JPS599763B2 - Control valve operation hydraulic circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a plurality of pilot valves for one control valve, a pilot valve selection switching valve in a circuit between each pilot valve and the control valve, and a single control valve. This invention relates to an operating hydraulic circuit in which a pilot valve of a section is separably connected via a joint.

First, a conventional example of this type of operating hydraulic circuit will be explained with reference to FIG.

1 is a hydraulic power source, 2 is a control pulse 7'', and 11 is a reversible hydraulic motor controlled by the control valve.

5 and 6 are the pilot valves of the control valve 2. These control valves 7" 5.6 are connected to the common pilot pressure oil supply pipe 121 and its return pipe 122, and the pilot pipe 1 corresponding to each pilot valve is connected to the common pilot pressure oil supply pipe 121 and its return pipe 122.
02, 106 and 103.105 are connected to pilot pipes 101, 104 of the control valve 2 via pilot valve selection switching valves 3, 4.

7.8, 9.10 are joints that separate and connect the pilot valve 6 to the pilot pipe 103.105 corresponding to the valve 6, the pilot pressure oil supply pipe 121, and the return pipe 122K.

As described above, an example of an operating hydraulic circuit having two pilot valves in which one of the pilot valves 6 can be disconnected from the pilot system is as follows: There is a driver's cab each having a pilot valve at the bottom and a lower driver's cab, and during normal crane work, the upper driver's cab with the pilot valve 6 is separated and the lower driver's cab with the pilot valve 5 is operated alone.

In this operating hydraulic circuit, when the pilot valve 5 is operated, the pressure in the pilot pipe 102 or 106 increases depending on the operating direction, the spools of the switching valves 3 and 4 are switched to the a side, and the pilot pipe 101 or 10
Pressure is transmitted to 4, and the spool of control valve 2 is switched to C or d.

Furthermore, when the pilot valve 6 is operated, the pressure in the pilot pipe 103 or 105 increases depending on the operating direction, the spool of the switching valve 3.4 is switched to b, and the pressure is transmitted to the pilot pipe 101 or 104.
Switch the spool of control valve 2 to C or d in the same way as above.

In this circuit, if you disconnect the pilot valve 6 and operate it only with the pilot valve 5, do you use the joint? ,8.
9. Disconnect 10 and close the ends of pilot pipes 103 and 105.

However, with this elegance, the pilot valve 5
When operating the valve, the pressure in the pilot pipe 102 or 106 is also transmitted to the pilot pipe 103 or 105 due to internal leakage of the switching valve 3 or 4, and this pressure is transmitted between the switching valve 3 and the joint T, or between the switching valve 4 and the switching valve 4. The pilot pipe 102 is sealed in a circuit between the fitting 8 and the pilot pipe 102.
and 103, or 105 and 106 become equal, the spool of switching valve 3 or 4 does not switch completely to side a, and therefore pressure is not transmitted to pilot piping 101 or 104, resulting in malfunction of control valve 2. wake up

To prevent this, conventionally, as shown in FIG. 2, a drain pipe 110, one end of which is connected to the return pipe 122,
111, with fitting 7.8 and pilot pipe 103.1
05 are connected by hoses 12 and 12, and when the pilot valve 6 is to be disconnected, the joints 7 and 8 are connected to the drain pipes 110 and 111, respectively, thereby generating confinement pressure in the pilot pipes 103 and 105. The switching valves 3 and 4 are completely switched.

However, according to this conventional technology, it is necessary to disassemble and connect the drain pipes 110, 111 and the hose 12 using the joints 7 to 10, and the more circuits there are, the more complicated the work is and the time required for the work. become longer.

The purpose of this invention is to provide 2 {#J
To provide an operating hydraulic circuit which is equipped with the above pilot valves and has a configuration in which some of the pilot valves are separably connected by a joint, in which the work at the time of separating and connecting the pilot valves can be easily performed. be.

In order to achieve this purpose, the operating hydraulic circuit of the present invention connects piping each having a check valve to the circuit between the joint connected to the pilot valve to be separated and the switching valve, and check valve outlet side,
It is characterized in that it is connected to a drain pipe having a stop valve, and the outlet side of the drain pipe is connected to a return circuit.

An embodiment of the present invention will be described below with reference to FIG.

The embodiment shown in FIG. 3 shows an example in which two pilot valves 5.6 are installed for one control valve 2, as in the case of FIGS. 1 and 2. , the same reference numerals as in FIG. 2 indicate the same components.

This circuit is a circuit between the couplings 1, 8 connected to the pilot valve 6 to be separated and the switching valve 3.4. ．． Piping 201,2 with 21
02, and one end of the check valve outlet side of each pipe 201 and 202 is connected to the return pipe 122, and the stop valve 22
It is commonly connected to a drain pipe 203 having a.

In this circuit, pilot valve 6 is connected to joints 1 to 10.
If they are separated, the stomp valve 22 is opened.

If the stop valve 22 is opened in this way, oil that leaks from the switching valve 3 or 4 to the pilot pipe 1103 or 105 by operating the pilot valve 5 will be transferred to the pipe 201 and the check valve 20, or the pipe 202 and Pass through the check valve 21 and then drain pipe 203
, passes through the stop valve 22 and escapes to the tank 30 via the return pipe 122.

Therefore, the pilot valve 5 is connected to the pipe 103 or 105.
No confinement pressure is generated due to the switching of the switching valves 3 and 4, and switching of the switching valves 3 and 4 is performed smoothly.

On the other hand, when the pilot valve 6 is connected via the joints 7 to 10, the stop valve 22 is closed.

In this case, by operating the pilot valve 6,
For example, when the pressure in the pilot pipe 103 increases, the pressure in the pipe 201 also increases and is transmitted to the inlet side of the stop valve 22 of the drain pipe 203 through the check valve 20, but since the stop valve 22 is closed, the pressure in the return pipe 122 increases. It doesn't get across.

Further, due to the check valve 21, pressure is not transmitted to the piping 201 either.

Similarly, when the pressure in the pipe 105 increases, the change valve 20 and the stop valve 22 act to reduce the pressure in the pipe 20.
No pressure is transmitted to 1,122.

In this embodiment, an example with two pilot valves has been described, but if there are two or more pilot valves to be separated, as shown in FIG. Pipes 204 to 206 having check valves 23 to 25, respectively, are added to the corresponding pilot pipes, and the check valve outlet sides of each pipe are commonly connected to the drain pipe 203.

As described above, in the operating hydraulic circuit of the present invention, when the pilot valve is separated or connected, it is only necessary to open and close one stopper valve, and the pilot pipe is connected to the drain pipe via a joint as in the conventional case. Since the work of connecting and separating the hoses is not necessary, the work time is shortened and there is no risk of connecting the pipes incorrectly during assembly.

This effect becomes greater as the number of pilot valves to be separated increases.

In addition, in the conventional circuit, it was necessary to extend the drain pipe to the vicinity of the joint to be disassembled, but according to the present invention,
Drain piping can be connected from any position between the switching valve and the fitting, and even if there are fittings that need to be disassembled, the length and location of the piping can be selected effectively, making it easy to install the drain piping. The advantage of not being subject to the above restrictions′! J′-Yes.

Further, in the conventional circuit, there is a restriction that a hose must be connected between the switching valve and the joint, but the circuit of the present invention has the advantage of not being subject to this restriction.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional operating hydraulic circuit, Fig. 2 is a circuit diagram of a conventional operating hydraulic circuit in which the pilot valve is disassembled and a drain pipe is provided, and Fig. 3 is an implementation of the operating hydraulic circuit of the present invention. FIG. 4 is a circuit diagram showing an example in which there are a plurality of check valves to be separated in the present invention. 2...゜control valve, 3,4...switching c/1
/ 7', 5.6...Hilot Halb, T~10・
...Joint, 20.21. 23-25...Check valve, 22...Strochal 7", 101-106.
・・High lot piping, 122 ・・Return piping, 20 1
, 204-206... Piping, 203... Drain piping.

Claims (1)

[Claims] 1 A plurality of pilot valves are provided for one control valve, a switching valve for pilot valve selection is provided between each pilot valve and the control valve, and a switching valve for selecting a pilot valve is provided between some of the pilot valves and the switching valve. In an operating hydraulic circuit in which the pilot valve and the pilot pressure oil supply piping and return piping are separably connected by a joint, the switching valve is connected between the joint connected to the pilot valve to be separated and the switching valve. A pipe having a check valve was connected to each circuit, the check valve outlet side of each pipe was commonly connected to a drain pipe having a stop valve, and the outlet side of the drain pipe was connected to a pressure oil return circuit. A control valve operating hydraulic circuit characterized by: