JPH0560255A - Counter balance valve - Google Patents

Abstract

PURPOSE:To facilitate processing work and provide a counter balance valve reducible in size and weight. CONSTITUTION:Between a valve body 5 and a second main passage provided on a body 1, a ring pilot passage 19 for allowing the second main passage 2 itself to communicate and the second main passage 2 to communicate with a pilot chamber 21 to a spool 7 provided in the valve body is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a counterbalance valve, and more particularly to a counterbalance valve which can be easily processed and reduced in size and weight by improving the structure of a pilot passage.

[0002]

2. Description of the Related Art A conventional counterbalance valve is constructed, for example, as shown in FIG. First, body 1
01, the body 101 has ports A and B formed therein, and ports C and D formed therein. A recess 103 is formed between the ports A and B, and the valve body 105 is inserted into the recess 103.
It is arranged. The valve body 105 has a hollow shape, and a spool 107 is accommodated therein so as to be movable in the left-right direction in the drawing. At the right end of the valve body 105 in the figure, the end plug 10
9 is attached, and the spool 107 is biased to the left side in the drawing by a coil spring 111 mounted between the spool 107 and the end plug 109. Above spool 10
A check valve 115 is arranged at the left end of FIG. 7 so as to be movable in the left-right direction in the figure. The check valve 115 is biased to the right in the figure by a coil spring 117.

The counterbalance valve having the above structure is
For example, it is used in a configuration as shown in FIG. That is, the hydraulic pump 119, the control valve 121, and the cylinder mechanism 123 as an actuator are arranged, and the counter balance valve is arranged between the control valve 121 and the cylinder mechanism 123. And the cylinder mechanism 1
When raising the piston 125 of No. 23, the control valve 1
21 is switched to the switching position 121a. As a result, the hydraulic oil supplied from the hydraulic pump 119 flows in through the port B of the counter balance valve, and moves the check valve 115 against the spring force of the coil spring 117 to open it. Then, it is supplied below the piston 125 of the cylinder mechanism 123 to raise it. At that time, the hydraulic oil returned from the cylinder mechanism 123 is returned to the tank 127 via the port C, the port D, and the control valve 121.

Next, the piston 12 of the cylinder mechanism 123
The case of lowering 5 will be described. In this case,
The control valve 121 is switched to the switching position 121b. As a result, the hydraulic oil supplied from the hydraulic pump 119 is supplied above the piston 125 of the cylinder mechanism 123 via the ports D and C, and tries to push down the piston 125. At that time, the hydraulic oil returned from the cylinder mechanism 123 is transferred to the tank 127 via the counter balance valve.
Returned to. At this time, the counter balance valve operates by the pilot pressure by the hydraulic oil supplied from the port D side.

That is, as shown in FIG.
A pilot flow passage 129 is formed in No. 1, and pilot pressure from the port D side acts on the spool 107 via this pilot flow passage 129. As a result, the spool 107 moves against the spring force of the coil spring 111, and connects the port A and the port B side. Therefore, the hydraulic oil returned from the cylinder mechanism 123 side is returned to the tank 127 via the port A, the port B, and the control valve 121, and the lowering of the piston 125 of the cylinder mechanism 123 is allowed.

[0006]

According to the above conventional structure, there are the following problems. As described above, the body 101 of the counterbalance valve has the pilot flow passage 1
29 is formed, and the pilot flow passage 129 is
It is constructed by connecting a plurality of drill holes. As described above, in order to configure the desired pilot flow passage 129, a complicated work of drilling and connecting a plurality of drill holes is required, and there is a problem that a lot of labor and a long time are required for machining. there were. In addition, in order to configure the pilot flow passage 129, the body 101 also needs to have a certain size, which causes a problem that the body 101 becomes large, and the counterbalance valve itself becomes large and heavy. there were.

The present invention has been made on the basis of such a point, and an object of the present invention is to improve the construction of the pilot passage to facilitate the working operation and to reduce the size and weight. It is to provide a counter balance valve capable of performing.

[0008]

In order to achieve the above object, a counterbalance valve according to the present invention comprises a body having a first main passage and a second main passage, and a valve body housed in the body. , When movably accommodated in the valve body and urged in one direction by an elastic member, the first main flow path is closed to move in the other direction against the urging force of the elastic member. The spool that opens the first main flow path, and the first case when the spool is movably accommodated in the spool and is moved in the other direction by an elastic member
A check valve is formed between the valve body and the second main channel, which closes the main channel and moves in one direction against the biasing force of the elastic member to open the first main channel. Second
The present invention is characterized by including an annular pilot flow passage that connects the main flow passage itself and the second main flow passage and the bylot chamber to the spool.

[0009]

First, when the working fluid is supplied from one of the first main flow paths, the check valve moves in one direction against the biasing force of the elastic member. Thereby, the first main flow path is opened and the working fluid is supplied to the actuator. that time,
The return working fluid from the actuator is returned via the second main flow path. In addition, both ends of the second main flow path are always in communication with each other through the annular pilot flow path. On the other hand, when the actuator is driven in the reverse direction, the working fluid is supplied to the actuator via the second main flow path. At that time, a part of the working fluid flowing through the second main flow passage acts on the pilot chamber through the annular pilot flow passage to move the spool in the other direction against the biasing force of the elastic member. As a result, the first main flow path is opened, and the return working fluid from the actuator is returned through the first main flow path.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. First, there is a body 1. Ports A and B are formed on the body 1, and ports C and D are formed. The ports A and B form a first main flow path, and the ports C and D form a second main flow path. A recess 3 is formed between the ports A and B and between the ports C and D, and the valve body 5 is inserted and arranged in the recess 3. The valve body 5 has a hollow shape, and a spool 7 is housed therein so as to be movable in the left-right direction in the drawing. An end plug 9 is attached to the right end of the valve body 5 in the figure, and the spool 7 is
A coil spring 11 as an elastic member mounted between the end plug 9 and the end plug 9 urges it to the left side in the drawing.
At the left end of the spool 7 in the figure, a check valve 15 is arranged so as to be movable in the left-right direction in the figure. This check valve 15
Are urged to the right in the figure by a coil spring 17 as an elastic member.

An annular pilot channel 19 is formed at the positions of the ports C and D. Further, a pilot chamber 21 is connected to the annular pilot flow passage 19, and the annular pilot flow passage 19 and the pilot chamber 2 are connected.
Pilot pressure is exerted on the spool 7 via 1.

The operation will be described based on the above configuration.
The operation will be described with reference to FIG. 3 used in the description of the conventional example. First, the cylinder mechanism 12
When the piston 125 of No. 3 is raised, the control valve 12
1 is switched to the switching position 121a. As a result, the hydraulic oil supplied from the hydraulic pump 119 flows in through the port B of the counter balance valve, and moves the check valve 15 against the spring force of the coil spring 17 to open it. Then, the piston 125 of the cylinder mechanism 123
Is supplied below and raises it. At that time, the hydraulic fluid returned from the cylinder mechanism 123 is returned to the tank 127 via the port C, the annular pilot flow passage 19, the port D, and the control valve 121.

Next, the piston 12 of the cylinder mechanism 123
The case of lowering 5 will be described. In this case,
The control valve 121 is switched to the switching position 121b. As a result, the hydraulic oil supplied from the hydraulic pump 119 is supplied above the piston 125 of the cylinder mechanism 123 via the port D, the annular pilot flow passage 19 and the port C,
It tries to push down the piston 125. At that time, the hydraulic fluid returned from the cylinder mechanism 123 is returned to the tank 127 via the counter balance valve. At this time, the counter balance valve operates by the pilot pressure by the hydraulic oil supplied from the port D side.

That is, the pilot pressure acts on the pilot chamber 21 through the annular pilot flow passage 19, whereby the spool 7 moves against the spring force of the coil spring 11, and the port A and the port B are moved. Communicate. Therefore, the hydraulic oil returned from the cylinder mechanism 123 side is returned to the tank 127 via the port A, the port B, and the control valve 121, and the lowering of the piston 125 of the cylinder mechanism 123 is allowed.

According to this embodiment, the following effects can be obtained. The pilot pressure is not applied to the spool 7 via the pilot flow passage 129 (shown in FIG. 2) formed by a complicated processing operation as in the prior art, but is applied via the annular pilot flow passage 19. Therefore, the processing of the annular pilot flow passage 19 is extremely easy, and the body 1 is not enlarged. Therefore, it is possible to facilitate the processing work, reduce the man-hours and the processing time, and reduce the weight and size. Also, port C and port D
Since it suffices that they are communicated with each other through the annular pilot flow path 19, the directing direction thereof is also free, and the flexibility in the take-out direction of the pipes (not shown) connected to the ports C and D is greatly expanded. It will be.

[0016]

As described in detail above, according to the counterbalance valve of the present invention, by improving the structure of the pilot flow passage, it is possible to reduce the number of man-hours and the time required for the machining work. It can be made smaller and lighter.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a counterbalance valve, which is a diagram showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a counterbalance valve showing a conventional example.

FIG. 3 is a circuit diagram for explaining the operation of the counterbalance valve, which is a diagram used for explaining the conventional example and the one example.

[Explanation of symbols]

 1 Body 5 Valve Body 7 Spool 11 Coil Spring (Elastic Member) 15 Check Valve 17 Coil Spring (Elastic Member) 19 Annular Pilot Flow Path 21 Pilot Chamber

Claims (1)

[Claims] 1. A body having a first main flow path and a second main flow path, a valve main body accommodated in the body, and a movably accommodated inside the valve main body provided in one direction by an elastic member. When being biased, the first main channel is closed and the spool is moved in the other direction against the biasing force of the elastic member to open the first main channel, and the spool is movable in the spool. A non-return valve that opens the first main flow path by closing the first main flow path and moving in one direction against the urging force of the elastic member when housed and moved in the other direction by the elastic member. A valve, and an annular pilot channel formed between the valve body and the second main channel for communicating the second main channel itself and for communicating the second main channel with the bilot chamber to the spool. A cow characterized by having Interbalance valve.