JPH0823318B2 - Control method when tracked vehicle is in three-point contact state - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tracked vehicle such as a bulldozer capable of performing ripping work as well as dozing, and the tracked vehicle is mounted on both sides of the tip of the ripper and the front part of the vehicle body during the ripping operation. The present invention relates to a control method in a three-point grounding state of a tracked vehicle that controls an engine output so that a vehicle speed that allows normal ripping is achieved when a grounding state is established at three points with each local portion of a track. .

Conventional technology: The engine output of a tracked vehicle is set to the required value by manually operating the throttle lever that performs the main control. The engine output set by this throttle lever is reduced by depressing the deceleration pedal to the deceleration pedal. If you return to the original, the required output set will be restored.

The setting of the throttle lever is usually set to the engine output required for the work when moving forward. However, the work operation of a large bulldozer must be adjusted to an appropriate value by varying the engine output depending on the work subject such as earth and sand in various states or hard and soft rock, or the work content such as dozing or ripping. I won't.

On the other hand, in the ripping work of turning up a concrete roadbed or breaking up a rock bed by the work of a bulldozer, the work load changes greatly and it is necessary to keep the engine output at an appropriate value each time. Therefore, the set position of the throttle lever that is suitable for work in a steady state during forward movement does not match the desired set position for engine output that can cope with load changes during ripping work, and therefore the deceleration pedal should be operated during load changes during ripping. Had to use.

Problems to be solved: During forward movement in normal work operation, the shoe slip control by the operator's operation allows the operator to visually and sensually recognize the occurrence of shoe slip, reduce the load by operating the work machine, and operate the engine output by operating the deceleration pedal. The cut-off and is done by. Therefore, the operator's operation is complicated and requires careful attention, and the difference depending on the skill of the operator has a great influence. Even in the case of a trained operator, it is inevitable that a time lag will occur between the occurrence of shoe slip and the operator's operation, and some operators often slip unnecessarily, so that shoe slip can be prevented. The purpose of prevention is difficult to achieve.

Especially during the ripping work, the rear part of the car body comes up without hitting the hard rocks by the ripper, and the car body is grounded and supported at two points on each side of the track (closer to the front) and the tip of the ripper. In many cases, a so-called three-point claw state occurs.
In this state, the apparent load is reduced, the vehicle speed is increased more than necessary, and the ripper is prevented from being stuck in the rock bed or stuck in the rock bed. Therefore, unless the operator operates the deceleration pedal to cut the engine output, it is impossible to escape from the three-point grounded state.

SUMMARY OF THE INVENTION The present invention aims to solve such a problem by performing a ripping work operation under the control of automatically cutting off and releasing the engine output according to the shoe slip ratio and the traction force. In a tracked vehicle in which a three-point grounding condition due to the inability of the ripper to bite into hard rock is rapidly eliminated and a smooth transition to steady operation can be achieved without operating the deceleration pedal. It is to provide a control method in a point grounding state.

Means and Actions for Solving the Problems: In order to achieve the above-mentioned object, a control method according to the present invention when a tracked vehicle is in a three-point contact state is such that the tracked vehicle is operated during the ripping operation of the tracked vehicle. 3-point grounding state of a tracked vehicle that controls the engine output so that the vehicle speed is such that normal ripping is possible when the grounding state is reached at the 3 points of the tip of the ripper and each local part of the track on both sides of the front of the vehicle The control method at the time, the basic mode that cuts the high output part of the engine full output curve in the engine traction-theoretical speed diagram, and the three-point grounding that reduces the engine output to this basic mode When the state-resolving mode is set and stored in the output control system, and that the three-point ground contact state during work operation is detected by the number of vehicle body acceleration amplitudes exceeding a predetermined value, It is characterized in that the control output is controlled to shift from the basic mode to the three-point grounded state elimination mode.

In the present invention, for example, in a tracked vehicle such as a bulldozer having a working machine such as dozing or ripping, the actual vehicle speed when shoe slip occurs is detected, and at the same time, from the engine speed and the output speed of the torque converter. The theoretical vehicle speed obtained is detected. Further, the shoe slip ratio is calculated from the theoretical vehicle speed and the actual vehicle speed, and the traction force is calculated from the theoretical vehicle speed and the engine speed. To automatically cut off the engine output or increase the engine output using each of these factors,
This is performed by setting an engine output mode adapted to each work operation state in the engine traction-theoretical velocity diagram and selecting these engine output modes.
That is, with respect to the full output curve in the engine traction-theoretical velocity diagram, the basic mode is set which is the engine output state in which the high output portion is cut according to the soil or rock quality to be worked. Further, when a hard rock is encountered during the ripping work and the tracked vehicle comes into contact with the tip of the ripper and each local part of the crawler tracks on the front of the vehicle body at three points, the increase in vehicle speed is suppressed. Therefore, the three-point grounding state elimination mode in which the engine output is reduced is set. In this way, when the number of times that the acceleration amplitude of the tracked vehicle such as a bulldozer exceeds the predetermined value (acceleration amplitude during steady operation) reaches the predetermined number of times, the engine output shifts from the basic mode to the three-point grounding state elimination mode. By performing such control, it is possible to quickly cancel the three-point ground contact state and shift to steady operation without the need to depress the deceleration pedal. In addition, if the deviation of the acceleration at the time of 3-point ground contact from the acceleration during normal operation is preset in the vehicle speed setting dial for 3-point ground contact according to the soil or rock condition, It is possible to control the engine output to eliminate the three-point ground contact condition by just dialing.

Example: A specific example of the method of the present invention will be described below.

For example, in working operation of a tracked vehicle such as a large bulldozer having a working machine such as dozing and ripping, looking at the relationship between the traction force F and the vehicle speed V, as shown in FIG. At that time, it becomes like the full output curve shown by the broken line. The point at which the full output curve of this engine intersects with the X axis indicating speed is the upper limit of vehicle speed, and the point at which it intersects with the Y axis indicating tractive force is the upper limit of tractive force. However, as described above, the traction force of the tracked vehicle is related to the shoe slip ratio, and the effective maximum traction force is obtained when the shoe slip ratio is constant. Therefore, the traction force and vehicle speed including this element are the engine output that tends to be shown by the line with the high output part cut off in the full output curve of Fig. 1 as the soil and rock quality become harder. It is set as a mode.

The bulldozer is performing ripping work with the engine output in the basic mode, and the shoe slip ratio, which is the basis of various controls for this work operation, was set to 30%. Also, the traction force is the initial setting value during this work operation.
20 tons, steady speed was 1.3km / h.

This work operation is performed in the engine output mode represented by the basic mode in the traction force-velocity diagram shown in FIG. Then, when the hard rock is encountered during the ripping and the ripper does not bite into it, and the tip of the ripper projects on the hard rock surface to form a three-point contact state, the acceleration that originally balances with the basic mode causes a deviation.

At the same time, the acceleration amplitude becomes wider than in the basic mode. FIG. 2 shows this state, in which the acceleration g deviates as the time t elapses. A certain time range △
The maximum-minimum at tn is the amplitude D Gn (n is an integer such as 1 or 2).

When the acceleration amplitude shown in FIG. 2 continues for a predetermined number of times, a signal is issued to bring down the engine output mode in FIG. 1 from the basic mode to the cancellation mode capable of canceling the three-point ground contact condition. In FIG. 1, F _T represents the traction force that is the origin of the three-point grounding state elimination mode. In this embodiment, the above signal is emitted when the acceleration amplitude exceeding the reference value continues eight times.

This series of behaviors is such that elements satisfying each work condition are preset in the dial as the operation steps illustrated in FIG. 3 and associated with the switch, and when these switches are operated and the three-point grounding state is established, the engine is It controls the output.

Effect of the Invention: The method of the present invention uses a basic mode determined based on the shoe slip ratio in the traction force-velocity diagram of an engine to determine the three-point ground contact state that occurs during the ripping operation of a tracked vehicle, particularly a large bulldozer. It was possible to control as a standard. As a result, the depressing operation of the deceleration pedal can be eliminated or the number of deceleration operations can be kept to a very small number as in the case of steady work operation, which reduces the burden on the operator and is highly industrially applicable.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of engine output mode control in a three-point ground contact state based on a traction force-speed diagram showing an engine output mode, FIG. 2 is an explanatory diagram of acceleration amplitude and its frequency, and FIG. 3 is three points. It is a figure which shows the calculation step at the time of a grounding state.

Claims (1)

[Claims] 1. Normal ripping is possible when the tracked vehicle is in a state of contacting the ground at three points of the tip of the ripper and each of the crawler tracks on both sides of the front part of the vehicle body during the ripping operation of the tracked vehicle. This is a control method for controlling the engine output so that the vehicle speed will be constant when the tracked vehicle is in a three-point ground contact state, where the high output part of the engine full output curve in the engine traction-theoretical speed diagram is cut. A basic mode and a three-point grounding state elimination mode in which the engine output is reduced for this basic mode are set and stored in the output control system. When detected by the number of acceleration amplitudes of the vehicle body that exceeds the limit, the engine output is controlled so as to shift from the basic mode to the three-point ground contact elimination mode. Control method at the time of state.