JPH07197486A - Blade control device for construction machine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of the drag of a blade by a method wherein when running operation is effected in a case a working state where a blade is used is not produced, an elevation means is controlled so that the blade is raised to a non-ground touch position. CONSTITUTION:Turning ON and OFF of a lock switch 23 are decided by a microcomputer 21. When it is decided that the lock switch 23 is turn OFF, it is decided by the microcomputer 21 whether an OFF-signal is inputted from a running operation detector 24, namely, whether a running lever is operated. Further, when it is decided that the running lever is operated, the energization of a solenoid valve 13b is stopped by the microcomputer 21. A given amount of a current is made to flow through a solenoid valve 13a for a given time. By switching a spool 12c of a control valve 12, a cylinder 32 for driving a blade is shrunk and the blade is raised to a non-ground touch position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade control device used in a construction machine such as a hydraulic excavator having a blade, and more particularly to a blade control device for preventing undesired dragging of the blade.

[0002]

2. Description of the Related Art As a construction machine equipped with a blade (discharging plate) of this type, there is known one disclosed in, for example, Japanese Utility Model Publication No. 1-98256 and Japanese Utility Model Publication No. 1-98257. FIG. 9 shows a crawler type hydraulic excavator provided with a blade 31, and the blade 31 is moved up and down by extension of a hydraulic cylinder 32 as shown. When working using the blade 31 (blading work), the hydraulic cylinder 32 is used.
Is extended to ground the blade 31, and when the blade 31 is not used, the hydraulic cylinder 32 is contracted to float the blade 31 from the ground (non-grounded state).

[0003]

However, depending on the turning position of the hydraulic excavator, for example, the operator may use the blade 3
The condition of No. 1 cannot be visually observed, and therefore the blade 3
There is a problem that the blade 31 is often dragged while being grounded when the work is not used or when the construction machine is simply moved, which undesirably increases the load during running.

SUMMARY OF THE INVENTION An object of the present invention is to provide a blade control device for a construction machine in which the blade is not undesirably dragged during work without using the blade or when the construction machine is simply moved.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given with reference to FIG. 1 showing an embodiment, and the present invention will be described with reference to a blade 31 (FIG. 9).
A blade control device used in a construction machine, which includes an elevating means 32 for elevating the blade 31 between a grounded position and a non-grounded position, and an operating means 22 operated to operate the elevating means 32. Applied to. Then, a blading work detection unit 23 that detects whether or not the blade 31 is in a work state, a traveling operation detection unit 24 that detects whether or not a traveling operation of the vehicle is being performed, and a work that uses the blade 31 When it is detected that the running operation is performed while it is detected that the blade 31 is not in the state, the control means for controlling the elevating means 32 to raise the blade 31 to the non-grounded position regardless of the operation by the operation means 22. And 21 to solve the above problems. In particular, according to the second aspect of the present invention, when it is detected that the traveling operation is performed while it is detected that the blade 31 is not in the working state, the raising / lowering means 32 performs the raising operation of the blade for a predetermined time. It was done like this. The invention of claim 3 further comprises signal output means for outputting a predetermined height signal as the blade 31 is raised to a predetermined height, and when it is detected that the blade is not in a working state. When it is detected that the traveling operation has been performed, the ascending / descending means 32 raises the blade 31 until the predetermined height signal is output from the signal means. Further, the invention of claim 4 further comprises blade position detecting means 51, 21 for detecting whether or not the blade 31 is at a grounding position, and the traveling operation is performed when it is detected that the blade 31 is not in a working state. Even if it is detected that
When it is detected that the blade 31 is in the non-grounded position, the lifting operation of the blade 31 by the elevating means 32 is prohibited.

[0006]

When the traveling operation is detected while it is detected that the blade 31 is not in the working state, the blade 31 is automatically moved to the non-grounded position regardless of the operation of the operation means 22. Is raised up to.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

【Example】

-First Embodiment- A first embodiment of the present invention will be described with reference to Figs. FIG. 1 shows a blade control device for a construction machine according to the present invention. Discharge oil from the hydraulic pump indicated by reference numeral 11 is introduced to the above-mentioned blade driving cylinder 32 via a hydraulic pilot type control valve 12.

A pilot hydraulic pump 14 is connected to both pilot ports 12a and 12b of the control valve 12 via proportional solenoid valves (hereinafter simply referred to as solenoid valves) 13a and 13b, and the solenoid valves 13a and 13b are switched. The amount of pressure oil according to the amount acts on the pilot ports 12a and 12b. As a result, the spool 12c of the control valve 12 is switched by an amount corresponding to the pressure acting on the pilot ports 12a, 12b, and the amount of pressure oil (the discharge oil of the hydraulic pump 11) according to the switching amount is guided to the cylinder 32. . Further, when the solenoid valves 13a, 13b are switched to the neutral position shown in the figure, the pilot ports 12a, 1
2b is communicated with the tank, and the control valve 12 maintains the neutral position.

The pair of solenoid valves 13a and 13b are independently switched and controlled by a microcomputer (hereinafter, microcomputer) 21. An up / down switch 22, a lock switch 23, and a traveling operation detector 24 are connected to the microcomputer 21. The up / down switch 22 is composed of, for example, a slide type switch that can perform an up operation for raising the blade 31 and a down operation for lowering the blade 31, respectively, and an electric signal corresponding to each operation amount is output. It is input to the microcomputer 21. The lock switch 23 is a switch that is turned on when performing a braiding operation using the blade 31.

Further, the traveling operation detector 24 comprises, as shown in FIG. 2, for example, an electrical contact 43 provided on the rotating pin 42 of the traveling lever 41 and an electrical contact 44 provided on the traveling lever 41 side. When the traveling lever 41 is in the neutral position, both contacts 43 and 44 contact each other and an ON signal is input to the microcomputer 21. On the other hand, when the traveling lever 41 is operated to some extent (the amount at which the vehicle starts traveling), the contact between the contacts 43 and 44 is cut off and an off signal is input to the microcomputer 22, and the microcomputer 21 inputs this off signal. It is determined that the driving operation has been performed.

Next, the procedure of blade control by the microcomputer 21 will be described with reference to the flowchart of FIG. In FIG. 3, first, in step S1, the lock switch 23 is turned on.
Determine off. If it is on, the process proceeds to step S2, and it is determined whether or not the up / down switch 22 is performing an up operation. If the up operation has not been performed, the solenoid valve 13a is de-energized in step S3 to allow the pilot port 12a of the control valve 12 to communicate with the tank. After that, in step S6, it is determined whether or not the down operation is performed by the up / down switch 22, and if the down operation is not performed, the solenoid valve 13b is deenergized in step S7 and the pilot port 12b of the control valve 12 is connected to the tank. . That is, when neither the up operation nor the down operation of the up / down switch 22 is performed, the control valve 12 holds the neutral position, the cylinder 32 is not driven, and the blade 31 is not moved up and down.

When it is determined in step S2 that the up operation has been performed, the solenoid valve 13b is de-energized in step S4, and a current corresponding to the up operation amount is supplied to the solenoid valve 13a in step S5. As a result, an amount of the oil discharged from the pilot hydraulic pump 14 that corresponds to the switching amount of the solenoid valve 13a is guided to the pilot port 12a, and the spool 12c of the control valve 12 switches to the position on the left side in the figure according to the amount of oil. . Therefore, the hydraulic pump 1
The discharge oil of No. 1 is guided to the rod chamber of the cylinder 32 by an amount corresponding to the switching amount of the control valve 12,
Contract and the blade 31 rises. The ascending speed depends on the up operation amount of the up / down switch 22.

When it is determined in step S6 that the down operation has been performed, the solenoid valve 13a is de-energized in step S8, and a current corresponding to the down operation amount is supplied to the solenoid valve 13b in step S9. As a result, the solenoid valve 13
The amount of pressure oil according to the switching amount of b is the pilot port 12b.
The spool 12c of the control valve 12 is switched to the position on the right side in the figure according to the amount of oil. Therefore, the oil discharged from the hydraulic pump 11 is transferred to the control valve 12
Is guided to the bottom chamber of the cylinder 32 by an amount corresponding to the switching amount of, and the cylinder 32 extends to lower the blade 31. The descending speed depends on the amount of down operation of the up / down switch 22.

On the other hand, in step S1, the lock switch 23
Is determined to be off, it is determined in step S10 whether an off signal is input from the traveling operation detector 24, that is, whether the traveling lever 41 is operated.
When step S10 is denied, the solenoids 13a and 13b are de-energized and the cylinder 32 is stopped in step S11. If step S10 is positive, step S12
Then, the solenoid valve 13b is de-energized and a predetermined amount of current is passed through the solenoid valve 13a for a predetermined time. As a result, the spool 12c of the control valve 12 is switched to the position on the left side in the drawing, the cylinder 32 contracts, and the blade 31 moves up by a predetermined amount. Therefore, the blade 31
If is grounded, it will be ungrounded.

According to the above procedure, the lock switch 23
When the off signal is input from the traveling operation detector 24 while the power is off, that is, when it is detected that the blade 31 is not in the working state, it is detected that the traveling lever 41 is operated. Then, the blade 31 is automatically raised to the non-grounded position. Therefore,
Unnecessary dragging of the blade 31 can be prevented without particularly performing the up operation of the up / down switch 22 when the vehicle is traveling other than during the braiding work. In particular, in this embodiment, when the lock switch 23 is off, the operation of the up / down switch 22 is invalid and the lifting / lowering of the blade 31 is prohibited.
Can be prevented from rising and falling.

In the configuration of the above embodiment, the cylinder 3
The up / down switch 22 constitutes an operating means, the lock switch 23 constitutes a blading work detecting means, the traveling operation detector 24 constitutes a traveling operation detecting means, and the microcomputer 21 constitutes a controlling means.

In the above, when the operation of the traveling lever 41 is detected when the lock switch 23 is turned off, step S
Although the blade 31 is lifted for a predetermined time at 12, the blade 31 may be lifted until it reaches a predetermined height position. In this case, for example, a limit switch that is mechanically turned on when the blade 31 moves up to the predetermined height is provided, step S12 in FIG. 3 is changed to step S12 ′ in FIG. 4, and step S21 is added. do it. That is, step S1
At 2 ', the solenoid valve 13b is de-energized, and a predetermined amount of current is passed through the solenoid valve 13a to contract the cylinder 32. If the limit switch is off at step S21, the process returns to step S1 and is turned on. Then step S1
Go to 1.

-Second Embodiment- Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows the configuration of the blade control device in this embodiment, which is the same as FIG. 1 except that a ground position detection device 51 is provided. The ground position detecting device 51 is shown in FIG.
As shown in FIG. 7, it is composed of an angle sensor that detects the angle θ of the blade arm 31a from the horizontal position, and outputs a current signal I corresponding to θ as shown in FIG. Where θ
Is a predetermined angle θ'when the blade 31 is in contact with the ground.
(<0), and when the blade 31 moves up from this position, θ> θ '. Therefore, by comparing the signal I with a predetermined value I ′ (value when θ = θ ′), it is possible to determine in the microcomputer 21 whether or not the blade 31 is grounded.

FIG. 8 shows the control procedure in this embodiment.
Step S31 is added before step S10 in FIG. In step S31, it is determined whether or not the output I of the ground position detecting device 51 is equal to I ′, that is, whether or not the blade 31 is in contact with the ground. If affirmative, the process proceeds to step S10, and if negative, a step is performed. Proceed to S11. That is, in the present embodiment, even when it is detected that the traveling lever 41 is operated while it is detected that the blade 31 is not in the working state, if the blade 31 is already in the non-grounded position, the blade 31 Is not performed.

The ground height detecting device 51 is not limited to the above angle sensor, but may be a sensor for detecting the stroke amount of the cylinder 32, for example. Further, in the above-described embodiments, a device that detects whether or not the traveling lever 41 is operated is used as the traveling state detector 24.
A unit (for example, a potentiometer) that detects the manipulated variable itself of 1 may be used. Alternatively, the traveling lever 41
In the type in which the traveling control valve is switched via the traveling hydraulic pilot circuit in accordance with the operation of, the pressure switch that turns on when the pressure in the pilot circuit (depending on the operation amount of the traveling lever) becomes a predetermined value or more is provided. Alternatively, it may be determined that the traveling operation is performed by turning on the pressure switch. In this case, since there is a time lag between the pressure increase in the pilot circuit and the switching of the traveling control valve, the blade can be raised before the vehicle starts traveling. Further, the operating means is not limited to the up / down switch described above, and may be a lever or the like that mechanically switches the control valve 12. Further, the present invention can be applied to blade control devices used for construction machines other than hydraulic excavators.

[0022]

According to the present invention, when the traveling operation is performed while it is detected that the blade is not in the working state, the blade is automatically placed in the non-grounded position regardless of the operation of the operating means. Even if the operator cannot see the state of the blade due to the turning position of the construction machine, for example, when the work not using the blade or when the construction machine is simply moved, the blade is grounded while traveling. It is possible to prevent an undesired increase in the load during traveling. Especially when the blade is already in the non-grounded position, if the raising operation of the blade is prohibited, useless operation will not be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a blade control device for a construction machine according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a traveling operation detector.

FIG. 3 is a flowchart illustrating the operation of the first embodiment.

FIG. 4 is a flowchart showing a modified example of FIG.

FIG. 5 is a configuration diagram showing a blade control device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a detection angle of an angle sensor.

FIG. 7 is an output characteristic diagram of the angle sensor.

FIG. 8 is a flowchart illustrating the operation of the second embodiment.

FIG. 9 is a schematic side view of a hydraulic excavator including blades.

[Explanation of symbols]

 11 Hydraulic Pump 12 Control Valves 13a, 13b Solenoid Valve 21 Microcomputer 22 Up / Down Switch 23 Lock Switch 24 Traveling Operation Detector 31 Blade 32 Blade Driving Cylinder 51 Pair Value Height Detector

Claims (4)

[Claims] 1. A blade used in a construction machine comprising: a blade; an elevating means for elevating the blade between a grounded position and a non-grounded position; and an operating means operated to operate the elevating means. In the control device, a blading work detection means for detecting whether or not the blade is in a work state, a traveling operation detection means for detecting whether or not a traveling operation of the vehicle is performed, and a work using the blade When it is detected that the traveling operation is performed while it is detected that the state is not in the state, control for controlling the elevating means to raise the blade to the non-grounded position regardless of the operation by the operating means. And a blade control device for a construction machine. 2. The control means determines a raising operation of the blade by the elevating means when it is detected that the traveling operation is performed when it is detected that the blade is not in a working state. The blade control device for a construction machine according to claim 1, wherein the blade control device is performed only for a time. 3. The apparatus further comprises signal output means for outputting a predetermined height signal as the blade is raised to a predetermined height, and the control means detects that the blade is not in a working state. 2. When the running operation is detected during the above-mentioned operation, the raising operation of the blade by the elevating means is performed until the predetermined height signal is output from the signal means. A blade control device for a construction machine according to 1. 4. A blade position detecting means for detecting whether or not the blade is in a grounding position, wherein the control means carries out the traveling operation when it is detected that the blade is not in a working state. Even if it is detected that the blade is moved, if the blade is detected to be in the non-grounded position, the raising operation of the blade by the elevating means is prohibited.
A blade control device for a construction machine according to 1.