JPH0694857B2 - Forward and reverse engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention is for a working machine such as a digging machine that requires forward / reverse rotation, and can be switched between forward / reverse rotation in a forward or reverse direction. The present invention relates to a forward / reverse engine having a starting motor for starting.

(Prior Art and Problems to be Solved by the Invention) Conventionally, in this type of engine, the starter motor has two pushbutton switches for forward rotation and reverse rotation, or a forward / reverse switching switch. If you touch the switch after starting the engine,
The starter motor rotates, causing damage to the clutch. Especially, when a switch rotating in the opposite direction is touched, an abnormal load may be applied and the starter motor may be burned.

(Means and Actions for Solving the Problem) The present invention is provided with a rotation detecting device for detecting the rotation of an engine and interrupting the electric circuit of a starter motor at the time of rotation of the engine. Since the electric circuit of the starter motor is cut off by the operation of the rotation detecting device, the starter motor does not rotate even if the switch of the starter motor is accidentally touched by a hand.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

In the figure, a crankshaft 3 of an engine 1 that can rotate in the normal and reverse directions
A magnet wheel 5 is fixedly attached to one side of the magnet wheel 5, and an electromotive coil 7 is provided near the outer circumference of the magnet wheel 5. A centrifugal clutch 9 is provided at the end of the crankshaft 3 and is connected to a transmission shaft 11. A large gear 13 is fixed to the other end of the crankshaft 3, and a small gear 15 is meshed with it. A small gear 15 is fixed to a rotary shaft 23 connected to a drive shaft 19 of a starting motor 17 via an electromagnetic clutch 21. The starting motor 17 is a neutral position return type start / reverse switching switch for starting.
Neutral position return type switching relay that is switched by 25
The switching relay 27 is connected to the battery 33 via the contact 31 of the relay 29. The switching switch 25 has a rotation detection contact 35 and a relay 29 connected in series to a battery 33. Electromagnetic clutch 21 is connected in parallel with relay 29.
A charging connector 37 for connecting to a power source is connected to the battery 33. A spark plug 41 is provided in the secondary circuit 39 of the electromotive coil 7 that generates electromotive force in response to the magnet embedded in the outer periphery of the magnet foil 5, and the primary circuit 43 is connected to the ignition unit 45 and used for rectification. It is connected to the battery 33 via the diode 47. The ignition unit 45 is for short-circuiting the primary circuit 43 when the primary voltage reaches a predetermined voltage to cause the secondary circuit 39 to generate high voltage and to discharge the spark plug 41. Further, the rotation detection device 49 is connected to the primary circuit 43, and the pulse of the current of the primary circuit generated for each revolution of the engine is measured, and when the number of pulses in a predetermined time reaches a predetermined value, that is, the engine has a predetermined The rotation detecting contact 35 is provided to be cut off when the rotation speed is reached. An engine stop switch 51 that short-circuits the primary circuit 43 is provided. Thus, the contact 31 is closed when the circuit (first circuit) in which the contact 35 and the changeover switch 25 are connected in series is energized, and the circuit in which the contact 31 and the changeover relay 27 are connected in series (second circuit). Is turned on, and the second circuit is turned off when the first circuit is turned off.

With the above configuration, when starting the engine,
When the switching switch 25 is connected in the forward direction, the relay 29 is energized to connect the contact 31 and the electromagnetic clutch 21 is energized. At the same time, the switching relay 27 is connected to the circuit for forward rotation, and the starting motor 17 is rotated in the forward direction. The engine 1 starts to rotate in the forward direction. When the engine 1 rotates, a voltage is generated in the electromotive coil 7 in response to the magnet wheel 5, the ignition unit 45 discharges the spark plug 41, and the cylinder continues to explode. The electromagnetic clutch 21 is detected by detecting the rotation speed and disconnecting the rotation detection contact 35.
At the same time, the current of the relay 29 is cut off and the contact 31 is cut off, and the starting motor 17 is stopped. At the same time, the switching switch 25 and the switching relay 27 return to the neutral position. Engine 1
While the motor is rotating, the starting motor 17 does not rotate, but when the engine 1 is stopped, the rotation detection contact 35 is connected to restore the original state. At the time of reverse rotation, changeover switch
If 25 is operated in the reverse direction, the same operation is performed. Therefore, according to the above-described embodiment, regardless of whether the engine 1 is rotating in the normal direction or in the reverse direction, even if the changeover switch 25 is accidentally shaken by the hand during operation and the switch for the normal rotation or the reverse direction is turned on, the circuit detection device 49 causes the change. Since the contact 35 is opened and the first circuit is cut off, the contact 31 is opened and the second circuit is also cut off, so that no current flows through the starter motor 17 and it does not rotate.

〔The invention's effect〕

According to the present invention, the starting motor does not rotate while the engine is rotating, so that damage to the clutch and burning of the starting motor can be prevented.

The rotation detection device of the present invention is not limited to the configuration in which the pulse corresponding to the rotation speed is measured to detect the rotation speed as in the embodiment, but the circuit of the starter motor is cut off by detecting the voltage and the current. It may be provided in a configuration or in a configuration that mechanically interlocks with a governor or the like to shut off the switch.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention, and FIG. 2 is an explanatory view of an electric circuit. 1 …… Engine 17 …… Starting motor 49 …… Rotation detector

Claims (1)

[Claims] 1. A forward / reverse changeover switch 25 operated by a changeover operation from a contact 35 and a neutral position in an engine for forward / reverse rotation equipped with a starting motor 17 for switching forward / reverse to start in a forward or reverse direction. A switching circuit for switching between the forward / reverse rotation circuit of the starter motor 17 based on the forward / reverse rotation switching of the first circuit, in which the first circuit is connected in series, and the contact 31 that closes when the first circuit is energized and that opens when the first circuit is disconnected and the changeover switch 25. A second circuit in which 27 and 27 are connected in series is provided in parallel between the power source and the ground, and a rotation detecting device 49 for detecting a predetermined rotation of the engine 1 and opening the contact 35 of the first circuit is provided. The engine for forward and reverse rotation is characterized by that.