JPH0717192B2 - Method for using a pressure regulator of a vehicle braking system and vehicle braking system - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention has at least one adjustable setpoint generator and at least two pressure regulating valves, the pressure regulating valves being at least two separate from each other. , For example, to create a pressure in a wheel brake cylinder at least approximately at the same time, to which a pressure sensor is assigned, which pressure sensor transmits an electrical value related to the pressure acting on it. The present invention relates to a vehicle brake device.

2. Description of the Related Art A vehicle braking device known from GB-PS1328127 is one pump, at least one pressure accumulator, a wheel brake cylinder, a brake pressure control valve arranged between the two, and the brake. A brake pressure sensor connected to a pressure control valve for measuring a brake pressure acting in a wheel brake cylinder, an electric brake pressure selector adjustable by a driving brake pedal, the brake pressure selector and a brake pressure sensor And an electronic regulator connected to the. During operation control, the brake pressure is selected depending on the operation brake pedal. The regulator compares the signal sent from the brake pressure selector with the display signal from the brake pressure sensor and controls the brake pressure control valve to accurately bring the brake pressure in the wheel brake cylinders to the selected brake pressure. Match. Especially in order to minimize steering operations during sudden braking, the braking pressures on the left and right wheels of the axle must be the same. The most important prerequisite for this is that the left and right brake pressure sensors do not show a large display error when loaded with equal pressure. However, the manufacture and adjustment of such precision pressure sensors is very expensive. Also, selecting the brake pressure sensors in pairs is too expensive, and likewise, replacing such pressure sensors in pairs is also too expensive.

[Problem to be Solved by the Invention] The problem to be solved by the present invention is to adjust the pressure in the vehicle braking device of the type described at the beginning even when the display signals of the pressure sensors arranged on the left and right have a deviation due to the manufacturing error and the adjustment error of the pressure sensor. A vehicle braking device and a vehicle brake system are provided which enable the device to create equal pressure in the left and right wheel brake cylinders.

[Means for Solving the Problem] The above-mentioned problem is, in terms of method, in a vehicle brake system of the type described at the beginning, at least the same magnitude of pressure is simultaneously supplied to all the pressure sensors before the pressure regulator operates normally. Then, an electrical reference value is made to correspond to each pressure, a correction value is obtained from this reference value and the value sent from the pressure sensor, and this correction value is used during normal operation of the pressure regulator. To correct the value displayed by the pressure sensor and then send it to the pressure regulator as the actual value.
By using such a method, even if both pressure sensors do not output the same display signal when the same pressure is applied to the left and right pressure sensors, the pressure adjuster can be used according to the manufacturing error and the adjustment error of the pressure sensor. It is possible with simple means to create an equal pressure in the left and right wheel brake cylinders.

In view of the device, in the vehicle braking device of the type described at the beginning, the control / correction device is assigned to the pressure regulator, and the control / correction device is the same for the purpose of effecting via the pressure adjustment valve. At least one pressure of a magnitude is supplied to all the pressure sensors at the same time, and the correction value is detected from the difference between the electrical value sent from the pressure sensor and at least one corresponding reference value. It has been solved by the fact that the value delivered by the pressure sensor during normal operation of the pressure regulator is corrected in accordance with the correction value and is supplied to the pressure regulator as an actual value. In such a braking device, manufacturing errors and / or
Even if you use a cheap brake pressure sensor that has a large error during adjustment, the controller displays the target value and the actual value as accurately as the display value sent from the precise and expensive brake pressure sensor. Will be given for comparison.

[Embodiment] According to the features of claim 2, a simple and cheap method of loading the pressure sensor to obtain the correction value can be obtained. This equalizes the small braking forces on the left and right sides of the vehicle, making it easier to control on frozen or snowy road surfaces. The feature of claim 3 makes it possible to accurately match the brake pressures on both sides of the vehicle even when the brake pressure is high. This brings about the advantage that the steering wheel hardly flutters when fully braked and that little steering force is required to maintain the desired direction of travel of the vehicle. Claim 4 describes a method of providing the pressure required for obtaining the correction value in the simplest form. Claim 5 describes a method for obtaining a correction value without using a corrected pressure sensor.

The features as claimed in claim 8 enable an inexpensive construction of the regulator which operates digitally and controls the brake pressure control valve.

[Embodiment] The vehicle brake device 2 includes at least one wheel brake cylinder 4 assigned to the right wheel 3, and at least one wheel brake cylinder 6 assigned to the left wheel 5.
Brake pressure regulating valves 7 or 8 arranged one by one on the left and right, brake pressure conduits 9,10, pressure conduits 11,12,13, at least one pressure accumulator 14, and one left and right measuring connection The conduit 15 or 16, the pressure sensor 17,18, the measured value amplifier 19,20, the control and correction device 21,22, at least a one-way electrical target value generator 23, and the brake pedal 24, And a pressure regulator 25. The right wheel brake cylinder 4 and the left wheel brake cylinder 6 are connected to a right or left brake pressure adjusting valve 7 or 8 via a brake pressure conduit 9 or 10, respectively. The brake pressure adjusting valve 7 or 8 is a pressure accumulator via pressure conduits 11, 12, and 13.
The functions connected to the switch 14 are, for example, electromagnetically controllable three-port three-position valves and are assigned to the switching positions, that is, "shutdown and brake pressure maintenance", "brake pressure increase", and "brake pressure increase". Descending ". The pressure accumulator 14 is filled with a pump (not shown) in a manner known per se. In this case, the pump may either pump air or the like or a hydraulic pressure medium. Brake pressure adjustment valve 7,8
The construction type of the wheel brake cylinders 4 and 6 is adapted to the pressure medium used.

The measuring connection conduits 15, 16 are connected to the brake pressure conduits 9, 10 and the pressure sensors 17, 18 are connected to the wheel brake cylinders 4, 6.

The pressure sensors 17, 18 are configured in any way, for example as pressure measuring boxes, the diaphragm (not shown) of the pressure measuring boxes holding a strain gauge (also not shown) made of semiconductor material. .
A plurality of strain gauges may be assigned to one diaphragm and may be combined into a so-called bridge circuit. The measurement value amplifiers 19 and 20 are, first of all, the pressure sensor 1
It serves to amplify the measurement signal from 7, 18 and at least send it towards the pressure regulator 25 without interruption. For this purpose, the measurement amplifier is integrated directly with the pressure sensor, for example. The measurement value amplifiers 19, 20 are also advantageously used to supply the operating current to the pressure sensors 17, 18. Furthermore, the measurement value amplifier is an electrical lead 2 leading to the control and correction device 21, 22.
It can also be used to give 6,27 a wire monitoring level. A current or voltage delivered from the pressure sensor is applied to each of the conductor monitoring levels. As a result, the conductor
26,27 breaks can be detected. The signal (quantity) sent from the measured value amplifier 19, 20 or the control and correction device 21, 22 is a voltage or a current. The function of the control and correction devices 21, 22 is that the measured values sent via the conductors 26, 27 are subject to the precondition that the pressures created in the pressure sensor are of exactly the same magnitude at the same time. Is to modify the measurements so that are the same. This correction is performed, for example, when the vehicle is stationary by being stopped by the parking brake and using the control / correction devices 21 and 22 to adjust the brake pressure adjustment valves.
It is performed by switching 7, 8 to the same control position over a predetermined time period. In the "brake pressure drop" control position,
The brake pressure adjusting valves 7 and 8 connect the pressure sensors 17 and 18 to the ambient atmospheric pressure. As a result, the correction values are obtained by the control and correction devices 21 and 22. When the brake pressure adjusting valves 7 and 8 are controlled to the “brake pressure increase” control position, the pressure in the pressure sensors 17 and 18 is increased to the pressure in the pressure accumulator 14.

In the above-mentioned load condition, both pressure sensors 17, 18 follow the ideal characteristic curve as indicated by the symbol K in FIG. 2 via the measured value amplifiers 19, 20 and the control and correction devices 21, 22. Such a signal must be sent to the pressure controller 25.
The characteristic curve K is, for example, a straight line. For example, the voltage p1 corresponds to the point p1 and the voltage p2 corresponds to the point p2. The current amounts I1, I2 or the frequency may be taken out instead of the voltage. However,
The electrical signal sent to the inlets of the control / correction devices 21 and 22 is a characteristic deviated from the characteristic curve K on the basis of manufacturing error and adjustment error in the pressure sensors 17 and 18 and the measured value amplifiers 19 and 20. Above the curves K17 and K18. Control and correction device 2
1,22 are, for example, the correction values AW17 and AW'17 and AW18 for the pressures p1 and p2 between the time periods when the brake pressure adjusting valves 7 and 8 are in the "brake pressure increasing" position and the "brake pressure decreasing" position.
Detect AW'18. Since the control / correction device is configured as means for automatically controlling and adjusting, the correction necessary for moving the characteristic curve to the characteristic curve K is automatically performed when the vehicle starts to operate. For this purpose it is possible to form the means as a so-called equalization network. However, it is also possible to configure the means in such a way that the correction values for the further pressure stages located between the pressure stages p1 and p2 can be determined by measuring or interpolating.

Another possibility of the configuration of the control and correction device 21, 22 is that of the program written in the program memory 28 and the correction value memory 29 when the pressure regulator 25 is configured as a digitally operated calculator. Using the calculator to calculate a correction value for the signals emitted by the pressure sensors 17, 18 with the help of them. At the pressure points p1 and p2, the calculator retrieves an electric value of a predetermined magnitude from the program memory 28. However, for example, both pressure sensors 17,18
It is also possible to make one of the ideal characteristic curves K and to which the other pressure sensor sends a signal to be corrected. The correction values are written in the correction value memory 29, for example, in the form of a table, and are retrieved from the correction value memory 29 during braking. Alternatively, the correction values assigned to pressure points p1 and p2 may be used to individually calculate the correction values for the other pressure points between these pressure points.

In the case of driving braking, the target value generator 23 is adjusted by the brake pedal 24. The target value generator 23 sends an electric target value signal to the pressure regulator 25. The pressure regulator 25 compares the corrected display value of the pressure sensors 17 and 18 with the target value. At the start of braking, the target value generator 23 is adjusted by the driver via the brake pedal 24,
The corrected pressure sensor display value is lower than the target value. The pressure regulator 25 recognizes this and controls the electromagnets 32, 33 via the control conductors 30, 31. The electromagnets 32, 33 switch the brake pressure adjusting valves 7, 8 from the illustrated "brake pressure decrease" position to the "brake pressure increase" position. As a result, the pressure medium flows from the pressure accumulator 14 into the wheel brake cylinders 4 and 6,
The pressure in the wheel brake cylinders 4 and 6 is increased. The pressure rise in each of these wheel brakes 4 and 6 is individually measured by the pressure sensors 17, 18 and reported to the pressure regulator 25 with the necessary corrections. This pressure regulator 25
However, when it is confirmed that the desired brake pressure is achieved because the difference between the target value and the actual value becomes small, each brake pressure adjusting valve 7 or 8 is pushed back to the “brake pressure maintaining” position, which causes The flow of pressure medium into the wheel brake cylinder is stopped. If the brake pedal 24 is only partly loosened towards the starting position, the setpoint value of the setpoint signal from the setpoint generator 23 becomes smaller. As a result, the pressure regulator 25 knows that the brake pressure is higher than the desired pressure. The pressure regulator 25 is a brake pressure regulating valve 7,
Switch 9 to the "brake pressure down" position. Pressure sensor 17,
When the actual value of the pressure signal from 18 is lowered enough,
That is, when the target value is sufficiently approached, the pressure regulator 25
Controls the brake pressure adjusting valves 7 and 8 again to the "brake pressure maintaining" position.

When the brake pedal 24 is completely released, the target value drops to zero, so that the pressure regulator 25 causes the brake pressure regulating valve 7,
Return 8 to the reference position shown in FIG. As a result, the brake pressure is released to the atmosphere through the brake pressure adjusting valves 7 and 8, and the wheel brakes are deactivated.

It should be noted that the method for compensating for the signal error of the pressure sensors 17, 18 can be used in combination with a pressure regulator different from the described pressure regulator 25.

The method of the present invention has been described in the context of a single axle pressure sensor for simplicity of description. However, normally all axles of the vehicle are braked. Therefore, there are more pressure sensors than both pressure sensors shown.
In this case, a correction value for each pressure sensor is required in order to make the left and right braking forces on each axle the same. The ideal characteristic curve K is determined by a mathematical combination, for example from the average of the measured values of all pressure sensors, or is determined by one of these pressure sensors as already mentioned.

The vehicle braking device 2 can also be configured as a skid control braking device as shown in DE-OS 2043840 mentioned at the beginning.

[Brief description of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a view showing a pressure regulator used in a vehicle brake device,
FIG. 2 is a diagram showing an actual characteristic curve and associated ideal characteristic curves of two pressure sensors forming a pair. 2 …… Vehicle brake device, 3,5 …… Wheels, 4,6 …… Wheel brake cylinders, 7,8 …… Brake pressure adjusting valve, 9,10 ……
Brake pressure conduit, 11,12,13 ... Pressure conduit, 14 ... Accumulator, 15,16 ... Measuring connection conduit, 17,18 ... Pressure sensor,
19,20 …… Measured value amplifier, 21,22 …… Control and correction device, 23
...... Target value generator, 24 …… Brake pedal, 25 …… Pressure regulator, 26,27 …… Lead wire, 28 …… Program memory, 2
9 ... Correction value memory, 30, 31 ... Control lead wire, 32, 33 ... Electromagnet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Werner Schyutunpe Kornvestheim Gelderassie-Turasse, Federal Republic of Germany 10 (72) Inventor Eberhard Weis, Hemingen Schauerhiert Schuetrase, Federal Republic of Germany 40

Claims (8)

[Claims] 1. At least one adjustable setpoint generator and at least two pressure regulating valves, wherein the pressure regulating valves form pressures in at least two separate locations, for example in wheel brake cylinders, at least substantially simultaneously. And a pressure sensor assigned to each of the points, the pressure sensor of the vehicle braking device adapted to transmit an electrical value related to the pressure acting on the pressure sensor. In the method using the pressure regulator, at least the same pressure is simultaneously supplied to all the pressure sensors (17, 18) before normal operation of the pressure regulator (25), and an electric reference value is set for each pressure. Correspondingly, find the correction value from this reference value and the value sent from the pressure sensor, and use this correction value during normal operation of the pressure regulator (25) to How to correct the displayed value, then use the brake pressure regulator for a vehicle brake system, characterized in that sending the actual pressure regulator as a value (25) Ri. 2. The method according to claim 1, wherein the pressure of the ambient atmosphere is supplied as a first pressure to all pressure sensors (17, 18) in order to determine the correction value. 3. A pressure sensor (17,1) for determining a correction value.
A method as claimed in claim 1 or 2 in which a pressure different from the pressure of the surrounding atmosphere is supplied to 8). 4. A pressure sensor (17, 18) supplied with a full height of pressure generated in a pressure accumulator (14) of a vehicle braking device (2) as a pressure different from atmospheric pressure. The method according to item 3. 5. A pressure sensor (17,1) for determining a correction value.
8. The pressure applied to 8) is made to correspond to a preselected electrical reference value taken out from the memory (28), according to any one of claims 1 to 4. the method of. 6. Vehicle braking system comprising one pressure regulator (25), at least one adjustable setpoint generator and at least two pressure regulating valves, said pressure regulating valves being separated from each other. A pressure sensor is provided at least at two points, for example at the wheel brake cylinders, at least approximately at the same time, and a pressure sensor is assigned to each of these points, which sensor is associated with the pressure acting on it. In the type that sends out an electric value, the control and correction device (21, 22) is assigned to the pressure regulator (25),
The control / compensation device (21, 22) simultaneously supplies at least one pressure of the same magnitude to all the pressure sensors (17, 18) for the purpose of compensation through the pressure regulating valve (7, 8). The correction value is detected from the difference between the electrical value sent from the pressure sensor and the at least one associated reference value, and the pressure sensor (17,18) is supplied during normal operation of the pressure regulator. The vehicle braking device is characterized in that the value sent from (1) is corrected according to the correction value and is supplied to the pressure regulator (25) as an actual value. 7. A control and correction device (21, 22) is a memory (28, 2).
9. A vehicle braking system according to claim 6, consisting of a programmed calculator with 9). 8. Vehicle braking system according to claim 7, in which the calculator is combined with the pressure regulator (25) in one component unit.