JPH02146235A - Control method for tractive characteristics for construction machine - Google Patents

Abstract

PURPOSE:To positively obtain desired tractive force in a simple manner by detecting both tractive force and sprocket wheel speeds, operating the target tractive force based on the result of the detected value, and thereby concurrently obtaining final tractive force based on the target tractive force and the target sprocket wheel speed. CONSTITUTION:An operator 1 operates a torque converter speed ratio, a torque factor, a torque ratio, tractive force and sprocket wheel speeds (theoretical vehicle speed=sprocket wheel speed) based on engine revolutions Ne and the output revolutions Nf of a torque converter. The speed V' which will be of a throttle command, is operated based on tractive force Fve and vehicle speeds Vsp by means of a control target diagram 2. In addition, a throttle command value Wcon corresponding to tractive force Fve is obtained by means of an engine output command map 3 based on the speed V'' while will be of a throttle command having passed through gain 4, and the aforesaid value is concurrently inputted to an engine as a final throttle command Wset. In this case, a specified correction value Wh is added to the throttle command Wcon.

Description

[Detailed description of the invention] Industrial application field: The present invention has a torque converter in the engine output system,
The present invention relates to a method for controlling the traction characteristics of a construction machine such as a bulldozer equipped with dosing, ripping, etc. working equipment.

Conventional technology and its challenges The motion of construction machinery such as nibble dozers involves transmitting engine output to sprocket wheels through power lines such as torque converters, transmissions, bevel gears, horizontal shafts, steering clutches, steering brakes, final reduction gears, etc. This is done by driving a crawler track wrapped around a sprocket wheel. Therefore, the traction force generated in the belly band can be accurately calculated based on the engine output and the reduction ratio of the power line.

The engine output of construction machinery such as bulldozers is set to the required value by manual operation using the main control lever.The engine output set with this main control lever is destroyed by stepping on the deceleration pedal, and the deceleration pedal is returned to its original state. Restores the required output set to .

During movement of the bulldozer, when the traction force exceeds the frictional force between the tracks and the ground surface, the tracks slip on the ground, resulting in a so-called crawler slipping condition. When this crawler track slipping occurs, the bulldozer's engine output is not effectively utilized as traction force, resulting in not only energy loss but also unavoidable problems such as abnormal wear of the track. For this reason, conventionally, when track slippage occurs, the operator senses this and depresses the deceleration pedal to reduce engine output, reducing the sprocket rotation speed (vehicle speed) and eliminating the track slippage.

In such conventional technology, the traction characteristics are determined by the settings at the time of design of the engine → torque converter → power line. Traction characteristics are dominated by traction force (substantially equal to load) and vehicle speed characteristics. Therefore, it was not possible to set arbitrary traction characteristics without operating the deceleration pedal by the operator.

Means for Solving the Problem: The present invention sets the traction characteristics of a construction machine to any suitable traction characteristics that correspond to the movement of the construction machine itself or the work content of the work equipment, and allows the machine to operate with the traction characteristics selected by the operator. It allows movement. For this reason,
In the present invention, by automatically controlling the engine output, it is possible to set the desired traction characteristics depending on the characteristics of the torque converter, and by simply selecting the traction characteristics suited to the various work conditions, the deceleration pedal can be activated. The target traction force can be obtained without any operation.

Structure and operation of the invention: In the method of the present invention, in order to generate a traction force suitable for work through the power line, the traction force and the sprocket vehicle speed are related to each other depending on the time change rate of the input/output rotation ratio of the torque converter. By paying attention to the fact that the sprocket speed varies, it is possible to obtain a suitable traction force that corresponds to the required sprocket vehicle speed.

This means that a traction force for smoothly operating a work load or a working machine can be obtained depending on changes in the output of the torque converter within a range that does not cause crawler track slippage.

That is, the present invention detects the engine rotation speed and the torque converter output rotation speed, calculates the torque converter speed ratio, torque coefficient, and torque ratio to develop traction characteristics suitable for driving or working on construction machinery. Detect the force and sprocket vehicle speed; Introduce this detected value of sprocket vehicle speed into a control target diagram consisting of speed vs. traction force to calculate the target traction force; Next, calculate the torque converter characteristics using speed as a parameter. The target traction force is obtained by calculating the throttle command by introducing a suitable target traction force and detected values of sprocket vehicle speed into the throttle command-traction force diagram based on the throttle command.

In addition, a correction value of the throttle command calculated from the pump absorption torque and regulation gradient suitable for the target work of the work equipment is added to this throttle command to obtain the final throttle command, and the target traction force is obtained by this command. This improves the precision of the control of traction characteristics.

Furthermore, substantially the same effect can be obtained by multiplying the throttle command by a preset correction factor to obtain the final throttle command and obtaining the target traction force using this command.

In this way, it is possible to set an arbitrary traction characteristic corresponding to the load condition, and it is also possible to change or select the traction characteristic according to fluctuations in work.

Embodiment: Hereinafter, a specific embodiment of the present invention will be described based on the drawings. The block diagram in FIG. 1 shows one embodiment of this. The detected values of the engine rotation speed Ne, ) torque converter output rotation speed Nt are input to the calculator 1 together with the vehicle speed signal, and the torque comparator 1Vr motor speed ratio, torque coefficient, torque ratio, traction force, and vehicle speed are calculated. Traction force Fve and theoretical vehicle speed (sprocket vehicle speed) Vsp are output. On the other hand, a control target diagram 2 consisting of speed and traction force is set. As illustrated in Figure 2, this control target diagram 2 shows the relationship between the speed of the construction machine and the traction force F, and when the engine output is at full stroke, it mainly shows the full performance curve shown by the broken line. It has become. The point where this full performance curve of engine output intersects with the Y-axis indicating speed is the upper limit of vehicle speed, and the point where it intersects with the X-axis indicating traction force is the upper limit of traction force. but,
The maximum effective traction force of a construction machine with tracks is obtained when the shoe slip ratio is constant. Therefore, when the soil and rock quality becomes hard, the traction force and vehicle speed including this element become the basic engine output mode, which tends to be shown by the line cut off the high output part of the full performance curve in Figure 2. ing. V.

and Fo are the vehicle speed and traction force that serve as the origin of the fundamental mode diagram. The traction forces Fve and Vsp outputted from the arithmetic unit 1 are introduced into the control target diagram 2 consisting of the speed-traction force obtained in this way, and the speed zo which becomes the throttle command is calculated and output. This speed zo is converted into zo via gain 4 or feedforward, and then introduced into the engine output command map 3. Map 3 for obtaining this engine output command is a map consisting of a throttle command-traction force diagram having various torque converter characteristic curves as shown in FIG. A throttle command Wcon corresponding to the force Fve is obtained. This throttle command Wcon can be output to the engine as substantially the final throttle command Wset.

Furthermore, the pump absorption torque Tρ is calculated by multiplying the auxiliary pump pressure that follows the target work of the work equipment by the pump discharge amount, and the regulation gradient is based on the average ratio of this value and the engine rotation speed (=torque converter input rotation speed) Ne. A correction value Wh of the throttle command is calculated.

Then, the above correction value Wh is added to the throttle command Wcon.
is added and output to the engine as the final throttle command Wset, making it possible to smoothly control the motion of the construction machine and the behavior of the work machine.

The correction value wh of this throttle command is the throttle command −
For CQII, it can be expressed as Wh=α×con. The correction factor α at this time is 0.1 to 0.2 in this embodiment, and a preferable operating state can be obtained within this range. Therefore, the final throttle command -5
et can be expressed as Wset=a'XWcon, and the final correction factor l in this case is 1.1~
1.2 is an appropriate value. Then, the correction addition value based on this correction factor or the final correction factor may be incorporated in advance into each operation of the collar lever, so that it is automatically expressed with the operation of the lever.

Effects of the Invention: According to the method of the present invention, reliable shoe slip control is possible, ensuring economical operation of construction machinery and preventing abnormal wear of tracks. In addition, arbitrary handling performance can be achieved, and efficient processing power can be obtained for a variety of work situations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a specific embodiment of the present invention. 2 is a control target diagram in FIG. 1, and FIG. 3 is a map for determining the engine characteristics in FIG. 1.

Claims (1)

[Claims] 1. The engine output system has a torque converter, and the engine output is transmitted to the sprocket wheel by a power line such as the torque converter, horizontal shaft, steering clutch, steering brake, final reduction gear, etc. to drive the crawler track. In construction machinery that is driven and equipped with work equipment: Detects the engine rotation speed and torque converter output rotation speed, and calculates the torque converter speed ratio, torque coefficient,
The torque ratio is calculated to detect the traction force and the sprocket vehicle speed; this detected value of the sprocket vehicle speed is introduced into a control target diagram consisting of speed and traction force to calculate the target speed; then, the speed is set as a parameter. The target traction force is obtained by calculating the throttle command by introducing a suitable target traction force and detected values of sprocket vehicle speed into the throttle command-traction force diagram based on the torque converter characteristics. Traction characteristics control method for featured construction machinery. 2. To the throttle command calculated in the throttle command-traction force diagram according to claim 1; by adding a correction value of the throttle command calculated from the pump absorption torque and regulation gradient suitable for the target work of the work equipment. A method for controlling traction characteristics in construction machinery, characterized in that a final throttle command is used, and a target traction force is obtained by this command. 3. The throttle command calculated in the throttle command-traction force diagram according to claim 1 is multiplied by a preset correction factor to obtain the final throttle command, and the target traction force is obtained by this command. A method for controlling traction characteristics in construction machinery characterized by;