JPH09256419A - Control device for hydraulic construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work machine operation device capable of preventing the uncontrollable run of a hydraulic actuator, upon the occurrence of the stick of the control solenoid valve of a pilot e pipeline, and enhancing safety. SOLUTION: This device has a pair of operation buttons 10a and 10b for operating an offset cylinder 3d, pressure detectors 11a to 11c for detecting pilot pressure, a controller 12 electrically connected to the buttons 10a and 10b and the pressure detectors 11a to 11c, control solenoid proportional valves 13a to 13c and a shutout solenoid selector valve 13 electrically connected to the controller 12. When an OFF signal for closing the solenoid proportional valve 13b is outputted and pilot pressure detected with the pressure detector 11b is higher than the preset value, for example, a control signal is outputted from the controller 12 to close the solenoid selector valve 14, thereby shutting out a pilot oil feed pipeline 6 and returning a flow control valve 2d or the like to a neutral position. Furthermore. when an OFF signal for closing the other solenoid proportional valves 13a and 13c is outputted, the device also performs a similar operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a hydraulic construction machine such as a hydraulic excavator, and more particularly to a remote control type control device for remotely controlling a plurality of hydraulic actuators from a driver's cab.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, Japanese Patent Application Laid-Open Nos. 3-234956 and 4-216331, a control solenoid valve provided in a pilot line of a hydraulic device and an operating lever. Of a hydraulic construction machine having a remote control valve for outputting an electric signal corresponding to the operation amount of the operation lever, and a controller for outputting a control signal for operating the solenoid valve based on the electric signal. A control device has been proposed.

In such a conventional control device, when the operator grips the operation lever of the remote control valve and rotates the operation lever in a predetermined direction, an electric signal is output from the remote control valve in accordance with the operation amount. Since the signal is output and an ON signal is output from the controller based on this electric signal, the solenoid valve is opened, pilot oil is supplied to the hydraulic equipment, and the hydraulic equipment operates. Further, when the operator returns the operation lever to the initial neutral position, the output of the electric signal from the remote control valve is stopped, so that the controller outputs the OFF signal, the solenoid valve is closed, and the hydraulic device is stopped.

[0004]

By the way, in the above-mentioned conventional control device for a hydraulic construction machine, since an electric signal is output from the remote control valve through electric wiring, the periphery of the remote control valve is required. It is not necessary to dispose a pilot pipe in the part, and there is an advantage that the design and assembly around the remote control valve are relatively easy. However, in the unlikely event that the solenoid valve sticks due to the inclusion of foreign matter such as dust, when the operator returns the operation lever to the initial neutral position, the electromagnetic signal is output even if the controller outputs an OFF signal. Since the valve is kept open, there has been a concern that the hydraulic equipment may be operated erroneously against the operator's will, and the hydraulic actuator may run out of control.

The present invention has been made in view of the circumstances of the prior art as described above, and an object thereof is to provide a hydraulic actuator when a control solenoid valve provided in a pilot line of a hydraulic device causes a stick. To provide a control device for a hydraulic construction machine capable of preventing the runaway of the vehicle and improving safety.

[0006]

According to the present invention, a control solenoid valve is provided in a pilot line for guiding pilot oil from a pilot pump, and pressure detection is performed for detecting the pressure of pilot oil in the pilot line. And a shutoff solenoid valve for shutting off the pilot oil supply pipeline, and the shutoff solenoid valve is provided according to the output of a signal for closing the control solenoid valve and the detection result of the pilot pressure in the pilot pipeline. By closing the solenoid valve, the pilot oil supply pipeline is shut off.

According to the present invention thus constructed, when the control solenoid valve is stuck and is in the open state in spite of the output of the signal for closing the control solenoid valve provided in the pilot conduit, Since the pressure of the pilot oil in the pilot line is higher than a predetermined value, the pilot pressure is detected by the pressure detector and the shutoff solenoid valve is closed to shut off the pilot oil supply line. As a result, all the flow rate control valves are automatically returned to the neutral position, so that runaway of the hydraulic actuator can be prevented and safety can be improved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In a control device for a hydraulic construction machine of the present invention, a flow control valve for controlling the flow rate of hydraulic oil supplied to a hydraulic actuator and a pilot oil supplied from a pilot pump are used for the flow control valve. In a control device for a hydraulic construction machine, comprising: a pilot conduit that leads to the pressure receiving chamber of the control valve; and a control solenoid valve that is interposed in the pilot conduit and that operates in response to an electric signal, the control solenoid valve and the flow rate. Between the control valve and a pressure detector that detects the pilot pressure in the pilot pipe, a solenoid valve for shutting off the pilot oil supply pipe is provided, and the control solenoid valve is When the closing signal is output and the pilot pressure is higher than a predetermined value, the shutoff solenoid valve is closed to shut off the pilot oil supply line.

Further, in order to improve the operability of the attachment actuator provided in the work machine, a button type switch for operating the actuator and a controller for controlling the operation of the actuator flow control valve operated by the switch. And outputting a control signal for controlling the control solenoid valve from the controller based on an operation signal from the switch, and based on an operation signal from the switch and a pressure signal from the pressure detector. Another control signal for controlling the shutoff solenoid valve is output from the controller.

[0010]

Embodiments will be described with reference to the drawings.
1 is a hydraulic circuit diagram of a hydraulic excavator equipped with a control device for a hydraulic construction machine according to an embodiment of the present invention, FIG. 2 is a block diagram showing the overall configuration of the control device in FIG. 1, and FIG. It is a figure explaining operation | movement of a control apparatus.

In FIG. 1, 1a is a boom operation lever device, 1b is an arm operation lever device, 1c is a bucket operation lever device, 1d is an offset operation pedal device, 1e is a turning operation lever device, and 1f is a right side. The traveling operation lever device 1g is a left traveling operation lever device, and the operation lever devices 1a to 1c, the operation pedal device 1d, and the operation lever devices 1e to 1g are respectively arranged at predetermined positions in a driver's cab (not shown). . Reference numerals 2a to 2g denote flow rate control valves for controlling the flow rates of hydraulic oil supplied to the hydraulic actuators 3a to 3g, respectively.
Boom cylinder 3a and arm cylinder 3 out of 3g
b, the bucket cylinder 3c, and the offset cylinder 3d operate respective constituent parts of the working machine (not shown), the swing motor 3e swings a swing body (not shown), and the right traveling motor 3f and the left traveling motor 3g move the traveling body (not shown). Is designed to run. Also,
Reference numeral 4 is a main pump for supplying hydraulic oil to the flow control valves 2a to 2g, 5 is a pilot pump for supplying pilot oil through the pilot oil supply pipe 6, and 7a is a shuttle valve 8a.
The arm pushing pilot line for guiding the pilot oil to the pressure receiving chamber 2b ₁ of the arm flow rate control valve 2b via 7 and the right 7b for guiding the pilot oil to the pressure receiving chamber 2d ₁ of the offset flow rate control valve 2d via the shuttle valve 8b. An offset pilot conduit 7c is a left offset pilot conduit for guiding pilot oil to another pressure receiving chamber 2d ₂ of the offset flow control valve 2d via the shuttle valve 8c.
a to 7c and the like are branched from the pilot oil supply pipe line 6. In addition, the above-described operation lever devices 1a to 1c, 1e to
1g, and the operation pedal device 1d has a pressure reducing valve, and pilot pressure (primary pressure) supplied from the pilot pump 5
Is reduced in accordance with each operation amount, and the reduced pilot pressure (secondary pressure) is supplied to each of the flow rate control valves 2a to 2g.

The control device 9 of the present embodiment operates the offset cylinder 3d in two opposite directions, that is, in the extension direction and the contraction direction, respectively.
a, 10b and pressure detectors 11a, 11b, 11c,
These operation buttons 10a, 10b and pressure detectors 11a ...
The controller 12 electrically connected to the controller 11c, the control electromagnetic proportional valves 13a, 13b, 13c and the shutoff electromagnetic switching valve 14 electrically connected to the controller 12.
And The shutoff electromagnetic switching valve 14 is provided on the upstream side of the above-described operation lever devices 1a to 1c, 1e to 1g and the operation pedal device 1d, and supplies the pilot pressure (primary pressure) supplied from the pilot pump 5. , It is designed to shut off.

The pair of operation buttons 10a and 10b are turned on.
These push buttons are OFF switches, and these operation buttons 10a and 10b are provided, for example, on the grips of the operation lever devices 1a and 1c located on the right side in the driver's cab. The pressure detector 11a is interposed between the solenoid proportional valve 13a and the shuttle valve 8a to detect the pilot pressure in the arm pushing pilot pipe line 7a. Similarly, the pressure detector 11b includes the solenoid proportional valve 13b and the shuttle valve. It is installed between the valve 8b and the right offset pilot line 7b to detect the pilot pressure, and another pressure detector 11c is installed between the solenoid proportional valve 13c and the shuttle valve 8c, and is left offset. The pilot pressure in the pilot line 7c is detected.

As shown in FIG. 2, the controller 12
Is an input unit 1 for inputting operation signals from the operation buttons 10a and 10b, pressure signals from the pressure detectors 11a, 11b and 11c, and angle signals from a plurality of angle sensors (not shown).
2a and various calculations based on these operation signals, pressure signals and angle signals, and the pressure detector 1
A calculation unit 12b that determines whether or not the pilot pressure detected at 1a to 11c is higher than a predetermined value, and a solenoid proportional valve 13
a to 13c and control signals for controlling the electromagnetic switching valve 1
Output unit 12c for outputting other control signals for controlling
And Although a detailed description of the controller 12 is omitted, the controller 12 also has a function of determining whether or not the working machine is in a predetermined interference prevention area based on the angle signal, so that the working machine does not interfere. When entering the prevention area, the solenoid proportional valves 13a, 1
By opening 3b and performing an arm pushing operation or a right offset operation, the working machine is retracted from the interference prevention area.

Further, the solenoid proportional valves 13a to 13c are
The arm pushing pilot pipe 7a branched from the pilot oil supply pipe 6, the right offset pilot pipe 7b, and the left offset pilot pipe 7c are respectively provided,
When the pilot oil passes through both the solenoid proportional valve 13a and the operating lever device 1b, either one of the pilot oils having a high pressure will flow through the shuttle valve 8a and the flow control valve 2b.
Of the pressure receiving chamber 2b ₁ is adapted to be supplied preferentially, and when both the proportional solenoid valve 13b and operating pedal device 1d passes through the pilot oil, other proportional solenoid valves 13c and operating pedal device 1d The same applies when the pilot oil passes through both of the above. The electromagnetic switching valve 14 is provided in a pilot oil supply pipe line 6 that supplies pilot oil discharged from the pilot pump 5.

In such an embodiment, for example, when the operator grips the grip portion of the operating lever device 1a, 1c with the right hand and appropriately operates in the front-rear direction, a pilot pressure signal corresponding to the operation amount is used to output the boom control operating lever. The amount of pressure oil supplied from the device 1a to the flow control valve 2a and supplied to the boom cylinder 3a is controlled based on the pilot pressure signal. Similarly, when the operation lever devices 1a and 1c are appropriately operated in the lateral direction, the bucket control operation lever device 1
The amount of pressure oil supplied from the flow rate control valve 2c to the bucket cylinder 3c is controlled based on the pilot pressure signal output from c. Also, with the right finger, press the right operation button 10
By pressing a, the right offset operation signal from the operation button 10a is input to the input section 12a of the controller 12.
Is input to the right offset solenoid proportional valve 13b from the output section 12c, the pilot oil from the pilot oil supply line 6 is supplied to the solenoid proportional valve 13b, the shuttle valve 8b and the right. It is supplied to the pressure receiving chamber 2d ₁ of the flow rate control valve 2d via the offset pilot conduit 7b. As a result, the flow control valve 2d moves to the right in FIG. 1, so that the offset cylinder 3d extends and the right offset operation is performed.

Similarly, with the right finger, the left operation button 10b is formed.
By pressing, the left offset operation signal from the operation button 10b is input to the controller 12, the left offset electromagnetic proportional valve 13c is opened by the control of the controller 12, and the pilot oil supply conduit 6 is opened. The pilot oil flows through the solenoid proportional valve 13c, the shuttle valve 8c and the left offset pilot conduit 7c to the flow control valve 2
It is supplied to the pressure receiving chamber 2d _{2 of} d. As a result, the flow control valve 2d moves to the left in FIG. 1, so that the offset cylinder 3d contracts and the left offset operation is performed.

On the other hand, OF which closes the solenoid proportional valve 13b
When the electromagnetic proportional valve 13b is in the open state by sticking due to foreign matter being caught or the like despite the F signal being output, the pilot detected by the pressure detector 11b by the arithmetic unit 12b of the controller 12 It is determined that the pressure is higher than a predetermined value, a control signal is output from the output unit 12c, the electromagnetic switching valve 14 is closed, and the pilot oil supply pipe line 6 is shut off.

Therefore, actuator control is performed as shown in FIG. For example, if the operation button 10a is turned on when the solenoid proportional valve 13b is normal, the pressure detector 11
Since b detects H (high) pressure, the electromagnetic switching valve 14 does not operate, pilot oil is supplied, and the electromagnetic proportional valve 13b operates and opens, so that the offset cylinder 3d extends. After that, when the operation button 10a is turned off, the pressure detector 11b detects the L (low) pressure.
Although the solenoid operated directional control valve 14 does not operate and pilot oil is supplied, the offset cylinder 3d stops because the solenoid proportional valve 13b closes. On the other hand, when the operation button 10a is turned off when the solenoid proportional valve 13b is out of order, the pressure detector 1
1b detects H (high) pressure, so solenoid proportional valve 13b
Is determined to be a failure in the operating state, and the electromagnetic switching valve 14 is closed to shut off the pilot oil supply pipe line 6. As a result, all the flow rate control valves 2a to 2g are automatically returned to the neutral position, so the offset The cylinder 3d etc. stops. The same applies to the other solenoid proportional valves 13a and 13c.

In the above-described embodiment, when the solenoid proportional valves 13a to 13c are stuck due to foreign matter being caught, runaway of the arm cylinder 3b and the offset cylinder 3d can be prevented and the safety can be improved. .

Further, in the above embodiment, it is not necessary to operate the operation pedal device 1d when operating the offset cylinder 3d, and the operator can easily operate the operation buttons 10a and 10b by hand while maintaining a stable posture. Therefore, it is possible to improve operability when operating attachments such as offset.

In the above-described embodiment, the solenoid proportional valves 13a to 13c are provided as the control solenoid valves provided in the pilot conduits 7a to 7c, but the solenoid proportional valves 13a to 13c are replaced by electromagnetic solenoid valves. A switching valve may be provided, and the electromagnetic switching valve 14 is provided as a shutoff electromagnetic valve for shutting off the pilot oil supply pipe line 6. However, an electromagnetic proportional valve may be provided instead of the electromagnetic switching valve 14.

[0023]

As described above, according to the present invention,
If the control solenoid valve installed in the pilot line causes a stick, shutting off the shutoff solenoid valve shuts off the pilot oil supply line, and as a result all flow control valves are automatically returned to the neutral position. Therefore, runaway of the hydraulic actuator can be prevented, and therefore safety can be improved.

Further, since the button type switch for operating the hydraulic actuator and the controller for controlling the operation of the flow rate control valve for the actuator are provided, the attachments such as offsets provided on the working machine are operated by using the switch. In this case, the operator does not need to step on the operation pedal, and the operator can easily operate the operation button by hand while maintaining a stable posture, thus improving the operability when operating the attachments. You can

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic excavator including a control device for a hydraulic construction machine according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the overall configuration of the control device of FIG.

FIG. 3 is a diagram for explaining the operation of the control device of FIG. 1;

[Explanation of symbols]

1a~1c operating lever device 1d operating lever device 1e~1g control lever unit 2a~2g flow control valve 2b _1, 2d _1, 2d ₂ pressure receiving chamber 3a~3d cylinder (hydraulic actuator) 3E～3g motor (hydraulic actuator) 5 Pilot Pump 6 Pilot oil supply line 7a to 7c Pilot line 8a to 8c Shuttle valve 9 Control device 10a, 10b Operation button 11a to 11c Pressure detector 12 Controller 13a to 13c Electromagnetic proportional valve (controlling solenoid valve) 14 Electromagnetic switching valve (Solenoid valve for shutoff)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Iijima 650 Jinrachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura factory (72) Inventor Hiroshi Watanabe 650 Kintate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Ceremony Company Tsuchiura Factory (72) Hiroyuki Adachi Inventor Hiroyuki Adachi 650 Jinrachicho, Tsuchiura City, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Factory (72) Inventor Masakazu Haga 650 Kintachicho, Tsuchiura City, Ibaraki Hitachi Construction Machinery Co., Ltd. Inside the Tsuchiura Plant (72) Inventor Kazuhiro Shibamori 650 Kandamachi, Tsuchiura City, Ibaraki Prefecture Hitachi Construction Machinery Co., Ltd.

Claims (2)

[Claims] 1. A flow rate control valve for controlling a flow rate of hydraulic oil supplied to a hydraulic actuator, a pilot line for guiding pilot oil supplied from a pilot pump to a pressure receiving chamber of the flow rate control valve, and the pilot line. In a control device for a hydraulic construction machine, which includes a control solenoid valve that is interposed in the control solenoid valve and that operates according to an electric signal, between the control solenoid valve and the flow control valve, a pilot in the pilot pipeline A pressure detector for detecting pressure is provided, and a shutoff solenoid valve for shutting off the pilot oil supply pipe is provided, a signal for closing the control solenoid valve is output, and the pilot pressure is higher than a predetermined value. A control device for a hydraulic construction machine, characterized in that, when the temperature is high, the shutoff solenoid valve is closed to shut off the pilot oil supply pipeline. 2. A button type switch for operating the actuator according to claim 1, further comprising a controller for controlling the operation of an actuator flow control valve operated by the switch, and an operation signal from the switch. Based on the operation signal from the switch and the pressure signal from the pressure detector, while outputting a control signal for controlling the control solenoid valve from the controller based on A control device for a hydraulic construction machine, which outputs another control signal for controlling.