JPH0370051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a dossing device such as an earth removal plate in a bulldozer.

[Conventional technology]

A bulldozer is a wheel-type or crawler-type traveling machine equipped with a dozing device such as an earth removal plate so that it can be raised and lowered, and is used to excavate and move soil, for example.
When excavating the ground to a specified reference plane,
If the dozing device is lowered and held so that the lower end of the dozing device is at a predetermined height position with respect to the traveling body, and the traveling body is moved forward, the amount of soil increases on the front side of the dossing device.

It is known, for example, in Japanese Patent Laid-Open No. 52-137102, to detect the load applied to the dozing device and automatically control the lifting and lowering of the dozing device.

On the other hand, it is desired to maintain the vertical height position of the earth dozing device substantially constant with respect to the reference plane of earth excavation or earth dossing in order to improve the efficiency of ground preparation work. In order to respond to this demand, the special public interest in prior art
In Publication No. 1081, the light flux emitted from a fixed point separate from the bulldozer's traveling body, such as a support on the ground, is set to be constant with respect to a reference plane, and the light beam attached to the bulldozer's earth removal plate is set to be constant with respect to a reference plane. It is proposed that the light flux be detected by a detector to control the movement of the earth removal plate in the vertical direction.

[Problem to be solved by the invention]

However, if the direction of the bulldozer changes,
The installation position and orientation of the light beam irradiation device must be changed, which is extremely troublesome. Further, even if the above-mentioned luminous flux detection is performed, it is not possible to measure (detect) the amount by which the bulldozer slips and the traveling crawler sinks below the reference plane on soft ground. Then, if the amount of settlement is larger than necessary, accidents such as the vehicle becoming unable to run may occur, and the efficiency of land preparation work is significantly reduced.

The present invention aims to solve the above technical problem.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a dosing device such as a dosing plate, which is movable up and down with respect to a reference surface of the dosing material by a double-acting hydraulic cylinder attached to a traveling machine. With the control mechanism that controls the vertical movement of
The dosing device is controlled to move up and down in a direction that cancels out the increase or decrease in load applied to the dosing device, and a subsidence sensor is installed on the traveling body to detect the amount of subsidence of the lower surface of the traveling crawler with respect to the reference surface. is provided, and the set value of the amount of settlement is adjustable, and if the traveling crawler sinks below the reference surface by more than a certain level, the dozing device is controlled to be operated to raise preferentially based on the detection signal of the settlement sensor. It is something.

〔Example〕

Next, an explanation will be given based on an example of the present invention.
In the figure, reference numeral 1 indicates a pair of left and right traveling crawlers 2,
2 shows a traveling aircraft mounted on a truck frame 3 equipped with a truck frame 3. The rear of the traveling aircraft 1 is equipped with a control seat 4, and the front of the traveling aircraft is equipped with an engine 5, which transmits the power to drive sprockets 6, 6 of traveling crawlers 2, 2, and drives a hydraulic pump 7. .

Reference numeral 8 designates a dossing device which is provided in front of the traveling crawlers 2, 2 so as to be able to rise and lower with respect to the traveling body 1, and the dossing device 8 has its rear end pivoted to the track frame 3 by pin 9, A pair of left and right C frames 10, 10 protruding toward the front of the aircraft;
It consists of a dirt removal plate 11 attached to the front ends of frames 10, 10, and is slidable through vertically penetrating each of a pair of left and right double-acting hydraulic cylinders 12, 12, which are pivotally connected to the front side of the traveling body 1. The lower ends of the piston rods 13, 13 are pivotally connected to the earth removal plate 11, and oil is supplied from the hydraulic pump 7 to the upper chamber 15 or lower chamber 1 of the hydraulic cylinder 12 via a hydraulic circuit 14, which will be described later.
6 to drive the dozing device 8 up and down.

Switching valve 17 in the hydraulic circuit 14 shown in FIG.
is a 4-port, 3-position, 2-solenoid coil, spring center type electromagnetic switching valve. At the first offset position, port P communicates with port A, port R communicates with port B, and the hydraulic Hydraulic pressure from the pump 7 is sent to the upper chamber 15 of the hydraulic cylinder 12 through the passage 18, and oil from the lower chamber 16 is returned to the oil tank 20 through the passage 19, thereby lowering the earth removal plate.

At neutral position B, connect PR and connect ports A and B.
are both occluded. The passage 18 to the upper chamber 15 and the passage 19 to the lower chamber 16 are connected to an unload valve 21 that can freely adjust the set pressure, so a load is applied to the front surface of the earth removal plate 11. Then, the pressure in the upper chamber 15 of the hydraulic cylinder 12 returns to the lower chamber 16 via the unload valve 21, and the earth removal plate 1
1 by an appropriate size.

At the second offset position C, ports A and R are in communication, the oil in the upper chamber 15 of the hydraulic cylinder returns to the hydraulic tank 20, and ports P and B are in communication.
The hydraulic pressure of the hydraulic pump 7 acts on the lower chamber to remove the soil from the earth removal plate 11.
to rise.

Each position of the switching valve 17 is controlled by a detection device 22 and a control mechanism 23, as shown in FIG. That is, instead of directly detecting the vertical height position of the lower end of the earth removal plate 11 with respect to the reference surface 24 of earth excavation or dossing with a bulldozer, the detection device 22 detects the relative position of the earth removal plate 11 and the hydraulic cylinder 12. ,
For example, a differential transformer or a potentiometer is installed that can detect the amount of movement of the piston rod 13 in the hydraulic cylinder 12 relative to the hydraulic cylinder 12.

While converting the signal from this detection device 22 into an electric signal by a converter 25, a target value 27 is input in advance to a setting unit 26 such as a potentiometer that sets the position at which the lower end of the earth removal plate 11 is lowered to the reference surface 24. The output signal of this setting section 26 and the converter 2
The comparison unit 28 compares the measured signal obtained by the comparison unit 28 with the measurement signal obtained by the comparison unit 28, and if the difference is greater than a certain value, the electromagnetic valve 29 is driven in accordance with the output signal of the comparison unit 28, and the switching valve 17 is operated.

When the measured value is larger than the target value by a certain amount, that is, when the lower end of the earth removal plate 11 is a certain distance above the reference plane 24, the switching valve 12 is switched to the first offset position A, and the earth removal plate 11 is set as the reference. Lower to surface 24.

On the other hand, if the measured value is smaller than the target value by a certain amount, that is, if the lower end of the earth removal plate 11 is below the reference surface 24 by more than a certain distance, the switching valve 17 is switched to the second offset position C, and the earth is removed. The plate is raised to the reference plane 24. If it substantially coincides with the reference plane, the switching valve 17 is set to the neutral position RO.

Then, for the traveling aircraft 1 etc., with respect to the reference plane 24,
A subsidence sensor 30 is provided which operates when the lower surface of the traveling crawler 3 subsides by more than a set value, and this control operation causes a limit switch 31 to operate so as to operate the solenoid valve 29, and the switching valve 17 to the second offset position C. The earth removal plate 11 is raised to reduce the load applied thereto.

In this configuration, first, the setting unit 26 is adjusted to set the target value 27 so that the lower end of the earth removal plate 11 substantially coincides with the reference position, and the unloading valve 21 is also adjusted.
Set the pressure. In this state, when the control mechanism 23 is set to "automatic" and the earth removal plate 11 is lowered, its lower end substantially coincides with the reference surface 24, and the switching valve 17 is placed in the neutral position B. When dozing work is started, if the resistance of the soil in front of the earth removal plate 11 becomes greater than the set value in the upper chamber 15 of the hydraulic cylinder 12, the oil will flow to the lower chamber 16 via the unload valve 21 and move the piston rod 13 upward. and pull up the earth removal plate 11. When the earth removal plate 11 is displaced upward and the displacement becomes greater than a certain deviation from the target value 27, the solenoid valve 29 is operated via the comparison section 28, and the switching valve 17 is moved to the first offset position A. Then, the oil from the hydraulic pump 7 is sent to the upper chamber 15 of the hydraulic cylinder 12 to displace the earth removal plate 11 in the downward direction. By repeating this process, earth excavation or land leveling work can be performed on 24 substantially uniform reference surfaces.

Then, in the set pressure state of the unload valve 21,
During dossing work, if the load on the front surface of the earth removal plate 11 is too large and the traveling crawler 2 slips, scraping the ground and causing the traveling machine 1 to sink more than a certain level with respect to the reference surface 24, the above-mentioned Subsidence sensor 3
0 is preferentially activated, the switching valve 17 is returned to the second offset position C, and the earth removal plate 11 is raised, thereby preventing the main body of the bulldozer 1 from sinking due to slipping and the burying of the traveling crawler 2 portion. .

Furthermore, the setting value of the amount of subsidence of the lower surface of the traveling crawler 2 with respect to the reference surface 24 can be changed.
If the subsidence sensor 30 is configured to have variable sensitivity adjustment, or the vertical mounting position of the subsidence sensor 30 with respect to the traveling aircraft is configured to be vertically adjustable by remote control from the control unit, it is possible to easily adjust the vertical movement on soft ground etc. When the traveling machine is likely to slip, by setting the sensitivity of the subsidence sensor to be sensitive, etc., the worker can be made aware of the rise of the earth removal plate more quickly, and it is possible to easily prevent the traveling machine from being buried. Further, the sensitivity of the subsidence sensor 30 as described above is configured to be variable, or the vertical position of the subsidence sensor 30 is variably adjustable, and the subsidence sensor 30 is controlled by the target value setting section 26 or the control mechanism 23. If it is related to the comparison section 28 (see the dashed line in FIG. 2),
This has the effect of making it easier to set the reference plane depending on the soil quality, such as soft or hard ground.

[Operation and effects of the invention]

In summary, the present invention uses a control mechanism that operates a double-acting hydraulic cylinder for raising and lowering a dozing device to raise and lower the dozing device in a direction that negates the increase or decrease in the load applied to the dozing device. In the process of control, the amount of subsidence of the lower surface of the traveling crawler relative to the reference surface of the dosing material can be detected by a subsidence sensor, and if the amount of subsidence exceeds a certain level, the dosing device is activated preferentially in the upward direction. Therefore, it is possible to prevent an accident in which the traveling crawler sinks into the ground and becomes unable to travel on soft ground.

In addition, since the set value of the amount of subsidence is adjustable, such as by configuring this subsidence sensor so that its sensitivity can be adjusted freely, or by configuring the vertical mounting position of the subsidence sensor with respect to the traveling aircraft to be freely adjustable, it is possible to adjust the set value of the amount of subsidence. It becomes easy to set the reference plane according to the soil quality. Therefore, it is possible to reliably control the load of the dossing device and its vertical position with respect to the reference plane, and it is also possible to further improve the efficiency of scraping work and dossing work by a bulldozer.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a side view of a bulldozer, and FIG. 2 is a schematic system diagram of a control device. 1... Traveling aircraft, 2... Traveling crawler, 7...
Hydraulic pump, 8... Dossing device, 10... C frame, 11... Earth removal plate, 12... Double acting hydraulic cylinder, 13... Piston rod, 14... Hydraulic circuit, 17... Switching valve, 21 ...Unload valve, 2
2... Detection device, 23... Control mechanism, 28... Comparison section, 29... Solenoid valve, 30... Subsidence sensor.

Claims (1)

[Claims] 1. A dossing device such as an earth removal plate is provided so that it can be raised and lowered with respect to the reference surface of the dossing material using a double-acting hydraulic cylinder attached to the traveling machine body, and a control mechanism that controls the lifting and lowering movement of the earth dozing device is provided. Depending on the increase or decrease of the load on the dozing equipment,
While controlling the dozing device to move up and down in a direction that cancels out this increase/decrease, the traveling body is equipped with a settlement sensor that detects the amount of settlement of the lower surface of the traveling crawler with respect to the reference surface, and the set value of the amount of settlement can be adjusted. Control of a dozing device in a bulldozer, characterized in that if the traveling crawler sinks below the reference plane by a certain amount or more, the dozing device is controlled to be raised preferentially based on a detection signal from a subsidence sensor. Device.