JPH01310134A - Controlling method in start based on shoe slip - Google Patents

Abstract

PURPOSE:To dispense with the operation of controlling the degradation of function and efficiency of a working machine with a deceleration pedal by converting a speed mode from a stationary speed mode to a transient speed mode in starting while beginning an operation and returning the speed mode to the stationary one after the starting. CONSTITUTION:In a tractive force of an engine-speed diagram, assuming the tractive force in the origin of stationary speed mode is Fo and the speed is Vo, the tractive force in the origin of transient speed mode is Fs and the speed is Vo. The shoe slip rate detected in the start of a bulldozer is low and a load is low, so that the vehicle speed is naturally increased. For example, in the case of ripping, the inclusion property of the ripper is degraded or time taken for the inclusion is increased. Then, in the start of the bulldozer or the like, the output mode of the engine is downgraded once and the output of the engine is returned gradually in a certain time to the stationary speed mode. By such constitution in the operational start is dispensed with the operation of controlling the engine output with a decelerator pedal to prevent the degradation of function and efficiency of the bulldozer.

Description

[Detailed Description of the Invention] Industrial Application Field: The present invention prevents excessive vehicle speed when starting the vehicle when operating a tracked vehicle such as a large bulldozer that has working equipment for dozing, ripping, etc. The present invention relates to a method of controlling engine output at the time of starting so that the working operation of a working machine can be started smoothly.

Conventional technology The motion of a tracked vehicle such as a nibbledozer is achieved by transmitting engine output to the sprocket wheel through power lines such as a torque converter, transmission, bevel gear, steering clutch, steering brake, and final reduction gear. This is done by driving a wound crawler track. Therefore, the traction force on the crawler track can be calculated from the engine output and the reduction ratio of the power line.

The engine output of a tracked vehicle is set to the required value by manual operation using the main control lever.The engine output set by the main control lever is reduced by depressing the deceleration pedal, and is set by releasing the deceleration pedal. The required output is restored.

The traction force during operation of a tracked vehicle is related to the shoe slip ratio that occurs between the track and the ground.The larger the shoe slip ratio is, the more traction power is produced, but there is a limit, and if the shoe slip ratio is exceeded, the shoe slip ratio increases. However, the tracked vehicle's engine output is not effectively used as traction force, resulting in not only energy loss but also FL damage such as short-term wear of the track.

Conventionally, when excessive juice slip occurs, the operator senses this and depresses the deceleration pedal to reduce engine output, and at the same time operates the work equipment to reduce the load and reduce the traction force. , the shoe slip was resolved.

When the shoe slip is resolved, it is necessary to release or return the deceleration pedal to its original state and return the engine output to a preset steady state output.

Section M to be solved: Shoe slip control by operator operations is performed by the operator recognizing the occurrence of shoe slip visually and sensually, and by reducing the load by operating the work equipment and cutting off the engine output by operating the deceleration pedal. . Therefore, the operation by the operator is complicated and requires careful attention, and the difference depending on the operator's briquettes has a large influence. Even in the case of a skilled operator, it is unavoidable that there is a time lag between the occurrence of a shoe slip and the operator's operation, and some operators often cause unnecessary slips, resulting in a shoe slip. It is difficult to achieve the purpose of preventing this from occurring. Therefore, when operating at a steady speed or an approximate speed, a standard shoe slip rate is set in advance to prevent shoe slip during various situations during operation. Detect rate. On the other hand, multiple output modes are set for the engine output, and the engine output is automatically cut off or restored in response to fluctuations in the shoe slip ratio, allowing optimal work operation without the need to operate the deceleration pedal. It is possible. This method of controlling the engine output mode based on the shoe slip rate is suitable for performing work operation while maintaining a steady speed, but it is suitable for performing work operation while maintaining a steady speed. Control was difficult in the case of transient speeds.

Means for Solving the Problem: The present invention proposes a means for solving the above-mentioned problems.The present invention temporarily suppresses the engine output to prevent the vehicle speed from increasing too much at the time of starting, and reduces the speed of the work equipment that starts when the vehicle starts. This is a control method that allows work functions to be fully utilized. That is, when starting, if the engine output mode is at a steady speed, the vehicle speed will automatically increase, and for example, the ripper may not penetrate properly. In such a situation, the engine output mode is temporarily lowered only when the vehicle starts, thereby preventing the vehicle from increasing too fast immediately after the vehicle starts, thereby preventing the above-mentioned disadvantages.

Structure and operation of the invention: In the present invention, a tracked vehicle such as a large bulldozer that has working equipment for dozing, ripping, etc. is equipped with an actual vehicle speed detection mechanism to detect the actual vehicle speed when shoe slip occurs. . At the same time, the theoretical vehicle speed and engine speed are detected.

Theoretical vehicle speed can be calculated from the output rotation speed of the torque converter, the shoe slip rate can be calculated from the theoretical vehicle speed and the actual vehicle speed, and the traction force can be calculated from the output rotation speed of the torque converter and the engine rotation speed.

In order to automatically increase engine output or cut off engine output using each of these factors, create an engine output mode that adapts to each work operation state in the engine towing car speed diagram, and set these This can be done by selecting the engine output mode.

In other words, as illustrated in Fig. 1, the engine output state, so-called steady speed, is achieved by cutting off the high output part depending on the soil or rock quality of the work target compared to the full output curve in the engine towing car speed diagram. modes (including a basic mode for obtaining an adaptive shoe slip rate and a control mode in which engine output is cut off to return to the set value when the shoe slip rate exceeds the set value). Furthermore, when the vehicle starts in the steady speed mode, a transient speed mode is provided in which the engine output is reduced to prevent an increase in vehicle speed. In FIG. 1, if the traction force at the origin on the steady speed mode is Fo and the speed is Vo, then in the transient speed mode, the traction force corresponding to the origin is F9 (velocity is V).

Since the shoe slip ratio detected when a bulldozer or the like starts is low and the load is low, the vehicle speed naturally increases, and in the case of ripping, for example, the ripper's penetration becomes poor or the time required for the ripper to bite becomes longer. Therefore, the state of operation, behavior, etc. when starting a bulldozer or the like is detected, the engine output mode is temporarily lowered at the time of starting, and the engine output is gradually returned to the steady speed mode within a certain period of time.

Specifically, the method of the present invention is applied when performing a work operation such as bulldozer climbing: When the engine output is maintained at a steady state with the high output part of the full output curve shown in the towing car speed diagram representing the engine output state. Establish a speed mode and a transient speed mode in which the engine output is reduced; when starting while starting work with the work equipment, detect this starting state and convert from the steady speed mode to the transient speed mode and temporarily reduce the engine output. The main idea is to lower the mode to prevent excessive vehicle speed when starting; after starting, the engine output should be gradually increased within a certain period of time to return to steady speed mode;
By performing such control, it is almost unnecessary for the operator to operate the deceleration pedal.

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

For example, when operating a tracked vehicle such as a large bulldozer that has working equipment for dozing, ripping, etc., when looking at the relationship between the traction force F and the vehicle speed V, as shown in Figure 1, when the engine is at full output, is like the full output curve shown by the broken line. The point where this engine full output curve intersects with the X-axis indicating speed is the upper limit of vehicle speed, and the point where this engine full output curve intersects with the Y-axis indicating traction force is the upper limit of traction force.

However, as described above, the traction force of a tracked vehicle is related to the shoe slip ratio, and the maximum effective traction force is obtained when the shoe slip ratio is constant. Therefore, the traction force including this element, the vehicle speed, and the operation of the work equipment are inseparably related, and as the soil and rock quality becomes harder, the line obtained by cutting the high output part of the full output curve in Figure 1 It is shown in steady speed mode where the engine output is shown as . In this steady speed mode, the engine output is reduced and the vehicle speed is slightly reduced →
When a transient speed mode corresponding to low speed → medium speed → steady speed is established, the traction force F corresponding to the origin of the steady speed mode is
and the traction force F, which corresponds to the origin of the transient speed mode, so that the speed does not become excessive ■. It is possible to temporarily reduce the output while maintaining the engine speed, and then set the timer to gradually return the engine output mode to normal speed.

In this example, it is assumed that the bulldozer starts the ripping operation when it starts, and the shoe slip rate, which is the reference for controlling the operation at this time, is set to 30%. In addition, the initial setting value during this work operation is that the traction force is 50 tons (F
oe, and the steady speed was 0.7 kIl/h.

When the ripper is lowered and the vehicle is started, this state is detected and the engine output is reduced to the transient speed mode, which corresponds to 60% of the steady speed mode. I can do it. If the engine output is to be reduced to prevent the vehicle speed from increasing excessively, a timer linked to the output mode down switch can be used for a certain period of time (preferably about 1 to 3 seconds, and in this example it was set to 3 seconds). I increased the engine output to steady speed mode.

This series of control at the time of starting, which involves controlling the engine output, is performed by associating elements that satisfy the engine output or operating conditions of the work equipment with the ripper lever in advance as a calculation step as shown in FIG. It controls the engine output mode as well as the operation.

Although the above embodiment deals with ripping, it goes without saying that other embodiments such as dozing or shoveling can also be controlled in the same way.

Effects of the invention: The method of the present invention prevents deterioration of function and efficiency of the working equipment when starting work on a tracked vehicle such as a large bulldozer that has working equipment for dozing, ripping, etc. Lost.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of engine output mode control at the time of starting based on a towing car speed diagram showing the engine output mode, Figure 2
The figure shows a calculation step when starting work. Applicant Komatsu Manufacturing Co., Ltd. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. When a tracked vehicle such as a large bulldozer equipped with various working machines starts and performs work operation using the working machines; A steady speed mode with engine output that cuts the high output part and a transient speed mode with reduced engine output are established; when starting while starting work with the work equipment, this starting state is detected and the machine changes from the above steady speed mode. The system converts to transient speed mode and temporarily lowers the engine output mode to prevent excessive vehicle speed when starting; after starting, the engine output is gradually increased within a certain period of time to return to steady speed mode; A control method at the time of starting based on shoe slip characterized by the following.