JPH09165788A - Control lever controlling circuit for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a travelling lever out of a position in front of an operator's seat, and improve the workability with front visibility improved. SOLUTION: A solenoid operated directional control valve 36 is installed at the middle of a first pilot hydraulic line 11 connected to a control lever 6 and a fifth pilot hydraulic line 38 is branched off out of its secondary side while a solenoid operated directional control valve 37 is installed at the middle of a second pilot hydraulic line 12 and a sixth pilot hydraulic line 39 is branched off out of its secondary side. The fifth and the sixth pilot hydraulic lines 38 and 39 are connected respectively to pilot ports 26 and 27 of a directional control valve 25. With a switch 35 of the control lever 6 turned on, switching is made at each of the solenoid operated directional control valves 36, 37, 40 and 41 and solenoid operated opening/shutting valves 42 and 43. With the control lever 5 operated in the forward and the rearward directions under such conditions, signal pressure guided out to the first and the second pilot hydraulic lines 11 and 12 is supplied either to the pilot port 26 or the pilot port 27 of the directional control valve 25 and switching is made at the directional control valve 25, making a travelling motor 28 turn for operation. Therefore, the travelling motor 28 can be controlled by operation of the control level 6, and thereby a conventional travelling lever can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control lever control circuit for a construction machine, and more particularly to a control lever control circuit for driving an actuator in response to forward / backward operation or left / right operation.

[0002]

2. Description of the Related Art FIG. 5 shows the interior of a cabin of a conventional hydraulic excavator. A driver's seat 2 is installed on a cabin floor plate 1, control stands 3 and 4 are installed upright on the left and right sides of the driver's seat 2, and control levers 5 and 6 are installed. To provide. The control levers 5 and 6 are swingable back and forth and left and right, respectively, and actuators such as a boom and a bucket are driven in response to operations in each direction.

Further, left and right traveling pedals 7, 8 are provided on the cabin floor plate 1 in front of the driver's seat 2 so as to be swingable back and forth, and traveling levers 9, 10 are fixed to the respective traveling pedals 7, 8. is there.

FIG. 6 shows a part of a control circuit of a conventional control lever. The right control lever 6 has first and second pilot oils that generate a signal pressure by operating the control lever 6 in the front-rear direction. Roads 11 and 12,
Third and fourth pilot oil passages 13 and 14 for generating a signal pressure by operating the control lever 3 in the left-right direction.
Are provided.

The first and second pilot oil passages 11,
12 is a pilot port 16 of the first directional control valve 15,
17, connected to the third and fourth pilot oil passages 13,
14 is a pilot port 19 of the second directional control valve 18,
Connected to 20. Further, the secondary pressure of the first directional control valve 15 controls the first actuator 21, and the secondary pressure of the second directional control valve 18 controls the second actuator 22.

For example, if the first actuator 21 is a boom cylinder and the second actuator 22 is a swing motor, when the control lever 3 is operated in the front-back direction, the first directional control valve 15 switches. When the boom cylinder expands and contracts and the control lever 3 is operated in the left-right direction, the second directional control valve 18 is switched and the swing motor is rotated in either the left-right direction.

The traveling pedal 8 which is integral with the right traveling lever 10 is provided with traveling pilot oil passages 23 and 24 which generate a signal pressure by operating the traveling lever 10 and the traveling pedal 8 in the front-rear direction. The traveling pilot oil passages 23 and 24 are connected to the pilot port 26 of the directional control valve 25,
27, and the traveling motor 28 on the right side is controlled by the secondary pressure of the directional control valve 25.

Therefore, the traveling pedal 8 is operated by the foot of the operator.
When the travel lever 10 is manually operated in the front-rear direction, the directional control valve 25 is switched to rotate the travel motor 28 and the right crawler (not shown) is operated in the front-rear direction. Be driven to.

Reference numeral 29 is a main pump, 30 is a relief valve, 31 is an oil pressure source, and 32 is a tank. The control circuit on the left control lever 5 side is also configured similarly to the control circuit on the right control lever 3 side shown in FIG.

[0010]

In conventional construction machines such as hydraulic excavators, since the left and right traveling levers are provided in front of the driver's seat, the front view is obstructed during general work such as excavation. Workability was poor.

Therefore, there is a technical problem to be solved in order to eliminate the traveling lever from the front position of the driver's seat and improve the front field of view, and the present invention aims to solve this problem. And

[0012]

SUMMARY OF THE INVENTION The present invention has been proposed in order to achieve the above-mentioned object. A control lever is swingably installed in a driver's seat, and a signal pressure is generated by operating the control lever back and forth. The first and second pilot oil passages, and the third and fourth pilot oil passages that generate the signal pressure by operating the control lever left and right are provided, and the first and second pilot oil passages are connected to the first pilot oil passage. The third and fourth pilot oil passages are connected to the pilot port of the second directional control valve while being connected to the pilot port of the directional control valve. In the construction machine in which the second actuator is controlled by the secondary pressure of the second directional control valve, the control lever is provided with a switch, and the first and second Electromagnetic switching valves that can be switched by the switches are provided in the pilot oil passages, respectively, and the fifth pilot oil passage is branched from the secondary side of one electromagnetic switching valve, and the secondary side of the other electromagnetic switching valve is provided. A control lever control circuit of the construction machine, which branches the sixth pilot oil passage and connects the fifth and sixth pilot oil passages to the pilot port of the directional control valve for the traveling motor, and the third and fourth When the electromagnetic switching valves which are switchable by the switches are provided in the pilot oil passages, and the electromagnetic switching valves are switched to the fifth and sixth pilot oil passage sides,
A control lever control circuit for a construction machine in which each electromagnetic on-off valve is switched to a closed position.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. For convenience of explanation, the same reference numerals are given to the same components as those in the related art, and the description is omitted.

FIG. 1 shows the interior of the cabin of the hydraulic excavator. Compared to the interior of the conventional cabin shown in FIG. 5, the cabin floor plate 1 in front of the driver's seat 2 has left and right traveling pedals 7,
No. 8 is provided so that it can swing back and forth, and no traveling lever is provided.

Further, as shown in FIG. 2, a switch 35 is provided on either one of the control levers 6, and the operator holds the control lever 6 while holding the switch 35.
5 is formed so that it can be turned on and off. The switch 3
When 5 is turned on, the directional control valve for the traveling motor is switched and the traveling motor is driven as described later.

FIG. 3 shows a part of the control circuit of the control lever. The right control lever 6 is provided with first to fourth pilot oil passages 11 to 14. An electromagnetic switching valve 36 is provided in the middle of the first pilot oil passage 11, and an electromagnetic switching valve 37 is provided in the middle of the second pilot oil passage 12.

Then, the fifth pilot oil passage 38 is branched from the secondary side of one electromagnetic switching valve 36, and the sixth pilot oil passage 3 is branched from the secondary side of the other electromagnetic switching valve 37.
9 is branched and the fifth and sixth pilot oil passages 38, 3 are
9 is connected to the pilot ports 26, 27 of the directional control valve 25 for the traction motor 28.

Further, an electromagnetic switching valve 40 is provided in the middle of the fifth pilot oil passage 38, and an electromagnetic switching valve 41 is provided in the middle of the sixth pilot oil passage 39. One solenoid switching valve 4
The pilot oil passage 23 on the forward side of the right traveling pedal 8 is connected to the primary side of 0, and the pilot oil passage on the reverse side of the right traveling pedal 8 is connected to the primary side of the other electromagnetic switching valve 41. 24 is connected.

An electromagnetic opening / closing valve 42 is provided in the middle of the third pilot oil passage 13, and an electromagnetic opening / closing valve 43 is provided in the middle of the fourth pilot oil passage 14. Now, when the switch 35 is off, no signal is sent from the controller 44 to the electromagnetic switching valves 36, 37, 40, 41, and the electromagnetic switching valves 36, 37, 40, 41 hold the positions shown in the figure. To do. Further, no signal is sent to the electromagnetic on-off valves 42 and 43, and the electromagnetic on-off valves 42 and 43 maintain the open position.

When the control lever 6 is operated in the front-back direction in this state, the first and second pilot oil passages 1
A signal pressure is supplied to the pilot port 16 or 17 of the first directional control valve 15 via 1 and 12 to drive the first actuator 21.

On the other hand, when the control lever 6 is operated in the left-right direction, the third and fourth pilot oil passages 1
A signal pressure is supplied to the pilot port 19 or 20 of the second directional control valve 18 via 3, 14 to drive the second actuator 22.

For example, if the first actuator 21 is a boom cylinder and the second actuator 22 is a swing motor, when the control lever 3 is operated in the front-back direction, the first directional control valve 15 switches. When the boom cylinder expands and contracts and the control lever 3 is operated in the left-right direction, the second directional control valve 18 is switched and the swing motor is rotated in either the left-right direction.

When the travel pedal 8 is stepped on in the front-rear direction, the signal pressure derived to the travel pilot oil passages 23, 24 is transmitted to the pilot port of the directional control valve 25 via the electromagnetic switching valves 40, 41. 26 or 27,
The direction control valve 25 is switched and the traveling motor 28 is rotated.

Therefore, by depressing the traveling pedal 8 while operating the control lever 3, it is possible to perform excavation, turning and the like work and the forward and backward movement of the machine body in parallel.

Here, when the switch 35 is turned on, the controller 44 causes the electromagnetic switching valves 36, 3 to be turned on.
7 and 40, 41, and electromagnetic switching valves 42, 43, signals are sent to the electromagnetic switching valves 36, 3 as shown in FIG.
7, 40, 41 is switched and the solenoid on-off valve 4
2, 43 switch to the closed position.

When the control lever 6 is operated in the front-rear direction in this state, the first and second pilot oil passages 1
The signal pressures derived to 1 and 12 are not supplied to the pilot ports 16 and 17 of the first directional control valve 15, and the electromagnetic switching valves 36 and 37 to the fifth and sixth pilot oil passages 38,
39, and is further supplied to the pilot port 26 or 27 of the directional control valve 25 via the electromagnetic switching valves 40 and 41. Therefore, the direction control valve 25 is switched and the traveling motor 28 is rotated.

On the other hand, when the control lever 6 is operated in the left-right direction, the third and fourth pilot oil passages 1
The signal pressures derived to 3, 14 are the electromagnetic on-off valves 42, 43.
Therefore, the second actuator 22 is not driven.

The switch 35 is set so as to be turned on only when the control lever 6 is in the neutral position. While the control lever 6 is driving the first or second actuator 21, 22, Each electromagnetic switching valve 36, 37, 40, 41, and electromagnetic opening / closing valve 42,
43 is switched to prevent the travel motor 28 from suddenly rotating.

Further, even if the travel pedal 8 is stepped on and off in the state where the switch 35 is turned on, the signal pressure derived to the travel pilot oil passages 23, 24 is transmitted from the electromagnetic switching valves 40, 41. Since it returns to the tank 32, the traveling pedal 8
It is possible to prevent erroneous operation.

When the control lever 6 is set to the neutral position and the switch 35 is turned off, the signals from the controller 44 to the electromagnetic switching valves 36, 37, 40, 41 and the electromagnetic switching valves 42, 43 are cut. , Electromagnetic switching valves 36, 37, 40, 41 and electromagnetic switching valves 42, 4
3 returns to the position shown in FIG.

Therefore, the control lever 6 returns to the normal state, the first actuator 21 is driven when the control lever 6 is operated in the front-rear direction, and the second actuator 21 is operated when the control lever 6 is operated in the left-right direction. The actuator 22 is driven. Further, when the travel pedal 8 is stepped on in the front-rear direction, the travel motor 28 rotates, and the excavation or turning operation and the forward / backward movement of the machine body can be performed again in parallel.

Although not shown, the control circuit on the left control lever 5 side has the same structure as the control circuit on the right control lever 3 side shown in FIG. By turning on the switch 35 provided in the above, each electromagnetic switching valve and electromagnetic switching valve on the left control lever 5 side are also switched at the same time.

Therefore, the present invention can be variously modified without departing from the spirit of the present invention, and it is obvious that the present invention extends to the modified one.

[0034]

As described above, in the present invention, the traveling motor is controlled by operating the control lever by switching the switch provided on the control lever without providing the traveling lever in front of the driver's seat. ing.
Therefore, the traveling lever can be eliminated from the front position of the driver's seat,
Good visibility in the front.

Thus, the field of view in the front is not obstructed during work such as excavation, which contributes to improvement in workability.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is an explanatory perspective view of the interior of a cabin of a hydraulic excavator.

FIG. 2 is a side view of a main part of one control lever.

FIG. 3 is a control circuit diagram of a control lever with a switch in an off state.

FIG. 4 is a control circuit diagram of the control lever with the switch turned on.

FIG. 5 is an explanatory perspective view of the inside of a cabin of a conventional hydraulic excavator.

FIG. 6 is a control circuit diagram of a conventional control lever.

[Explanation of symbols]

 2 Driver's seat 5,6 Control lever 11 First pilot oil passage 12 Second pilot oil passage 13 Third pilot oil passage 14 Fourth pilot oil passage 15 First directional control valve 16,17 Pilot port 18th 2 Directional control valve 19,20 Pilot port 21 First actuator 22 Second actuator 25 Directional control valve 26 (for traveling motor) 26,27 Pilot port 28 Traveling motor 35 Switch 36,37 Electromagnetic switching valve 38 Fifth pilot Oil passage 39 Sixth pilot oil passage 40,41 Electromagnetic switching valve 42,43 Electromagnetic on-off valve 44 Controller

Claims (2)

[Claims] 1. A first and a second pilot oil passages in which a control lever is swingably installed in a driver's seat and a signal pressure is generated by front and rear operation of the control lever, and a signal pressure by left and right operation of the control lever. And a third pilot oil passage for generating
Connected to the pilot port of the first directional control valve, the third and fourth pilot oil passages to the pilot port of the second directional control valve, and further to the first directional control valve. In the construction machine in which the first actuator is controlled by the secondary pressure of, and the second actuator is controlled by the secondary pressure of the second directional control valve, a switch is provided on the control lever, First and second
Each of the pilot oil passages is provided with an electromagnetic switching valve that can be switched by the switch, and the fifth pilot oil passage is branched from the secondary side of one electromagnetic switching valve and the secondary side of the other electromagnetic switching valve. From the 6th pilot oilway,
A control lever control circuit for a construction machine, wherein the fifth and sixth pilot oil passages are connected to a pilot port of a directional control valve for a traveling motor. 2. When the third and fourth pilot oil passages are provided with electromagnetic on-off valves which can be switched by the switches, respectively, and the electromagnetic switching valve is switched to the fifth and sixth pilot oil passage sides. The control lever control circuit for a construction machine according to claim 1, wherein each electromagnetic on-off valve is switched to a closed position.