JPH05141566A - Flow control valve - Google Patents

Abstract

PURPOSE:To easily enable the flow adjustment in a minute flow rate region, in a flow control valve. CONSTITUTION:A valve seat member 3 is provided inside a case 2, and a valve body 4 is insertedly fitted in the valve seat member 3. A compression spring 5 for energizing the valve body 4 in the valve-closing direction is provided. In addition, a pilot mechanism 7 for pressurizing a pilot chamber 37 is provided, and also a compression spring 38 for energizing the valve body 4 from the valve-closed position to a prescribed position in the valve-opening direction is provided. When the solenoid 27 of the pilot mechanism 7 is energized for pressurizing a pilot chamber 37, the valve body 4 displaces in response to this pressure, and the flow rate from a pump port 8 to a cylinder port 9 is regulated. While the displacement of the valve body 4 is between the valve-closed condition and a prescribed position therefrom, the energizing force of the compression spring 38 acts, therefore the rate in increase of the displacement of the valve body 4 to the rise in pilot pressure is small. Thus, in the beginning of valve- opening, the rate in increase of flow rate to the increase in current is small, so that the flow control in a minute flow rate region can be facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a flow control valve used in a suspension control device for controlling the attitude of an automobile.

[0002]

2. Description of the Related Art There is a suspension control device (so-called active suspension device) which automatically suppresses a change in posture of a vehicle body during traveling to improve steering stability and riding comfort of the vehicle. This active suspension system
The posture change of the vehicle body is suppressed by supplying / discharging the pressure fluid to / from the vehicle height adjusting cylinder interposed between the wheel side and the vehicle body side by using a flow control valve according to the traveling situation.

A flow control valve conventionally used in an active suspension device will be described with reference to FIG. Figure 5
As shown in FIG. 2, the flow control valve 1 has a cylindrical valve seat member 3 provided in a cylindrical case 2 having a bottom.
The valve seat member 3 constitutes a valve body. A valve body 4 is slidably fitted in the valve seat member 3. Case 2
A compression spring 5 for urging the valve body 4 in the valve closing direction is provided on the bottom side of the
Is provided. A pilot pressure mechanism 7, which will be described later, is provided on the opening side of the case 2 as a means for moving the valve body 4 by supplying pilot pressure to a pilot chamber 6 formed at one end side of the valve body 4. And the valve body 4
Is displaced in the valve opening direction against the elastic force of the compression spring 4 according to the pilot pressure generated by the pilot pressure mechanism 7.

A pump port 8 on the inlet side and a cylinder port 9 on the outlet side of the flow control valve 1 are provided on the side wall of the valve seat member 3, and these are provided on the valve body 4 side and will be described later. The oil liquid passage 10 is connected and cut off in a passage area corresponding to the displacement of the valve body 4.

The valve body 4 is formed in a cylindrical shape with a bottom, a pressure compensating valve 11 is fitted inside, and a plug 12 is fitted in the opening. The side wall of the valve body 4 is provided with a hole 13 that is in constant communication with the pump port 8 of the valve seat member 3 and a hole 14 that is in communication with the cylinder port 9 when the valve body 4 moves to the bottom side of the case 2. Are communicated with each other through a valve chamber 15 provided on the outer circumference of the pressure compensating valve 11, and the holes 13 and 14 and the valve chamber 15 form an oil liquid passage 10. The pump port 8 and the cylinder port 9 are shut off when the valve body 4 is located closest to the opening of the case 2, and are displaced toward the bottom of the case 2 to provide a passage proportional to the displacement amount. It is designed to communicate by area.

The pressure compensating valve 11 is provided with a passage 17 for communicating the valve chamber 15 with the chamber 16 on the bottom side in the valve body 4. The chamber 18 on the plug 12 side in the valve body 4 communicates with the cylinder port 9 via a hole 19 provided in the side wall of the valve body 4. Further, a compression spring 20 is interposed between the pressure compensating valve 11 and the plug 12, and urges the pressure compensating valve 11 to the bottom side of the valve body 4. The pressure compensating valve 11 transmits the pressure on the pump port 8 side to the chamber 16 via the valve chamber 15 and the passage 17, and the pressure in the chamber 18 communicating with the cylinder port 9 side in accordance with this pressure and the compression spring 20. Moves to the plug 12 side against the elastic force,
By adjusting the passage area from the pump port 8 to the valve chamber 15, regardless of the change in the pressure difference between the pump port 8 side and the cylinder port 9 side, the oil liquid from the pump port 8 side to the cylinder port 9 side can be changed. The flow rate is determined only by the position of the valve body 4.

In the pilot pressure mechanism 7, a spool 22 is slidably fitted in a sleeve 21a provided on the valve seat member 21, and one end side of the sleeve 21a communicates with the pilot chamber 6. The valve seat member 21 is provided with a pump port 23 connected to a hydraulic pressure source (not shown) and a tank port 24 connected to a reservoir tank (not shown), which are communicated with the inside of the sleeve 21a. ing. On the other hand, a valve chamber 25 is formed on the outer periphery of the spool 22. When the spool 22 is in the neutral position, the valve chamber 25 communicates with both the pump port 23 and the tank port 24, and the spool 22 is located on the pilot chamber 6 side. When moving, the valve chamber 25 communicates with the pump port 23 and is blocked from the tank port 24. When moving to the opposite side (opening side of the case 2), the valve chamber 25 communicates with the tank port 24 and from the pump port 23. It is supposed to be shut off. Further, the valve seat member 21 is provided with a passage 26 that allows the pilot chamber 6 and the valve chamber 25 to communicate with each other at all times. In addition, an electromagnetic proportional solenoid is provided in the opening of the case 2.
27 is attached, and the plunger 28 of the electromagnetic proportional solenoid 27 is in contact with the end of the spool 22. The electromagnetic proportional solenoid 27 is configured to apply a pressing force to the spool 22 that is proportional to the supplied current regardless of the stroke of the plunger 28.

The pump port 8 is connected to a hydraulic pressure source (not shown) via a passage 29, and the cylinder port 9
Is connected to a vehicle height adjusting cylinder (not shown) via a passage 30. In FIG. 5, 31 is a fixing plug for fixing the valve seat members 3 and 21 to the case 2, 32 is a bolt for attaching the electromagnetic proportional solenoid 27 to the case 2, 33, 34.
Is a drain room and 35 is a drain port.

The operation of the flow rate control valve 1 constructed as above will be described below.

The electromagnetic proportional solenoid 27 is energized and the plunger 28 is driven to move the spool 22 to the pilot chamber 6 side. Then, by disconnecting the communication from the valve chamber 25 to the pump port 23, the oil liquid in the pump port 23 flows into the pilot chamber 6 through the valve chamber 25 and the passage 26, and the pressure in the pilot chamber 6 (pilot chamber 6 Increase). When the pilot pressure rises, the spool 22 is pushed back by this pressure, so that the pilot pressure becomes stable when it balances with the pushing force of the plunger 28. Since the pressing force of the plunger 28 is proportional to the current supplied to the electromagnetic proportional solenoid 27, the pilot pressure also changes in proportion to the current.

On the other hand, when the pilot pressure rises, the valve body 4
Slides against the biasing force of the compression spring 5 and is displaced to a position where the pilot pressure and the elastic force of the compression spring 5 are balanced. As a result, the pump port 8 and the cylinder port 9 communicate with each other in a passage area corresponding to the pilot pressure. At this time, the pressure compensating valve 11 compensates the change in the pressure difference between the pump port 8 side and the cylinder port 9 side. Therefore the solenoid
Pump port 8 by adjusting the current flowing to 27
The flow rate of the oil liquid from the cylinder port 9 to the cylinder port 9 can be adjusted.

[0012]

However, in the conventional flow rate control valve 1 shown in FIG. 5, since the flow rate is proportional to the current at a constant ratio, the flow rate is adjusted in a minute flow rate region that requires fine adjustment. In this case, there is a problem that accurate adjustment is difficult because the current adjustment range is small.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a flow control valve capable of easily adjusting the flow rate in a minute flow rate range.

[0014]

SUMMARY OF THE INVENTION The present invention is directed to a valve body, a valve body slidably fitted to the valve body, a spring for urging the valve body in a valve closing direction, and a spring for the spring body. An electromagnetic proportional solenoid that acts to displace the valve element in the valve opening direction against the biasing force, and the flow rate is adjusted by displacing the valve element by the electromagnetic proportional solenoid. In the control valve, an auxiliary spring for urging the valve body in the valve opening direction from the valve closing position to a predetermined position in the valve opening direction is provided.

[0015]

With this configuration, while the valve body is displaced from the closed position to the predetermined position in the valve opening direction, the force for displacing the valve body by the electromagnetic proportional solenoid is assisted by the biasing force of the auxiliary spring. Therefore, the increase rate of the displacement amount of the spool with respect to the increase of the current supplied to the electromagnetic proportional solenoid becomes small, and the minute flow rate can be easily adjusted during this period.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The present embodiment is different from the flow control valve 1 shown in FIG. 5 only in the configuration of the pilot chamber formed at one end side of the valve body 4, and therefore the same members are given the same reference numerals and different. Only the part will be described in detail.

As shown in FIG. 1, in the flow control valve 36, a pilot chamber 37 is formed at one end side of the valve body 4 in the valve seat member 3, and the pilot chamber 37 has a valve body 4 and a pilot pressure. A compression spring 38 is interposed between the valve seat member 21 of the mechanism 7 and an auxiliary spring for urging the valve body 4 in the valve opening direction. Compression spring
The elastic force of 38 is set so that the urging force on the valve body 4 is always smaller than that of the compression spring 5 in the moving range of the valve body 4. Therefore, normally, the valve body 4 moves to the valve closing position where the spring seat 39 interposed between the compression spring 5 and the valve body 4 comes into contact with the end portion of the valve seat member 3 by the urging force of the compression spring 5. Has been done. Also, the compression spring 38
Is set such that when the valve body 4 is displaced in the valve opening direction by a predetermined amount or more, the valve body 4 has a natural length and the biasing force does not work.

The operation of the present embodiment constructed as above will be described below.

As in the conventional example shown in FIG. 1, when the electromagnetic proportional solenoid 27 is energized, a pilot pressure is generated according to the current, and this pilot pressure causes the valve body 4 to resist the urging force of the compression spring 5. Displace. At this time, when the displacement of the valve body 4 is from the closed position to a predetermined position where the valve body 4 has a natural length of the compression spring 38, that is, while the valve body 4 is biased by the compression spring 38, 4 is displaced to a position where the resultant force of the pilot pressure and the urging force of the compression spring 38 balances the elastic force of the compression spring 5. When the valve body 4 is displaced by a predetermined amount or more and the compression spring 38 has a natural length, the valve body 4 moves to a position where the pilot pressure and the elastic force of the compression spring 5 are in balance. Then, similarly to the conventional example shown in FIG. 5, the pump port 8 and the cylinder port 9 are communicated with each other in a passage area corresponding to the displacement of the valve body 4. In this way, the flow rate of the oil liquid from the pump port 8 to the cylinder port 9 can be adjusted by adjusting the current supplied to the electromagnetic proportional solenoid 27.

Next, the characteristics of the flow rate with respect to the current supplied to the solenoid 27 of the flow control valve 36 will be described with reference to FIGS.

FIG. 2 shows the valve closed state, and FIG. 3 shows the valve body 4 displaced in the valve opening direction. As shown in FIG. 2, the natural length of the compression spring 5 is L ₀ , and the set length in the closed state is
Assuming that L ₁ and the spring constant are K, the natural length of the compression spring 38 is l ₀ , the set length in the closed state is l ₁ , and the spring constant is k, the valve body 4 is displaced by x as shown in FIG. When the displacement x is (l ₀ −l ₁ ) or less, the length of the compression spring 5 is (L ₁ −x).
Since the length of the compression spring 38 is (l ₁ + x), the force F required to move the valve body 4 by the displacement x is F = K (L ₀ − (L ₁ −x)) − _{k (l 0 - (l 1} + x)) = (K + k) x + K (L 0 -L 1) -k (l 0 -l 1) ... to become. Further, when the displacement x is larger than (l ₀ −l ₁ ), the valve body 4 is separated from the compression spring 38, and therefore the force F is F = K (L ₀ − (L ₁ −x)) = Kx + K (L ₀ −L ₁ ) ... Therefore, when the displacement x is (l ₀ −l ₁ ) or less, the relationship between the force F and the displacement x is: x = F / (K + k) −K (L ₀ −L ₁ ) / (K + k) + k
(L ₀ −l ₁ ) / (K + k) ... And when the displacement x is larger than (l ₀ −l ₁ ), x = F / K− (L ₀ −L ₁ ) ...

From the equation and the force F acting on the valve body 4
And the displacement x have characteristics as shown by and in FIG. Where force F, pilot pressure P and current I
Is proportional and the displacement x and the flow rate Q are proportional, the relationship between the current I and the flow rate Q is also as shown in FIG. In addition, in FIG. 4, the broken line shows the characteristic of the conventional flow control valve.

As can be seen from FIG. 4, the flow control valve 36 is
At the beginning of opening, the rate of increase of the flow rate Q (displacement x) is small with respect to the increase of the current I (pilot pressure P), so the adjustment range of the current I is wide in the minute flow rate range, and the flow rate can be adjusted relatively easily. You can

In the above embodiment, the electromagnetic proportional solenoid 27 moves the valve body 4 by using the pilot pressure by the pilot pressure mechanism 7.
Alternatively, the valve body 4 may be moved directly at 27.

[0025]

The flow control valve of the present invention assists the force of the electromagnetic proportional solenoid to displace the valve element by the urging force of the auxiliary spring while the spool moves from the closed position to the predetermined position in the valve opening direction. Therefore, the increase rate of the displacement amount of the spool with respect to the increase of the current supplied to the electromagnetic proportional solenoid becomes small, and the minute flow rate can be easily adjusted during this period. As a result, it is possible to easily adjust the flow rate in the minute flow rate region, and it is possible to improve the adjustment accuracy, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a set state of springs when the device of FIG. 1 is closed.

FIG. 3 is an explanatory diagram showing a relationship between a displacement of a valve body and a displacement of a spring of the device of FIG.

FIG. 4 is a diagram showing a relationship between a current and a flow rate of current supplied to an electromagnetic proportional solenoid of the apparatus shown in FIG.

FIG. 5 is a vertical sectional view of a conventional flow control valve.

[Explanation of symbols]

 2 Case (valve body) 3 Valve seat member (valve body) 4 Spool 5 Compression spring 7 Pilot pressure mechanism 27 Electromagnetic proportional solenoid 38 Compression spring (auxiliary spring)

Claims (1)

[Claims] 1. A valve body, a valve body slidably fitted to the valve body, a spring for biasing the valve body in a valve closing direction, and the valve against the biasing force of the spring. An electromagnetic proportional solenoid that acts to displace the body in the valve opening direction, and a flow control valve configured to adjust the flow rate by displacing the valve body by the electromagnetic proportional solenoid, wherein the valve body is A flow control valve comprising an auxiliary spring for urging in a valve opening direction from a valve closed position to a predetermined position in a valve opening direction.