JPH0235205A - Fluid controller - Google Patents

Abstract

PURPOSE:To simplify a circuit constitution by balancing the pressure of valve bodies of respective main valves and constituting a pilot valve of a proportional control valve for proportionally controlling a pilot pressure. CONSTITUTION:The valve bodies 12 to 42 of respective main valves 10 to 40 are slidably inserted into respective valve holes with a pressure balanced. A pilot valve for controlling the operation of the respective main valves 10 to 40 is constituted of a pressure reducing valve 51 and first to fourth current control relief valves 52 to 55. Thereby, a change over valve for communicating and disconnecting a part between the fourth oil chambers R14 to R44 of the respective main valves 10 to 40 and a return oil passage P5 is not required, so that a circuit constitution can be simplified.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fluid control device that controls the operation of a fluid actuator (cylinder) by pilot operating four Popes L-type main valves. a Bopeso L-type first main valve that controls communication between the supply channel and the other load channel; a Bopeso 1-type second main valve that controls communication between the supply channel and the other load channel;
a poppet type third main valve that controls communication between the discharge flow path and one load flow path; a poppet L-type fourth main valve that controls communication between the discharge flow path and the other load flow path; The present invention relates to a fluid control device including a pyro, 1, and a valve that controls the operation of the 1st to 4th main valves.

[Prior art]

This type of fluid control device is known, for example, from Japanese Patent Application Laid-Open No. 62194, 0
This is proposed in Publication No. 07. However, in the fluid control device proposed in the same publication, each main valve has small diameter holes of the same diameter at both ends of a large diameter hole, and a valve seat is formed in one step. a valve body, and a valve that is inserted into the large diameter hole to form a first oil chamber that constantly communicates with one flow path, and that opens and closes the valve seat by seating on and leaving the valve seat;
7I valve part and the same valve part 1 are provided on one side of the valve part, extend into the small diameter hole of the one, and communicate with the first oil chamber through the valve seat between the small diameter hole and the other flow path. A connecting portion that forms a second oil chamber that communicates with the connecting portion; and a piston portion that is provided on one side of the connecting portion and is slidably inserted into the one small diameter hole and forms a third oil chamber at the end of the small diameter hole. A second hole is integrally provided and is provided on the other side of the poppet valve part, is slidably inserted into the other small diameter hole, and is connected to one end of the small diameter hole via a throttle. 4. The valve body is integrally provided with a small thread portion forming an oil chamber, and a spring that urges the valve body toward the third oil chamber. A proportional control valve that proportionally controls the pilot operation applied to the third oil chamber of each main valve according to the current applied value, and the fourth oil chamber and return flow path when the pressure is less than a set value. The fourth oil chamber is provided with a switching valve that cuts off communication between the fourth oil chamber and the return flow path when the pressure is equal to or higher than a set value.

[Problem to be solved by the invention]

By the way, the pie of the conventional fluid control device described above is
The switching valve in the valve is configured such that the fourth oil chamber of each main valve communicates with a flow path that communicates with the first or second oil chamber via a throttle. is less than the set value, the poppet valve portion of the valve body is pressed against the valve seat so that the pressure in the flow path communicating with the first or second oil chamber is applied to the fourth oil chamber via the restriction. It has a function of strongly pressurizing and preventing leakage at the same portion, and also preventing leakage from the fourth oil chamber to the return flow path, thereby reliably preventing leakage at each main valve.

However, among the various circuits used in the fluid control device, there are many circuits that do not require the reliable leak prevention function (pressure holding function) described above, and in such circuits, the function of the switching valve described above may be of excessive quality. Become.

The present invention has been made with attention to the above-mentioned viewpoints, and provides an inexpensive first fluid control device suitable for a circuit that does not require a reliable pressure holding function, and a circuit that does not require a reliable pressure holding function. It is an object of the present invention to provide a second fluid control device which is inexpensive and has a counterbalance function.

[Means to solve the problem]

The first fluid control device described in ``2'' has a valve body in which each main valve has a large diameter hole, and small diameter holes of the same diameter are provided at both ends of the valve body, and a valve seat is formed in one step. A poppet valve part that is fitted into the large diameter hole to form a first oil chamber that is always in communication with one of the flow paths, and that opens and closes the valve seat by seating on and leaving the valve seat; A connecting portion provided on one side, extending into the one small diameter hole, and forming a second oil chamber communicating with the first oil chamber through the valve seat and communicating with the other flow path between the small diameter hole and the first small diameter hole. and a piston part provided on one side of the connecting part and slidably inserted into the one small diameter hole to form a third chamber at the end of the small diameter hole. a valve body integrally provided with a small diameter portion provided on the other side and forming a fourth oil chamber that is slidably inserted into the other small diameter hole and returns to the end of the small diameter hole and communicates with the flow path; The pilot valve is configured to include a spring that biases the body toward the third oil chamber, and the pilot valve is configured to apply pressure to the third oil chamber of each of the main valves according to the current applied value. This can be achieved by having a configuration that includes a proportional control valve that proportionally controls.

Further, in the above-mentioned second fluid control device, the third main valve or the fourth main valve is provided with a small diameter hole having the same diameter at both ends of a large diameter hole, and a valve seat is formed in one stepped portion. a valve body which is fitted into the large-diameter hole to form a first oil chamber that is always in communication with the load flow path, and which opens and closes the valve seat by seating on and leaving the valve seat. A first oil chamber is provided on one side of the valve portion and the poppet valve portion, extends into the one small diameter hole, and communicates with the first oil chamber through the valve seat between the small diameter hole and the first oil chamber and the discharge flow path. A connecting portion that forms two oil chambers and a third oil chamber that is provided on one side of the connecting portion and is slidably inserted into the one small diameter hole and returns to the end of the small diameter hole and communicates with the flow path. Screws to do
- A fourth oil chamber is integrally provided with a seventh part and is provided on the other side of the poppet valve part and is slidably inserted into the other small diameter hole and returns to the end of the small diameter hole and communicates with the flow path. At the same time, a small diameter portion is integrally provided at the end of the large diameter hole to form a fifth oil chamber that communicates with the load flow path via a throttle, and the valve body is directed toward the third oil chamber. The configuration includes a biasing spring, and a valve that controls the operation of the third main valve or the fourth main valve is connected to the fifth oil chamber and provided through the throttle. A relief valve that is operated by the pressure of the load flow path, an on-off valve that is interposed in the flow path that connects this relief valve and the return flow path and opens and closes communication between the relief valve and the return flow path, and this on-off valve. This can be obtained by having a configuration including a pilot pressure supply valve that supplies pilot pressure for opening the opening/closing valve to the opening/closing valve.

[Action of the invention]

In the first fluid control device according to the present invention, the pressure is balanced so that the valve body of each main valve is not pushed by fluctuations in the oil pressure in the first oil chamber and the second oil chamber.
By appropriately changing the current value of the proportional control valve in the valve and appropriately changing each pilot pressure applied to the third oil chamber of each main valve, the following operations can be obtained.

(al) When the current applied value of the proportional control valve in the P-Irosoto valve is less than the set value (sometimes zero) and each pilot pressure is less than the set value.

At this time, pilot pressure is applied to the third oil chamber of each main valve, but since each pilot pressure is less than the set value, each pilot pressure pushes the valve body of each main valve against the action of the spring. It cannot move, and the valve parts 1 to 1 are seated on the valve seat. Therefore, communication between the flow path communicating with the first oil chamber and the flow path communicating with the second oil chamber of each main valve is maintained in a state of being cut off, the pressure in each load flow path is maintained, and the load flow A fluid actuator connected to the channel is held stationary under load.

(b) From the state of (a) above, set the current applied value of the proportional control valve in the pie 1:2 valve to the set value or more to the first and fourth (or second and third) main valves. 3. When each pressure applied to the oil chamber exceeds the set value.

At this time, the valve bodies of the first and fourth (or second and third) main valves move to a position where the pressing force due to the pilot pressure in each third oil chamber and the acting force of the spring are balanced, and at that position. Retained. Therefore, the supply flow path and one load flow path (or the other load flow path) to the fluid actuator, and from the same fluid actuator to the other load flow path (or
A drive circuit is formed in which fluid flows through the load flow path (or one of the load flow paths) and the discharge flow path, and the fluid actuator is actuated.

Therefore, in this state, by changing the current applied value of the proportional control valve in the pa, iro, and throat valves, the first (or second)
Give a difference between the pyro-71-pressure to the main valve and the pilot pressure to the fourth (or third) main valve, and either the first (or second) main valve or the fourth (or third) main valve If one is fully open and the other is appropriately throttled, the operation of the fluid actuator can be controlled by meter-in or meter-out. Note that during the operation of such a fluid actuator, the meter input can be achieved by changing the pyro-/1-pressure of the first (or second) main valve and the pyro-somatic pressure of the fourth (or third) main valve. It is possible to change from control to meter-out control (or vice versa). Additionally, when the pilot pressure to the third (or fourth) main valve is set to a value higher than the set value while the fluid actuator is in operation, the pressure is supplied to the fluid actuator through the first (or second) main valve. Part or all of the pressure fluid is discharged to the discharge passage through the third (or fourth) main valve, and the operation of the fluid actuator is controlled to reduce the pressure or control the bleed-off.

On the other hand, in the second fluid control device according to the present invention,
In place of the operation of 2 (bl), the following (C1 operation) can be obtained.

(C) Increase the pressure of the first (or second) main valve to a set value or higher, and operate the pilot pressure supply valve at the pilot pressure that controls the operation of the fourth (or third) main valve. When the on-off valve is opened.

At this time, the valve body of the first (or second) main valve moves to a position where the pressing force due to the spring in the third oil chamber is balanced and is held at that position. However, unless the relief valve in the pilot valve attached to the fourth (or third) main valve is opened, the hydraulic pressure in the first oil chamber and the fifth oil acting on the poppet valve part of the valve body in the main valve will be affected. Since the indoor oil pressure is offset, the fourth (
or 3) it does not move against the action of the valve body spring of the main valve. Therefore, the relief valve opens when the pressure inside the load flow path applied to the relief valve through the throttle exceeds the relief set pressure, and in such a case, the fourth (or third) main valve opens. A pressure difference is generated between the first oil chamber and the fifth oil chamber, and the valve body moves against the action of the spring in response to the pressure difference. Therefore, the fluid actuator operates under counter-harass control.

〔Effect of the invention〕

The first fluid control device according to the present invention has a variety of control functions equivalent to those of the conventional device described above, and has a fourth fluid control device for each main valve.
The oil chamber is only connected to the return flow path, and the circuit configuration is simplified compared to the conventional device described above.Moreover, the bilithoscopic 1-valve is connected to the main valve's main valve according to the current applied value. It is composed of a proportional control valve that proportionally controls the pressure (pylon attached to the 3rd oil chamber), and is used in the conventional device described above to disconnect communication between the 4th oil chamber of each main valve and the return flow path. Since the conventional switching valve is not employed, the fluid control device can be constructed at an extremely low cost compared to the conventional device described above.

Furthermore, in the second fluid control device according to the present invention, the fourth oil chamber of each main valve only communicates with the return flow path, and the circuit configuration is simplified compared to the conventional device. , Moreover, the Byron [- valve proportionally controls the pilot pressure applied to the third oil chamber of the three main valves, the first and second main valves and either the third or fourth main valve, according to the current applied value. It is composed of a proportional control valve to control, a relief valve opening/closing valve and a pilot pressure supply valve to control the operation of the fourth or third main valve,
Since the conventional device described above does not use the switching valve that is used to cut off communication between the fourth oil chamber of each main valve and the return flow path, the fluid control device is equipped with a counterbalance control function. Nevertheless, it can be constructed at a lower cost than the above-mentioned conventional devices.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of a first fluid control device according to the present invention, which includes a supply flow path P1 and one load flow path R.
a poppet-type first main valve 10 that controls communication between the two, a poppet-type second main valve 20 that controls communication between the supply flow path P1 and the other load flow path 23, and a poppet-type second main valve 20 that controls communication between the supply path P1 and the other load flow path 23; A Bopeso type third main valve 30 that controls communication between the flow path R2;
A fourth main valve 40 of a bope throat type that controls communication between the discharge flow path P4 and the other load flow path 23, and each of the main valves 10, 20, 30.
．． The pressure reducing valve 51 and the first to fourth current control relief valves 52 to 55 each function as a virion L-valve to control the operation of the valves 40 and 40, respectively.

Each main valve 10.20, 30.4.0 has the same basic configuration, and as shown in FIGS. 1 and 2 using the first main valve 10 as an example, the first member IIA, second member 11
The valve body 11 is composed of a valve body 11 made up of a third member 11C, a valve body 12 that is slidably inserted in the valve body 11 in the left-right direction, and a spring 13 that biases the valve body 12 leftward. has been done.

The valve body 11 has small diameter holes 11b and llc of the same diameter on both left and right sides of a large diameter hole 11a, and valve seats 1.1. an annular groove 1.1e formed at the end of the large-diameter hole on the side close to the valve seat lid and through which the load flow path P2 communicates, and a small-diameter hole on the left side. It has an annular groove 11f formed in the middle part of the groove 11b and communicating with the supply flow path P1.

The valve body 12 is slidably inserted into the large diameter hole 11a in a pressure-balanced state to form a first oil chamber R11. a Pobe 1 valve portion 12a that disconnects communication between the flow paths PI and P2;
A small diameter hole 11b is provided on the left side of the bovent valve part 12a.
A connecting portion 1 that extends inward and forms a second oil chamber R12 that communicates with the first oil chamber RI L through the valve seat lid between the small diameter hole and the small diameter hole.
2b, and a small diameter hole 11 provided on the left side of the connecting portion 12b.
The poppet valve portion 12 is integrally provided with a piston portion 12c that is slidably inserted into the small diameter hole 11b and forms a third oil chamber R13 to which pilot pressure is applied to the end of the small diameter hole 11b.
A fourth hole is provided on the right side of a, is slidably inserted into the small diameter hole 11c, and always returns to the end of the small diameter hole 11b and communicates with the flow path P5.
An oil chamber R14 is formed and a throttle 1 is provided at the end of the large diameter hole 11a.
It is integrally provided with a small diameter cylindrical portion 12d forming a fifth oil chamber R15 communicating with the load flow path P2 via a small diameter cylinder portion 12d.

Therefore, in the middle part of the above-mentioned screw l-7 part 12c,
It communicates with the second oil chamber R12 through a communication path consisting of an inner hole (closed by a plug 12e) provided in the axial direction at the axes of the piston portion 12c and the connecting portion 12b, and a radial hole provided in the connecting portion 12b. An opening 12c1 is formed to connect the opening 12c1, the small diameter hole inner wall 11b1, and the annular groove 1.
1f, the valve body 12 moves to the right, resulting in Bopeno I.

A variable throttle portion S is configured, the flow path area of which is always smaller than the flow path area formed between the tapered surface 12a1 of the valve portion 12a and the valve seat lid. Note that one of the shapes illustrated in FIG. 3 is adopted as the shape of the opening 12c1.

Note that corresponding members of the second to fourth main valves 20, 30.4.0 are given similar symbols and their explanations are omitted. (See Fig. 1) In each of the main valves 1o to 4o configured as described above, the first and fifth oil chambers R11 to R4, lR15 to The pressing force due to the hydraulic pressure inside R45 is canceled out, and the pope・71・valve part 12
a to 42 a and the pressing forces acting on the piston portions 12 c to 42 c due to the hydraulic pressure in the second oil chambers R12 to R4-2 are offset, so the valve bodies 12 to 42 are in the same position as the first. Second. 5th oil chamber R
No. 11 to R41, R12 to R42, and R15 to R45 are not pushed or moved by fluctuations in oil pressure (pressure is balanced). In addition, in each of the main valves 1o to 4o, the tapered surfaces 12a1 to 42a of the poppet valve portions 12a to 4.2a
The flow path formed between the valve seats lid and 41d functions as a mere passage, and the fluid is throttled by the variable throttle section S, so that the flow force acting on the valve bodies 12 to 42 (valve bodies 12 to 42 in the axial direction (the force that tries to move it) can be reduced, and the opening area of the variable aperture section S, which is set to a desired value, has the advantage that it is not so affected by the flow force. .

The pressure reducing valve 51 is connected to the supply flow path P1, and controls the pressure reduction of the oil pressure supplied from the flow path P1 to a predetermined value of the reference bar 1' loft. Each of the current control relief valves 52 to 55 is connected to the pressure reducing valve 51 via each of the throttles 56 to 59, and applies current to the pilot pressure applied to the third oil chambers R13 to R43 of each of the main valves 1o to 4o. Proportional control is performed according to each value.

In this embodiment configured as described above, the valve bodies 12 to 42 of each main valve are the first. The pressure is balanced so as not to be pushed by fluctuations in the oil pressure in the second and fifth oil chambers, and the current control relief valves 52 to 55 in the pilot valves are
The following operations can be obtained by appropriately changing the current application value and appropriately changing each pilot pressure applied to the third oil chambers R13 to R43 of each main valve 10 to 4o.

(]) When the current application value of each lightning current control leaf valve 52 to 55- is less than the set value (sometimes zero) and each pilot pressure is less than the set value.

At this time, the third oil chambers R13 to R of each main valve 10 to 40
43, but since each pilot pressure is less than the set value, the valve bodies 12 to 42 of each main valve are pushed by the respective bipolar pressures against the action of the springs 13 to 43. Valve parts 12a to 42
A is seated on the valve seats 11d to 41d. therefore,
Communication between the passages communicating with the first oil chambers R11 to R41 and the passages communicating with the second oil chambers R12 to R4, 2 of each main valve 10 to 40 is maintained in a state of being cut off, and each load flow Road P2゜R
The pressure of P2.3 is maintained, and the pressure of P2.3 is maintained. The fluid actuator A connected to P3 is held in a stopped state even when a load is applied.

(2) From the state of (1) above, the current control relief valve 5
The first and fourth (or second and third) main valves 10 are set so that the current applied value of 2.55 (or 53.54) is equal to or higher than the set value.
, 40 (or 20.30) third oil chamber R13, R43
(or R23, R33) when each pilot pressure applied to the set value or more.

At this time, the valve bodies 12, 42 (or 22, 32) of the first and fourth (or second and third) main valves are connected to each third oil chamber R.
13, R43 (or R23, R33) to a position where the pressing force due to the pilot pressure and the acting force of the spring 13.43 (or 23.33) are balanced and held at that position. Therefore, the supply flow path P1 and one load flow path P2 (or the other load flow path P3) are passed to the fluid actuator A, and from the same fluid actuator A, the other load flow path P3 (or one load flow path P2) and Discharge channel P
A drive circuit is formed through which fluid flows, and fluid actuator A is actuated.

Therefore, in this state, the current control relief valve 52.5
5 (or 53,54)-- by changing the current applied value to the pilot pressure to the first (or second) main valve 10 (or 20) and the fourth (or third) main valve 40 (or 30) = The first (or second) main valve 10 (
or 20) and the fourth (or third) main valve 40 (or 30)
By setting either one of the two to a fully open state and the other to an appropriate throttle state, the operation of the fluid actuator can be controlled to be make-in or meter-out. Note that during the operation of the fluid actuator A, the pilot pressure of the first (or second) main valve 10 (or 20) and the fourth (or
Alternatively, by changing the pilot pressure of the third) main valve 40 (or 30), it is possible to change from meter-in control to meter-out control (or vice versa). Also, during actuation to such a fluid actuator, the third (or fourth)
) When the pilot pressure to the main valve 30 (or 40) is set to a value higher than the set value, the first (or second) main valve 10 (
or 20), part or all of the pressure fluid supplied to the fluid actuator A is discharged to the discharge passage P4 through the third (or fourth) main valve 30 (or 40), and the operation to the fluid actuator is Controlled by pressure reduction or bleed-off.

(3) Current control IJ The current applied value of the leaf valves 52, 53-. If the value is greater than or equal to the set value.

At this time, the valve bodies 1222 of the first and second main valves are in the respective third oil chambers R13, F! It moves to a position where the pressing force due to the pilot pressure in 23 and the acting force of the spring 13.23 are balanced, and is held at that position. Therefore, the supply flow path P
1 communicates with the reload flow path P2P3, a differential circuit is formed, and the fluid actuator A operates at high speed. In addition, in this state, a difference is given to the pilot pressures to the first and second main valves 10.20, so that the supply flow path P1 and one of the load flow paths P2
Alternatively, by narrowing the range between 23 and 23, the operation of the fluid actuator A can be controlled in a meter-in or meter-out manner.

As is clear from the above description, the fluid control device of this embodiment uses the current applied value of each current control relief valve 52 to 55 in the pyro 7F valve, which is a component of the fluid control device, as a set value. 2, it is possible to perform meter-in or meter-out control of the operation of the fluid actuator without adding other parts (A) or control valves, and the device can be configured compactly and inexpensively. .

In addition, the above-mentioned meter-in or meter-out control characteristics can be changed as appropriate by appropriately changing the current application value of each current control relief valve 52 to 55-, and setting each pilot pressure to an appropriate value higher than the set value. It is possible to change the characteristics very easily.

Furthermore, each current control relief valve 52 in the pilot valve
By controlling the operation of ~55 with a time constant, each main valve 10~
Since the opening/closing operation speed of the fluid actuator 40 can be controlled, it is also possible to expect the effect of reducing the strain caused when the fluid actuator A starts or stops operating.

In addition, in the fluid control device of this embodiment, each main valve 10
The fourth oil chambers R14 to R44 of 40 are connected to the return passage P5, and the circuit configuration is, for example, according to JP-A-62-1.
It is simplified compared to the conventional device proposed in Publication No. 94.007, and moreover, the pressure reducing valve 51 is replaced by the pressure reducing valve 51.
and current control relief valves 52 to 55, etc., and employs a switching valve that is used in the conventional device described above to cut off communication between the fourth oil chamber of each main valve and the return flow path. Therefore, the fluid control device can be constructed at a much lower cost than the conventional devices described above.

FIG. 4 shows an embodiment of the second fluid control device according to the present invention, in which the third oil chamber R43 of the fourth main valve 40 communicates with the return passage P5, and the current control device The relief valve 55 functions as a pilot pressure supply valve (therefore, the valve 55 may be an electromagnetic switching valve, in which case the throttle 59 can be omitted), and the fifth valve of the fourth main valve 40
A relief valve V1 is connected to the oil chamber R45, and a flow path P that connects this relief valve ■1 and the return flow path P5.
The structure is the same as that of the fluid control device of the above embodiment, except that an on-off valve 2 for opening and closing communication between the relief V1 and the return flow path P5 is installed in the 6, and the same components are the same. Reference numerals are given and explanations thereof are omitted.

IJ IJ-F valve V1 is the fifth oil chamber R4 of the fourth main valve 40.
5, and is configured to be operated by the pressure of the load flow path P3 applied via the throttle 44. The on-off valve ■2 is a normally closed valve, and the current control IJ IJ-
The valve 55 is configured to open when a pilot pressure equal to or higher than a set value is applied from the valve 55.

In the fluid control device of this embodiment configured as described above, the following operation (4) can be obtained in place of the operation (2) above obtained in the fluid control device shown in FIG. The same operation as that obtained in the fluid control device shown in FIG. 1 can be obtained, except that the operation (3) cannot be obtained (because the configuration of the fluid actuator A is different).

(4) Set the pilot pressure of the first main valve 10- to a set value or higher, and operate the current control relief valve 55 in the pilot valve that controls the operation of the fourth main valve 40 to open/close the valve V2.
When activated to open.

At this time, the valve body 12 of the first main valve moves to a position where the pressing force due to the bar pressure in the third oil chamber R13 and the acting force of the spring 13 are balanced and is held at that position. Unless the relief valve V1 attached to the valve 40 is opened, the hydraulic pressure in the first oil chamber R41 and the hydraulic pressure in the fifth oil chamber R45 acting on the poppet valve portion 42a of the valve body 42 in the main valve are offset. Therefore, the valve body 42 of the fourth main valve does not move against the action of the spring 43. However,
The relief valve ■1 is opened when the pressure inside the load flow path R3 applied to the relief valve V1 through the throttle 44 exceeds the relief set pressure, and in such a case, the fourth main valve 4
A pressure difference is generated between the first oil chamber R4,1 and the fifth oil chamber R45, and the valve body 42 moves against the action of the spring 43 in response to the pressure difference. Therefore, the fluid actuator operates under counterbalance control.

By the way, in the fluid control device of this embodiment, the fourth oil chambers R14 to R44 of each of the main valves 10 to 40 communicate with the return passage P5, and the circuit configuration is different from that of the conventional device described above. It is simplified as follows, and the pilot valve is the first valve. 3rd oil chamber R1 of 2nd and 3rd main valve 10.20.30
3. Current control IJ IJ-F valve 5 that proportionally controls the pilot pressure applied to R23, R33 according to the current applied value
2.53° 54, a relief valve Vl that controls the operation of the fourth main valve 40, an on-off valve V2, and a current control relief valve 55 that functions as a pilot pressure supply valve. Because the switching valve that is used to cut off communication between the fourth oil chamber of the main valve and the return flow path is not adopted, the above-mentioned conventional fluid control device is equipped with a counterbalance control function. It can be constructed at a lower cost than the other devices.

(Modifications) The fluid control device according to the present invention is not limited to the above-mentioned embodiments, and the main valves used in the device disclosed in Japanese Patent Application Laid-Open No. 62-194007 may be modified as appropriate. To be adopted.

■ Bi-Japanese-Soviet 1-valve as a pilot valve shown in Figure 7 of Japanese Patent Application Laid-Open No. 62-194.007, Patent Application No. 1988
- Adopt the Pi-Nippon-Soviet 1-valve, etc. used in the device of application No. 16614.

Modifications such as the following are possible.

In addition, in each of the above embodiments, a main valve in which a fifth oil chamber is formed which communicates with the first oil chamber via a throttle is used as each main valve, but if the fifth oil chamber and the throttle are connected, the counterbalance control function is achieved. It is necessary only for the main valve (the fourth main valve in Fig. 4) to obtain the above-mentioned characteristics, and is not necessary for other main valves. As shown in FIG. 8, it is also possible to eliminate the throttle and combine the first oil chamber and the fifth oil chamber.

Furthermore, in the device shown in FIG. 4 described above, the configuration of the fourth main valve is different from that of the other main valves, and a relief valve, an on-off valve, etc. are added to the fourth main valve to obtain a counterbalance control function. However, it is also possible to configure the third main valve in the same manner as the fourth main valve and add a relief valve, etc. so that the third main valve can provide a counterbalance control function. be.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of a first fluid control device according to the present invention, FIG. 2 is a detailed enlarged sectional view of the first main valve portion of the device shown in FIG. 1, and FIG. 2 is a diagram illustrating the shape of the opening shown in FIG. 2, and FIG. 4 is an overall configuration diagram showing an embodiment of the second fluid control device according to the present invention. Explanation of symbols 10 to 40...Main valve, 11...Valve body, 11a...
・Large diameter hole, ttb, tic...small diameter hole, 11d...
Valve seat, 12...valve body, 12a...bope/throat valve part,
12b...Connection part, 12G...Piston part, 12d
...Small diameter part, 13-43...Spring, 14-44...
- Throttle, 51... Pressure reducing valve, 52-55... Current control relief valve (proportional control valve), Pl... Supply flow path, R2
...One load flow path, R3...The other load flow path, R
4...Discharge flow path, R5...Return flow path, R11 to R4
1... First oil chamber, R12 to R4, 2... Second oil chamber,
R13~R4,3...Third oil chamber, R14~R4,4.
...4th oil chamber, R15-R45...5th oil chamber, Vl.
...IJ IJ-F valve, V2...Opening/closing valve.

Claims (2)

[Claims] (1) A poppet-type first main valve that controls communication between the supply flow path and one load flow path, a poppet-type second main valve that controls communication between the supply flow path and the other load flow path, and a discharge flow path. a poppet-type third main valve that controls communication between the flow path and one load flow path;
A fluid control device comprising: a poppet-type fourth main valve that controls communication between the discharge flow path and the other load flow path; and a pilot valve that controls the operation of the first to fourth main valves. The main valve includes a valve body having a large-diameter hole with small-diameter holes of the same diameter at both ends, and a valve seat formed in one step, and a flow path that is fitted into the large-diameter hole and has one flow path. A poppet valve portion is provided on one side of the poppet valve portion and extends into the one small diameter hole, and the poppet valve portion forms a first oil chamber in constant communication with the valve seat and opens and closes the valve seat by seating on or leaving the valve seat. A connecting portion is provided on one side of the connecting portion to form a second oil chamber that communicates with the first oil chamber through the valve seat and communicates with the other flow path between the small diameter hole and the first oil chamber through the valve seat. A piston part is integrally provided which is slidably inserted into the small diameter hole and forms a third oil chamber at the end of the small diameter hole, and is provided on the other side of the poppet valve part and is slidable into the other small diameter hole. a valve body integrally provided with a small diameter portion that is inserted into the small diameter hole and forms a fourth oil chamber that returns to the end of the small diameter hole and communicates with the flow path; and a spring that biases the valve body toward the third oil chamber. Further, the pilot valve is configured to include a proportional control valve that proportionally controls the pilot pressure applied to the third oil chamber of each of the main valves according to the current applied value. Device. (2) A valve main valve in which the third main valve or the fourth main valve is formed by providing a small diameter hole of the same diameter at both ends of a large diameter hole, and forming a valve seat in one step; A poppet valve part that is inserted into a large diameter hole to form a first oil chamber that is constantly in communication with the load flow path, and opens and closes the valve seat by seating on and leaving the valve seat, and one side of the poppet valve part a connecting portion that is provided in the one small diameter hole and forms a second oil chamber that extends into the one small diameter hole and communicates with the first oil chamber through the valve seat and communicates with the discharge flow path; A third portion is provided on one side of the portion and is slidably inserted into the one small diameter hole and returns to the end of the small diameter hole and communicates with the flow path.
A fourth integrally provided with a piston portion forming an oil chamber, and provided on the other side of the poppet valve portion and slidably inserted into the other small diameter hole and returns to the end of the small diameter hole and communicates with the flow path. a valve body integrally provided with a small diameter portion forming an oil chamber and a fifth oil chamber communicating with the load flow path via a throttle at the end of the large diameter hole; A pilot valve for controlling the operation of the third main valve or the fourth main valve is connected to the fifth oil chamber and the load is applied through the throttle. Relief valve operated by pressure in flow path,
An on-off valve that is interposed in the flow path that connects this relief valve and the return flow path to open and close communication between the relief valve and the return flow path, and a pilot that supplies pilot pressure to open the on-off valve to operate the on-off valve. The fluid control device according to claim 1, characterized in that the fluid control device includes a pressure supply valve.