JP2509311B2 - Work machine control method for construction machinery - Google Patents

Description

Description: INDUSTRIAL APPLICABILITY The present invention enables various operations without drive shock by avoiding the generation of linear drive hydraulic pressure when running a construction machine or operating a work machine. And a method for controlling a construction machine including modulation.

Conventional technology: Large construction machines such as power shovels, shovel dozers, and bulldozers are equipped with work machines adapted to various kinds of work, and are mainly operated by hydraulic drive. In hydraulic movement, the pressure oil pressurized by the plunger pump is sent to the upper or lower side of the piston of the hydraulic cylinder,
Move the work implement connected to the piston rod of the hydraulic cylinder. Various kinds of work are controlled by moving the spool of the operation valve in the pressure oil piping system with the lever of the driver's cab and switching the flow of pressure oil. The hydraulic piping system includes a pressure control valve that prevents the pressure oil from becoming excessively high pressure, a backflow prevention valve that prevents backflow when the circuit pressure of the pressure oil that was driving the work machine is lost, and a hydraulic cylinder. A vacuum prevention valve and the like that prevent the generation of a vacuum section are also installed inside.

With such a hydraulic drive mechanism, when moving a working machine or the like mounted on a construction machine, it is not possible to freely change the operating speed of a hydraulic valve represented by an operating valve and a pump variable device.

Problems to be Solved: In the hydraulic system of the related art, since the operation of the valve is performed at a constant speed, the input / output of the hydraulic pressure is linearly added, which causes various difficulties in driving operation. . That is, when the valve is actuated early, a shock is generated when the working machine is started and stopped. If the valve operates slowly, there will be a delay in starting and stopping the work machine. In addition, if there is an operation pattern that can change the speed of the same work machine in two or more ways, for example, if it has an excavation mode (normal speed mode) and a rehabilitation mode (1/2 speed mode) or a running high mode and a running low mode. In addition, it was unavoidable that the shock during operation was large in one mode and the operation was delayed in the other mode. In addition to the shock, cavitation occurred in the circuit when the variable pump device was actuated quickly.

Means for Solving the Problems: The method of the present invention has solved the above problems by installing a controller and operating the operating valve and the pump variable device via the controller. With such a control method, it is possible to prevent the operating states of the valve and the pump variable device from being changed instantaneously, and to give a time range to the expression of the driving force to the working machine, etc., and to prevent shock and cavitation from occurring smoothly. It became possible to perform various exercises. The control by the controller can be easily achieved by electrically performing.

Configuration / Operation of the Invention: In the method of the present invention, a power shovel, a shovel dozer,
A hydraulic control valve and a pump operated by a controller were used as a control valve and a pump variable device of a hydraulic piping system for moving a construction machine such as a bulldozer or moving a working machine equipped with the construction machine. The controller operates the valves and pumps so that the predetermined modulation is automatically controlled by the operator's electric lever operation, depending on the work situation or selected by the operator. Let

The modulation of valve actuation is shown in the diagram of FIG. The increase in stroke from the start of valve and pump variable device operation (when the stroke is min.) To the full stroke is a typical setting example where straight lines a and b are expressed at a constant rate with respect to time. In the conventional example, the response of A and B to the signal is shown with the system delay added.

This stroke is closely related to the circuit pressure, and the circuit pressure is max. At full stroke.

In the valve operating state in the method of the present invention, the rate at which the stroke changes with time is multistage, and the modulation patterns A, B, etc., which are shown by the curved lines, are set, and the settings are used differently depending on the conditions. . When the setting modulation A is applied to the input signal a, the output is A
Increase according to the setting. In the case of the setting modulation A with respect to the input signal b, since the input of b is slower than that of A, the output remains as b, and it operates slowly and no delay is felt during operation. In the case of the setting modulation B with respect to the input signal b, since b is input earlier than B, the output increases according to the setting of B.

Similarly, when the pressure is reduced from the full stroke, the valve is delayed when the input signal according to the conventional example is the straight line z, but in the method of the present invention, the valve is in the operating state represented by the modulation pattern Z. . Therefore, with respect to the signal input a, b, or z that becomes a straight line that changes at a constant rate, the stroke does not operate in any of the modulation patterns A, B, or Z earlier than the set time.

That is, the method of the present invention, when running a construction machine or moving an equipped work machine by hydraulic drive, includes: a hydraulic control in which an operation valve of a hydraulic piping system and a pump variable device are operated via a controller operated by an electric lever. As valves and pumps; the operating pressure and the pump circuit pressure increase / decrease and the pump discharge amount increase / decrease are such that the ratio of the operating time and the corresponding increase / decrease and increase / decrease is not constant, and changes sequentially in multiple stages. A command is issued from the controller so that the control valve and pump variable device operate so that they do not move faster than the set time when the circuit pressure of the hydraulic oil rises and falls at a constant rate with the operating time. A smooth valve operation and control of the pump are possible by performing a modulation action that absorbs the shock generated when the operation valve and the pump are operated. This is also a function to prevent cavitation of the circuit. Further, the modulation pattern can be arbitrarily used in a plurality of modes by instructing the controller to perform manual or automatic setting according to the work state. In addition, even when the construction machine is traveling, valve operation is performed with suitable modulation to enable traveling without shock over various speeds.

Example: Hereinafter, a specific example of the present invention will be described.

For example, as for a construction machine equipped with a crawler belt, which can be moved forward and backward and turned freely, equipped with a working machine such as a bucket, a tilt and a turning function, a hydraulic system as shown in the operation flow chart illustrated in FIG. Is provided. The hydraulic drive is pressurized by an oil pump driven by the engine of the construction machine, the pressure oil flow path is selected by valve operation, and the working machine moves. In the prior art, the spool of the operating valve was operated only by the work machine operating lever operated by the operator,
In the present invention, the controller is controlled by the electric lever, and the operation of the operation valve and the pump control device is kept slow. As a result, the circuit pressure of the pressure oil does not rise and fall at a constant rate over time, and the modulation action represented by the curved line is performed with a multi-step rate. Then, a signal is sent to the controller from a manual setting switch selected by the operator according to the state of the work and a mode change switch that automatically sets the work mode according to the condition. As a result, it is possible to have a plurality of modulation actions corresponding to various tasks.

Next, the working conditions and the setting of the modulation action will be described. Illustrated in FIG. 2 is an example with three sets of valve actuation modulations (at least two sets in the method of the invention).

In this case, the broken lines a, b, c, and z all indicate the state when the operation lever is operated. a is a quick operation, b
Is a normal operation, c is a slow operation, and z is an operation with a tendency similar to a. Among these, in the ascending mode of a and b (the descending mode of z), the occurrence of shock during operation is inevitable. This is conspicuous in the mode of "a" which tends to become a full stroke instantaneously. It should be noted that when the slow operation of c is performed, the ascending mode of reaching the full stroke is inherently slow, so no shock is felt, and the lever operation represented by c can be substantially the modulation pattern C.

The modulation patterns corresponding to these can be obtained by automatically setting according to each work mode or by instructing the controller by the manual setting of the operator and instructing the operation valve and the pump variable device section from the controller. Looking at the modulation patterns A and B illustrated in FIG. 2, for example, in the case of a power shovel work mode, for excavation, a modulation pattern of B that is shock-free and soft behavior is suitable for heavy excavation, For the correction, the modulation pattern of A, which has no delay in accuracy, is suitable. Also, when traveling,
A modulation pattern with no delay is preferable at low speeds, and a modulation pattern of B with less shock is preferable at high speeds to reduce the influence of inertia.

In formulating the modulation pattern in the present invention, in the operation of the operation valve or the operation of the variable device portion of the pump, an ineffective band (dead band) in the initial or final stage.
Through which the circuit pressure rises and a sufficient operating effect is obtained (in this embodiment, about 30
%) Holds the tendency to operate slowly.
These formulas can be controlled by operating an electric lever by incorporating an arithmetic circuit and a modulation selection command circuit in the controller.

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to effectively prevent shocks when the construction machine is running and when the working machine is started and stopped, and it is possible to suppress cavitation of the pump. By selecting a modulation pattern according to the work mode, it is possible to adapt to work that requires precision without delaying operation, or work that does not require precision but wants to proceed quickly without causing shock. It has become possible.

[Brief description of drawings]

FIG. 1 is a flow chart of a concrete embodiment of the method of the present invention, and FIG. 2 is an explanatory diagram of modulation patterns of an operation valve and a pump based on a command from a controller.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fujitoshi Takamura 3-1-1 Ueno, Hirakata-shi, Osaka Komatsu Ltd. Osaka factory (72) Inventor Toshio Yokoyama 3-chome, Ueno, Hirakata-shi, Osaka No. 1 Komatsu Ltd. Osaka factory

Claims (2)

(57) [Claims] 1. When hydraulically driving a construction machine or moving an equipped work machine: A hydraulic control valve for operating an operation valve of a hydraulic piping system and a variable pump via a controller operated by an electric lever. And a pump; such that the ratio of the operating time and the corresponding increase / decrease and increase / decrease in the operating pressure and the increase / decrease in the pump discharge amount due to the operation valve are not constant but change sequentially in multiple stages. Issue a command from the controller; Operate the control valve and pump variable device so that the circuit does not move faster than the set time when the circuit pressure of the hydraulic oil rises and falls at a constant rate over the operating time. A modulation function to absorb the shock generated when the operation valve and pump are operated, and to prevent cavitation generated when the pump is operated. A working machine control method for a construction machine characterized by the following. 2. In order to deal with various kinds of work, a plurality of operation modulations of an operation valve are provided, and a command of a controller governing the operation is automatically performed according to a work mode selected by an operator. The work machine control method for a construction machine according to claim 1, wherein the work machine control method according to claim 1 enables the operation modulation to be performed in any of various ways.