JPS6035567B2 - 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. In addition, as shown in Tokkoku Sho 48-73823, Tokkoku Kokai Sho 48-86121, and Tokkoku Sho 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 multifunction valves have an orifice for detecting the flow rate of the main flow in the part that controls the king flow, and the pressure difference that occurs at the orifice is fed back to the main control valve. However, 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. ,on the other hand,
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, the main valve element is inserted into the inner hole of the valve body. 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. Another specific object of the present invention is a hydraulic control valve device that can control up to a large flow rate by ensuring that the minimum operating pressure difference of the valve does not increase and remains a constant value even when the control flow rate becomes a large flow rate. The goal is to provide the following.

Yet another specific object of the present invention is to incorporate a pressure control valve inside the main valve spool to maintain a constant pressure difference before and after the main circuit control section in both directions of the main flow. The purpose is to consolidate the through holes and oil passages for the pressure compensating valve on the spool side, where there are many, to simplify the processing on the valve body side and to reduce the overall size. In order to achieve these objects, the hydraulic control valve device of the present invention uses a spool-type main valve body, which has a spring center type in which the main valve spring is pressed from both ends within the valve body, to open the pilot orifice with a pilot flow. The main valve body is operated against the main valve spring by a pressure difference generated before and after the main valve to control the flow in the main circuit by a pilot operation method, and when there is no pilot pressure, the main valve body is set to a neutral position, and A main valve spring whose spring force changes with respect to the main valve body displacement stroke in both directions of the main valve body displacement from the neutral position is the same, and a main valve spring is interposed between the main valve body end face and the main valve spring at both ends of the main valve body. One end of the main valve body receives hydraulic pressure from the pilot boat, and the other end receives hydraulic pressure from an external boat, allowing it to be displaced against the main valve spring. A pair of pilot pistons with equal pressure receiving areas for pilot pressure, and a pair of pilot pistons that are directly displaced by the displacement of the pilot piston, and when the pilot piston on one end side is displaced in one direction due to the displacement of the pilot pressure, the external port A first main control port that allows the external boat to pass through the supply boat, and a second main control port that allows the external boat to pass through the discharge boat when the pilot piston on the pond end side is displaced to the other side by the displacement due to the pilot pressure. The main valve body is arranged symmetrically with respect to the neutral position, and the pressure compensation spring chamber is arranged coaxially within the main valve body, and a pressure compensation spring chamber is formed at one end and a pressure valve chamber is formed at the other end. A main valve body includes first and second pressure compensation control ports that are biased toward the pressure valve chamber by a compensation spring and are in series with the first and second main control ports, respectively, through an internal hollow portion. A pressure compensation valve is formed between the supply boat and the pressure compensation spring chamber, and the supply boat is passed through the pressure valve chamber according to the displacement of the main valve body to one side, and the external boat is passed through the pressure compensation spring chamber, and the displacement of the main valve body to the other side. A pilot passage is bored in the main valve body to allow the external boat to pass through the pressure valve chamber and the supply boat to the pressure compensating spring chamber, and the inner hole of the valve body in which the pilot piston slides, and each pilot. A first valve chamber formed between the outer circumference of the piston and communicated with the external boat and a second valve chamber communicated with the pilot boat are cut off in the neutral state, and the pilot piston is displaced from the neutral position. A pair of pilot orifice control ports which create a constant differential pressure between the front and rear by allowing the first and second valve chambers to pass through each other at an opening degree according to the pilot flow rate in each direction, and a pair of pilot orifice control ports before and after each pilot orifice control port. It is characterized by comprising a pair of check valves, each of which allows a reverse flow to pass through.

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,
By keeping the pressure difference between the pilot orifice control port and the main valve body control port of the pilot piston constant, the relationship between each control port can be controlled from the beginning of opening, and even if the control flow rate increases, the minimum operating pressure difference of the control valve does not exceed a certain value, and a single valve can be used for a wide control flow range from small to large flow rates.In addition, a pressure compensating valve is built into the main valve body spool, making it possible to Holes and oil passages can be concentrated on the main valve body side, simplifying machining on the valve body side.

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 38 to the valve body 1, and a supply boat 2 is also connected to a pilot boat 39. A discharge boat 3 is provided, and various parts to be described later are installed symmetrically to the left and right when facing the figure, centering on both the supply and discharge boats.

For convenience of explanation, parts installed on the left side will be suffixed with A or C, and those installed on the right side will be suffixed with B or D. Unless there is a change in the part name, the description will mainly refer to the left side configuration. Explain in detail. In other words, there is no opening □ to the outside of the valve body.
A boat 4A (B boat 4) as an external connection boat
B), a valve chamber 18A that is connected to the supply boat, and a valve chamber 46A that is connected to the discharge boat 3. , 36A, and pilot pistons 33A, 33C are disposed in contact with each end face, and the other end faces of both pistons are spring receivers 44A, 44C with springs 6A, 7A disposed in spring chambers 43A, 43C, respectively. They are oppressing the government through intermediary.

The spring chamber 43A is a pilot port 3 that opens to the outside.
7A and the spring chamber 43C are connected to the A boat 4A via the pilot passage 32A. Further, the pilot pistons 33A, 33C are provided with check valve springs 4 that form the spring chambers 43A, 43C and control ports 34A, 34C, respectively.
Check valves 41A and 41C which are pressed by 2A and 42C are provided to connect the valve chambers 35A and 36A to the passages 40A and 40C.
After passing through the lotus. A sliding pressure compensating valve element 8A is inserted into the main valve element 5A, and a spring chamber 16A is formed in the main valve element 5A on one end side of the valve element, and a spring 9A is mounted thereon. A protrusion is formed on the side so that the valve can be inserted into the end wall of the valve chamber 17A between the main valve bodies. Furthermore, a valve chamber 24A that fits into the valve chamber 25A is formed in the center of the main valve body 5A, and valve chambers 27A and 20A are formed on both sides of the valve chamber 24A, and a pilot passage 12A that connects to the valve chamber 17A is bored. and insert the end hole into the valve chamber 27.
A pilot boat 14A is formed by opening in the sliding wall of the valve body 1 close to A, and branched from the passage to form the valve chamber 20.
Pilot boat 10A also opens on the sliding wall outside A.
A control row 9A is formed between the valve chambers 18A. Furthermore, a pilot passage 13A that closes to the spring chamber 16A is bored, an end hole is opened in the same sliding wall adjacent to the valve chamber 20A to form a pilot boat 11A, and a pilot boat 11A is formed by branching from the passage. A pilot boat 15A is formed outside the valve chamber 27A and similarly closes on the sliding wall, and a control port 28A is formed between the valve chambers 46A. Pressure compensation valve body 8A
Inside, a valve chamber 22A is formed in the longitudinal direction of the valve body, and a valve chamber 23A is disposed through the center, and valve chambers 26A and 21A, which are similarly disposed on both sides of the valve chamber 23A, are communicated with each other. A control port 30A is formed between the valve chamber 27A of the valve body, and a control port 29A is formed between the valve chamber 21A and the valve chamber 20A of the main valve body. In order to describe the operation of this embodiment, the circuit of the pilot switching valve 45 shown in FIG. 1 will be described.
A pilot boat 39 is connected to the tank boat T, a pilot port 37A is connected to the boat A, and a pilot port 37B is connected to the boat B.

According to the above embodiment of the invention, the pilot boat 37
The pilot flow flowing in from A passes through the spring chamber 43A, the control port 34A of the pilot piston 33A, the valve chamber 35A, the pilot passage 31A, the valve chamber 36A, the check valve 41C of the pilot piston 33C, the spring chamber 43C, and the pilot passage 32. The water flows out from the boat 4A, and the pilot piston 33A is opened by the spring 7 to an opening degree commensurate with the pilot flow rate.
A, and the main valve body 5A is displaced in accordance with the displacement.

When the main valve body is in the neutral position, pilot boat 1
0A, 11A are closed by the valve body, and both the boats open at the same time as the main valve body is displaced, but at this time, the other pilot boats 14A, 15A are blocked by the valve body, and the pilot boats 10A, 11A are closed by the valve body. When 11A is closed, the pressure oil in the supply boat 2 flows from the port 10A through the pilot passage 12A into the valve chamber 17A, pushes the pressure compensating valve body 8A against the spring 9A, and closes the control port 29A. Furthermore, when the main valve body 5A is displaced, the control row 9A opens □
When the pressure oil in the valve chamber 18A flows into the valve chamber 20A and the pressure in the valve chamber increases, the pilot boat 11A of the main valve body
Pressure oil flows into the spring chamber 16A through the passage 13A and closes the control port 29A, and the pressure oil in the valve chamber flows into the valve chamber 21A,
It flows out to A boat 4A via 22A, 23A, 24A, and 25A. In this case, the pressure compensating valve body 8A is connected to the valve chamber 18A.
and 20A to control the flow of the control port 29A by occupying a position where the pressure difference between the two is balanced with the spring force of the spring 9A and the value determined by the cross-sectional area of the compensation valve body. Next, when the pilot switching valve 45 is switched to cut off the pilot flow, the spring 7A is set so that the pilot piston connection is closed.
The main valve body 5A and the piston are displaced to maintain the neutral position, and the control row 9A is closed to cut off the main flow. Contrary to the above, when the pilot flow is flowed from the A boat 4A to the pilot boat 37A, the pressure oil in the A boat 4A flows out from the boat through a path almost reverse to that described above, and the pilot piston 33C matches the pilot flow rate. The opening degree is displaced against the spring 6A, and this displacement is applied directly to the main valve body 5A to displace the main valve body. With this displacement, the pilot boats 14A and 15A simultaneously open □, and the other pilot ports −
The ports 10A and 11A are shut off by the valve body 1. When both the boats 14A and 15A open, the boat 15A
is connected to the valve chamber 46A on the discharge boat 3 side. When the pressure oil in the compensating valve body spring chamber 16A is released to the discharge boat 3 via the pilot passage 13A, the same boat 15A, and the valve chamber 46A, it flows from the pilot boat 14A to the pilot passage 12.
A, it flows into the valve chamber 17A, and the valve chambers 25A, 24A, 2
The compensation valve body 8A is pushed against the spring 9A by the pressure oil that has flowed into the valve chamber 27A via 3A, 22A, and 26A,
The control port 30A is closed. When the control port 28A opens as the main valve body 5A is further displaced, the pressure oil in the valve chamber 27A flows out into the discharge boat 3 via the valve chamber 46A. When the oil pressure in the valve chamber 27A decreases, the compensation valve body moves into the valve chamber 1.
Due to the decrease in the oil pressure in boat 7A, it is pushed back by spring 9A to open control port 31A, and the pressure oil in boat A flows into valve chambers 25A, 24A, 23A, 22A, 26A, 27A, 4
It flows out to the discharge boat 3 through 6A and flows into the valve chambers 27A and 46A.
The pressure difference between them is constantly controlled by the compensation valve body to a value determined by the spring force of the spring 9A and the cross-sectional area of the compensation valve body, and pressure compensation is performed during flow rate control of the main valve body 5A. Thus, when the pilot flow flows from the pilot boat 37A to the A boat 4A, the royal flow flows from the supply boat 2 to the A boat 4A, and conversely, the pilot flow flows from the A boat 4A to the A boat 4A.
When flowing from A to the pilot boat 37A, the main flow flows out from the A boat 4A to the discharge boat 3. Also,
Since the pilot boat 10A or 14A closes before the control port 19A or 28A of the main valve body 5A closes, the control port 29A or 30A of the compensation valve body is closed, and then the control port 19A of the main valve body 5A closes. Or 2
8A opens, and then the control port 29A or 30A opens to allow the main flow pressure oil to flow, so that the main valve body 5A opens the control port 19A.
Also, when opening 28A, the jumping phenomenon that occurs in ordinary flow control valves does not occur. In addition, in this example,
As mentioned above, since the various parts are configured symmetrically, it is needless to explain in detail that the above-mentioned operation also holds true for the right side.

As mentioned above, the operation is to control the main circuit analogously 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 37A, the pilot piston 33A displaces together with the main valve body 5A against the spring 7A, opens the control port 34A, and flows out into the valve chamber 35A, but the pressure at the control port The difference △p is
The opening degrees of the main valve body control ports 19A, 28A and the pilot piston control ports 34A, 34C are x, the spring constants of the springs 6A, 7A are kl, the initial spring tension of the springs is Xs, and the amount of overlap of each of the control ports is h, pilot piston 33A, 33
If the cross-sectional area of C is AI, △p=kl(Xs+x10h
)/AI2kl(Xs+h)/AI, which is a substantially constant value.

The pressure difference △pm at the control port 19A of the main valve body 5A whose pressure is compensated by the pressure compensating valve body 8A is the spring constant of the spring 9A k2.
If the cross-sectional area of the pressure compensating valve 8A is A2, and the initial tension of the spring 9A is Xs, then Δpm=k2·Xs/A2, which is automatically adjusted to a constant value.

Since the pilot piston directly acts on the main valve body 5A, the relationship between the piston control port 34A and the main valve body control port 19A becomes equal, and the ratio of the main flow rate Q to the pilot flow rate q is:
The width of the pilot piston control ports 34A and 34C is wl,
If the width of the valve chambers 20A and 27A of the main valve body 5A is w2, then
Q/q=(Cw2・xノ2△pm/p)/(Cwl.x
2 Δp/p) = w2 Δpm/wl Δp =K, which is constant, and the main flow rate Q increases by the amplification factor K times in proportion to the pilot flow rate q.

Therefore, the flow rate QT passing through the A boat 4A or the B boat 4B is equal to the main flow rate Q and pi. Since it is the sum of the cut flow rate q, it becomes (10K)q, and the pilot circuit flow rate q
is proportional to the flow rate QT of the main circuit, and by controlling the former circuit, the latter circuit can be controlled analogously. The above explanation also shows that if the flow is from the supply boat to A or B boat,
This holds true in either case, from boat A or B to the discharge boat. Next, to further explain the valve function according to the present invention with reference to an example of its use, the circuit shown in FIG. As mentioned above, P is connected to the supply boat 2 via the pilot boat 38, boat A is connected to the pilot boat 37A, boat B is also connected to the piston 378, and tank boat T is connected to the discharge boat 3 via the pilot boat 39. It is as follows.

Now, when the switching valve position is switched to P-A, B-T,
On the A side, the pilot flow flows through the supply boat 2, the pilot boat 38, the switching valve 45, the pilot boat 37A, and the spring chamber 4.
3A, pilot piston control port 34A, valve chamber 35A,
Pilot passage 31A, valve chamber 36A, pilot piston check valve 41C, spring chamber 43C, pilot passage 3
2A, A boat 4A flows in that order, and B boat 4B flows on the B side.
The main flow flows from the supply boat 2 to the A boat 4A on the A side and from the B boat 4B on the B side, displacing the main valve bodies 5A and 5B respectively.
from there to the discharge boat 3. At this time, since no other control valve is inserted into the pilot circuit, the pilot flow flows freely and the main flow also flows freely along the aforementioned path. Also,
When the operating valve position is switched to A-T and P-B, the main flow flows from the A boat 4A to the discharge boat 3, and from the supply boat 2 to the B boat 4B. has a circuit configuration as a switching/flow control valve, and the pilot flow control valve 47A is placed in the pipe line between the pilot boat 37A and the boat A of the pilot switching valve 45 illustrated in FIG. The same flow control valve 47
B is inserted, and the switching valve is P-A, B-T.
, the pilot flow will flow from supply boat 2 on the A side to A boat 4A via the path shown, and on the B side to B
It flows from the boat 4B to the discharge boat 3 via the illustrated route, but on the A side, the pilot flow rate is controlled to q by the pilot flow control valve 47A, so the flow rate of the king flow is K.q, and the flow is from the supply boat 2 to the A boat. 4A, the flow rate flowing from this port to the actuator is (10K)q, and B
Since the pilot flow flows freely on the check valve side of the control valve 47B, the main flow also flows freely from the B boat 4B to the discharge boat 3.

Then, when the switching valve is switched to A-T and P-B,
On the A side, the pilot flow flows freely into the discharge boat 3;
On the B side, a flow rate of (10K)q flows to the actuator under the same control as described above with the flow rate control valve 47B. In this case, since the pilot flow control valves are both included in the meter, the main flow is controlled by the final tine, but the pilot flow rate returning to the discharge boat 3 is controlled by putting the control valve in the meter out. For example, the main flow can be controlled by metering out. Furthermore, to further explain the circuit configuration as a switching and pressure reducing valve illustrated in FIG. 3, the pilot boat 37 illustrated in FIG.
A pilot pressure reducing valve 4 is installed in the pipeline between A and the switching valve boat A.
8A is inserted, and when the pre-reading switching valve is switched to P-A and B-T, if the pressure of A port 4A on the A side is lower than the pressure reduction setting pressure, the pilot flow will be diverted from the supply boat 2. The main flow flows from the supply port 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 reduced pressure flow decreases, and the king flow rate also decreases,
The A boat pressure is reduced to the set pressure, and on the B side, the pilot flow freely flows from the B port 4B to the discharge boat 3 along the path shown in the figure, so the main flow also freely flows from the B port to the discharge boat 3. flows to

When the pilot switching valve is switched to the A-T and P-B positions,
Since the pilot flow flows freely on both sides of A and B,
The main flow also flows freely from the A boat 4A to the discharge boat 3 and from the supply boat 2 to the B boat 4B. Furthermore, the circuit configuration as a relief valve illustrated in FIG. It is equipped with valves 49A and 49B, and operates as a switching valve by switching the switching valve in the same way as the example shown in FIG. Since the oil is relieved to the discharge boat 3 through the pilot passage 32A, etc., the main valve body 5A is displaced by the pilot piston 33C, and the main flow is relieved from the A boat 4A to the discharge boat 3, and the pressure is reduced. Then, the pilot flow is stopped and the main valve body 5A is returned to the neutral position by the spring 6A, stopping the IJ leaf flow to the discharge boat 3 and maintaining the pressure of the A port 4A at the relief valve setting pressure.

Needless to say, this operation also holds true for the B side. Furthermore, in each conduit between the pilot boats 37A, 37B of the pilot circuit shown in FIG. 1 and the boats A, B of the pilot switching valve 45,
In the circuit configuration shown in FIG. 5, in which a pressure reducing valve 48A and a flow rate control valve 47A are arranged in the former pipe line, and a relief valve 49B and a flow rate control valve 47B in the latter pipe line, the A side is Although it is fully closed, the relief valve 49B on the B side operates and relieves the pressure oil from the B boat 4B to the discharge boat 3 in the same way as in the example in FIG. does not rise.

Now, when the position of the switching valve is switched to P-A and B-T, the flow rate of the pilot circuit on the A side is changed to the flow rate control valve 47A.
Since the flow rate is adjusted to q, the flow rate K·q flows from the supply boat 2 to the A boat 4A, and
When the flow rate flowing out from the port becomes less than (10K)q, the pressure reducing valve 48A 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 is controlled from the B port 4B to the flow rate. Since it flows freely to the discharge boat 3 through the check valve of valve 47B, the main flow also flows from the B port to the discharge boat 3.
Flow freely. When the switching valve is switched to A-T and P-B, the pilot flow freely flows from the A boat 4A to the discharge boat 3 after passing through the pressure reducing valve 48A and flow control valve 47A checks on the A side. The flow also flows freely from the A boat 4A to the discharge boat 3, and on the B side, the pilot flow is adjusted to the flow rate q by the flow rate control valve 47B and flows to the B boat 4B, so the main flow also flows from the supply boat 2 to the flow rate K. When q flows into the BB boat 4B and its pressure becomes higher than the set pressure of the relief valve 49B, part or all of the pilot flow q is discharged from the relief valve 49B to the discharge boat 3, so that the flow rate of the main flow is also increased. The pressure of the B boat does not exceed the relief valve set pressure. Further, as shown in FIGS. 6 and 7 in each of the above-described embodiments, a supply boat 2 and a discharge boat 3 are provided through the valve body 101, and the other valves and the valve body are laterally engaged to form a boat board. 102 through bolt 106 and nut 11
0, the A boat 4A, B boat 4B and bolt holes 107 are provided on the side of the valve body to connect to the actuator, and the mounting bolt hole 108 shown in FIG. 8 is provided on the top surface of the valve body 101. And each pilot boat 37A, 37B, 38, 39 is standardized and provided, and various pilot valves 45, 103, 104, 105... are stacked on top of each other, or the aforementioned through bolts shown in FIG. Instead of fastening, a collar 111 is provided on the side of the valve to tighten the short bolt 1.
09 and nut 11, and then perform the above-mentioned configuration to create an inter-valve circuit configuration in which piping or manifolds are omitted.

As described above, in this invention, by configuring a pilot circuit with a pilot shutoff valve alone or in combination with other pilot-operated valves, it is possible to maintain all the functions of a pilot circuit and control the main flow. , More specifically, a pilot circuit having the functions required for the main control circuit is constructed by roughly combining small-capacity pilot valves with various single functions, and the pilot flow is controlled by a small amount of flow in the circuit. Since the large-capacity main control valve can be controlled with a pressure compensation function over a wide control circuit from start-up, the main circuit can be controlled to satisfy the functions of the pilot circuit and the main control valve with a single main control valve. Since the valve has multiple functions in one unit and can perform functions according to the functions of the pilot circuit, it is only necessary to deploy small pilot valves according to the function with one type of large-capacity control valve. Even when systematizing it as a system, it can be configured with a small number of types, and the main control valve can achieve the purpose by combining it with the actuator.Furthermore, since the pressure compensation valve is incorporated into the main valve body spool, it can be configured with a small number of types. The through holes and oil passages can be concentrated on the main valve body side, simplifying the processing on the valve body side, and therefore, the valve body is 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 gate valve circuit attached, and Figs. 2, 3, 4, and 5 are longitudinal side views showing other examples of pilot circuits. The attached configuration explanatory drawings, FIG. 6 is a side view showing an example of valve connections and pilot operated valve stacking of the valve device according to the present invention, FIG. 7 is a front view of the previous figure, and FIG. 9 is a side view showing another example of the connection between valves, etc. 1... Valve body, 2... Supply boat, 3...
...Discharge boat, 4A, 4B...A, B boat, 5A,
5B... Main valve body, 8A, 8B... Pressure compensation valve body, 10A, 1OB, 11A, 1IB, 14A,
14B, 15A, 15B...Pilot boat, 19A
, 19B, 28A, 28B, 29A, 298, 30A,
30B...Control port, 33A, 33B, 33C, 33
D...Pilot piston, 45...Pilot switching valve. Figure 1 Figure 6 Figure 7 Figure 2 Figure 8 Figure 9 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 The spool-type main valve body, which is compressed by main valve springs from both ends within the valve body to create a spring center system, is operated against the main valve spring by the differential pressure generated before and after the pilot orifice due to the pilot flow. In this system, the main valve body 5A is set to the neutral position when there is no pilot pressure, and the main valve body 5A is moved in both directions when the main valve body is displaced from the neutral position. Main valve springs 6A, 7A whose spring force changes with respect to displacement stroke are equal to each other, and are interposed between the main valve body end face and the main valve springs 6A, 7A at both ends of the main valve body 5A, and one end of the main valve body 5A. Pilot port 37A on both sides
The other end side receives the hydraulic pressure from the external port 4A and can be displaced against the main valve springs 6A, 7A, and the pressure receiving area for the pilot pressure is equal on both end sides. A pair of pilot pistons 33A, 33C and a pilot piston 33
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 caused by the pilot pressure of the pilot piston 33A on the one end side. 19A and the second main control port 28A which communicates the external port 4A with the discharge port 3 when the pilot pistons 33C on both sides of the other end are displaced to the other side by the displacement due to the pilot pressure, are arranged symmetrically with respect to the neutral position. The main valve body 5A and the main valve body 5
A pressure compensating spring chamber 16 is arranged coaxially within A, and a pressure compensating spring chamber 16 is provided at one end
A is formed with a pressure valve chamber 17A on the other end side, and is spring biased toward the pressure valve chamber 17A by a pressure compensating spring 9A in the pressure compensating spring chamber, and the first and second
A pressure compensation valve 8A that forms first and second pressure compensation control ports 29A and 30A in series with the main control ports 19A and 28A, respectively, between the main valve body 5A and one of the main valve bodies 5A. According to the displacement, the supply port 2 is brought into communication with the pressure valve chamber 17A, and the external port 4A is brought into communication with the pressure compensation spring chamber 16A, and the external port 4 is brought into communication with the displacement of the main valve body 5A to the other side.
Pilot passages 12A, 13A are bored in the main valve body 5A so as to communicate the supply port 2 with the pressure valve chamber 17A and the pressure compensating spring chamber 16A, and the valves on which the pilot pistons 33A, 33C slide. When in neutral state, between the first valve chambers 35A, 43C, which are formed between the inner hole of the main body and the outer periphery of each pilot piston, and communicate with the external port 4A, and the second valve chambers 43A, 36A, which communicate with the pilot 37A. At the same time, the displacement of the pilot pistons 33A and 33C from the neutral position causes the first and second valve chambers to communicate with each other at an opening degree corresponding to the pilot flow rate in each direction, creating a constant differential pressure between the front and rear. A hydraulic control valve device comprising a pair of pilot orifice control ports 34A and 34C, and a pair of check valves 41A and 41C that communicate the front and back of each pilot orifice control port with respect to reverse flow.