JP2560676Y2 - Pressure control valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control valve for controlling a fluid pressure by sliding a spool, which is applied to an on-vehicle steering device or other industrial equipment.

[0002]

2. Description of the Related Art As a conventional pressure control valve, for example, a pressure control valve described in JP-A-63-213003 is known. The pressure control valve is slidably housed in a valve hole formed in the valve body, and adjusts a throttle amount between the hydraulic pressure supply circuit and the first and second output circuits and the drain circuit based on the slide. A spool formed so as to control the output hydraulic pressure of either the first output circuit or the second output circuit, and increasing the output hydraulic pressure of the spool in the first output circuit or the second output circuit. First and second solenoids that slide by pressing in the directions, a back chamber formed to allow sliding of the spool at both end positions of the valve hole, and a communication passage communicating between the two back chambers. It is provided with. That is, in this conventional example, the communication path allows the liquid to flow between the two back chambers, thereby coping with a change in the volume of the two back chambers caused by sliding of the spool.

[0003] Normally, a dither current is used as a control current input to the solenoid in order to reduce the sliding resistance of the spool by micro-vibration, thereby reducing the hysteresis of the control hydraulic pressure. Therefore, the output hydraulic pressure pulsates due to the vibration of the spool, but in this conventional example, the flow resistance of the liquid is increased by narrowing the cross-sectional area of the communication passage between the two back chambers. Increase the back pressure of the back chamber in the direction in which the spool slides,
The pulsation of the output hydraulic pressure can be suppressed by suppressing the vibration of the spool.

[0004]

However, in the above-mentioned prior art, since the passage cross-sectional area of the communication passage is constant, there are the following problems. That is, the sensitivity of increasing the output hydraulic pressure with respect to the stroke amount of the spool increases as the supply hydraulic pressure from the hydraulic pressure supply circuit increases, so that the passage cross-sectional area of the communication passage communicating between the two back chambers is constant. As the supply hydraulic pressure increases, the pulsation of the output hydraulic pressure also increases.

The present invention has been made in view of the above-described problem. Even if the supply hydraulic pressure fluctuates, the pressure which can suppress the pulsation of the output hydraulic pressure in accordance with the increase of the hydraulic pressure is provided. It is intended to provide a control valve.

[0006]

As means for solving the above-mentioned problems, the pressure control valve of the present invention is slidably incorporated in a valve hole formed in a valve body.
A spool formed so that the amount of throttle between the hydraulic pressure supply circuit, the output circuit, and the drain circuit is adjusted based on the sliding to control the output hydraulic pressure to the output circuit; and Pressing means for pressing and sliding in a direction, a back chamber formed to allow the spool to slide at both end positions of the valve hole, a communication passage communicating between the two back chambers, and the communication passage A variable throttle that can change the passage cross-sectional area of the communication passage is formed in the middle of the movable passage so as to be displaceable, and is displaced in a direction to reduce the throttle opening of the variable throttle by receiving the hydraulic pressure of the hydraulic pressure supply circuit. And a biasing means for biasing the movable member in a direction to increase the aperture of the variable aperture.

[0007]

For example, when the spool is minutely vibrated by using a dither current as a drive current of the pressing means, a pulsation is generated in the output hydraulic pressure. Since the movable member is displaced in the direction of reducing the aperture of the variable throttle by receiving the pressure, the flow resistance of the liquid communicating with the communication passage communicating between the two back chambers increases,
The back pressure in the back chamber in the direction in which the spool slides is increased, so that the vibration of the spool is buffered by the back pressure in both back chambers, and pulsation of the output hydraulic pressure can be suppressed.

The movable member is arranged at a position where the pressing force by the receiving pressure of the supply liquid pressure and the pressing force by the urging member are balanced. When the balance position of the movable throttle is displaced in the direction of decreasing the aperture of the variable throttle, and conversely, changes in the direction of decreasing the supply hydraulic pressure, the balance position of the movable member is displaced in the direction of increasing the aperture of the variable aperture. Will do.

Therefore, in the pressure control valve of the present invention, the automatic adjustment is performed so that the opening of the variable throttle is inversely proportional to the supply hydraulic pressure. Therefore, even if the supply hydraulic pressure fluctuates, the hydraulic pressure increases. Pulsation of the output hydraulic pressure can be suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. First, the configuration of the embodiment will be described.
FIG. 2 is a sectional view showing a pressure control valve according to an embodiment of the present invention, the pressure control valve comprising a first output circuit S1 and a second output circuit S;
The second is to selectively control the output hydraulic pressures P ₁ and P ₂ , that is, to control one of the hydraulic pressures so that the other is the drain pressure. Such control is used, for example, for the operation of the steering angle control device for the rear wheels. In the steering angle control device, the output hydraulic pressure of the first output circuit S1 and the output hydraulic pressure of the second output circuit S2 are increased. An operation in which the rear wheels are steered to the right by the pressure drop, and conversely, the rear wheels are steered to the left by the output hydraulic pressure drop of the first output circuit S1 and the output hydraulic pressure rise of the second output circuit S2. It is something that is done.

In the drawing, reference numeral 1 denotes a valve body,
The valve body 1 is provided with a valve hole 11. The first output port 1 is provided in the valve hole 11.
1a and a second output port 11b are formed.
1a and 11b, a hydraulic pressure supply port 11c connected to the hydraulic pressure supply circuit 2 is formed.
Drain ports 11d and 11e connected to the drain circuit 3 are formed outside of the drain ports a and 11b.

Further, a first back chamber 1a and a second back chamber 1b having a larger diameter than the valve hole 11 are formed at both ends of the valve hole 11. Further, a return pipe constituting the drain circuit 3 is connected to both drain ports 1 through the valve body 1.
Screw holes 13 for connecting to 1d and 11e are formed.

The first output port 11a is connected to a first output circuit S1, while the second output port 11b is connected to a second output circuit S2. The hydraulic pressure supply circuit 2 is supplied with hydraulic pressure from a pump P, while the drain circuit 3 is connected to a reservoir tank T and is at atmospheric pressure.

A communication passage 1 is provided between the two back chambers 1a and 1b.
5, and the liquids in both back chambers 1a and 1b can be mutually circulated. In the middle of the communication passage 15, a sliding hole 17 defined by the slidable piston 16 in the upper chamber A and the lower chamber B is formed. The communication passage 15 is provided so that a middle part thereof is opened, while the upper chamber A side is communicated with the hydraulic pressure supply port 11 c side by an introduction hole 18, and the supply of the hydraulic pressure supply circuit 2 to the upper surface side of the piston 16. It is in a state of receiving hydraulic pressure. A variable throttle 14 is formed between the opening of the communication passage 15 that opens to the inner peripheral surface of the lower chamber B and the outer peripheral surface of the lower end of the piston 16, and the piston 16 slides downward. , The aperture of the variable aperture 14 changes in the direction of decreasing. On the lower chamber B side, there is provided a spring 19 which presses and biases the piston 16 in a direction to raise the piston 16, that is, in a direction to increase the aperture of the variable throttle 14.

That is, when the piston 16 is disposed at a position where the downward pressing force by the supply hydraulic pressure and the upward pressing force by the spring 19 are balanced, the opening of the variable throttle 14 in inverse proportion to the supply hydraulic pressure is increased. Automatic adjustments are made to the degree.

The spool 4 is slidably housed in the valve hole 11. The spool 4 has a first land 4a which is provided in an underlap state at the first output port 11a to form a throttle between the first output port 11a and the valve hole 11;
A second land 4b which is provided in the output port 11b in an underlap state and forms a throttle between the output port 11b and the valve hole 11, and end lands 4c and 4d at both ends are formed. still,
The spool 4 has a centering spring 40 at both ends.
A and 40b are elastically supported and slidably biased to be disposed at a neutral position where both output hydraulic pressures P ₁ and P ₂ have the same hydraulic pressure. Also, centering springs 40a, 40b
Are seated on retainers 41a and 41b.

The retainer 41a, 41b has an inner end face in a state where the spool 4 is in a neutral position, and simultaneously comes into contact with both end faces of both openings of the valve hole 11 and outer end faces of both end lands 4c, 4d. When the spool 4 is in the neutral position or when the spool 4 slides away from the centering springs 40a and 40b, the elastic force is not transmitted to the spool 4.

At both ends of the spool 4, a first piston sliding hole 63a and a second piston sliding hole 63b are formed in the axial direction.
Are formed, and the piston sliding holes 63a,
A first pilot piston 64a having a cylindrical shape is provided at 63b.
And a second pilot piston 64b are slidably inserted.

The sliding of the spool 4 is performed by first and second solenoids 5a and 5b. That is, the first solenoid 5a and the second solenoid 5a are provided at both ends of the valve body 1, respectively.
A solenoid 5b is provided, and both solenoids 5a,
When the coils 52a and 52b of 5b are energized, the plungers 51a and 51b slide by the generated attraction force and press the spool 4 with the rods 53a and 53b. When the first solenoid 5a is energized, the spool 4 moves to the right in the figure. To the first output port 11a (first output circuit S1)
The output hydraulic pressure P ₁ of the second output port 1 is increased.
The output pressure P ₂ of the 1b (second output circuit S2) becomes the drain pressure, conversely, the output pressure P ₂ of the energizing the second solenoid 5b second output port 11b (second output circuit S2) is raised Rutotomoni, the output pressure P ₁ of the first output port 11a (first output circuit S1) becomes the drain pressure.

The two pilot pistons 64a,
64b and rods 53a, 53 of both solenoids 5a, 5b
b, stopper members 7a and 7b are interposed. The stopper members 7a and 7b are formed in a cylindrical shape having a bottom as shown in FIG.
The pressing forces a and 53b can be transmitted to the spool 4 and the pilot pistons 64a and 64b, and the sliding amount of the spool 4 can be regulated to a predetermined amount.

The piston sliding holes 63a and 63b are
The first feedback hydraulic pressure introduction hole 61a and the second feedback hydraulic pressure introduction hole 61b formed in the spool 4 communicate with the first output port 11a and the second output port 11b, respectively.
4b, the one end face side receives the feedback hydraulic pressure, and the spool 4 is pushed back by a reaction force due to the feedback hydraulic pressure. And the reaction force (feedback force) of this feedback hydraulic pressure,
When the spool 4 is disposed at a position where the pressing forces of the solenoids 5a and 5b are balanced, the output hydraulic pressures P ₁ and P ₂ of the output circuits S1 and S2 are reduced to a hydraulic pressure proportional to a current value supplied to the solenoids 5a and 5b. Controlled.

Next, the operation of the embodiment will be described. In the description of the embodiment, the operation for controlling the hydraulic pressures of the two output circuits S1 and S2 is well-known in the above-mentioned publication of the prior art, so that the description is omitted. The operation unique to this embodiment will be described.

When performing hydraulic control, the solenoids 5a,
5b, a dither current is used in order to remove the sliding resistance of the spool 4 and to suppress the hysteresis of the control hydraulic pressure to a small value. By vibrating, the sliding resistance is reduced, whereby the control hydraulic pressure can be controlled without hysteresis.

On the other hand, when the spool 4 vibrates minutely due to the dither current, pulsation occurs in the output hydraulic pressure. At this time, the piston 16 moves downward due to the supply hydraulic pressure introduced into the upper chamber A side. Since it is pressed and the aperture of the variable aperture 14 is reduced, the two back chambers 1a,
1b, the flow resistance of the liquid flowing through the communication passage 15 communicating between the first chamber 1b and the back chamber 1a in the direction in which the spool 4 slides is increased.
The back pressure in 1b increases. Therefore, by this back pressure,
Since the vibration of the spool 4 is buffered, pulsation of the output hydraulic pressure can be suppressed.

The piston 6 is disposed at a position where the downward pressing force of the supply hydraulic pressure and the upward pressing force of the spring 19 are balanced, so that the supply hydraulic pressure increases. If it changes, the balance position of the piston 16 moves downward and changes in the direction in which the throttle opening of the variable throttle 14 decreases, and conversely, if it changes in the direction in which the supply hydraulic pressure decreases, the balance position of the piston 16 increases. To the direction in which the aperture of the variable aperture 14 increases.

As described above, in the pressure control valve of this embodiment, the automatic adjustment is performed so that the opening of the variable throttle 14 is inversely proportional to the supply hydraulic pressure. It has the feature that pulsation of hydraulic pressure can be suppressed.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Included in the present invention. For example, in the embodiment, the case where the piston is used as the movable member has been described,
A diaphragm, bellows, or the like can be used.

Further, in the embodiment, the solenoid as the pressing means is provided at both ends of the valve body to control the hydraulic pressure of the first and second output circuits. Can also be applied to those that control. Further, in the embodiment, the solenoid is used as the pressing means, but other means can be used.

[0029]

As described above, in the pressure control valve according to the present invention, the back chamber formed to allow the sliding of the spool at both ends of the valve hole, and the back chamber between the two back chambers. And a variable throttle that can change the passage cross-sectional area of the communication passage is provided in the middle of the communication passage so as to be displaceable,
A movable member that is displaced in a direction to decrease the aperture of the variable throttle by receiving the hydraulic pressure of the hydraulic pressure supply circuit, and a biasing unit that biases the movable member in a direction to increase the aperture of the variable aperture. With the provision of the above, automatic adjustment is performed so that the opening degree of the variable throttle according to the supply hydraulic pressure is adjusted. From this, even if the supply hydraulic pressure fluctuates, it is possible to respond to the increase in the hydraulic pressure. The effect that the pulsation of the output hydraulic pressure can be suppressed is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a spool neutral state of a pressure control valve according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Valve body 1a 1st back room 1b 2nd back room 2 Hydraulic pressure supply circuit 3 Drain circuit 4 Spool 5a 1st solenoid (pressing means) 5b 2nd solenoid (pressing means) 11 Valve hole 14 Variable throttle 15 Communication path 16 Piston (movable member) 19 spring (urging means) S1 first output circuit S2 second output circuit P ₁ first output fluid pressure P ₂ second output hydraulic pressure

Claims (1)

(57) [Scope of request for utility model registration] A valve body formed in a valve body is slidably provided in a valve body, and a throttle amount between a hydraulic pressure supply circuit, an output circuit, and a drain circuit is adjusted based on the sliding to adjust the throttle amount to the output circuit. A spool formed so as to control the output hydraulic pressure, pressing means for pressing the spool in the output hydraulic pressure increasing direction and sliding, and formed to allow sliding of the spool at both end positions of the valve hole. And a communication passage communicating between the two back chambers, and a variable throttle formed in the middle of the communication passage so as to be capable of changing the cross-sectional area of the communication passage. A movable member that is displaced in a direction to decrease the aperture of the variable throttle by receiving the hydraulic pressure of the circuit; and an urging unit that urges the movable member in a direction to increase the aperture of the variable aperture. A pressure control valve, comprising: