KR960004184Y1 - Oil-pressure control circuit of backhoe - Google Patents

Abstract

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Description

Hydraulic circuit of heavy equipment with confluence circuit

1 is a hydraulic circuit diagram of a heavy equipment having a joining circuit according to the prior art.

2 is a hydraulic circuit diagram of heavy equipment having a joining circuit according to the present invention.

3 and 4 are views showing another embodiment of the present invention,

3 is a view of an embodiment including a check valve in the hydraulic confluence circuit,

4 is a diagram of an embodiment having an orifice in a hydraulic confluence circuit.

* Explanation of symbols for main parts of the drawings

1, 7: hydraulic pump 6, 8: bypass flow path

2, 3, 4, 5, 9, 10, 11: Directional valve 12: First confluence line

15: logic valve 18, 21, 24, 25, 28: check valve

19, 20: parallel flow path 23, 27, 29: second confluence line

The present invention relates to a hydraulic circuit of a heavy equipment having a plurality of actuators, such as an excavator, in particular, in the hydraulic circuit of a heavy equipment equipped with two hydraulic pumps can be combined with the flow rate as desired regardless of the single operation or combined operation of the actuator It relates to a hydraulic circuit of heavy equipment having a hydraulic confluence circuit.

In general, hydraulic construction heavy equipment such as excavators are equipped with a plurality of work devices such as, for example, pours, arms, driving motors, swing motors, buckets, etc., and hydraulic circuits for operating the work devices by the operator's operation. Is installed. These hydraulic circuits include a plurality of actuators (actuators) in charge of the operation of each work device, a directional valve for changing the direction of the hydraulic oil supplied to the actuators, and a hydraulic pump for discharging the hydraulic oil by driving the engine. It is composed.

By the way, in actual operation, a high load is applied to any one actuator, and in general, the high load of this actuator is often difficult to bear with only the oil pressure by one hydraulic pump. Therefore, in the case of heavy equipment equipped with several actuators, two hydraulic pumps are installed, and a predetermined number of directional valves are hydraulically connected to each hydraulic pump to configure two groups of hydraulic networks. It is provided with a hydraulic confluence circuit configured to join the flow rate from each hydraulic pump by connecting each hydraulic network to each other so as to handle.

Figure 1 shows an embodiment of the hydraulic circuit of an excavator having a hydraulic confluence circuit according to the prior art.

According to the figure, the first hydraulic pump 1 has four directional valves 2, 3, 4, and 5 for controlling the direction of pressure oil for four actuators (not shown). It is hydraulically connected through to form a first hydraulic network (30). Similarly, three bypass valves 9, 10, 11 for controlling the direction of pressure oil for three actuators (not shown) are hydraulically connected to the bypass flow path 8 from the second hydraulic pump 7. Two hydraulic network 40 is formed, and two hydraulic confluence circuits 12 and 13 are installed between each hydraulic network 30 and 40.

Hereinafter, the hydraulic joining operation of one circuit 12 of the hydraulic joining circuits will be described. This confluence circuit 12 is an arm confluence circuit, which is generally provided to join the discharge flow rate of the first hydraulic pump 1 toward the direction of the direction change valve 11 for arm operation control. Accordingly, the confluence circuit 12 is connected between the inlet port 11a side of the arm directional valve 11 and the bypass flow path 6 of the first hydraulic pump 1, as shown in FIG. do.

First, when the directional control valve 11 is operated alone, the flow path of the pilot line a connected to the logic valve 15 from the auxiliary spun 14 installed in the valve is blocked, so that the back pressure is reduced. Acts on the top surface of the logic valve 15 through a pilot line (a). Then, the pressure oil discharged from the first hydraulic pump 1 and flowing through the bypass flow path 6 does not return to the return tank 17 through the logic valve 15 and the return line 16, but instead checks. It passes through the arm confluence line 12 via the valve 18, and is connected to the swelling flow path 19 by the arm direction switching valve 11 side. The pressure oil thus joined is connected only to the inlet port 11 side of the arm direction switching valve 11 because of the check valve 20 on the parallel flow path 19. At this time, the pressure oil pressure discharged from the second hydraulic pump 7 is applied to the inlet port 11a of the valve 11 through the bypass flow path 8 and the check valve 21, so that the first hydraulic pump 1 It is combined with the hydraulic oil from and supplied to the valve 11. Therefore, in the arm direction switching valve 11, the pressurized oil discharged from the first and second hydraulic pumps 1 and 7 joins and is supplied to be able to sufficiently handle the high load.

However, in the case of the hydraulic circuit having the joining circuits 12 and 13 as described above, if any one of the four directional valves 2, 3, 4, 5 in the second hydraulic network 30 is operated, That is, at the same time as the operation of the arm direction switching valve 11, any one of the four direction switching valves (2, 3, 4, 5), for example, the fourth valve (5) is operated simultaneously and combined operation mode When the bypass oil flow path 6 of the hydraulic oil discharged from the first hydraulic pump 1 is cut off by this valve (5), the supply of the hydraulic oil to the arm confluence line 12 is stopped, arm direction Only the pressurized oil discharged from the second pump 7 and passed through the bypass flow path 8 and the check valve 21 is transferred to the switching valve 11 side. Therefore, according to the conventional hydraulic confluence circuit as described above, the desired confluence circuit is formed when the actuator is operated alone, but in the combined operation mode in which two or more actuators are operated at the same time, the confluence circuit is not formed so that it cannot effectively handle the high load. there is a problem.

An object of the present invention is to solve the problems of the conventional hydraulic confluence circuit as described above, the hydraulic confluence circuit that can always be hydraulically joined as desired, regardless of whether the actuator of the heavy equipment operation mode or combined operation mode It is to provide.

According to an embodiment of the present invention, a first confluence line having a conventional hydraulic confluence circuit is installed between the first and second hydraulic networks through which the hydraulic oil discharged from the first and second hydraulic pumps flows, A second confluence line was additionally formed between the parallel flow passages of the directional valve side and the parallel flow passages of the second hydraulic network through drilling, so that the hydraulic oil can be effectively joined in the single operation or the composite operation mode of the actuator.

According to another embodiment of the present invention provides a hydraulic confluence circuit that can control the confluence direction of the pressure oil in one direction by installing a check valve at a predetermined position in the additional hydraulic confluence line.

According to another embodiment of the present invention by installing an orifice in the additional hydraulic confluence line is provided that can adjust the flow distribution to prevent the bias of the flow rate according to each load difference when two or more actuators are operated simultaneously.

Hereinafter, with reference to the accompanying drawings, the hydraulic circuit of the present invention as described above in more detail.

2 to 4 show the hydraulic circuit of an excavator having a hydraulic confluence circuit according to the present invention, in which FIG. 2 is a case where an additional confluence line is simply formed by drilling, and FIG. 3 checks in this additional confluence line. In the case of installing a valve, Figure 4 shows the installation of an orifice in this additional confluence line.

First, referring to Figure 2, in the hydraulic circuit of an excavator having a hydraulic confluence circuit according to the present invention, the first and second hydraulic network (30, 40) connected to the first and second hydraulic pump (1, 7), respectively ) Is almost the same as the conventional hydraulic circuit shown in FIG. 1 except for the configuration of the hydraulic confluence circuit, in particular the arm confluence circuit, the same reference numerals are given to the same parts as in FIG. Omit the description.

In the hydraulic circuit according to the present invention, the pressure oil discharged from the first and second hydraulic pumps 1 and 7 passes through the bypass passages 6 and 8 and the check valves, respectively. It can be supplied to the inlet port side of 9-11, and it is made to flow through each parallel flow path 19 and 22 at the same time. At this time, as shown in FIG. 2, the parallel passage 19 and the first hydraulic pump 1 side of the arm direction switching valve 11 side connected to the bypass passage 8 of the second hydraulic pump 7 A first hydraulic confluence line 12 having a check valve 18 is provided between the bypass passages 6 as in the conventional case. In addition, a second hydraulic confluence line 23 having a simple structure is formed between the parallel flow passage 19 on the arm direction switching valve 11 side and the parallel flow passage 22 on the first hydraulic pump 1 side. It is provided.

The operation of the hydraulic confluence circuit at the time of arm operation in the hydraulic circuit of the above configuration will be described.

First, in case of the arm only operation mode, the pilot is connected to the bypass flow path switching valve 24 of the first hydraulic network 30 from the auxiliary spool 14 of the arm directional valve 11 as described in the conventional embodiment. The oil pressure which is blocked by the flow path of the line a and discharged from the 1st hydraulic pump 1 and passes through the bypass flow path 6 is not returned to the return tank 17, but the 1st provided with the check valve 18. It is connected to the parallel flow path 19 on the arm direction switching valve 11 side through the hydraulic confluence line 12. At this time, the pressure oil pressure from the second hydraulic pump 7 is applied to the inlet port 11a of the arm direction switching valve 11 via the bypass flow path 8 and the check valve 21, and at the same time, the first hydraulic pump A part of the hydraulic oil from the first hydraulic pump 1 is also transferred to the inlet port 11a of the arm directional valve 11 through the second hydraulic confluence line 23 connected to the parallel passage 22 on the (1) side. Is approved. Therefore, in the arm only operation mode, the oil pressure from the first hydraulic pump 1 and the oil pressure from the second hydraulic pump 7 join and are supplied to the arm direction switching valve 11 so that it can sufficiently handle the high load. Will be.

On the other hand, when the directional valve 4 in the first hydraulic network 30 is operated alone, the pressure oil discharged from the first hydraulic pump 1 passes through the bypass passage 6 and the check valve 24. The pressure oil which is applied to the inlet port 4 of the valve 4 and discharged from the second hydraulic pump 7 and passes through the bypass flow path 8 in the drawing is a check valve 21 on the arm direction switching valve 11 side. Is applied to the parallel flow path (19), and then connected to the parallel flow path (22) on the side of the first hydraulic pump (1) via the second hydraulic confluence line (23). The pressure oil of the second hydraulic pump 7 connected to the parallel flow passage 22 passes through the orifice 25 and the check valve 26 in the parallel flow passage on the side of the valve 4 and the inlet port 4a of the valve 4. Leads to. At this time, the joining is not performed in the first confluence line 12 because of the check valve 18. Therefore, during the single operation of the valve 4, the pressure oil discharged from the first and second hydraulic pumps 1 and 7 are joined and supplied to sufficiently handle the high load.

If, in the hydraulic circuit of the above configuration, one directional valves 4 and 11 in each hydraulic network 30 and 40 are operated at the same time, that is, in the combined operation mode in which two actuators are operated at the same time, By the operation of the direction switching valve 4 on the side of the first network 30, the pressurized oil flow in the bypass flow path 6 is cut off, and thus the pressurized oil through the first confluence line 12 does not occur. However, in this case, since a part of the pressurized oil from the 1st hydraulic pump 1 flows through the parallel flow path 22, the pressurized oil through the 2nd confluence line 23 is made. That is, the hydraulic oil passing through the parallel flow passage 22 is connected to the inlet port 11a of the arm direction switching valve 11 through the confluence line 23 and merges with the hydraulic oil supplied from the second hydraulic pump 7. It can be supplied to the arm direction switching valve (11).

Therefore, according to the hydraulic confluence circuits having the first and second hydraulic confluence lines 12 and 23 according to the present invention, the hydraulic confluence operation is made as desired regardless of whether the actuator is a single operation mode or a composite operation mode. Depending on the configuration of the hydraulic confluence line 23, the confluence of the pressure oil may be made in both directions.

In the embodiment shown in FIG. 3, the check valve 28 is installed in the second confluence line 27, and the first circuit film 30 is moved from the first circuit film 30 side to the second network 40 side in the single or combined operation mode of the actuator. This is an embodiment of the hydraulic confluence circuit that guarantees only the confluence of and not the converse.

In addition, in the embodiment shown in FIG. 4, the orifice 31 is installed in the second confluence line 29, so that single or combined operation is possible, and in particular, the arm direction switching valve 11 and the first network ( In the case of simultaneously operating the direction switching valve 4 of 30), the flow rate distribution is adjusted by installing an orifice 31 at an intermediate position of the confluence line 29 in order to prevent the unevenness of the flow rate according to the load difference. At this time, in order to form the orifice 31 by measuring the flow rate according to the load test of the working device to determine the size of the orifice according to this, it is achieved by installing the orifice plug processed in this standard in the joining line (29).

As described above, in the hydraulic confluence circuit of the heavy equipment according to the present invention, the parallel flow path of the directional valve connected to one hydraulic pump and the bypass flow path from the other hydraulic pump are connected to a conventional hydraulic confluence line having a check valve. By connecting the parallel flow path of the one hydraulic pump and the parallel flow path of the other hydraulic pump to another hydraulic confluence line, the hydraulic oil from each hydraulic pump joins each other regardless of the single operation mode or the combined operation mode of the actuator to change the direction of the high load. It offers the advantage of being able to be supplied to the valve side.

Claims (6)

To the bypass passage 6, the first parallel passage 22, and the bypass passage 6 through which the first and second hydraulic pumps 1 and 7 and the discharge pressure oil of the first hydraulic pump 1 pass. A second flow path connected to the bypass flow path 8, a second parallel flow path 19, and a bypass flow path 8 through which the discharge pressure oil of the second hydraulic pump 7 passes; In the hydraulic circuit of the heavy equipment consisting of the directional valve 11, the first hydraulic pressure is connected between the bypass passage 6 and the second parallel passage 22 passing through the first directional valve 4 Hydraulic circuit of the heavy equipment comprising a confluence line 12 and a hydraulic confluence circuit consisting of a second hydraulic confluence line connected between the first parallel flow path 22 and the second parallel flow path 19. . 2. The hydraulic circuit according to claim 1, wherein a check valve (18) is installed in the first hydraulic confluence line (12). The hydraulic circuit of claim 1, wherein the second hydraulic confluence line is a confluence line formed by a drilling operation. 2. The hydraulic circuit of claim 1, wherein the second hydraulic confluence line is a confluence line (27) having a check valve (28). 2. The hydraulic circuit according to claim 1, wherein the second hydraulic confluence line is a confluence line (29) having an orifice (31). 6. The orifice according to claim 5, wherein the orifice (31) is an orifice determined by measuring the flow rate according to the load test of the direction change valves (4, 11) during the combined operation of the first and second direction change valves (4, 11). Hydraulic circuit of heavy equipment, characterized in that consisting of orifice plug having a standard.