JPH0426723Y2 - - 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 on which a land is formed to proportionally switch the hydraulic pressure introduced into the hydraulic pressure introduction hole between a first control pressure port and a second control pressure port; a supporting spring; a first solenoid that slides the valve spool in the pressure increasing direction of the first control pressure port in response to electromagnetic force; and a second solenoid that slides the valve spool in the pressure increasing direction of the second control pressure port.
It was equipped with a solenoid.

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 with the control pressure port was controlled proportionally.

(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 by the stroke amount of the valve spool, but this control hydraulic pressure is As shown in Figure 4, it changes in a quadratic curve with respect to the stroke amount. This is because the area of the hydraulic pressure inlet side and the area of the hydraulic drain side change at the same time in the constricted portion between the land and the port as the stroke amount of the valve spool changes, and the pressure is determined by this change in area.

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.

(Means for solving the problem) The present invention was made with the purpose of solving the above-mentioned problems, and in order to achieve this purpose, the first control pressure port, the second control pressure port , a valve body having a valve hole in which a hydraulic pressure introduction hole and a drain hole are formed;
A valve spool is provided with a land that is inversely proportionally switched between a control pressure port and a second control pressure port, and a land is provided on the valve body at both ends of the valve spool, and the valve spool is pressed by a plunger according to an electromagnetic force. a first solenoid that slides the control pressure port in the pressure increasing direction of the first control pressure port;
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 chamber is formed in a first piston chamber into which a first pilot piston is slidably inserted and is provided in contact with the plunger of the second solenoid, and a first piston chamber is formed at the other end of the valve spool and is in contact with the plunger of the first solenoid. a second piston chamber into which a second pilot piston is slidably inserted; and a first feedback hydraulic pressure path formed so as to be able to introduce hydraulic pressure from a first control pressure port into the first piston chamber. and a second feedback hydraulic pressure path formed to be able to introduce the hydraulic pressure of the second control pressure port into the second piston chamber, and a dense filter provided in both feedback hydraulic pressure paths. The method is characterized by

(Operation) In the pressure control valve of the present invention, 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 controls either of the control pressure ports. As the hydraulic pressure increases, 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 both control pressure ports. is determined.

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 chamber via a first feedback hydraulic path.

Due to this increase in the hydraulic pressure in the first piston chamber, 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 in the first piston chamber are balanced, thereby increasing the hydraulic pressure of the first control pressure port. It is to be determined. Further, when the second solenoid is driven, it is arranged at a position where its electromagnetic force and the control hydraulic pressure received in the second piston chamber 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 chambers, a slight leak occurs between minute gaps in the sliding portion of the pilot piston. Therefore, in both feedback hydraulic pressure paths, a small amount of hydraulic fluid flows from both control pressure ports to both piston chambers, and is filtered by a filter provided therein to remove minute foreign matter contained in the hydraulic fluid.

Therefore, no foreign matter can enter between the minute gaps between the sliding parts of both pilot pistons, and the foreign matter will not cause malfunction of both pilot pistons. In addition, since the leak from both piston chambers occurs through an extremely small gap, the flow rate is small, and even if the density of the filter is increased, there will be almost no pressure loss, and the effect on operation will be minimal. do not have.

(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.
The hydraulic steering device C is driven based on i2. Furthermore, this hydraulic steering device C
is installed on the rear wheels 2 of an automobile, and steers the rear wheels 2 together with the front wheels 3 in response to steering by the driver. Right steering steers the rear wheels 2 to the right by introducing hydraulic pressure. A room 4 and a left steering room 5 that similarly steers to the left are provided. 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 vibe spool 20, a first solenoid 30, and a second solenoid 40.

A valve hole 61 is bored in the valve body 10, and the valve hole 51 has a hydraulic pressure introduction hole 62,
A first drain hole 63, a second drain hole 64, a first 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 respectively valve holes 6
1, and a communication path 67
and releases hydraulic pressure to the tank T side via the drain liquid path 53.

The first control pressure port 65 is connected to the first drain hole 6
3 and the hydraulic pressure introduction hole 62, and communicates with the right steering chamber 4 of the hydraulic steering device C via the first control hydraulic pressure path 54.

The second control pressure port 66 is connected to the second drain hole 6
4 and the hydraulic pressure introduction hole 62, and communicates with the left steering chamber 5 of the hydraulic steering device C via the second control hydraulic pressure path 55.

The valve spool 20 is slidably provided in the valve hole 61 with a certain distance from the inner diameter of the valve hole 61, and has both ends supported by 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 guided to the first control pressure port 65 and the second control pressure port 66 are switched in inverse proportion.

That is, in the state shown in FIG. 1, when the valve spool 20 slides to the right, the area of the drain side constriction section 231 of the first control pressure port 65 narrows, and the hydraulic pressure introduction side constriction section 232 widens. On the other hand, at the second control pressure port 66, the fluid pressure introduction side constriction section 242 narrows and the drain side constriction section 24 narrows.
1 expands and the pressure is reduced. Incidentally, when sliding in the opposite direction, the pressure in the first control pressure port 65 is reduced and the pressure in the second control pressure port 66 is increased. In addition, valve body 10
Back chambers 56, 56 are provided at both ends of the valve spool 20, and the back chambers 56, 5
6 are connected to the drain liquid path 53, respectively.

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

A first pilot piston 71 is slidably provided in the first piston chamber 70 (right end in the figure), and is communicated with the first control pressure port 65 through a first feedback hydraulic pressure path 72. .

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

Further, piston chamber filters 73 and 83 are provided in both feedback hydraulic pressure passages 72 and 82, respectively, to filter the hydraulic fluid flowing through both feedback hydraulic pressure passages 72 and 82 to remove foreign matter. These piston chamber filters 73, 83 are made of particularly dense material, and are able to remove extremely fine foreign matter that may get into the tiny gaps between the sliding parts of both pilot pistons 71, 82. ing.

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.

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 forces of both solenoids 30 and 40 are controlled by control currents i1 and i2 from the microcomputer 1, and the electromagnetic force characteristics with respect to these control currents i1 and i2 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 drain side throttle part 231 of the first land 23 and the hydraulic pressure introduction side throttle part 24 of the second land 24 slide toward the second solenoid 40 side (right side in the figure).
2 is closed, and the hydraulic pressure of the first control pressure port 65 increases.

This pressure increase in the first control pressure port 65 is transmitted to the first piston chamber 70 via the first feedback hydraulic pressure path 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.
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
is slid to the side, thereby causing the drain side constriction part 2
31 and the hydraulic pressure introduction side throttle part 242 are opened, and the second
The hydraulic pressure in the 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 chambers 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 the piston chambers 70 and 80 as described above, it passes through the small gap between the sliding parts of both the pilot pistons 71 and 81 to the two back chambers 56 and 57. A leak has occurred. This leak causes both feedback hydraulic pressure passages 72, 82
When the hydraulic fluid flows through the piston chamber filters 73 and 8, foreign matter that may get into the minute gap is removed.
It is removed by 3.

Incidentally, such leakage from both the piston chambers 70, 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 the 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 chambers 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 it is determined by Therefore, 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 primarily controlled.

As explained above, this embodiment has the following features.

Both control pressure ports 6 for control currents i1 and i2
Since the hydraulic pressures 5 and 66 and the operation of the hydraulic steering device C operated by the hydraulic pressures can be primarily controlled, highly accurate control can be easily performed.

Both control pressure ports 65, 66 and both piston chambers 7
Both feedback hydraulic pressure paths 7 that communicate 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.

double piston chamber 70 for pressure feedback;
Both feedback hydraulic lines 72, 8 lead to
Since piston chamber filters 73 and 83 are installed in piston chamber filters 73 and 83 to remove foreign matter, both pilot pistons 7 slide in minute gaps and require high precision.
Trouble caused by foreign matter in Nos. 1 and 81 can be avoided, and the reliability of the hydraulic circuit is improved. Note that since this filter is provided at a location where almost no flow rate occurs, it is easy to downsize.

Since the feedback hydraulic pressure for the valve spool 20 acts within the valve spool 20 and prevents the feedback hydraulic pressure from being applied from the back chambers 56 and 57 at both ends, both control pressure ports 65 and 66 and both piston chambers 70 ,80
Leakage from the pump always occurs in a fixed direction, resulting in stable operation.

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 chambers, 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, since dense filters are installed in both feedback hydraulic pressure paths, there is no possibility that foreign matter will cause malfunctions in both pilot pistons, and in that case, the resistance of the filters will not affect operation. Effects can be obtained.

[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, 6
6... Second control pressure port, 70... First piston chamber, 71... First pilot piston, 72...
1st feedback hydraulic pressure path, 73...Piston chamber filter, 80...2nd piston chamber, 81...2nd pilot piston, 82...2nd feedback hydraulic pressure path, 83...Piston chamber 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 in which a land is formed to switch inversely proportionally to a control pressure port; and a valve body provided on each end side of the valve spool, and pressed by a plunger according to electromagnetic force to switch the valve spool to the first control pressure port. a first solenoid that slides in the pressure increasing direction; a second solenoid that slides in the pressure increasing direction of the second control pressure port; A first piston chamber 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 are slidably inserted into the first piston chamber. a second piston chamber movably inserted therein; a first feedback hydraulic pressure path formed to be able to introduce hydraulic pressure from a first control pressure port into the first piston chamber; and a second control pressure passage into the second piston chamber. A pressure control valve comprising: a second feedback hydraulic pressure path formed to be able to introduce hydraulic pressure from a pressure port; and a dense filter provided in both feedback hydraulic pressure paths.