JPH066148U - Brake switching valve device - Google Patents

Abstract

(57) [Abstract] [Purpose] As a switching valve device for a brake, it is intended to prevent communication between the first and second inlets even during movement of the piston. [Composition] When the piston 500 is in the middle of movement and both the first and second valve portions 711 and 712 are open, the communication between the first inlet 201 and the second inlet 202 is blocked. Auxiliary valve portions 811 and 812 are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brake switching valve device capable of selectively connecting either a master cylinder or a pressure generating source other than the master cylinder to a wheel cylinder, and more particularly to a technique for preventing pressure leakage during switching.

[0002]

[Prior art and its problems]

 Various techniques have already been known for automating brake control of vehicles and the like. For example, JP-A-63-78300 or JP-A-58-15300 discloses a technique for preventing a rear-end collision or maintaining a safe inter-vehicle distance with a vehicle traveling ahead. It's clear that anti-skid control and traction control technologies are now common in real vehicles. When performing such various brake controls, it is conceivable to switch the pressure to the wheel cylinders by a switching valve device. That is, the idea is to switch between the pressure system by the master cylinder based on the normal pedal operation and the controlled pressure system by another pressure generation source for automatic control.

When applying such a switching system, a switching valve device capable of selectively connecting two pressure systems to the wheel cylinder is required. As this switching valve device, a first inlet connected to the master cylinder, a second inlet connected to a pressure source different from the master cylinder, an outlet connected to the wheel cylinder, and this outlet, And a pair of holes that communicate with the first and second inlets, and that can open and close the communication between the first inlet and the outlet and the communication between the second inlet and the outlet. And a pair of valve portions arranged in the hole to receive the first inlet-side pressure and the second inlet-side pressure in opposition to each other, and to respond to the difference in acting force between the two pressures. A known one provided with a piston that reciprocates between a first position in which one is closed and the other is opened and a second position in which one valve portion is opened and the other valve portion is closed (for example, the actual opening 58). No. 44528) can be used.

However, if this known one is used, both of the pair of valve portions open during movement of the piston, and the first and second inlets communicate with each other, so that one of the two inlets is connected. It was found that the pressure supplied to the inlet leaks to the other inlet side and the rise of the outlet pressure is delayed. In particular, this problem becomes more noticeable when the moving speed of the piston is slower due to the moderate increase in the inlet pressure.

[0005]

[The purpose of the device]

 An object of the present invention is to provide, as a switching valve device for a brake, a technique for preventing communication between the first and second inlets even during movement of the piston.

[0006]

[Means and actions therefor]

 In this invention, an auxiliary valve portion is provided to prevent communication between the first inlet and the second inlet when the piston is moving and both the first and second valve portions are open. I am trying to do it. As the auxiliary valve portion, a spool type valve having a piston as a valve element and configured around the piston is preferable. As described above, in this invention, even if the pair of valve portions are simultaneously opened during the movement of the piston, the auxiliary valve portion prevents the pressure from leaking between the inlets.

[0007]

【Example】

 FIG. 1 is a brake piping diagram showing an overall configuration of a brake system including a switching valve device of the present invention. First, referring to this Fig. 1, the overall picture of the braking system will be clarified. The braking system shown in FIG. 1 comprises two pressure sources. One of the pressure generation sources is a tandem master cylinder 10. The master cylinder 10 is integrated with the booster 12, and they are operated by depressing the brake pedal 14. The master cylinder 10 also includes two discharge ports 10a and 10b. The discharge port 10a is a supply port to one system 20 of the X-type brake pipe, and the discharge port 10b is a supply port to the brake pipe 30 of the other system. The brake piping is a 4-channel type, each of which is independent. Therefore, the wheel cylinders of the left front brake 40FL and the right rear brake 40RR are located at the end of the one brake pipe 20, and the wheel cylinders of the right front brake 40FR and the left rear brake 40RL are located at the end of the other brake pipe 30, respectively. Moreover, switching valve devices 100, which will be described later, are arranged on the way to the respective wheel cylinders.

The other pressure source is composed of a pump unit 50 and a proportional solenoid valve 60. The pump unit 50 includes a pump 52 driven by a motor 51, an accumulator 53 that stores the pressure (fluid pressure) generated by the pump 52, and the like. This pump unit 50 stores the pressure of a predetermined pressure in the accumulator 53 by controlling the drive of the pump 52, like the one used in the hydro-booster or anti-skid control device. The hydraulic fluid of the pump unit 50 is supplied from the reservoir 11 of the master cylinder 10.

The pressure from the pump unit 50 is supplied to each proportional solenoid valve 60 and the wheel cylinder of each brake through a brake pipe 70 different from the brake pipes 20 and 30 communicating with the master cylinder 10. It has become so. The proportional solenoid valve 60 has a function of appropriately controlling the brake fluid pressure for each wheel cylinder based on a command from a controller including a one-chip type microcomputer or the like. Although the brake fluid pressure for the wheel cylinders on the rear side is reduced compared to that on the front side, the control form for each wheel may differ, but the proportional solenoid valve 60 is configured for each channel. Are the same. The proportional solenoid valve 60 is provided with a spool 62 in a hole inside a housing 61, a small piston 63 is applied to one end of the spool 62, and a force from a moving member 64 of an electromagnetic drive unit is applied to the other end of the spool 62. It is like this.

A reaction force due to the hydraulic pressure supplied to the wheel cylinder through the proportional solenoid valve 60 acts on the small piston 63, while the moving member 64 is applied to the solenoid 65 by a command from the controller. Excitation force based on the excitation current is used. The proportional solenoid valve 60 responds to the reaction force and the exciting force of the spool 62 facing each other and moves in the axial direction, thereby opening and closing the pump unit 50 and the reservoir 11 and between the pump unit 50 and the wheel cylinder. Open and close. Since the excitation current in the solenoid 65 of the proportional solenoid valve 60 and the pressure on the wheel cylinder side are in a proportional relationship, the controller calculates the hydraulic pressure value to obtain the required break torque and sends the command to the proportional solenoid valve 60. By giving it, the required brake fluid pressure can be controlled. In addition, the brake fluid pressure supplied to each wheel cylinder from the outlet 66 of the proportional solenoid valve 60 is detected by a fluid pressure sensor, and whether the output fluid pressure of the proportional solenoid valve 60 is in accordance with the controller's command or not It is also possible to monitor whether or not there is, and further, to detect the brake torque acting on the wheel with a torque sensor, and to correct the hydraulic pressure value to be controlled according to the variation in the friction coefficient of the braking device.

A switching valve device 100 having a function of selecting two pressure generation sources is provided between the master cylinder 10 and each wheel cylinder, and between each proportional solenoid valve 60 and each wheel cylinder. It is provided for each channel. FIG. 2 is an enlarged sectional view showing the switching valve device 100. Next, the switching valve device 100 will be described with reference to FIG. The switching valve device 100 includes a horizontally long housing 110. The housing 110 has a cylinder hole 120 in which a small-diameter hole 121 and a large-diameter hole 122 are continuous with each other through a step portion 123 with their axes aligned. The housing 110 is also connected to the end of the large diameter hole 122 at the first inlet 201 communicating with the master cylinder 10 and at the end of the opposite small diameter hole 121 at the outlet 66 side of the proportional solenoid valve 60. And a second inlet 202. Further, the housing 110 is provided with a first outlet 301 in a portion of the small diameter hole 121, a second outlet 302 in a portion of the large diameter hole 122, and a vent port 350 that communicates with the atmosphere in a portion of the step portion 123. The first and second outlets 301 and 302 are supply ports to the wheel cylinder.

On the other hand, a stepped piston 500 is movably accommodated in the cylinder hole 120 inside the housing 110. The piston 500 includes a small diameter portion 510 that fits the small diameter hole 121 and a large diameter portion 520 that fits the large diameter hole 122. The piston 500 includes O-rings 610 and 620 on the outer circumferences of the small diameter portion 510 and the large diameter portion 520, respectively, and valve portions 711 and 712 at the ends of the large and small diameter portions 520 and 510, respectively. These valve portions 711 and 712 are configured such that the ring members 711a and 712a attached to the respective ends of the piston 500 serve as valve bodies, and the bottom walls 711b and 712b of the cylinder holes 120 serve as valve seats. The valve portion 711 functions to open and close the communication between the second inlet 202 and the inside of the large diameter hole 122, and the valve portion 712 functions to open and close the communication between the first inlet 201 and the inside of the small diameter hole 121.

The piston 500 opposes the pressure from the master cylinder 10 side and the pressure from the proportional solenoid valve 60 side to both ends of the piston 500, and the two valve portions 711 and 711 are set in accordance with the difference in acting force between the two pressures. One of 712 is opened and the other is closed. For normal brake operation, the piston 500 is at the position shown in the figure, and the valve portion 711 on the small diameter portion 510 side is closed. Therefore, at that time, the pressure from the master cylinder 10 is supplied to the wheel cylinder side from the first inlet 201 of the switching valve device 100 through the second outlet 302. However, when various automatic brakes such as anti-skid, follow-up running or cornering running are activated, the piston 500 moves so as to close the valve portion 712 on the opposite side and open the valve portion 711. Therefore, in that case, the controlled brake fluid pressure from the proportional solenoid valve 60 side is supplied to the wheel cylinder side from the second inlet 202 through the first outlet 301.

The switching valve device 100 of the present invention prevents the communication between the first inlet 201 side and the second inlet 202 side during the movement of the piston 500, so that the outer peripheral portion of the piston 500 is prevented. Auxiliary valve portions 811 and 812 are provided. Each of the auxiliary valve portions 811 and 812 is a spool type valve having the piston 500 as a valve body and the first and second outlets 301 and 302 as valve ports. It is composed of a part 302. In order to have the function of “blocking the communication between the first inlet 201 and the second inlet 202 during the movement of the piston 500”, the distance between A and B is equal to the distance between C and D. It is set equal or larger. Here, point A is a step on the outer circumference of the small diameter portion 510, point B is the position showing the end wall of the first outlet 301, and point C is the tip of the ring member 712a of the large diameter portion 520. Point D is the position showing the bottom wall 712b of the cylinder hole 120 where the tip of the ring member 712a is seated.

In addition, it is preferable that the switching valve device 100 and the proportional solenoid valve 60 are integrally provided as a valve unit integrally so that the pump unit 50 is unitized as a pump device.

[0016]

[Effect of device]

 In this invention, since the auxiliary valve portions 811 and 812 are provided around the piston 500, even if the pair of valve portions 711 and 712 are simultaneously opened during the movement of the piston 500, the two inlets 201 and 202 are connected to each other. It is possible to effectively prevent pressure leakage. Therefore, there is no delay in the rise of pressure on the outlet side due to pressure leakage, and it is very useful as a brake switching valve device for switching between different pressure sources.

[Brief description of drawings]

FIG. 1 is a brake piping diagram showing an example of a brake system including a switching valve device of the present invention.

FIG. 2 is a sectional view showing an embodiment of the switching valve device of the present invention.

[Explanation of symbols]

 10 Master Cylinder 120 Cylinder Hole (First Hole) 201 First Inlet 202 Second Inlet 301,302 Outlet 50 Pump Unit 60 Proportional Solenoid Valve 500 Piston 711,712 Valve 811,812 Auxiliary Valve

Claims (2)

[Scope of utility model registration request] 1. A first inlet connected to a master cylinder, a second inlet connected to a pressure source different from the master cylinder, an outlet connected to a wheel cylinder, and this outlet, and A hole communicating with the first and second inlets, and a pair of valve portions capable of opening and closing the communication between the first inlet and the outlet and the communication between the second inlet and the outlet. And disposed in the hole to receive the first inlet side pressure and the second inlet side pressure in opposition to each other,
Reciprocating between a first position for closing one of the pair of valve parts and opening the other, and a second position for opening one valve part and closing the other valve part in accordance with the difference in acting force due to the two pressures. A switching valve device for a brake, comprising: a piston; and the first piston when the piston is in the middle of both the first and second positions.
Switching valve device for a brake provided with an auxiliary valve portion for blocking communication between the inlet of the second inlet and the second inlet. 2. The brake switching valve device according to claim 1, wherein the auxiliary valve portion comprises a spool-shaped valve configured around the piston with the piston as a valve body.