JP3277986B2 - Hydraulic construction work machine control device - Google Patents

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 work machine such as a hydraulic shovel, and more particularly to a control device for remotely controlling a plurality of hydraulic actuators in a cab.

[0002]

2. Description of the Related Art Conventionally, as a control device for a hydraulic construction machine, for example, Japanese Unexamined Patent Publication No. Hei 4-213631 has a remote control valve for outputting an electric signal corresponding to the operation amount of an operation lever. There has been proposed an invention in which a controller outputs a control signal for operating a control solenoid valve interposed in a pilot line of a hydraulic device based on the controller.

In this control device, when the driver grips the operating lever of the remote control valve and turns it in a predetermined direction, an electric signal corresponding to the operation amount is output from the remote control valve, and based on this electric signal, Since an ON signal is output from the controller, the solenoid valve is opened, the pilot oil is supplied to the hydraulic device, and the hydraulic device is driven. Also,
When the driver returns the operating lever to the initial neutral position, the remote control valve does not output an electric signal to open the solenoid valve, so the controller outputs an off signal, which closes the solenoid valve and stops the hydraulic actuator. The supply of pressure oil is cut off and the hydraulic equipment stops.

[0004]

As described above, in this control device for a hydraulic construction machine, an electric signal is output from a remote control valve via electric wiring.
There is no need to dispose a pilot pipe around the remote control valve, and there is an advantage that the design and assembly of the peripheral portion of the remote control valve are relatively easy. However, in the event that the solenoid valve becomes hard due to the intrusion of foreign matter such as dust, when the driver returns the operation lever to the initial neutral position, the off signal is output from the controller. However, since the solenoid valve is kept open, there is a danger that the hydraulic actuator will run out of control due to the continued supply of hydraulic oil to the hydraulic equipment against the driver's will.

The present invention has been made in view of such circumstances of the prior art, and an object of the present invention is to provide a hydraulic actuator even when a control solenoid valve interposed in a pilot line of a hydraulic device causes a heavy load. It is an object of the present invention to provide a control device for a hydraulic construction work machine, which can prevent runaway of a hydraulic construction machine with excellent safety.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a pilot line connected to a downstream side of a control solenoid valve interposed in a pilot line leading to a pressure receiving chamber of a directional control valve. A pressure detector for detecting the pilot pressure in the
A shut-off solenoid valve for interrupting the supply of the pie <br/> lot oil to the control solenoid valve by the drive current from the control device is provided, the control device is a drive current Tsu cross to close the control solenoid valve When
Said pilot pressure detected by a pressure detector from a point
Force measures the delay time until you drop below a predetermined value,
When the delay time has exceeded the proper operation time, the control device determines that control solenoid valve is abnormally operating,
Is obtained by outputs a drive current for you close the shut-off solenoid valve, preferably, the proper operating time control device is referred to when performing the operation determination of the control solenoid valve according to the temperature of the pilot oil The operation of the solenoid valve for control is determined according to the value of the appropriate operation time according to the temperature of the pilot oil detected by the temperature detector provided in the pilot line or the hydraulic oil supply line to the actuator. Is performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific examples will be described with reference to the drawings. FIG. 1 is a hydraulic circuit diagram of an entire hydraulic shovel according to a specific example of the present invention, FIG. 2 is a block diagram illustrating a configuration of a control device, and FIG. 3 is a diagram illustrating an operation state of the control device. 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 traveling operation. The 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 disposed at predetermined positions in a cab (not shown). Reference numerals 2a to 2g denote direction switching valves for controlling the direction and flow rate of hydraulic oil supplied to the hydraulic actuators 3a to 3g, respectively, and among the hydraulic actuators 3a to 3g, boom cylinders 3a,
The arm cylinder 3b, the bucket cylinder 3c, and the offset cylinder 3d actuate each mechanism element of the working machine (not shown), and the revolving body (not shown) is revolved by the revolving motor 3e, and is shown by the right traveling motor 3f and the left traveling motor 3g. It is designed to run a traveling body that does not.

Reference numeral 4 denotes a main pump for supplying hydraulic oil to the directional control valves 2a to 2g, and reference numeral 5 denotes a pilot pump for supplying pilot oil via a pilot oil supply pipe, and operation lever devices 1a to 1c and 1e. 1g and the operation pedal device 1d have a pressure reducing valve (not shown), and reduce the pilot pressure (primary pressure) supplied from the pilot pump 5 according to each operation amount. )
Is supplied to each of the direction switching valves 2a to 2g. T ₁ branch pilot oil supplied from the pilot pump 5 operating lever device 1a~1c, 1e~1g and leads to operating pedal apparatus 1d main pilot oil supply line, T ₂ from the main pilot oil supply pipe T ₁ Then, the pilot oil is supplied to the control electromagnetic proportional pressure reducing valves 13a, 13b,
13c is a sub-pilot oil supply pipe leading to 13c.

Further, T ₃ is an electromagnetic proportional pressure reducing valve 13 for control.
The pilot oil is supplied to the arm pressure receiving chamber 2b of the arm direction switching valve 2b through the shuttle valve 8a provided downstream of the arm 2a.
Arm pressing pilot lines leading to the _1, T ₄ is the shuttle valve provided downstream of the control solenoid proportional pressure reducing valve 13b 8b
Right offset pilot lines for guiding pilot oil to one of the pressure receiving chamber 2d ₁ of offset direction switching valve 2d via, T ₅ via a shuttle valve 8c provided downstream of the control solenoid proportional pressure reducing valve 13c Pilot the other left offset pilot lines leading to the pressure receiving chamber 2d ₂ of oil offset direction switching valve 2d to, T ₆ is control solenoid proportional pressure reducing valve 13
The detection pilot pipes are provided downstream of a, 13b, and 13c and communicate with each other via check valves 15a to 15c.

The control device 9 has a controller 12 shown in FIG. 2, and the controller 12 has the offset cylinder 3d in two opposite directions, ie, an extension direction and a contraction direction, as shown in FIG. DOO to a pair of switches 10a for operating respectively, and 10b, the pressure detector 11 and a temperature sensor 17 connected respectively to the detection pilot line T _6, not shown boom,
Angle sensors 16a, 16b, 16c respectively attached to the bending portions of the arm and the bucket to detect the turning angles α, β, γ of the bending portions, electromagnetic proportional pressure reducing valves 13a, 13b, 13c for control, Solenoid switching valve 14
Are electrically connected.

The pair of switches 10a and 10b are constituted by push-button switches for performing on / off operations, and are actually operating lever devices 1a and 1b located on the right side in the cab.
Is provided at the upper part of the grip portion, and in addition to the depressing operation of the operation pedal device 1d, the operation of expanding and contracting the offset cylinder 3d can be performed by pressing the pair of switches 10a and 10b. I have. The shutoff electromagnetic switching valve 14 is a control electromagnetic proportional pressure reducing valve 13a, 13b,
The pilot pressure (primary pressure) supplied from the pilot pump 5 is transmitted or cut off to the secondary side in accordance with a control signal from the controller 12.

A check valve 15a is interposed in a pilot line branched from a pilot line between the electromagnetic proportional pressure reducing valve 13a and the shuttle valve 8a, and a pilot valve between the electromagnetic proportional pressure reducing valve 13b and the shuttle valve 8b. A check valve 15b is interposed in the pilot line branched from the line, and a check valve 15c is interposed in the pilot line branched from the pilot line between the electromagnetic proportional pressure reducing valve 13c and the shuttle valve 8c. It has been, outflow side pilot oil of these check valves 15a~15c merges the detection pilot line T _6. Then, to detect the pressure p and temperature Tm of the pressure detector 11 and the temperature sensor 17 respectively control solenoid proportional pressure reducing valves 13a, 13b, 13c pilot oil on the downstream side of the detection pilot line T ₆ of.

A controller 12 shown in FIG. 2 is provided at an operation signal from the switches 10a and 10b, a pressure signal from the pressure detector 11, a temperature signal from the temperature sensor 17 and a bending portion of the working machine, and its rotation angle. α, β, γ
Angle sensors 16a, 16b, 16c for detecting
The input unit 12a receives an angle signal from the controller 11 and performs various calculations based on the operation signal, the pressure signal, the temperature signal, and the angle signal. A calculating unit 12b for determining whether or not the operation of the control electromagnetic proportional pressure reducing valves 13a to 13c is abnormal based on the operation delay time;
a to 13c and control signals for controlling the electromagnetic switching valve 1
And an output unit 12c for outputting a control signal or the like for controlling the control unit 4. The calculation unit 12b calculates the position coordinates of the tip of the working machine based on the angle signals representing the rotation angles α, β, and γ of each mechanism element of the working machine, and the coordinates are set in advance near the cab or the like. Also, when a part of the working machine enters the interference prevention area, a drive signal is output to open the electromagnetic proportional pressure reducing valve 13a, and the arm pulling operation is performed. By suppressing the operation,
It exerts a security function to retract the tip of the work equipment from the interference prevention area.

As described above, the auxiliary pilot oil supply line T
Electromagnetic proportional pressure-reducing valves 13a to 13c are interposed in the pilot pipes branched from ₂ respectively, and shuttle valves 8a, 8b, 8c provided on the downstream side thereof are respectively
The higher of the pilot oil flowing out of one of the electromagnetic proportional pressure reducing valve 13a and the operating lever device 1b, one of the electromagnetic proportional pressure reducing valve 13b and the operating pedal device 1d, and the pilot oil flowing out of the other of the electromagnetic proportional reducing valve 13c and the operating pedal device 1d. pilot lines T ₃ arm pushing pilot oil pressure receiving chamber 2b ₁ of the direction switching valve 2b via a right offset pilot line T ₄ and left offset pilot line T _5, one of the pressure in the offset direction switching valve 2d the chamber 2d ₁ and the other pressure chamber 2d ₂ and supplies preferentially.

Next, the operation of this embodiment will be described. For example, when the driver grips the grip portion of the operation lever device 1a (1c) with the right hand and appropriately operates in the front-rear direction, a pilot hydraulic pressure corresponding to the operation amount is transmitted from the boom control operation lever device 1a to the direction switching valve 2a. The direction switching valve 2a is switched on the basis of the applied pilot pressure, and the direction and amount of pressure oil supplied to the boom cylinder 3a are controlled. Similarly, when the operation lever device 1a (1c) is appropriately operated in the lateral direction, the pressure oil supplied from the direction switching valve 2c to the bucket cylinder 3c based on the pilot oil pressure output from the bucket control operation lever device 1c. The outflow direction and supply amount are controlled.

When driving the offset cylinder 3d, for example, the right switch 1
By pressing 0a, a right offset operation signal OFr from the switch 10a is input to the input unit 12a of the controller 12. Thereby, the output unit 12c
Since the ON signal is output to the solenoid proportional pressure reducing valve 13b for the right offset from the pilot oil is the solenoid proportional pressure reducing valve 13b from the secondary pilot oil supply line T _2, the shuttle valve 8b
And applied to the pressure receiving chamber 2d ₁ direction switching valve 2d via the right offset pilot line T _4. As a result, the spool of the direction switching valve 2d moves rightward in FIG.
The offset cylinder 3d is extended to perform a right offset operation.

Similarly, by pressing the left switch 10b with the left finger, a left offset operation signal OF1 from the switch 10b is input to the controller 12, and the controller 12 controls the left offset electromagnetic proportional pressure reducing valve 13c. opened, the pilot oil from the secondary pilot oil supply line T ₂ is applied to the pressure receiving chamber 2d ₂ direction switching valve 2d via the electromagnetic proportional pressure reducing valve 13c, the shuttle valve 8c and left offset pilot line T ₅ . As a result, since the spool of the direction switching valve 2d moves to the left in FIG. 1, the offset cylinder 3d is contracted and the left offset operation is performed.

The operation unit 12 of the controller 12
When the left and right offset operation signals OFl and OFr are input to the input unit 12a from the switches 10a and 10b, the output unit 12c outputs drive currents Ia and Ib from the output unit 12c to the left and right electromagnetic proportional pressure reducing valves 13a and 13b. When the offset operation signals OFl, OFr are cut off, the drive currents Ia, Ib output to the offset electromagnetic proportional pressure reducing valves 13a, 13b are immediately cut off, and the pressure detector 11 is turned off.
Monitoring the pilot oil pressure p downstream of the check valves 15a to 15c detected in the step (a), and after the drive currents Ia and Ib output to the offset electromagnetic proportional pressure reducing valves 13a and 13b become zero, An operation delay time Td until the hydraulic pressure p switches from high pressure to low pressure is calculated.

Incidentally, for example, the electromagnetic proportional pressure reducing valve 13b
In the case where the electromagnetic pressure reducing valve 13b becomes open due to biting of a foreign substance or the like, and the drive current Ib output to the electromagnetic proportional pressure reducing valve 13b becomes 0, the electromagnetic pressure reducing valve 13b is in an open state and no offset. Cylinder 3d runs away. If the calculated operation delay time Td exceeds the proper operation delay time Tn, the calculation unit 12b of the controller 12 determines that the operation of the electromagnetic proportional pressure reducing valve 13b is abnormal, and the output unit 12c sends the drive current to the electromagnetic switching valve 14. outputs is, the solenoid proportional pressure reducing valve to shut off by closing the solenoid switching valve 14 oil passage of the sub-pilot oil supply line T ₂ 13 a to 13 c
The supply of pilot oil to the plant. The above-described operation of determining whether the electromagnetic proportional pressure reducing valve 13b is operating abnormally is performed by the electromagnetic proportional pressure reducing valve 13b.
The same applies to a and the proportional pressure reducing valve 13c.

FIG. 3 shows the switches 10a, 10b, the pressure detector 11, the electromagnetic proportional pressure reducing valves 13b, 13c, and the electromagnetic switching when the electromagnetic proportional pressure reducing valves 13b, 13c operate normally and when they open due to a failure. It is a table | surface figure which shows the operation state of the valve 14 and the actuator. For example, when the switch 10a is pressed when the electromagnetic proportional pressure reducing valve 13b is normal, the drive current Ib is output from the output unit 12c to the electromagnetic proportional pressure reducing valve 13b, so that the electromagnetic proportional pressure reducing valve 13b is immediately activated and opened. pilot oil pressure is applied to the pressure receiving chamber 2d ₁ direction switching valve 2d via the right offset pilot line T _4, the spool of the direction switching valve 2d 1
And the offset cylinder 3d extends. Thereafter, when the switch 10a is pressed and released, the drive current Ib output to the electromagnetic proportional pressure reducing valve 13b becomes zero.
To become, from closing is pushed back to the spring valve body of the solenoid proportional pressure reducing valve 13b is not shown the flow path, the pilot oil is not supplied to the right offset pilot line T _4, spool neutral position of the directional control valve 2d And the offset cylinder 3d stops.

When the electromagnetic proportional pressure reducing valve 13b is open, the output unit 1
Since the valve body is strongly attracted by the electromagnetic force of the electromagnetic coil excited by the drive current Ib output from 2c, there is little possibility that the electromagnetic proportional pressure reducing valve 13b will be stuck. Therefore, in this specific example, when the electromagnetic proportional pressure reducing valve 13b is opened, the electromagnetic proportional pressure reducing valve 13 based on the pilot oil pressure p on the outflow side of the electromagnetic proportional pressure reducing valve 13b output from the pressure detector 11 is used.
The operation abnormality determination of b is not performed, and only the operation abnormality determination based on the operation delay time Td of the electromagnetic proportional pressure reducing valve 13b when the electromagnetic proportional pressure reducing valve 13b is closed is performed.

FIG. 4 shows a right offset operation signal OFr (a) when the switch 10a is pressed and then released.
Is a time course showing the solenoid proportional pressure reducing valve 13b of the driving current Ib (b) and a pressure detector 11 is a pilot hydraulic pressure p in detecting the pilot line T ₆ detected (c). FIG.
As shown in, the switch 10a at time t ₁ is press operation, when the release operation at time t _2, the solenoid proportional pressure reducing valve 13
The output waveform of the drive current Ib of b is the same as the right offset operation signal OFr, as shown in FIG. But,
The pilot oil pressure p in the detection pilot line T ₆ becomes zero when the drive current of the electromagnetic proportional pressure reducing valve 13b becomes zero at time t ₂ ,
It takes some time until the electromagnetic coil of the electromagnetic unit is demagnetized and the valve body is pushed back by the spring to close the flow path. Therefore, as shown in FIG.
Detecting a time t ₃ when dropped to _0, the time (t ₃ -t ₂₎
Is calculated as the operation delay time Td, and the operation abnormality of the electromagnetic proportional pressure reducing valve 13b is determined based on whether or not the operation delay time Td exceeds the proper operation delay time Tn.

The proper operation delay time Tn is the viscosity is a function of the temperature Tm of the pilot oil in the detection pilot line T _6, mainly detected pilot conduit T is the intrinsic value of the apparatus
Determined based on the piping resistance of ₆ . The pipe resistance of this device is measured in advance, and a correspondence table indicating the relationship between the pilot oil temperature Tm and the proper operation delay time Tn is stored in a memory (not shown) of the calculation unit 12b of the controller 12. The operation unit 12b reads the correspondence table from the memory, and obtains an appropriate operation delay time Tn corresponding to the temperature signal from the temperature sensor 17. When the electromagnetic proportional pressure-reducing valve 13b becomes hard, the operation delay time Td becomes abnormally long as shown by the broken line in FIG. When the controller 12 determines that the abnormal operation of the solenoid proportional pressure reducing valve 13b is a secondary pilot oil supply line T ₂ by outputting the drive current Is to close the electromagnetic selector valve 14 from is disconnection, the proportional solenoid valve 13b No pilot oil is supplied, and the direction switching valve 2d is automatically returned to the neutral position, so that the offset cylinder 3d stops. In addition, the operation of the other electromagnetic proportional valves 13a and 13c to determine the operation abnormality is exactly the same as the operation of the above-described electromagnetic proportional valve 13b to determine the operation abnormality.

As described above, in this specific example, the electromagnetic proportional valve 13
In the case where a to 13c break down in the operating state due to a foreign object biting or the like and cause trouble, runaway of the arm cylinder 3b and the offset cylinder 3d can be prevented, and the safety of the hydraulic shovel can be improved. When the offset cylinder 3d is operated, the operator can operate the hydraulic excavator simply by operating the switches 10a and 10b by hand instead of stepping on the operation pedal device 1d, so that the operator can easily operate the hydraulic excavator while maintaining a stable posture. Thus, operability when operating a work mechanism such as an offset is excellent.

In this specific example, the proportional solenoid valves 13a to 13a
Since to be interposed 13c to the sub-pilot line T ₂ branched from the main pilot oil feed line T _1, when any of the solenoid proportional valve 13a~13c has failed, together communicating their downstream since the pressure detector 11 provided in the pilot line T ₆ that outputs the detected high detection signal than normal to the controller 12 by the pilot pressure p, when the controller 12 determines that the abnormal operation electromagnetic switching valve 14
Is closed so that only the electromagnetic proportional valves 13a to 13c cannot be controlled. On the other hand, the operating lever device 1 a to 1 c, since it is possible to supply normally through 1e~1g and operating pedal device main pilot oil supply pipe T ₁ pilot oil supplied from the pilot pump 5 to 1d, hydraulic The switching operation of the direction switching valves 2a to 2g for controlling the direction and the flow rate of the hydraulic oil to the actuators 3a to 3g is performed by an electromagnetic switching valve 14.
Can be operated normally even if is closed.

[0026]

According to the claim 1, wherein as described above the invention according to the present invention, the drive current Tsu cross to close the control solenoid valve
Pilot pressure detected by the pressure detector from the time
Force measures the delay time until you drop below a predetermined value,
When the delay time has exceeded the proper operation time, it is determined that control solenoid valve is abnormally operation, since the output a drive current for you close the shutoff solenoid valve,
Even when the control solenoid valve is hard, the runaway of the hydraulic actuator can be prevented, and safety can be improved.

According to the second aspect of the present invention, the proper operation time changes in accordance with the temperature of the pilot oil, and the temperature detector provided in the pilot line or the hydraulic oil supply line to the actuator. Since the operation determination of the control solenoid valve is performed according to the value of the proper operation time corresponding to the temperature of the pilot oil detected by the above, more accurate operation determination can be performed according to the temperature of the pilot oil.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of an entire hydraulic excavator according to one embodiment of the present invention.

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

FIG. 3 is a diagram illustrating an operation state of a control device.

FIG. 4 is a time lapse diagram of a right offset operation signal OFr (a), a drive current Ib (b) of an electromagnetic proportional pressure reducing valve, and a pilot oil pressure p (c) in a detection pilot line.

[Explanation of symbols]

 1a to 1c, 1e to 1g Operating lever device 1d Operating pedal device 2a to 2g Direction switching valve 3a to 3g Hydraulic actuator 4 Main pump 5 Pilot pump 8a to 8c Shuttle valve 9 Control device 10a, 10b Switch 11 Pressure detector 12 Controller 13a -13c Electromagnetic proportional pressure reducing valve 14 Electromagnetic switching valve 15a-15c Check valve 16a-16c Angle sensor 17 Temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (72) Mitsuo Kihara Inventor, Tsuchiura Plant, Tsuchiura-shi, Ibaraki Pref. Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. (56) References JP-A-7-19207 (JP, A) JP-A-2 -108732 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02F 9/20-9/22 E02F 3/43 E02F 9/24 F15B 20/00

Claims (2)

(57) [Claims] 1. A plurality of direction switching valves for controlling the directions and flow rates of hydraulic oil supplied to a plurality of hydraulic actuators, respectively, and guiding pilot oil supplied from a pilot pump to pressure receiving chambers of the plurality of direction switching valves. A control device for a hydraulic construction work machine having at least one control solenoid valve interposed in a pilot pipe and operated in response to a drive current from the control device, wherein the control device is connected to a downstream side of the control solenoid valve. a pressure detector for detecting the pilot pressure in the pilot conduit which is, by a drive current from the previous SL controller provided a shut-off solenoid valve to cut off the supply of pilot oil to the control solenoid valve, said control apparatus wherein the pilot pressure is a predetermined value detected by said pressure detector from the time the drive current was Tsu cross to close the control solenoid valve
Measuring the delay time until you drop below, the determination when the delay time <br/> had exceeded the proper operation time, the control device shall the control solenoid valve is abnormally operating and, a hydraulic construction machine of the control device being characterized in that so as to output the driving current for you close the shut-off solenoid valve. 2. An operating oil supply line to be referred to when the control device determines the operation of the control solenoid valve changes according to the temperature of the pilot oil. 2. The hydraulic type according to claim 1, wherein the operation of the control solenoid valve is determined in accordance with a value of the appropriate operation time according to a temperature of the pilot oil detected by a temperature detector provided in the inside. Control device for construction work machines.