JPS6171258A - 2-system brake circuit associated with anti-lock device - Google Patents

Abstract

PURPOSE:To achieve high deceleration even upon pressure droppage by providing output pressure booster means for boosting the output pressure of reducing valve at the live system on the basis of detected information from pressure droppage detecting means arranged between pressure generating source and modulator. CONSTITUTION:Means 3 for detecting the system at the pressure drop side through detection of pressure difference between respective system is arranged between tandem master cylinder 1 and modulators 4, 4' of anti-lock system. While bypaths are provided respectively in parallel with the reducing valve 6, 6' in respective system and normal close bypath opening means 7, 7' are provided in said bypaths. On the basis of pressure droppage detect information from said means 3, the bypath opening means 7, 7' in normal side system are opened to open the normal side bypath.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a pressure reducing valve for approximating the braking force distribution of a vehicle to an ideal state, and a pressure reducing valve that automatically adjusts the braking force of the vehicle to control the slip state of the wheels. The present invention relates to a two-system control circuit for a vehicle having an anti-lock device.

Prior art and its problems A so-called anti-lock device detects the rotational speed of the wheel during braking and automatically adjusts the braking force separately from the MI power generated by the driver to control the slip state of the wheel. widely known. On the other hand, for safety reasons, it is common for vehicles to have two independent braking circuits, and various types of braking circuits are used, such as I+ piping that is divided into front and rear wheel systems, X piping shown in Figure 4, and JJ piping shown in Figure 3. Piping type is applied. In addition, in order to approximate the distribution of braking force between the front and rear wheels of the vehicle to an ideal state, a pressure reducing valve F is provided between the pressure source and the rear wheel brake, which reduces the input pressure above a certain pressure (break point) and outputs it. In this case, there are two pipes connecting the pressure source and the rear wheel brake, such as the X pipe and JJ pipe mentioned above.
If there are systems, each system is provided with a pressure reducing valve. In addition, if one of the two systems fails due to a liquid leak or the like and is no longer pressurized, the output pressure of the residual pressure valve of the surviving system can be made higher than normal to increase the ultimate deceleration. This is common, and in that case, by arranging two systems of pressure reducing valves in one case song and comparing the input pressure introduced into each system, the output pressure of the surviving pressure reducing valve can be determined in the event of a failure of one system. Two-system pressure valves with a so-called failure compensation function that generate high pressure are widely known, and many systems have been proposed, including Japanese Utility Model Publication No. 57-36521.

On the other hand, the anti-lock Vi T1. When applying the 4-channel system, a mononitrator of the anti-lock device that adjusts the input pressure and outputs it is installed immediately before the brakes of the four wheels. Dual use at the same time with the mononitrator! In addition to the 3-channel system, which aims to achieve economical effects, there is also a 2-channel system. In that case, as shown in the case of the X piping in FIG. Front wheel brake 5.5'-% respectively, left and right i;T
The braking pressure of the wheel brakes 5.5 is simultaneously controlled by the first modulator 4, and both systems are supplied from the master cylinder 1 to the second mononitrator 4 via the pressure reducing valve 6.6', similarly to the front wheels. Two systems at the same time? ) If, the brakes are guided to the left and right rear wheel brakes 8.8', respectively. In this case, it is preferable that the pressure reducing valve 6.6' is a pressure reducing valve with failure compensation function as described above.
Since both of the second monoulators equally control the braking pressures of the left and right wheels at the same time, even if the positions of the pressure reducing valves 6, 6' and the second module brake 4 are reversed, the fault compensation of the pressure reducing valves is compensated for during normal operation. There is no problem in which the effect is exhibited.

However, with such a two-channel anti-lock device that simultaneously controls the front and rear left and right wheels, if the left and right wheels are braked on a road surface with different coefficients of friction, one of the wheels will be affected. Since the braking pressure of both the left and right wheels is controlled simultaneously, the side that is not focused on is not optimally controlled, which improves the directional stability, maneuverability, and stopping distance of the vehicle compared to when the left and right front wheels are controlled individually. There are problems with this.

Therefore, as shown in Fig. 1, two-channel anti-lock control (■) for the There is a system in which the system is branched to the rear wheel system, one is led directly to the front wheel brake 5 on one side, the other is connected to the rear wheel brake 8 on the other side via the pressure reducing valve 6, and the other system is configured in exactly the same way. Proposed.

In this case, the above-mentioned problem is solved because the left and right front wheels, which share a large amount of braking force, can be independently controlled.

However, in the case of this system, the hydraulic pressures of the two systems are controlled independently after passing through the mononitrator 4°4, so
Two hydraulic chambers 2, 2' of tandem master cylinder 1
Even under normal conditions, when the two systems of hydraulic pressure generated by Different systems have different signal values, and while the anti-lock control is maintained, the difference in the manual pressure of the pressure reducing valves 6, 6' between the two systems fluctuates greatly. Therefore, the pressure reducing valve 6.6'
If it is the above-mentioned failure compensation function/-t2 system pressure reducing valve, the failure compensation function will act intermittently even in normal conditions, and the braking pressure of t& will be increased to an irregular value, resulting in anti-lock control. The problem is that it becomes extremely difficult.

This problem is not limited to the case of the X piping, but is a common problem when the JJ piping shown in Figure 3 has two braking circuits in which the output pressure from the anti-lock device's monoulator is introduced to the brake via a pressure reducing valve. It is a point. In this case, in order to avoid the above-mentioned malfunction, the failure compensation function is removed from the pressure reducing valve,
It may be possible to have the pressure reducing valve on the surviving side output the same pressure as during normal operation even if the L system fails, but this would result in a gap between the ideal distribution of braking force and the This results in the problem that the final deceleration is low.

The purpose of the present invention is to solve these problems. Under normal conditions, the anti-lock device does not cause irregular fluctuations in braking pressure, and when one system fails, the surviving side can This invention provides a two-system control control circuit with an anti-lock device that makes the braking pressure of a brake connected to a pressure reducing valve higher than that under normal conditions to obtain higher deceleration.

Means for Solving the Problems In order to achieve the above object, the present invention provides a braking circuit comprising two braking circuits in which the pressure generation source is dedicated to the modulator of the anti-lock device, and the output pressure is guided to the brake via a pressure reducing valve. First, failure detection means for each system was provided between the pressure generation source and the monolayer.

As a result, it is possible to detect a failure state in one system regardless of the operation of the mononulator of the anti-lock device T, and a failure state in one system due to the differential pressure between the two systems due to the operation of the mononulator even in normal conditions. This makes it possible to prevent false detections. Second, output pressure increasing means was provided to detect the system on the failed side based on the information from the failure detection means and to increase the output pressure of the pressure reducing valve of the surviving system. As a result, only when one system fails, the braking pressure of the brake to which the output pressure of the pressure reducing valve of the surviving system is guided can be made higher than that under normal conditions, and the above object can be achieved.

Embodiment Figure 1 shows an example in which the present invention is applied to a two-system control circuit for X piping, in which the present invention is applied between the tandem master cylinder 1 and the modulators 4 and 4' of the anti-lock device installed in each system. A failure detection means 3 is provided to detect the system on the failure side by detecting the pressure difference between each system, and a pressure reducing valve 6,
A bypass circuit is provided in parallel with each h bypass path 6', and bypass path opening means 7 and 7' are provided in this circuit to open the surviving bypass path according to the information from the failure detection means 3. The output pressure of the surviving residual pressure valve is made equal to the input pressure only in the event of a system failure.

As shown in U.S. Pat. No. 3,480,333, the failure detecting means 3 applies hydraulic pressure to both 8' and 41 systems of the differential piston so that this piston moves to the failure side when the l system fails. A method of detecting a failure is considered, and the bypass passage opening means 7 is provided with a means for closing the bypass passage on the piston, and the closed state is released by the movement of this piston when the l system failure occurs. Mechanical means can be considered to do this. Further, in this embodiment, failure detection means 3. Modulator-4, 4', pressure reducing valve 6.6'
, and the output pressure increasing means 7.7 can be integrally laid out in one casing to facilitate on-vehicle installation.

Figure 2 shows an example in which the present invention is applied to a two-system control circuit for X piping, similar to Figure 1, and has many parts in common with Figure 1, except for the tandem master turn cylinder l and anti-lock device. Independent failure detection means 3.3' are provided in each system between the modulator 4.4' and the pressure reducing valve 6.
, 6 is provided so as to bypass not only the pressure reducing valves 6, 6' but also the modulators 4, 4' of the anti-lock device, and the output pressure increasing means 7.7 is used to maintain the survival side in the event of system failure. The difference is that the anti-lock device is also disabled. Also, one point in this figure is νp.
indicates an electric circuit, in which the failure detection means 3, 3 are electrical pressure sensors, and the pressure of each system is converted into an electric signal and guided to the controller 9 constituting the anti-lock device, and the pressure of each system is The faulty system is detected by comparing the output pressure increasing means 7, 7 with normally closed solenoid valves, and if both systems are normal, the mononitrators 4, 4' and the pressure reducing valve 6. An electrical means is conceivable in which the bypass path to 6' is closed, and only when the 1 system fails, the surviving solenoid valve is opened by an electric signal from the controller 9 to open the bypass path. It goes without saying that the controller 9 and the modulators 4.4 of each system are electrically connected.

Figure 3 shows an example in which the present invention is applied to a two-system control circuit for JJ piping, which is provided integrally with the tandem master cylinder ■ and detects the overstroke of the piston in the tandem master cylinder when the first system fails. The system is equipped with a fault detection means 3 for detecting the system on the faulty side, and the hydraulic pressure of each system is transmitted to the front wheel system and the rear wheel system after passing through the modulators 4 and 4' of the anti-lock device. The front wheel system is led to the hydraulic pressure chambers on one side of both the left and right front wheel brakes 5, 5, each having two independent hydraulic chambers, while the rear wheel system is led to the hydraulic pressure chambers on one side of each of the left and right front wheel brakes 5, 5, which have two independent hydraulic chambers, while the rear wheel systems are respectively guided to the rear through pressure reducing valves 6, 6. Wheel plate 8.8
be led to. At this time, the surviving side of the pressure reducing valves 6, 6 is electrically or mechanically driven by the failure information of the l system obtained by the failure detection means 3, and the pressure reducing action of the pressure reducing valves 6゜6' is disabled. Alternatively, the pressure reducing valves 6, 6 (14) are equipped with output pressure increasing means 7, 7' for making the output pressure on the survival side higher than the normal state by increasing the height in the valve opening direction for the pressure-responsive valve bodies comprising the pressure reducing valves 6, 6 (14). The output pressure increasing means 7.7 for inactivating the pressure reducing action of the pressure reducing valve on the surviving side includes:
For example, as shown in Japanese Patent Application Laid-open No. 54-123666, during normal operation, the pressure reducing valves of each system are allowed to operate while remaining at the neutral position, and when one system fails, the valves are moved to the axial direction. J
A piston is installed to disable the residual pressure valve on the survival side,
There is a method in which failure information obtained by the failure detection means 3 is guided to a 5h magnetic coil as an electric signal via a controller (not shown), and the piston is driven in the axial direction by the electromagnetic force of the electromagnetic coil.

Further, as a specific example of the output pressure increasing means for increasing the bias force in the valve opening direction with respect to the pressure responsive valve element constituting the pressure reducing valve, one end is gathered at the pressure responsive valve element, and this valve element is A spring is provided which determines the pressure at which the pressure reducing action of the pressure reducing valve starts. A piston is engaged with the other end of the spring, and when a system failure occurs, the piston is activated by the electric force of the excitation coil, etc. A method of increasing the output pressure by increasing the pressure in the valve opening direction of the valve body by moving the seven throat length of the valve in the direction of compression, thereby increasing the pressure at which the depressurization action starts compared to the normal state % formula % or more As explained above, according to the present invention, after the pressure is released directly from the pressure generating source through the mononitrator, the braking circuit is connected to the braking circuit 2, which is compressed by the residual pressure by the pressure reducing valve and then sent to the brake.
In a two-system control circuit with an anti-lock device that controls the left and right front wheels separately, such as X piping and JJ piping, one system is installed between the pressure generation source and the control circuit. The system detects the loss of fat in the vehicle, uses that information to increase the output pressure of the pressure reducing valve on the surviving side, and increases the operating pressure of the surviving side's brakes, allowing anti-lock control to be performed independently on the left and right front wheels. In addition, the malfunction detection means will not malfunction due to the differential pressure based on the operation of the two independent anti-lock devices during normal operation.
In addition, (2) a high ultimate deceleration can be obtained by reliably increasing the operating pressure of the surviving brake in the event of a system failure.

[Brief explanation of drawings]

FIG. 4 is a brake circuit diagram showing the prior art, and FIGS. 1, 2, and 3 are brake circuit diagrams of embodiments of the present invention. 1. Kundem master turn ring 2, 2', hydraulic pressure generation chamber 3 of each system, failure detection means 4, 4', anti-lock device modulator 5
, 5', - Front wheel brake 6.6', - Pressure reducing valve 7.7', - 1 Output pressure increasing means 8, 8, - 1 Rear brake 9, - Controller Fig. 4

Claims (8)

[Claims] (1) A source of braking pressure, a pressure reducing valve that reduces the input pressure and outputs it, a brake to which the pressure reduced by the pressure reducing valve is input as operating pressure, and an anti-lock device that controls the slip state of the wheels. and a modulator that is provided between the pressure generation source and the pressure reducing valve and that adjusts and outputs the input pressure from the pressure generation source. Failure detection means for each system is provided between the pressure generation source and the modulator, and when one of the systems fails, the system on the failure side is detected, and the information from this failure detection means is used to detect the failure. A two-system control control circuit with an anti-lock device, comprising an output pressure increasing means for increasing the output pressure of the pressure reducing valve of the surviving system to a higher pressure than when both systems are normal. (2) The failure detection means is characterized in that the system on the failure side is detected by detecting a pressure difference between the two systems from the pressure generation source to the modulator. A two-system control circuit with an anti-lock device according to claim 1. (3) The failure detection means detects the system on the failure side by detecting an overstroke of a piston in a tandem master cylinder at the time of failure. A two-system control circuit with an anti-lock device as described in Scope 1. (4) The output pressure increasing means closes the bypass path provided in parallel to the surviving pressure reducing valve when both systems are normal, and opens it only when one system fails. A two-system control circuit with an anti-lock device according to claim 1, 2, or 3, characterized in that the circuit is a dual-system control circuit with an antilock device. (5) The output pressure increasing means closes the bypass passage provided in parallel with the modulator and the pressure reducing valve on the survival side when both systems are normal, and opens only when one system fails. A two-system control circuit with an anti-lock device according to claim 1, 2, or 3, characterized in that the circuit is configured to: (6) The anti-lock according to claim 1, 2 or 3, wherein the output pressure increasing means disables the pressure reducing valve on the surviving side. Two-system control circuit with device. (7) When one system fails, the output pressure increasing means increases the bias force in the valve opening direction on the pressure-responsive valve element of the surviving pressure reducing valve compared to when both systems are normal. A two-system control circuit with an anti-lock device according to claim 1, 2, or 3, characterized in that the circuit is configured to: (8) The failure information detected by the failure detection means is transmitted as an electric signal to the controller constituting the anti-lock device, and the output voltage increasing means when one system fails due to the electric signal from the controller. Two systems with an anti-lock device according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: control circuit.