JP2552836B2 - Hydraulic circuit flushing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flushing device for discharging air and dust in a hydraulic circuit in which hydraulic oil discharged from a hydraulic pump is supplied to a hydraulic device by a directional control valve. It is a thing.

2. Description of the Related Art If hydraulic equipment is operated in a state where air or dust is mixed in the hydraulic circuit, the hydraulic equipment may be damaged. For example, as shown in FIG. In the hydraulic circuit in which 2 is connected to the hydraulic device 4 by the three-position slide type directional control valve 3, as shown in FIGS. 16 to 18, the hydraulic pump 5, the filter 6 and the discharge circuit 7 are provided.
Flushing is performed by using a hydraulic system dedicated to flushing, which is provided with a return circuit 8.

Specifically, as shown in FIG. 16, the discharge circuit 7 and the return circuit 8 are connected to the suction circuit 9 of the hydraulic pump 1 so that the discharge pressure oil of the hydraulic pump 5 is circulated as indicated by the thick line to suck the suction circuit. 9
Then, as shown in FIG. 17, the discharge circuit 7 and the return circuit 8 are connected to the discharge circuit 2 of the hydraulic pump 1 and the drain path 10, and the outlet circuits 11 and 12 of the directional control valve 3 are connected.
Is connected by a short-circuit path 13 and the directional control valve 3 is switched so that the pressure oil discharged from the hydraulic pump 5 flows as shown by a thick line to flush that portion, and finally as shown in FIG. The entire circuit is flushed with the discharge pressure oil of 1.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention Such a flushing method requires a hydraulic system dedicated to flushing, resulting in high cost, and connecting or disconnecting the discharge circuit 7 and the return circuit 8 thereof. Therefore, the operation becomes troublesome, and the circuit to be flushed is disassembled and bypassed, so that air may enter 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 Actions for Solving Problems] In the present invention, the discharge passage of the hydraulic pump, the drain circuit and the first chamber 34a and the second chamber 34b of the hydraulic device 34 are switched to the first directional switching valve 32 and the second directional switching. A first pilot check that connects and disconnects by a valve 33, blocks the first directional switching valve 32 from flowing the oil from the discharge passage toward the first chamber 34a, and circulates the oil in the above direction by a pilot signal. Valve and
A second pilot check that blocks the flow of oil from the discharge passage in the direction of the second chamber 34b and the flow of oil in the direction by a pilot signal, and blocks the flow of oil from the first chamber 34a to the drain circuit. And a third pilot check valve that allows oil to flow in the direction by the pilot signal, and a fourth pilot check valve that prevents oil from flowing from the second chamber 34b to the drain circuit and that allows oil to flow in the direction by the pilot signal. The pilot check valve is provided between the first pilot check valve and the first chamber 34a, and the first chamber 34a to the first chamber 34a
Check valve for preventing oil from flowing to the pilot check valve of the second check valve, the second pilot check valve and the second check valve, and
The second check valve is provided between the second chamber 34b and the second chamber 34b to prevent the oil from flowing from the second chamber 34b to the second pilot check valve. A fifth pilot check valve that blocks the oil flow in the direction of the first chamber 34a and that allows the oil to flow in the direction according to a pilot signal;
A sixth pilot check that blocks the flow of oil from the discharge passage in the direction of the second chamber 34b and the flow of oil in the above direction by a pilot signal, and blocks the flow of oil from the first chamber 34a to the drain circuit. And a seventh pilot check valve for circulating oil in the direction according to the pilot signal, and an eighth pilot check valve for blocking the circulation of oil from the second chamber 34b to the drain circuit and circulating oil in the direction by the pilot signal. The pilot check valve is provided between the fifth pilot check valve and the first chamber 34a, and is provided between the first chamber 34a and the fifth chamber.
Third check valve for preventing oil from flowing to the pilot check valve, the sixth pilot check valve, and the second check valve
A fourth check valve is provided between the second chamber 34b and the sixth pilot check valve to prevent the oil from flowing from the second chamber 34b, and the oil from the discharge passage of the hydraulic pump toward the drain circuit is formed. Is a flushing device for a hydraulic circuit, which is provided with a ninth pilot check valve that blocks the flow of oil in the direction described above and that allows oil to flow in the direction according to a pilot signal.

As a result, when the ninth pilot check valve is set in a state in which oil flows in accordance with the pilot signal, the discharge pressure oil of the hydraulic pump flows from the discharge passage to the drain circuit, so that the discharge passage can be flushed.

Further, when the first to eighth pilot check valves are brought into a state in which the oil is circulated by the pilot signal, the hydraulic fluid discharged from the hydraulic pump circulates inside the first and second directional control valves 32, 33 to the drain circuit. Because it flows out, the first and second directional control valves
32,33 The inside can be flushed.

Further, if the first and fourth pilot check valves of the first directional switching valve 32 and the sixth and seventh pilot check valves of the second directional switching valve 33 are brought into a state in which oil flows according to the pilot signal, the hydraulic pump The discharge pressure oil is the first chamber of the hydraulic device 34.
Since it flows through 34a and the second chamber 34b to the drain circuit,
The first chamber 34a and the second chamber 34b of the hydraulic device 34 can be flushed.

Example The first and second hydraulic pumps 21 and 22 are connected to the output side of the engine 20, and the suction ports 21a and 22a of the respective hydraulic pumps 21 and 22 are connected to the tank 25 by the first and second suction circuits 23 and 24. Connect and discharge port 2
1b and 22b are first and second pilot check valves 28 and 2 which are connected to the first and second discharge circuits 26 and 27 and have a relief function.
Connect via 9 to the drain path 31 with the filter 30,
The first and second discharge circuits 26, 27 are the first and second directional control valves 32, 33.
It is connected to the first and second chambers 34a and 34b of the hydraulic device 34 via.

The first directional control valve 32 includes third to sixth pilot check valves 35 to 38 having a flow rate control function, and first and second pilot check valves 35 to 38.
The second directional control valve 33 includes check valves 39 and 40, and the second directional control valve 33 includes seventh to tenth pilot check valves 41 to 44 and first and second check valves 45 and 46 having a flow rate control function.

Each of the pilot check valves is fully opened to allow the oil to flow even in the direction of blocking the oil flow when a pilot signal such as a pilot fluid or electric signal is input, and each pilot signal is supplied from a controller (not shown). is there.

Then, set the 3rd-10th pilot valve to 35-3.
If pilot signals are not supplied to 8,41 to 44, as shown in FIG. 1, pressure oil is supplied to the hydraulic equipment 34 by the third, fourth and seventh and eighth pilot check valves 35,36 and 41,42. Is blocked and the flow of pressure oil from the hydraulic device 34 to the drain passage 31 is blocked by the fifth, sixth and ninth and tenth pilot check valves 43, 44, so that the hydraulic device 34 is held in that position. .

Further, when a pilot signal is supplied to the third and eighth pilot check valves 35 and 42 and the sixth and ninth pilot check valves 38 and 43, as shown in FIG.
26, 27 discharge pressure oil is supplied to the second chamber 34b of the hydraulic device 34,
Moreover, the pressure oil in the first chamber 34a flows out to the drain passage 31, the hydraulic device 34 operates in one direction, and the fourth and seventh bi-lock check valves 36, 41 and the fifth and tenth pilot check valves 37, When a pilot signal is supplied to 44, as shown in FIG.
The discharge pressure oil of the second discharge circuits 26, 27 is the first chamber 3 of the hydraulic device 34.
4a, and the pressure oil in the second chamber 34b is drained to the drain passage 31.
And the hydraulic device 34 operates in the other direction.

 Next, the flushing method will be sequentially described.

As shown in FIG. 4, the first and second pilot checkers
By supplying a pilot signal to 28 and 29 to fully open,
The pressure oil discharged from the first and second hydraulic pumps 21 and 22 flows from the first and second pilot check valves 28 and 29 to the drain passage 31, so that the first and second suction circuits 23 as shown by the thick lines in FIG. ,twenty four
The oil circulates through the drain passage 31 and the drain passage 31, and the portion is flushed.

As shown in FIG. 5, the pilot signals to the first and second pilot check valves 28 and 29 are stopped, and the pilot signals to the third to tenth pilot check valves 35 to 38 and 41 to 44 are fully opened. As shown by the thick line in FIG.
The discharge pressure oil of the second hydraulic pumps 21,22 flows through the first and second discharge circuits 26,27 and the first and second directional control valves 32,33 to the drain passage 31, and the portion is flushed. To do.

As shown in FIG. 6, when a pilot signal is supplied to the fourth, fifth, eighth and ninth pilot check valves 36, 37, 42, 43 to fully open, the first discharge as shown by the solid line in FIG. Circuit 26
Of the discharge pressure oil is supplied from the first direction switching valve 32 to the first chamber 34a, flows out from the second direction switching valve 33 to the drain passage 31, and the discharge pressure oil of the second discharge circuit 27 is discharged into the second direction switching valve. From 33rd room
It is supplied to 34b and flows out to the drain path 31 from the 1st directional control valve 32, and flushes the hydraulic equipment 34.

In the above embodiment, there is one hydraulic device, but when there are two hydraulic devices, as shown in FIG.
May be connected in parallel with the first and second circuits 47 and 48, and
As shown in the figure, the first and second directional control valves 32, 33 are set to the third to the first.
The first and second chambers 34a and 34b of the two hydraulic devices 34 are connected by the 0 circuits 49 to 56.
You may connect to each.

When there is one hydraulic pump and one hydraulic device 34, as shown in FIG. 9, the first discharge circuit of the first hydraulic pump 21.
26 may be connected to the first and second directional control valves 32 and 33, respectively.

Further, in the case of a hydraulic circuit including a plurality of hydraulic devices and a plurality of hydraulic pumps, such as a hydraulic circuit of a power shovel, for example, as shown in FIG.
The discharge pressure oil of the hydraulic pump 21 may be supplied via 32, 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 When the ninth pilot check valve is set in a state in which oil flows according to a pilot signal, the discharge pressure oil of the hydraulic pump flows from the discharge passage to the drain circuit, so that the discharge passage can be flushed.

Further, when the first to eighth pilot check valves are brought into a state in which the oil is circulated by the pilot signal, the hydraulic fluid discharged from the hydraulic pump circulates inside the first and second directional control valves 32, 33 to the drain circuit. Because it flows out, the first and second directional control valves
32,33 The inside can be flushed.

Further, if the first and fourth pilot check valves of the first directional switching valve 32 and the sixth and seventh pilot check valves of the second directional switching valve 33 are brought into a state in which oil flows according to the pilot signal, the hydraulic pump The discharge pressure oil is the first chamber of the hydraulic device 34.
Since it flows through 34a and the second chamber 34b to the drain circuit,
The first chamber 34a and the second chamber 34b of the hydraulic device 34 can be flushed.

In addition, since the first to ninth pilot check valves can be flushed by setting the oil to flow in accordance with the pilot signal, there is no need for a dedicated hydraulic device for flushing as in the conventional case. ,or,
It is possible to flush the circuit and bleed air anytime and anywhere when repairing a trouble, and prevent troubles of hydraulic equipment due to dust and air.

Further, since it is not necessary to connect or separate the circuit as in the conventional case, the operation is simple, and dust and air are not accidentally mixed in when the circuit is connected.

Further, in the past, after flushing the inside of the circuit, it was necessary to connect the circuit to a normal operating state and separately perform air bleeding, but in the present invention, flushing and air bleeding can be performed simultaneously and easily. It became possible to practice.

[Brief description of drawings]

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

Claims (1)

(57) [Claims] 1. A first directional switching valve 32 and a second directional switching valve 33 connect and disconnect the discharge path of the hydraulic pump, the drain circuit and the first chamber 34a and the second chamber 34b of the hydraulic device 34, respectively, The direction switching valve 32 includes a first pilot check valve that blocks the flow of oil from the discharge passage in the direction of the first chamber 34a and that allows oil to flow in the above direction in response to a pilot signal, and the direction of the discharge chamber from the second chamber 34b. A second pilot check that blocks the flow of oil to the direction of the oil by the pilot signal and the oil flow from the first chamber 34a to the drain circuit, and moves in the direction of the pilot signal by the pilot signal. A third pilot check valve that distributes oil and a second
Provided between the first pilot check valve and a fourth pilot check valve that blocks oil flow from the chamber 34b to the drain circuit and that allows oil to flow in the direction according to a pilot signal, and the first chamber 34a. A first check valve for preventing oil from flowing from the first chamber 34a to the first pilot check valve, the second pilot check valve, and the second chamber
A second check valve that is provided between the second chamber 34b and the second pilot check valve and blocks the flow of oil from the second chamber 34b to the second pilot check valve. A fifth pilot check valve that blocks the flow of oil in the direction of the chamber 34a and that flows in the direction by a pilot signal, and blocks the flow of oil in the direction of the second chamber 34b from the discharge passage, A sixth pilot check valve for circulating oil in the direction according to the signal, and a seventh pilot check valve for blocking oil circulation from the first chamber 34a to the drain circuit and circulating oil in the direction by the pilot signal. , Second
Provided between the eighth pilot check valve, which blocks the oil flow from the chamber 34b to the drain circuit and which allows the oil to flow in the direction in accordance with the pilot signal, and the fifth pilot check valve and the first chamber 34a. A third check valve for preventing oil from flowing from the first chamber 34a to the fifth pilot check valve, the sixth pilot check valve, and the second chamber
The fourth check valve is provided between the second chamber 34b and the sixth pilot check valve to prevent the oil from flowing from the second chamber 34b to the sixth pilot check valve. A flushing device for a hydraulic circuit, characterized in that a ninth pilot check valve for blocking the flow and for allowing the oil to flow in the direction in accordance with a pilot signal is provided.