JPH0867263A - Automatic straight advance resetting device in construction machine - Google Patents

Abstract

PURPOSE: To improve remote controllability by switching a resetting switching valve in order to supply pilot pressure oil, in a side of resetting a steering actuator to a straight advance condition, to a control valve. CONSTITUTION: In the case of performing remote steering, in a condition of switching a manual-remote changeover switch 15 to a remote side, when a stick lever S is operated, based on a control command from a receiving control part R, a remote switching valve 12 is switched to a right/left steering side position, to supply pilot pressure oil to pilot ports 6e, 6f of a control valve 6. In this way, the control valve 6 is switched to a right or left steering side position, to supply pressure oil to right/left hydraulic cylinders 3, 2, so as to perform steering to a right or left side. At right/left steering time by remote control thus operated, when the stick lever S is reset to a neutral position to stop outputting a valve switching signal, a machine body is automatically reset to a straight advancing condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic rectilinear return device for a construction machine having a remotely operated steering mechanism.

[0002]

BACKGROUND OF THE INVENTION Generally,
Some construction machines can be steered left and right by supplying pressure oil to a steering actuator such as a hydraulic cylinder. When working with such a construction machine, unmanned remote control may be performed, and at that time, left and right steering is also performed by remote control. Direction (turn)
Press the switch, left steering (turn) switch,
The steering stick lever switch is operated by tilting it to the left and right steering sides.

By the way, such a remote steering function is available only when the steering switch is operated. Therefore, in order to return the steering body to the straight traveling state, it is necessary to perform the steering operation. It is necessary to perform the reverse switch operation and stop the switch operation when the vehicle goes straight. However, since it is a remote operation, it is difficult to judge that the vehicle is in a straight traveling state, and it is difficult to judge when traveling far away. However, there is a problem that the operation of the switch on the opposite side is required to return the switch and the operation is troublesome and complicated, and the vehicle is forced to travel while meandering left and right.

[0004]

SUMMARY OF THE INVENTION The present invention was conceived with the object of providing an automatic rectilinear return device for a construction machine capable of eliminating these drawbacks in view of the above circumstances. A steering mechanism that operates by supplying pressure oil to the steering actuator accompanying the switching operation of the control valve, and a switching mechanism based on an operation command from a remote operation tool to supply pilot pressure oil for switching the control valve. In a construction machine equipped with a remote switching valve for switching, a switching valve for return that supplies pilot pressure oil for switching the control valve separately from the remote switching valve, and a steering mechanism for straight running, right steering, left Steering state detecting means for detecting which is the steering direction and whether pilot pressure oil is supplied from the remote switching valve Remote pilot pressure oil detection means for detecting, and a switching means for switching the return switching valve is connected to the steering state detection means and the remote pilot pressure oil detection means, and either one of right and left is connected. When steering is detected and pilot pressure oil supply from the remote switching valve is not detected, switch the return switching valve to supply pilot pressure oil on the side that returns the steering actuator to the straight traveling state to the control valve. It is characterized by having a configuration.

Further, according to the present invention, there is provided a steering mechanism which is operated by supplying pressure oil to a steering actuator in accordance with a switching operation of a control valve, and a remote operation for supplying pilot pressure oil for switching the control valve. In a construction machine provided with a remote switching valve that switches based on an operation command from a tool, steering state detection means for detecting whether the steering mechanism is straight ahead, right steering, or left steering. , Remote pilot pressure oil detecting means for detecting whether or not pilot pressure oil is supplied from the remote switching valve, and switching means for switching the remote switching valve, steering state detecting means and remote When connected to the pilot pressure oil detection means, either right or left steering is detected and pilot pressure oil supply from the remote switching valve is not detected Time, it also characterized by the fact that the configuration in which the switching of remote switching valve to supply pilot pressure oil on the side for returning the steering actuator running straight to the control valve.

Further, according to the present invention, a steering mechanism for steering operation by supplying pressure oil to a steering actuator and a steering mechanism for supplying pressure oil to the steering actuator are switched based on an operation command from a remote operation tool. In a construction machine equipped with a remote switching valve for switching, a switching valve for return that supplies pressure oil to the steering actuator separately from the remote switching valve, and a steering mechanism for straight driving, right steering, left steering In order to switch the return switching valve, there is provided a steering state detecting means for detecting which of the following is selected and a remote pressure oil detecting means for detecting whether or not pressure oil is supplied from the remote switching valve. The switching means of
By connecting to the steering state detecting means and the remote pressure oil detecting means,
When either right or left steering is detected and pressure oil supply from the remote switching valve is not detected, the return switching valve is switched to supply pressure oil on the side for returning to the straight-ahead state to the steering actuator. It is also characterized by being configured.

Still further, according to the present invention, there is provided a steering mechanism which is steered by supplying pressure oil to a steering actuator.
In a construction machine comprising a remote switching valve that switches based on an operation command from a remote operation tool to supply pressure oil to the steering actuator, the steering mechanism is straight, right-handed, or left-handed. Of the steering state detecting means for detecting whether or not pressure oil is being supplied from the remote switching valve, and remote pressure oil detecting means for detecting whether pressure oil is being supplied from the remote switching valve. The switching means is connected to the steering state detection means and the remote pressure oil detection means, and when either the right or left steering is detected and the pressure oil supply from the remote switching valve is not detected, the steering actuator It is also characterized in that the remote switching valve is switched to supply the pressure oil on the side for returning to the straight traveling state.

With this construction, the present invention automatically returns to the straight traveling state after left and right steering by remote control.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. In the drawing, reference numeral 1 denotes a vehicle body refraction type wheel-type tractor shovel, and the tractor shovel 1 includes left and right hydraulic cylinders 2 for connecting front and rear body frames 1a and 1b,
It is the same as in the past that the front and rear fuselage frames 1a and 1b are refracted around the turning pin 4 by retracting and retracting 3 in a contradictory manner, thereby steering (turning) to the right or left. However, in the tractor excavator 1 in which the present invention is implemented, the manual steering control in which the hydraulic cylinders 2 and 3 are expanded and contracted based on the steering wheel 5 being rotated by a driver who rides on the machine body. And two types of steering control, that is, remote steering control in which the hydraulic cylinders 2 and 3 are expanded and contracted based on an operation command from a remote operation tool (transmitter) C.

First, the hydraulic pressure supply to the hydraulic cylinders 2 and 3 by the manual steering control will be described with reference to the hydraulic circuit diagram shown in FIG. 2. Reference numeral 6 is a control valve, and the control valve 6 is a four-port three-port valve. The position switching valve has a first port 6a connected to an oil tank T and a second port 6b connected to a hydraulic pump P. The third port 6c is a contraction side port 2a of the left hydraulic cylinder 2 and an expansion side port 3b of the right hydraulic cylinder 3.
Further, the fourth port 6d is connected to the extension side port 2b of the left hydraulic cylinder 2 and the contraction side port 3a of the right hydraulic cylinder 3, respectively.

The control valve 6 is provided with the pilot pressure oil supplied to the left steering side pilot port 6e, from the hydraulic pump P to the reduction side port 2a of the left hydraulic cylinder 2 and the extension side of the right cylinder 3. It is set so as to be located at the left steering side position where the valve passage leading to the port 3b is opened. Also, right steering side pilot port 6
In the state where the pilot pressure oil is supplied to f, the valve passage extending from the hydraulic pump P to the contraction side port 3a of the right side hydraulic cylinder 3 and the extension side port 2b of the left side hydraulic cylinder 2 is located at the right steering side position. Further, in a state where the pilot pressure oil is not supplied to both pilot ports 6e and 6f, the first to fourth ports 6a to 6d are set to be in a neutral position where they are all closed.

On the other hand, 7 is a metering pump (orbit motor type) which is linked to the steering wheel 5.
And the left steering side port 7 of the metering pump 7
a is a left steering side pilot port 6e of the control valve 6 via first and second shuttle valves 8 and 9, which will be described later, and a right steering side port 7b is a third and fourth shuttle valve 10, Right steering side pilot port 6f via 11
Are connected to each. Then, the metering pump 7 measures the amount of pressure oil corresponding to the operation amount of the steering wheel 5 and supplies the pilot pressure oil to the pilot ports 6e and 6f, whereby the control valve 6 is operated to the left as described above. Pressure oil is supplied to the hydraulic cylinders 2 and 3 by switching to the facing position or the right steering position.

Next, the hydraulic pressure supply to the hydraulic cylinders 2 and 3 by the remote steering control will be described with reference to the hydraulic circuit diagram shown in FIG. 2 as well. 12 is turned off based on the operation command from the remote operation tool C. A remote switching valve for replacement, the remote switching valve 12 being a four-port three-position switching valve, the first port 12a of which is the oil tank T, the second port 12b of which is the hydraulic pump P, and the third port 12c.
Is connected to the first shuttle valve 8 and the fourth port 12d is connected to the third shuttle valve 10.

Here, the first and third shuttle valves 8, 10
Is the third and fourth ports 12 of the remote switching valve 12
First port 8a and 10a connected to c and 12d, and left steering side port 7 and right steering side port 7 of the metering pump 7.
Second ports 8b and 10b connected to a and 7b, and third ports 8c and 10c connected to pilot ports 6e and 6f of the control valve 6 via the second and fourth shuttle valves 9 and 11, respectively. Each has three ports. Then, the first and third shuttle valves 8, 10
In the valve bodies 8d and 10d of the above, the first ports 8a and 10a are closed by the bullets 8e and 10e and the second ports 8b and 1 are
0b and the third port 8c, 10c are always urged toward the open side of the valve passage, but when pilot pressure oil is supplied from the remote switching valve 12 as will be described later, the pilot pressure oil is not supplied. Pressure causes the valve bodies 8d and 10d to move against the bullets 8e and 10e, and the first ports 8a and 10e.
a valve passage that connects a to the third ports 8c and 10c opens,
Moreover, the second ports 8b and 10b are set to be closed.

As described above, the remote switching valve 12 switches based on the operation command from the remote operation tool C. In this case, the stick lever S for remote steering provided on the remote operation tool C is used. When it is tilted to the left steering side, a switching control signal of the remote switching valve 12 is output from the remote operation tool C, and the reception control unit R that receives this outputs the first switching signal from the hydraulic pump P to the remote switching valve 12. When the valve path to the shuttle valve 8 is opened to output so as to switch to the left steering side position for supplying pilot pressure oil to the left steering side pilot port 6e, and when the stick lever S is tilted to the right steering side. , Similarly, from the hydraulic pump P to the third shuttle valve 1
A switching command is output to open the valve path leading to 0 and switch to the right steering side position for supplying pilot pressure oil to the right steering side pilot port 6f. Then stick lever S
When the output of the switching command is stopped by returning the switch to the neutral position, the reception control unit R outputs a command to return the remote switching valve 12 to the neutral position in which all the ports 12a to 12d are closed. In this way, in addition to the manual steering control based on the manual operation of the steering wheel 5 described above, the remote steering control that supplies pilot pressure oil to the control valve 6 based on the operation command from the remote operation tool C is performed. It is configured to be able to. In the embodiment, the stick lever S is an automatic reset type that automatically returns to the neutral position when the operator lifts the hand up and down.

On the other hand, 13 is an electromagnetic return switching valve, which is a four-port three-position switching valve, the first port 13a of which is an oil tank T.
The second port 13b is connected to the hydraulic pump P, the third port 13c is connected to the second shuttle valve 9, and the fourth port 13d is connected to the fourth shuttle valve 11. Here, the second and fourth shuttle valves 9 and 11 are the third of the return switching valve 13, the pilot oil passage from the fourth ports 13c and 13d, or the first and third shuttle valves 8 and 10, respectively.
Select the high pressure side oil passage from the pilot oil passages from the
It is connected to f. The return switching valve 13 opens the valve passage from the hydraulic pump P to the second shuttle valve 9 when the left steering solenoid 13e is energized, and the pilot pressure is applied to the left steering pilot port 6e. In the left steering side position for supplying oil, and in the state where the right steering side solenoid 13f is energized, the valve passage from the hydraulic pump P to the fourth shuttle valve 11 is opened to open the right steering side pilot port. It is located on the right steering side position for supplying pilot pressure oil to 6f, and further includes both solenoids 13e, 13
In a state where power is not supplied to f, all ports 13a to
13d is set so as to be positioned in a neutral position to be closed, and in this way, the one based on the above-described turning operation of the steering wheel 5 and the one based on the operation command from the remote operation tool C are further separated. The pilot pressure oil can be supplied to the control valve 6 based on the switching operation of the return switching valve 13.

The left steering solenoid 13e of the return switching valve 13 has a right steering detection switch 14, which will be described later.
It is electrically connected to the battery 17 via the manual / remote changeover switch 15 and the right steering side pressure switch 16,
When all of these switches 14, 15 and 16 are closed, the left steering side solenoid 13e is energized. The right steering side solenoid 13f is electrically connected to the battery 17 via a left steering side detection switch 18, a manual-remote changeover switch 15, and a left steering side pressure switch 19, and these switches 18, 15, When all 19 are closed, the right steering side solenoid 13f is energized.

Here, the left steering side pressure switch 19 is connected to the oil passage A from the first shuttle valve 8 to the second shuttle valve 9, and the right steering side pressure switch 16 is connected to the third shuttle valve 10 to the first shuttle valve 10. Four oil passages B to the shuttle valve 11 are provided respectively, and these pressure switches 19 and 16
Is a meter-link pump 7 or a remote switching valve 1
When the pilot pressure oil is supplied from 2 and the pressure in the oil passages A and B becomes equal to or higher than the set pressure, it is set to switch from the closing side to the opening side.

Further, the manual / remote changeover switch 15
Is disposed in the driver's seat, and is set so that the switch contact is opened when the manual-remote selector switch 15 is switched to the manual side, and closed when switched to the remote side. Incidentally, the manual / remote changeover switch 15 may be provided on the side of the remote operation tool C, and the reception control section R may receive the manual / remote changeover command from the remote operation tool C to perform the corresponding changeover. Of course you can.

On the other hand, the turning pin 4 is integrally fixed to the front body frame 1a of the tractor shovel 1 and is rotatably supported by the rear body frame 1b. A pair of cam bodies 20 and 21 for right steering detection and left steering detection are integrally supported. These cam bodies 20 and 21 are disk-shaped, but the right steering detection cam body 20 has a large-diameter cam surface 20a formed on the right half of the outer peripheral edge portion, and the left steering detection is performed. Cam body 2
1, a large-diameter cam surface 21a is formed on the left half of the outer peripheral edge portion.

Further, the right steering detection switch 14,
The left steering detection switch 18 is arranged in the vicinity of the pivot pin support portion of the rear humm 1b, and the cam rollers 14b and 18b are provided at the tips of the switch levers 14a and 18a.
Is installed. In the left steering state, that is, in the state where the front body frame 1a is bent to the left with respect to the rear body frame 1b, the left steering detection cam body 2 is provided.
The cam surface 21a of No. 1 is brought into contact with the cam roller 18b attached to the left steering detection switch 18 to contact the switch lever 18
A is moved to the side where the push button 18c is pressed, whereby the switch contact of the left steering detection switch 18 is switched from the open side to the closed side. On the other hand, in the right steering state, that is, the front body frame 1a is the rear body frame 1
In the state of being bent to the right with respect to b, the cam surface 20a of the right steering detection cam body 20 has the right steering detection switch 14
The right steering detection switch 14 is switched from the opening side to the closing side. When the vehicle is in a straight traveling state, both cam bodies 20,
The cam surfaces 20a and 21a of 21 are cam rollers 14b and 18
Both switches 14 and 18 are open without touching b.

In the embodiment of the present invention constructed as described above, the manual steering control based on the turning operation of the steering wheel 5 and the remote steering control based on the operation of the stick lever S for remote steering are performed. Both steering controls can be performed. However, in the case of manual steering, if the steering wheel 5 is turned while the manual / remote selector switch 15 is switched to the manual side, the steering wheel 5 can be operated.
Based on the turning operation of the control valve 6, the metering pump 7 supplies pilot pressure oil corresponding to the operation amount to the pilot ports 6e and 6f of the control valve 6, whereby the control valve 6 moves to the left steering side position or the right side. By switching to the steering side position, pressure oil is supplied to the left and right hydraulic cylinders 2 and 3 to steer left or right.

On the other hand, in the case of remote steering, if the stick lever S is operated with the manual / remote selector switch 15 switched to the remote side, the control command from the reception control unit R is issued as described above. Based on this, the remote switching valve 12 is switched between the left steering side position and the right steering side position to supply pilot pressure oil to the pilot ports 6e, 6f of the control valve 6, whereby the control valve 6 is moved to the left steering side position. , Or by switching to the right steering side position and supplying pressure oil to the left and right hydraulic cylinders 2 and 3 to steer to the left or right. When the lever S is returned to the neutral position and the output of the valve switching signal is stopped, the machine body automatically returns to the straight traveling state.

That is, when the stick lever S is returned to the neutral position by releasing the hand from the stick lever S in the left steering state in which the stick lever S is tilted to the left steering side, for example, the remote switching valve 12 is moved to the left steering side. The position is switched from the neutral position to the neutral position. With the switching, the remote switching valve 12
Supply of pilot pressure oil to the left steering side pilot port 6e is stopped, whereby the pressure in the pilot oil passage A from the first shuttle valve 8 to the second shuttle 9 is reduced, and the left steering side pressure switch 19 Closes. On the other hand, at this time, since the machine body is in the left steering state, the left steering detection cam body 21 is in contact with the cam roller 18a, and the left steering detection switch 18 is closed. Further, as described above, the manual / remote changeover switch 15 is on the remote side, so that its switch contact is closed. Thus, all the switches 19, 15 and 18 provided in the power supply circuit from the battery 17 to the right steering solenoid 13f of the return switching valve 13 are closed, and the right steering solenoid is closed. 13f is energized, which causes the return switching valve 13 to switch to the right steering side position to supply pilot pressure oil to the right steering side pilot port 6f of the control valve 6, and further to supply the pilot pressure oil. Then, the control valve 6 is switched to the right steering side position to supply the pressure oil to the contraction side port 3a of the right side hydraulic cylinder 3 and the expansion side port 2b of the left side hydraulic cylinder 2.
The pressure oil is supplied to the hydraulic cylinders 2 and 3 when the airframe is in a straight-ahead state and the left steering detection switch 18 is opened, whereby the energization of the right steering solenoid 13f is cut off. The aircraft will stop, and the aircraft will automatically return to the straight traveling state.

On the other hand, when the remote steering stick lever S is tilted to the right steering side and then returned to the neutral position, the right steering side pressure switch 16 and the right steering detection switch 1
4. All the manual / remote changeover switches 15 are closed to energize the left steering side solenoid 13e, and based on this, pressure oil is applied to the reduction side port 2a of the left hydraulic cylinder 2 and the expansion side port 3b of the right hydraulic cylinder 2. Will be supplied, and the aircraft will automatically return to the straight-ahead state.

Incidentally, the automatic rectilinear return function described above is used when the manual-automatic changeover switch 15 is switched to the manual side, that is, when the manual steering is performed by the turning operation of the steering wheel 5. It does not operate because the switch contact of the automatic changeover switch 15 is open. Further, even when the stick lever S is operated to the left steering side and the right steering side, the pressure switches 19 and 1
Since 5 is open, the automatic rectilinear return function will not operate.

As described above, in the embodiment of the present invention, when the stick lever S for remote steering is used for left and right steering, if the stick lever S is returned to the neutral position, Will automatically return to the straight state. As a result, it is difficult to judge whether or not the vehicle is in the straight traveling state and it is difficult to turn, unlike the conventional one in which the stick lever S must be operated in the reverse direction in order to bring the machine body in the left-right steering state into the straight traveling state. I made it turn too much,
In order to correct this, the troublesome and complicated lever operation of repeatedly operating the stick lever S in the opposite direction is unnecessary, and the problem that the aircraft meanders left and right can be eliminated, and workability is improved. Is greatly improved.

Of course, the present invention is not limited to the above-mentioned first embodiment, and the shuttle valves 8, 9, 10, 11 in the first embodiment are the same as those in the second embodiment shown in FIG.
The pilot check valves 22, 23, 24 and 25 may be similarly configured. In the first and second embodiments, the control valve 6 is switched by supplying pilot pressure oil from the metering pump 7, the remote switching valve 12, or the return switching valve 13, and the switching operation of the control valve 6 is performed. The pressure oil is supplied to the hydraulic cylinder based on the so-called pilot system, but as in the third embodiment shown in FIG. 5, the metering pump 7, the remote switching valve 12, or the return switching valve 13 is used. Of course, the direct-acting type in which the pressure oil of (3) is directly supplied to the hydraulic cylinders 2 and 3 can be implemented. Further, the steering detecting means for detecting the steering means of the machine body is not limited to the one using the cam body and the cam roller as in the first embodiment, and various detecting means such as an angle detecting sensor are adopted. be able to. Further, needless to say, the present invention can be applied to various construction machines such as a wheel steering type tractor excavator instead of the vehicle body bending type tractor shovel.

By the way, in each of the above-mentioned embodiments, the machine body automatically returns to the straight traveling state after the remote steering operation. However, when there is a traveling work that does not require such an automatic straight traveling return function, As in the fourth embodiment shown in FIG.
An on / off switch 26 for connecting and disconnecting the power supply circuit to the solenoids 13e and 13f of the return switching valve 13
If the automatic straight line return function is required, the intermittent switch 26 is closed, and if the automatic straight line return function is not required, the intermittent switch 26 is opened. it can. Incidentally, the intermittent switch 26 is for arbitrarily selecting whether or not to activate the automatic rectilinear return function, and the manual-remote changeover switch 15 provided in the above-mentioned embodiment is automatically operated during manual steering. This is to prevent the rectilinear return function from operating.

Further, in the above-mentioned first to fourth embodiments, a dedicated return switching valve for returning straight ahead is provided separately from the remote switching valve for remote control. It is possible to automatically return to the straight traveling state by switching the remote switching valve without providing the valve. As an example of such a structure, FIGS. 7 to 10 show fifth to eighth embodiments.
Here, the description of the member devices having the same structures as those of the first to fourth embodiments is omitted and the same reference numerals are given.

First, the fifth embodiment shown in FIG. 7 will be described. The remote switching valve 27 used here has a structure substantially similar to that of the remote switching valve 12 of the first to fourth embodiments. The first port 27a is connected to the oil tank T, the second port 27b is connected to the hydraulic pump P, the third port 27c is connected to the first shuttle valve 8, and the fourth port 27d is connected to the third shuttle valve 10. However, the left steering side solenoid 27e is electrically connected to the battery 17 through the right steering detection switch 14, the manual-remote changeover switch 15, and the right steering side pressure switch 16 while being connected to the reception control unit R. It is connected to the. The right steering solenoid 27f is connected to the reception control unit R and
Left steering detection switch 18, manual-remote switch 1
5. It is electrically connected to the battery 17 via the left steering side pressure switch 19. Here, the left steering side pressure switch 19 is connected to the oil passage C from the third port 27c to the first shuttle valve 8, and the right steering side pressure switch 16 is connected to the oil passage C from the fourth port 27d to the third shuttle valve 10. The pressure switches 19 and 16 provided on the respective passages D are set so as to switch from the closing side to the opening side when the pressures in the oil passages C and D become equal to or higher than the set pressure.

In the fifth embodiment having the above-described structure, when the left and right steering stick lever S is returned to the neutral position after the left and right steering is performed by remote control, The solenoids 27f and 27e are energized, and based on this, the remote switching valve 27 is switched to a steering state opposite to that when the remote operation is performed, whereby the aircraft automatically returns to the straight traveling state. Become.
And in this thing, the remote switching valve 2 for remote control
Since 7 also functions as a return switching valve for returning straight, it is possible to use the switching valve in combination.
Dedicated return switching valve 1 used in the fourth embodiment
3, the oil passage from the metering pump 7 or the remote switching valve 12 and the return switching valve 13
Third and fourth shuttle valves 9 for switching the oil passage from
11 is also unnecessary, the number of parts can be reduced, and the structure can be simplified and the cost can be reduced.

Further, in the sixth embodiment shown in FIG. 8,
Instead of the first and third shuttle valves 8 and 10 in the fifth embodiment, either the metering pump 7 side or the remote switching valve 27 side high pressure side oil passage is selected and the pilot port 6e of the control valve 6 is selected. , 6f, and shuttle valves 28, 29 that are opened by pilot operation in order to flow the return oil from the opposite pilot ports 6f, 6e to the oil tank T side are used. Can be implemented while exhibiting the same effects as those of the fifth embodiment. Furthermore, in the seventh embodiment shown in FIG. 9, the metering pump 7 or the remote switching valve 27 is used as in the third embodiment.
10 is of a direct-acting type in which pressure oil is directly supplied to the hydraulic cylinders 2 and 3, while the eighth embodiment shown in FIG. Although provided, the same effects as those of the fifth embodiment can be obtained in the seventh and eighth embodiments.

[0034]

In summary, since the present invention is constructed as described above, pressure oil is supplied to the steering actuator in accordance with the switching operation of the remote switching valve based on the operation command from the remote operation tool. Steering operation will be performed, but in this case, the steering mechanism is in the right steering state or the left steering state, and the switching command from the remote operation tool is stopped and pressure oil is discharged from the remote switching valve. When not supplied, the valves are automatically switched to supply pressure oil to the side for returning the steering actuator to the straight-ahead driving state, whereby the machine body automatically returns to the straight-ahead driving state. As a result, in order to return the airframe in the steering state to the straight traveling state, the remote steering switch has to be operated in the reverse direction in order to switch the remote selector valve to the opposite side. It is difficult to judge whether or not to turn, and if you turn or not turn too much, you do not have to perform troublesome and complicated switch operation such as repeating to operate the remote control switch in the opposite direction to correct it. In addition, it is possible to eliminate the problem that the aircraft meanders left and right due to repeated switch operations in the opposite direction, and workability is greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a body refracting tractor shovel.

FIG. 2 is a hydraulic circuit diagram showing steering control in the first embodiment.

FIG. 3 is a view taken in the direction of arrow X in FIG.

FIG. 4 is a hydraulic circuit diagram showing steering control in the second embodiment.

FIG. 5 is a hydraulic circuit diagram showing steering control in a third embodiment.

FIG. 6 is a hydraulic circuit diagram showing steering control in a fourth embodiment.

FIG. 7 is a hydraulic circuit diagram showing steering control in a fifth embodiment.

FIG. 8 is a hydraulic circuit diagram showing steering control in a sixth embodiment.

FIG. 9 is a hydraulic circuit diagram showing steering control in a seventh embodiment.

FIG. 10 is a hydraulic circuit diagram showing steering control in an eighth embodiment.

[Explanation of symbols]

 2 Left side hydraulic cylinder 3 Right side hydraulic cylinder 5 Steering wheel 6 Control valve 7 Metering pump 8 First shuttle valve 10 Third shuttle valve 12 Remote changeover valve 13 Return changeover valve 14 Right steering detection switch 15 Manual-remote changeover switch 16 Right steering side pressure switch 18 Left steering side detection switch 19 Left steering side pressure switch 26 Intermittent switch 27 Remote switching valve C Remote operation tool

Front Page Continuation (72) Inventor Shigeru Hirabayashi 4-10-1 Yoga, Setagaya-ku, Tokyo New Caterpillar Mitsubishi Corp. (72) Inventor Akiaki, 4-10-1 Yoga, Setagaya-ku, Tokyo Shinki Within Mitsubishi Corporation

Claims (12)

[Claims] 1. A steering mechanism which is operated by supplying pressure oil to a steering actuator in accordance with a switching operation of a control valve, and an operation from a remote operation tool for supplying pilot pressure oil for switching the control valve. In a construction machine equipped with a remote switching valve that switches based on a command, a return switching valve that supplies pilot pressure oil for switching the control valve separately from the remote switching valve, and a steering mechanism goes straight, Steering right,
Steering state detection means for detecting which one of left steering,
Remote pilot pressure oil detection means for detecting whether pilot pressure oil is supplied from the remote switching valve, and switching means for switching the return switching valve, steering state detection means and remote Connected to the pilot pressure oil detection means, the pilot pressure on the side that returns the steering actuator to the straight running state when either the right or left steering is detected and the pilot pressure oil supply from the remote switching valve is not detected. An automatic rectilinear return device in a construction machine, characterized in that the return switching valve is switched to supply oil to a control valve. 2. A steering mechanism which is operated by supplying pressure oil to a steering actuator in accordance with a switching operation of a control valve, and an operation from a remote operation tool for supplying pilot pressure oil for switching the control valve. In a construction machine including a remote switching valve that switches based on a command, a steering state detecting unit that detects whether the steering mechanism is straight ahead, right steering, or left steering; and a remote switching valve. Remote pilot pressure oil detection means for detecting whether or not pilot pressure oil is being supplied from the remote control valve, and switching means for switching the remote switching valve, steering state detection means and remote pilot pressure oil detection. The steering device is connected to the steering means when either the right or left steering is detected and the pilot pressure oil supply from the remote switching valve is not detected. An automatic rectilinear return device for a construction machine, characterized in that a remote switching valve is switched to supply pilot pressure oil on the side for returning the steering actuator to a straight traveling state. 3. The supply of pilot pressure oil for switching the control valve according to claim 1 or 2, further supplied from a metering pump that supplies pilot pressure oil corresponding to an operation amount of a steering wheel that is manually operated. An automatic rectilinear return device for construction machinery, which is characterized in that 4. The supply of pilot pressure oil for switching a control valve according to claim 3, wherein the pilot pressure oil is supplied by remote control based on the operation of a remote operation tool and manually supplied by a metering pump based on manual operation. An automatic rectilinear return device for a construction machine, characterized in that switching means for switching is provided. 5. The connection circuit according to claim 1, 3 or 4, wherein the switching means for switching the return switching valve, the steering state detecting means, and the remote pilot pressure oil detecting means are connected to and disconnected from the circuit. An automatic rectilinear return device for a construction machine, which is provided with an intermittent switch means for. 6. The connection circuit according to claim 2, 3 or 4, wherein a switching means for switching the remote switching valve, a steering state detecting means and a remote pilot pressure oil detecting means are provided.
An automatic rectilinear return device for a construction machine, characterized by comprising an on / off switch means for connecting / disconnecting the circuit. 7. A steering mechanism that is operated to steer by supplying pressure oil to a steering actuator, and a remote switching valve that switches based on an operation command from a remote operation tool to supply pressure oil to the steering actuator. In a construction machine comprising: a return switching valve that supplies pressure oil to the steering actuator separately from a remote switching valve, and the steering mechanism is either straight ahead, right steering, or left steering. Steering state detection means for detecting whether or not pressure oil is being supplied from the remote switching valve, and remote pressure oil detection means for detecting whether or not pressure oil is being supplied from the remote switching valve, and switching means for switching the return switching valve is provided. When the steering state detecting means and the remote pressure oil detecting means are connected and either the right or left steering is detected and the pressure oil supply from the remote switching valve is not detected, An automatic rectilinear return device in a construction machine, characterized in that a switching valve for restoration is switched to supply pressure oil on the side for returning to a straight state to a steering actuator. 8. A steering mechanism for steering operation by supplying pressure oil to a steering actuator, and a remote switching valve for switching pressure oil to the steering actuator based on an operation command from a remote operation tool. In a construction machine provided with, the steering mechanism is straight ahead, right steering,
Steering state detection means for detecting which one of left steering,
Remote pressure oil detecting means for detecting whether or not pressure oil is supplied from the remote switching valve, and switching means for switching the remote switching valve, steering state detecting means and remote pressure oil detecting means. When the steering wheel is connected to the means and either the right or left steering is detected and the pressure oil supply from the remote switching valve is not detected, the steering actuator is remotely controlled to supply the pressure oil on the side for returning to the straight traveling state. An automatic rectilinear return device for a construction machine, which is configured to switch a switching valve. 9. The pressure oil supply to the steering actuator according to claim 7 or 8, further supplied from a metering pump that supplies pressure oil according to an operation amount of a steering wheel that is manually operated. An automatic rectilinear return device for construction machinery. 10. The supply of pressure oil to the steering actuator according to claim 9, is switched between remote control based on operation of a remote operation tool and manual control performed from a metering pump based on manual operation. An automatic rectilinear return device in a construction machine, characterized in that switching means is provided. 11. The method according to claim 7, 9, or 10,
A construction machine characterized in that a connecting circuit for connecting the switching means for switching the return switching valve, the steering state detecting means and the remote pressure oil detecting means is provided with an interrupting switch means for interrupting the circuit. Automatic rectilinear return device in. 12. The method according to claim 8, 9, or 10.
In a construction machine, a connection circuit for connecting the switching means for switching the remote switching valve, the steering state detecting means, and the remote pressure oil detecting means is provided with an interrupting switch means for disconnecting the circuit. Automatic straight return device.