JPH0830428B2 - Method for controlling traction characteristics of construction machinery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for controlling traction characteristics in a construction machine such as a bulldozer having a torque converter in an engine output system and equipped with a working machine such as dozing and ripping. It is related.

Conventional technology and its problems: The motion of construction machinery such as a bulldozer is the output of the engine,
It is performed by transmitting power to a sprocket wheel through a power line such as a torque converter, a transmission, a bevel gear, a horizontal shaft, a steering clutch, a steering brake, and a final reduction gear, and driving a crawler belt wound around the sprocket wheel. Therefore, the traction force generated in the crawler belt can be accurately calculated from the engine output and the reduction ratio of the power line.

The engine output of construction machines such as bulldozers is set to the required value by manual operation by the main control lever, and the engine output set by this main control lever is reduced by depressing the deceleration pedal. Restore the required output set.

When the pulling force exceeds the frictional force between the track and the ground contact surface during exercise of the bulldozer, the track slips on the ground,
So-called track slippage occurs. When this track slippage occurs, the engine output of the bulldozer is not effectively utilized as a traction force, and not only energy loss but also trouble such as abnormal wear of the track is inevitable. For this reason, when crawler belt slippage occurs, the operator conventionally senses it and depresses the deceleration pedal to reduce the engine output, thereby reducing the sprocket rotation speed (vehicle speed) and eliminating the crawler belt slippage.

In such a conventional technique, the traction characteristic is determined by the setting at the time of designing the engine → torque converter → power line.
The traction characteristics are governed by the traction force (substantially equal to the load) and the vehicle speed characteristics. Therefore, it is impossible to set an arbitrary traction characteristic without operating the deceleration pedal by the operator.

The present invention has been made in view of the above circumstances, and sets the traction characteristics of the construction machine to any characteristics corresponding to the movement of the construction machine itself or the work content of the working machine,
It is an object of the present invention to provide a traction characteristic control method for a construction machine, which is capable of operating the machine with a traction characteristic selected by an operator.

Means and Actions for Solving the Problems: In the present invention, in order to develop a traction force suitable for work through the power line, the traction force and the sprocket vehicle speed are mutually changed by the input / output rotational speed of the torque converter depending on the temporal change rate. It is possible to obtain a suitable traction force corresponding to the required sprocket vehicle speed, paying attention to the fact that it fluctuates while being related. This means that due to the change in the output of the torque converter, a traction force for smoothly performing the work target load or the operation of the work machine, etc. is obtained within a range in which crawler belt slip does not occur.

In short, the traction characteristic control method for a construction machine according to the present invention is a construction machine in which engine output is transmitted to a sprocket wheel via a torque converter, and the traction characteristic of the construction machine is represented by a speed-traction force line representing an output state of the engine. A method for controlling a traction characteristic of a construction machine in which an arbitrary control target diagram inside a full output curve in the figure is controlled. The method includes detecting an engine speed and a torque converter output speed, and determining a torque converter speed ratio and a torque coefficient. And the torque ratio are calculated to obtain the traction force and the sprocket vehicle speed, the traction force is introduced into the control target diagram in the speed-traction force diagram to calculate the target speed, and then the target speed and the traction force are calculated. , Throttle command based on torque converter characteristics with target speed as parameter Was introduced into attraction diagram is characterized in that to obtain the traction force as a target by calculating the throttle command.

According to the present invention, it is possible to set an arbitrary traction characteristic corresponding to a load state, and only by selecting a traction characteristic adapted to various work situations, a target traction force can be obtained without operating the deceleration pedal. Can be obtained.

In the present invention, a final throttle command is obtained by adding a correction value corresponding to the absorption torque of the work machine pump to the throttle command obtained from the throttle command-traction force diagram, and the target traction is determined by this final throttle command. It is preferable to obtain a force in order to improve the accuracy of control of the traction characteristics.

Example: Hereinafter, a specific example of the present invention will be described with reference to the drawings. The block diagram of FIG. 1 shows this embodiment. Engine speed Ne, torque converter output speed
Each detected value of Nt is input to the calculator 1 together with the vehicle speed signal, and the torque converter speed ratio, torque coefficient, torque ratio, traction force, vehicle speed are calculated, and the 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-traction force is set. As shown in FIG. 2, this control target diagram 2 shows the relationship between the speed V of the construction machine and the traction force F, and when the engine output is a full stroke, it mainly shows a full performance curve shown by a broken line. Has become. The point at which the full performance curve of the engine output intersects the Y axis indicating speed is the upper limit of vehicle speed, and the point at which the full performance curve intersects the X axis indicating traction force is the upper limit of traction force. However, as for the traction force of the construction machine having the crawler belt, the effective maximum traction force is obtained when the shoe slip ratio is constant. Therefore, the traction force including this factor and the vehicle speed will be the engine output basic mode that tends to be shown by the line with the high output part cut in the full performance curve of Fig. 2 as the soil and rock quality become harder. ing. Vo and Fo are the vehicle speed and traction force that are the origin of the basic mode diagram. The control target line diagram 2 composed of the speed-traction force thus obtained is shown in FIG. 2 and the traction force _Fve and the sprocket vehicle speed V output from the arithmetic unit 1 described above.
Introduce _sp to calculate and output the target velocity V '. This target speed V ′ is introduced into the engine output command map 3 after being converted to V ″ by passing through the gain 4 or being feed-forwarded.
Is a throttle command having various torque converter characteristic curves with V ″ as a parameter as shown in FIG.
A suitable torque converter characteristic is selected from the map consisting of the traction force diagram to obtain the throttle command Wcon corresponding to the traction force Fve. This throttle command Wcon can be substantially output to the engine as the final throttle command Wset.

Further, in order to add a correction value corresponding to the absorption torque of the work machine pump, the pump absorption torque T _p is calculated by multiplying the pump discharge that follows the target work of the work machine by the pump discharge amount. It is preferable to multiply T _p by the reciprocal of the regulation gradient to calculate the throttle command correction value W _h , and add this correction value W _h to the above-mentioned throttle command W _con to obtain the final throttle command W _set. is there. By doing so, it becomes possible to control the motion of the construction machine and the behavior of the work machine with higher accuracy and smoothly.

As another embodiment, an embodiment in which a preset correction factor is multiplied to obtain the throttle command correction value W _h and the final throttle command W _set is also possible. That is, the correction value Wh of this throttle command can be expressed as Wh = α × Wcon with respect to the throttle command Wcon. The correction rate α at this time is 0.1 to 0.2 in this embodiment, and a preferable operating condition is obtained in this range. Therefore, the final throttle command Wset can be expressed by Wset = α ′ × Wcon, and the final correction factor α ′ in this case is 1.1 to
1.2 is an appropriate value. Then, the correction addition value based on the correction rate or the final correction rate may be incorporated in advance in each operation of the ripper lever so as to be automatically expressed as the lever is operated.

Effects of the Invention: According to the method of the present invention, reliable shoe slip control is possible, and economical operation of a construction machine is ensured and abnormal wear of a crawler belt is prevented. Also, any traction performance can be realized, and efficient processing power can be obtained for various work situations.

[Brief description of drawings]

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

Claims (2)

[Claims] 1. In a construction machine for transmitting engine output to a sprocket wheel through a torque converter, the traction characteristic of the construction machine is inside a full output curve in a speed-traction force diagram representing an output state of the engine. A method for controlling a traction characteristic of a construction machine for controlling to an arbitrary control target diagram, which detects an engine speed and an output speed of a torque converter, and calculates a torque converter speed ratio, a torque coefficient and a torque ratio to draw a traction force. Then, the sprocket vehicle speed is obtained, this traction force is introduced into the control target diagram in the speed-traction force diagram to calculate the target speed, and then the target speed and the traction force are used as a parameter of the torque converter. Throttle command based on characteristics-Calculate throttle command by introducing into traction diagram A method of controlling a traction characteristic of a construction machine, characterized in that a target traction force is thereby obtained. 2. A final throttle command is obtained by adding a correction value corresponding to the absorption torque of the working machine pump to the throttle command obtained from the throttle command-traction force diagram, and the final throttle command is set as a target. The traction characteristic control method for a construction machine according to claim 1, wherein a traction force is obtained.