JPH0633488A - Operating circuit of tilt dozer device - Google Patents

Abstract

PURPOSE:To make compact and lightweight a tilt dozer device and improve the operation efficiency by linking a dozer's control valve, dozer cylinder and tilt cylinder, and providing a slip ring to operate the tilt cylinder with switch operation. CONSTITUTION:An electromagnetic selector vale 26 is placed to a lower traveling body 1' of a hydraulic shovel, and a dozer's control valve 17 is provided to an upper swiveling body 8' side. After that, a dozer cylinder 5 and tilt cylinder 6 arranged to the control valve 17 and lower traveling body 1' are linked through the electromagnetic selector valve 26. Then, in the case of swivel, a switch 37 of the upper swiveling body 8' side and the electromagnetic selector 26 are linked through an electric connection (a), and the tilt cylinder 6 is operated by operation of the switch 37. A supply and discharge circuit of the dozer cylinder 5 can be used for a supply and discharge circuit of the tilt cylinder 6. According to the constitution, shape and capacity of a swivel joint 29 can be reduced to make compact and lightweight the hydraulic shovel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating circuit for an upper swing construction machine equipped with a tilt dozer device having a dozer cylinder and a tilt cylinder.

[0002]

2. Description of the Related Art FIG. 4 is a side view of a hydraulic excavator equipped with a tilt dozer device. In the figure, 1 is a lower traveling body, 2 is a lower frame of the lower traveling body 1, 3 is an arm for a dozer, 4 is an earth plate, 5 is a dozer cylinder, 6 is a tilt cylinder, and 7L and 7R are left and right traveling motors. , 8 is an upper swing body, 9 is a swing motor, 10 is a swivel joint, and 11 is a work attachment mounted on the front part of the upper swing body 8. Next, FIG. 5 is a perspective view showing the periphery of the soil discharging plate 4 in FIG.

Next, FIG. 6 is a main part circuit diagram showing an operation circuit of a tilt dozer device of the prior art. In the figure, 12
L and 12R are switching valves for traveling which control the left and right traveling motors 7R and 7R respectively, 13, 14, 15, 16 are pilot switching valves which control various hydraulic actuators mounted on the hydraulic excavator, and 17 controls the dozer cylinder 5. A control valve for dozer, 18 is a control valve for tilt that controls the tilt cylinder 6, 19 is a straight traveling valve, 20, 21, 22 are first, second and third pumps, respectively, and 23 is an oil tank.

As shown in FIGS. 4 and 5, in a hydraulic excavator equipped with a tilt dozer device, an arm 3 is provided on a lower traveling body 1 so as to be vertically swingable by a dozer cylinder 5, and an end portion of the arm (3) is provided. Further, the soil discharging plate 4 is attached to the tilt cylinder 6 so as to be tiltable. Next, a conventional operation circuit will be described with reference to FIG. In the prior art, when operating the dozer cylinder 5 or the tilt cylinder 6, respectively, the dozer control valve 17 or the tilt control valve 18 is operated. The pressure oil from the third pump 22 is the control valve 17 or 18,
It is supplied to the dozer cylinder 5 or the tilt cylinder 6 through the supply / discharge circuit 24 or 25. Thereby,
The dozer cylinder 5 or the tilt cylinder 6 can be expanded and contracted.

[0005]

Among the hydraulic excavators, particularly small excavators (including an ultra-small upper swing hydraulic excavator generally called a mini excavator) are being miniaturized and reduced in weight. However, in the tilt dozer device of the prior art, a dozer control valve and a tilt control valve for controlling the dozer cylinder and the tilt cylinder respectively are provided, and the supply and discharge circuits for them are separately arranged. Both of the control valves are arranged on the upper swing body side for convenience of driving operation, and the dozer cylinder and the tilt cylinder are arranged on the lower traveling body side, so that their separate supply / discharge circuits pass through the swivel joint. . The shape and capacity of the swivel joint, and the piping of the supply / discharge circuit were large. The present invention aims to solve the above problems.

[0006]

In the operation circuit of the tilt dozer device of the present invention, an electromagnetic switching valve is arranged on the lower traveling body,
The dozer control valve arranged on the upper revolving structure side and the dozer cylinder and tilt cylinder arranged on the lower traveling structure side communicate with each other via the electromagnetic switching valve, and one side of the upper revolving structure and the lower traveling structure is connected. A slip ring is disposed concentrically with the turning center, and a brush sliding on the slip ring is provided on the other side to form an electric connection for turning, and the electric connection for turning is provided through the electric connection. A power source and a switch on the side of the upper swing body and a solenoid of the electromagnetic switching valve are communicated with each other, and the tilt cylinder is operated by operating the switch.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a system diagram showing a main part configuration of an operation circuit according to a first embodiment of the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art.
1'is an undercarriage, 2'is a lower frame of the undercarriage 1 ', 26 is an electromagnetic switching valve, 27 is a solenoid of the electric switching valve 26, 8'is an upper revolving structure, 28 is a revolving bearing, 29 is a swivel joint. , 30 is an outer joint fixed to the lower traveling body (1 ') side of the swivel joint 29, 31 is an inner joint fixed to the upper rotating body (8') side, and 32 is fixed to the upper rotating body (8 ') side. Provided as a slip ring, 33 is an insulating member for fixing the slip ring 32, 34 is a brush fixed to the lower traveling body (1 ') side, and 35 is an insulating member for fixing the brush 34. , 36
Is a power source arranged on the upper revolving structure (8 ') side, 37 is a switch, and 0-0', which indicates the axis, is the center of rotation and the rotation axis of the swivel joint 29. FIG. 2 is a circuit diagram of the operation circuit shown in FIG.

Next, the construction of the operating circuit of the first embodiment of the present invention will be described with reference to FIGS. In the present invention, the electromagnetic switching valve 26 is arranged on the lower frame 2 ′ of the lower traveling body 1 ′,
The dozer control valve 17 arranged on the upper swing body (8 ') side and the dozer cylinder 5 and the tilt cylinder 6 arranged on the lower traveling body (1') side are communicated with each other via an electromagnetic switching valve 26, Further, the upper revolving structure 8'is provided with a slip ring 32 concentrically with the revolving center 0-0 ', and the lower traveling structure 1'is provided with a brush 34 which is in sliding contact with the slip ring 21. Part a (shown in FIG. 1)
And the power source 36 and the switch 37 on the upper swing body (8 ′) side and the solenoid 27 of the electromagnetic switching valve 26 are connected to each other via the electrical connection portion a for turning the switch (3).
The tilt cylinder 6 is configured to be operated by turning on 7).

Next, the operation of the operating circuit according to the first embodiment of the present invention will be described. First, as a first case, a case of operating the dozer cylinder 5 will be described. In this case,
The switch 37 is turned off. Since the solenoid 27 is not energized, the electromagnetic switching valve 26 is in the a position due to the spring force of its built-in spring. In this state, the expansion / contraction direction of the dozer cylinder 5 is determined, and the dozer control valve 17 is switched. For convenience of description, the case of extending the dozer cylinder 5 will be described. Position the dozer control valve 17 from the neutral position to the lower position (shown in FIG. 2)
When operated to, the pressure oil from the third pump 22 becomes
8, dozer control valve 17B position, pipe 3
9, passage 40 in swivel joint 29, pipe 41,
It is supplied to the bottom side oil chamber of the dozer cylinder 5 via the position a of the electromagnetic switching valve 26 and the pipe line 42. At the same time, the return oil from the oil chamber on the rod side of the dozer cylinder 5 passes through the conduit 4
3. Return to the oil tank 23 through the b position of the electromagnetic switching valve 26, the pipe line 44, the passage 45 in the swivel joint 29, the pipe line 46, and the b position of the dozer control valve 17. The dozer cylinder 5 can be operated as described above.

Next, as a second case, the tilt cylinder 6
The case where the tilt cylinder 6 is contracted will be described for convenience of description. First, the dozer control valve 17 is set to the neutral position, and the switch 37 is turned on. Solenoid 27
Is energized, the electromagnetic switching valve 26 is switched from the a position to the c position. Therefore, when the tilt cylinder 6 is contracted and contracted in the contracting direction, the dozer control valve 17 is switched from the neutral position to the two position. The pressure oil from the third pump 22 is supplied to the pipe 38, the two positions of the control valve 17 for the dozer, the pipe 46, the passage 45 in the swivel joint 29,
After passing through the pipeline 44, the position C of the electromagnetic switching valve 26, and the pipeline 47,
The oil is supplied to the rod-side oil chamber of the tilt cylinder 6. At the same time, the return oil from the bottom side oil chamber of the tilt cylinder 6 is supplied to the conduit 48, the position of the electromagnetic switching valve 26, the conduit 41, the passage 40 in the swivel joint 29, the conduit 39, and the control valve 17 for the dozer. Oil tank 2 through the two positions
Returned to 3. The tilt cylinder 6 can be operated as described above.

As described in the first and second cases,
In the present invention, by operating the switch (37) of the electromagnetic switching valve 26 arranged in the lower traveling body 1 ′, the supply / discharge circuit of the dozer cylinder 5 can be used as the supply / discharge circuit of the tilt cylinder 6. Therefore, it is no longer necessary to provide the supply / discharge circuit of the tilt cylinder 6 separately from the supply / discharge circuit of the dozer cylinder 5. The main pressure oil that operates the dozer cylinder 5 and the tilt cylinder 6 may be discharge pressure oil from a hydraulic pump other than the third pump 22.

Next, FIG. 3 is a system diagram showing a main part configuration of an operation circuit according to a second embodiment of the present invention. In the figure, the same reference numerals are given to those using the same components as those of the operation circuit of the first embodiment. Reference numeral 49 is a swivel joint, 50 is an outer joint of the swivel joint 49, 51 is an inner joint, b is an electric connection portion for turning, and 52 is a swivel joint 49 fixed to the outer joint 50 side (that is, the lower traveling body 1'a side). Cable bar provided through the shaft center hole 53 (the shaft center hole 53 is also the shaft center hole of the internal joint 51), 54 is a slip ring attached to the upper end of the cable bar 52, and 55 is It is a case fitting that is fixed to the inner joint 51 side (that is, the upper swing body 8′a side) and holds the brush 56. This Figure 3
The operating circuit of the second embodiment differs from the operating circuit of the first embodiment shown in FIG. 1 in that the electric circuit of the switch 37 is passed through the shaft hole 53 of the swivel joint 49. Therefore, the operation and function of the operation circuit of the second embodiment is similar to that of the operation circuit of the first embodiment.

[0013]

In the operation circuit for the tilt dozer device of the prior art of the hydraulic excavator, separate supply and discharge circuits communicating with the dozer cylinder and the tilt cylinder from both the control valve for the dozer and the tilt cylinder are passed through the swivel joint. Was there. Shape and capacity of swivel joint,
In addition, the piping of the supply and discharge circuit became large, which hindered the downsizing of the hydraulic excavator. However, in the operating circuit of the present invention, the solenoid switching valve is arranged on the lower traveling body, and the dozer control valve arranged on the upper swing body side and the dozer cylinder and the tilt cylinder arranged on the lower traveling body side are connected to the electromagnetic switching valve. In addition, a slip ring is provided on one side of the upper swing body and the lower traveling body concentrically with the swing center, and a brush slidingly contacting the slip ring is provided on the other side when turning. A power supply and switch on the upper revolving structure side are communicated with the solenoid of the electromagnetic switching valve through the electric connection for turning, and the tilt cylinder is operated by the switch operation. . Thus, by operating the switch to switch the electromagnetic switching valve, the supply / discharge circuit of the dozer cylinder can be used as the supply / discharge circuit of the tilt cylinder. That is, the supply / discharge circuit for the tilt cylinder in the prior art can be eliminated, and the shape and capacity of the swivel joint can be shortened. Therefore, in the hydraulic excavator provided with the operation circuit for the tilt dozer device of the present invention, it is possible to reduce the size and weight of the swivel joint, the supply / discharge pipe line, and the like.

[Brief description of drawings]

FIG. 1 is a system diagram showing a main part configuration of an operation circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of an operation circuit shown in FIG.

FIG. 3 is a system diagram showing a main part configuration of an operation circuit according to a second embodiment of the present invention.

FIG. 4 is a side view of a hydraulic excavator equipped with a tilt dozer device.

5 is a perspective view showing the periphery of the earth discharging plate in FIG. 4. FIG.

FIG. 6 is a main part circuit diagram showing an operation circuit of a conventional tilt dozer device.

[Explanation of symbols]

 1,1 ', 1'a Lower traveling body 5 Dozer cylinder 6 Tilt cylinder 8,8', 8'a Upper revolving structure 10,29,49 Swivel joint 17 Dozer control valve 18 Tilt control valve 22 Third pump 24 , 25 Supply / discharge circuit 26 Electromagnetic switching valve 32, 54 Slip ring 34, 56 Brush a, b Electrical connection for turning

Claims (1)

[Claims] 1. An upper-swinging construction machine in which a lower traveling body is provided with an arm swingable up and down by a dozer cylinder, and an earth-discharging plate is attached to a tip end of the arm so that the tilt cylinder is swingable by a tilt cylinder. In, the electromagnetic switching valve is arranged in the lower traveling body, the dozer control valve arranged on the upper revolving body side, and the dozer cylinder and the tilt cylinder arranged on the lower traveling body side communicate with each other via the electromagnetic switching valve, Further, a slip ring is provided on one side of the upper swing body and the lower traveling body concentrically with the swing center, and a brush slidably mounted on the slip ring is provided on the other side to provide an electrical connection portion for swing. And connect the power source and switch on the upper swing body side with the solenoid of the solenoid switching valve through the electrical connection for turning, and operate the tilt cylinder by operating the switch. An operation circuit for a tilt dozer device, which is configured as described above.