JP2000319942A - Hydraulic operation device for excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cost by integrally arranging an accumulator for accumulating pilot oil pressure in a pump case for housing a hydraulic pump for supplying pressure oil to a hydraulic actuator. SOLUTION: A valve case 53 for housing first/second safety valves composed of a solenoid valve is fixed to a side surface of a pump case 45, solenoids 46a, 47a are projected to one side of the valve case 53, and an accumulator 50 is arranged on the other side to be communicated. The accumulator 50 is arranged in a space on the side of the valve case 53 on the opposite side of the solenoids 46a, 47a to be formed in a shape capable of effectively using a useless space. Thus, since the accumulator 50 is integrally arranged in the pump case 45, there is no need to arrange the accumulator 50 in the middle of piping by newly constituting the accumulator as a separate part, so that the number of part items can be reduced, assembling manhours can be reduced, and a cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction in which an excavating work machine is provided, the work machine is driven by a hydraulic actuator, and a switching valve for switching the operation of the hydraulic actuator is operated by a pilot system. Also relates to a technology for enabling a switching operation.

[0002]

2. Description of the Related Art In a conventional excavator such as a backhoe, a bucket or a fork is mounted on the excavator through an arm or a boom, and the arm or the boom is operated by a hydraulic actuator such as a hydraulic cylinder. I do work. In order to operate the hydraulic actuator, a switching valve is used, and the switching of the switching valve is manually performed. However, since the operation force is slightly large, if the operation is performed for a long time, the user becomes tired. Therefore, a technique has been adopted in which a hydraulic pilot-type switching valve is used to switch the main hydraulic switching valve by a pilot valve (remote control valve) so that the switching can be performed with a light operation.

However, when a pilot-type switching valve is used, if the work machine is stopped at an elevated position and the operation is completed, the main hydraulic switching valve cannot be switched only by operating the operation lever, so that the hydraulic pressure gradually decreases. And the parts located below the working machine were broken, and hydraulic oil spouted when replacing the hydraulic hose. In order to prevent this, the work machine should be lowered, but it was a cumbersome operation because it was necessary to restart the engine, raise the oil pressure, and then switch the pilot valve. . Therefore, a technique is known in which an accumulator is arranged in an operating hydraulic circuit of the pilot valve so that only the pilot valve can be operated.
For example, Japanese Patent Application Laid-Open No. 6-299575.

[0004]

However, since the accumulator is formed as a separate component, the accumulator is retrofitted to a valve case or the like, which increases the cost. In addition, a space or piping for mounting the accumulator is required. However, the hydraulic control device becomes large, and the mounting position is sometimes limited.

[0005]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. That is, in claim 1, in a hydraulic operating device in which the excavator is driven by a hydraulic actuator and a valve that switches oil pressure supply to the hydraulic actuator is a pilot-type switching valve, the hydraulic oil is supplied to the hydraulic actuator. An accumulator that accumulates pilot oil pressure is provided integrally with the pump case that houses the supplied hydraulic pump.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention in which an excavator is a backhoe will be described with reference to the drawings.
1 is an overall side view of the backhoe, FIG. 2 is a hydraulic circuit diagram, FIG. 3 is a hydraulic circuit diagram of the main part, FIG. 4 is a plan view of the hydraulic pump, FIG. 5 is a front view, and FIG. is there.

First, the overall structure of the backhoe will be described. In FIG. 1, a swivel 4 is pivotably mounted on an upper part of a crawler-type traveling device 1 equipped with a pair of right and left crawlers 2.
And a cabin 6 that accommodates the driver's seat 3 and operation levers is provided on the swivel base 4, and the base of the excavator 5 is supported on the right side of the cabin 6. The rear portion of the swivel base 4 is formed in a semicircular shape in plan view so that the swivel base 4 can turn within the width of the crawler traveling device 1. An engine, a battery, a fuel tank, and the like are arranged at the rear of the cabin 6 and covered with a cover 7. In addition, the crawler traveling device 1
The earth removal plate 9 is attached to the front part of.

The excavator 5 includes a boom divided into three parts, a first boom 11, a second boom 12, and a third boom 13, and an arm 1 attached to a tip of the boom.
4 and a bucket 15.
The first boom 1 is pivotally supported to be vertically rotatable in the front-rear direction.
A boom cylinder 16 is mounted between the rotary table 1 and the swivel base 4, and the boom can be vertically rotated by expansion and contraction of the boom cylinder 16. Arm 1 on the third boom 13
4 is pivotably supported in the front-rear direction, and an arm cylinder 17 is interposed between the arm 14 and the third boom 13 so that the arm 14 can be rotated by the expansion and contraction of the arm cylinder 17. A bucket 15 is pivotally connected to the tip of the arm 14, and a bucket cylinder 19 is interposed between the two.
By expanding and contracting the bucket cylinder 19, the bucket 15 can be dumped or scooped.

A second boom 12 is pivotally supported at the tip of the first boom 11 so as to be rotatable left and right.
A third boom 13 is pivotally supported at the tip so as to be able to rotate left and right, and an offset rod 20 is pivotally connected between the first boom 11 and the third boom 13 so as to be parallel to the second boom. Offset cylinder 2 substantially parallel to 20
1 is interposed between the second boom 12 and the third boom 13. In this manner, a parallel quadruple link mechanism is constituted by the first boom 11, the second boom 12, the third boom 13, and the offset rod 20, and by extending and contracting the offset cylinder 21, the arm 14 and the bucket 15 are left and right in the front-rear direction. It is moved in parallel, and it is possible to work in a state where it is offset by guttering work or the like.

Next, a hydraulic circuit for driving the hydraulic cylinder will be described. As shown in FIG. 2, a first hydraulic pump P1, a second hydraulic pump P2, a third hydraulic pump P3, and a fourth hydraulic pump P4 are connected to the output shaft of the engine 30 so that they can be driven in parallel. On the discharge side of the hydraulic pump P1 and the second hydraulic pump P2, the steering switching valve 31
It is connected to hydraulic motors 33 and 34 provided in the crawler-type traveling device 1 through 32, so that traveling and left / right turning can be performed by operating a switching valve or a shift lever.

Further, the oil pressure is branched from the discharge oil passage of the first hydraulic pump P1 and connected to the boom lifting / lowering switching valve 35, the bucket rotation switching valve 37, and the offset drive switching valve 38 so as to be able to supply pressure oil, The discharge oil passage of the hydraulic pump P2 is connected to the swing switching valve 39 and the arm rotation switching valve 36 so as to be able to supply pressure oil.

A boom cylinder 16 is connected to the secondary side of the boom lifting / lowering switching valve 35, an arm cylinder 17 is connected to a secondary side of the arm rotation switching valve 36, and a secondary side of the bucket rotation switching valve 37. The bucket cylinder 19, the offset cylinder 21 is connected to the secondary side of the offset drive switching valve 38, and the turning motor 22 is connected to the secondary side of the turning switching valve 39. However, a cylinder and a switching valve for raising and lowering the earth discharging plate are not shown.

The boom lifting / lowering switching valve 35, the arm rotation switching valve 36, the bucket rotation switching valve 37, and the rotation switching valve 39 are pilot-type switching valves, each of which is operated via a pilot oil passage. It is connected to pilot valves 40 and 41. The pilot valves 40 and 41 are switched by turning an operation lever provided at a front portion of the driver's seat 3 so that the hydraulic cylinder can be operated. And the pilot valve 4
0.41 is supplied with pilot hydraulic pressure from the fourth hydraulic pump P4.

The first hydraulic pump P1, the second hydraulic pump P2, the third hydraulic pump P3, and the fourth hydraulic pump P4 are housed in a pump case 45 as a pump unit U, as shown in FIGS. In addition to the pumps P1, P2, P3, and P4, the pump case 45
Second safety valve 46/47 and relief valve 4
9 and the accumulator 50 of the present invention. The secondary side of the first safety valve 46 is connected to a brake release valve provided on the crawler traveling device 1 via a pilot oil passage, and the second safety valve 47
Is connected to the pilot valves 40 and 41 via filters 51 and 51.

A pump port and another sub-pump port are provided on the primary side of the second safety valve 47, and the accumulator 50 of the present invention is connected to the sub-pump port. As shown in FIGS. 4 to 6, the accumulator 50 is provided integrally with the pump case 45. The pump unit U has a pump shaft 52 suspended in the center of the pump case 45 and one end protrudes. To the output shaft of the engine 30. In the pump case 45, four hydraulic pumps P1, P2, P3, P4
Are stored, and hydraulic oil is sucked from a suction port provided at the bottom, and hydraulic pumps P1, P2, and P
Three discharge ports 61, 62, and 63 are provided, respectively.

The first and second safety valves 46, which are electromagnetic valves, are provided on the side of the pump case 45.
A valve case 53 accommodating 47 is fixedly provided, solenoids 46a and 47a are protruded from one side of the valve case 53, and an accumulator 50 is provided and communicated with the other side. The accumulator 50 is formed integrally with the pump case 45 or is detachably formed. The accumulator 50 is disposed in a space beside the valve case 53 and has a solenoid 46a.
-It is arranged on the opposite side to 47a, and has a shape that can effectively use wasteful space. And the valve case 5
Pilot hydraulic discharge ports 6 on the top, side and bottom of 3
4 to 67 are provided.

As described above, the safety valve 47 is provided between the hydraulic pump P4 for supplying the pilot hydraulic pressure and the switching valves 35 to 39 of the hydraulic actuator, and the safety valve 47 is attached to the pump case 45. Since the accumulator 50 is disposed on the side of the valve case 45 of the 47, the space on the side of the valve case can be effectively used, and a space-saving accumulator can be configured.

In this configuration, if the excavating operation is completed by the backhoe and the engine 30 is stopped in a state where the boom is raised, the boom may be lowered due to the own weight of the excavating work machine 5 and a slight leak. , It is preferable to lower it. Thus, when the operating lever is operated, the boom lifting / lowering switching valve 35, the arm rotation switching valve 36, and the bucket rotation switching valve 37 cannot be switched because the pilot hydraulic pressure is not applied conventionally. The hydraulic oil discharged from the hydraulic pump P4 is stored in the accumulator 50, and when the engine 30 is stopped, the second safety valve 47 is switched to maintain the oil pressure in the accumulator 50 and stop the engine 30. Later, if the second safety valve 47 is switched and the operating lever is operated, the pressure oil from the accumulator 50 can be sent to the operating portion of the switching valve via the pilot oil passage and switched. At this time, it cannot be raised, but can be lowered. In the present embodiment, the second safety valve 47 is switched as an electromagnetic valve by the operation of a solenoid. However, it can be switched manually.

[0019]

As described above, the present invention has the following advantages. That is, as in claim 1,
In a hydraulic operating device in which an excavator is driven by a hydraulic actuator and a valve for switching the supply of pressure oil to the hydraulic actuator is used as a pilot switching valve, a pump containing a hydraulic pump for supplying pressure oil to the hydraulic actuator Since the accumulator that accumulates the pilot oil pressure is provided integrally in the case, it is not necessary to newly configure the accumulator as a separate part and arrange it in the middle of the piping, reduce the number of parts, reduce the number of assembly steps,
The cost was also reduced. In addition, the residual pressure of the actuator can be released, and when the piping is removed during maintenance, etc., it is possible to prevent the hydraulic oil from blowing out,
Further, after the engine is stopped, the working machine can be operated to a stable posture by the pressure oil from the accumulator.

[Brief description of the drawings]

FIG. 1 is an overall side view of a backhoe.

FIG. 2 is a hydraulic circuit diagram.

FIG. 3 is a hydraulic circuit diagram of a main part of the same.

FIG. 4 is a plan view of the hydraulic pump.

FIG. 5 is a front view of the same.

FIG. 6 is a side view of the same.

[Explanation of symbols]

 5 Excavator 11 First boom 16 Boom cylinder 30 Engine 35 Boom elevating switching valve 45 Pump case 50 Accumulator 53 Valve case P1 to P4 Hydraulic pump

Claims (1)

[Claims] 1. A hydraulic operating device that drives a drilling machine by a hydraulic actuator and uses a pilot-type switching valve as a valve for switching the supply of hydraulic oil to the hydraulic actuator. A hydraulic operating device for an excavator, wherein an accumulator for accumulating pilot hydraulic pressure is integrally provided in a pump case for housing a pump.