JP2563897Y2 - Engine control device for construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION This invention relates to an engine stop device of a construction machine such as a hydraulic excavator.

2. Description of the Related Art FIG. 2 is a circuit diagram showing a conventional engine stop device 1. In the figure, 2 is a key switch, 3 is a stop control switch having a timer function, 4 is an electric motor with a reduction gear, 5 is an output shaft of the electric motor 4, 6 'is a dedicated fuel cutoff operating tool, and 7 is an output shaft. A coupling mechanism that connects the fuel cutoff operation tool 5 and the fuel cutoff operation tool 8, a power supply 8, an accelerator lever 21 for increasing or decreasing the fuel injection amount, is an operation tool that controls the engine speed within a range from an idling state to a maximum speed. . Third
The figure is a perspective view showing the periphery of the electric motor 4 and the fuel cutoff operation tool 6 '. In the figure, 9 is a fuel supply system, 10 is a fuel injection pump of the fuel supply system 9, and 11 is a lever attached to the output shaft 5 of the electric motor 4.

Next, the function of the prior art engine stop device 1 will be described with reference to FIG. When the key switch 2 is turned off to stop the engine, the operation of the stop control switch 3 having a timer function causes the electric motor 4 to operate for at least a few seconds until the engine is stopped, and the fuel cutoff operating tool 6 to operate. ′ In the fuel cut position. Then, the fuel cut-off operation tool 6 'operates to the fuel cut position to cut the fuel to the combustion chamber (not shown) of the engine. The electric motor 4 is a DC motor configured so that its output shaft 5 operates at a low speed.

Problems to be Solved by the Invention In the prior art engine stop device, the supply of fuel to the combustion chamber of the engine is cut by rotating the electric motor by turning off a key switch.

On the other hand, recent hydraulic excavators are equipped with operation mode changeover switches, controllers, stepping motors, etc.
The operation mode changeover switch can be set to one of the H position (for heavy load), S position (for normal load), and FC position (for very low speed operation) according to the work situation. I have to. That is, by switching the operation mode switch to the H position, the S position, and the FC position,
The stepping motor is operated in a stepwise manner so that the engine can be arbitrarily set to high-speed rotation, medium-speed rotation, or low-speed rotation.

In view of the above, an object of the present invention is to provide a device for stopping an engine by outputting a signal from a controller for operating mode switching to a stepping motor without using the above-described electric motor in a conventional engine stopping device. I do.

Means for Solving the Problems An engine, a fuel lever for adjusting combustion supplied to a combustion chamber of the engine, a stepping motor for operating the fuel lever, and adjusting and setting the number of revolutions of the engine according to a work situation. An operation mode changeover switch, a key switch that outputs a command signal for starting, running, and stopping the engine; and a controller that receives a changeover operation signal from the operation mode changeover switch and a command signal from the key switch. The controller includes an operation signal for starting or stopping the engine based on the command signal, and an operation signal for adjusting and setting the engine speed to a predetermined speed based on the switching operation signal. Outputs to the motor and continues the operation signal to stop the engine for a predetermined time And has a timer function of outputting the data.

Action b. When an engine stop operation is performed by a key switch, the stop signal is input to the controller, and the controller outputs a stop operation signal to the stepping motor. The stepping motor rotates and operates the fuel lever to the fuel cut position via the connection mechanism. As a result, the fuel supply is cut, and the engine can be stopped.

B. In the controller in the above item a, the stop operation signal is output to the stepping motor until the engine is stopped by the operation of the built-in timer, so that the engine is reliably stopped.

C. Since the fuel lever has both functions of the accelerator lever and the fuel cutoff operating device of the prior art, in addition to the above-described engine stop operation, the controller operates each operation in accordance with a signal for selecting the number of rotations of the engine in multiple stages. The signal is also output to the stepping motor, and the stepping motor only needs to operate a single fuel lever via the coupling mechanism, so that the electric motor used in the prior art is unnecessary.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an engine control device 12 according to the present invention.
FIG. In the figure, the same reference numerals are given to components using the same components as the conventional technology. 13 is an engine, 14 is a key switch, 15 is a controller, 17 is a stepping motor, 18 is an output shaft of the stepping motor 17, 19 is a lever attached to the output shaft 18, and 20 is a coupling mechanism.

Next, the configuration of the engine control device 12 according to the present invention will be described with reference to the drawings. Controller with timer function
15 is provided, and a stop signal from the key switch 14 is input to the controller 15. On the other hand, the fuel lever 6 arranged in the fuel supply system 9 of the engine 13 and the output shaft 18 of the stepping motor 17 are connected via a connecting mechanism 20.

Next, the function of the main constituent members according to the present invention will be described in detail. The fuel lever 6 can adjust the fuel injected into the combustion chamber of the engine in a wide range from the maximum to no injection by rotating the fuel lever 6. The fuel injection pump 10 'of the related art has a function of both the fuel cut-off operation tool 6' and the accelerator lever 21 in the conventional fuel injection pump 10 '. Further, the controller 15 steps the fuel lever 6 in accordance with the input of a switching operation signal from a mode changeover switch (not shown) in the prior art so that the engine speed becomes a preset number of stages. In addition to outputting an operation signal that can be set via the mode 4, when a stop signal obtained by operating the key switch 14 is input to the controller 15, whether the signal is continuous or not is output. Instead, the function of the built-in timer is directed to the stepping motor 17 so that the fuel lever 6 has a function of continuously outputting a stop operation signal that keeps the fuel cut position at least until the engine is completely stopped.

Next, the function of the engine control device 12 according to the present invention will be described. When the engine stop operation is performed by the key switch 14, the controller 15
Based on the signal from 14, the stop operation signal is output to the stepping motor 17 at least until the engine stops by the operation of the built-in timer after the signal disappears. As a result, the stepping motor 17 rotates,
The fuel lever 6 is operated to the fuel cut position via the connecting mechanism 20. This cuts the fuel supply,
The engine 13 can be stopped.

Since the operation mode switching function is provided to the hydraulic excavator and the fuel lever is operated by the stepping motor 17 used for this, the structure is further simplified and the number of parts is small. Moreover, since the electric motor 4 used in the prior art is unnecessary, the manufacturing cost can be reduced.

Effects of the Invention With the engine control device of the present invention, the optimum engine speed according to the work situation (heavy load work, normal load work, low speed operation, etc.) can be obtained only by operating the operation mode changeover switch. Further, the fuel supply to the engine combustion chamber can be cut by turning off the key switch. In addition, the stop function signal is output to the stepping motor until the engine is stopped by the function of the timer function, so that the engine is reliably stopped. Further, in order to obtain the above three functions, a stepping motor and a controller for switching the operation mode and an electric motor for cutting the supplied fuel are conventionally provided.
The electric motor (and related members, etc.) can be made unnecessary only by the engine start / stop function).

As described above, the engine control device of the present invention can be mounted on construction machines at extremely low cost, and does not newly occupy the space inside the vehicle body, so that the layout of other devices and the like is not hindered. Also, unlike the prior art, there is no need to separately provide an engine stop device, so that cost reduction can be achieved even in the case of new production or remodeling. Engine start / stop function (and timer function)
Can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an engine control device according to the present invention, FIG. 2 is a circuit diagram showing a conventional engine stop device, and FIG. 3 is a diagram showing a conventional electric motor and a periphery of a fuel cutoff operating device. It is a perspective view. DESCRIPTION OF SYMBOLS 1 ... Engine stop device 2, 14 ... Key switch 3 ... Stop control switch 4 ... Electric motor 6 ... Fuel lever 6 '... Fuel shut-off operating tool 7, 20 ... Connection mechanism 9 ... Fuel supply system 12… Engine control device 13… Engine 15… Controller 17… Stepping motor

Claims (1)

(57) [Scope of request for utility model registration] 1. An engine, a fuel lever for adjusting fuel to be supplied to a combustion chamber of the engine, a stepping motor for operating the fuel lever, and an operation mode for adjusting and setting the number of revolutions of the engine according to work conditions. A changeover switch, a key switch that outputs a command signal for starting, running, and stopping the engine; and a controller that receives a switching operation signal from the operation mode changeover switch and a command signal from the key switch. The controller sends an operation signal for starting or stopping the engine based on the command signal and an operation signal for adjusting and setting the engine speed to a predetermined speed based on the switching operation signal to the stepping motor. And an operation signal for stopping the engine is continuously output for a predetermined time. Construction machine engine control apparatus characterized by having a timer function.