JPH01261581A - Control valve - Google Patents

Abstract

PURPOSE:To reduce the pump delivery and the electric power consumption compared with a valve having a pilot passage by constituting such that the thrust of a proportional solenoid plunger is directly transmitted to a spool. CONSTITUTION:A spool 34 installed within a body is moved by the difference between a load pressure exerted on one end of the spool 34 and the thrust of a plunger 37 exerted on the other end of the spool 34. The thrust of the plunger 37 is variable according to the exciting current of a proportional solenoid SOL. By the movement of the spool 34, a load port S is communicated either to a supply port S or to a tank port T. A slide pin 44 is installed in one side of the spool 34. A stopper 36 is brought into contact with one side of the slide pin 44 while the other end of the spool 34 is made to face a pressure chamber P. The load port C is made to communicated with the pressure chamber P.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control valve that controls the pressure of, for example, a hydraulic suspension.

(Prior Art) The conventional control valve shown in FIG. 2 includes a spool valve SP containing a spool 2 and a proportional solenoid valve SV that controls the movement of the spool 2 in accordance with the load pressure. There is.

In the spool valve SP, a spool 2 is slidably housed in a body 3, one end of the spool 2 is covered with a cover member 4, and the other end is covered with a cover member 5. One end of the spool 2 thus configured faces a pressure chamber A formed on the cover member 4 side, and the other end faces a pressure chamber B formed on the cover member 5 side.

The pressure chamber A communicates with the load board C via a passage 6 formed in the cover member 4 and a passage 7 formed in the body 3. Further, the pressure chamber B is also communicated with the load port C, but it is communicated through the following flow path. That is,
Passage 8 formed in cover 5 → Passage 9 formed in body 3
→ Pilot flow path 11 with fixed throttle a → Annular groove 1
3, the pressure chamber B and the load port C are communicated with each other.

A spring 12 is interposed in the pressure chamber B,
The spring force of the spring 12 keeps the spool 2 in the normal position shown.

When the spool 2 of the spool valve SP is in the above normal position, the supply port S communicates with the load port C via the annular groove 15 formed in the spool 2, while the load port C → tank port The flow path of T is completely closed by a first land portion 29 formed on the spool 2.

Further, when the spool 2 moves to the left in the drawing, the flow path from the supply port S to the load bow) C is closed by the second land portion 30 formed on the spool 2, while the load port C is connected to the annular shape formed on the spool 2. It communicates with the tank port T via the groove 27.

And, even when spool 2 moves to any of the above positions,
Load port C is annular 1:1113 → fixed throttle a → passage 9
, 8 to the pressure chamber B, and also to the pressure chamber A via the passage 7.6.

In this way, pressure chamber A is directly connected to load port c, pressure chamber B
is connected to the load port c via the fixed throttle a, so the end face of the spool 2 on the pressure chamber A side has the load port c.
, and the pressure downstream of the fixed throttle a is introduced to the end face on the pressure chamber B side.

The above-mentioned pressures are applied to both end faces of the spool 2, and the spool 2 is moved by the differential pressure between the load port c and the pressure downstream of the fixed throttle a.

The proportional solenoid valve SV includes a solenoid S in the body 16.
A bearing member 17 having a shaft hole 18 is provided on the negative side thereof. Further, the outer surface of the bearing member 17 is covered with a cover member 19, and the valve chamber 20 is defined by the cover member 19 and the bearing member 17.

Further, a plunger 1 with a poppet 1a integrally formed thereon is attached to the shaft center of the solenoid SO, and one end of the plunger 1 defines a chamber r, and the other end of the poppet 1a is inserted into the shaft hole 18, and its tip is connected to the valve. It projects into the chamber 20. A passage 21 is formed in the plunger l at its axial center, and the valve chamber 20 and the chamber r are communicated through the passage 21, and a spring 22 is formed between the plunger l and the bearing member 17.
2 is interposed.

The plunger l thus constructed is maintained at the normal position shown in the figure by the action of the spring 22.

Furthermore, the cover member 19 includes a pilot flow path 23.
is formed, and one end thereof is opened to the valve chamber 20, and this opening corresponds to the tip of the poppet la. Further, the other end is communicated with the pilot flow path 10 of the spool valve SP, and the fixed throttle a
→It is communicated with the load port C via the annular groove 13.

The opening end of the pilot flow path 23 on the valve chamber 20 side is a flow path that is combined with the tip of the poppet 1a, and forms a variable throttle b.

A flow path 24 is further formed on one side of the cover member 19, one end of which opens into the valve chamber 20, and the other end communicates with a flow path 25 formed in the spool valve SP.

The valve chamber 20 and the tank port T are communicated via the flow path 25.

Proportional valve SV and spool valve SP constructed as described above
When the is in the normal state shown in the figure, when pressure fluid is supplied from a pump (not shown) to the supply port S, the pressure fluid flows from the supply port S to the annular groove 14 to the annular groove 1.
5 -> Annular groove 13 -> It is supplied to a cylinder (not shown) via load port C, and the pressure in the cylinder is increased.

Further, a part of this pressure fluid is separated as a control fluid in the annular groove 13, and this separated control fluid flows to the tank port T via the fixed throttle a and the variable throttle b. Return to the tank (not shown) from T. The control fluid is guided to pressure chambers A and B, and one end of the spool on the pressure chamber A side receives the pressure of the load port C, and the end of the spool on the pressure chamber B side receives the fixed throttle a. Downstream pressure acts.

In this state, when the proportional solenoid valve Sv is excited, a thrust corresponding to this exciting current is applied to the plunger 1, and this thrust causes the plunger 1 to move rightward in the drawing against the spring force of the spring 22.

When the plunger l moves in this manner, the pressure acting on the poppet tip 1a of the plunger 1 acts against the thrust of the plunger 1. Therefore, the plunger 1 stops at a position where the spring force and the above-mentioned pressure are balanced with the thrust of the plunger 1, and the opening degree of the variable throttle b is determined.

The controlled flow rate at this time is determined according to the opening degree of the variable throttle b, but in this conventional example, the pressure difference generated after the fixed throttle a'#J is applied to the spool 2 according to the control flow rate, The movement stroke of the spool 2 is controlled.

That is, when a pressure difference occurs before and after the fixed throttle a due to the controlled flow rate controlled according to the opening degree of the variable throttle b as described above, the fluid pressure on the upstream side of the fixed throttle a increases to the passages 7 and 6.
The pressure is transmitted to the pressure chamber A through the pressure chamber A, and acts on one end of the spool 2. Further, the fluid pressure on the downstream side of the fixed throttle a is transmitted to the pressure chamber B, which is the other end of the spool 2, via the passage 9.8, and acts on the other end of the spool 2.

Therefore, the spool 2 stops at a position where the pressure action in the pressure chamber A and the pressure and spring action in the pressure chamber B are balanced.

In this way, the control valve determines the opening degree of the variable throttle b in proportion to the excitation current of the solenoid S, and controls the differential pressure generated before and after the fixed throttle a by flowing a pilot flow rate according to this opening degree. are doing. Then, as mentioned above, variable aperture b
The fluid that has passed through is drained into the tank.

Further, the pressure upstream of the fixed throttle a controlled as described above is guided to the pressure chamber A facing one end of the spool 2, and the downstream pressure is guided to the pressure chamber B facing the other end of the spool 2. Therefore, a differential pressure across the fixed throttle a acts on the spool 2. The movement stroke of the spool 2 is controlled according to this differential pressure.

(Problems to be Solved by the Present Invention) The conventional control valve as described above controls the control flow rate by the opening degree of the variable throttle, and reduces the differential pressure before and after the fixed throttle that occurs according to the controlled flow rate. It acts on the spool. The fluid that has passed through the variable throttle is returned to the tank as drain.

Therefore, there is a problem in that the pump capacity must be increased by the above-mentioned control flow rate, and the power consumption of the pump also increases.

(Means for Solving Problems) This invention has a spool built into the body, applies load pressure to one end of the spool, contacts the plunger of a proportional solenoid to the other end, and responds to the excitation current of the proportional solenoid. The spool is configured to move in accordance with the difference between the thrust of the plunger acting on the spool due to the load pressure and the thrust of the spool due to the load pressure, thereby communicating the load port with the supply port or the load port with the tank port. Moreover, a slide pin is installed on one side of the spool,
One end of this is brought into contact with the stopper, while the other end faces the pressure, and this pressure chamber is communicated with the load port.

(Action of the present invention) Since the slide pin is housed inside the spool, the pressure receiving area of the slide bin can be freely reduced.

Therefore, the pressure receiving area of the slide bin can be reduced, and the thrust force acting on the spool due to the load pressure can be reduced.

Since the thrust of the spool due to the load pressure can be reduced in this way, the electromagnetic force of the proportional solenoid, which cannot exert a large thrust, can be made to oppose the load pressure. Therefore, the thrust of the spindle of the proportional solenoid can be applied directly to the spool.

(Effects of the present invention) Since the thrust of the proportional solenoid bra can be applied directly to the spool, there is no need to intentionally provide a pilot flow path and flow control fluid in accordance with the opening of the variable throttle through this flow path. . Therefore, the pump capacity can be reduced accordingly, and the power consumption of the pump can also be reduced.

(Embodiment of the present invention) In the embodiment of the present invention shown in FIG. 1, a spool 34 is slidably installed inside a body 31, and one end opening of the spool 34 is closed with a plug 35 to define a spring chamber R1. At the same time, screw the proportional solenoid SQL to the other end opening,
A spring chamber R2 is partitioned. And these spring chambers R1
, R2 communicate with the tank port T through passages 32 and 33 formed in the body 31, respectively.

Further, a stopper 36 is provided between one end of the spool 34 and the plug 35, and a spring B1 is interposed between the stopper 36 and the spool 34.
A spring 93 is provided between the other end and the proportional solenoid SQL, and a spring B2 is interposed between the spring receiver 38 and the spool 34.

Further, annular grooves 39 to 41 are formed on the outer periphery of the spool 34, and both ends of an introduction path 42 formed across the axis of the spool 34 are opened in the annular groove 40. Further, a pin hole 43 is formed at the axial center of the spool 34, one end of which opens into the introduction path 42, and a slide pin 44 is slidably housed in the other end. The pressure chamber P is defined by one end of the slide pin 44 and the pin hole 43, and the other end of the slide pin 44 is brought into contact with the stopper 36.

On the other hand, one end of the plunger 37 of the proportional solenoid SQL is brought into contact with one side of the spool 34, and the other end is connected to the spring B.
3 is interposed. In this way, the plunger 37
The spool 34 maintains the normal position shown in the figure, but the spool 34 at this time has the above-mentioned Bl provided at both ends of the spool 34,
The neutral position shown in the figure is maintained by the action of B2.

Thus, when the spool 34 is in the neutral position,
Land portions 4 formed on both sides of the annular groove 4o of the spool 34
5.46 closes the flow path between the load port c, the supply port s, and the tank port T. Further, the annular groove 40 is inserted through an annular groove 47 formed in the body 31.
The annular groove 40 is connected to the pressure chamber P via the introduction path 42, and the slide pin 44 whose one end faces the pressure chamber P is also connected to the load port C so that the fluid in the load port C is always guided. I have to.

Therefore, a pressing force due to the fluid pressure of the load port C is always applied to the tip of the slide pin 44, and the slide pin 44 is pressed against the stopper 36 by this pressing force. In this way, the slide pin 44 is connected to the stopper 36.
Therefore, the reaction force of the pressing force acting on the slide pin 44 acts on the spool 34. In the present invention, the reaction force acting on the spool 34 is transferred to the proportional solenoid SQL.
It is made to act against the thrust of the plunger 37.

If the spool 34 moves rightward in the drawing, the annular groove 38 of the spool 34 opens into the annular groove 47, and the supply port S opens into the annular groove 47 formed in the body 31.
-> Annular groove 38 -> Communicates with load port C via annular groove 47. Further, when the spool 34 moves to the left in the drawing in the opposite direction to the above, the annular groove 41 of the spool 34 opens into the annular groove 47, and the load port C opens from the annular groove 47 to the annular groove 41 to the body 31. Through the formed annular groove 49,
It is connected to tank port) T.

When the proportional solenoid soL is excited and a thrust corresponding to the exciting current is applied to the plunger 37, the plunger 37 moves the spool 34 to the right in the drawing against the spring force of the spring B1. In this state, supply port S
When the pressure fluid is supplied from the annular groove 48 → the annular groove 39 → the annular groove 47 → the load port c
It is supplied to a cylinder (not shown) via the cylinder, increasing the load pressure of the cylinder. Further, the fluid pressure on the load port c side at this time is guided to the pressure chamber P through the introduction path 42 and acts on the slide pin 44. The pressing force acting on the slide pin 44 acts on the spool 34 as a reaction force.

Therefore, the spool 34 stops at a position where the forces acting on the spool 34 and the slide pin 44 are balanced.

According to this embodiment as described above, the slide pin 44
Since this is installed inside the spool 34, the pressure receiving area of the slide pin 44 can be freely reduced, and the pressing force on the slide bin 44 due to the load pressure acting on the slide bin 44 can be reduced.

In this way, the pressing force acting on the slide bin 44 can be reduced, so as a reaction force to this pressing force.

The thrust acting on the spool 34 becomes smaller.

Therefore, the electromagnetic force of the proportional solenoid SQL, which cannot exert a large thrust, can be made to oppose the load pressure.

Therefore, the thrust of the plunger 37 of the proportional solenoid SQL can be applied directly to the spool 34.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an embodiment of this invention. FIG. 52 is a sectional view of a conventional control valve. C... Load port, S... Supply port, T... Tank port, 34... Spool, 36... Stopper, 37... Plunger, P... Pressure chamber, 44...
Slide bin, SQL...proportional solenoid. Agent Patent Attorney 1III3 Nobuyuki A I Zudai 2 Diagram

Claims (1)

[Claims] A spool is installed in the body, a load pressure is applied to one end of the spool, and a plunger of a proportional solenoid is brought into contact with the other end, and the thrust of the plunger that acts on the spool and the above load pressure are determined according to the excitation current of this proportional solenoid. The spool moves according to the difference in thrust between the spool and the spool, allowing the load port to communicate with the supply port or the load port with the tank port. A control valve that is installed internally and has one end in contact with a stopper, the other end facing a pressure chamber, and this pressure chamber communicating with a load port.