JPH05270378A - Pressure control device - Google Patents

Abstract

PURPOSE:To perform regulation of a pressure always in a proper way without leakage of liquid to a reservoir, in a pressure control device which regulates a liquid pressure through alternate communication between a liquid pressure source and a reservoir. CONSTITUTION:Pistons 31 and 33 are slidably contained in a liquidtight state in a cylinder 33a and a first liquid pressure chamber 34 communicated to an accumulator 9 through a valve body 38, a second liquid pressure chamber 35 between pistons 31 and 32, and a third liquid chamber 36 communicated to a reservoir 14 are formed. Pistons 31 and 32 are driven in a way that the volume of the second liquid pressure chamber 35 is regulated through forward and backward movement of a plunger 39p according to excitation and non- excitation of a solenoid 39s, and a liquid pressure outputted from an output port 33c is regulated to a given value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control device,
In particular, it relates to a pressure control device applied to a brake fluid pressure control device for a vehicle.

[0002]

2. Description of the Related Art In a vehicle brake fluid pressure control device, a pressure control device for adjusting the brake fluid pressure is provided in order to perform anti-skid control, traction control, etc., or to improve braking performance. As such a pressure control device, for example, in Japanese Unexamined Patent Publication No. 3-90462, a differential pressure is generated before and after an orifice in a movable spool each time a step-up / down is performed, and this differential pressure is balanced with the output of an electric / force converter. A hydraulic pressure control device has been proposed in which the step-up / down speed automatically corresponds to the electric command.

[0003]

However, in the above-mentioned conventional apparatus, the pressure is controlled by sliding the spool. For this reason, fluid leaks from the outer circumference of the spool to the reservoir, and the accumulator pressure, which is the output fluid pressure of the fluid pressure source, decreases even when the brake pedal is not operated, and the operating noise of the pump frequently occurs, and the driver Will be uncomfortable with. As a countermeasure against this, it is conceivable to reduce the clearance of the spool, but if this is done, the sliding resistance becomes large, so the driving force of the solenoid must be made large, and the size becomes large.

Therefore, in the present invention, in a pressure control device which regulates the fluid pressure by alternately communicating with the fluid pressure source and the reservoir, it is possible to always properly perform the pressure regulation without leaking the fluid to the reservoir. The purpose is to do.

[0005]

In order to achieve the above object, the present invention is interposed between a hydraulic pressure source and a reservoir, and the output hydraulic pressure of the hydraulic pressure source is input from an input port and output from the output port. In a pressure control device that controls a hydraulic pressure of a predetermined value by switching at least two positions of a position for outputting and a position for communicating the output port with the reservoir through a drain port, a housing that forms a cylinder, A first piston and a second piston that are slidably and liquid-tightly accommodated in the cylinder.
A piston; a first hydraulic chamber defined between the housing and one axial end surface of the first piston in the cylinder; and the first piston and the second piston in the cylinder.
A second hydraulic chamber that is formed between the piston and a third hydraulic chamber that is formed between the housing and the axial end surface of the second piston in the cylinder, and is interlocked with the first piston. A valve member that connects or disconnects the first hydraulic chamber with the hydraulic pressure source via the input port, and a volume varying unit that increases or decreases the volume of the second hydraulic chamber is provided. A chamber is connected to the reservoir via the drain port, the first hydraulic chamber and the third hydraulic chamber are connected to the output port, and the volume varying means connects the second hydraulic chamber to the second hydraulic chamber. When the volume is increased, the second piston closes the drain port, and the first piston drives the valve member to communicate the first hydraulic pressure chamber with the hydraulic pressure source. When the volume of the pressure chamber is reduced, the valve member With blocking between the hydraulic chamber and said hydraulic pressure source, in which the drain port is to be opened.

In the pressure control device, the volume varying means communicates with the second hydraulic chamber, a plunger slidably accommodated in the communication passage, and the plunger in the communication passage. It is preferable to include a solenoid that is driven in a direction of approaching or separating from the second hydraulic chamber.

[0007]

In the pressure control device having the above construction, the first hydraulic chamber and the hydraulic pressure source are normally shut off by the valve member, and the third hydraulic chamber communicates with the reservoir via the drain port. .. Therefore, the output port communicates with the reservoir via the third hydraulic chamber and the drain port.

When the volume of the second hydraulic chamber is increased by the volume varying means, the first piston and the second piston move in the direction in which they are separated from each other in the cylinder. That is, the drain port is closed by the movement of the second piston, the valve member is subsequently driven according to the movement of the first piston, and the first hydraulic chamber communicates with the hydraulic pressure source via the input port. This allows
The output hydraulic pressure of the hydraulic pressure source is output from the output port via the input port, the valve member and the first hydraulic chamber. Next, when the volume of the second hydraulic chamber is reduced by the volume varying means, the first piston and the second piston move in a direction in which they approach each other.
As a result, the first hydraulic chamber and the hydraulic pressure source are disconnected from each other, and the drain port is opened, so that the output port communicates with the reservoir to reduce the pressure. Thus, the output port is switched so as to alternately communicate with the hydraulic pressure source and the reservoir according to the increase or decrease in the volume of the second hydraulic chamber by the volume changing means, and the output hydraulic pressure is adjusted by adjusting the switching frequency. Is adjusted to a predetermined value.

In the volume varying means including the plunger and the solenoid, the solenoid is normally de-energized, and the plunger is located away from the second hydraulic chamber. When the solenoid is excited, the plunger is driven toward the second hydraulic pressure chamber and the volume of the second hydraulic pressure chamber increases. Thus, the output hydraulic pressure output from the output port is adjusted to a predetermined value by repeating the excitation and non-excitation of the solenoid.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the pressure control device of the present invention will be described below with reference to the drawings. First, a brake fluid pressure control device using a pressure control device according to an embodiment of the present invention will be described. In FIG. 2, the hydraulic pressure generating device is configured to output the brake hydraulic pressure from the master cylinder 1 to the master cylinder side pipe 17 when a pedaling force is applied to the brake pedal 16. A pedaling force sensor 3 for detecting the operating force of the brake pedal 16 is provided, and a pressure sensor 2 for detecting the pressure inside the master cylinder 1 is provided.

The master cylinder 1 is connected to the simulator valve 4 via a master cylinder side pipe 17. This simulator valve is connected to the master cylinder cut valve 5 via an intermediate pipe 18, and the master cylinder cut valve 5 is connected to the wheel cylinder 8 via a pipe 19 on the wheel cylinder side.
It is connected to the. The simulator valve 4 is configured such that the volume of the simulator chamber changes in accordance with the output hydraulic pressure of the master cylinder 1 in order to give the driver a good brake operation feeling.
The applicant has separately applied for a patent for this. The master cylinder cut valve 5 is a normally open solenoid valve, which is switched and closed when excited by a signal from the electronic control unit 15. The wheel cylinder side pipe 19 is provided with a pressure sensor 41 for measuring the pressure in the wheel cylinder 8, that is, the wheel cylinder pressure.

On the other hand, as a hydraulic pressure source, a motor 13 that rotates in response to a signal from the electronic control unit 15, and this motor 1
A pump 12 that is driven by the pump 3 and that inhales the brake fluid from the reservoir 14 and boosts and outputs the brake fluid is provided.
The output hydraulic pressure 2 is stored in the accumulator 9 via the check valve 10. This accumulator pressure is detected by the pressure sensor 11 and output to the electronic control unit 15. An acceleration sensor 40 that detects the acceleration of the vehicle
Also, a wheel speed sensor 42 for detecting the rotation speed of the wheel is provided, and the detection outputs of these are also input to the electronic control unit 15.

A pressure control cut valve 6 is connected to the wheel cylinder side pipe 19, and the pressure control cut valve 6 is connected to a pressure control device 30 via a pipe line 20.
The pressure control cut valve 6 is a normally closed solenoid valve, which is switched when excited by a signal from the electronic control unit 15,
It will be open. The pressure control device 30 is switch-controlled in response to a signal from the electronic control device 15, and the pipeline 20 is selected to either the pipeline 21 connected to the accumulator 9 or the pipeline 22 connected to the reservoir 14. The hydraulic pressure in the pipe 20 is adjusted to a predetermined value.

As shown in FIG. 1, in the pressure control device 30, a housing 33 is formed with a cylinder 33a, and a first piston 31 and a second piston 32 are provided in the cylinder 33a.
Are slidably housed in a liquid-tight manner. Therefore, the first hydraulic chamber 34 is formed between the first piston 31 in the cylinder 33 a and the wall surface of the housing 33, and the second hydraulic chamber 35 is formed between the first piston 31 and the second piston 32. A third hydraulic chamber 36 is formed between the second piston 32 and the wall surface of the housing 33.

A communication passage 33f is formed on one end surface of the cylinder 33a of the housing 33, and a valve chamber 37 is formed which communicates with the cylinder 33a via the communication passage 33f. The valve seat 33 is provided at the opening of the communication passage 33f to the valve chamber 37.
g is formed. In addition, the housing 33 includes an input port 33b, an output port 33c, and a drain port 33.
d is formed, the input port 33b opens to the valve chamber 37, and the output port 33c opens to the first hydraulic chamber 34 and the third hydraulic chamber 36. The drain port 33d opens into the third hydraulic chamber 36, and a valve seat 33e is formed in the opening.

A spherical valve body 38 is housed in the valve chamber 37 and is biased by a compression spring 38s in a direction to be seated on the valve seat 33g. Therefore, the communication passage 33f is normally closed by the valve body 38. A protrusion 31a extending in the axial direction and penetrating the inside of the communication passage 33f is formed on an end surface of the first piston 31 facing the communication passage 33f, and the protrusion 31a corresponds to the compression spring when the first piston 31 slides. It is configured to push the valve body 38 against the biasing force of 38s. On the other hand, the cylinder 33a of the housing 33
A compression spring 32s is stretched between the other end surface of the second piston 32 and the second piston 32, and the second piston 32 is biased toward the first piston 31. A spherical valve element 32a is embedded in one end surface of the second piston 32 at a position where it can be seated on the valve seat 33e.

Further, the housing 33 includes a cylinder 33.
A communication passage 33h opening from the side of a to the second hydraulic chamber 35 is formed, and a plunger 39p is slidably arranged in the communication passage 33h. This plunger 39p
Is surrounded by a solenoid 39s that is excited in response to a signal from the electronic control unit 15, and is in a retracted position separated from the second hydraulic chamber 35 when the solenoid 39s is not excited. When the solenoid 39s is excited by the signal from the electronic control unit 15, the plunger 39p moves to the second hydraulic chamber 35.
The brake fluid in the second hydraulic chamber 35 is pushed away by moving forward in the direction.

The input port 33b is connected to the aforementioned conduit 21, the output port 33c is connected to the conduit 20, and the drain port 33d is connected to the conduit 22. And
The second hydraulic chamber 35 is filled with a predetermined amount of brake fluid, and the first piston 31 and the second piston 32 are always in the positional relationship shown in FIG. The compression spring 38
The biasing force of s is larger than that of the compression spring 32s, and when the volume of the second hydraulic chamber 35 increases, the second piston 32 moves before the first piston 31 and the volume of the second hydraulic chamber 35 increases. The first piston 31 is constructed so as to move first when the value decreases.

The operation of the pressure control device 30 having the above-described structure will be described. With the accumulator pressure being applied to the valve chamber 37 from the input port 33b, the solenoid 39s is excited and the plunger 39p is moved to the second hydraulic chamber 35. When sliding in the direction, the volume of the second hydraulic chamber 35 increases by the volume displaced by the plunger 39p. As a result, the second piston 32 is driven in the drain port 33d direction against the biasing force of the compression spring 32s, and the valve body 3
2a sits on the valve seat 33e. That is, the output port 33c
To the drain port 33d is closed, and communication with the reservoir 14 is cut off. Subsequently, the first piston 31 is driven in the direction of the valve body 38, and the protrusion 31a pushes the valve body 38 against the biasing force of the compression spring 38s, so that the valve body 38 separates from the valve seat 33g. , Valve chamber 3
7 and the first hydraulic chamber 34 communicate with each other through the communication passage 33f.

When the solenoid 39s is de-excited and the plunger 39p is retracted to the state shown in FIG.
The volume of the second hydraulic chamber 35 in 3a decreases, and the urging forces of the compression springs 32s and 38s move the first piston 31 and the second piston 32 in a direction in which they approach each other, so that the protrusion 31a moves out of the valve body 38. The valve body 38 is released and the valve seat 33g
And the communication passage 33f is closed. Then, valve body 3
2a is separated from the valve seat 33e, and the drain port 33d is opened. Then, the solenoid 39s is repeatedly energized and de-energized in response to a signal from the electronic control unit 15 to output an accumulator pressure from the output port 33c or to be communicated with the drain port 33d to reduce the pressure, and thus the conduit 20 The hydraulic pressure inside is adjusted to a predetermined value.

As described above, the pressure control device 30 in this embodiment is a so-called poppet type valve device having the first and second pistons 31 and 32 that are slidably and liquid-tightly accommodated in the cylinder 33a. Therefore, unlike the conventional device, liquid leakage to the reservoir 14 does not occur when the brake pedal 16 is not operated.

Next, the overall operation of the brake fluid pressure control device shown in FIG. 2 will be described. When the brake pedal 16 is not operated, the master cylinder cut valve 5 is open.
When the brake pedal 16 is operated in this state and the brake operation force is detected by the pedal effort sensor 3, the electronic control means 15 closes the master cylinder cut valve 5. After that, the force required to depress the brake pedal 16 is
It is controlled by the simulator valve 4 so as to increase according to the amount of depression of the brake pedal 16, so that a good operation feeling is obtained. At the same time, the electronic control unit 15
Controls the pressure control device 30 according to the brake operating force, where the brake fluid pressure is adjusted to a predetermined value set by the electronic control device 15 according to the brake operating force,
It is applied to the wheel cylinder 8 via the pressure control cut valve 6.

Although the above embodiment is applied to the brake fluid pressure control device equipped with the simulator valve, it is possible to provide the above embodiment device with an anti-skid control function and / or a traction control function. Further, the present invention is not limited to the above-mentioned embodiment device, and can be applied to another type of brake fluid pressure control device having these functions.

[0024]

Since the present invention is configured as described above, it has the following effects. That is, in the pressure control device of the present invention, the first fluid pressure chamber, the second fluid pressure chamber, and the third fluid pressure chamber are provided by the pistons that are slidably and liquid-tightly accommodated in the cylinder.
Since the fluid pressure chamber is defined, and the volume of the second fluid pressure chamber is increased or decreased by the volume varying means to adjust the output fluid pressure to a predetermined value, the fluid to the reservoir is not only actuated but also actuated. There is no leakage, and pressure adjustment can always be performed in a stable state. Therefore, the operating noise of the hydraulic pressure source can be minimized without increasing the size of the device.

Particularly, in the case where the volume varying means is provided with the plunger and the solenoid, the output hydraulic pressure can be adjusted to a predetermined value by repeating the excitation and the non-excitation of the solenoid, so that the control is easy. Can be formed in a small size.

[Brief description of drawings]

FIG. 1 is a sectional view of a pressure control device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a vehicle brake fluid pressure control device including a pressure control device according to an embodiment of the present invention.

3 is a cross-sectional view of a simulator valve used in the brake fluid pressure control device of FIG.

[Explanation of symbols]

 1 Master Cylinder 4 Simulator Valve 5 Master Cylinder Cut Valve 6 Pressure Control Cut Valve 8 Wheel Cylinder 9 Accumulator 12 Pump 13 Motor 14 Reservoir 15 Electronic Control Device 16 Brake Pedal 30 Pressure Control Device 31 First Piston 32 Second Piston 33 Housing 33a Cylinder 33b Input port 33c Output port 33d Drain port 33f Communication passage 33h Communication passage 34 First hydraulic chamber 35 Second hydraulic chamber 36 Third hydraulic chamber 37 Valve chamber 38 Valve body (valve member) 39p Plunger 39s Solenoid

Claims (2)

[Claims] 1. A position interposed between a hydraulic pressure source and a reservoir, wherein the output hydraulic pressure of the hydraulic pressure source is input from an input port and output from an output port, and the output port is provided via a drain port. A pressure control device for controlling a hydraulic pressure to a predetermined value by switching at least two positions communicating with a reservoir, and a first housing for housing a cylinder and a liquidtight slidable housing in the cylinder. A piston and a second piston, and a first wall that is formed between one axial end surface of the first piston in the cylinder and the housing.
Between a hydraulic chamber, a second hydraulic chamber that is defined between the first piston and the second piston in the cylinder, and an axial end surface of the second piston in the cylinder and the housing. A third hydraulic chamber, a valve member that communicates with or shuts off the first hydraulic chamber from the hydraulic source via the input port in conjunction with the first piston, and the second hydraulic chamber. A variable volume means for increasing or decreasing the volume of the chamber, the third hydraulic chamber is connected to the reservoir through the drain port, and the first hydraulic chamber and the third hydraulic chamber are output. When the volume of the second hydraulic chamber is increased by the volume varying means, the second piston closes the drain port and the first piston drives the valve member to connect the port to the port. The first hydraulic chamber communicates with the hydraulic pressure source, When the volume of the two hydraulic chambers is reduced, the valve member shuts off the first hydraulic chamber and the hydraulic pressure source, and the drain port is opened. .. 2. The volume varying means includes a communication passage communicating with the second hydraulic pressure chamber, a plunger slidably accommodated in the communication passage, and the second hydraulic pressure inside the communication passage. 2. The pressure control device according to claim 1, further comprising a solenoid that is driven in a direction of approaching or separating from the chamber.