JPH0782767A - Trailer loading mode changeover device in construction machine - Google Patents

Abstract

PURPOSE:To simplify operation, by providing a trailer loading-mode position on a working mode changeover switch and retaining the engine at a middle speed in this mode so as not to exert effects on the traveling even when other actuators are driven. CONSTITUTION:When a working mode changeover switch 52 is switched over to a trailer loading-mode position TR, an independent position changeover instruction signal is output from a controller 53 to a traveling independent valve 9 and a middle rotary speed-retention instruction signal is output to the governer 22 of engine 21 through a stepping motor 33. At this time, the revolution of engine 21 can be retained at a middle speed regardless of the operational position of a throttle lever 35 and an autoaccelerating switch 38 and even if any other hydraulic actuators than traveling motors 1L, 1R are driven, the traveling is not affected. In this way, the switching operation can be carried out accurately with one touch without misoperation and hence, safety can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit equipped on a construction machine such as a hydraulic excavator, an engine, etc., and a switching device for setting a work mode corresponding to a work.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram of a main part of a prior art mounted on a hydraulic excavator (not shown). In the figure, 1L and 1R are left and right traveling motors of various hydraulic actuators, 2 is one hydraulic cylinder of a working hydraulic actuator, 3 is a swing motor, 4L and 4R are traveling switching valves, 5, 6 and 5, respectively. Reference numeral 7 is a pilot switching valve for controlling various hydraulic actuators, 8 is a pilot switching valve for turning, 9 is a traveling independent valve, reference numeral a is a traveling independent position of the traveling independent valve 9, reference numeral b is a traveling straight position, and 10 is an electromagnetic switching valve. , 11, 12 are pilot on-off valves, 13, 1 respectively
4 is the first and second pumps, 15 is the pilot pump, 20
Is an oil tank, 21 is an engine, 22 is a governor of the engine 21, 28 is an operation detecting means for detecting the operation / non-operation of an operation lever (not shown) for operating various hydraulic actuators, and 30 and 31 are electric respectively. Oil converter,
Reference numeral 32 is a controller, 33 is a stepping motor which is a control motor, 34 is a throttle device, 35 is a throttle lever, 36 is a potentiometer provided in the throttle device 34, 37 is a work mode switch, and 38 is an auto accelerator switch.

In the circuit of the prior art shown in FIG. 2, various hydraulic actuators mounted on the hydraulic excavator are divided into two groups A and B, and the left and right traveling switching valves 4L and 4R are arranged on the most upstream side of the groups A and B. Are arranged in tandem, and the other switching valves on the downstream side are arranged in parallel so that the hydraulic actuator can be operated by the first pump 13 and the second pump 14 via the respective switching valves. A traveling independent valve 9 is arranged in the discharge side oil passages of the pump 13 and the second pump 14. Therefore, when the hydraulic excavator is working, if it is desired to prevent the hydraulic actuators other than the traveling motors (4L, 4R) from being actuated or deactuated during traveling,
The traveling independent switch 39 is turned on. Solenoid 4
Since 0 is energized, the electromagnetic switching valve 10 is switched from the tank communication oil passage position a to the opening oil passage position b. The pilot pressure from the pilot pump 15 acts on the pilot pressure receiving portion 43 through the pipe 41, the position of the electromagnetic switching valve 10, and the pipe 42. Therefore, the traveling independent valve 9 is switched to the traveling independent position a. Therefore, the pressure oil from the second pump 14 passes through the pipeline 44, and one passes through the pipeline 45, and the traveling switching valve 4L.
On the other hand, the other is branched by the pipeline 44, and is supplied to the traveling switching valve 4R via the pipeline 46, the position a of the travel independent valve 9, and the pipeline 47. Further, the pressure oil from the first pump 13 is supplied to the pilot switching valve of the working hydraulic actuator through the pipe line 48, the position a of the traveling independent valve 9, the pipe line 49, and the check valves 50 and 51.

Further, the throttle lever 35 of the throttle device 34 is operated in the high idle operation direction (arrow Hi shown in FIG. 2).
Direction) or low idle operation direction (direction of arrow Lo)
When the adjustment operation is performed, the signal from the potentiometer 36 is input to the controller 32. The controller 32 makes a judgment based on the signal, and outputs a command signal to the governor 22 via the stepping motor 33. Thereby, the rotation of the engine 21 can be set to high speed or low speed. Also, by selectively switching the work mode changeover switch 37 according to the work content of the hydraulic excavator,
The engine (21) rotation can be set via the controller 32. That is, when the work mode changeover switch 37 is switched to the H mode, the engine 21 can be set to the maximum rotation speed (rated rotation speed), so that the maximum engine horsepower (rated horsepower) is input to perform heavy excavation or the like. be able to. Further, when the mode is switched to the S mode, the engine speed can be set to the medium speed, so that economical standard (excavation) work that achieves both work amount and fuel consumption can be performed with low noise. Further, when the mode is switched to the FC mode, it is possible to perform a light load precision work by setting the rotation speed to a very low speed. When the auto accelerator switch 38 is turned on and the operation levers of the various hydraulic actuators are all returned to the non-operating position (neutral position) while the throttle lever 35 is in the high idle position, the operation state is detected. Each signal from the device 28 is input to the controller 32. The controller 32 makes a determination based on the above signal and outputs a low idle rotation command signal to the governor 22 after a predetermined delay time. Therefore, the rotation of the engine 21 can be decelerated to save fuel consumption and reduce noise.

[0005]

When the hydraulic excavator is loaded onto the trailer by itself (including loading and unloading), the work attachment of the hydraulic excavator is moved to adjust the balance, and the climbing tool and the trailer loading platform are adjusted. You have to drive slowly over it. If the auto accelerator switch is set to the ON position when performing this work, if at least one operating lever is moved when all the operating levers are not operated and the engine is rotating at low idle, The rotation may rise suddenly and the hydraulic actuator may start moving rapidly. Therefore, always set the auto accelerator switch to the off position. Further, when the hydraulic actuator other than the traveling motor is operated, the traveling independent switch is always turned on so that the influence thereof does not affect traveling. Also, since you have to slowly run on the climbing equipment and the loading platform,
The work mode selector switch is switched to the S mode position to set the engine speed to medium speed. Therefore, when loading the trailer of the hydraulic excavator, it was necessary to perform all of the above-mentioned multiple switch operations with certainty.Therefore, the driver was nervous and anxious about whether the switch operations were correct. It was It is an object of the present invention to provide a trailer loading mode switching device that can solve the above problems.

[0006]

In the trailer loading mode switching device of the present invention, the various actuators mounted on the construction machine are divided into two groups A and B, and the left and right traveling switching valves are each group A and B. Placed in tandem on the most upstream side of
Further, the other switching valves on the downstream side are arranged in parallel so that the hydraulic actuators can be operated by the first and second pumps via the respective switching valves, and the discharge side oil passages of the first and second pumps can be connected. , The pressure oils from the first and second pumps are separately passed, the pressure oil from one of the pumps is supplied to the left and right traveling motors, and the pressure oil from the other pump is supplied to another working hydraulic actuator. It is equipped with a traveling independent valve that enables it, and also has a throttle device that sets the engine speed to high speed and low speed, so that the signal from the throttle device is input to the controller, and the operation detection of the hydraulic actuator operation lever is detected. Means for adjusting the engine speed to a predetermined idle speed via the controller when all the operating levers are in the non-operating position, and The engine rotation in response to the work content,
In a construction machine equipped with a work mode changeover switch that can be switched between high speed, medium speed, and fine speed via a controller, a trailer load mode position change signal is provided at the change position of the work mode change switch. Is input to the controller and the controller determines based on the trailer loading mode position switching signal, the controller outputs an independent position switching command signal to the traveling independent valve, and the controller sends the engine governor to the governor. On the other hand, the medium speed rotation maintaining command signal is output via the stepping motor.

[0007]

When the trailer is loaded by the self-propelled hydraulic excavator, the operation mode changeover switch is switched to the trailer loading mode position as a switch operation. When the trailer loading mode position switching signal is input to the controller, the controller judges based on that signal and outputs an independent position switching command signal from the controller to the electromagnetic switching valve provided in the pilot circuit of the traveling independent valve. At the same time, the controller outputs a medium speed rotation maintaining command signal to the stepping motor. Since the electromagnetic switching valve is switched to the open oil passage position and the pilot pressure acts on the pilot pressure receiving portion of the travel independent valve, the travel independent valve is switched to the travel independent position. At the same time, the stepping motor rotates to adjust the governor, so that the engine maintains the medium speed rotation. That is, when the work mode selector switch is switched to the trailer loading mode position, the engine rotation can be maintained at a medium speed regardless of the operating positions of the throttle lever and the auto accelerator switch, and any hydraulic actuator other than the traveling motor can be operated. Does not affect running.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of a main part of a hydraulic excavator including a trailer loading mode switching device of the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art. 52 is a work mode switch, 53
Is a controller, 10 'is an electromagnetic switching valve, and 40' is a solenoid of the electromagnetic switching valve 10 '. Next, the configuration of the trailer loading mode switching device of the present invention will be described with reference to FIG. In the present invention, the trailer loading mode position TR is provided at the switching position of the work mode switching switch 52, and when the work mode switching switch 52 is switched to the TR position, the trailer loading mode position switching signal is input to the controller 53. , The controller 53 makes a judgment based on the trailer loading mode position switching signal to output an independent position switching command signal from the controller 53 to the traveling independent valve 9 and also the controller 53 to the engine 21.
The medium speed rotation maintaining command signal is output to the governor 22 via the stepping motor 33.

Next, the operation of the trailer loading mode switching device of the present invention will be described. When you want to load the trailer by self-propelled hydraulic excavator, as a switch operation,
The work mode changeover switch 52 is changed over to the trailer loading mode position TR. When the trailer loading mode position switching signal is input to the controller 53, the controller 53 makes a determination based on the signal and outputs an independent position switching command signal from the controller 53 to the solenoid 40 'of the electromagnetic switching valve 10'. . Since the solenoid 40 'is energized, the electromagnetic switching valve 10' is switched from the tank communication oil passage position a'to the opening oil passage position b '. Pilot pressure from the pilot pump 15 acts on the pilot pressure receiving portion 43 through the pipe line 41, the low position of the electromagnetic switching valve 10 ′, and the pipe line 42. Therefore, the traveling independent valve 9 is switched to the traveling independent position a. At the same time, the controller 53 outputs a medium speed rotation maintaining command signal to the stepping motor 33.
Since the stepping motor 33 rotates to adjust the governor 22, the engine 21 maintains the medium speed rotation. That is, when the work mode selector switch 52 is switched to the trailer loading mode position TR, the engine (21) rotation can be maintained at a predetermined medium speed regardless of the operating positions of the throttle lever 35 and the auto accelerator switch 38, and the traveling motor ( Actuation of any hydraulic actuator other than 1L and 1R does not affect traveling.

[0010]

When the trailer is loaded by the hydraulic excavator by self-propelled, in the prior art, the switch operation is performed by setting the auto accelerator switch to the off position, the work mode changeover switch to the S mode position, and the independent running switch. Was being turned on. The driver was nervous about the operation of the plurality of switches, and I was worried whether or not there was an error in the operation of the switches. However, in the present invention, as the switch operation before loading the trailer, it is sufficient to switch the work mode changeover switch to the trailer loading mode position. By the trailer loading mode position switching operation, the traveling independent valve is switched to the traveling independent position, and the engine can maintain the middle speed rotation. In other words, if the trailer loading mode position switching operation is performed, the engine rotation can be maintained at a medium speed regardless of the operating positions of the throttle lever and the auto accelerator switch, and running of any hydraulic actuator other than the running motor will affect running. Will not be affected. Therefore, in the hydraulic excavator provided with the trailer loading mode switching device of the present invention, the switch operation before the trailer loading operation can be accurately performed with one touch, so that the switch operability and safety can be improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a main part of a hydraulic excavator including a trailer loading mode switching device of the present invention.

FIG. 2 is a circuit diagram of a main part of a conventional technique installed in a hydraulic excavator.

[Explanation of symbols]

 1L, 1R Travel motor 2 Hydraulic cylinder 3 Swing motor 9 Travel independent valve 10, 10 'Electromagnetic switching valve 13, 14 1st, 2nd pump 15 Pilot pump 21 Engine 22 Governor 28 Operation detection means 32, 53 Controller 33 Stepping motor 34 Throttle device 37,52 Working mode selector switch 38 Auto accelerator switch

Claims (1)

[Claims] 1. Various hydraulic actuators mounted on a construction machine are divided into two groups A and B, and left and right traveling switching valves are arranged in tandem on the most upstream side of each group A and B,
Further, the other switching valves on the downstream side are arranged in parallel so that the hydraulic actuators can be operated by the first and second pumps via the respective switching valves, and the discharge side oil passages of the first and second pumps can be connected. , The pressure oils from the first and second pumps are separately passed, and the pressure oil from one of the pumps is supplied to the left and right traveling motors, and the pressure oil from the other pump is supplied to the other working hydraulic actuators. It is equipped with a traveling independent valve that enables it, and also has a throttle device that sets the engine speed to high speed and low speed, so that the signal from the throttle device is input to the controller, and the operation detection of the hydraulic actuator operation lever is detected. Means for adjusting the engine speed to a predetermined idle speed via the controller when all the operating levers are in the non-operating position, and The engine rotation in response to the work content,
In a construction machine equipped with a work mode changeover switch that can be switched between high speed, medium speed, and fine speed via a controller, a trailer load mode position change signal is provided at the change position of the work mode change switch. Is input to the controller and the controller determines based on the trailer loading mode position switching signal, the controller outputs an independent position switching command signal to the traveling independent valve, and the controller sends the engine governor to the governor. On the other hand, a trailer loading mode switching device for a construction machine, wherein a medium speed rotation maintenance command signal is output via a stepping motor.