DE4014052A1 - Electronic pressure regulator for vehicular hydraulic braking system - establishes corrective connection between brake fluid reservoirs serving master cylinder and two-pump fluid pressure modulator - Google Patents

Abstract

The master cylinder (1) and a pressure modulator with wheel brake cylinder inlet and outlet valves (12-14, 18-20) are supplied from separate brake fluid reservoirs (2, 3) at different levels (24). - These valves and a motor (6) driving two pumps (4, 5) are switched by an electronic regulator in response to wheel speed detectors and sensors of fluid levels (7, 8) and master cylinder piston position (9). Fluid is driven reciprocally between the reservoirs (2, 3) to counteract any deficit.

Description

The invention relates to a brake pressure control device, especially for motor vehicles with an anti-lock control system (ABS) and / or a traction control system tem (ASR) with a fluid, especially hydrau mix, pressure fluid works, consisting of a main cylinder, a pressure modulator for changing the hydraulic pressure in the wheel cylinders of the wheel brakes during a brake pressure control mode, the pressure module gate among other things inlet and outlet valves for the Radzy includes at least one motor-driven pump to generate a fluid, especially hydraulic pressure, an electronic controller among others for controlling the valves of the pressure modulator, one Fluid reservoir for the master cylinder and a pressure medium reservoir for the pressure modulator.

The subject of this genus belongs to the genus Invention to the anti-lock braking systems that can optionally have a traction control system.

By the German patent application 36 35 054 is one such anti-lock brake system with traction regulation consisting essentially of a pedal approved, preferably auxiliary brake pressure with a master cylinder,  the wheel brakes on the main brake lines are closed, from hydraulic auxiliary pressure pumps, as well as from wheel sensors and electronic circuits to determine the wheel turning behavior and to generate of electrical brake pressure control signals with which inserted into the pressure medium line for slip control Electromagnetically actuated pressure fluid inlet valves and exhaust valves are controllable, the Bremslei intakes via the inflow lines with the motorized drives connected pumps, their suction connections connected to the trailing tank via a suction line have become known.

This German laid-open specification proposes gene that in at least one of the two inflow lines a valve is switched on, for the purpose of Drive slip control pressure medium in a brake circuit is conveyable, the pump connecting the valve end section of the inflow line via a short circuit Line in one of the main brake line is connected and a pressure relief valve is inserted into the short-circuit line is switched on, the feeding of pressure medium the short-circuit line into the main brake line Exceeding a minimum pressure allows a flow of the pressure medium in the opposite direction, however excludes and with a pressure medium storage with this Short-circuit line is connected, in which the pump up promotes to reach the minimum pressure.  

Suction lines between the pressure medium container of the Master cylinder and the suction side of the pumps as they presented in the aforementioned German published application are fundamentally problematic. They are in particular their susceptible to failure. The laying of such Sauglei is complicated and costly.

The invention is based on the following objects: The disadvantages of the prior art described are intended be avoided. It is said to be a brake pressure control device be created without suction lines between the Master cylinder fluid reservoir and pumps suction side gets along. The susceptibility to faults should be reduced and the safety of the system should be increased. The system should be vented in a simple manner can. The manufacturing costs are to be reduced. The operational capability of the brake pressure control device should become more versatile.

If there are two pressure fluid reservoirs, namely a master cylinder container and a modulator Container is designed to be a simple, uncomplicated hydraulic Connection between these two containers may be possible.

The tasks set according to the invention solved that the valves of the pressure modulator designed so and are arranged that a pressure medium connection between the pressure medium reservoir of the main cylinder ders (master cylinder container) and the pressure medium rats tank of the pressure modulator (modulator tank) will be produced.  

It can be provided that pressure medium from the Modulator tank by at least one pump in the Master cylinder container is promoted.

It is also proposed that pressure medium from the Master cylinder container due to gravity in the modules door container is promoted.

Alternatively or additionally, the pressure medium from the Master cylinder container by operating the master cylinder be conveyed into the modulator tank.

In a further embodiment of the invention, it is proposed conditions that the master cylinder container and the modulator container ter each with a sensing device for the height of the Pressure medium levels (level sensors) are provided, the actual values as measuring elements as input signals for make the controller available.

It can be provided that at least one fill level sensor is designed as a warning display device, those when the value falls below or exceeds a permissible level triggers a warning signal.

In a further preferred embodiment of the Invention it is proposed that an overflow line is provided which in relation to the modulator tank higher master cylinder container with the modulator container connects.

In a further embodiment of this proposal is proposed see that the overflow line above the pressure medium levels  ends in the master cylinder tank and modulator tank, so that self-ventilation of the overflow line is achieved becomes.

It is also proposed that the flow behind at least one valve is arranged in the master cylinder, the main cycle in traction control mode (ASR mode) separates linder from the pressure modulator (ASR check valve) that the ASR shut-off valve is bridged by a bypass line is that in the bypass line a pressure relief valve, the opens to the tandem master cylinder, (bypass overpressure valve) is provided.

This makes it possible for the pump to over in the ASR mode a bypass pressure relief valve with closed ASR shut-off valve til pressure medium from the modulator tank into the main cylinder container supports.

In particular, it is proposed that the controller pedal travel sensor signals and level sensor signals for one Process output signal for the drive motor of the pump Tet that the pump with the output signal Druckmit telvolumes from the modulator tank into the main cylinder the container conveys.

It is also provided that the regulator Füllstandsge processed over signals to an output signal, the one Balance of those in the master cylinder tank and modulator tank pressure medium quantities and thus a note represents the degree of wear of the brake pads.  

The following advantages are achieved by the invention: The tasks are solved. The fiction moderate brake pressure control device comes without suction lines between master cylinder pressure medium reservoir and Pump suction side off. The susceptibility to faults is reduced. The safety of the system is improved. In terms of on the usability of the brake pressure control device a high degree of flexibility is achieved. Between the master cylinder tank and the modulator tank by skillful control of the solenoid valves simple, uncomplicated hydraulic connection fen.

Further details of the invention, the task and the advantages achieved are the following description two embodiments of the invention.

These exemplary embodiments are based on two figures explained.

Figs. 1 and 2 show hydraulic circuit diagrams of the two embodiments.

In the following description of the execution games of the invention is based on a prior art assumed, for example, in the form of the above cited published publication 36 35 056. The Description and the figures of this document can be used Explanation of the starting point for the following described embodiments of the invention to be pulled.  

The brake pressure control device according to FIG. 1 has a master cylinder 1 and a pressure modulator as essential components.

The pressure modulator consists of several electromagnetic Actuable normally open valves (SO valves) and Normally closed valves (SG valves), as well as off Check and pressure relief valves, which are further down in the individual still to be described.

The pressure medium reservoir 2 belongs to the master cylinder. The pressure medium reservoir 3 is assigned to the pressure modulator. 4 , 5 show two pumps which are driven by the motor 6 .

With 7 , 8 level sensors are designated that sense the pressure medium level of the master cylinder container or modulator container.

With 9 a displacement sensor is designated, which senses the position of the brake pedal, the servo piston, for example a vacuum brake booster, or the push rod piston of the tandem master cylinder.

Not shown is an electronic controller which records the actual values of wheel sensors (not shown) and the fill level sensor and the displacement sensor 9 at its input. The controller, which can include a digitally operating computer, processes these signals (actual values) into output signals. The motor of the pumps and the SO or SG valves of the pressure modulator are controlled or switched with the output signals.

In normal braking mode, pressure medium is conveyed to the wheel cylinders through the open SO valves 10 , 11 (ASR shut-off valves) and the open intake valves (SO valves) 12 , 13 , 14 when the master cylinder is actuated. The leads to the wheel cylinders are designated 15 , 16 , 17 . During the normal braking mode, the exhaust valves 18 , 19 , 20 , which are designed as SG valves, are closed.

In ABS mode, the intake and exhaust valves are the are each assigned to a wheel cylinder by output signal nals of the controller switched so that for this mode necessary pressure reduction phases, pressure constant phases and pressure recovery phases are generated, see here the above-mentioned prior art.

In detail, the following happens in ABS mode: The motor 6 is started by an output signal from the controller and the pumps 4 , 5 convey pressure medium from the modulator tank 3 into the pressure modulator system.

The wheel cylinder line 17 will now be used to illustrate how the individual phases are generated: during the pressure reduction phase, the inlet valve 14 is closed and the outlet valve 18 is opened, pressure medium can thus reach the modulator tank 3 via the line 21 .

During the pressure maintenance phase, inlet valve 14 and outlet valve 18 are closed. During the pressure recovery phase, the inlet valve is opened while the outlet valve is closed.

The inlet valves and the outlet valves, which are assigned to the wheel cylinder lines 16 and 15 , operate in a corresponding manner.

With 22 , 23 pressure relief valves are designated that open to the modulator tank 3 and ensure that an upper pressure limit in the modulator system is not exceeded.

In the ASR mode, the ASR check valves 10 , 11 are closed. This will separate the pressure modulator from the master cylinder.

The pressure rise phase in ASR mode is, as above in Described in connection with the ABS mode. The same applies if this is featured in the control algorithm should be seen for the constant pressure phase and Depressurization phase during ASR mode.

If the level sensor 7 gives actual values as input signals to the controller, which indicate a pressure medium deficiency in the main cylinder 2 , are outside of the control mode or during a control mode, if the control algorithm permits, by the pumps 4 , 5 pressure medium by the Tandem master cylinder in the master cylinder container 2 promoted. This requires special switching of certain valves in the modulator system. This circuit is described below.

If the actual values of the level sensor 8 indicate that a pressure medium deficit has occurred in the modulator tank, then the valves of the modulator are switched so that pressure medium can flow from the main cylinder into the modulator tank by gravity. The prerequisite is that the master cylinder container is arranged higher than the modulator container in relation to the modulator container 3 . With the route 24 , a height difference between the pressure medium level of the main cylinder derbehälters and that of the modulator tank is designated.

Furthermore, according to the embodiment of FIG. 1, it is possible to promote pressure medium from the master cylinder container into the modulator container by actuating the master cylinder if there is a pressure medium deficit in the modulator container.

The connections between the modulator tank and the Master cylinder container while refilling the master cylinder container by the pumps comes about as follows:

The inlet valves 14 , 13 , 12 are closed, the outlet valves 18 , 19 , 20 are closed. The pumps convey from the modulator tank via lines 25 , 26 via the ASR blocking valves 10 , 11 in the open position and via the open central valves in the master cylinder pressure medium into the master cylinder tank 2 .

If pressure medium is to be conveyed from the master cylinder tank by gravity into the modulator tank, the following situation exists: The central valves of the tandem master cylinder are open, the shut-off valves for the ASR mode are also in the open position, the inlet valves are open and the outlet valves are open open. Pressure medium can thus flow via the lines 25 , 27 , 28 , 26 , 21 in the Modulatorbe container.

As mentioned, pressure medium can also be conveyed from the master cylinder container into the modular gate container by actuating the master cylinder. The working spaces of the master cylinder are filled with pressure medium from the reservoir of the master cylinder. When the main cylinder is actuated, pressure medium is pressed into the modulator chamber via the open ASR shut-off valves 10 , 11 , the open inlet valves and the open outlet valves.

Advantageously, the level sensors can additionally Lich formed as warning devices that trigger a warning signal.

The embodiment according to FIG. 2 is a variant of the embodiment according to FIG. 1. The pressure module arrangement and the master cylinder arrangement are essentially configured in FIG. 2 as shown in FIG. 1.

The difference between the exemplary embodiments according to FIGS. 1 and 2 is that an overflow line 38 is provided in FIG. 2, which connects the master cylinder container to the modulator container. The direction of flow of the pressure medium in the overflow line 39 is indicated by the arrow 38 .

The master cylinder container is locally seen higher than the modulator container. When the pressure medium level in the master cylinder container has reached a certain level, pressure medium flows via the overflow line from the master cylinder container into the modulator container. The orifices 30 , 31 of the overflow line in the main tank, or in the modulator tank, are arranged above the level of the pressure medium. The overflow line bleeds itself.

If, for example, the level in the master cylinder container rises so far that pressure medium runs through the overflow line into the modulator container, then air bubbles in the overflow line at the mouth 31 in the modulator container can escape into the atmosphere.

The exemplary embodiment according to FIG. 2 has the special feature compared to FIG. 1 that the ASR check valves 10 , 11 are bridged by bypass lines 32 , 33 . The pressure relief valves 34 , 35 , which open toward the tandem master cylinder, are arranged in the bypass lines.

In ASR mode, the pumps 4 , 5 via the lines 25 , 26 and 32 , 33 can open the pressure relief valves 34 , 35 when a certain pressure is reached. Pressure medium then flows via lines 36 , 37 through the open central valves of the tandem master cylinder into master cylinder container 2 .

Basically, the actual values of the wheel sensors apply nale, the level sensor signals and the pedal travel sensor signals entered at the input of the controller processed into output signals at the output of the controller will. These output signals are used to control the various SO and SG valves and the drive motor for the pumps. Refilling the master cylinder tank or the modulator tank can be during or outside a control mode take place. Find the refill during a control mode instead, then it is provided that the Filling is carried out without disturbing the control mode.

For example, the volumes delivered from the modulator tank to the master cylinder tank are dependent on an output signal from the controller for the drive motor of the pump. These output signals are calculated by the controller, among other things, based on the level sensor signals. The signal from the displacement sensor 9 provides information about the situation in which the master cylinder and the central valves of the master cylinder are. The central valves must be open to convey the pressure medium through the pumps from the modulator container 3 into the master cylinder container 2 .

The level sensor signals can continue through the Controller, which is preferably designed as a computer, to a balance sheet  that in the master cylinder tank and modulator tank existing pressure medium quantities are processed. These Balance provides information about the degree of wear the brake pads.

List of items

1 master cylinder
2 containers
3 containers
4 pump
5 pump
6 engine
7 level sensor
8 level sensors
9 displacement sensor, displacement sensor
10 SO valve, ASR shut-off valve
11 SO valve, ASR shut-off valve
12 SO valve
13 SO valve
14 SO valve
15 supply line
16 supply line
17 supply line
18 SG valve
19 SG valve
20 SG valve
21 line
22 pressure relief valve
23 pressure relief valve
24 height difference
25 line
26 line
27 line
28 line
30 mouth
31 mouth
32 bypass line
33 Bypass line
34 pressure relief valve
35 pressure relief valve
36 line
37 line
38 arrow
39 Management

Claims (12)

1. Brake pressure control device, in particular for motor vehicles with an anti-lock control system (ABS) and / or a traction control system (ASR), which works with a fluid, in particular hydraulic, pressure medium, consisting of a master cylinder, a pressure modulator for changing the hydraulic pressure in the Wheel cylinders of the wheel brakes during a brake pressure control mode, the pressure modulator including, among other things, inlet and outlet valves for the wheel cylinders, at least one motor-driven pump for generating a fluidic, in particular hydraulic pressure, an electronic controller for controlling the valves of the pressure modulator, among others Pressure medium supply container for the master cylinder and a Druckmit telvorrats container for the pressure modulator, characterized in that the valves of the pressure modulator are designed and arranged so that a pressure medium connection between the pressure medium supply container ( 2 ) of the master cylinder ( 1 ) (master cylinder container) and the pressure medium reservoir container ( 3 ) of the pressure modulator (modulator container) is produced. 2. A method for using a Bremsdruckregelvorrich device according to claim 1, characterized in that pressure medium from the modulator tank ( 3 ) by at least one pump in the master cylinder container ( 2 ) is conveyed. 3. A method for applying a Bremsdruckregelvorrich device according to claim 1, characterized in that pressure medium from the master cylinder container ( 2 ) is promoted by the heavy force in the modulator container ( 3 ). 4. A method for using a Bremsdruckregelvorrich device according to claim 1, characterized in that pressure medium from the master cylinder container ( 2 ) by the actuation of the master cylinder ( 1 ) in the modulator container ( 3 ) is promoted. 5. The device according to one or more of the preceding gene claims, characterized in that the main cylinder container ( 2 ) and the modulator container ( 3 ) are each provided with a sensing device for the level of Druckmit tel levels (level sensor) ( 7 , 8 ) which, as measuring elements, provide actual values as input signals for the controller. 6. Device according to one or more of the preceding gene claims, characterized in that at least a level sensor is designed as a warning display device is that when the value falls below or exceeds a permissible level triggers a warning signal.   7. Brake pressure control device, in particular for motor vehicles with an anti-lock control system (ABS) and / or a traction control system (ASR), which works with a fluid, in particular hydraulic, pressure medium, consisting of a master cylinder, a pressure modulator for changing the hydraulic pressure in the Wheel cylinders of the wheel brakes during a brake pressure control mode, the pressure modulator including, among other things, inlet and outlet valves for the wheel cylinders, at least one motor-driven pump for generating a fluidic, in particular hydraulic pressure, an electronic controller for controlling the valves of the pressure modulator, among others Pressure medium supply container for the master cylinder and a pressure medium supply container for the pressure modulator, in particular according to one or more of the preceding claims, characterized in that an overflow line device ( 39 ) is provided, which the in relation to the mod Lator container ( 3 ) higher master cylinder container ( 2 ) connects to the modulator container ( 3 ). 8. The device according to claim 7, characterized in that the overflow line ( 39 ) above the pressure medium level in the master cylinder container ( 2 ) and modulator container ( 3 ) ends, so that self-ventilation of the overflow line device ( 39 ) is achieved. 9. The device according to one or more of the preceding gene claims, characterized in that at least one valve is arranged in terms of flow behind the master cylinder, which separates the master cylinder from the pressure modulator in the traction control mode (ASR mode) (ASR check valve) ( 10 , 11 ) that the ASR shut-off valve is bridged by a bypass line ( 33 , 32 ), that in the bypass line a pressure relief valve ( 34 , 35 ) that opens towards the tandem master cylinder ( 1 ) (bypass pressure relief valve) is provided. 10. A method for using a Bremsdruckregelvorrich device according to one or more of the preceding Ansprü surface, characterized in that in the ASR mode, the pump ( 4 , 5 ) via a bypass pressure relief valve ( 34 , 35 ) with the ASR shut-off valve pressure medium from the Modular door container ( 3 ) through the master cylinder ( 1 ) in the master cylinder container ( 2 ) promotes. 11. A method for using a Bremsdruckregelvorrich device according to one or more of the preceding Ansprü surface, characterized in that the controller Pedalwegsen sensor signals and level sensor signals to an output signal for the drive motor ( 6 ) of the pump ( 4 , 5 ) processed that the pump due to the output signal pressure medium volumes from the modulator tank ( 3 ) in the main cylinder tank ( 2 ) promotes. 12. A method for applying a Bremsdruckregelvorrich device according to one or more of the preceding claims, characterized in that the controller processes level sensor signals to an output signal which is a balance of the master cylinder container ( 2 ) and modulator gate container ( 3 ) located pressure medium quantities and thus one Indicates the degree of wear of the brake pads.