JPS63215453A - Hydraulic brake system for car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application, Prior Art] The present invention relates to a hydraulic brake device of the type according to claim 1.

[Conventional technology]

According to West German patent application publication number 2212912,
Vehicle braking systems with anti-locking means are known. This anti-locking means has at least one brake pressure regulator intermediate the brake master cylinder and at least one wheel brake. This brake pressure regulator consists of six coaxially arranged cylinders, six pistons fixedly connected by one hollow two-stone rod, and a return spring that loads the pistons in the direction of the erectile position. , a normally open valve. One cylinder chamber, defined by the piston, is always connected to the brake master cylinder, and another cylinder chamber is always in communication with at least one of said wheel brakes. The valve is incorporated within the hollow piston rond and communicates the two cylinder chambers during normal braking operation. Thus, during normal braking, fluid passes through the valve and therefore the piston remains in its initial position.

When wheel locking occurs, a control pressure is introduced from an auxiliary pressure source into another cylinder chamber, so that the piston moves, so that the valve is closed for the first time and the volume of the cylinder chamber communicating with the wheel brake is reduced. increases, and the volume of the cylinder chamber communicating with the brake master cylinder decreases. Thus, while actuation of the brake pressure regulator is commanded by the brake master cylinder to the driver via the brake pedal, the brake pressure is reduced in the desired manner in the wheel brakes in order to prevent locking. Placing a valve in a hollow piston rond is cumbersome and, moreover, only a portion of the piston's sliding stroke is used to shut off the valve, so that the drop in brake pressure occurs with a time delay. It has the disadvantage of occurring.

As a result, the wheels are released from locking with a delay that is desired from the viewpoint of good maneuverability of the vehicle itself.

According to West German Patent Application No. 2049262,
Brake systems are known which are equipped with a stepped piston with a return spring, a pressure regulator with a first cylinder chamber, a second cylinder chamber and a brake line cut-off valve. This first cylinder chamber is connected to one wheel brake and to the brake line isolation valve. The second cylinder chamber is pressurized as required, thereby moving the stepped piston which mechanically closes the brake line isolation valve via a plunger. As with the brake system, changes in brake pressure are disadvantageously delayed by closing the brake line isolation valve.

[Means for solving problems]

A hydraulic brake system for a vehicle having the construction means according to claims 1 and 2 can be constructed inexpensively by separately manufacturable solenoid valves, and as a result of the arrangement of such solenoid valves, the locking effect is reduced. Or, when drive slip occurs, by the time the brake pressure is changed to eliminate locking or limit drive slip,
It has the advantage of being essentially time-consuming.

According to the means described in claim B, the brake pressure regulator for eliminating wheel locking and the brake pressure regulator for limiting drive slip are combined with each other in the vehicle brake system.

Advantageous refinements and improvements of the vehicle braking system mentioned in claims 1 and 2 are made possible by the other measures described in claims 4 onwards. The measures according to claim 4 represent an advantageous configuration in combination with a brake pressure regulator which provides both anti-locking (ABS) and drive slip limiting (ASR) of the wheels.

The features recited in claim B indicate advantageous embodiments of a brake pressure regulator specified for avoiding wheel locking. The features according to claim 7 have the advantage that the return spring can be mounted space-savingly and at the same time be protected against corrosion due to contact with the brake pressure medium.

〔Example〕

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

The hydraulic brake system 2 of the vehicle comprises a brake master cylinder 5 controllable via a pedal rod 4 by a brake pedal 3, at least one brake line 6, at least one wheel brake 7 and at least one wheel locking system. Brake pressure regulator 8 (ABS
) and/or a brake pressure regulator 9 (ASR) for limiting drive slip.

The brake master cylinder 5 is constructed in particular as a two-circuit tandem brake master cylinder and is equipped with a brake force amplifier 10. As the brake force amplifier 10, a known vacuum brake force amplifier, a hydraulic brake force amplifier, or an electric brake force amplifier can be used.

The brake pressure regulator 8 includes a cylinder arrangement having a first cylinder 11, a second cylinder 12, and a sixth cylinder 13, a first piston 14, a second piston 15,
It has a third piston 16, a fourth t-stone 17, a fifth piston 18, two electromagnetic control valves 19, 20, and a brake line cutoff valve 21. first cylinder 1
1 and the first piston 14 define a first cylinder chamber 22 . The second cylinder 12 is the first cylinder 1
2 which have a larger diameter than 1 and are mutually stepped.
A second cylinder chamber 23 is defined with two pistons 15,16. The sixth cylinder 13 is the second cylinder 12
It also has a small diameter. The fifth piston 18 is slidable within the sixth cylinder 18. The second cylinder 12 and the piston door 17.18 are connected to the piston 17.1
The sixth cylinder chamber 24, which constitutes an annular chamber, is defined by the 8-step difference. A return spring 25, which is designed as a compression spring, is installed in this annular chamber. T-stones 15 and 16 and 17 and 18 are directly connected to each other. Bis)yl4.

15 are connected using rods 26. Furthermore, the pistons 16,17 are connected using another rod 27. Cylinder 11 has an end wall 28. A serrated abutment portion 29 is formed on the t-stone 14 toward the end wall 28 . From this contact portion 29, V stones 14°15.16.17.18 are arranged in that order. The return spring 25 is supported on a wall 30 forming the transition from the cylinder 12 to the cylinder 13. Therefore,
This return spring 25 is.

Via the piston 17, the piston 16, 15° 14 is pressed in the direction of the end wall 28, so that the abutment 29
comes into contact with. Each piston 14, 15. 16.
1γ, 18, each seal ring 31.32, 33.34.
35 has been assigned. The cylinder 11 has a connecting hole 36 adjacent to the end wall 28 . The cylinder 12 has a connection 38 adjacent to the wall 37 forming the transition between the cylinders 11 and 12. Another connection 39 is located near the wall 30. The cylinder 11 has a relief hole 4° in the area of the rod 26. A further relief hole 41 is provided in the cylinder 12 in the area of the rod 27. This escape hole 4
0.41 makes the space between seals 31 and 32 or between seals 33 and 34 in cylinders 11 and 12 atmospheric pressure. This relief hole 40.41 also drains any leakage. The sixth relief hole 42 is located at the free end of the cylinder 13.

The connecting portion 39 is in direct communication with the brake master cylinder 5 via the conduit 43 and the brake conduit 6. The brake line cutoff valve 21 is incorporated into the brake line 6. A further line 44 exits from the connection 36 and connects to the brake line 6 at an intermediate point between the brake line isolation valve 21 and the wheel brake 7. The connection part 38 is connected to the control conduit 4
5.46 to the control valve 19. Furthermore,
This connection 38 is connected to the second control valve 20 via a control line 45 and a further control line 47 . The first control valve 19 is normally in the open position and communicates the connection 38 with the redaper 49 of the pressure source 50 via the pressure relief line 48 . The pressure source 50 has a pump 51, a one-way valve 52 is disposed on the discharge side of the pump 51, and a pressure valve 53 is disposed behind the one-way valve 52. Pressure line 54 connects pressure source 50 to normally closed control valve 20.
is familiar with A pressure source 50 may be provided especially for the brake pressure regulator 8 . However, it is also possible to use other pressure sources in the vehicle as pressure source 50, for example pressure sources that are originally provided for supplying a steering accessory or a horizontal control device. Pressure source 50 may be a pressure source for supplying hydraulic brake force amplifier 10 .

The vehicle brake system 2 operates as follows.

When the brake pedal 3 is depressed, a brake master cylinder piston (of which only one brake master cylinder piston 55 is shown in the drawing) is activated inside the brake master cylinder, possibly by a brake force amplifier. With the cooperation of 10 people, it can be moved. As a result, a brake pressure is generated in the brake master cylinder 5 which is propagated via the brake line 6 to the wheel brake 7 through the brake line isolation valve 21 in the open position. The brake pressure in the wheel brake 7 causes a braking action on the wheels, which are not shown.

When the brake pedal 3 is depressed with a small force and the wheels are rotating on a hard-to-slip road surface, wheel locking cannot occur. However, if the brake pedal 3 is depressed forcefully, for example on a wet or icy road surface, wheel locking occurs. This means that
Although not shown in the drawings, this is detected in a known manner by means of wheel rotation speed sensors which are self-explanatory based on the state of the art. In such a case, the brake line isolation valve 21 is switched to the isolation position. Moreover, at the same time control valve 19 is switched to its blocking position and control valve 20 is opened. control valve 2
Due to the opening at 0, the pressure medium of the pressure source 50 flows into the second cylinder chamber 23 through the line 47.45. This fluid pressure acts on the annular surface of piston 16, which is defined by the diameters of pistons 15 and 16. Due to this action,
All pistons are moved against the force of the return spring 25 and the force caused by the pressure of the brake master cylinder 5 acting on the piston 17, so that the abutment 29 is freed from the end wall. They are pulled apart and the first cylinder chamber 22 is expanded. Therefore, the pressure medium of the wheel brake 7 flows into the cylinder 11 and the brake pressure decreases. At the same time, the sixth cylinder chamber 24 contracts due to the movement of the V-stone 17 in the direction of the wall 30, so that the pressure medium is forced out of the sixth cylinder chamber and passes through the line 43 and the brake line 6. and is guided to the brake master cylinder 5. This pressure medium moves the piston 55 of the brake master cylinder in the direction of the brake pedal 3, so that
The actuation of the brake pressure regulator 8 can be felt at the brake pedal 3.

As soon as the locking is eliminated as a result of the pressure drop and the rotational speed of the wheels has thereby increased sufficiently, the control valve 20 is closed and the control valve 19 is opened. As a result, the second cylinder chamber 23 is released from the pressure of the pressure source 50,
The pistons 14 and 17 are then driven by the force of the return spring 25 and the piston 1 which is limited by the diameters of the pistons 17 and 18.
The force acting on the annular surface of 7 causes it to move in the direction of its initial position. The pressure medium in the first cylinder chamber 22 is thereby forced back into the brake line 6 and into the wheel brakes 7. The brake pressure in the wheel brakes therefore increases, whereby the vehicle equipped with wheel brakes 7 is decelerated again. At the same time, the sixth cylinder chamber 24 expands,
Then, pressure medium is sucked in from the brake master cylinder 5. This can be felt again at the brake pedal 3. The diameter of piston 18 is selected such that the pressure receiving area of piston 17 defined between the diameter of piston 18 and the diameter of piston 17 is essentially the same as the area defined by the diameter of piston 14. has been done. Thereby,.

During normal brake operation, the t-stone 14 and piston 17
, 18 is essentially pressure balanced in the axial direction. It is therefore sufficient for the return spring 25 to be weak enough to move the piston 14, 17 to its initial position when the brake pedal 3 is released and the brake line isolation valve 21 is opened.

Brake pressure regulator 9 (AS
R) comprises a cylinder 56, a piston 57, two seal rings 58, 59, a return spring 60, two control valves 61, 62 and the brake pressure regulator 8 (ABS
) and the brake line cutoff valve 21 that operates in conjunction with the brake line cutoff valve 21. The cylinder 56 has an end wall 63 with a connection 64 and a variable volume cylinder chamber 73 extending from the connection to the piston 57 . End wall 63 and piston 51
A return spring 60 is incorporated between 0 and 0. This return spring 60 normally presses the piston 57 to the initial position. In this initial position, the abutment 65 formed on the piston 57 adjoins the closed end wall 66 of the cylinder 56 . Cylinder 56 has another connection 67 near end wall 66 . This connection 67 is connected to the control valve 61 via lines 68,69. This control valve 61 is connected to a relief pipe 48 that opens into the reservoir 49, similar to the example of the brake pressure regulator 8. Connection 67 is connected to control valve 62 via line 68 and line 70 . A pressure line 54 leading from the pressure source 50 communicates with this control valve 62 .

This pressure source 50 is configured similarly to the pressure source of the brake pressure regulator 8. For example, such a pressure source 50 can supply both the brake pressure regulator 8 and the brake pressure regulator 9 described here.

The control valve 61 is open under normal conditions;
2 is closed under normal conditions. The connection 64 of the brake pressure regulator 9 is connected via a line 71 at a point intermediate the brake line isolation valve 21 and the wheel brake 7.
It is connected to the brake line 6.

The brake pressure regulator 9, which limits drive slip, operates as follows.

When, with the brake pedal 3 released, the drive engine (not shown) of the vehicle drives the drive wheels associated with the brake 7, in particular, the drive torque does not cause an undesirably excessive drive slip. Brake line isolation valve 21 will remain in its open position, and control valve 61 will also remain in its open position. At this time, the control valve 62 remains closed. When an undesirable excessive drive slip occurs due to an increase in the drive torque of the drive engine or the drive wheels move from a non-slip road surface area to a slippery road surface area, the valve 21
and 61 are switched to their shutoff position and valve 62 is opened.

An unacceptably excessive drive slip is detected using a wheel speed sensor, which is already used in conjunction with a brake pressure regulator 8 that is specifically designed to prevent wheel locking. When the control valve 62 opens, the pressure medium flows through the line 70.68 and the connection 67 into the cylinder 5.
6. Thereby, the end wall 66 of the piston 57
A pressure is generated at the end facing the piston 57, which moves the piston 57 against the action of the spring 600. As a result, the piston 57 forces pressure medium out of the cylinder chamber 73 of the cylinder 56.

At this time, the pressure medium is transferred to the closed brake line isolation valve 21.
is isolated from the brake master cylinder 5 by the brake master cylinder 5 and is therefore introduced only into the wheel brakes. A braking pressure is therefore generated in the wheel brake 7, which causes a good reduction of the drive slip. If there is no brake pressure regulator 8 for eliminating wheel locking in the brake system of the vehicle, adding a brake line cutoff valve 21 to the above-described configuration of the brake pressure regulator will be effective as a system. However, if the brake pressure regulator 9 for reducing drive slip is combined with the brake pressure regulator 8 as shown in the brake system of the vehicle, the cut-off position is set to prevent drive slip. an additional valve 7 which is switched over and prevents the pressure medium of the brake pressure regulator 9 from flowing into the brake pressure regulator 8;
2 is required.

This valve 72 is in this case connected to the already mentioned line 44.
built into it. The valve 72 therefore has the advantage of making all the medium forced out of the cylinder 56 available for building up the brake pressure in the wheel brake 7 when preventing drive slip. Otherwise, the cylinder 56 would have to be constructed with a large volume, and the entire fruiting device would be heavy and expensive, and could even lead to more energy consumption. The brake line cutoff valve 21 and the valve 72 are, for example, a 4/6 valve (4/6 valve).
(6-position valve).

As already mentioned, the brake system of the vehicle is equipped, as shown, with a brake pressure regulator 8 to prevent wheel locking and also with a brake pressure regulator 9 to reduce drive slip to an advantageous magnitude. be able to. On the other hand, if the cost of a vehicle equipped with these pressure regulators is to be reduced, it is also possible to equip the vehicle with only one of the two pressure regulators. However, in both said cases of automatically controlling the brake pressure in the wheel brakes 7, the brake line 6 will be closed on the side of the brake master cylinder 5. The brake line isolation valve 21 used here can be switched from the basic position to the second position with essentially the same speed as the valves 19.20 to 61.62, so that The changes in brake pressure required to eliminate locking or limit drive slip begin very quickly.

Vehicles equipped in this way can therefore be better controlled.

The invention has so far been explained in detail in connection with only one wheel brake 7. It is clear that it is possible to assign one brake pressure regulator 8 and/or 9 to each wheel brake of the vehicle. In any case, it is advantageous to assign one brake pressure regulator to each front wheel brake. To keep costs low, for example, one brake pressure regulator 8 can be assigned to several wheel brakes of the rear axle. If the vehicle is equipped to limit drive slip, one brake pressure regulator 9 is provided for each drive wheel. However, it is also possible to provide only one brake pressure regulator 9 and a valve arrangement for transmitting the brake pressure generated by this brake pressure regulator 9 only to the wheel brakes of the wheels on which excessive drive slip occurs. It is.

[Brief explanation of the drawing]

The drawings are schematic illustrations of embodiments of the invention.

Claims (1)

[Scope of Claims] 1. A brake master cylinder and at least one wheel brake, and a brake line connected to the master cylinder is cut off by moving a piston and using a brake line cutoff valve. at least one cylinder chamber connected between the wheel brake and the brake master cylinder for automatically changing the brake pressure by moving a pressure medium between the one cylinder chamber defined by the piston of the cylinder and the wheel brake; In a vehicle hydraulic brake system of the type with two brake pressure regulators, the brake line isolation valve (21) is independent of the movement of the piston (14) of the brake pressure regulator (8). Hydraulic brake system for a vehicle, characterized in that it is constructed as an electromagnetically controllable valve, and that the brake pressure regulator (8) is constructed as an anti-locking device. 2. comprising a brake master cylinder and at least one wheel brake, and limited by the piston of the cylinder by movement of the piston and interruption of the brake line communicating with said master cylinder using a brake line isolation valve; at least one brake pressure regulator connected between the wheel brake and the brake master cylinder for automatically changing the brake pressure by moving pressure medium between the wheel brake and the wheel brake; A hydraulic brake system for a vehicle of the type comprising: the brake line isolation valve (21) being electromagnetically controllable independently of the movement of the piston (57) of the brake pressure regulator (9); configured as a valve, said brake pressure regulator (9);
has a cylinder (56) configured as a brake pressure regulator for limiting drive slip and slidably carrying the piston (57);
A cylinder chamber (7) that is freely retractable by the piston (57)
3) is connected to the brake line (6) intermediately between the brake line isolation valve (21) and the associated wheel brake (7). . 3. An additional brake pressure regulator (8) configured as a brake pressure regulator to prevent locking,
Said brake line (6
3. The hydraulic brake system for a vehicle according to claim 2, wherein the hydraulic brake system is connected to a hydraulic brake system. 4. Hydraulic brake system for a vehicle according to claim 3, characterized in that the brake line isolation valve (21) and the additional valve (72) are constructed as one multi-way valve. 5. The brake pressure regulator (8) has another cylinder chamber (24), which always communicates with the brake master cylinder (5) and which is connected to the first cylinder chamber (24). Claim 1, characterized in that when the volume of 22) increases, the volume of the other cylinder chamber decreases.
Hydraulic brake system for the vehicle described. 6. The cylinder chamber (24), which is always in communication with the brake master cylinder (5), is a stepped piston-type integrated cylinder chamber (24).
being limited by two pistons (17, 18), the hydraulically effective annular surface of said pistons (17) having a relatively large diameter prevents said wheel brake (7) from locking. Claim 5 characterized in that the piston (14) has an area of essentially the same magnitude as the area defined by the diameter of the piston (14) subjected to a braking pressure of
Hydraulic brake system for the vehicle described. 7. The hydraulic brake system for a vehicle according to claim 5 or 6, characterized in that a return spring (25) is incorporated in the cylinder chamber (24) that is always in communication with the brake master cylinder (5). .