JPH0519601Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pressure control valve having two control pressure ports.

(Prior art) As a conventional pressure control valve, for example, the Uchidarex Ross Direct Type Electromagnetic Proportional Switching Valve Catalog (May 1985, published by Silver Design Co., Ltd.)
Those described in are known.

This conventional pressure control valve includes a valve body having a valve hole in which a hydraulic pressure introduction hole, a drain hole, a first control pressure port, and a second control pressure port are formed, and a valve body that is slidably installed in the valve hole of the valve body. A valve spool is formed with a land that proportionally guides the hydraulic pressure introduced into the hydraulic pressure introduction hole to a first control pressure port and a second control pressure port, and the valve spool has both ends elastically arranged in the sliding direction. a supporting spring; a first solenoid that slides the valve spool in a pressure increasing direction of the first control pressure port in accordance with electromagnetic force; and a second solenoid.
A second solenoid that slides the control pressure port in the pressure increasing direction.

Therefore, by changing the current flowing through both solenoids, the stroke amount of the valve spool is controlled by the electromagnetic force of the solenoid and the elastic force of the spring, and by controlling the stroke amount, the first control pressure port and the second control pressure port are controlled.
The hydraulic pressure was controlled in inverse proportion to the control pressure port.

(Problem to be solved by the invention) By the way, in the above-mentioned pressure control valve, the hydraulic pressure of both control pressure ports is controlled inversely proportionally by the stroke amount of the valve spool.
This control hydraulic pressure changes in a quadratic curve with respect to the stroke amount, as shown in FIG. This is because the area of the hydraulic pressure introduction side and the side area of the hydraulic drain simultaneously change at the constricted portion between the land and the port in response to changes in the stroke amount of the valve spool, and the pressure is determined by this area change.

Therefore, the change in the control hydraulic pressure with respect to the electromagnetic force (control current or voltage) of the solenoid also becomes a quadratic curve change, and by extension, the movement of the actuator driven by the hydraulic pressure also becomes quadratic.

With conventional pressure control valves, control is difficult because the control fluid pressure and actuator change secondary to the electromagnetic force of the solenoid. In particular, as shown in Figure 4, the control of the valve spool is difficult. There was a problem in that the pressure change became large near the control pressure port's fully closed position, where the stroke amount became large, making it difficult to control in this area.

The present invention focuses on the above-mentioned conventional problems and makes control easy, prevents malfunction of the pilot piston from occurring, and improves ease of assembly and design freedom of the filter. The purpose of this invention is to provide a pressure control valve that can

(Means for Solving the Problem) In order to achieve the above-mentioned object, the pressure control valve of the present invention has a first control pressure port, a second control pressure port, a hydraulic pressure introduction hole, and a drain hole. a valve body having a valve hole, and a valve body slidably provided in the valve hole, and guiding the hydraulic pressure introduced into the hydraulic pressure introduction hole to a first control pressure port and a second control pressure port in an inverse proportion. a valve spool in which a land is formed; and a first solenoid, which is provided on the valve body at both ends of the valve spool and is pressed by a plunger in response to an electromagnetic force to slide the valve spool in the pressure increasing direction of the first control pressure port; , second
a second solenoid for sliding the control pressure port in the pressure increasing direction; and a second solenoid formed at one end of the valve spool;
A first piston hole is formed in the other end of the valve spool, and a first pilot piston is slidably inserted into the first pilot piston hole, which is provided in contact with the plunger of the second solenoid. a second piston hole into which a second pilot piston is slidably inserted; and a first feedback hydraulic hole formed so that hydraulic pressure of a first control pressure port can be introduced into the first piston hole. and a second feedback hydraulic hole formed to be able to introduce the hydraulic pressure of the second control pressure port into the second piston hole; A detailed filter is provided for each.

(Function) In the pressure control valve of the present invention, the hydraulic pressures of both control pressure ports are maintained equal in the neutral state.

From this neutral state, when the electromagnetic force of either of the solenoids is increased and the plunger pushes the valve spool, the valve spool slides from the neutral position and the control fluid pressure of one of the control pressure ports is increased. At the same time, the feedback control hydraulic pressure acts on the valve spool, and the valve spool is placed in a position where the electromagnetic force of the solenoid and the feedback hydraulic pressure are balanced, thereby increasing the control hydraulic pressure of one control pressure port. At the same time, the control hydraulic pressure of the other control pressure port is also determined in inverse proportion to this.

That is, to explain the case where the electromagnetic force of the first solenoid is increased, when the electromagnetic force of the first solenoid is increased, the valve spool slides and the control fluid pressure of the first control pressure port is increased. Control hydraulic pressure is transmitted to the first piston bore through the first feedback hydraulic bore.

Due to this increase in hydraulic pressure in the first piston hole, the first pilot piston moves in the direction of protrusion from the valve spool.
That is, the valve spool slides in a direction that presses the plunger of the second solenoid opposite to the first solenoid, and at the same time, the reaction force acts to push the valve spool back toward the first solenoid.

Therefore, the valve spool is arranged at a position where the electromagnetic force of the first solenoid and the control hydraulic pressure (feedback hydraulic pressure) received by the first piston hole are balanced, so that the hydraulic pressure of the first control pressure port is adjusted. is determined, and at the same time the hydraulic pressure of the second control pressure port is determined inversely proportional thereto.

Further, when the second solenoid is driven, it is arranged at a position where its electromagnetic force and the control hydraulic pressure received by the second piston hole are balanced, and the control hydraulic pressure of the second control pressure port is determined.

Therefore, the hydraulic pressure of both control pressure ports is determined by the balance between the electromagnetic force of both solenoids and the feedback pressure of both solenoids, regardless of the stroke amount of the valve spool, and thereby the electromagnetic force characteristics of both solenoids As a result, if the electromagnetic force change of both solenoids is linear, the characteristics of the control hydraulic pressure can be made linear, and the actuator driven by the control hydraulic pressure can be The movement of can be primarily controlled.

Furthermore, since control hydraulic pressure is applied to both piston holes, a slight leak occurs in the minute gap between the sliding portions of the pilot piston. Therefore, in both feedback hydraulic pressure holes, a small amount of hydraulic fluid flows from both control pressure ports to both piston holes, and is filtered by a filter provided therein to remove minute foreign matter contained in the hydraulic fluid.

Therefore, foreign matter does not enter the minute gap between the sliding portions of both pilot pistons, and the foreign matter does not cause malfunction of both pilot pistons. Incidentally, since the leakage from both piston holes occurs through extremely small gaps, the flow rate is small, and even if the density of the filter is increased, there is almost no pressure loss and there is no effect on the operation.

Furthermore, since this filter was inserted in the direction perpendicular to the axis of both piston holes and provided in both feedback hydraulic pressure holes, the filter prevents the hydraulic fluid from flowing between the feedback fluid path and the piston hole. It does not move in the insertion direction due to fluid pressure.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be explained.

The pressure control valve A according to an embodiment of the present invention is applied to a vehicle steering angle control device B shown in the overall system diagram of FIG. C
This is what drives the.

The hydraulic steering device C is installed on the rear wheels 2 of a car, and steers the rear wheels 2 together with the front wheels 3 in response to steering by the driver. Right steering room 4 for steering to the right
and a left steering room 5 that similarly steers the vehicle to the left. Further, in the figure, reference numeral 6 denotes an input sensor for detecting various states necessary for steering to the microcomputer 1. Further, F is a recovery filter that removes foreign matter contained in the working fluid when it is recovered into the tank T.

FIG. 1 is a sectional view showing the pressure control valve A of the embodiment, and as shown in this figure, the pressure control valve A
The main components include a valve body 10, a valve spool 20, a first solenoid 30, and a second solenoid 40.

A valve hole 61 is bored in the valve body 10, and a hydraulic pressure introduction hole 62,
First drain hole 63, second drain hole 64, first
A control pressure port 65 and a second control pressure port 66 are formed.

The hydraulic pressure introduction hole 62 is formed approximately in the center of the valve hole 61, and is supplied with hydraulic pressure from the pump P via the pressure supply path 52.

Both drain holes 63 and 64 are formed at both end positions of the valve hole 61, respectively, and are connected to the communication path 6.
7, and releases hydraulic pressure to the tank T side via the drain liquid path 53.

The first control pressure port 65 is provided at a position between the first drain hole 63 and the hydraulic pressure introduction hole 62, and is connected to the right steering room 4 of the hydraulic steering device C via the first control hydraulic pressure path 54. It is communicated.

The second control pressure port 66 is provided at a position between the second drain hole 64 and the hydraulic pressure introduction hole 62, and is connected to the left steering chamber 5 of the hydraulic steering device C via the second control hydraulic pressure path 55. It is communicated.

The valve spool 20 is slidably provided in the valve hole 61 with a certain gap relative to its inner diameter, and both ends are fitted with coil springs 21, 2.
The valve spool 20 includes a first land 23 which is provided in an underlap state at the first control pressure port 65.
A second land 24 provided in an underlapping state at the second control pressure port 66 and end lands 25 and 26 at both ends are formed, and the hydraulic pressure introduction hole 62
The hydraulic pressure introduced into the first control pressure port 65 and the second control pressure port 66 is inversely proportional to the first control pressure port 65 and the second control pressure port 66.

That is, when the valve spool 20 slides to the right from the neutral state shown in FIG. On the other hand, in the second control pressure port 66, the fluid pressure introduction side constriction section 242 narrows and the drain side constriction section 241 widens, thereby reducing the pressure.

Also, if it slides in the opposite direction, the first control pressure port 6
5 is reduced in pressure, and the second control pressure port 66 is increased in pressure.

In the valve body 10, back chambers 56, 56 are provided at both ends of the valve spool 20, and the back chambers 56, 56 communicate with the drain liquid path 53, respectively.

Also, a first piston hole 7 is provided at both ends of the valve spool 20 coaxially with the valve spool 20.
0 and a second piston hole 80 are formed.

The first piston hole 70 (right end in the figure) is
The first feedback hydraulic pressure hole 72 opened to the first control pressure port 65 allows the first control pressure port 6
5, and the first pilot piston 7
1 is slidably provided.

Similarly, the second piston hole 80 (left end in the figure) is communicated with the second control pressure port 66 through a second feedback hydraulic hole 82 opened to the second control pressure port 66, and A second pilot piston 81 is slidably provided.

Incidentally, stopper flanges 711, 811 are provided at the tips of both pilot pistons 71, 81 to restrict sliding in the recessed direction with respect to the valve spool 20.

In addition, both feedback hydraulic holes 72 and 82 are
At both lands 23 and 24, the valve spool 2
orthogonal holes 72a, 82a bored in a direction orthogonal to the axial direction of the piston holes 70, 80;
It consists of parallel holes 72b, 82b bored in the axial direction of the valve spool 20, and filters 73, 83 are provided at the connecting positions of the orthogonal holes 72a, 82a and the parallel holes 72b, 82b, respectively. ing.

The filters 73, 83 have a cylindrical shape,
It is inserted from the open ends of the orthogonal holes 72b, 82b, and is tightly fitted to filter the hydraulic fluid flowing through both the feedback hydraulic pressure holes 72, 82 to remove foreign matter. A particularly dense material is used to remove extremely minute foreign matter that may get into the minute gap between the sliding parts of both pilot pistons 71 and 82.

Note that the filters 73 and 83 are not tightly fitted, but inserted into the orthogonal holes 72a and 82a.
A stopper may be provided to fix it.

Furthermore, at both ends of this valve spool 20,
A retainer 90 is provided in a loosely fitted manner to both ends of the valve spool 20 and in contact with the end lands 25 and 26 to prevent the retainer from sliding toward the center with respect to the valve spool 20.

Further, a flange 91 is formed on this retainer 90. That is, the surface of this flange 91 serves as a seating surface for the coil springs 21 and 22, and uses the biasing force as a preload to load the valve spool 20.
Also, the valve spool 20 is connected to the retainer 9
If it slides away from 0, the flange 9
1 comes into contact with a position around the edge of the valve hole 61 to restrict movement.

A first solenoid 30 (left side in the figure) and a second solenoid 40 (right side in the figure) are provided at both ends of the valve spool 20.
0 is pressed by these plungers 31, 41 via both pilot pistons 71, 81 and slides.

The electromagnetic force of both solenoids 30 and 40 is controlled by control currents i1 and i2 from the microcomputer 1, and these control currents i1 and i2
The electromagnetic force characteristics are linear.

Also, the plunger 3 of both solenoids 30 and 40
1 and 41 slide within the range regulated by the protruding side stopper surfaces 32 and 42 and the retracting side stopper surfaces 33 and 43, and plunger springs 34 and 44
Elastically supported.

In addition, 101 and 102 in the figure are O-rings.

Next, the operation of the embodiment will be explained.

(a) When in neutral, normally the valve spool 20 is the coil spring 2
It is held at the neutral position with a constant preload applied by the biasing forces 1 and 22, and the high operating hydraulic pressure led from the hydraulic pressure introduction hole 62 is applied to both the hydraulic pressure introduction side throttle parts 232 and 242. The water passes through the drain holes 63 and 64, respectively, and returns to the tank T through the drain liquid path 53.

As a result, the hydraulic pressures of both control pressure ports 65 and 66 are kept equal, and even in the hydraulic steering device C, the hydraulic pressures of both steering chambers 4 and 5 are equal, and the rear wheel 2 maintains the straight-ahead state.

(b) When driving the first solenoid When the control current i1 from the microcomputer 1 is increased, the plunger 31 pushes the end face of the second pilot piston 81 against the preload of the coil spring 21, and the valve spool 20 As shown in the figure, the first solenoid slides toward the second solenoid 40 side (right side in the figure), closes the drain side constriction part 231 of the first land 23 and the hydraulic pressure introduction side constriction part 242 of the second land 24, and the first The hydraulic pressure in the control pressure port 65 increases.

This pressure increase in the first control pressure port 65 is transmitted to the first piston hole 70 via the first feedback hydraulic pressure hole 72, and this increased hydraulic pressure acts to cause the first pilot piston 71 to protrude from the valve spool 20. do.

When the plunger 41 of the second solenoid 40 is retracted by sliding of the first pilot piston 71 until it is regulated by the retraction side stopper 43, the reaction force of the force pressing the first pilot piston 71, that is, the feedback pressure Fp acts on the valve spool 20, and the valve spool 20
It is pushed back to the solenoid 30 side.

As a result, as shown in FIG. 2, the electromagnetic force Fsol of the first solenoid 30 and the feedback pressure Fp acting on the valve spool 20, as well as the spring force Fkl of the plunger spring 34 and the coil spring 2
1 spring force FK2 is balanced (Fsol + Fk1 = Fp
The valve spool 20 is maintained at the position (+FK2), and the pressure of the first control pressure port 65 is maintained at a predetermined pressure based on the control current i1 from the microcomputer 1.

The relationship between the electromagnetic force FSOL of the first solenoid 30 and the feedback pressure Fp is a linear proportional relationship as shown by the equation Fp=FSOL+Fk1-FK2. Further, it is desirable that the coil spring 21 and the plunger spring 34 have the same spring constant initial setting force.

By increasing the hydraulic pressure and maintaining the hydraulic pressure in the first control pressure port 65 described above, the hydraulic steering device C
Then, the hydraulic pressure in the right steering room 4 is increased, and the rear wheels 2 are operated to maintain the right steering state at a predetermined angle.

(c) When driving the second solenoid In the same way as when driving the first solenoid 30, the plunger 41 protrudes due to the increase in the control current i2 from the microcomputer 1 to the second solenoid 40, and the valve spool 20
0 side, thereby opening the drain side throttle part 231 and the hydraulic pressure introduction side throttle part 242,
The hydraulic pressure in the second control pressure port 66 is increased. This increase in hydraulic pressure causes the second pilot piston 81 to slide, and the valve spool 20 is maintained at a position where the feedback pressure based on the reaction force and the electromagnetic force of the second solenoid 40 are balanced, and as a result, the hydraulic steering device At C, the hydraulic pressure in the left steering room 5 is increased and the rear wheels 2 are operated to maintain the left steering state at a predetermined angle.

The pilot pistons 71 and 81 are pressed by either of the plungers 31 and 41 when the hydraulic pressure in the piston holes 70 and 80 decreases, causing the stopper flanges 711 and 811 to move toward the valve spool 2.
It is immersed and slid until it touches 0.

In addition, since hydraulic pressure is applied to both piston holes 70 and 80 as described above, leakage occurs to both back chambers 56 and 57 through the minute gap between the sliding parts of both pilot pistons 71 and 81. is occurring. This leak causes both feedback hydraulic pressure holes 72, 82
When the hydraulic fluid flows, foreign matter that may enter the minute gap is removed by filters 73 and 83.

By the way, in the case of these filters 73, 83, since the hydraulic pressure received at both ends is the same, the filters 73, 83 are moved in the insertion direction by the hydraulic pressure of both control pressure ports 65, 66. Furthermore, since the fluid pressure that the filters 73 and 83 receive due to the flow of the working fluid due to the leak is received in the shear direction, this also causes the filter 7
3 and 83 will not shift in the insertion direction.

Incidentally, such leakage from both piston holes 70 and 80 is extremely small, and even if the density of the filter is increased, there is almost no pressure loss and there is no effect on operation. In addition, both pilot pistons 71, 81
is pressed by either of the plungers 31, 41 when the hydraulic pressure in both the piston holes 70, 80 decreases, and is retracted and slid until the stopper flanges 711, 811 come into contact with the valve spool 20.

As described above, the hydraulic pressure of both control pressure ports 65 and 66 is determined by the balance between the electromagnetic force of both solenoids 30 and 40 and the feedback pressure received by both feedback surfaces 75 and 85, regardless of the stroke amount of the valve spool 20. Since the control currents i1 and i are determined by
2, the electromagnetic force of both solenoids 30 and 40 is 1
Since it changes sequentially, the characteristics of the control hydraulic pressure with respect to the control currents i1 and i2 can be made primary, and the operation of the hydraulic steering device C driven by the control hydraulic pressure can also be controlled primarily. .

As explained above, this embodiment has the following features.

Since the hydraulic pressure of both control pressure ports 65, 66 and the operation of the hydraulic steering device C operated by this hydraulic pressure can be primarily controlled with respect to the control currents i1, i2, highly accurate control can be easily performed. It can be carried out.

Both control pressure ports 65, 66 and both piston holes 7
Both feedback hydraulic pressure holes 7 communicating with 0 and 80
2 and 73 are formed within the valve spool 20, it can be made more compact than when formed in the valve body 10.

Since the feedback hydraulic pressure for the valve spool 20 acts within the valve spool 20 so that the feedback hydraulic pressure is not applied from the back chambers 56 and 57 at both ends, both control pressure ports 65 and 66 and both piston holes 70 ,80
Leakage from the pump always occurs in a fixed direction, resulting in stable operation.

Both piston holes 70 for pressure feedback,
Both feedback hydraulic holes 72, 8 lead to
Since the filters 73 and 83 are installed in the pistons 2 and 2 to remove foreign matter, it is possible to avoid problems caused by foreign matter in the pilot pistons 71 and 81, which slide in minute gaps and require high precision, and also to improve the reliability of the hydraulic circuit. improves. Note that this filter is installed in a location where almost no flow rate occurs, so
Easy to downsize.

Since the filters 73 and 83 do not move due to control hydraulic pressure, fluid pressure, etc., there is no need for a structure to restrict this movement, and the structure can be simplified and costs can be reduced.

Filters 73, 83 are inserted into both piston holes 70, 8.
Since it is not provided within 0, there is no size restriction and the degree of freedom in design is improved.

Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment. However, it may also be formed on the valve body.

Further, in the embodiment, an example was shown in which the pressure control valve was applied to a steering angle control device for a vehicle, but the scope of application is not limited to this as long as the hydraulic pressure of two systems is controlled proportionally.

Further, in the embodiment, an example was shown in which the back chamber was directly connected to the drain side, but an orifice may be provided between the back chamber and the drain side.

(Effect of the invention) As explained above, in the pressure control valve of the invention, the hydraulic pressure of both control pressure ports is determined by the electromagnetic force of both solenoids and both piston holes, regardless of the stroke amount of the valve spool. Since the method is determined by the balance with the control hydraulic pressure (feedback hydraulic pressure) received by the solenoid, it is possible to control the hydraulic pressure corresponding to the electromagnetic force characteristics of both solenoids, and the characteristics of the control hydraulic pressure are made primary. In addition, it is possible to primarily control the movement of the actuator driven by the control hydraulic pressure, and the effect that control becomes easy can be obtained.

At the same time, by installing dense filters in both feedback hydraulic holes, there is no possibility that foreign objects will cause malfunctions in both pilot pistons, and in that case, the resistance of the filters will not affect operation. In addition, there is no size restriction such as having to make it the same diameter as the pilot piston, which is the case when it is installed inside the piston hole, and there is a high degree of freedom in design. It will be done.

Furthermore, since this filter is installed in a direction perpendicular to the axes of both piston holes, it does not move in the insertion direction due to the fluid pressure of the hydraulic fluid, and a stopper etc. for this purpose can be omitted, reducing costs. This has the effect of being able to achieve this.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a pressure control valve according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the operation of the embodiment control valve.
FIG. 3 is an overall diagram showing a system of an apparatus to which the embodiment control valve is applied, and FIG. 4 is a graph showing changes in control hydraulic pressure with respect to changes in conventional stroke amount. A...Pressure control valve, 10...Valve body, 2
0...Valve spool, 23...1st land, 2
4...Second land, 30...First solenoid, 4
0...Second solenoid, 61...Valve hole, 62
... Hydraulic pressure introduction hole, 63 ... First drain hole, 64
...Second drain hole, 65...First control pressure port, 66...Second control pressure port, 70...First piston hole, 71...First pilot piston, 7
2...First feedback hydraulic hole, 73...Filter, 80...Second piston hole, 81...Second pilot piston, 82...Second feedback hydraulic hole, 83...Filter.

Claims (1)

[Claims for Utility Model Registration] A valve body having a valve hole in which a first control pressure port, a second control pressure port, a hydraulic pressure introduction hole, and a drain hole are formed; The hydraulic pressure introduced into the hydraulic pressure introduction hole is transferred to the first control pressure port and the second control pressure port.
A valve spool is formed with a land that is inversely proportional to the control pressure port, and a land is provided on the valve body at both ends of the valve spool, and the valve spool is pushed by a plunger according to electromagnetic force to increase the first control pressure port. a first solenoid that slides in the pressure direction; a second solenoid that slides in the pressure increasing direction of the second control pressure port; formed at one end of the valve spool and provided in contact with the plunger of the second solenoid; a first piston hole into which a first pilot piston is slidably inserted; and a second pilot piston formed at the other end of the valve spool and in contact with the plunger of the first solenoid. a second piston hole into which the hydraulic pressure of the first control pressure port can be introduced, a first feedback hydraulic pressure hole formed so that hydraulic pressure of the first control pressure port can be introduced into the first piston hole; A second feedback hydraulic hole formed to be able to introduce the hydraulic pressure of the port; and a dense filter inserted in a direction perpendicular to the axis of both piston holes and provided in each of the feedback hydraulic holes. A pressure control valve characterized by: