JPH0359304B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a merging control valve used in a hydraulic control device that includes two pumps and two circuit systems connected to each pump.

(Conventional Merging Control Valve) FIG. 1 shows one circuit system, in which a plurality of directional switching valves 1 and a plurality of merging control valves 2 are provided.

When the directional control valve 1 and the merging control valve 2 are in the illustrated neutral position, their neutral passages 3 and 4 are opened, and oil from the pump 5 returns to the tank 7 through the tandem passage 6.

A parallel passage 8 is connected to the tandem passage 6 on the upstream side of the directional switching valve 1, and the other end of the parallel passage 8 is connected to the directional switching valve 1 and the merging control valve 2 beyond the directional switching valve 1. It is connected to a tandem passage 6 between the two.

The parallel passage 8 constructed as described above includes the first,
A parallel feeder 11 of the merging control valve 2 is connected between the second check valves 9 and 10.

The first check valve 9 allows only the flow from the parallel passage 8 to the parallel feeder 11, and the second check valve 10 allows only the flow from the tandem passage 6 to the parallel feeder 11. There is.

Directional switching valve 1 of the circuit system as described above
The tandem passage 6 between the merging control valve 2 and the merging control valve 2 is connected to a communication passage 12 that communicates with pumps of other circuit systems.

The specific configuration of the merging control valve 2 is as follows.
As shown in the figure.

That is, this merging control valve 2 has a valve body 13
Actuator ports 14 and 15 are formed in the spool 16, and a spool 16 is slidably provided therein.

When the spool 16 is in the neutral position shown, the tandem passage 6 and the neutral passage 4 are communicated with each other, while the actuator ports 14 and 15 are disconnected from the parallel feeder 11.

The parallel feeder 11 communicates with the parallel passage 8 via the first check valve 9, and also communicates with a communication passage 12 connected to the tandem passage 6 via the second check valve 10.

When the spool 16 is pushed to the left or right, for example, to the right in the drawing, one actuator port 14 communicates with the parallel feeder 11 via the annular groove 17 of the spool, and the other actuator port 15 communicates with a tank port 19 via an annular groove 18.

Therefore, oil from the pump flowing in from the parallel passage 8 pushes open the first check valve 9, passes through the parallel feeder 11, and flows into the actuator from the actuator port 14. Further, the return oil from this actuator flows out from the other actuator port 15 to the tank port 19.

At this time, oil from pumps in other circuit systems flows from the communication path 12 to the parallel feeder 11 via the second check valve 10.

The drawbacks of the conventional merging control valve as described above are:
The first check valve and the second check valve must be provided on opposite sides of the spool 16.

In other words, considering the configuration of these passages, it becomes necessary to provide both check valves on opposite sides as described above due to space issues.

If both check valves are installed on opposite sides like this,
Not only does the valve body become larger, but the positions of the ports associated with the check valve are also reversed, which makes machining difficult.

(Object of the present invention) An object of the present invention is to provide a merging control valve that integrally combines a first check valve and a second check valve so that the valve body does not become large due to the check valves. .

(Embodiment of the present invention) The embodiment of the present invention shown in FIG.
1 and 22, and a spool 23 is slidably provided.

The control function of the merging control valve a is exactly the same as that of the conventional valve described above, and its circuit configuration is also the same as that shown in FIG. Therefore, in explaining this embodiment, the specific configuration of the merging control valve a will be explained, and the other circuit configurations will be as shown in FIG. 1.

A connecting member 25 having a communication passage 24 is fitted to the valve body 20, and a guide pipe 26 is fitted to the connecting member 25.

The guide pipe 26 passes through a parallel feeder 27 and a parallel passage 28 formed in the valve body 20, and opens its tip opening to a tandem passage 29.

Therefore, the oil from the pump 5 that has flowed in from the tandem passage 29 and the oil from the pumps of other circuit systems are combined within this guide pipe.

A first check valve 30 and a second check valve 31 are slidably engaged with the outer periphery of the guide pipe 26 constructed as described above, and each of these check valves has the following shape. .

That is, the first check valve 30 has a poppet portion 30b formed at one end of its cylindrical portion 30a, and the second check valve 31 has a large diameter portion 31b formed at one end of its cylindrical portion 31a.

A spring 32 is interposed between the poppet portion 30b and the large diameter portion 31b, and the action of this spring 32 causes the first check valve 3
0 poppet portion 30b is normally connected to the parallel passage 2.
It is in contact with the seat portion 33 of No. 8.

The first check valve 30 configured in this manner only allows oil to flow from the parallel passage 28 to the parallel feeder 27.

Further, the second check valve 31 is normally arranged so that the large diameter portion 31b closes the through hole 34 formed in the guide pipe 26 due to the action of the spring 32.

The large diameter portion 31b that blocks the through hole 34 in this way
A gap is formed between the inner circumferential surface of the guide pipe 26 and the guide pipe 26, and this gap is used as a pressure receiving surface.

However, if the directional control valve 1 is held in the neutral position shown in FIG. 1 and the spool 23 of the merging control valve a is pushed to either the left or right, for example to the right in FIG. 43
5, 36 is cut off, and the oil from the pump 5 shown in FIG. 1 flows into the guide pipe 26.

At this time, oil from a pump in another circuit system flows from the communication passage 24 into the guide pipe 26, and the oil from both pumps merges within this guide pipe.

The oil that has merged in the guide pipe pushes open the second check valve 31 against the spring 32, flows into the parallel feeder 27 through the through hole 34, and from this parallel feeder 27 flows into one actuator port. 21 into the actuator.

Further, the return oil from the actuator returns to the tank from the other actuator port 22 via the tank port 37.

Furthermore, when the directional control valve 1 is switched to either the left or right side, the oil supply to the tandem passage 29 is cut off, but the oil from the pump 5 is transferred to the parallel passage 2.
8, the first check valve 30 is pushed open, and the water flows out from one actuator port 21 via the parallel feeder 27. Further, the oil from the communication passage 24 pushes open the second check valve 31, flows into the parallel feeder 27, and joins with the oil from the pump 5.

Note that even when the spool 23 is pulled to the left in the drawing in the opposite manner to the above, the merging relationship is the same as above.

(Structure of the present invention) This invention forms a pair of actuator ports in a valve body, and a spool is slidably provided in the valve body, and when the spool is held at a neutral position, a tandem passage and a neutral flow are formed. connected with the road,
When the spool is switched to either position, communication between the tandem passage and the neutral passage is cut off, while
In a merging control valve configured such that a parallel passage and a parallel feeder communicate with each other via a check valve, a communication passage for introducing oil from a pump in another circuit system is formed in the valve body, and the communication passage and A guide pipe is provided that directly communicates with the tandem passage, and a first check valve and a second check valve are slidably engaged with the guide pipe, and the first check valve connects the parallel passage to the parallel feeder. The major feature is that the second check valve only allows flow from inside the guide pipe to the parallel feeder.

With the above configuration, oil from other circuit systems can be merged from the communication path via the guide pipe.

(Effects of the present invention) As described above, the present invention provides the first
Since the check valve and the second check valve are slidably engaged, both check valves can be integrated into one side of the spool.

Since both check valves can be integrated as described above, the valve body can be made smaller compared to conventional control valves, and ports related to the check valves only need to be formed in one place. ,
Processing of the valve body also becomes easier.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram, FIG. 2 is a sectional view of a conventional merging control valve, and FIG. 3 is a sectional view of the present invention. 20... Valve body, 21, 22... Actuator port, 23... Spool, 24... Communication passage, 26... Guide pipe, 27... Parallel feeder, 28... Parallel passage, 29... Tandem passage, 30... First check valve, 31...Second check valve.

Claims (1)

[Claims] 1 A pair of actuator ports are formed in the valve body, and a spool is slidably provided in the valve body, and when the spool is held in a neutral position,
When the tandem passage and the neutral passage communicate with each other and the spool is switched to either position, the communication between the tandem passage and the neutral passage is cut off, while the parallel passage and the parallel feeder communicate with each other through the check valve. In the merging control valve configured to communicate, a communication passage is formed in the valve body to introduce oil from a pump of another circuit system, and a guide pipe is provided to directly communicate the communication passage with the tandem passage, A first check valve and a second check valve are slidably engaged with the guide pipe, the first check valve only allowing flow from the parallel passage to the parallel feeder, and the second check valve connecting the guide pipe to the parallel feeder. A merging control valve configured to only allow flow from inside to the parallel feeder.