JP2000220765A - Fluid switching valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically prevent a pressure drop of a hydraulic power source due to a hydraulic oil leak inevitably occurring at a switching process of a fluid switching valve by means of a switching action itself of the fluid switching valve without compensation such as driving of a hydraulic pump. SOLUTION: In a fluid switching valve 1 controlling switching of a channel by interlocking at a connectively arranged body 29 interposed between two valve elements 24 and 25 arranged facing each other and alternately opening and closing each seat parts 22 and 23 provided at both ends of a valve hole 19 by means of these valve elements 24 and 25, spools 30 and 31 switching the valve hole 19 to an open state or a blocked state while going in and out an interior of the valve hole 19 are provided at both ends of the connectively arranged body 29, and at least one of the spools 30 and 31 goes into the valve hole 19 to maintain the valve hole 19 in a blocked state during a switching process wherein both valve elements 24 and 25 open each seat parts 22 and 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid switch suitable for switching a high-pressure, large-flow hydraulic oil flow path for expanding and contracting a hydraulic cylinder for unloading and unloading cargo used in, for example, industrial machines. About the valve.

[0002]

2. Description of the Related Art Conventionally, as a fluid switching valve suitable for switching a high-pressure and large-flow hydraulic oil flow path of this type, for example, a fluid switching valve shown in FIG. The switching valve 1b is widely and generally known.

That is, a valve case 2 constituting the fluid switching valve 1b includes a supply port 7 connected to a hydraulic source 4 and a rod-side oil chamber 6 of a lift hydraulic cylinder 5 through a rod-side oil passage 3, and a bottom port. There is also a cylinder port 10 connected to the bottom oil chamber 9 of the lift hydraulic cylinder 5 through the side oil passage 8.

In addition to the supply port 7 and the cylinder port 10, the valve case 2 has a return port 13 connected to a reservoir 12 through a return oil passage 11.
And a pilot port 1 for connecting a pilot pressure chamber 14 provided at one end inside the valve case 2 to a pilot oil passage 15.
6 are provided by drilling.

The pilot oil passage 15 communicates with the hydraulic pressure source 4 through an on / off valve 17 for raising and lowering the hydraulic cylinder 5 for lift operation, and at the same time shortens the hydraulic cylinder 5 for lift operation. It is also connected to the reservoir 12 through an on / off valve 18 for lowering.

On the other hand, the valve case 2 of the fluid switching valve 1b
Is provided with a valve hole 19 extending from the supply port 7 to the return port 13 with the cylinder port 10 interposed therebetween, and through the valve hole 19, the supply port 7, the cylinder port 10, and the cylinder port 10 are provided. And return port 13
Are in communication with each other.

The opening portions at both ends of the valve hole 19 have a large-diameter valve chamber 20 communicating the supply port 7 to the valve hole 19 and a large-diameter valve chamber 21 communicating the valve hole 19 to the return port 13.
The valve hole 19 and the large-diameter valve chamber 2
The valve portions 0 and 21 form seat portions 22 and 23 on the valve hole 19 side at their respective boundary portions, and the seat portions 22 and 23 on the valve hole 19 side are accommodated inside the large diameter valve chambers 20 and 21. Opening and closing control is performed by the bodies 24 and 25, respectively.

[0008] The valve element 24 housed inside the large diameter valve chamber 20
Is urged toward the seat portion 22 on the valve hole 19 side by a piston 27 receiving an external force such as a spring means 26 or the like, and the valve body 25 accommodated in the other large-diameter valve chamber 21 has a pilot pressure. The pilot pressure is applied to the seat portion 23 on the valve hole 19 side by the pilot piston 28 which is pressed by receiving the pilot pressure in the chamber 14.

Further, between the valve bodies 24 and 25, the valve hole 1 is provided.
9 and the large-diameter valve chambers 20 and 21, a connecting member 29 b which is loosely inserted while leaving an oil passage is interposed.
7 and the pilot piston 28 press the valve bodies 24 and 25 face to face, and these valve bodies 24 and 25 are connected to the connecting body 29.
b.

Accordingly, the valve bodies 24 and 25 are integrally formed with a large diameter while expanding and contracting the spring means 26 in accordance with a pressure change in the pilot pressure chamber 14 while maintaining a predetermined interval with the interposed body 29b interposed therebetween. Each of the seat portions 2 provided at both ends of the valve hole 19 by the valve bodies 24 and 25 in conjunction with the inside of the valve chambers 20 and 21.
2, 23 will be opened and closed alternately.

Thus, when the on / off valve 17 for ascending is switched from the state shown in FIG. 5 to the "on" state,
A pilot pressure chamber 14 in the fluid switching valve 1b communicates with the hydraulic pressure source 4 from a pilot port 16 through a pilot oil passage 15 and an on / off valve 17 for ascending.

The pilot pressure in the pilot pressure chamber 14 acting on the outer end face of the pilot piston 28 by communicating the pilot pressure chamber 14 with the hydraulic pressure source 4
Spring means 26 which presses against the outer end face of
While the connecting body 29b is interposed between the valve bodies 24 and 25 between the valve body 24 and the pilot piston 28, the valve bodies 24 and 25 and the connecting body 29b are integrated and directed toward the piston 27 to be interlocked.

As a result, the valve body 24 opens the seat portion 22 on the valve hole 19 side to keep the supply port 7 and the cylinder port 10 in communication, and the valve body 25 is pressed against the seat portion 23 on the valve hole 19 side. To block communication between the cylinder port 10 and the return port 13.

Therefore, the hydraulic power source 4 is connected to the rod-side oil passage 3
To the rod-side oil chamber 6 receiving the supply pressure through
The supply port 7, the large-diameter valve chamber 20, the seat portion 22, and the valve hole 19 are also provided from the rod-side oil passage 3 to the bottom-side oil chamber 9.
The supply pressure from the hydraulic pressure source 4 acts through the cylinder port 10.

For this purpose, the lift hydraulic cylinder 5 is supplied by the hydraulic pressure source 4 acting on the rod-side oil chamber 6 and the bottom-side oil chamber 9 according to the cross-sectional area of the piston rod extending outward. The extension operation is performed due to the pressure receiving area difference between the rod-side oil chamber 6 and the bottom-side oil chamber 9.

On the other hand, conversely, if the on / off valve 18 for lowering is switched to the "on" state,
The pilot oil passage 15 communicates with the reservoir 12 so that the pilot pressure in the pilot pressure chamber
6 to the reservoir 12.

For this purpose, in this case, the piston 27
Spring means 26 overcomes the pilot pressure of the pilot pressure chamber 14 acting on the pilot piston 28, and the piston 27 and the pilot piston 28
25 and the connecting body 29b, these valve bodies 24,
25 and the connecting body 29b is pushed back to the state of FIG. 5 toward the pilot pressure chamber.

As a result, the bottom-side oil chamber 9 is connected to the cylinder port of the fluid switching valve 1b through the bottom-side oil passage 8 with respect to the rod-side oil chamber 6 of the lift hydraulic cylinder 5 to which the supply pressure from the hydraulic source 4 acts. From 10, a valve hole 19, a seat portion 23, a large-diameter valve chamber 21, a return port 13, and a return oil passage 11 communicate with the reservoir 12 through a return-side oil passage 6, which is generated between the rod-side oil chamber 6 and the bottom-side oil chamber 9. The hydraulic cylinder 5 for lift is shortened by the pressure difference.

Further, at the time of these switching operations, the on / off valve 17 for ascending and the on / off valve 18 for descending are selectively switched to "on" once, and the valve of the fluid switching valve 1b is turned on. "OFF" after switching the bodies 24 and 25
, The pilot pressure chamber 14 in the fluid switching valve 1b is kept closed to maintain the internal pilot pressure at the low pressure of the reservoir 12 or the high pressure of the hydraulic power source 4, and the valve bodies 24 and 25 are kept as they are. At the switching position.

Therefore, the on-state for ascending and descending
By using, for example, normally closed solenoid valves as the off valves 17 and 18, the hydraulic cylinder 5 for a long lift can be used.
In the case where the valve is extended and retracted over a full stroke, it is not necessary to energize the on / off valves 17 and 18 for ascending or descending for a long time, so that an energy saving effect can be obtained.

[0021]

As described above, the conventional fluid switching valve 1b has many excellent advantages as described above in terms of function, but the valve bodies 24, 25 during the switching process. Are the seat portions 22, 23 on the valve hole 19 side.
Is not closed, that is, both the seat portions 22 and 23 are opened and the rod-side oil chamber 6 and the bottom-side oil chamber 9 of the hydraulic cylinder 5 for lift are short-circuited to the reservoir 12 inevitably. .

Accordingly, especially in a fluid switching valve for switching a high-pressure, large-flow hydraulic oil flow path, a large-flow hydraulic oil instantaneously returns to the reservoir 12 and the hydraulic oil pressure of the hydraulic source 4 is increased. Decreases rapidly.

For this reason, it is necessary to drive a hydraulic pump or the like in order to compensate for the decrease in the hydraulic oil pressure of the hydraulic power source 4 as described above. As a result, there is an inconvenience such as a large power loss.

Accordingly, it is an object of the present invention to provide a hydraulic pump, which does not compensate for a pressure drop of a hydraulic power source caused by a hydraulic oil leak inevitably generated in the process of switching the fluid switching valve. An object of the present invention is to provide a fluid switching valve of this kind which can prevent power loss in advance by automatically stopping the switching operation of the fluid switching valve itself.

[0025]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell system in which two valve elements disposed opposite to each other are interlocked with each other by a connecting member interposed therebetween. In the fluid switching valve for switching the flow path by alternately opening and closing the respective seat portions provided in the valve, the valve hole is opened or closed while entering and exiting the inside of the valve hole between each valve body and the connecting body. In the middle of a switching process in which a spool for switching to the state is interposed and both of the valve bodies open their respective seat portions, at least one of the spools enters the inside of the valve hole and This is achieved by keeping the valve hole closed.

That is, by configuring as described above,
In the course of the switching process of the fluid switching valve that keeps these seats open without any of the valve bodies touching the respective seats of the valve holes, at least each of the valve bodies and the connecting body One of the spools interposed between the valve hole enters the inside of the valve hole.

With this arrangement, a short circuit between the supply port and the cylinder port of the fluid switching valve to the return port is prevented while keeping the valve hole closed by the spool, and a hydraulic pressure for compensating for a decrease in hydraulic oil pressure of the hydraulic power source. Eliminating the driving of the pump makes it possible to prevent power loss in advance.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluid switching valve 1 according to an embodiment of the present invention shown in FIG. 1 of the accompanying drawings is combined with a hydraulic drive circuit used for the above-described conventional fluid switching valve 1b. The case will be described.

In FIG. 1, the valve case 2 of the fluid switching valve 1 according to the present invention also includes a rod-side oil passage 3 through a rod-side oil passage 3 and a rod-side oil chamber 6 of a hydraulic cylinder 5 for lift.
And a cylinder port 10 connected to the bottom oil chamber 9 of the lift hydraulic cylinder 5 through the bottom oil passage 8.

The valve case 2 has a return port 13 connected to the reservoir 12 through a return oil passage 11 in addition to the supply port 7 and the cylinder port 10 described above.
And a pilot port 1 for connecting a pilot pressure chamber 14 provided at one end inside the valve case 2 to a pilot oil passage 15.
6 are provided by drilling.

The pilot oil passage 15 communicates with the hydraulic power source 4 through an on / off valve 17 for raising and lowering the hydraulic cylinder 5 for lift, and also shortens the hydraulic cylinder 5 for lift. It is also connected to the reservoir 12 through an on / off valve 18 for lowering.

On the other hand, a valve hole 19 extending from the supply port 7 to the return port 13 is provided inside the valve case 2 of the fluid switching valve 1 with the cylinder port 10 interposed therebetween.
Through the valve hole 19, the supply port 7 and the cylinder port 10, and the cylinder port 10 and the return port 1
3 are in communication with each other.

The opening portions at both ends of the valve hole 19 are provided with a large-diameter valve chamber 20 communicating the supply port 7 to the valve hole 19 and a large-diameter valve chamber 21 communicating the valve hole 19 to the return port 13.
The valve hole 19 and the large-diameter valve chamber 2
The valve portions 0 and 21 form seat portions 22 and 23 on the valve hole 19 side at their respective boundary portions, and the seat portions 22 and 23 on the valve hole 19 side are accommodated inside the large diameter valve chambers 20 and 21. Opening and closing control is performed by the bodies 24 and 25, respectively.

The valve body 2 housed inside the large diameter valve chamber 20
4 is urged by a piston 27 receiving an external force such as a spring means 26 toward the seat portion 22 on the valve hole 19 side.
The valve body 25 housed inside the other large-diameter valve chamber 21 is
The pilot pressure is applied to the seat portion 23 on the valve hole 19 side by a pilot piston 28 which is pushed by receiving the pilot pressure in the pilot pressure chamber 14.

In addition, a valve hole 1 is provided between the valve bodies 24 and 25.
9 and the large-diameter valve chambers 20 and 21, a connecting body 29 which is loosely inserted while leaving an oil passage is interposed.
And the pilot piston 28 press the valve bodies 24 and 25 against both ends of the connecting body 29.

Accordingly, the valve bodies 24 and 25 are maintained at a predetermined interval with the connecting body 29 interposed therebetween while maintaining the pilot pressure chamber 1
4, the spring means 26 is expanded and contracted in accordance with the pressure change, and the inside of the large diameter valve chambers 20 and 21 are linked together, and each of the seat portions 2 provided at both ends of the valve hole 19 by these valve bodies 24 and 25.
2, 23 will be opened and closed alternately.

The structure described above is exactly the same as that of the fluid switching valve 1b shown in FIG. 5 as a conventional example, and therefore, by switching the on / off valve 17 for ascending to "on", it is possible to use Of the hydraulic cylinder 5 for lift can be shortened by switching the on / off valve 18 for lowering to "on", and the on / off valves 17 and 18 are always used. It can be understood that by using a closed solenoid valve, the energization time can be shortened to save energy.

Nevertheless, with such a configuration, in the switching process of the fluid switching valve 1, the hydraulic oil inevitably generated when the supply port 7 and the cylinder port 10 simultaneously communicate with the return port 13. The point that the pressure drop of the hydraulic power source 4 due to the leakage must be compensated by driving the hydraulic pump or the like still remains.

Therefore, in the fluid switching valve 1 of FIG. 1 according to the embodiment of the present invention, the valve holes 19 are located at both ends of the connecting body 29 interposed between the valve bodies 24 and 25. The spools 30 and 31 serving to switch the valve hole 19 between the open state and the closed state while entering and exiting the inside of the spool are additionally provided.

Moreover, these spools 30, 31
Each of the valve bodies 24, 25 is provided with a respective seat portion 22, 2,
In the course of the switching process in which the valve 3 is not closed, at least one of them enters the inside of the valve hole 19 to keep the valve hole 19 in a closed state. And the configuration is different.

Thus, during the switching operation of the fluid switching valve 1, the valve bodies 24 and 25 are connected through the connecting body 29 until the state shown in FIG. 1 is switched to the state shown in FIG. Between the state of FIG. 3 and the state of FIG. 2 until the state of FIG. 1 is switched, the valve bodies 24 and 25 do not close any of the seat portions 22 and 23 and the supply port 7 and the cylinder port 10 are not closed. At the same time communicates with the return port 13, and a decrease in the pressure of the hydraulic power source 4 due to a hydraulic oil leak inevitably occurring with the return port 13 is prevented by the spools 30 and 31 entering the valve hole 19.

As a result, the supply port 7 and the cylinder port 10 are not short-circuited to the return port 13, so that even in a fluid switching valve for switching a high-pressure, large-flow hydraulic oil flow path, It is possible to prevent a large amount of hydraulic oil from returning to the reservoir 12 instantaneously and suddenly lowering the hydraulic oil pressure of the hydraulic power source 4.

In addition, since it is not necessary to compensate for a decrease in the operating oil pressure of the hydraulic power source 4 by a hydraulic pump or the like, power loss at that point can be eliminated.

Incidentally, in the fluid switching valve 1 according to the embodiment of the present invention, the two ends of the connecting body 29 interposed between the valve bodies 24 and 25 enter and exit the inside of the valve hole 19 at both ends. A spool 30 for opening or closing the valve hole 19,
In the course of the switching process in which both of the valve bodies 24 and 25 do not close the respective seat portions 22 and 23, at least one of the spools 30 and 31 is inserted into the valve hole 19. And the valve hole 19 is kept closed.

However, instead of doing so, each valve element 24, like the fluid switching valve 1a shown in another embodiment of FIG.
The spools 30a and 31a are provided so as to be connected to the seat surfaces 32 and 33 in the a and 25a and to switch the valve hole 19 to the open or closed state while moving in and out of the valve hole 19.

During the switching process in which each of the valve bodies 24a, 25a opens the respective seat portion 22, 23, at least the spools 30a, 31
a enters the inside of the valve hole 19 and
It is obvious without explanation that the same operation can be performed even if the device is configured to be kept closed.

Further, according to this, the valve bodies 24a,
25a, the spools 30a and 31a, and the connecting member 29a, for example, are formed integrally in advance, and then the connecting member 29a is formed.
Can be cut off from the central portion to have the same shape, thereby simplifying the structure and reducing the number of parts.

On the other hand, in the description of each embodiment according to the present invention, the hydraulic cylinder 5 for lift and the pilot pressure chamber 1 are described.
Although the same hydraulic pressure source 4 has been used as the pressure source 4, these pressure sources may be provided separately, and the fluid switching valves 1, 1 according to the present invention may be used.
The hydraulic drive circuit used in parallel with 1a is not particularly limited to the illustrated one.

[0049]

As described above, according to the first aspect of the present invention, the spool which opens and closes the valve hole while entering and leaving the inside of the valve hole between each valve element and the connecting member. And in the middle of the switching process in which neither of the two valve bodies closes the respective seat portion, at least,
One of the above-mentioned spools enters the inside of the valve hole and keeps the valve hole closed, so that the pressure of the hydraulic source caused by the hydraulic oil leak inevitably generated in the switching process of the fluid switching valve The power loss can be prevented beforehand by automatically preventing the drop by the switching operation of the fluid switching valve itself without compensating the decrease by driving the hydraulic pump or the like.

On the other hand, according to the invention of claim 2,
Spools that open or close the valve hole while entering and exiting the inside of the valve hole are provided at both ends of the continuous body, and
In the course of the switching process in which neither of the two valve bodies closes the respective seat portion, at least one of the above-mentioned spools enters the inside of the valve hole to keep the valve hole closed. With the use of a hydraulic switching valve, the pressure drop of the hydraulic source caused by the hydraulic oil leak that occurs in the switching process of the fluid switching valve is automatically prevented by the switching operation of the fluid switching valve itself without compensating by driving the hydraulic pump or the like. By doing so, power loss can be prevented beforehand.

Further, according to the third aspect of the present invention, a spool for switching the valve hole between the open state and the closed state while entering and leaving the inside of the valve hole is formed continuously with the seat surfaces of both valve bodies. In the course of the switching process in which neither of these two valve bodies closes the respective seat portion, at least one of the above-mentioned spools enters the inside of the valve hole so as to keep the valve hole closed. With this configuration, both the valve body, the spool, and the connected body are integrally formed in advance, and then the connected body is separated from the central portion to have the same shape, thereby simplifying the structure and reducing the number of parts. Reduction can also be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing a fluid switching valve according to one embodiment of the present invention in combination with a hydraulic drive circuit.

FIG. 2 is a schematic longitudinal sectional view showing a state when the fluid switching valve is in the middle of a switching process.

FIG. 3 is a schematic vertical sectional view showing a state when the fluid switching valve is completely switched.

FIG. 4 is a longitudinal sectional view schematically showing a fluid switching valve according to another embodiment of the present invention in combination with a hydraulic drive circuit.

FIG. 5 is a longitudinal sectional view schematically showing a fluid switching valve as a conventional example in combination with a hydraulic drive circuit.

[Explanation of symbols]

 1, 1a Fluid switching valve 2 Valve case 7 Supply port 10 Cylinder port 13 Return port 14 Pilot pressure chamber 16 Pilot port 19 Valve hole 20, 21 Large diameter valve chamber 22, 23 Seat portion 24, 24a, 25, 25a Valve body 26 Spring Means 27 Piston 28 Pilot Piston 29,29a Connecting Body 30,30a, 31,31a Spool 32,33 Seat Surface

Continued on the front page F term (reference) 3H056 AA08 AA09 BB01 BB32 BB50 CA01 CB03 CC02 CD02 CD06 DD03 DD10 GG12 3H067 AA16 AA17 AA24 BB03 BB12 CC32 CC41 CC60 DD05 DD33 EA01 ED15 ED20 FF11 GG15 GG22

Claims (3)

[Claims] An interlocking structure in which two valve elements disposed opposite to each other are interposed and interlocked with each other, and these valve elements alternately open and close respective seat portions provided at both ends of a valve hole. In a fluid switching valve for switching control of a flow path, a spool for switching the valve hole between open and closed states while moving in and out of the inside of the valve hole between each valve body and the connecting body is provided, and both of them are provided. In the course of the switching process in which any of the valve bodies opens the respective seat portions, at least one of the spools enters the inside of the valve hole to keep the valve hole closed. Characteristic fluid switching valve. 2. An interlocking structure in which two valve elements disposed opposite to each other are interposed and linked to each other, and these valve elements alternately open and close respective seat portions provided at both ends of a valve hole. In a fluid switching valve that controls switching of a flow path, a spool is provided for switching the valve hole to an open or closed state while moving in and out of the valve hole with respect to both ends of the continuous body, and both of the valve bodies are provided. A fluid switching valve characterized in that at least one of the spools enters into the valve hole and keeps the valve hole closed during the switching process of opening each seat portion. . 3. An interlocking structure in which two valve elements disposed opposite to each other are interposed and interlocked with each other, and the seats provided at both ends of the valve hole are alternately opened and closed by these valve elements. In a fluid switching valve for switching control of a flow path, a spool is provided in series with a seat surface of each valve body to switch the valve hole into an open or closed state while moving in and out of the valve hole, and both valves are formed. In the middle of the switching process in which each of the bodies opens the respective seat portion, at least one of the spools enters the inside of the valve hole to keep the valve hole closed. Fluid switching valve.