JPH06257603A - Hydraulic driving control system - Google Patents

Abstract

PURPOSE:To prevent erroneous operation of a working machine and secure safety of operation, which error may be caused by abnormality in electric lever or a harness system. CONSTITUTION:A timer means 1 starts counting specified time at the same time of application of a main switch. A monitor means 2 monitors the signals of levers, and judges whether or not they are at neutral positions. When the lever signal indicates that it is out of the neutral position, the condition is notified to an output control means 3. The output control means 3 cancels an output voltage when the output voltage of the lever signal indicates that it is out of the neutral position before the specified time passes, and inhibits solenoid current to be output to a solenoid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control system used for construction machines and the like driven by hydraulic actuators.

[0002]

2. Description of the Related Art In hydraulically driven machines such as power shovels and bulldozers, a lever signal corresponding to an operation amount of an electric lever operated by an operator is detected, and a controller outputs a solenoid current proportional to the lever signal to each solenoid. By doing so, the operation of the hydraulic actuator is controlled.

The output voltage of the lever signal and the solenoid current are set to have a relationship as shown in FIG. The output voltage of the electric lever is proportional to the lever position, and a voltage from 0 to Vcc is output according to the lever position. When the lever is in the neutral position, the output voltage is near Vcc / 2 (neutral range), and when the output voltage is in this range, the solenoid current does not flow. On the other hand, when the lever is out of the neutral position, that is, when the lever is operated by the operator, the solenoid current A or B flows to the corresponding solenoid, and the hydraulic actuator operates.

[0004]

Normally, when the lever is in the neutral position, the solenoid current does not flow, so that the operation of the working machine is stopped. However, if there is a displacement or abnormality of the electric lever, or if there is a contact failure in the lever signal harness system, contact with the vehicle body power supply or vehicle body ground, etc., the output voltage goes out of the neutral range and the operator operates it. The work machine may start to move even if it is not done. In particular, a malfunction immediately after the main switch is turned on has a high risk and causes an accident.

It is an object of the present invention to provide a hydraulic drive control system capable of preventing a malfunction of a working machine caused by a displacement of an electric lever or the like and ensuring work safety.

[0006]

In order to solve the above problems, in a hydraulic drive control system according to the present invention, an electric lever, a hydraulic actuator connected to a hydraulic source,
A control valve provided in an oil supply / discharge passage from a hydraulic source to a hydraulic actuator for controlling the oil flow rate, a solenoid for driving the control valve, and a solenoid current proportional to the operation amount of the electric lever are output to the solenoid. In a hydraulic drive control system having a controller, a timer means for starting timing of a predetermined time at the time of turning on a main switch, a monitoring means for monitoring whether an output voltage of a lever signal is in a neutral range, and the predetermined time. If the output voltage deviates from the neutral range before the time elapses, output control means for prohibiting the output of the solenoid current to the solenoid is provided.

[0007]

[Operation] A predetermined time after the main switch is turned on,
Whether the electric lever is in the neutral position is monitored, and if the output voltage of the lever signal goes out of the neutral range before the predetermined time has elapsed, the output voltage is treated as invalid and the solenoid current solenoid Output to.
According to this, even if the output voltage of the lever signal goes out of the neutral range due to a failure or some other reason, the work machine is not operated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic drive control system according to the present invention will be described below with reference to the drawings.

FIG. 2 is a circuit diagram showing the basic configuration of the hydraulic drive control system according to the present invention. This system includes an electric lever 11, a controller 12, and a drive unit 13.

The electric lever 11 is a manual operation means operated by an operator, and a lever signal corresponding to the operation amount of the lever is sent to the controller 12.

The controller 12 includes an A / D converter 14,
A CPU (central processing unit) 15, a D / A converter 16, and an amplifier 17 are used to detect the lever signal of the electric lever 11 and to calculate the solenoid current proportional to the output voltage of the lever signal based on the relationship shown in FIG. It is generated and output to the drive unit 13.

FIG. 1 is a block diagram showing the functional structure of the controller 12 for controlling the output of the solenoid current when the main switch is turned on. In FIG. 1, the timer means 1 starts counting a predetermined time when the main switch is turned on, and when the predetermined time has elapsed, notifies the output control means 3 of this. The monitoring means 2 monitors whether or not the output voltage of the lever signal sent from the electric lever 11 is in the neutral range, and when the lever signal is out of the neutral range, notifies the output control means 3 of this. To do.
The output control means 3 prohibits the output of the solenoid current when the monitoring means 2 notifies that the lever signal is out of the neutral range before the predetermined time has elapsed. These timer means 1, monitoring means 2 and output control means 3 are CPUs.
It is realized by a circuit having 15 as a main part.

The drive unit 13 is provided in a hydraulic actuator 18 connected to the working machine, a pump 19 for supplying hydraulic pressure to the hydraulic actuator 18, a hydraulic actuator 18 and an oil supply / discharge passage of the pump 19, and controls the oil flow rate. Control valve 20 and solenoid 2 for driving the control valve 20
It is composed of 1. The solenoid 21 is composed of a set of A and B, and is controlled by a solenoid current output from the controller 12. For example, the solenoid current A in FIG. 4 is output to the solenoid A, and the solenoid current B is output to the solenoid B.

In FIG. 2, the operator operates the electric lever 1
When 1 is operated, the lever signal corresponding to the operation amount is CP
It is detected at U15. The CPU 15 executes a process based on a flowchart described later, and outputs a solenoid current proportional to the lever signal to the solenoid 21 of the drive unit 13 through the amplifier 17.

Next, the processing procedure for controlling the output of the solenoid current when the main switch is turned on will be described with reference to the flowchart of FIG.

First, when the main switch is turned on, the timer means 1 starts measuring the time T (step 10).
1). The monitoring means 2 accepts the input of the lever signal (step 102), judges whether all the lever signals are in the neutral zone (step 103), and when the lever signals are out of the neutral zone, the output control means 3 To notify. The output control means 3 determines whether or not the elapse of the time T has been notified by the timer means 1 (step 104), and the time T
When has passed, the routine proceeds to a normal control routine (step 105). If the time T has not elapsed, the output of the solenoid current is prohibited (step 10).
6).

The lever signal is input after the main switch is turned on, and the lever signal before the main switch is turned on is input when the main switch is turned on. In the above-described system, the solenoid current of the solenoid current is changed in both cases. Output can be prohibited.

[0018]

As described above, in the hydraulic drive control system according to the present invention, all the lever signals input are monitored for a predetermined time after the main switch is turned on, and the lever signals are out of the neutral range. In this case, since the solenoid current output is prohibited, even if the lever signal is erroneously input due to an abnormality in the electric lever or an abnormality in the harness system within a predetermined time after the main switch is turned on, the work machine does not operate. As a result, malfunctions can be prevented in advance. Further, even when the operator accidentally operates the lever and turns on the main switch to start the engine, the operation of the working machine can be prohibited. In this way, the danger of the working machine starting to move against the operator's intention immediately after the main switch is turned on is avoided, so that the safety of work can be ensured.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration for controlling output of a solenoid current when a main switch is turned on.

FIG. 2 is a circuit diagram showing a basic configuration of a hydraulic drive control system.

FIG. 3 is a flowchart showing a processing procedure for controlling output of a solenoid current when the main switch is turned on.

FIG. 4 is a diagram showing a relationship between an output voltage of a lever signal and a solenoid current.

[Explanation of symbols]

1 ... Timer means, 2 ... Monitoring means, 3 ... Output control means, 1
1 ... electric lever, 12 ... controller, 13 ... driving unit,
15 ... CPU, 18 ... Hydraulic actuator, 21 ... Solenoid

Claims (1)

[Claims] 1. A manual operation means, a hydraulic actuator connected to a hydraulic source, a control valve provided in an oil supply / discharge passage from the hydraulic source to the hydraulic actuator, for controlling an oil flow rate, and driving the control valve. In a hydraulic drive control system having a valve drive means for controlling and a controller for outputting a drive signal proportional to the operation amount of the manual operation means to the valve drive means, a timing means for measuring a predetermined time when the main switch is turned on, and a manual operation means Monitoring means for monitoring whether or not the input position of the operating means is in a predetermined neutral range, and prohibiting the output of the drive signal if the input position deviates from the neutral range before the predetermined time elapses A hydraulic drive control system comprising: output control means;