JPS6238585B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to pilot operated switching valves.

Figure 1 shows a conventional pilot operated switching valve.
Two main valves 3A, 3B are pilot operated by two pilot solenoid valves 2A, 2B in the valve body 1.
are arranged in parallel, and when the three pilot solenoid valves 2A, 2B of the two main valves 3A, 3B are not energized, each main valve body 4A, 4B is lifted by the force of the springs 5A, 5B, and pilot solenoid valves 2A, 2B
When energized, each main valve element 4A, 4B closes the action chamber 6A, 6.
Due to the action force of the pilot fluid introduced into B, it is operated downward against the forces of springs 5A and 5B, and switches between the supply flow path P, load flow path A, and discharge flow path E, and one of the pilot solenoid valves malfunctions. When the two pilot electromagnetic valves 2A and 2B operate in a mismatched manner, the passages P, A, and E are connected to each other and the pressure of the fluid in the load passage A is reduced. However, when the two pilot solenoid valves 2A and 2B operate in a mismatched manner, the pressure fluid supplied to the supply channel P flows to the discharge channel E, so that the fluid in the load channel A is discharged from the discharge channel E. This has the drawback that residual pressure is generated in the fluid in the load flow path, and the fluid actuator connected to the load flow path A is likely to malfunction.

The present invention eliminates such drawbacks by preventing pressure to actuate the main valve body from being generated in the action chamber when the two pilot solenoid valves operate in a mismatched manner, thereby reliably preventing malfunction of the fluid actuator. The present invention provides a pilot operated switching valve.

For this reason, the present invention provides a valve body having a supply flow path for supplying pressure fluid, a load flow path connected to the fluid actuator, and a discharge flow path connected to the low pressure side.
Two main valve bodies equipped with a main valve body that switches and communicates between each flow path are arranged in parallel, and the pilot fluid is introduced into the action chamber formed at the end of the main valve body of each main valve. Two pilot solenoid valves are provided to operate the main valve body by discharging the pilot fluid to the low pressure side, and when the two pilot solenoid valves operate mismatched, the pilot fluid is introduced into the main valve. A communication passage is formed to discharge the pilot fluid in the chamber to the low pressure side through the pilot solenoid valve of the other main valve, and a common passageway is provided to supply pilot fluid to the two pilot solenoid valves. A throttle is provided in the pilot fluid supply path to regulate the flow rate of the pilot fluid so that pressure that operates the main valve body is not generated in the action chamber when the two pilot electromagnetic valves operate in a mismatched manner.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIGS. 2 and 3, reference numeral 9 denotes a pilot operated switching valve body (hereinafter referred to as the valve body), which is composed of a main valve body member 10 and a sub body member 16. It has a supply flow path P that supplies the fluid, a load flow path A that connects to the fluid actuator, and a discharge flow path E that connects to the low pressure side. ，
11B are formed in parallel. The sub body member 16 is provided with the fitting holes 11A and 11 of the main valve body member 10.
B is integrally arranged on the side where it opens. 12
A and 12B are main valves, which are arranged in parallel with main valve bodies 13A and 13B slidably inserted into the respective fitting holes 11A and 11B, and the main valve bodies 13A and 13B of each main valve.
B has action chambers 14A and 14B formed at the upper end,
The force of the springs 15A and 15B applied to the lower end portions act to raise the supply flow path P, respectively, and connect the load flow path A and the discharge flow path E, respectively, so as to resist the force of the springs 13A and 13B. When the lowering operation is performed, the supply flow path P and the load flow path A are communicated separately, and the discharge flow path E is separately cut off. 17A, 17
B is provided in the sub-body member 16, and includes two valve bodies 12A,
12B is a pilot solenoid valve that pilot-operates pressure lines 18A and 1 for supplying pilot fluid.
8B, pilot passages 19A, 19B communicating with the action chambers 14A, 14B, and discharge passages 20A, 20B opening to the outside on the low pressure side, and a movable iron core housed in control chambers 21A, 21B communicating with each passage. 2
2A, 22B are lowered by the force of springs 23A, 23B to block the pressure passages 18A, 18B and communicate between the pilot passages 19A, 19B and the discharge passages 20A, 20B, and by energizing the coils 24A, 24B, the movable iron cores 22A, 22B is activated to rise and the pressure path 18
A, 18B and pilot passages 19A, 19B are communicated with each other, and discharge passages 20A, 20B are blocked. 25 is a throttle, which branches from the supply flow path P and connects to the pressure path 18 of each pilot solenoid valve 17A, 17B.
Pilot fluid supply path 26 communicating with A and 18B
is provided to regulate the amount of pilot fluid supplied to the action chambers 14A, 14B. The pilot fluid supply path 26 is formed with a large diameter after the throttle 25 to form an empty space 27 so as to be filled with the pilot fluid to be introduced into the working chambers 14A and 14B.
has been established. Reference numeral 28 denotes a plate-shaped intermediate member having elasticity, which is interposed between the main body member 10 and the sub-body member 16 to prevent fluid leakage to the outside, and to prevent the notch groove 2 from leaking to the outside.
9 is provided for each main valve 12A, 12B's action chamber 14A,
A communication path 29 is formed that communicates between the sections 14B.

Next, the operation of this configuration will be explained.

Figure 2 shows two pilot solenoid valves 17A, 17.
The coils 24A and 24B are energized to operate the two pilot solenoid valves 17A and 17B.
When the matching operation is performed, the pressure passages 18A, 18B and the pilot passages 19A, 19B are communicated with each other, and the discharge passages 20A, 20B are blocked, so that the pilot fluid divided from the supply passage P to the pilot fluid supply passage 2b is divided into two. Each action chamber 14 of the main valves 12A, 12B
A, 14B, each main valve element 13A, 13B is activated by spring 15A, 15 due to the action force of the pilot fluid.
It operates downward against the force B to connect the supply flow path P and the load flow path A separately, and to cut off the discharge flow path E separately.
Further, when the coils 24A, 24B are de-energized and the two pilot solenoid valves 17A, 17B are operated in alignment, the pressure paths 18A, 18B are cut off, and the pilot paths 19A, 19B and the discharge path 20 are cut off.
A, 20B are communicated with each other to form working chambers 14A, 14B.
The pilot fluid is discharged to the outside and each main valve body 13
A and 13B are actuated upward by the force of springs 15A and 15B to respectively cut off the supply flow path P and to communicate between the load flow path A and the discharge flow path E respectively. Furthermore, a case will be described in which either one of the two pilot solenoid valves 17A, 17B breaks down due to burnout of the coils 24A, 24B, resulting in mismatched operation. Now, when the two pilot solenoid valves 17A and 17B are energized from the non-energized state and only the pilot solenoid valve 17A is activated,
The pilot fluid introduced into the working chamber 14A of the main valve 12A flows through the notched groove 29, the working chamber 14B of the main valve 12B, and is then transferred to the outside via the lower-actuated pilot solenoid valve 17B in which the pilot passage 19B and the discharge passage 20B are in communication. discharge to. Since the introduction of the pilot fluid is regulated by the throttle 25, the pressure in the action chamber 14A does not rise until the main valve element 13A is lowered, and each main valve element 13A, 13B blocks the supply flow path P and the load flow path. The fluid actuator connected to the load flow path A does not operate while being held at the original position where A and the discharge flow path E communicate with each other. Further, when the two pilot solenoid valves 17A and 17B are de-energized from the energized state and only the pilot solenoid valve 17A operates, the movable core 22A of the pilot solenoid valve 17A moves downward to cut off the pressure path 18A and open the pilot path 19A.
In order to communicate between the main valve 12B and the discharge passage 20A, the pilot fluid in the action chamber 14B of the main valve 12B flows through the notch groove 29 and the action chamber 14A to ensure normal operation of the pilot solenoid valve 1.
7A to the outside, and each main valve body 13A, 13
Since the pressure in the action chambers 14A and 14B is regulated by the action of the throttle 25, B is lowered almost simultaneously, and is raised by the force of the springs 15A and 15B, thereby blocking the supply flow path P separately. Then, the load flow path A and the discharge flow path E are communicated separately, and both are returned to their original positions and held. Therefore, the fluid in the load flow path A is easily discharged from the discharge flow path E, the pressure of the fluid in the load flow path quickly drops without generating residual pressure, and the fluid actuator is reliably stopped.

With this operation, the two pilot solenoid valves 17A,
When energizing 17B from a non-energized state to perform matching operation, the action chambers 14A, 14 of each main valve 12A, 12B
Since the pilot fluid filling the cavity 27 and the pressure passages 18A, 18B, etc. is quickly introduced into B, the main valve bodies 13A, 13B respond well without being affected by the set value of the throttle 25. .

In addition, when implementing the present invention, the main valves 12A, 12B
The main valve bodies 13A and 13B may be provided so as to communicate between the supply flow path P and the load flow path A and block the discharge flow path E at the original operating position.

In this way, the present invention provides a valve main body having a supply channel for supplying pressure fluid, a load channel connecting to a fluid actuator, and a discharge channel connecting to a low pressure side, and a main valve that switches and communicates between each channel. Two main valves with a body are arranged in parallel, and the pilot fluid is introduced into the action chamber formed at the end of the main valve body of each main valve, and the pilot fluid in the action chamber is discharged to the low pressure side. Two pilot solenoid valves are provided to operate the main valve body, and when the two pilot solenoid valves operate mismatched, the pilot fluid is introduced into the operating chamber of one of the main valves. A communication passage is formed to discharge the fluid to the low pressure side via the pilot solenoid valve of the other main valve, which is discharged to the side, and the two pilot fluids are connected to a common pilot fluid supply passage that supplies pilot fluid to the two pilot solenoid valves. By providing a restriction that regulates the flow rate of pilot fluid so that pressure that would cause the main valve body to operate does not occur in the action chamber when the two pilot solenoid valves operate mismatched, the action chamber It is possible to reliably prevent malfunction of the fluid actuator connected to the load flow path by preventing pressure from being generated to actuate the main valve body. In addition, since a restriction is provided in the common pilot fluid supply path that supplies pilot fluid to the two pilot solenoid valves to regulate the flow rate of pilot fluid supplied to the working chamber, the pilot fluid of each pilot solenoid valve is Compared to a configuration in which each throttle is provided separately in the supply channel, the configuration can be simplified and the valve can be made smaller. Furthermore, in order to improve the response of the main valve body when the two pilot solenoid valves are aligned, a pilot valve is installed after the throttle is installed. It has features such as being able to easily provide a fluid filling chamber. It has the advantage of providing good responsive operation of the main valve body.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a conventional pilot-operated switching valve, FIG. 2 is a vertical cross-sectional view of a pilot-operated switching valve showing an embodiment of the present invention, and FIG.
FIG. 1, 9... Valve body, 12A, 12B... Main valve,
13A, 13B... Main valve body, 14A, 14B...
Action chamber, 17A, 17B...Pilot solenoid valve,
29... Notch groove (communication path), P... Supply channel, A
...Load channel, E...Discharge channel.

Claims (1)

[Claims] 1. Two valve bodies each having a supply channel for supplying pressure fluid, a load channel connecting to the fluid actuator, and a discharge channel connecting to the low pressure side, and a main valve body for switching and communicating between each channel. The main valves are arranged in parallel, and the main valve body is actuated by introducing pilot fluid into the action chamber formed at the end of the main valve body of each main valve, and by discharging the pilot fluid in the action chamber to the low pressure side. Two pilot solenoid valves are provided, and when the two pilot solenoid valves operate mismatched, the pilot fluid is introduced into the working chamber of one main valve, and the pilot fluid is discharged to the low pressure side of the other main valve. A communication path is formed to discharge to the low pressure side through the pilot solenoid valve of the valve, and a common pilot fluid supply path that supplies pilot fluid to the two pilot solenoid valves acts when the two pilot solenoid valves operate in a mismatched manner. A pilot-operated switching valve that is equipped with a restriction that regulates the flow rate of pilot fluid so that no pressure is generated in the chamber to operate the main valve body.