JPH05162628A - Pressure controller of wheel brake - Google Patents

Abstract

PURPOSE:To improve the responsiveness a fluid pressure controller and simplify its structure by providing an opening/closing valve at a main brake fluid passage, a switching valve and a relief valve across the main brake fluid passage and an open passage, and a check valve at a suction passage. CONSTITUTION:An opening/closing valve 16 is closed during operating a TCS (traction control system), and a switching valve 30 is kept open because fluid pressure is not generated in a master cylinder 10. With this constitution, pressure fluid is fed from a master cylinder reservoir 18 through an open passage 23, a suction passage 21 is fed to a wheel cylinder 11 through a discharge passage 22, and the feed valve 12 of a main brake fluid passage 20 by a fluid pressure pump 15. Then the opening/closing of the feed valve 12 and the discharge valve 14 is repeated to control accelerating slip. At this time, because pressure fluid does not flow out to the master cylinder 10 side, the pressure in the discharge passage 22 increases, and then the opening/closing operation of a relief valve 50 is repeated to adjust the pressure. Besides, fluid which is discharged from the discharge valve 14 flows to the open passage 23 through the reservoir 13, the suction passage 21, and the check valve 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has both an anti-lock control function (ABS) for preventing wheel lock during braking and a traction control function (TCS) for preventing drive wheel slip during start and acceleration. The present invention relates to a pressure control device for a wheel brake.

[0002]

2. Description of the Related Art A vehicle equipped with both ABS and TCS functions incorporates a pressure control device as disclosed in JP-A-57-22948. This device is AB
The S hydraulic circuit is used as a basic circuit, and a control valve that operates according to the operation of the master cylinder and a hydraulic pump for TCS are additionally provided in the return line of this circuit. This control valve communicates between the supply / discharge switching valve and the reservoir when the master cylinder is operating, shuts off the communication between the supply / discharge switching valve and the reservoir when not operating, and the supply / discharge switching valve and the discharge side conduit of the hydraulic pump. Functions to communicate with and. In addition, the hydraulic pressure source during ABS operation and TCS operation is commonly found for hydraulic pumps.
During CS operation, the hydraulic pressure from the hydraulic pump is supplied to the wheel cylinder of a predetermined wheel through the supply / discharge switching valve through the return line of the ABS hydraulic circuit.

[0003]

The above-mentioned conventional pressure control device has the following problems.

<B> At the time of pressure increase / decrease by TCS operation, the supply of hydraulic pressure from the hydraulic pump to the wheel cylinder and the discharge of pressure from the wheel cylinder to the reservoir respectively require at least two valves, a control valve and a supply / discharge switching valve. It must be routed through, its configuration is complicated, and its responsiveness is poor.

<B> The hydraulic pump not only requires the pump piston for the TCS in addition to the pump piston for the ABS, but also requires the solenoid valve for two positions and three directions, which complicates the structure. The equipment becomes expensive.

<C> During TCS operation, the hydraulic pump sucks the hydraulic fluid in the master cylinder reservoir and supplies the discharged hydraulic fluid to the wheel cylinders to increase the hydraulic pressure. Recirculates the pressure liquid in the wheel cylinder to the master cylinder reservoir via the master cylinder conduit and the master cylinder. Therefore, the cylinder cup in the master cylinder is easily damaged.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide the following pressure control device for a wheel brake. <A> A wheel brake pressure control device that improves the responsiveness of hydraulic pressure control during TCS operation. <B> A wheel brake pressure control device that can reduce the number of parts and simplify the configuration. <C> Wheel brakes that can prevent damage to the master cylinder cylinder cup
Pressure control device.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a main brake passage connecting a master cylinder and a wheel cylinder, and a main brake passage interposed between the master cylinder and the wheel cylinder to open and close the communication between the master cylinder and the wheel cylinder and also to connect the wheel cylinder. Supply / exhaust switching valve that opens and closes the communication between the pump and the reservoir, an intake flow path that connects the intake side of the hydraulic pump and the reservoir, a main brake flow path on the master cylinder side of the supply / exhaust switching valve, and the hydraulic pump. In a pressure control device for a wheel brake, which is provided with a discharge flow path for connecting to and from, a master cylinder side is interposed from a connection part of the main brake flow path with the discharge flow path, and is closed only when the traction control is operated. A 2-position 2-way switching valve that switches, an open flow path that connects the master cylinder reservoir and the intake flow path, and a main brake flow path and an open flow path A hydraulically operated switching valve that receives the operating pressure of the master cylinder to switch the open flow path to the closed state, and is installed across both the main brake flow path and the open flow path. When the traction control is activated and the pressure in the discharge channel reaches a certain value or more, the master cylinder pressure is received in the master cylinder pressure, and the pressure in the discharge channel is received in the other. It is configured to add a relief valve that discharges to the passage and maintains a closed state at other times, and a check valve that is interposed on the reservoir side from the connection portion of the suction passage with the open passage. It is a characteristic pressure control device for wheel brakes.

[0009]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings.

<B> Basic Circuit FIG. 1 shows an example of the pressure control device. The pressure control device includes a main brake flow passage 20 that connects the master cylinder 10 to the wheel cylinder 11, a normally-open type supply valve 12 that opens and closes the communication of the main brake flow passage 20, and a reservoir 13 that can store hydraulic fluid. A normally closed discharge valve 14 that opens and closes the communication between the main brake flow path 20 and the reservoir 13, a hydraulic pump 15 that operates during ABS operation, and an intake flow that connects the intake side of the hydraulic pump 15 and the reservoir 13. A basic circuit is an ABS hydraulic circuit constituted by a passage 21 and a discharge passage 22 that connects the discharge side of the hydraulic pump 15 and the main brake passage 20. The pressure control device according to the present invention is configured by adding the following elements to the above circuit.

<B> The open / close valve 16 is an electromagnetic open / close valve that closes the main brake flow passage 20 only when the TCS is in operation.
It is interposed on the master cylinder 10 side from the connecting portion with.

<C> The open flow path 23 is an open flow path and connects the master cylinder reservoir 18 and the suction flow path 21.

<D> The changeover valve 30 is a changeover valve, which is interposed between the main brake circuit 20 and the open flow path 23. The switching valve 30 receives the hydraulic fluid pressure of the master cylinder 10 and receives the master cylinder reservoir 18
It is a hydraulically operated valve that closes the communication between the suction passage 21 and the suction passage 21. The structure of the switching valve 30 will be described with reference to FIG. 2. A piston 32 is slidably accommodated in a cylinder 31, and independent chambers 31a and 31b are defined on both sides of the piston 32 in the cylinder 31. There is. One chamber 31
A stopper 33 is formed at the end of the piston 32 located inside a, and a push rod 35 having a valve ball 34 at the tip is formed at the end of the piston 32 located inside the other chamber 31b. The piston 32 is constantly urged toward the chamber 31a side by receiving the spring force of a spring 36 compressed inside the chamber 31b. Further, the liquid passage ports 31c to 31 are respectively provided in the chambers 31a and 31b.
f is provided, and the ports 31a to 31f communicate with the illustrated flow paths 20 and 23, respectively. A valve seat 37 is formed at the end of the chamber 31b communicating with the liquid passage port 31e.
The valve ball 34 and the valve seat 37 constitute a normally-open type valve mechanism. In this valve mechanism, the force that pushes the piston 32 generated in the chamber 31a toward the chamber 31b is generated by the spring 36 in the other chamber 31b. When the spring force is exceeded, the piston 32 moves to the left in the figure and closes the flow path.

<E> The relief valve 50 is a relief valve, which is the main brake flow passage 20 and the open flow passage 2.
It is installed across three. The relief valve 50 receives the pressure of the master cylinder 10 on one side and the pressure of the discharge passage 22 on the other side, and releases the excess hydraulic pressure only when the pump discharge hydraulic pressure exceeds a predetermined value during TCS operation. Road 23
It is composed of a hydraulically-operated normally closed valve that discharges to the outside and maintains the closed state at other times. The relief valve 50 is especially TCS
By the pressure liquid discharged by the hydraulic pump 15 during operation,
The discharge passage 22 and a part of the main brake passage 20 connected to the discharge passage 22 function so as not to apply an unnecessary hydraulic pressure. The relief valve 50 will be described in detail with reference to FIG. A piston 52 is slidably accommodated in the cylinder 51, and independent chambers 51a and 51b are defined inside the cylinder 51 on both sides of the piston 52, respectively. Piston 52
Receives the spring force of the spring 56 compressed in the chamber 51a, and the chamber 5
A valve ball 54 is projectingly provided at the end of the piston 52 located in the chamber 51b while being constantly urged toward the 1b side.
Further, the liquid passage ports 51c to 51c and 51b
51g is provided, and the ports 51a to 51g are in communication with the illustrated flow paths 20, 22, and 23, respectively. On the other hand, a valve seat 57 is formed at the opening of the port 51g to the chamber 51b, and the valve ball 54 and the valve seat 57 constitute a normally closed valve mechanism. When the force pressing the valve ball 54 portion due to the hydraulic pressure of the discharge flow passage 20 in the pressure state exceeds the spring force of the spring 50, the flow passage is opened, and when the chamber 51a is under pressure, the closed state is maintained. When using a relief valve that pushes the piston only with a normal spring force, an opening / closing valve for preventing the discharge of the pressure liquid in the discharge flow path 22 to the open flow path 23 at the time of normal braking and ABS operation is provided as a separate discharge flow path. Two
Although it is necessary to interpose it on the second valve, the on-off valve as described above can be omitted by using the relief valve mechanism of the present invention.

<F> The check valve 40 is a check valve, which is provided on the reservoir 13 side of the connection portion of the suction passage 21 with the open passage 23.
From the liquid pressure pump 15 to the open flow path 23 is allowed.

<G> Valve The supply valve 12, the discharge valve 14, and the opening / closing valve 16 are all solenoid valves with two positions and two directions. Supply valve 12 and discharge valve 14
Is opened and closed by repeating excitation and demagnetization during ABS operation or TCS operation, and the on-off valve 16 is excited only during TCS operation to close the flow path. Each of these valves 12, 14, 16
The operation of is controlled individually by a controller (not shown).

[0017]

Next, the operation will be described with reference to FIG.

<a> In the non-operating state In the non-operating state, the on-off valve 16 and the supply valve 12 are open and the discharge valve 14 is closed. Since the switching valve 30 does not generate pressure in the master cylinder 10, the piston 3
2 is biased by spring 36 to open the valve mechanism. The piston 52 of the relief valve 50 receives the spring force of the spring 56 to close the valve mechanism. The hydraulic pump 15 is in a non-operating state.

<B> Normal Braking During normal braking in which the wheels do not tend to lock, the open / close valve 16 and the supply valve 12 are kept open, and the discharge valve 1
4 remains closed and the hydraulic pump 15 is inactive. The pressure generated in the master cylinder 10 is supplied to the wheel cylinder 11 through the switching valve 30, the relief valve 50, the opening / closing valve 16 and the supply valve 12 through the main brake flow path 20 to start braking of the wheel. At this time, the switching valve 30
When the rising hydraulic pressure of the master cylinder 10 exceeds the spring force of the spring 36, the piston 32 is moved to the left side in the drawing to close the valve function.

<C> ABS operation During the ABS operation, the open / close valve 16 is kept open, the switching valve 30 receives the pressure fluid from the master cylinder 10 to close the valve mechanism, and the relief valve 50 is the master valve. The pressure receiving area of the piston 32 that receives the pressure of the cylinder 10 is
Since the pressure receiving area is larger than the pressure receiving area, the valve mechanism maintains the closed state. In this state, the supply valve 12 and the discharge valve 14 are repeatedly operated to prevent the wheels from being locked.
1 is pressure-reduced, maintained, and pressure-increased. Further, during the ABS operation, the hydraulic pump 15 sucks the liquid discharged from the wheel cylinder 11 to the reservoir 13 via the discharge valve 14 and supplies the liquid to the main brake flow passage 20 again.

<D> During TCS operation The on-off valve 16 switches to the closed state during TCS operation, and no hydraulic pressure is generated in the master cylinder 10. Therefore, the switching valve 3
0 remains open. In this state, the hydraulic pump 15 starts operating, sucks the liquid from the master cylinder reservoir 18 through the open flow path 23 and the suction flow path 21, and discharges the pressurized liquid from the master flow path 22 and the supply valve 12 of the main brake flow path 20. Is supplied to the wheel cylinder 11 of the drive wheel via a brake to actuate the brake to suppress acceleration slip of the drive wheel. After that, supply valve 1
2 and the discharge valve 14 are repeatedly opened and closed to reduce, maintain, and increase the pressure of the wheel cylinder 11 of the drive wheel to control the acceleration slip. Since the on-off valve 16 maintains the closed state during the TCS operation, the hydraulic fluid discharged from the hydraulic pump 15 does not flow out to the master cylinder 10 side in the non-pressurized state through the main brake flow passage 20. Further, since no pressure is generated in the master cylinder 10 during the TCS operation, the chamber 51a of the relief valve 50 is in a non-pressurized state, and the piston 52 is merely acted by the spring force of the spring 56 as a force in the valve closing direction. .. Therefore, when the pressure of the discharge flow path 22 rises and the force pushing the valve ball 54 of the piston 52 exceeds the spring force of the spring 56, the piston 52 shifts to the right in the drawing to temporarily open the valve mechanism, The pressure in the flow path 22 decreases.
When the pressure in the discharge passage 22 decreases and the force pressing the valve ball 54 becomes less than the spring force of the spring 56, the piston 56 shifts to the right in the drawing and closes the valve mechanism. The relief valve 50 repeats the above-described opening / closing operation to adjust the pressure of the hydraulic fluid discharged from the hydraulic pump 15 to a predetermined value. On the other hand, the liquid discharged from the discharge valve 14 passes through the reservoir 13 and the suction flow passage 21 and the open flow passage 23 that is in communication with the master cylinder reservoir 18.
Contact.

[0022]

Other Embodiments FIGS. 3 and 4 show a valve device 60 in which the switching valve 30 and the relief valve 50 are integrated.

<A> Configuration This valve device 60 is slidably mounted on a cylinder 61 having different diameters, a switching valve ring piston 62 slidably arranged in the cylinder 61, and an axial center of the ring piston 62. It is composed of a piston 63 for a relief valve inserted therein. By accommodating both pistons 62 and 63 in the cylinder 61, the inside of the cylinder 61 is divided into two chambers 61a and 61b. A valve ball 63a is formed at the end of the piston 63 exposed in the chamber 61b, and a liquid passage port 61g facing the valve ball 63a.
The first valve mechanism is formed by the valve seat 64 and the valve ball 63a formed at the inlet of the valve. The piston 6 is placed in one chamber 61a.
A first spring 65 for urging the valve 3 in the valve closing direction is contracted. Further, an inclined surface 62a, which is a valve body, is formed at the end of the ring piston 62 exposed in the chamber 61b, and a valve seat 67 is formed at the step portion of the cylinder 61 facing the inclined surface 62a. The valve seat 67 forms a second valve mechanism. A second spring 66 that urges the second valve mechanism in the valve opening direction is contracted between the chamber 61b and the ring piston 62. The rear end of the ring piston 62 contacts the stepped surface of the cylinder 61, and the return position is regulated.

<B> Operation First, the operation of the ring piston 62 will be described. When no pressure is generated in the master cylinder 10 (non-braking and TCS operation), as shown in the figure, the ring piston 6
2 is urged by the second spring 66 to open the second valve mechanism, so that the master cylinder reservoir 18 and the intake passage 21
Are in communication. Further, during normal braking and ABS operation, when the pressure of the master cylinder 10 reaches a predetermined value or more, the ring piston 62 moves to the left side in the drawing against the second spring 66 and closes the second valve mechanism to close the master valve. The communication between the cylinder reservoir 18 and the suction flow passage 21 is cut off. Next, the operation of the piston 63 will be described. Piston 63
The piston 6 resists the first spring 65 only when the pressure in the discharge passage 22 reaches a predetermined value or more during TCS operation.
3 is moved to the right side of the drawing, the first valve mechanism is opened, and excess pressure liquid is discharged to the open flow path 23. At other times, it remains closed.

[0025]

Since the present invention is as described above, the following effects can be obtained.

<A> Since the hydraulic pressures from the hydraulic pump and the wheel cylinders are supplied and discharged only through the supply / discharge switching valve during the pressure increase / decrease during TCS operation, the response is good.

<B> Since the ABS hydraulic pump can also be used for the TCS, it is not necessary to add a hydraulic pump component for the TCS.

<C> During TCS operation, when the pressure is increased, the liquid is sucked from the master cylinder reservoir, and when the pressure is reduced, the liquid discharged from the wheel cylinder is returned to the master cylinder reservoir through the open flow path, and the inside of the master cylinder is discharged. It is configured not to pass through. Therefore, the piston cup in the master cylinder can be protected from damage.

<D> A TCS function having good performance and high reliability can be provided only by adding a 2-position 2-way electromagnetic on-off valve and a hydraulically operated valve to the ABS basic circuit.

[Brief description of drawings]

FIG. 1 is a block diagram of a pressure control device according to the present invention.

FIG. 2 is an enlarged sectional view of a switching valve and a relief valve.

FIG. 3 is an explanatory diagram of another embodiment.

FIG. 4 is an enlarged sectional view of a valve device having both a switching valve function and a relief valve function.

Claims (1)

[Claims] 1. A main brake flow path connecting a master cylinder and a wheel cylinder, and a main brake flow path interposed therebetween.
A supply / discharge switching valve that opens and closes the communication between the master cylinder and the wheel cylinder and also opens and closes the communication between the wheel cylinder and the reservoir, a suction flow path that connects the suction side of the hydraulic pump and the reservoir, and a supply / discharge switching In a pressure control device for a wheel brake, which includes a main brake flow passage on the master cylinder side of a valve and a discharge flow passage connecting a hydraulic pump, a master cylinder side from a connection portion with the discharge flow passage of the main brake flow passage And a two-position two-way on-off valve that switches to a closed state only during traction control operation, an open flow passage that connects the master cylinder reservoir and the intake flow passage, and both the main brake flow passage and the open flow passage. A hydraulically operated switching valve that is installed across the flow passage and receives the operating pressure of the master cylinder to switch the open flow passage to the closed state, and both the main brake flow passage and the open flow passage. It is installed across the road, receives master cylinder pressure on one side and discharge passage pressure on the other side, and switches to the open state when the discharge passage pressure reaches a specified value or more during traction control operation. To discharge excess fluid pressure in the discharge channel to the open channel,
Wheels characterized by additionally comprising a relief valve that maintains a closed state at other times and a check valve that is interposed on the reservoir side from the connection portion of the intake passage with the open passage. Brake pressure control device.