WO1995023308A1

WO1995023308A1 - Operating pressure detecting construction of pilot pressure operated type directional control valve operating device

Info

Publication number: WO1995023308A1
Application number: PCT/JP1995/000286
Authority: WO
Inventors: Toshiro Takano; Mitsumasa Akashi
Original assignee: Komatsu Ltd.
Priority date: 1994-02-24
Filing date: 1995-02-24
Publication date: 1995-08-31
Also published as: KR950025312A; JPH07239054A

Abstract

A pilot pressure operated type directional control valve operating device comprises in combination a plurality of pilot pressure operated type directional control valves each of which comprises a spool fitted in a spool bore provided in a valve body and having a plurality of ports, valve blocks each provided on both sides of the spool with a pilot pressure receiving chamber and a spring, said spool being adapted to slidably shift to a neutral position and a pressure oil supply position by the spring and an operating pressure in the pilot pressure receiving chamber. An operating pressure detecting construction of the pilot pressure operated type directional control valve operating device is such that provided in the respective valve blocks are oil holes communicating between the valve blocks, and a shuttle valve for allowing the respective oil holes to communicate with the respective pilot pressure receiving chambers, and pressure detecting means is provided in another oil hole which communicates with one of the respective oil holes.

Description

Description: Operating pressure detection structure for pilot pressure operated switching valve device

The present invention relates to a pilot-operated switching valve device that combines a plurality of pilot-pressure operated switching valves that can be switched by an operating pressure from a pilot valve. This is related to a structure for detecting the operating pressure that has occurred. Background art

For example, as shown in FIG. 1, a pilot pressure-operated switching valve is configured such that a spool 3 is inserted into a spool hole 2 formed in a valve body 1, and a cylindrical shape is formed on both end surfaces of the valve body 1. It is known that a case 4 is mounted concentrically with the spool hole 2 to form a valve block A, respectively. In the valve block A, the first and second pilot pressure receiving pressure chambers 5 and 6 are provided between both ends and each case with both ends of the spool 3 facing inside the respective cases 4. Each of them is formed, and the spool 3 is held in a neutral position by a spring 7 provided in each case 4. Then, when the operating pressure is supplied to the first or second pilot pressure receiving chamber 5 or 6, the spool 3 is slid to the first pressure oil supply position or the second pressure oil supply position. Has become.

The spool port 2 has a pump port 8, first and second reactor ports 9 and 10, first and second intermediate ports 13 and 11, and an oil port 12. And the first and second tank ports 15 and 14 respectively Is formed.

When the spool 3 is in the neutral position, the pump port 8 is disconnected from the first and second actuator ports 9 and 10, and the hydraulic port flowing into the pump port 8 is shut off. Pressure oil discharged from the pump. When the spool 3 slides to the first pressure oil supply position (the right side in FIG. 1), the pump port 8 moves through the second intermediate port 11, the oil hole 12, and the first intermediate port 13. The second pump port 10 communicates with the first pump port 9 and the second pump port 10 communicates with the second tank port 14 so that the hydraulic pump flows into the pump port 8. The discharge pressure oil flows to the first actuator port 9 to drive the actuator, and the return oil from the actuator operates the second actuator port 10. Return to the tank via. When the spool 3 slides to the second pressure oil supply position (left side in FIG. 1), the pump port 8 is moved from the first intermediate port 13, the oil hole 12, and the second intermediate port 11. The second pump port 10 communicates with the first pump port 9, the first worker port 9 communicates with the first tank port 15, and discharges from the hydraulic pump that flows into the pump port 18. The pressurized oil flows to the second actuator port 10 and drives the actuator, and the return oil from the actuator is returned to the first actuator port 9 via the first actuator port 9. To return to the tank.

FIG. 1 shows an example of a pilot-pressure-operated switching valve device that combines a plurality of these pilot-pressure-operated switching valves. This means that the valve bodies 1 of a plurality of valve blocks A are overlapped and connected so that each first tank port 15 communicates between adjacent valve blocks A, and each second tank port 15 14 also communicates between adjacent valve blocks A, and the first tanned oil flows through the oil hole 17 of the block 16 attached to one valve block A. The port 15 is connected to the second tank port 14.

In addition to the above, there is also a pilot pressure operated switching valve device in which the first and second tank ports 15 and 14 of each valve body 1 are independent.

At this point, the pilot pressure operable switching valve described above is configured such that the hydraulic pressure discharged from the hydraulic pump flowing into the pump port 8 at the neutral position is the first and second actuating ports 9, 10 Pressure, the discharge pressure of the hydraulic pump rises to the set pressure of the safety valve, etc., and becomes high.As a result, the drive horsepower of the engine that drives the hydraulic pump is wasted and the discharge pressure is reduced. The sound of the relief valve that operates the relief to release oil to the tank is loud and loud.

Therefore, conventionally, by detecting the operating pressure supplied to the first and second pilot pressure receiving portions 5 and 6 of the pilot pressure operated switching valve, the neutral position or the first and second hydraulic oils are detected. Judgment is made to the supply position, and when in the neutral position, the engine that drives the hydraulic pump is rotated at a low speed (idling rotation). (Rotation) to reduce engine drive horsepower and reduce noise when the pilot pressure operated switching valve is in the neutral position.

Then, in order to detect the above-mentioned operation pressure, for example, as shown in FIG. 2, a plurality of pilot valves 18 corresponding to each pilot pressure operation type switching valve are provided, and each pilot valve is provided. A pressure switch 21 may be provided in the first 'second output circuit 19, 20 of the shut-off valve 18, or a common switch common to both circuits 19, 20 may be provided via the shut-off valve 22. only set the pressure sweep rate pitch 2 1, to detect whether the pressure sweep rate pitch 2 1 oN, Roh me by the OFF, ⁰ Lee Lock door valve 1 8 by Ripai Lock door pressure is output, Its pressure The 〇N, OFF signal of the switch 21 is output to the engine rotation control circuit 23. When the pilot valve 18 is in the neutral state, the first and second output circuits 19 and 20 communicate with the tank.

The engine rotation control circuit 23 increases the engine speed when one of the ON and OFF signals is input from the pressure switch 21 and decreases the engine speed when the other is input. It is of the system.

However, such an operation pressure detection structure requires a large number of pressure switches 21 or a large number of shuttle valves 22 and also requires a body 24 on which these are installed, resulting in high costs. .

The present invention has been made in order to improve such a disadvantage, and it is possible to reduce the number of pressure detecting means such as a pressure switch, and to eliminate the need for a body in which a shuttle valve is installed, thereby reducing costs. In particular, an object of the present invention is to provide an operation pressure detection structure of a pilot pressure operated type switching valve device which can make the whole compact by eliminating the need for a seat valve installation place. It is.

Disclosure of the invention

In order to achieve the above object, according to one aspect of the present invention, a spool is inserted into a spool hole having a plurality of ports provided in a valve body, and a pilot pressure is placed on both ends of the spool. A chamber and a spring are respectively provided to form a valve block, and the spool is slid to a neutral position and a pressure oil supply device by the operating pressure in the spring and the pilot pressure receiving chamber. Pressure-operated switching valve operating device that combines multiple pilot-pressure operated switching valves Each of the valve blocks is provided with an oil hole communicating between the valve blocks, and a shuttle valve communicating each oil hole with each pilot pressure receiving chamber. An operation pressure detection structure for a pilot pressure operation type switching valve device, wherein pressure detection means is provided in another communicating oil hole.

According to the above configuration, the operating pressure in each pilot pressure receiving chamber flows into another oil hole communicating with each oil hole via each shuttle valve, and pressure is detected by the pressure oil flowing into the oil hole. The means is activated. Therefore, since only one pressure detecting means is required, the number of pressure detecting means can be reduced, and the cost can be reduced. Also, since each shuttle valve is provided in each block, a special body for installing each shuttle valve is not required. Therefore, the cost can be further reduced, and at the same time, since the location for installing the shuttle valve is not required, the whole can be made compact.

In addition to the above configuration, it is desirable that the other oil hole be communicated with the tank via a throttle.

Further, as a specific configuration of the operation pressure detecting structure, a cylindrical case is attached to both end surfaces of each of the valve bodies concentrically with the spool holes, and both ends of the spool face each case. A pilot pressure receiving chamber is provided between both ends and each case, a shuttle valve is provided in each case, and each valve body is overlapped and connected to communicate each oil hole. A configuration in which the other oil hole is formed in a block connected to one valve body is preferable. BRIEF DESCRIPTION OF THE FIGURES

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated in the following detailed description and attached drawings illustrating embodiments of the invention. Some aspects will be better understood. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding.

In the figure,

FIG. 1 is a longitudinal sectional view of a conventional pilot pressure operated switching valve device.

FIG. 2 is a schematic diagram of an operation pressure detecting structure applied to the above conventional example.

FIG. 3 is a plan view of a pilot pressure operation type switching valve device having an operation pressure detection structure according to the present invention.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a cross-sectional view taken along line VV of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an operation pressure detecting structure of a pilot pressure operation type switching valve device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

3 to 5 show a first embodiment of the device of the present invention. The same members as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

First and second oil holes 30 and 31 are formed near both ends in the longitudinal direction of the spool of each valve body 1. Then, a first shuttle valve 32 that communicates each first oil hole 30 with each first pilot pressure receiving chamber 5 is provided in each case 4, and each second oil hole 30 is provided in each case 4. A second shuttle valve 33 is provided in each of the other cases 4 to communicate the holes 31 with the respective second pilot pressure receiving chambers 6.

Each valve body 1 is overlapped and connected, and each first oil hole 30 is connected to the adjacent valve block. In addition to the communication between the blocks, the second oil holes 31 are also connected between the adjacent valve blocks. Then, another oil hole 34 is formed in the block 16 connected to one valve body 1, and the other oil hole 34 is formed by the first oil hole 30 and the second oil hole 3. 1 communicates with each other. Further, the oil hole 34 communicates with the tank 36 via the throttle 35, and the oil hole 34 is provided with a pressure detecting means, for example, a pressure switch 37. The switch 37 is connected to the engine rotation control circuit 23. Next, the operation of the present embodiment will be described.

First, when one pilot valve 18 is operated to output the operating pressure to the first output circuit 19, the operating pressure is supplied to the first pilot pressure receiving chamber 5 and the spool 3 is operated. Press to the right to move to the first hydraulic oil supply position.

At the same time, the operating pressure in the first pilot pressure receiving chamber 5 opens the first shuttle valve 32 and flows into the first oil hole 30, and further, the oil hole of the block 16. Flow into 3 4.

As a result, the operating pressure is introduced into the oil hole 34, and the pressure switch 37 becomes 0 N at that pressure, and outputs a 0N signal to the engine rotation control circuit 23 to output the engine signal. Since the rotation speed is increased, the discharge amount of the hydraulic pump driven by the engine increases, and a large amount of hydraulic oil is supplied from the pump port 8 to the first actuating port 9.

When the pilot valve 18 is returned to neutral from the state described above and the first output circuit 19 is connected to the tank, the pressure in the first pilot pressure receiving chamber 5 decreases and the spool 3 The spring 7 returns to the neutral position, and at the same time, the pressurized oil in the oil hole 34 of the block 16 flows out to the nozzle 36 via the throttle 35. Therefore, the pressure in oil hole 3 4 decreases, The switch 37 becomes 0FF, and the 0FF signal is input to the engine rotation control circuit 23, so that the engine rotates at low speed.

The same operation as described above is performed also when the operation pressure is output to the second output circuit 20.

Also, when the plurality of pilot valves 18 are simultaneously operated to output the operating pressure to the plurality of first output circuits 19, the operating pressure is supplied to the plurality of first pilot pressure receiving chambers 5. However, since the first oil hole 30 of each valve block A is in communication, the highest operating pressure opens the corresponding shuttle valve 32, flows into the first oil hole 30 and flows as described above. Works similarly.

That is, since the pilot valve 18 outputs a pressure proportional to the manipulated variable, when the plurality of pilot valves 18 are operated by different amounts, each of the first pilot pressure receiving chambers 5 The pressure flowing into the first oil hole 30 is different, and the higher pressure is selected by the shuttle valve 32 and flows into the first oil hole 30 as the operating pressure.

Accordingly, it is possible to cope with a case where one pilot valve 18 is operated by a small amount and the other pilot valve 18 is operated by one stroke.

The operation of the present embodiment has been described above. However, since only one pressure detection switch 21 is required, the number of pressure detection switches 21 can be reduced, and the cost can be reduced. In addition, since each shuttle valve 32 is provided in each valve block A, a special body for installing each shuttle valve 32 is not required. Therefore, the cost can be further reduced, and at the same time, the entire valve can be made compact because the installation place of the shuttle valve is not required.

In the above embodiment, the spool 3 is switched from the neutral position to the first pressure oil supply position and the second pressure oil supply position. It is needless to say that only one of the second pressure oil supply positions may be switched.

Although the present invention has been described with reference to illustrative embodiments, the disclosed embodiments do not depart from the spirit and scope of the present invention. Various modifications, omissions, and additions are possible. Is obvious to those skilled in the art. Therefore, the present invention should not be limited to the above embodiments, but should be understood to include the scope defined by the elements recited in the claims and their equivalents.

Claims

The scope of the claims

1. A spool is inserted into a spool hole having a plurality of ports provided in a valve body, and a pilot pressure receiving chamber and a spring are provided at both ends of the spool to form a valve block. A pilot in which a plurality of pilot pressure operated switching valves are provided in which a spool is slid to a neutral position and a hydraulic oil supply device by the operating pressure in the spring and the pilot pressure receiving chamber. In the pressure operated switching valve operating device,

Each of the valve blocks is provided with an oil hole communicating between the valve blocks, and a shuttle valve communicating each oil hole with each pilot pressure receiving chamber. An operating pressure detecting structure for a pilot pressure operated switching valve device, characterized in that a pressure detecting means is provided in another oil hole communicating with the other oil hole.

2. The operating pressure detecting structure for a pilot pressure operated switching valve device according to claim 1, wherein the other oil hole is connected to a tank via a throttle.

3. A cylindrical case is attached to each end face of each of the valve bodies concentrically with the spool holes, and both ends of the spool face each case, and a pyrometer is provided between the both ends and each case. A shutoff valve is provided in each case, the valve bodies are overlapped and connected to each other to communicate oil holes, and the other oil is connected to a block connected to one valve body. The operating pressure detecting structure for a pilot pressure operated switching valve device according to claim 1, wherein a hole is formed.

4. The operating pressure detecting structure for a pilot pressure operated switching valve device according to claim 3, wherein the pressure oil supply position is plural in each valve block.

5. The operating pressure detecting structure for a pilot pressure operated switching valve device according to claim 3, wherein the pressure oil supply position is one in each valve block.