JPH051429A - Backhoe hydraulic circuit structure - Google Patents

Abstract

(57) [Summary] [Purpose] In the backhoe of the hydraulic pilot operation system, a malfunction occurred in the hydraulic pump for pilot operation pressure supply, while using other existing hydraulic pumps without the need for complicated structural improvement. Allows you to continue working, even if. [Structure] The pressure oil from the first hydraulic pump P1 is supplied to each hydraulic pilot operating valve, and the second hydraulic pump P
A first state in which the pressure oil from the second hydraulic pump P2 is supplied to each hydraulic actuator for work, and the pressure oil from the second hydraulic pump P2 is connected to the hydraulic pilot operation valves and the An oil passage switching valve 14 which is freely switchable between the hydraulic actuators and the second state in which the oil is divided and supplied is provided in the pressure oil supply passages from the hydraulic pumps P1 and P2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises hydraulic control valves for a plurality of hydraulic actuators, each of which is of a hydraulic pilot operated type, and a hydraulic oil for pilot operation is supplied from a first hydraulic pump to each hydraulic pilot operated valve. The present invention relates to a hydraulic circuit structure of a backhoe configured to supply pressure oil to each of the hydraulic actuators from a second hydraulic pump.

[0002]

2. Description of the Related Art In the hydraulic circuit structure of the above backhoe, conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-56706, the hydraulic pilot operating valves are operated only by a dedicated hydraulic pump. It was configured to supply oil.

[0003]

However, in the above-mentioned conventional structure, when the hydraulic pump for supplying the pilot operating pressure has a reduced discharge amount or pressure due to, for example, dust trapped or seals being damaged, Since the pilot operated valve cannot be operated, even if the other main hydraulic pumps for driving the backhoe device are normal, there is a drawback that the backhoe device cannot perform excavation work, and there is room for improvement. It is an object of the present invention to eliminate the above-mentioned problems by effectively utilizing an existing hydraulic pump and making a simple structural improvement.

[0004]

According to a characteristic configuration of the present invention, in the hydraulic circuit structure of the backhoe described at the beginning, the pressure oil from the first hydraulic pump is supplied to each of the hydraulic pilot operation valves, and First pressure oil supplied from a second hydraulic pump is supplied to each hydraulic actuator.
An oil passage that is switchable between a state and a second state in which the pressure oil from the second hydraulic pump is split and supplied to each of the hydraulic pilot operation valves and each of the hydraulic actuators via a diversion valve. The switching valve is provided in the pressure oil supply passage from each of the hydraulic pumps.

[0005]

In normal operation, by setting the oil passage switching valve to the first state, pressure oil is supplied to each hydraulic pilot operation valve only from the first hydraulic pump, and the hydraulic actuator is supplied to the hydraulic actuator. Since pressure oil is supplied from another second hydraulic pump, normal hydraulic pilot operation can be performed.
When the first hydraulic pump fails, the oil passage switching valve is switched to the second state so that the pressure oil from the second hydraulic pump is supplied to the respective hydraulic actuators, and at the same time through the flow dividing valve. Is also supplied to each hydraulic pilot operating valve, and the hydraulic control valve for the hydraulic actuator can be switched and operated.

If the second hydraulic pump is for supplying pressure oil to a hydraulic actuator other than the hydraulic actuator for excavation work of the backhoe device, the amount of pressure oil supply to the hydraulic actuator will decrease during excavation work. There is no.

[0007]

Therefore, it is not necessary to make a complicated structural improvement such as providing a spare hydraulic pump and an oil passage switching mechanism by using other existing hydraulic pumps, and it is possible to simply add a simple member. As a result, the work can be continued even if the hydraulic pump for supplying the pilot operating pressure oil fails.

[0008]

Embodiments will be described below with reference to the drawings. Figure 3
Shows the backhoe. This back hoe has a swing motor M3 on the upper part of a traveling machine base 2 including a crawler traveling device 1 driven by a pair of left and right hydraulic motors M1 and M2.
With this, the swivel base 3 is mounted so as to be fully swivel around the axis of the vertical axis, and the driving part 4 and the control part 5 are arranged on the swivel base 3, and
A backhoe device 7 is connected via a swing bracket 6 so as to be retractable and swingable around a vertical axis center by driving a swing cylinder C1. The backhoe device 7 includes a boom 8, an arm 9 and a bucket 10. The backhoe device 7 is configured to be rockably driven by a boom cylinder C2, an arm cylinder C3, and a bucket cylinder C4 to perform excavation work. Further, a dozer device 15 is provided at the front part of the traveling machine base 2 so as to be vertically movable by a dozer cylinder C5.

Next, the hydraulic circuit structure will be described. Figure 1
As shown in FIG. 5, the swing cylinder hydraulic control valve V1, the swing motor hydraulic control valve V2, and the dozer cylinder hydraulic control valve V9 are configured as a center bypass type multiple valve, and the bucket cylinder hydraulic control valve V3 and the boom 8 are provided. Main hydraulic control valve V
4. Each of the right side traveling hydraulic motor hydraulic control valves V5 is configured as a center bypass type multiple valve, and the left side traveling hydraulic motor hydraulic control valve V6, the sub hydraulic control valve V7 of the boom 8, the arm cylinder hydraulic control valve V8, etc. Is configured as a center bypass type multiple valve, and a hydraulic circuit is configured to separately supply pressure oil to these valve blocks from three hydraulic pumps P2, P3, P4, respectively. Then, the control valves V3, V4, V7, V8 for driving the backhoe device 7 and the swing control valve V
2 and the swing cylinder control valve V1 are hydraulically pilot operated, and these are controlled by operating a pair of left and right cross swing type operation levers 11R and 11L. That is, the hydraulic pilot operation valves PV1 and PV2 are operated by operating one operation lever 11R in a predetermined direction to switch the arm cylinder hydraulic control valve V8 by pilot hydraulic pressure to operate the arm cylinder C3, and the hydraulic pressure is operated in the other direction. A hydraulic pilot operation system is configured to operate the swing motor M3 or the swing cylinder C1 by operating the pilot operation valves PV3 and PV4 to switch the swing control valve V2 and the swing cylinder control valve V1 by pilot hydraulic pressure, and the other operation lever. 11L is operated in a predetermined direction to operate the hydraulic pilot operating valves PV5 and PV6 to switch the boom hydraulic control valves V4 and V7 by pilot hydraulic pressure to operate the boom cylinder C2, and to operate in the other direction to operate the hydraulic pilot operating valve PV7. , PV8 by operating the pilot oil pressure Have configured hydraulic pilot operation system to operate the bucket cylinder C4 are switched Sunda hydraulic control valve V3. The swing motor M3 and the swing cylinder C1 are selectively used by the switching valve 12, and pressure oil is supplied from another hydraulic pump P1 (hereinafter referred to as a first hydraulic pump) to each hydraulic pilot operation valve. Is configured to supply.

Then, as shown in FIG. 2, the hydraulic pump P2 for the first hydraulic pump P1 and the swing motor M3, etc.
In each pressure oil supply path (hereinafter referred to as the second hydraulic pump), the pressure oil of the first hydraulic pump P1 is supplied to each hydraulic pilot operation valve PV1 to PV8, and the pressure oil of the second hydraulic pump P2 is supplied to the swing motor M3. And the like, and the pressure oil of the second hydraulic pump P2 is supplied to the respective hydraulic pilot operation valves PV1 to PV8 via the flow priority valve 13 (an example of a shunt valve). An oil passage switching valve 14 that can be switched between two states is interposed. That is, in the first state, the circuits are arranged in parallel as in the case where the switching valve 14 is not provided, and when the circuit is operated in the second state, the control flow by the flow priority valve 13 in the pressure oil of the second hydraulic pump P2 is controlled. Is supplied to each of the hydraulic pilot operation valves PV1 to PV8, and the surplus flow is supplied to the swing motor M3.
Are supplied to hydraulic actuators such as. With this configuration, the oil passage switching valve 14 is set to the first state during normal work, and the oil passage switching valve 14 is set to the first state even if a problem occurs in the first hydraulic pump P1. By switching to the two states, the driving operation of the backhoe device 7 becomes possible.

It should be noted that reference numerals are added to the claims to facilitate the comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

[Fig. 1] Hydraulic circuit diagram

FIG. 2 is a hydraulic circuit diagram of an oil passage switching valve installation portion.

[Fig. 3] Overall side view of the backhoe

[Explanation of symbols]

7 Backhoe equipment 13 shunt valve 14 Oil passage switching valve P3 2nd hydraulic pump P4 1st hydraulic pump

Claims (2)

[Claims] 1. A hydraulic control valve for each of a plurality of hydraulic actuators is configured to be a hydraulic pilot operating type, and pilot operating oil is supplied to each hydraulic pilot operating valve from a first hydraulic pump (P1). It is configured and a second is provided for each hydraulic actuator.
A hydraulic circuit structure of a backhoe configured to supply pressure oil from a hydraulic pump (P2), wherein pressure oil from the first hydraulic pump (P1) is supplied to each of the hydraulic pilot operation valves, and The first state in which the pressure oil from the second hydraulic pump (P2) is supplied to each of the hydraulic actuators and the pressure oil from the second hydraulic pump (P2) pass through the flow dividing valve (13). And an oil passage switching valve (14) which is freely switchable between the hydraulic pilot operation valve and the second state in which the hydraulic pilot actuator is split and supplied.
Is a hydraulic circuit structure of a backhoe in which a hydraulic oil supply path from each of the hydraulic pumps (P1) and (P2) is interposed. 2. The hydraulic circuit for the backhoe according to claim 1, wherein the second hydraulic pump (P2) supplies pressure oil to a hydraulic actuator other than the hydraulic actuator for excavation work in the backhoe device (7). Construction.