JPH085433Y2 - Flow control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a flow control valve capable of pressure compensation control.

(Prior Art) In the conventional flow control valve shown in FIG. 2, a pressure compensation valve portion VP and a flow control valve VF are arranged in parallel on the body 1.

In the pressure compensation valve portion VP, a sleeve 2 is fitted to the body 1, one end opening of the sleeve 2 is covered with a cover member 3, and the other end opening is covered with an adjusting screw 4.
The pressure compensating spool 5 is slidably inserted into the sleeve 2 thus configured, one end of the pressure compensating spool 5 is exposed to the pressure chamber 6 formed on the cover member 3 side, and the other end is adjusted by the adjusting screw 4. It faces the spring chamber 7 formed on the side.

The pressure chamber 6 communicates with the supply port 8 formed in the body 1, which is through the next flow path. That is, the pressure chamber 6 and the supply port 8 are passed through the flow passage 9 formed in the spool 5 → the annular groove 10 formed in the outer periphery of the spool 5 → the inflow port 11 formed in the sleeve 2.
And communicate with. Further, the spring chamber 7 communicates with an actuator port 13 formed in the body 1 through an outflow port 12 formed in the sleeve 2, and
A control spring 14 is interposed in the spring chamber 7.

The pressure compensating spool 5 thus configured maintains the illustrated normal position by the action of the spring 14, but when the spool 5 is in the normal position, the overlap amount between the annular groove 10 and the inflow port 11 is maximum. I am trying to become. The flow path determined by the amount of overlap between the annular groove 10 and the inflow port 11 is the first variable throttle a. Therefore, when the pressure compensation spool 5 is in the normal position, the opening area of the first variable throttle a is maintained at the maximum. When the spool 5 moves against the control spring 14, the opening area of the first variable diaphragm a is gradually reduced.

The spring force of the control spring 14 is the same as the adjustment screw 4
It can be adjusted by turning.

The flow control valve portion VF has a plug 16 that closes one end of a valve hole 15 formed in parallel with the sleeve 2, and a proportional solenoid 17 is screwed on the opposite side of the plug 16. A sleeve 18 is fitted in the valve hole 15, and a flow control spool 19 is slidably inserted in the sleeve 18. A spring 20 interposed between the flow control spool 19 and the plug 16 is made to act on one end of the flow control spool 19, and a push rod 21 of a proportional solenoid 17 is made to abut on the other end.

The flow control spool 19 as described above is a spring
The normal position shown in the figure is maintained by the action of 20, but when in this normal position, the first land portion of the spool 19 is concerned.
At 22, the intermediate port 23 formed in the sleeve 18 is completely closed. The intermediate port 23 is always in communication with the annular groove 10 of the pressure compensating spool 5 through the through hole 24 formed in the body 1 and the through hole 25 formed in the sleeve 2. And this spool 19 is the spring
When moved against 20, the intermediate port 23 causes the annular groove 27 formed between the first and second lands 22 and 26 of the spool 19 to move.
And it will be opened to the annular groove 27 side. In this way, the second variable throttle b is constituted by the flow path constituted by the intermediate port 23 and the annular groove 27 in combination.

The annular recessed groove 27 as described above is connected to the actuator port through the intermediate port 28 formed in the sleeve 18 → the through hole 29 formed in the body 1 → the annular recess 30 formed in the sleeve 2.
It is in continuous communication with 13.

Then, the proportional solenoid 17 is excited to move the flow control spool 19 against the spring 20, and the opening of the second variable throttle b is determined according to the exciting current.

When a discharge fluid from a pump (not shown) is supplied to the supply port 8 in this state, the pressure fluid is a first variable throttle a → annular groove 10 → second variable throttle b → annular groove 27 → annular recess 30 → It is supplied to an actuator (not shown) via the actuator port 13.

The supply flow rate at this time is determined by the opening degree of the second variable throttle b and the pressure difference before and after the second variable throttle b. In this conventional example, the differential pressure before and after the second variable throttle b is kept constant. The control flow rate is kept constant. That is, when the pressure fluid is supplied to the actuator as described above, the pressure on the supply side is transmitted from the flow path 9 to the pressure chamber 6 and acts on one end of the pressure compensation spool 5. Also,
Since the load pressure on the actuator side acts on the spring chamber 7 which is the other end of the pressure compensating spool 5, the pressure compensating spool 5 acts on the pressure in the pressure chamber 6 and the pressure and spring in the spring chamber 7. The operation is stopped at a position where the action is balanced, and the opening area of the first variable diaphragm a is specified.

In this way, when the pressure compensating spool 5 is stopped, for example, if the load pressure on the actuator port 13 side increases, the balance condition of the spool 5 is broken, so the pressure compensating spool 5 moves to the left in the drawing. , Increase the opening area of the first variable diaphragm a. If the opening area of the first variable throttle a increases, the pressure on the upstream side of the second variable throttle b increases accordingly, so that the differential pressure before and after the second variable throttle b is relatively kept constant. Be drunk Therefore, the control flow rate determined by the second variable throttle b is kept constant.

In contrast to the above, when the load pressure on the actuator port 13 side decreases, the pressure compensation spool 5 moves to the right in the drawing, and the opening area of the first variable throttle a is reduced. The smaller the opening area of the first variable diaphragm a, the more
Since the pressure on the upstream side of the variable throttle b decreases, the differential pressure across the second variable throttle b is kept constant. Therefore, also in this case, the control flow rate determined by the second variable throttle b is kept constant.

(Problems to be Solved by the Present Invention) The conventional flow control valve as described above has the pressure compensation valve section.
Since the VP and the flow rate compensation valve unit VF are provided in parallel in one body, there is a problem that the body becomes large and two sleeves 2 and 18 are required, and the number of parts increases. It was

The purpose of this invention is to make the body smaller and
It is an object of the present invention to provide a flow control valve that requires a small number of parts.

(Means for Solving Problems) This invention provides a body with a pressure compensating spool and a flow rate controlling spool. One end of the pressure compensating spool is supplied with a supply pressure, and the other end is supplied with a load pressure. The pressure compensation spool moves according to the difference between the two pressures to control the opening area of the first variable throttle, while the flow control spool has
The push rod of the proportional solenoid is brought into contact with one end of the proportional solenoid, and the flow rate control spool moves in accordance with the exciting current of the proportional solenoid, and the opening area of the second variable throttle located downstream of the first variable throttle. And the supply port and the actuator port are made to communicate with each other via these first and second variable throttles.

Then, on the premise of the above flow control valve, the present invention forms a recess at one end of a pressure compensation spool, and inserts one end of a sleeve for slidably supporting the control spool into the recess so that both spools are inserted. While arranging in series, the end of the compensating spool on the concave side faces the pressure chamber, and the end on the opposite side of the concave faces the spring chamber, which guides the load pressure to the spring chamber. A pressure on the downstream side of the first throttle and on the upstream side of the second throttle, and the flow control spool slidably supported in the sleeve is brought into contact with the push rod of the proportional solenoid at one end thereof. It is characterized in that the other end is exposed to a spring chamber different from that described above, and the load pressure is introduced into this spring chamber.

(Operation of the present invention) This invention detects the load pressure on the actuator side and controls the opening of the first variable throttle to keep the differential pressure before and after the second variable throttle constant. Even if the load pressure changes, the control flow rate can be kept constant.

(Effect of the present invention) According to the flow control valve of the present invention, since the pressure compensation spool and the flow control spool are arranged in series, the body can be downsized and the number of parts such as the sleeve can be reduced.

(Embodiment of the present invention) In the embodiment of the present invention shown in FIG. 1, two valve holes 32, 33 having different diameters are formed in series in a body 31, and the outside of the large-diameter valve hole 32 is formed. The opening is covered with a plug 34.

The large-diameter valve hole 32 thus constructed has a pressure compensation spool 35
The pressure compensation spool 35
A concave portion 36 is formed in this, and this concave portion 36 is opened to the side of the small-diameter valve hole 33. The spring chamber 37 faces the side opposite to the opening of the recess 36, and the spring force of the spring 38 provided in the spring chamber 37 acts on the pressure compensation spool 35.

A sleeve 39 is screwed into the valve hole 33 having the small diameter. The inner end of the sleeve 39 is covered with a lid member 40, and the tip of the sleeve 39 provided with the lid member 40 is pressed. It faces the recess 36 of the compensation spool 35.

The outer diameter of the sleeve 39 is smaller than the inner diameter of the recess 36, and the flow path is provided between the recess 36 and the sleeve 39.
41 is being formed. The pressure compensating spool 35 thus configured has an inner end formed with a pressure chamber 43 formed by the spool 35 and a step portion 42 formed at the boundary between the valve holes 32 and 33.
Facing the side. When the pressure in the pressure chamber 43 is the tank pressure, the pressure compensating spool 35 holds the illustrated normal position, and the intermediate port 44 formed in the spool 35 and the supply port 45 formed in the body 31 are combined. The opening area of the first variable diaphragm a to be formed is kept at the maximum. Further, the spring chamber 37 has a flow path 46 formed in the body 31.
Also, the body 31 and the sleeve 39 are in constant communication with the actuator port 48 via an annular chamber 47 formed by combining them.

Further, a flow rate control spool 49 is slidably installed in the sleeve 39, and a proportional solenoid 50 is screwed into an outer opening portion thereof. One end of the flow rate control spool 49 faces the spring chamber 51, and the spring force of the spring 52 provided in the spring chamber 51 is applied to the spool.
Acting on 49. Therefore, the flow control spool 49
The spring 52 causes the outer end of the spring 52 to contact the push rod 53 of the proportional solenoid 50.

Then, when the flow rate control spool 49 is in the normal position shown, the second variable throttle b formed by the intermediate port 54 formed in the sleeve 39 and the annular groove 55 formed in the flow rate control spool 49 is closed. There is.

The intermediate port 54 is always in communication with the pressure chamber 43, while the annular groove 55 is always in communication with the actuator port 48 via the through hole 56 formed in the sleeve 39.

Then, when the proportional solenoid 50 is excited and the flow control spool 49 is pushed by the push rod 53, the second variable throttle b
However, the opening degree is controlled according to the exciting current of the proportional solenoid 50.

In this way, if the opening degree of the second variable aperture b is determined,
The pressure fluid is supplied from the supply port 45. The pressure fluid supplied to the port 45 is supplied to the actuator via the first variable throttle a → the passage 41 → the pressure chamber 43 → the second variable throttle b → the annular groove 55 → the actuator port 48.

Since the load pressure on the actuator port 48 side at this time is transmitted to the flow path 46 and also acts on the spring chamber 37, the pressure compensating spool 35 is disposed inside the pressure chamber 43 located upstream of the second variable throttle b. And the pressure and spring action in the spring chamber 37 on which the load pressure on the actuator side acts are stopped at a position where they balance, and the opening degree of the first variable throttle a is controlled.

When the pressure compensating spool 35 is stopped in this way, for example, if the load pressure on the actuator port 48 side rises, the balance condition of the spool 35 is broken, so the pressure compensating spool 35 moves to the right in the drawing. , Increase the opening area of the first variable diaphragm a. If the opening area of the first variable throttle a increases, the pressure on the upstream side of the second variable throttle b increases accordingly, so that the differential pressure before and after the second variable throttle b is relatively kept constant. Be drunk Therefore, the control flow rate determined by the second variable throttle b is kept constant.

Contrary to the above, when the load pressure on the actuator port 48 side becomes low, the pressure compensating spool 35 moves to the left in the drawing, reducing the opening area of the first variable throttle a. The smaller the opening area of the first variable diaphragm a, the more
Since the pressure on the upstream side of the variable throttle b decreases, the differential pressure across the second variable throttle b is kept constant. Therefore, also in this case, the control flow rate determined by the second variable throttle b is kept constant.

According to the embodiment as described above, the pressure compensation spool
Since the 35 and the flow control spool 49 are arranged in series, the body 1 can be downsized, and only one sleeve 39 is required. Moreover, in this embodiment, the tip of the sleeve 39 is made to face the recess 36 of the pressure compensation spool 35, and the flow path 41 is formed in the recess 36, and the flow path 41 and the second
Since the pressure chamber 43 is formed in the process of communicating with the variable throttle b, the axial length thereof can be shortened and the size can be further reduced.

[Brief description of drawings]

Drawing FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional flow control valve. 31 ... Body, 35 ... Pressure compensation spool, 45 ... Supply port, 48 ... Actuator port, 49 ... Flow control spool, a ... First variable throttle, b ... Second variable throttle, 50
…… Proportional solenoid, 53 …… Push rod.

Claims (1)

[Scope of utility model registration request] 1. A body is provided with a pressure compensating spool and a flow control spool, a supply pressure is applied to one end of the pressure compensating spool, and a load pressure is applied to the other end of the pressure compensating spool. The compensating spool moves to control the opening area of the first variable throttle, while the flow control spool has one end thereof in contact with the push rod of the proportional solenoid,
The flow rate control spool moves in accordance with the exciting current of the proportional solenoid to control the opening area of the second variable throttle located downstream of the first variable throttle, and to control the supply port and the actuator port. These first and second
In the flow control valve that is made to communicate through the variable throttle,
A recess is formed at one end of the pressure compensation spool, and one end of a sleeve that slidably supports the control spool is inserted into the recess to arrange both spools in series, while the end of the compensation spool on the recess side. Part facing the pressure chamber, the end opposite to the concave part faces the spring chamber, the load pressure is introduced to the spring chamber, and the pressure chamber is downstream of the first throttle and is more downstream than the second throttle. The flow rate control spool which guides the pressure on the upstream side and is slidably supported in the sleeve has one end contacting the push rod of the proportional solenoid and the other end facing a spring chamber different from the above. , This spring chamber is a flow control valve configured to guide the load pressure.