JPH0596158U - Hydraulic circuit of work machine - Google Patents

Abstract

(57) [Abstract] [Purpose] The earthwork plate itself allows smooth ground leveling without tilt correction for unevenness of the road surface during back leveling. In a hydraulic circuit A of a working machine including at least a lift operating valve 4 and a tilting operating valve 5 for operating each working machine cylinder 2, 3 such as a bulldozer earthwork plate 1, etc., a tilting operating valve is provided. 5 is provided with a floating position, and circuits 6a and 6b from the tilt operation valve 5 to the tilt cylinder 3 and circuits 8a and 8b to the tank 7 are connected to each other to connect the circuits 8a and 8b on the tank 7 side. A suction valve 9 that allows suction from the tank 7 is provided. [Effect] In the leveling work at the time of back leveling, the tilt and the floating state can be obtained, and the work is easy and the finish is also good.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a working machine for construction machines such as bulldozers, and more particularly to a hydraulic circuit for working machines such as earthwork boards.

[0002]

[Prior Art]

 Conventionally, a bulldozer is provided with an earthworking plate in front of the vehicle body, and the earthworking work is performed by changing the earthworking plate up / down, left / right tilt, and left / right angle while the vehicle is traveling. By the way, as shown in FIGS. 5 (a) and 5 (b), the lift cylinders 22 for raising and lowering the earthworking plate 21 are located on the left and right sides of the working machine frame 23, and one end of the earthworking plate 21 is placed above the other end. One tilt cylinder 24 that tilts in the direction is installed between the earthwork plate 21 side and the work machine frame 23, and the angle cylinder 25 that moves the left and right of the earthwork plate 21 back and forth with respect to the vehicle body is the earthwork plate. 21 are provided on the left and right sides between the work machine frame 23 and the work machine frame 23. In order to supply hydraulic pressure to each of these cylinders to operate them, the oil from the tank 26 is driven by the pump 27, and the generated hydraulic pressure is applied to the angle control valve 28, the tilt control valve 29, and the lift control valve 30. To the desired cylinder by switching the operated operation valve to operate the cylinder, thereby moving the earthworking machine 21.

In this case, the lift operation valve 30 has three positions of up, down, and floating in addition to the neutral position, and the tilt and angle operation valves 29, 28 have a neutral position, a left position, and a left position, respectively. It has two positions on the right. Therefore, the operation pattern of the lift-tilt lever moves the lift lever to any of the up, down and floating positions as shown in Fig. 6 and then moves the tilt lever to the left or right (or the tilt lever first). The lift lever can be moved later, though). And when doing the leveling work in the floating position in the bulldozer (see Fig. 7), the footprints are leveled with the back as the final finish, but it is a load to smooth the back leveling. Accordingly, the earthwork plate 21 is moved up and down by its own weight. Further, the oil passage of the tilt cylinder 24 enables a tilt operation by a series.

[0004]

[Problems to be solved by the device]

 However, in the conventional oil passage, movement of the earthwork plate 21 in the tilt direction occurs due to the unevenness of the road surface during back leveling. Therefore, the horizontal posture of the earthwork plate 21 must be corrected by tilting each time. There wasn't.

In view of this, the present invention provides a circuit of a working machine capable of smooth grounding by the earthwork plate itself without tilt correction for unevenness of the road surface at the time of back ground leveling The purpose is to eliminate the drawbacks.

[0006]

[Means for Solving the Problems]

 As a means for solving the above-mentioned problems of the prior art, the present invention provides a hydraulic circuit of a working machine equipped with at least a lift control valve and a tilt control valve for operating each work machine cylinder such as a bulldozer earthwork plate. According to claim 1, the tilt operation valve is provided with a floating position, and the oil passage extending from the tilt operation valve to the tilt cylinder and the oil passage extending to the tank are connected to each other, so that each of the connected oils on the tank side is connected. A suction valve capable of sucking from a tank is provided in the passage, and the oil passage from the tilt operation valve to the tilt cylinder and the oil passage to the tank are connected to each other, and the connection is made. Each oil passage on the tank side is equipped with a suction valve that allows suction from the tank, and a switching valve having two positions of neutral and floating is provided between both oil passages.

[0007]

[Action]

 According to the above structure, since the tilt operation valve is provided with the floating position in both claims 1 and 2, tilt correction is not necessary for unevenness of the road surface, that is, the earthwork plate is automatically changed by switching to the floating position. Since it corresponds, a smooth ground level can be obtained.

[0008]

【Example】

 1 is an embodiment of a hydraulic circuit of a working machine according to claim 1 of the present invention and an earthmoving machine in which the hydraulic circuit is coupled, FIG. 2 is a lift-tilt operation pattern diagram in FIG. 1, and FIG. 3 is a book. A hydraulic circuit of a working machine according to claim 2 of the invention and a circuit diagram showing an embodiment in which the hydraulic circuit is connected, and FIG. 4 is another embodiment of the switching valve of FIG.

Hereinafter, claim 1 of the present invention will be described with reference to an embodiment shown in FIGS. According to claim 1 of the present invention, a hydraulic circuit A for a working machine equipped with at least a lift operation valve 4 and a tilt operation valve 5 for operating each cylinder 2, 3 of the work machine such as an earthwork plate 1 of a bulldozer. In addition, the tilt operation valve 5 is provided with a floating position, and the oil passages 6a and 6b extending from the tilt operation valve 5 to the tilt cylinder 3 and the oil passages 8a and 8b extending to the tank 7 are connected to each other. Each of the oil passages 8a and 8b on the tank 7 side is provided with a suction valve 9 capable of sucking from the tank 7.

The earthwork plate 1 is attached to a vehicle body (not shown) in a state of being rotatably attached to the work machine frame 10. A pair of left and right lift cylinders 2 and 2 are mounted on the work machine frame 10, and a tilt cylinder 3 and a pair of angle cylinders 11 are mounted between the earthwork plate 1 and the work machine frame 10. ing. Each of these cylinders 2, 3 and 11 is connected to a hydraulic circuit A, respectively. The hydraulic circuit A supplies the operating oil of the tank 7 from the pump 12 through the oil passage in the order of the angle operation valve 13, the tilt operation valve 5 and the lift operation valve 4, respectively, and when each operation valve is in the neutral position. It is designed to return to the tank 7 without being supplied to the cylinder. However, for example, when the lift operation valve 4 is switched from the neutral position to the upper position, the oil discharged from the pump 12 is guided to the rod side of the lift cylinder 2, and the oil on the bottom side is connected to the oil passage on the tank 7 side. Returned to. Therefore, the lift cylinder 2 operates in the direction in which the rod is contracted, whereby the earthwork plate 1 rises. Similarly, when each of the operation valves 4, 5, 13 is switched from the neutral position to another position, the discharge oil from the pump 12 passes through each oil passage and operates the cylinder, so that the earthwork plate 1 responds accordingly. Change the position. In such a circuit A, according to claim 1, a floating position is provided on both sides of the tilt operation valve 5, and a head side oil passage 6a reaching the tilt cylinder 3 and a bottom side circuit 6b are respectively called return side circuits 8a, 8b. Suction valves 9 and 9 which are connected to each other and are capable of sucking from the tank 7 when the return side oil passages 8a and 8b are insufficient.

Next, the operation will be described. When the back leveling work shown in FIG. 7 is performed, conventionally, since the earthmoving plate 1 moves in the tilt direction with respect to the unevenness of the road surface, it is necessary to correct the horizontal posture of the earthworking plate 1 each time. It was However, in the present invention, since the floating position is provided next to the left and right tilt positions, the lift operation valve 4 and the tilt operation valve 5 are provided as shown in the operation pattern of the lift-tilt lever in FIG. If both are placed in the floating position, the movement in the tilt direction will be automatically corrected by the floating. It should be noted that the switching between the left and right floats may be determined according to the state of the unevenness of the road surface.

According to the second aspect of the present invention, as shown in FIGS. 3 and 4, the tilt operation valve 5 of FIG. ) 14, a separate switching valve 15 is provided. Therefore, the same parts as those in FIG. 1 shown in FIG. 3 are designated by the same reference numerals as those in FIG. 1, and the description thereof will be omitted. That is, a switching valve 15 having two positions of neutral and floating is provided between the oil passages 6a and 6b. The switching valve 15 is switched from the neutral position to the floating position by turning on the switch 17 using the battery 16 as a power source. The switching valve 18 of FIG. 4 shows another embodiment of FIG. 3, and the switching valve 15 of FIG. 3 is switched by the operation of the switch 17, whereas it is manually switched.

[0013]

[Effect of the device]

 As described above, the present invention provides a hydraulic circuit for a working machine including at least a lift operation valve and a tilt operation valve for operating each work machine cylinder such as a bulldozer earthwork plate. The tilt operation valve is provided with a floating position, and the oil passage from the tilt operation valve to the tilt cylinder and the oil passage to the tank are connected to each other, and the oil passage from the tank is connected to each oil passage on the connected tank side. A suction valve capable of sucking the oil is provided, and in claim 2, the oil passage from the tilt operation valve to the tilt cylinder and the circuit to the tank are connected to each other, and each oil passage on the tank side is connected. A suction valve that allows suction from the tank was installed, and a switching valve with two positions, neutral and floating, was installed between both oil passages, so that the tilt also floats during the leveling work during back leveling. Status Will be obtained, work is easy, yet finish also becomes good.

[Brief description of drawings]

FIG. 1A shows an embodiment of a hydraulic circuit of a working machine according to claim 1 of the present invention and a side surface of an earthworking machine to which the hydraulic circuit is connected, and FIG. 1B shows the earthworking machine part of FIG. It is explanatory drawing which shows a plane.

FIG. 2 is an explanatory view showing a lift-tilt operation pattern in FIG.

FIG. 3 (a) shows an embodiment of a hydraulic circuit of a working machine according to claim 2 of the present invention and a side surface of an earthworking machine to which the hydraulic circuit is connected. (B) of the earthworking machine part of (a) It is explanatory drawing which shows a plane.

FIG. 4 is an explanatory view showing another embodiment of the switching valve according to claim 2;

FIG. 5A is an explanatory diagram showing a hydraulic circuit of a conventional working machine and a side surface of an earthworking machine to which the hydraulic circuit is connected, and FIG. 5B is a plan view of the earthworking machine portion of FIG.

FIG. 6 is an explanatory view showing an operation pattern of a conventional lift-tilt lever.

FIG. 7 is an explanatory diagram showing a state of a conventional back leveling / laying operation.

[Explanation of symbols]

 1 Earthwork Plate 2 Lift Cylinder 3 Tilt Cylinder 4 Lift Operation Valve 5 Tilt Operation Valve 6a, 6b Oil Path 7 Tank 8a, 8b Oil Path 9 Suction Valve 14 Tilt Operation Valve 15 Switching Valve 18〃 A Hydraulic Circuit

Claims (2)

[Scope of utility model registration request] 1. In a hydraulic circuit of a working machine having at least a lift operating valve and a tilt operating valve for operating each working machine cylinder such as an earthwork plate of a bulldozer, a floating position is provided for the tilt operating valve. At the same time, the oil passage from the tilt operation valve to the tilt cylinder and the oil passage to the tank are connected to each other, and a suction valve that allows suction from the tank is provided in each of the connected circuits on the tank side. The hydraulic circuit of the working machine. 2. In a hydraulic circuit of a working machine including at least a lift control valve and a tilt control valve for operating each cylinder of a work machine such as an earthwork plate of a bulldozer, the tilt control valve is changed to a tilt cylinder. The circuit leading to the tank and the oil passage leading to the tank are connected to each other, and a suction valve capable of sucking from the tank is provided in each of the connected oil passages on the tank side. A hydraulic circuit for a working machine, comprising a switching valve having a position.