JPS6392804A - Flushing method for hydraulic circuit - Google Patents

Abstract

PURPOSE:To enable the dirt or the like in a hydraulic circuit to be drained out without using any hydraulic device specially prepared for flushing, by fully opening a pilot check valve provided in the hydraulic circuit in a state different from the state in normal operation. CONSTITUTION:The first and the second pilot check valves 28, 29, both with relief function, are respectively connected to the first and the second delivery circuit 26, 27. The third - the sixth pilot check valves 35-38 are installed for the first directional switching-over valve 32, while the seventh - the tenth pilot check valves 41-44 are installed for the second directional switching-over valve 33. Using the above construction, the first and the second intake circuits 23, 24 and a drain circuit 31 can be flushed by fully opening the first and the second pilot check valves 28, 29. While, the first and the second delivery circuits 26, 27 and the drain circuit 31 can be flushed by fully opening the third - the tenth pilot check valves 35-38, and 41-44.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flushing method for discharging air and dirt from a hydraulic circuit in which pressure oil discharged from a hydraulic pump is supplied to hydraulic equipment through a directional control valve. It is something.

Conventional Technology If the hydraulic equipment is operated with air or dirt mixed in the circuit that makes up the hydraulic circuit, the hydraulic equipment may be damaged. In the hydraulic circuit in which the discharge circuit 2 of the pump 1 is connected to the hydraulic equipment 4 by the three-position sliding directional control valve 3, the hydraulic pump 5, the filter 6, and the discharge circuit 7 are connected as shown in FIGS. 16 to 18. and a return circuit 8, and flushing is performed using a hydraulic device exclusively for fC flushing.

Specifically, as shown in FIG. 16, the discharge circuit 7 and return circuit 8 are connected to the suction circuit 9 of the hydraulic pump 1, and the pressure oil discharged from the hydraulic pump 5 is circulated as shown by the thick line to the suction port. Road 9
Next, as shown in FIG.
1 and 12 are connected by a short-circuit path 13 and the directional control valve 3 is switched, the pressure oil discharged from the hydraulic pump 5 flows as shown by the thick line, flushing the area, and finally, as shown in Fig. 18. The entire circuit is flushed with the pressure oil discharged from the hydraulic pump 1.

Problems to be Solved by the Invention This flushing method requires a dedicated hydraulic device for brushing, resulting in high costs, and the discharge circuit 7 and return circuit 8 must be connected or separated. This makes the operation cumbersome, and since the circuit to be flushed is disassembled and bypassed, air may get in during reassembly.

Further, the hydraulic equipment 4 itself cannot be flushed, and in order to flush the hydraulic equipment 4, the hydraulic equipment must be operated, which may damage the hydraulic equipment.

Means and operation for solving the problem In a hydraulic circuit in which the discharge circuit of a hydraulic pump is connected to a hydraulic pump through a directional control valve, a pilot check valve is provided in the hydraulic circuit, and this pilot check valve is normally The pump is fully opened in a state different from the operation of the pump, allowing discharge pressure oil to flow through the publicly funded part, making it possible to discharge dust and air from the circuit without using a dedicated hydraulic device for flushing.

First and second hydraulic pumps 21.2 are installed on the output side of the embodiment engine 20.
2, and the suction port 21a of each hydraulic pump 21.22.
, 2212 in the tank 2 with the first and second suction circuits 23 and 24.
5, and the discharge ports 21b and 22.6 are connected to the first
The first and second discharge circuits 26 and 26 are connected to the second discharge circuit 26 and 27, and are connected to a drain passage 31 equipped with a filter 30 via first and second pilot check valves 28 and 29 having a relief function. .27 is the first and second directional switching valve 3
2.33 to open the first and second chambers 34a of the hydraulic equipment 34,
34b.

The first directional switching valve 32 has third to sixth pilot check valves 35 to 38 having a flow rate control function and a first directional control valve 32 which has a flow rate control function.
a second check valve 39,40;
3 are the 7th to 10th pilot check valves 41 to 44 and the first and second check valves 45, each having a flow rate control function.
゜46.

Each of the above pilot check valves is
When a pilot signal such as a gas signal is input, the valve is fully opened so that oil flows even in a direction that prevents oil flow, and each pilot signal is supplied from a controller (not shown).

Therefore, the third to tenth pilot check valves 35 to 3
8. If pilot signals are not supplied to the hydraulic equipment 34 from 41 to 44, as shown in FIG. The hydraulic equipment 34 is held in that position because the flow of pressure oil from the hydraulic equipment 34 to the drain path 31 is blocked by the fifth, sixth, ninth, and tenth pilot check valves 43 and 44. .

Furthermore, when pilot signals are supplied to the third and eighth pilot check valves 35 and 42 and the sixth and ninth pilot check valves 38 and 43, the first and second discharge circuits 26 and 27 are activated as shown in FIG. The discharge pressure oil is in the second chamber 3 of the hydraulic equipment 34.
4b and the pressure oil in the first chamber 34α flows out into the drain path 31, the hydraulic equipment 34 operates in one direction, and the
・7th pilot check valve 36.41 and 5th/1st
0 When a pilot signal is supplied to the pilot check valve 37.44, as shown in FIG. 3, the first and second discharge circuits 2
The discharge pressure oil of Nos. 6 and 27 is supplied to the first chamber 34α of the hydraulic device 34, and the pressure oil in the second chamber 34b flows out to the drain path 31, so that the hydraulic device 34 operates in the other direction.

Next, the flushing method will be sequentially explained.

As shown in FIG. 4, by supplying a pilot signal to the first and second pilot check valves 28.29 to fully open them, the discharge pressure oil of the first and second hydraulic pumps 21.22 is
- Since the oil flows from the second pilot check valve 28.29 to the drain path 31, the oil flows through the first and second suction circuits 23, 24 and the drain path 31, as shown by the bold line in Figure 4, and the oil flows through that portion. 72 tsings.

As shown in FIG. 5, the pilot signals to the first and second pilot check valves 28 and 29 are stopped, and the
By supplying a pilot signal to the pilot check valves 35 to 3g and 41 to 44 to fully open them, the pressure oil discharged from the first and second hydraulic pumps 21 and 22 becomes It flows through the two discharge circuits 26, 27 and the first and second directional valves 32, 33 to the drain passage 31 to flush that part.

As shown in FIG. 6, when a pilot signal is supplied to the fourth, fifth, eighth, and ninth pilot check valves 36, 37, 42, and 43 to fully open them, the first discharge valve is opened as shown by the solid line in FIG. The discharge pressure oil of the circuit 26 is supplied to the first chamber 34Q from the first directional switching valve 32 and flows out to the drain passage 31 from the second directional switching valve 33, and the discharge pressure oil of the second discharge circuit 27 is supplied to the first chamber 34Q from the second directional switching valve 33. It is supplied from the switching valve 33 to the second chamber 34b, flows out from the first directional switching valve 32 to the drain path 31, and is supplied to the hydraulic equipment 34.
flushing.

The above embodiment deals with the case where there is one hydraulic device, but in the case of two hydraulic devices, as shown in FIG. 7, two hydraulic devices 34.
34 may be connected in parallel with the first and second circuits 47 and 48, or as shown in FIG.
3 to the two hydraulic equipment 34 in the third to first O circuits 49 to 56
may be connected to the first and second chambers 34Q and 34b, respectively.

In addition, when there is one hydraulic pump and one hydraulic device 34, the first discharge circuit 26 of the first hydraulic pump 21 is connected to the first and second directional control valves 32 and 33, respectively, as shown in FIG. Just do it.

In addition, in the case of a hydraulic circuit equipped with a plurality of hydraulic devices and a plurality of hydraulic pumps, such as the hydraulic circuit of a power shovel, fat is a block with a directional control valve 32 in each hydraulic device 34 as shown in FIG. The pressure oil discharged from the hydraulic pump 21 may be supplied in this manner, and the discharge pressure oil may be circulated and flushed as shown by the thick lines in FIGS. 11 to 14.

Effects of the Invention By fully opening the pilot check valve in a state different from normal operation, discharge pressure oil can be circulated within the circuit to exhaust dust and air, and unlike conventional hydraulic equipment for flushing, it is not necessary. It is possible to flush and bleed air from the circuit anytime and anywhere, during on-site disassembly and assembly, or when troubleshooting, and prevents troubles in hydraulic equipment caused by dust and air.

Furthermore, since there is no need to connect or separate circuits as in the conventional case, operation is simplified, and there is no possibility that dust or air will be mixed in when the circuits are connected by mistake.

Also, in the past, after flushing the circuit,
It was necessary to connect the circuit to normal operating condition and bleed air separately, but with the present invention, flushing and air bleed can be easily performed at the same time.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram for carrying out the method according to the present invention;
6 to 6 are operation explanatory diagrams, FIGS. 7 to 9 are different hydraulic circuit diagrams, FIG. 10 is a further different hydraulic circuit diagram, and FIGS. 11 to 14 are operation explanatory diagrams, FIGS. 15 to 18 are explanatory diagrams of conventional examples.

Claims (1)

[Claims] In a hydraulic circuit in which a discharge circuit of a hydraulic pump is connected to hydraulic equipment via a directional control valve, a pilot check valve is provided in the hydraulic circuit, and the pilot check valve is fully opened in a state different from normal operation to a necessary part. A method for flushing a hydraulic circuit, characterized by circulating discharge pressure oil.