JPH07103360A - Flow amount control valve - Google Patents

Abstract

PURPOSE:To miniaturize a flow amount control valve, and improve mounting performance on a car body by providing a pilot valve, in a spool valve, for making pilot pressure flowing in/out to/from a pilot pressure chamber by a relative position of the spool valve. CONSTITUTION:In a three port three position flow amount control valve 21 used in intake/exhaust operation of a height regulating cylinder for an automobile, a main spool 23 is fit to a valve main body 22, a pilot spool 36 is fit in the main spool 23, and pilot pressure chambers 36, 38 are formed on both ends thereof. The pilot pressure chamber 36 is communicated with a drain chamber 27, and both chambers 36, 38 are communicated with each other through an orifice 39. The pilot spool 36 is displaced by a proportional solenoid 25 through an operating rod 45, and the main spool 23 is displaced proportionally to boosted pilot pressure so as to switch a flow passage when a pilot side pump port 46 or a pilot side tank port 47 is communicated with a pilot pressure passage 43.

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 or the like for controlling the attitude of an automobile.

[0002]

2. Description of the Related Art In a suspension system of an automobile, there is known a suspension control system which automatically suppresses a change in posture of a vehicle body during traveling to improve steering stability and riding comfort. Generally, in a suspension control device, pressure fluid (oil liquid) is supplied to and discharged from a vehicle height adjustment cylinder that is interposed between a wheel and a vehicle body by using a flow control valve according to road surface conditions, running conditions, etc. I try to suppress changes in the body posture.

An example of a conventional flow control valve provided in this type of suspension control device will be described with reference to FIG. As shown in FIG. 2, the flow rate control valve 1 is a 3-port 3-position pilot type proportional flow rate control valve and includes a valve body 2
A main spool 3 and a pilot spool 4 are slidably fitted therein. A pilot pressure chamber 5 and a drain chamber 6 are provided at both ends of the main spool 3, and a pilot pressure chamber 7 and a drain chamber 8 are provided at both ends of the pilot spool 4.

The valve body 2 is provided with a cylinder port 9 facing a main spool 3 and connected to a vehicle height adjusting cylinder (not shown), and a pump port 10 connected to a hydraulic pump (not shown). And a tank port 11 connected to a drain tank (not shown). The main spool 3 shuts off the cylinder port from the pump port 10 and the tank port 11 when in the neutral position shown in the figure, and connects the cylinder port 9 to the pump port 10 when moving to the drain chamber 6 side. The cylinder port 9 is communicated with the tank port 11 when moved to the pilot pressure chamber 5 side. At this time, the cylinder port 9, the pump port 10 and the tank port 11 are communicated with each other in a passage area corresponding to the movement amount of the main spool 3. The drain chamber 6 is provided with a spring 12 for urging the main spool 3 toward the pilot pressure chamber 5 side, and an initial set load of the spring 12 can be adjusted by an adjusting screw 13 and a lock nut 14.

Further, the valve body 2 is provided with a pump port which faces the pilot spool 4 and is connected to a hydraulic pump.
15, a tank port 16 connected to the drain tank, and a pilot pressure passage 17 communicating with the pilot pressure chambers 5 and 7.
Is provided. The pilot pressure passage 17 is cut off from the pump port 15 and the tank port 16 when the pilot spool 4 is in the neutral position shown in the figure, and communicated with the pump port 15 when moved to the pilot pressure chamber 7 side.
When it moves to the drain chamber 8 side, it communicates with the tank port 16. The pilot pressure chamber 7 is provided with a spring 18 that biases the pilot spool 4 toward the drain chamber 8.

A proportional solenoid 19 for urging the pilot spool 4 to the pilot pressure chamber 7 side is attached to the drain chamber 8 side of the valve body 2. The proportional solenoid 19 is configured to generate a thrust force according to the energized current regardless of the expansion / contraction position of the operating rod 20.

Next, the operation of the flow control valve 1 will be described.

When the proportional solenoid 19 is energized to move the pilot spool 4 to the pilot pressure chamber 7 side, the pilot pressure passage 17 is communicated with the pump port 15 and the pressure in the pilot pressure chambers 5 and 7 (pilot pressure) rises. . As the pilot pressure increases, the pilot spool 4 is pushed back to the drain chamber 8 side, and the communication between the pilot pressure passage 17 and the pump port 15 is gradually cut off. Then, when the pilot pressure and the thrust of the proportional solenoid 19 are balanced, the rise of the pilot pressure stops. Further, if the thrust of the proportional solenoid 19 is reduced, the pilot spool 4 will move to the drain chamber 8
And the pilot pressure passage 17 is communicated with the tank port 16 to lower the pilot pressure. When the pilot pressure decreases, the pilot spool 4 moves to the pilot pressure chamber 7 side by the thrust of the proportional solenoid 19, so that the reduction of the pilot pressure stops when the pilot pressure and the thrust of the proportional solenoid 19 are balanced. At this time, since the thrust of the proportional solenoid 19 is proportional to the current, the pilot pressure also changes in proportion to the current.

On the other hand, the main spool 3 moves toward the drain chamber 6 side against the bias of the spring 12 by the pilot pressure acting on the pilot pressure chamber 5. Then, since the main spool 3 moves to a position where the pilot pressure and the biasing force of the spring 12 are in balance, by changing the pilot pressure by the current supplied to the proportional solenoid 19,
The main spool 3 can be moved to adjust the area of the communication passage between the cylinder port 9 and the pump port 10 and the area of the passage between the tank port 11 and the supply / exhaust oil flow rate of the vehicle height adjustment cylinder.

By increasing the pressure receiving area ratio between the main spool 3 and the pilot spool 4, the driving force applied to the main spool 3 can be increased even if the thrust of the proportional solenoid 19 is small.

[0011]

However, in the conventional pilot type proportional flow control valve 1 described above, since the main spool 3 and the pilot spool 4 are separately provided in the valve body 2, the total length becomes large and a large installation space is required. Need. Therefore, when applied to a suspension control device of a vehicle, there is a problem that there is a large restriction on the mounting space on the vehicle body.

The present invention has been made in view of the above points, and an object of the present invention is to provide a pilot type flow rate control valve which is downsized and improved in mountability on a vehicle body.

[0013]

The flow control valve of the present invention comprises:
In order to solve the above problems, a valve body, a cylindrical spool valve slidably fitted in the valve body, a pilot pressure chamber provided at one end of the spool valve, and the spool. A first urging means for urging the valve toward one end, and a pilot valve slidably provided in the spool valve for allowing pilot pressure to flow in and out of the pilot pressure chamber depending on a relative position to the spool valve, It is characterized by comprising a proportional solenoid for urging the pilot valve to one side and a second urging means for urging the pilot valve to the other side.

[0014]

With this structure, the spool valve and the pilot valve are integrated, so that the flow control valve can be downsized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In this embodiment, a 3-port 3-position flow control valve used for oil supply / discharge of a vehicle height adjusting cylinder of a vehicle suspension control device will be described.

As shown in FIG. 1, in the diversion control valve 21, a substantially cylindrical main spool 23, which is a spool valve, is slidably fitted inside a substantially cylindrical valve body 22, and both ends thereof are fitted. An adjusting screw 24 and a proportional solenoid 25, which will be described later, are attached, a pilot pressure chamber 26 is formed on one end side of the main spool 23, and a drain chamber 27 is formed on the other end side.

A cylinder port 28 connected to a vehicle height adjusting cylinder (not shown) and a pump connected to a hydraulic pump (not shown) on the side wall of the valve body 22 so as to face the main spool 23. Port 29 and drain tank (not shown)
And a tank port 30 connected to. When the main spool 3 is in the neutral position shown in the figure, it shuts off the cylinder port 28 from the pump port 29 and the tank port 30, and when the main spool 3 moves to the pilot pressure chamber 26 side (fueling position), the flow rate control unit 31 Through cylinder port 28
Is communicated with the pump port 29, and when moved to the drain chamber 27 side (oil discharge position), the cylinder port 28 is communicated with the tank port 30 via the flow rate control unit 32. At this time, the cylinder port 9, the pump port 10, and the tank port 11 communicate with each other in a passage area corresponding to the movement amount of the main spool 3.

The pilot pressure chamber 26 is provided with a spring 33 for urging the main spool 23 toward the drain chamber 27 side, and the drain chamber 27 has a first urging force for urging the main spool 23 toward the pilot pressure chamber 26 side. A spring 34 is provided as a means. The main spool 23 is normally biased toward the pilot pressure chamber 26 by the biasing force of these springs 33, 34, and the drain chamber is proportional to the increase in the pressure of the pilot pressure chamber 26 acting on the end portion. It is designed to move to side 27. Further, by moving the adjusting screw 24 and fixing it with the lock nut 35, the initial set load of the springs 33, 34 can be adjusted.

A pilot spool 36 is slidably fitted in the main spool 23 as a pilot valve. A plug 37 is attached to an opening of the main spool 23 on the pilot pressure chamber 26 side, and a pilot pressure chamber 38 is formed on one end side of the pilot spool 36. The pilot pressure chamber 38 is provided in the plug 37. The pilot pressure chamber 26 at one end of the main spool 23 is communicated with the orifice 39. The other end of the pilot spool 36 communicates with the drain chamber 27 of the main spool 23.

A pilot side pump port 40 is provided on the side wall of the main spool 23 so as to face the pilot spool 36.
And a pilot side tank port 41 is provided.
Further, inside the pilot spool 36, a pilot pressure passage 43 having one end communicating with the pilot pressure chamber 38 and the other end communicating with the valve groove 42 is provided. And the pilot spool
36 is the pilot pressure passage when in the neutral position shown in the figure.
When 43 is cut off from the pilot side pump port 40 and pilot side tank port 41 and moved to the pilot pressure chamber 38 side, the pilot pressure passage 43 is communicated with the pilot side pump port 40 via the valve groove 42, and the drain When moved to the chamber 27 side, the pilot pressure passage 43 communicates with the pilot side tank port 41 via the valve groove 43.

The pilot pressure chamber 38 is provided with a spring 44 as a second urging means for urging the pilot spool 36 toward the drain chamber 27. The tip end of the operating rod 45 of the proportional solenoid 25 is in contact with the end of the pilot spool 36 on the drain chamber 27 side. The proportional solenoid 25 is
Regardless of the expansion / contraction position of the actuating rod 45, thrust is generated according to the applied current and the pilot spool 36 is moved to the pilot pressure chamber.
It is designed to urge the 38 side.

Further, the side wall of the valve body 22 is provided with a pilot side pump passage 46 facing the pilot side pump port 40 of the main spool 23 and connected to a hydraulic pump (not shown). A pilot side tank passage 47 is provided facing the pilot side tank port 41 and connected to a drain tank (not shown). The pilot side pump port 40 is connected to the main spool 23.
Is in the neutral position or in the oil supply position on the pilot pressure chamber 26 side, it is communicated with the pilot side pump passage 46, and when it is in the oil drain position on the drain chamber 27 side, it is communicated with the pump port 29 so that it is always communicated with the hydraulic pump. It is located in. Further, the pilot side tank port 41 communicates with the pilot side tank passage 47 when the main spool 23 is in the neutral position or the draining position on the drain chamber 27 side, and when the main spool 23 is in the refueling position on the pilot pressure chamber 26 side, the tank port 30.
It is arranged so as to communicate with the drain tank at all times.

The operation of this embodiment having the above-mentioned structure will be described below.

[0024] The proportional solenoid 25 is energized to actuate the rod 45
Thus, when the pilot spool 36 is moved to the pilot pressure chamber 38 side, the pilot pressure passage 43 communicates with the pilot side pump port 40, and the pressure in the pilot pressure chamber 38 (pilot pressure) rises. As the pilot pressure increases, the pilot spool 36 is pushed back to the drain chamber 27 side, and the communication between the pilot pressure passage 43 and the pilot side pump port 40 is gradually cut off. Then, when the pilot pressure and the thrust of the proportional solenoid 25 are balanced, the increase of the pilot pressure stops. If the thrust force of the proportional solenoid 25 is reduced, the pilot spool 36 moves to the drain chamber 27 side, the pilot pressure passage 43 communicates with the pilot side tank port 41, and the pilot pressure decreases. When the pilot pressure decreases, the pilot spool 36 is driven by the thrust of the proportional solenoid 25.
Moves to the pilot pressure chamber 38 side, so that the pilot pressure stops decreasing at the time when the pilot pressure and the thrust of the proportional solenoid 25 are balanced. At this time, since the thrust of the proportional solenoid 25 is proportional to the current, the pilot pressure also changes in proportion to the current.

On the other hand, the pressure in the pilot pressure chamber 38 is transmitted to the pilot pressure chamber 26 via the orifice 39, and the pilot pressure in the pilot pressure chamber 26 moves the main spool 23 to the drain chamber 27 side. Then, the main spool 23 moves to a position where the pilot pressure and the biasing forces of the springs 33 and 34 are in balance. Therefore, the pilot pressure is adjusted by the current supplied to the proportional solenoid 19, and the main spool 23
Is moved to a desired neutral position, oil supply position or oil discharge position to adjust the communication passage area between the cylinder port 28 and the pump port 29 and the passage area between the tank port 30 and the vehicle height adjustment cylinder. The oil flow rate can be adjusted.

Since the main spool 23 is moved by the pilot pressure in this way, the driving force of the main spool 23 is increased even if the thrust of the proportional solenoid 25 is small due to the pilot pressure receiving area ratio of the main spool 23 and the pilot spool 36. can do.

Since the pilot spool 36 also moves with the movement of the main spool 23, the relative position of the pilot spool 36 and the proportional solenoid 25 changes. Regardless of this, since a constant thrust is generated, a predetermined pilot pressure can be maintained.

As described above, since the pilot spool 36 is provided inside the main spool 23 and the main spool 23 is driven by the pilot pressure, the driving force of the main spool 23 is increased and the main spool 23 and the pilot spool are driven. The spool 36 can be arranged integrally,
The external dimensions can be reduced as compared with the conventional pilot type flow control valve.

Further, a pilot side pump port for adjusting the pilot pressure according to the position of the main spool 23.
40 and the pilot side tank port 41 are connected to the main side pump port 29 and the tank port 30 to supply and drain oil on the pilot side, so the valve body of the pilot side pump port 40 and the pilot side tank port 41 The axial opening range on the 22 side can be reduced, and the overall length of the main spool 23 can be shortened.

In this case, when the main spool 23 is at the oil supply position, the pilot side pump port 40 is cut off from the pump port 29 so as to communicate with the pilot side pump passage 46. The pulsation due to refueling of the engine does not affect the pilot pressure. Similarly, when the main spool 23 is in the oil drain position, the pilot side tank port 41 is cut off from the tank port 30 so as to communicate with the pilot side tank passage 47. The pulsation associated with the oil drainage does not affect the pilot pressure.

In this embodiment, in order to shorten the total length of the flow control valve 21, the pilot side pump port 40 and the pilot side tank port 41 are connected to the main side pump port 29 and the tank according to the position of the main spool 23. port
The pilot side pump port 40 and pilot side tank port 41 are not connected to the main side pump port 29 and tank port 30, but the pilot side pump port 40 and pilot side tank port 41 are connected. Regardless of the position of the main spool 23, the passage 46 and the pilot side tank passage 47 are connected to the pilot side pump port 40.
Also, the pilot side tank port 41 may be always communicated.

In this embodiment, the three-port three-position flow control valve has been described as an example, but the present invention is not limited to this and can be similarly applied to other types of pilot type flow control valves. .

[0033]

As described in detail above, according to the flow control valve of the present invention, the spool valve and the pilot valve are integrated by arranging the pilot valve inside the spool valve. The valve can be miniaturized. As a result, the installation space for the flow control valve can be small,
In particular, when it is applied to a suspension control device of an automobile, it has an excellent effect that the mountability on the vehicle body can be greatly improved.

[Brief description of drawings]

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

FIG. 2 is a longitudinal sectional view of a conventional 3-port 3-position pilot type flow control valve.

[Explanation of symbols]

 21 Flow rate control valve 22 Valve body 23 Main spool (spool valve) 25 Proportional solenoid 26 Pilot pressure chamber 34 Spring (first biasing means) 36 Pilot spool (pilot valve) 44 Spring

Claims (1)

[Claims] 1. A valve body, a cylindrical spool valve slidably fitted in the valve body, a pilot pressure chamber provided at one end side of the spool valve, and the spool valve at one end side. A first urging means for urging the pilot valve, and a pilot valve slidably provided in the spool valve for allowing a pilot pressure to flow into and out of the pilot pressure chamber depending on a relative position to the spool valve; A flow control valve, comprising: a proportional solenoid for urging one side and a second urging means for urging the pilot valve to the other side.