JP2608194B2 - Backhoe hydraulic operation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a sub-control valve separately from a main control valve for controlling a hydraulic oil of a hydraulic cylinder for driving a boom of a backhoe apparatus up and down, and each control valve is constituted by a hydraulic pilot operation type. In addition, the present invention relates to a hydraulic operating structure of a backhoe in which a pilot oil passage of a hydraulic pilot operation valve for raising a boom is connected to an upward pilot oil chamber of each control valve.

[0002]

2. Description of the Related Art In the above-mentioned hydraulic operating structure of a backhoe, conventionally, a pilot oil passage of a hydraulic pilot operation valve for boom lowering operation of the sub-control valve is fixed while being connected to a drain oil passage.

[0003]

The above-mentioned conventional structure has a structure in which the pressure supplied from the main hydraulic pump via the main control valve is increased in excavation work in order to increase the boom ascending speed and improve work efficiency. In addition to oil, pressure oil from another hydraulic pump is joined via the sub-control valve,
Also, in the case of the lowering operation of the boom, since the backhoe device adds a large weight to the hydraulic operating force, when the hydraulic oil is joined in the same manner as the raising operation, the speed becomes too fast, and the vehicle stops during the lowering operation. In such a case, a large shock is likely to occur, which is dangerous for work. Therefore, the speed of the boom operation is not increased when the vehicle descends. However,
In the backhoe device, not only excavation work such as earth and sand, but also, for example, there is a case where a breaker is installed in place of a bucket at the tip to break concrete, and in such an operation, the descent speed is reduced. There was a disadvantage that the work became slower and the work efficiency became worse. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems with a simple structure improvement while effectively utilizing the advantages of the hydraulic pilot operation type.

[0004]

According to a feature of the present invention, in the hydraulic operating structure of the backhoe described at the beginning, the descending pilot oil passage communicating with the boom descending pilot oil chamber of the sub control valve is provided with a drain oil. It is provided so as to be freely switchable between a state in which it is connected to a passage and a state in which it is connected to a pilot oil passage of a hydraulic pilot operation valve for lowering the main control valve via a flow dividing member.

[0005]

When the boom lowering speed does not need to be increased, the pilot oil passage for the boom lowering operation of the sub-control valve is connected to the drain oil passage. Only the valve is operated, the pressure oil does not merge, and the boom descends at a relatively low speed. Also, when it is necessary to lower the boom at a high speed, such as in concrete breaking work, pile driving work, or ground leveling work with a bucket, the main control of the pilot oil passage for the boom lowering operation of the secondary control valve is performed. By connecting to the pilot oil passage for lowering operation of the valve via a diverting member, even at the time of lowering operation, pressure oil is merged and supplied according to the operation of not only the main control valve but also the sub-control valve to operate at high speed. Will be.

[0006]

As described above, a structure in which the pilot oil passage for the boom lowering operation of the sub-control valve is simply connected and switched to either the drain oil passage or the branching member is sufficient, so that only a simple improvement of the existing hydraulic structure can be achieved. This makes it possible to provide a backhoe with excellent workability even for special tasks.

[0007]

Embodiments will be described below with reference to the drawings. FIG.
Shows the backhoe. The backhoe is provided with a turning motor M3 on an upper part of a traveling machine base 2 provided with a crawler traveling device 1 driven by a pair of left and right hydraulic motors M1 and M2.
The swivel 3 is mounted so that the swivel 3 can freely rotate around the vertical axis, and the driving unit 4 and the control unit 5 are arranged on the swivel 3.
A backhoe device 7 is connected via a swing bracket 6 so that it can be stored and oscillated about a longitudinal axis via a swing bracket 6 by driving a swing cylinder C1. The backhoe device 7 includes a boom 8, an arm 9, and a bucket 10, and is configured to be able to perform an excavation operation by swinging drive by a boom cylinder C2, an arm cylinder C3, and a bucket cylinder C4, respectively.

Next, the hydraulic circuit structure will be described. FIG.
As shown in the figure, the hydraulic control valve V1 for the swing cylinder, the hydraulic control valve V2 for the swing motor, and the like are configured as a center bypass type multiple valve, and hydraulic oil is supplied from the first hydraulic pump P1 to these valves. Hydraulic control valve V3, the main hydraulic control valve V4 of the boom 8, and the hydraulic control valve V5 for the right traveling hydraulic motor are each configured as a center bypass type multiple valve, to which hydraulic oil is supplied from the second hydraulic pump P2. Then, the hydraulic control valve V6 for the left traveling hydraulic motor, the auxiliary hydraulic control valve V7 of the boom 8, the hydraulic control valve V8 for the arm cylinder, and the like are configured as a center bypass type multiple valve. A hydraulic circuit is configured to supply pressure oil. Then, each control valve V for driving the backhoe device 7
3, V4, V7, V8, the swing control valve V2 and the swing cylinder control valve V1 are each configured as a hydraulic pilot operation type, and these are a pair of left and right cross swing operation levers 11.
It is controlled by the operation of R and 11L. That is, the arm cylinder C3 is operated via the hydraulic pilot operation valves PV1 and PV2 by operation of the one operation lever 11R in a predetermined direction, and the hydraulic pilot operation valves PV3 and PV are operated by operation in the other direction.
4, the swing motor M3 or the swing cylinder C
1 is operated, the boom cylinder C2 is operated via the hydraulic pilot operation valves PV5, PV6 by operating the other operation lever 11L in a predetermined direction, and the hydraulic pilot operation is operated by operating in the other direction. Valve PV7,
A hydraulic pilot operation system is configured to operate the bucket cylinder C4 via the PV8. Note that the swing motor M
The switching valve 12 selectively uses the swing cylinder C1 and the swing cylinder C1.

The pilot oil passage L1 of the hydraulic pilot operation valve PV5 for raising the boom 8 is connected to the rising pilot oil chamber of the main hydraulic control valve V4 and the auxiliary hydraulic control valve V7. A descending pilot oil passage L2 communicating with the boom descending pilot oil chamber of the sub control valve V7.
Is connected to the drain oil passage L3 and the main control valve V
Diverting joint 13 in the pilot oil passage L4 for lowering operation 4
It is provided so as to be freely switchable to a state of connection via (an example of a flow dividing member). Specifically, as shown in FIG.
The boom lowering pilot oil passage L2 of the sub-control valve V7 is constituted by a flexible hose 14, and the other end of the hose 14 is screwed into a connection portion 16 formed in a drain pipe 15 constituting a drain oil passage L3. The connection state and the state where the main control valve V4 is screwed and connected to the branching joint 13 provided in the middle of the lowering pilot oil passage L4 of the main control valve V4 can be replaced. When connecting to the drain oil passage L3, the connecting portion of the branching joint 13 is closed with a cap nut or the like, and when connecting to the branching joint 13, the connecting portion 16 of the drain pipe 15 is closed with a cap nut or the like. It is. With such a configuration, when the boom 8 is lowered, the pressure oils from the two hydraulic pumps P2 and P3 can be combined and lowered at high speed, and only the pressure oil from one hydraulic pump P2 can be lowered. Can be easily switched to the low-speed operation state in which is supplied.

Alternative Embodiment As described above, the boom-lowering-side pilot oil passage L2 of the sub-control valve V7 is replaced with a flexible hose 14 and is connected to the pilot oil passage L2. A simple oil passage switching tool that can be switched between a state of connection to the diversion joint 13 and a state of connection to the drain oil passage L3 may be provided.

[0011] In the claims, reference numerals are provided to facilitate comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram

FIG. 2 is a side view of an oil passage switching unit.

FIG. 3 is an overall side view of the backhoe.

[Explanation of symbols]

 7 Backhoe device 8 Boom 13 Dividing member L1, L2, L4 Pilot oil passage L3 Drain oil passage PV5, PV6 Hydraulic pilot operation valve V4 Main control valve V7 Secondary control valve

Claims (1)

(57) [Claims] An auxiliary control valve (V7) is provided separately from a main control valve (V4) for controlling hydraulic oil of a hydraulic cylinder (C2) that drives a boom (8) of a backhoe device (7) up and down. The valves (V4) and (V7) are configured as a hydraulic pilot operated type, and the pilot oil passage (L1) of the hydraulic pilot operated valve (PV5) for raising the boom (8) is connected to the control valve (V4). , (V7), the hydraulic operating structure of the backhoe connected to the rising pilot oil chamber, wherein the lower pilot oil passage (L2) communicating with the boom lowering pilot oil chamber of the sub-control valve (V7) is connected. , Drain oil passage (L
3) and a state in which the main control valve (V4) is connected to a pilot oil passage (L4) of a hydraulic pilot operation valve (PV6) for lowering the main control valve (V4) via a flow dividing member (13). Hydraulic operation structure of backhoe freely provided.