JPH058324Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fluid control device that controls the operation of a fluid actuator by pilot operating four poppet-type main valves.

[Prior art]

As one of this type of fluid control device,
The device shown in FIG. 4 is proposed in Japanese Patent No. 57002. The fluid control device shown in FIG.
Controls each communication between the inflow path P and the first load path A, between the inflow path P and the second load B, between the outflow path R and the first load A, and between the outflow path R and the second load B. poppet-type main valves 1 to 4, and each of these main valves 1 to 4
For example, when the opening degree of the main valves 1 and 2 can be adjusted using adjustment screws (not shown), the inflow is made such that the differential pressure across the throttle remains constant. A pressure control valve 6 has a function of controlling the pressure in the passage P, that is, a pressure compensation function, and a pilot pressure ( (Leaded from each load path A, B)
The inflow path P is connected to the fluid pump 8, both the load paths A and B are connected to the actuator 9, and the outflow path R and the discharge path DR are connected to the actuator 9.
is connected to the tank 10.

In such a fluid control device, by setting the pilot valve 5 to the state shown in the figure, all the main valves 1 to
4 is closed to maintain the pressure in both load paths A and B, and at the same time, the selection valve 7 is turned on as shown in the figure to open the fluid pump 8.
By operating the pilot valve 5, the main valves 1, 4 or 2, 3 are opened and the actuator 9 is actuated in one direction (or the other), and at the same time, the selection valve 7 is actuated to unload the load path. It is possible to control the pressure in the inflow path P according to the pressure in the load path A or B by guiding the pilot pressure from A or B to the pressure control valve 6.

[Problem that the invention attempts to solve]

In the conventional fluid control device described above, since the main valves 1 to 4 are poppet-type valves, when all the main valves 1 to 4 are closed with the pilot valve 5 in the state shown in the figure, the main valves 1 to 4 are closed. Although the selection valve 7 is not shown in the figure, the selection valve 7 is not shown in the diagram. Although it is not a spool-type valve, the pilot pressure introduced from the load paths A and B is always applied to the pilot pressure inlets 7a and 7b.
It may be difficult to reduce leakage into the discharge path DR at the selection valve 7, and the above-mentioned holding function may not be ensured satisfactorily.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and is intended to be applied to devices such as the conventional fluid control device described above, that is, between the inflow path and the first load path, between the inflow path and the second load path, and between the outflow path. 4 which controls each communication between the first load path and between the outflow path and the second load path, respectively.
a poppet-type main valve, a pilot valve for controlling the operation of each of the main valves, a pressure compensation valve provided so that the differential pressure across the throttle formed by the main valve is constant; In a fluid control device comprising a spool-type selection valve that is operated by fluid pressure applied from a pilot valve to switch the pilot pressure applied to the pressure compensation valve, a pilot pressure introduction path to the selection valve is provided. A feature of the present invention is that the selection valve includes a poppet-type normally closed valve that opens when a switching operation is performed to connect the pilot pressure introduction path only to the pressure compensation valve.

[Functions and effects of the idea]

In the fluid control device according to the present invention, the poppet-type normally-closed valve is closed except when the selection valve connects the pilot pressure introduction path, in which the poppet-type normally-closed valve is interposed, only to the pressure compensating valve. There should be almost no leakage through the pressure introduction channel. Therefore, the pressure holding function obtained by closing the four poppet-type main valves can be better ensured than in the past.

〔Example〕

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

The fluid control device according to the present invention shown in FIG.
Controls communication between inflow path P and first load path A, between inflow path P and second load path B, between outflow path R and first load path A, and between outflow path R and second load path B. 4 poppet-type main valves 11 to 14 (adjusting screw 11
The flow rate can be adjusted by a to 14a)
, a pilot valve 15 that controls the operation of each of the main valves 11 to 14, and a pilot valve 15 that controls the operation of the inflow path P according to pilot pressure applied from a selection valve 17, which is interposed between the inflow path P and the outflow path R and will be described later. The pressure control valve 16 controls the pressure of the inflow path P, each load path A,
It is provided with a selection valve 17 for switching the pilot pressure led from B, as well as a pilot switching valve 21 and a pilot opening/closing valve 22. The configuration and functions of the main valves 11 to 14, the pilot valve 15, and the pressure control valve 16 are the same as those of the main valves 1 to 4, the pilot valve 5, and the pressure control valve 6 of the conventional device shown in FIG. The functions are the same, and like the conventional device, the inflow path P is connected to the fluid pump 18, and both load paths A and B are connected to the actuator 19.
An outflow path R and a discharge path DR are connected to the tank 20.

The selection valve 17 is in the neutral position shown when the pilot valve 15 is in the neutral position shown, and connects the pilot pressure introduction path P1 led out from the inflow path P to the pilot pressure supply path V1 leading to the pressure control valve 16,
In addition, the pilot pressure introduction path B1 leading to the pilot on-off valve 22 is communicated with the discharge path DR, and the load path A is also connected to the exhaust path DR.
The pilot pressure introduction path A1 led out from the pilot pressure supply path V1 is cut off from the pilot pressure supply path V1 and the like. This selection valve 17 is operated by the pilot pressure applied through the pilot path PA when the solenoid a of the pilot valve 15 is energized, and the pilot pressure introduction path P1, the pilot pressure supply path V1, and the pilot pressure introduction path B1 are operated. and the discharge passage DR are cut off, and the pilot pressure introduction passage A1 communicates with the pilot pressure supply passage V1, and also by the pilot pressure applied through the pilot passage PB when the solenoid b of the pilot valve 15 is energized. The pilot pressure introduction path P1 and the pilot pressure supply path V1 are disconnected from each other, and the pilot pressure introduction path B1 is disconnected from the discharge path DR and communicated with the pilot pressure supply path V1. .

The pilot switching valve 21 is actuated by the pilot pressure applied through the pilot passage PB at the same time that the solenoid b of the pilot valve 15 is energized and the selection valve 17 is switched. The pilot pressure supplied through the pilot pressure introduction path P1 derived from P is supplied to the pilot on-off valve 22. The pilot opening/closing valve 22 is a poppet type normally closed valve, and is operated by the pilot pressure when it is supplied from the pilot pressure introduction path P1 via the pilot switching valve 21. At times, the pilot pressure introduction passage B2 led out from the load passage B communicates with the pilot pressure introduction passage B1 so that the pressure in the load passage B is guided to the selection valve 17, and when the valve is not in operation as shown, the pilot pressure introduction passage B1 is connected to the pilot pressure introduction passage B1. The communication between B2 and B2 is completely cut off.

In the fluid control device of this embodiment configured as described above, the solenoid b of the pilot valve 15 is energized to open the main valves 12 and 13, and the selection valve 17 is connected so that the pilot pressure supply path V1 is connected to the pilot pressure introduction path B1. A pilot on-off valve 22 is opened when the two are operated to communicate with each other, and at other times the pilot on-off valve 22 is closed to completely shut off communication between pilot pressure introducing paths B1 and B2. Therefore, the holding function obtained by closing the four main valves 11 to 14 when the pilot valve 15 is at the neutral position shown in the figure is better ensured than in the conventional device shown in FIG. I can do it. In addition, in the fluid control device of this embodiment, since nothing is interposed in the pilot pressure introduction path A1,
When the four main valves 11 to 14 are closed, there is a risk of fluid leaking from the pilot pressure introduction passage A1 to the discharge passage DR, but if this becomes a problem, the fluid may leak from the pilot pressure introduction passage A1. A poppet-type normally closed valve similar to the pilot on-off valve 22 may also be installed. Further, in this embodiment, the pilot opening/closing valve 22 is opened by the pilot pressure supplied from the pilot pressure introduction path P1 via the pilot switching valve 21. It is also possible to operate the pilot on-off valve 22 to open simultaneously with the switching operation of the selection valve 17 by the pilot pressure supplied through the PB.

2 and 3 show an embodiment in which a pressure control valve 24 is interposed in the outflow path R to function as a meter-out pressure compensation valve, and in this embodiment, a selection valve 25, a pilot Switching valve 2
6. A pilot on-off valve 27 is adopted. Although other configurations are not shown, they are the same as the embodiment shown in FIG.

As shown in FIGS. 2 and 3, the selection valve 25 includes a spool valve body 25a, a pair of annular plates 25b, 25c, and a pair of springs 25d, 25.
e, and when the pilot valve 15 is in the neutral position as shown, the spool valve body 25a etc. are in the neutral position as shown, and the pilot pressure introduction path B1 leading to the pilot opening/closing valve 27 is connected to the pilot pressure supply path leading to the pressure control valve 24. A pilot pressure introduction path A that communicates with the exhaust path DR together with V1 and is led out from the load path A.
1 from the pilot pressure supply path V1, etc. In this selection valve 25, the pilot valve 1
When solenoid a of No. 5 is energized, the pilot path
The spool valve body 25a is actuated against the spring 25d by the pilot pressure applied through PA, so that the pilot pressure supply path V1 is cut off from the discharge path DR and communicates only with the pilot pressure introduction path B1. When the solenoid b of the bypass valve 15 is energized, the spool valve body 25a operates against the spring 25e by the pilot pressure applied through the pilot passage PB, and the pilot pressure introduction passage B1, the pilot pressure supply passage V1, and the pilot Communication between the pressure supply path V1 and the discharge path DR is cut off, and the pilot pressure introduction path A1 communicates with the pilot pressure supply path V1.

The pilot switching valve 26 is actuated by the pilot pressure applied through the pilot passage PA at the same time that the solenoid a of the pilot valve 15 is energized and the selection valve 25 is switched. The pilot pressure supplied through the pilot pressure introduction path P1 derived from P is supplied to the pilot on-off valve 27. The pilot opening/closing valve 27 is a poppet type normally closed valve, and is operated by the pilot pressure when it is supplied from the pilot pressure introduction path P1 via the pilot switching valve 26. At times, the pilot pressure introduction passage B2 led out from the load passage B communicates with the pilot pressure introduction passage B1 so that the pressure in the load passage B is guided to the selection valve 25, and when the valve is not in operation as shown, the pilot pressure introduction passage B1 is connected to the pilot pressure introduction passage B1. The communication between B2 and B2 is completely cut off.

It should be noted that the functions and effects obtained by this embodiment will be easily understood from the above-mentioned configuration and the explanation given in the embodiment shown in FIG. 1, so a description thereof will be omitted.

In each of the above embodiments, the present invention was implemented in a fluid control device equipped with the main valves 11 to 14 and the pilot valve 15 shown in FIG. The fluid control device proposed by the present applicant in Application No. 61-31701 can be implemented in the same manner or with appropriate modifications.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a fluid control device according to the present invention with some symbols shown, Fig. 2 is a diagram showing a modification of the part shown in Fig. 1 with symbols, and Fig. FIG. 4 is a detailed sectional view of the selection valve shown in FIG. 4, and FIG. 4 is a diagram showing a conventional example. Explanation of symbols, 11 to 14...Poppet type main valve,
15... Pilot valve, 16, 24... Pressure control valve (pressure compensation valve), 17, 25... Spool type selection valve, 21, 26... Pilot switching valve, 22,
27... Pilot on-off valve (poppet type normally closed valve),
P... Inflow path, R... Outflow path, A, B... Load path, DR... Discharge path, B1, B2... Pilot pressure introduction path.

Claims (1)

[Scope of utility model registration request] Four poppet-type main valves each control communication between the inflow path and the first load path, between the inflow path and the second load path, between the outflow path and the first load path, and between the outflow path and the second load path. , a pilot valve that controls the operation of each of these main valves, a pressure compensation valve provided so that the differential pressure across the throttle formed by the main valve is constant, and a pressure applied from the pilot valve. A fluid control device comprising a spool-type selection valve operated by fluid pressure to switch the pilot pressure applied to the pressure compensating valve, wherein the selection valve is connected to a pilot pressure introduction path to the selection valve. 1. A fluid control device comprising a poppet-type normally closed valve that opens when a switching operation is performed to connect a pressure introduction path only to the pressure compensation valve.