989-03-13 | 1990-09-19 | Honda Giken Kogyo Kabushiki Kaisha | Hydraulic braking pressure control system |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61218466A (en) * | 1985-03-25 | 1986-09-27 | Nippon Denso Co Ltd | Antiskid controller |
| JPS6291356A (en) * | 1985-10-18 | 1987-04-25 | Nissan Motor Co Ltd | Brake control device |
| JP2590825B2 (en) * | 1986-07-12 | 1997-03-12 | トヨタ自動車株式会社 | Manual / Electric dual brake system |
| DE3640228A1 (en) * | 1986-11-25 | 1988-05-26 | Teves Gmbh Alfred | Hydraulic dual-circuit brake system for motor vehicles |
-
1980
- 1980-09-20 DE DE19803035537 patent/DE3035537A1/en not_active Ceased
-
1981
- 1981-09-17 GB GB8128079A patent/GB2084276A/en not_active Withdrawn
- 1981-09-18 JP JP14644481A patent/JPS5784254A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2538329A1 (en) * | 1982-12-22 | 1984-06-29 | Teves Gmbh Alfred | BRAKE SYSTEM WITH TWO CIRCUITS WITH BRAKE SLIDER CONTROL, IN PARTICULAR FOR MOTOR VEHICLE |
| EP0388134A1 (en) * | 1989-03-13 | 1990-09-19 | Honda Giken Kogyo Kabushiki Kaisha | Hydraulic braking pressure control system |
| US4995677A (en) * | 1989-03-13 | 1991-02-26 | Honda Giken Kogyo Kabushiki Kaisha | Hydraulic braking pressure control system |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3035537A1 (en) | 1982-05-06 |
| JPH0251788B2 (en) | 1990-11-08 |
| JPS5784254A (en) | 1982-05-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |