JPS6035568B2 - hydraulic control valve device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control valve device for controlling the flow of a large capacity main circuit with the flow of a controlled small capacity pilot circuit used in a hydraulic circuit.

Conventional hydraulic control valve devices of this type are pilot-operated systems that use the flow in the pilot circuit to control the flow in the main circuit, but they also have a single function of directional control, pressure control, or flow rate control. When constructing a hydraulic control circuit, a combination of large-capacity control valves with different functions is used. Furthermore, when systematizing the valve as an integrated valve, it is inconvenient because it requires the use of many different types of single-function valves, and the disadvantage that the integration increases the external size and also affects the price is unavoidable. Also, as shown in, for example, JP-A-48-73823, JP-A-48-86121, and JP-A-49-3074, large flow control that operates according to the function of the pilot valve is also possible. Multifunction valves are also known.

In addition to the pilot flow rate detection orifice, these multi-function valves are equipped with an orifice for detecting the flow rate of the main flow in the part that controls the main flow, and the pressure difference generated at the orifice is fed back to the main control valve. The flow rate is adjusted, but with this type of control valve, if the main control flow rate is low, the pressure difference generated at the orifice will be too small and the accuracy of the control valve will deteriorate, so it is not suitable for small flow rate control. ,
When the controlled flow rate is large, the pressure difference at the orifice becomes large, and the minimum operating pressure difference during control, that is, the pressure loss as a control valve becomes large. Therefore, a wide range of control flow rates from small flow rates to large flow rates cannot be satisfied with a single control valve, and the disadvantage is that each control valve must be individually designed and adjusted according to the flow rate range in use. The present invention seeks to eliminate the above-mentioned drawbacks, and its main purpose is to provide a flow path for the main control flow in a multifunctional hydraulic control valve device that controls the flow in the main circuit in a pilot-operated manner. An object of the present invention is to provide a hydraulic control valve device that can control the main circuit flow with high accuracy in response to the pilot flow rate over a wide control range from small flow rates to large flow rates without providing a fixed orifice for detecting the pilot flow rate. .

One of the specific objects of the present invention is to be able to detect even a small amount of pilot flow and apply a displacement corresponding to the flow rate to the main valve spool, and furthermore, to It is an object of the present invention to provide a hydraulic control valve device equipped with a pilot flow rate detection mechanism that can be compactly incorporated into a system. To achieve such an object, the hydraulic control valve device of the first invention of the present application has a spool-type main valve body, which is compressed by a main valve spring from both ends within the valve body to create a spring center type, by a pilot flow. In a device that controls the flow in the main circuit using a pilot operation method by operating against the main valve spring due to the differential pressure generated before and after the pilot orifice, the main valve body is moved to the neutral position when there is no pilot pressure. and a main valve spring whose force change is equal to the main valve body displacement stroke in both directions of the main valve body displacement from the neutral position, and between the main valve body end face and the main valve spring at both ends of the main valve body. The main valve body can be displaced against the main valve spring by receiving hydraulic pressure from the pilot boat on one end side of the main valve body, and by receiving hydraulic pressure from an external boat on the other end side. At the same time, there is a pair of pilot pistons whose pressure-receiving areas for the pilot pressure are equal on both end surfaces, and the pilot piston is displaced in response to the displacement of the pilot piston directly, and is also displaced in one direction by the displacement of the pilot piston on the one end surface side due to the pilot pressure. A first main control port that allows the external boat to pass through to the supply boat when the external boat is connected to the supply boat, and a second main control port that allows the external boat to communicate with the discharge port when the pilot piston on the other end side is displaced in the other direction by the displacement due to the pilot pressure. A main valve body having a main control port symmetrically with respect to the neutral position, and an inner hole in the valve body in which the pilot piston slides is formed between the outer circumference of each pilot piston, and a first valve body that is conveyed to an external boat. The first valve chamber and the second valve chamber, which passes through the pilot boat, are shut off in the neutral state, and the first and second valve chambers are opened in each direction by the displacement of the pilot piston from the neutral position according to the pilot flow rate. A pair of pilot orifice control ports are provided that allow passage between the second valve chambers to create a constant pressure difference between the front and back, and a pair of check valves that are adapted to prevent reverse flow before and after each pilot orifice control port. It is characterized by the fact that it is equipped with

Another specific object of the present invention is to maintain the minimum operating pressure difference of the valve at a constant value without increasing even if the controlled flow rate becomes large, so that the hydraulic pressure can be controlled up to a large flow rate. An object of the present invention is to provide a control valve device.

In order to achieve such an object, the hydraulic pressure control valve device of the second invention of the present application has, in addition to the features of the first invention, the differential pressure before and after the main circuit flow control section, which is made constant according to the direction of the main flow. The main valve body is provided with a pressure compensating valve that maintains pressure so that the direction of the differential pressure before and after the main circuit flow control section applied to both ends of the pressure compensating valve is kept constant with respect to the direction of the pilot flow. The present invention is characterized in that an oil passage switching mechanism is provided for switching the oil passage for introducing pressure oil to the compensation valve.

According to the present invention, the pilot flow rate detection mechanism is configured by the pilot piston interposed between the main valve body and the main valve spring without providing an orifice in the flow path of the main control flow, and the pilot orifice of the pilot piston The opening degree of the main valve body control port can be controlled from the beginning of opening by keeping the pressure difference at the control port constant, and even if the control flow rate increases, the minimum operating pressure difference of the control valve will not increase, and the flow rate will be reduced. A single valve can be used in a wide range of control flow rates, from low to large flow rates, and with a pressure compensation valve, the pressure difference at the main valve body control port remains constant regardless of the direction of the main flow. Therefore, it is possible to always keep the pressure loss of the entire control valve below a certain value in a large flow rate case. Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the first invention, and in the hydraulic control valve device of this embodiment, a supply boat 2 is connected to a pilot boat 40 to a valve body 1, and a supply boat 2 is also connected to a pilot boat 41. A discharge boat 3 is installed, and various parts described later are installed symmetrically to the left and right when facing the same figure, centering on both the supply and discharge boats.

For convenience of explanation, parts that are installed on the left and right will be suffixed with A or C, and those that are installed on the right will be suffixed with B or D. Unless there is a change in the part name, '' will be used as the suffix for the left side configuration. Mainly detailed. That is, the spring 8A has a pressure compensating valve body 7A that slides inside the valve chamber 32A, which is suitable for the A boat 4A (B boat 4B) as an external connection boat that closes to the outside of the valve body, and is arranged in the spring chamber 26A. to form a valve chamber 22A at the back of the compensation valve body.

A main valve body 4A is disposed at both ends of the valve chamber 25A, 29A, 28A with the help of pilot pistons 13A, 13C, and a control port 2 is provided between the valve chamber 25A and the main valve body.
The valve chamber 30A, which forms the valve chambers 7A and 26A, and the valve chamber 32A and the control port 31A, passes through an internal boat 38A. The valve chamber 29A connects the main valve body at that location to the supply boat 2, the valve chamber 28A similarly connects to the discharge boat 3, and the pilot groove 46A connects the main valve body at that location to the supply boat 2. The groove 47A passes through the pilot oil passage 17A and the same passage 21A to the valve chamber 22A, and the groove 47A similarly passes through the pilot oil passage 20A and the same passage 23A to the spring chamber 24A. Main valve body 4
A pilot passage 12A is bored inside A and the groove 46 is inserted into the pilot passage 12A.
A has a pilot hole 9A, the valve chamber 25A has a pilot hole 10A, and the groove 47A has a pilot hole 11.
Shut up A. Further, a branch path is provided in the pilot passage 21A to connect it to the pilot oil passage 18A which is blocked at the neutral position of the main valve body 5A, and similarly the pilot passage 21A is
A branch path is provided at 3A and the pilot oil path 19 is installed as described above.
Connect to A. The pilot pistons 13A, 13
The other end surface of C is compressed by springs 6A and 6C disposed in the spring chambers 36A and 36C, respectively, with spring receivers interposed therebetween, and forms a valve chamber 35A that surrounds both the spring chambers 36A and 36C and both the pistons 13A and 13C. , 33A, are provided with control ports 14A and 14C that open when the piston moves toward the main valve body, and parallel to these ports is a counter-pressure that allows flow from the valve chamber side to the spring chamber side when the control ports are closed. Check valve 15
A and 15C are arranged and communicated with each other through check valve inlets 16A and 16C, and the valve chamber 35A and the valve chamber 33A are communicated with each other through a pilot passage 34A. The spring chamber 36A is connected to a pilot boat 39A provided in the valve body 1 so as to be open to the outside, and the spring chamber 36C and the A-boat 4A are connected via a pilot passage 37A. In order to describe the operation of this embodiment, the circuit of the pilot switching valve 42 shown in FIG. 1 will be explained. A is supported by the same boat 39A, and boat B is supported by the same boat 39B.

According to the above embodiment of the invention, the pilot boat 39
The pilot flow flowing in from A flows out from A boat 4A via spring chamber 36A, pilot piston control port 14A, valve chamber 35A, pilot passage 34A, valve chamber 33A, pilot piston check valve 15C, spring chamber 36C, and pilot passage 37A. However, the pilot piston 13A is displaced against the spring 6C to a position where the control row 4A has an opening degree commensurate with the pilot flow rate, and this displacement displaces the main valve body.

In the neutral state of the main valve body, the pilot oil passages 18A, 19
A is closed, pilot oil passages 17A and 20A are closed to pilot grooves 46A and 47A, and pilot holes 9A and 10 are closed.
A, 11A and the valve chamber 25 via the pilot passage 12A.
A, and depending on the displacement of the main valve body, the oil passage 17A
is closed, the oil passage 18A opens to the valve chamber 29A, and the pressure oil in the supply boat 2 is transferred from the oil passage 18A to the pilot passage 2.
1A into the valve chamber 22A, and presses the pressure compensating valve body 7A against the spring 8A to close the control port 31A. When the main valve body is further displaced, the control port 27A opens □ and the pressure oil in the valve chamber 29A flows into the valve chamber 25A, and as the oil pressure in the valve chamber increases, the oil flows into the pilot hole IA and the same passage. 12A and 6 11A and go through the same passage 23A to the spring chamber 24A.
The control port 31A is closed, and the pressure oil in the valve chamber 30A flows out to the A boat 4A via the valve chamber 32A. In this case, the pressure compensating valve body occupies a position where the pressure difference before and after the main valve body control port 27A is determined by the spring force of the spring 8A and the cross-sectional area of the compensating valve body, and the main flow of the control port 31A is controlled. control. Next, when the pilot flow is cut off, the main valve body 5A is returned to the neutral position by the spring force of the spring 6C. Contrary to the above,
Pilot flow from A boat 4A to pilot boat 3
9A, the pressure oil flows out to the boat 39A through the opposite path to that described above, and the pilot piston 13C has its control port 14C connected to the piston. The main valve body 5A is displaced against the spring 6A until it reaches a position corresponding to the flow rate, and this displacement directly displaces the main valve body 5A. In response to this main valve body displacement, the pilot oil passage 2A closes, and the oil passage 19A closes to the valve chamber 2.
8A, the pressure oil inside the compensation valve body spring chamber 24A is released to the discharge boat 3 via the pilot passage 23A, the same oil passage 20A, and the valve chamber 28A, and then the pressure oil is connected to the pilot hole 10.
A, it flows into the valve chamber 22A through the passage 12A, the hole 9A, and the passage 21A, and the compensation valve body is displaced by the hydraulic pressure against the spring 8A, thereby closing the control port 31A. When the main valve body 5A is further displaced and closes the control port 26A, the pressure oil in the valve chamber 25A flows out to the discharge boat 3 via the valve chamber 28A, and the oil pressure in the valve chamber 25A decreases. As the pressure inside the valve chamber 22A decreases as the pressure decreases, the compensating valve body is pushed back by the spring 8A and closes the control port 31A, and the pressure oil in the A boat flows out to the discharge boat 3. Similarly to the above, the pressure difference before and after the control port 26A is controlled by the pressure compensating valve body 7A, and pressure compensation is performed when controlling the flow rate of the main valve body 5A. As mentioned above, when the pilot flow flows from the pilot boat 39A to the A boat 4A, the main flow flows from the supply port 2 to the A boat 4A, and the pilot flow also flows from the A boat 4A. When the flow flows to the port 39A, the flow flows from the A boat 4A to the discharge boat 3, but before the main valve body control port 26A or 27A closes, the pilot oil passage 19A or 1
8A is closed, first the pressure compensating valve body control port 31A is temporarily closed, and then the main valve body control port 26A or 27 is closed.
A is opened and the control port 31A is opened to form the main flow, so that the jumping reduction that normally occurs in flow rate control valves does not occur. In this embodiment, since the various parts are arranged symmetrically as described above, it is needless to explain in detail that the above-mentioned operation also holds true for the right side.

The operation described above is similar to controlling the main circuit by controlling the pilot circuit, and the principle thereof will be explained as follows.

When the pilot flow rate q flows in from the pilot boat 39A, the pilot piston 13A is displaced together with the main valve body 5A against the spring 6C, and the control port 14A is opened to open the valve chamber 3.
5A, but the pressure difference Δp at the control port is determined by If the initial collapse of is Xs, the amount of overlap of the control ports is h, and the cross-sectional area of the pilot pistons 13A and 13C is AI, then △p=kl(Xs+x+h)/A
I;kl(Xs+h+)/AI, which is a substantially constant value.

The pressure difference Δpm at the control port 27A of the main valve body 5A whose pressure is compensated by the pressure compensating valve body 7A is determined by the spring constant of the spring 8A being k2, the initial operation of the spring being Xs, and the cross-sectional area of the pressure compensating valve 7A being A2, △pm=k2・Xs/A2 is constant, and since the pilot piston directly displaces the main valve body, the piston control low 4A
and the opening degree of the main valve body control port 27A are equal, and the ratio of the main flow rate Q to the pilot flow rate q is the same as that of the piston control port 14A,
The width of 14C is wl, and the equivalent width of the main valve body control ports 26A and 27A is w2 (assuming the main valve body diameter is D, w2 = mD).
Then, Q/q=(Cw2・xノ2△pm/p)/(
Cwl. x no 2 Δp/p) 3w2 no Δpm/wl no Δp =K, which is constant.

The K value in the above equation is an amplification factor, and the main flow rate Q is proportional to K times the pilot flow rate q. Therefore, the flow rate QT passing through the A or B boat is the sum of the main flow rate Q and the pilot flow rate q, which is (10K)q, and the flow rate q of the pilot circuit is proportional to the flow rate QT of the main circuit. By controlling the former circuit, the latter circuit can be controlled analogously. Furthermore, the above explanation holds true whether the flow is from the supply port to the A or B boat, or from the A or B boat to the discharge boat. Next, to further explain a usage example of the valve function according to the present invention, the circuit shown in FIG. 1 is an example of a switching valve having a single function, and the pump boat P is sent to supply boat 2 via pilot boat 40, boat A is sent to pilot boat 39A, boat B is sent to boat 39B,
As described above, the tank boat T is connected to the discharge boat 3 via the pilot boat 41. Now, when the switching valves are switched to P-A and B-T, the pilot flow on the A side is the supply boat 2, the pilot boat 40, the same switch valve 42, the boat 39A, the spring chamber 39A, and the pilot 13A. Control port 14A, valve chamber 35
A, the pilot passage 34A, the valve chamber 33A, the check valve 15C of the pilot piston 13C, the spring chamber 36C, the pilot passage 37A, and the A boat 4A flow in this order, and on the B side, it is discharged from the B boat 4B through the opposite route to the aforementioned passage. The pilot flow flowing into the boat 3 causes the main valve body 5A,
5B are displaced respectively, and the main flow is the joint boat 2 on the A side.
From there, it flows to the A boat 4A, and from the B boat 48 to the discharge boat 3 on the B side. At this time, since no other control valve is inserted in the pilot circuit, the pilot flow flows freely.
The main flow also flows freely along the aforementioned path. Also, when the switching valve is switched to A-T and P-B, the main flow is transferred from the A boat 4A to the discharge boat 3 and the supply boat 2, as described above.
It flows from there to B boat 4B. Further, FIG. 2 shows a circuit configured as a switching/flow rate control valve, and a pilot flow rate control valve 43A is installed in a pipe connecting the pilot boat 39A illustrated in FIG. 1 and the boat A of the switching valve 42. , the same flow rate control valve 43B is also inserted on the B side, and when the switching valve is switched to P-A and B-T, the pilot flow flows from the supply boat 2 on the A side to the A boat via the illustrated route. 4A, on the B side it flows from the B boat 48 to the discharge boat 3 via the illustrated path, but on the A side it is controlled to a pilot flow rate q by the pilot flow rate control valve 43A, so the flow rate of the main flow is K·q, The flow rate from the A boat 4A to the actuator is (10K)q, and since the pilot flow flows on the check valve side of the control valve 43B on the B side, the king flow also freely flows from the B boat 4B to the discharge boat 3.

When the aforementioned self-sliding valve is switched to A-T and P-B, the pilot flow on the A side freely flows to the discharge boat 3, and on the B side, it is controlled in the same manner as described above by the flow rate control valve 43B and flows to the actuator. The flow rate of is (10K)q. Since the pilot flow control valves at this time are both included in the meter, the main flow is controlled by the meter. By controlling the cut flow rate, the main flow can also be controlled meter-out. Furthermore, to further explain the circuit configuration as a switching valve and pressure reducing valve illustrated in FIG. 3, a pilot pressure reducing valve 44A is installed in the pipe line between the pilot boat 39A illustrated in FIG. 1 and the switching valve boat A as described above. When the switching valve is switched to P-A and B-T, if the pressure of the A boat 4A on the A side is lower than the pressure reducing valve set pressure, the pilot flow will flow from the supply boat 2 to the route shown in the figure. The main flow flows from the supply boat 2 to the A boat 4A according to the pilot flow rate, but when the pressure of the A boat approaches the pressure reducing valve set pressure, the pressure reducing valve flow rate decreases and the main flow The flow rate also decreases,
Since the A boat pressure is reduced to the set pressure, and on the B side, the pilot flow freely flows from the B boat 4B to the discharge boat 3 along the path shown, the king flow also flows freely from the B boat to the discharge boat 3, and When the switching valve is switched to the A-T and P-B positions, the pilot flow is free on both sides of A and B, and the king flow is also changed from the A boat 4A to the discharge boat 3.
, flows freely from supply boat 2 to B boat 48 .

Furthermore, the circuit configuration as a reef valve illustrated in FIG. 4 is similar to the pilot boat 39A shown in FIG.
, 39B and pilot relief valves 45A, 45B are arranged branching off into the respective pipelines between the forward reading switching valve boats A, B, and by switching the switching valves, the same operation as in the illustrated example of FIG. Although it operates as a switching valve, when the pressure of the A boat 4A becomes higher than the set pressure of the relief valve 45A,
Pressure oil is relieved as a pilot flow through the pilot passage 37A and other routes from the relief valve to the pilot boat 41 and then to the discharge boat 3, and the main valve body 5A is displaced by the pilot piston 13C to direct the main flow from the A boat 4A. When the pressure is relieved to the discharge boat 3 and the pressure decreases, the pilot flow stops and the main valve body 5A is returned to the neutral position by the spring force of the spring 6A, stopping the flow of reef to the discharge boat 3 and causing the flow of the reef to the discharge boat 3 to stop. The pressure is maintained at the set pressure of the relief valve 45A.

Needless to say, this operation also holds true for the B side. Furthermore, in each of the pipes between the pilot boats 39A and 39B of the pilot circuit and the boats A and B of the pilot switching valve 42 shown in FIG. In the circuit configuration shown in FIG. 5 in which the valve 43A is disposed in the latter conduit, and the relief valve 45B and the flow rate control valve 43B are disposed in the latter conduit, when the switching valve is in the neutral position, the A side is fully closed, but the B side is fully closed. 45B
operates to relieve the pressure oil in the B boat 4B to the discharge boat 3 in the same way as in the example of FIG.

When the switching valve is switched to P-A and B-T, the flow rate of the pilot circuit on the A side is adjusted to the flow rate q by the flow rate control valve 43A, so the flow rate K・q flows from the supply boat 2 to the A boat 4A. Also, when the flow rate flowing out from the A boat 4A becomes less than (10 K)q, the pressure reducing valve 44A operates to reduce the pressure of the A boat 4A to the pressure reducing valve setting pressure, and on the B side, the pilot flow flows into the B boat. 4B to flow control valve 43B
The main flow also flows freely from the B boat to the discharge boat 3 because it flows freely to the discharge boat 3 through the check valve. Next, when the switching valve is switched to A-T and P-B, the pilot flow is transferred from the A boat 4A to the pressure reducing valve 44A on the A side.
and the discharge port via each check valve of the flow control valve 43A.
Since the main flow also flows freely from the A boat 4A to the discharge boat 3, on the B side, the pilot flow is adjusted to the flow rate q by the flow rate control valve 43B and flows to the B boat 4B. The flow is from the supply boat 2 at a flow rate of K.
q flows into the B boat 4B, and its pressure is applied to the relief valve 4.
When the pressure becomes higher than the set pressure of B boat 4B, part or all of the pilot flow rate q is discharged from the relief valve 45B to the discharge boat 3, so the flow rate of the king flow also decreases and the pilot flow rate q is discharged to the discharge boat 3.
The pressure never exceeds the pressure set by the relief valve. Further, as shown in FIGS. 6 and 7 in each of the above-described embodiments, a supply port 2 and a discharge boat 3 are provided through the valve body 101, and the other valves and the valve body are laterally engaged. Support plate 10
A connection is made between the valves with a through bolt 106 and a nut 110 between the two, and A boats 4A and B are attached to the side of the valve body.
A boat 4B and a bolt hole 107 are provided to connect to the actuator, and a mounting bolt hole 108 and each pilot boat 39A, 3 are provided on the upper surface of the valve body 101 as shown in FIG.
9B, 40, 41 are standardized and the various pilot valves 42, 103, 104, 105, etc. are stacked on top of each other, or instead of the above-mentioned through-bolt fastening shown in FIG. By providing a flange 111 on the side of the valve and performing competition between the valves using short bolts 109 and nuts 110', and performing the above-mentioned configuration, an inter-valve circuit configuration may be created in which piping or manifolds are omitted. As described above, the present invention allows main flow control to be performed by retaining all the functions of the pilot circuit by configuring the pilot circuit with the pilot switching valve alone or in combination with other pilot operated valves. More specifically, a pilot circuit with the functions required for the main control circuit is constructed by combining small-capacity pilot valves with various single functions, and a small flow in the circuit is controlled from the rise of the pilot flow to a wide range. Since a large-capacity main control valve can be controlled over a control range and with a pressure compensation function depending on the direction of the main flow as necessary, a single main control valve can fulfill the same functions as the pilot circuit. The main circuit can be controlled with one type of large-capacity control valve, as the main control valve has multiple functions in one unit and can perform functions according to the functions of the pilot circuit.
All you need to do is deploy small pilot valves according to their functions.
Even when integrated as an integrated valve, it can be configured with a small number of types.
In addition, the main control valve can achieve its purpose by being integrated with the actuator stand, and is therefore small, lightweight, and inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a configuration explanatory diagram showing an embodiment of the present invention in a longitudinal side view with a pilot switching valve circuit attached, and Figs. 2, 3, 4, and 5 are longitudinal side views with other examples of pilot circuits. FIG. 6 is an explanatory diagram of the configuration shown in FIG. Fig. 7 is a front view of the previous figure, Fig. 8 is a view taken along the line A-A in Fig. 6, and Fig. 9 is another example of connection between valves, etc. FIG. 1... Valve body, 2... Supply boat, 3... Discharge boat, 4A, 4B... A, B boat, 5A, 5B... Main valve body, 7A, 7B... Pressure compensation valve body, 13A, 13B, 13C , 13D...pilot piston, 15A, 15B, 15C, 15D...check valve,
41...Pilot switching valve. Figure 6 Figure 7 Figure 1 Figure 8 Figure 2 Figure 9 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A spool-type main valve element, which has a spring center type in which main valve springs press from both ends within the valve body, is compressed by a pressure difference generated before and after a pilot orifice due to a pilot flow. In a device that operates against a spring to control the flow in the main circuit using a pilot operation method, when there is no pilot pressure, the main valve body 5A is placed in the neutral position, and the main valve body is displaced from the neutral position. Main valve springs 6A, 6C whose spring force changes with respect to the main valve body displacement stroke are equal in both directions, and interposed between the main valve body end face and the main valve springs 6A, 6C at both ends of the main valve body 5A,
Pilot port 39A on one end surface side of main valve body 5A
The main valve springs 6A and 6C can be displaced against the main valve springs 6A and 6C by receiving the hydraulic pressure from the external port 4A on both sides of the other end, and the pressure receiving area for the pilot pressure is equal on both end surfaces. a pair of pilot pistons 13A, 13C, and a pilot piston 13
A first main control port which communicates the external port 4A with the supply port 2 when it is displaced in one direction due to the displacement of the pilot piston 13A on the one end surface side due to the displacement of the pilot pressure of the pilot piston 13A on the one end side. 27A and a second main control port 26A that communicates the external port 4A with the discharge port 3 when the pilot piston 13C on the other end side is displaced in the other direction due to the displacement due to the pilot pressure, are arranged symmetrically with respect to the neutral position. The first valve chambers 35A, 36C, which are formed between the valve body hole in which the pilot pistons 13A, 13C slide and the outer periphery of each pilot piston, communicate with the external port 4A, and the pilot port. 39A and the second valve chambers 36A, 33A which are in communication with each other in the neutral state, and the first and second valve chambers 36A and 33A communicated with the first valve chamber 39A are opened in each direction according to the pilot flow rate by the displacement of the pilot pistons 13A and 13C from the neutral position. A pair of pilot orifice control ports 14A and 14C that communicate between the second valve chambers and create a constant pressure difference between the front and rear, and a pair of check valves 15A that communicate the front and rear of each pilot orifice control port against reverse flow, respectively. A hydraulic control valve device comprising: 15C. 2 Equipped with a pressure compensation valve 7A that maintains the differential pressure before and after the main circuit flow control parts 27A and 26A constant depending on the flow direction,
Further, the main valve body 5A is provided with a pressure compensating valve 7A so that the direction of the differential pressure before and after the main circuit flow control ports 27A, 26A applied to both ends of the valve is kept constant with respect to the direction of the pilot flow. Pressure oil introduction oil passages 21A and 23A to 7A
Oil passage switching mechanism 9A, 10A311A, 17A that switches
, 18A, 19A, and 20A. 18A, 19A, 20A. The hydraulic control valve device according to claim 1.