JP4435399B2 - Engine rotation control device - Google Patents

Description

BACKGROUND OF THE INVENTION
The present invention relates to a rotation control device for a working machine drive engine provided with an electronic governor capable of electrically changing an engine speed.
[Prior art]
Conventionally, rotation control of an actuator driving engine for a working machine such as a mobile crane is performed by connecting an accelerator lever attached to the engine and an accelerator pedal of a cab via an operation device such as a cable or hydraulic pressure. Was common. In addition, many actuators for work machines, such as double-acting hydraulic cylinders that are driven by hydraulic pressure, have a predetermined operating range. For such actuators, when the operating limit is approached, the actuator is decelerated and then the limit is reached. If it was not stopped at the position, it would not only be uncomfortable and cause damage to the equipment. For this reason, the driver always pays attention to the operation position of each actuator, and when the operation limit approaches, the engine rotation must be reduced by the accelerator pedal, and the operation is accompanied by fatigue.
As a countermeasure, there is also known a device that detects the operating position of the actuator and forcibly pushes back the accelerator lever attached to the engine in a direction in which the engine speed decreases when the actuator approaches the operating limit. However, in such a device, it is difficult to adjust the section required to reduce the engine speed to a predetermined speed, and a shock due to a sudden decrease in engine speed or a slow decrease in engine speed. In other words, the engine reaches the operating limit without decreasing the engine speed up to a predetermined number of revolutions.
[Problems to be solved by the invention]
Accordingly, the present invention focuses on the situation where an engine equipped with an electronic governor capable of electrically changing the engine speed is used for driving a work implement in recent years, and provides an engine rotation control device that solves the above problems. It is what.
Further, conventionally, there has been known an apparatus configured to transmit engine power to an actuator and to provide power transmission means capable of adjusting the speed of the actuator so that the actuator is slowly decelerated and stopped when the actuator approaches an operating limit. Even in such a device, the engine speed is not controlled. Therefore, in a working machine that drives an actuator with hydraulic pressure, the amount of hydraulic oil discharged from the hydraulic pump is not constant, and stable slow deceleration stop control that is not affected by the accelerator operation cannot be achieved.
Therefore, another object of the present invention is to provide a control device with more excellent characteristics by combining the engine rotation control device with a conventionally known actuator slow deceleration stop device.
[Means for Solving the Problems]
The invention of claim 1 of the present application relates to an engine for driving a work machine provided with an electronic governor capable of electrically changing an engine speed, an actuator driven by the engine and having a predetermined operation region, and an operating position of the actuator. The controller comprises an operating position detecting means for detecting, and a controller. The controller receives an operating position signal of the actuator by the operating position detecting means, and when the actuator is close to the operating limit, the controller controls the electronic governor with the engine speed. An engine speed reduction signal for reducing the engine speed to a predetermined low speed is output.
With this configuration, when the operating limit of the actuator approaches, the engine speed is controlled to be reduced to a predetermined low-speed rotation, so that the speed of the actuator is reduced.
Furthermore, the invention of claim 2 of the present application is directed to an engine for driving a work machine having an electronic governor capable of electrically changing an engine speed, an actuator driven by the engine and having a predetermined operation region, and operation of the actuator An operating position detecting means for detecting a position, a power transmitting means for transmitting the engine power to the actuator and adjusting the speed of the actuator, and a controller, wherein the controller is an operating position of the actuator by the operating position detecting means. When the signal is input and the actuator is near the operating limit, an engine speed reduction signal for reducing the engine speed to a predetermined low speed is output to the electronic governor and the actuator is slowed down to the power transmission means. Configured to output a deceleration stop signal And features.
With this configuration, the engine speed control can be simultaneously performed in addition to the conventional slow deceleration stop control of the actuator.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a block diagram of an actuator slow deceleration stop device for a work vehicle using an engine rotation control device according to an embodiment of the present invention.
(Engine rotation control part)
Reference numeral 1 denotes an engine for driving a work machine including an electronic governor 2 that can electrically change the engine speed. The engine 1 drives a hydraulic pump 3, and hydraulic oil discharged from the hydraulic pump 3 is sent to an actuator 5 via a hydraulic pilot type switching valve 4. The actuator 5 has a predetermined operating region, and an example of a double-acting hydraulic cylinder is shown in the present embodiment. Reference numeral 6 denotes an operation position detecting means for detecting the operation position of the actuator 5. Specifically, a length detector or the like is used as the operating position detecting means 6.
8 is an operation lever of the actuator 5, and 9 is a pilot valve operated by the operation lever 8. The pilot valve 9 is connected to the pilot switching valve 4 through pilot oil passages 10 and 11, and the pilot switching valve 4 can be switched by operating the operation lever 8.
Reference numeral 14 denotes an accelerator operation means for detecting the operation amount of the accelerator pedal 15. Specifically, a potentiometer or a rotary encoder that detects the rotation angle of the accelerator pedal 15 is used. A controller 16 receives an accelerator operation signal from the accelerator operation means 14 and sends an engine speed signal to the electronic governor 2. Normally, the controller 16 sends to the electronic governor 2 an engine speed signal that increases or decreases in response to an accelerator operation signal that increases or decreases according to the depression angle of the accelerator pedal 15. That is, according to the operation amount of the accelerator pedal 15, the rotation speed of the engine 1 increases and decreases, and the discharge amount of the hydraulic pump 3 also increases and decreases, thereby adjusting the driving speed of the actuator 5.
The controller 16 receives an operating position signal of the actuator 5 from the operating position detecting means 6, and an engine that reduces the engine speed to a predetermined low speed with respect to the electronic governor 2 when the actuator 5 reaches the operating limit. It is configured to output a rotation speed reduction signal. That is, even if the accelerator pedal 15 is fully depressed and the accelerator operation signal corresponding to the accelerator operation means 14 is sent from the accelerator operation means 14 to the controller 16, the engine speed is set to a predetermined low speed when the actuator 5 comes close to the operating limit. Therefore, the driving speed of the actuator 5 is reduced.
Therefore, even when the actuator 5 reaches the operating limit (when the double-acting hydraulic cylinder reaches the stroke end), it does not generate a large shock, and there is no possibility of damaging related equipment. .
FIG. 2 is a graph illustrating the contents of control of the engine speed by the engine rotation control device described above. When an engine speed reduction signal is output from the controller 16 to the electronic governor 2 at a position P1 near the operation limit of the actuator 5 for the engine 1 rotating at the engine speed Ne according to the operation by the accelerator pedal 15. The engine speed is reduced to the idling speed Ni at the position P2 of the operation limit of the actuator 5. As described above, since the engine speed can be gradually reduced with the passage of time, the actuator 5 can be gently decelerated, and the shock when the actuator 5 reaches the operating limit can be avoided. . Further, as shown by the two-dot chain line in the graph, if the reduction of the engine rotation is started from the point of the operating position P3 of the actuator 5 further ahead of the point of the position P1, the engine rotation can be reduced more gently. It is also possible. Thus, in the engine control of the present invention, it is possible to arbitrarily set the degree of deceleration of engine rotation. The above embodiment corresponds to the invention described in claim 1.
(Actuator slow deceleration stop control part)
Reference numerals 12 and 13 shown in FIG. 1 are electromagnetic proportional pressure reducing valves interposed in the pilot oil passages 10 and 11. When a pressure reduction command signal is sent to the electromagnetic proportional pressure reducing valves 12 and 13, the pilot pressure applied to the pilot type switching valve 4 can be reduced regardless of the pilot pressure from the pilot valve 9. It is also possible to return the switching valve 4 to the fully neutral position. The electromagnetic proportional pressure reducing valves 12 and 13 are configured to perform a pressure reducing operation in response to a pressure reducing command signal from the controller 16.
FIG. 3 is a graph illustrating the control contents of the actuator speed. The hydraulic oil discharged from the hydraulic pump 3 driven by the engine 1 rotating at the engine speed Ne corresponding to the operation amount by the accelerator pedal 15 is supplied to the actuator 5 according to the switching amount of the pilot switching valve 4. The actuator 5 is driven at a driving speed Ve. When an operating position signal is output from the operating position detecting means 6 to the controller 16 and the actuator 5 is close to the operating limit, the controller 16 sends the electronic governor 2 and the electromagnetic proportional pressure reducing valves 12 and 13 to the operating position P1 of the actuator 5. An engine speed reduction signal and a pressure reduction command signal are output. Then, the actuator speed starts to decrease, becomes zero at the position P4, and stops.
The above embodiment corresponds to the invention described in claim 2, and the power transmission means described in claim 2 corresponds to the hydraulic device such as the hydraulic pump 3 and the pilot switching valve 4 shown in FIG. Yes. As described in the prior art, when the slow deceleration stop control is performed only by the electromagnetic proportional pressure reducing valves 12 and 13 interposed in the pilot oil passages 10 and 11, the oil of the hydraulic oil discharged from the hydraulic pump 3 is used. Since the amount varies depending on the engine speed at that time, the slow deceleration characteristic of the actuator 5 is kept constant even if the pilot pressure is reduced by the electromagnetic proportional pressure reducing valves 12 and 13 and the pilot switching valve 4 is switched. It was difficult. However, when the engine speed, that is, the amount of oil discharged from the hydraulic pump 3 is also controlled as in the above-described embodiment, a stable slow deceleration stop characteristic that cannot be obtained with a conventional slow deceleration stop device can be obtained. .
2 and FIG. 3 show examples in which the changes in the engine speed and the actuator speed change linearly with the operating position of the actuator, but the changes at the deceleration start point and the deceleration end point are smooth curves. Of course, it is also possible to make a change connected by. In that case, the output characteristics of the engine speed reduction signal and the pressure reduction command signal from the controller 16 may be changed in a curved manner.
【The invention's effect】
Since it is configured and operates as described above, in the invention described in claim 1 of the present application, when the operating limit of the actuator approaches, the engine speed is reduced to a predetermined low speed rotation in a predetermined actuator operating section. Therefore, the speed of the actuator is smoothly reduced. Therefore, even when the actuator reaches the operating limit (when the hydraulic cylinder reaches the stroke end), a large shock does not occur, and therefore there is no possibility of damaging the related equipment.
Further, when performing the deceleration control of the actuator by the engine rotation control device according to the first aspect of the invention, since an expensive electromagnetic proportional pressure reducing valve that is necessary in the conventional slow deceleration stop control device is not required, it is excellent in terms of cost. It is possible to construct a deceleration control device.
Furthermore, in the invention described in claim 2, in addition to the conventional slow deceleration stop control of the actuator, the engine speed control can be performed simultaneously. As a result, stable slow deceleration stop characteristics that could not be obtained with the conventional slow deceleration stop device can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram of an actuator slow deceleration stop device for a work vehicle using an engine rotation control device according to an embodiment of the present invention.
FIG. 2 is a graph illustrating details of control of engine speed.
FIG. 3 is a graph illustrating details of control of actuator speed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine, 2 Electronic governor, 3 Hydraulic pump, 4 Hydraulic pilot type switching valve, 5 Actuator (hydraulic cylinder), 6 Actuation position detection means, 8 Operation lever, 9 Pilot valve, 10 Pilot oil path, 11 Pilot oil path, 12 Electromagnetic proportional pressure reducing valve, 13 Electromagnetic proportional pressure reducing valve, 14 Accelerator operating means, 15 Accelerator pedal, 16 Controller

Claims (2)

An engine for driving a work machine having an electronic governor capable of electrically changing the engine speed, an actuator driven by the engine and having a predetermined operating region, an operating position detecting means for detecting the operating position of the actuator, and a controller And consist of
The controller receives an operation position signal of the actuator from the operation position detecting means, and outputs an engine speed reduction signal for reducing the engine speed to a predetermined low speed rotation with respect to the electronic governor when the actuator is near the operation limit. An engine rotation control device configured to output. An engine for driving a work machine having an electronic governor capable of electrically changing the engine speed, an actuator driven by the engine and having a predetermined operating region, an operating position detecting means for detecting an operating position of the actuator, and the engine Power transmission means capable of transmitting the power of the actuator to the actuator and adjusting the speed of the actuator, and a controller.
The controller receives an operation position signal of the actuator from the operation position detecting means, and outputs an engine speed reduction signal for reducing the engine speed to a predetermined low speed rotation with respect to the electronic governor when the actuator is near the operation limit. An engine rotation control device configured to output a slow deceleration stop signal of the actuator to the power transmission means.

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