JPH06103019B2 - Engine starter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a PTO (Powar Take Off) for driving an external work device.
The present invention relates to an engine starting device for a vehicle having a shaft.

[Conventional technology]

For example, a PTO shaft for driving an external work device is often installed in a three-wheel or four-wheel vehicle for running on rough terrain having a wide low-pressure tire as a so-called balloon tire. The PTO shaft is a shaft that rotates according to the engine output for driving the vehicle, and various external work equipment such as a blade for grass and a sprayer can be attached to the PTO shaft as needed. That is, a vehicle having a PTO shaft can function as a multipurpose vehicle by appropriately exchanging external work equipment.

On the other hand, a vehicle having such a PTO shaft is provided with a governor mechanism for controlling the engine speed to be constant. When an external work device is attached to the PTO shaft and desired work is performed, the governor mechanism is activated to keep the rotation speed of the PTO shaft constant and enable traveling at a constant speed to stabilize the PTO work. Is being pursued.

[Problems to be solved by the invention] However, neglecting to confirm the operating state of the governor mechanism when starting the engine when trying to perform PTO work, and start the engine by driving the starter motor while the governor mechanism is inactive. It is not uncommon to let them do it. If such a situation is left unattended, the PTO shaft may be rotated at a high speed and the working machine attached to the PTO shaft may be damaged.

[Means for solving problems]

The engine starter of the present invention has been made in view of the above problems, and is provided with means for blocking the drive of the starter motor when the PTO shaft is connected to the engine and the governor mechanism is in the inoperative state.

[Action]

If the governor mechanism is inadvertently set to the "OFF" state when starting the engine when performing PTO work, the starter motor will not operate.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

FIG. 2 is a power transmission system diagram of a vehicle to which the present invention is applied, that is, a vehicle having a PTO shaft. Engine crankshaft 1
Is transmitted to the clutch 3 that engages and disengages, and the torque output by the clutch 3 is transmitted to the transmission 4 and the PTO.
It is transmitted to the shaft 8. For submission 4, high speed (“high”), low speed (“low”) or reverse (“reverse”)
If any of the gears is selected and "reverse" is selected, the rotational force in the reverse direction is directly transmitted to the differential gear 6 at a low rotational speed. When “high” or “low” is selected in the submission 4, the forward high speed or low speed rotational force is transmitted to the differential gear 6 through the forward transmission 5. In the forward mission 5, one of the first to fifth gears or neutral is selected. In the differential gear 6, either differential operation or lock is selected and transmitted to the wheels 7. In the differential gear 6, normally, "lock" is selected to stabilize traveling when traveling straight, and "operation" is appropriately selected when making a U-turn. On the other hand, “on” and “off” are also selected for the PTO shaft 8, and when “on” is selected, the rotational force output from the clutch 3 is applied to the working machine 9
When “OFF” is selected, the rotation of the PTO shaft 8 is stopped regardless of the rotation of the output shaft of the clutch 3.
Reference numeral 2 is a starter motor, which is electrically driven to forcibly rotate the crankshaft to start the engine.

FIG. 1 is a circuit diagram showing an embodiment of the present invention used in a wheel having a power transmission system as described above. Reference numeral 11 is a spark plug, 12 is an ignition coil, 13 is a CDI unit, and 14 is a charge coil, and these constitute a capacity discharge type ignition device. In addition, CDI unit 1
In the figure, 13a is a capacitor, 13b is a thyristor, and 13c.
And 13d are diodes.

A discharge circuit including a thyristor 15 and resistors 16 and 17 is connected to a connection point between the charge coil 14 and the CDI unit 13, and a gate of the thyristor 15 is connected to a connection point between the resistors 16 and 17. The collector of a switching npn transistor 18 whose emitter is grounded is connected to the connection point of the resistors 16 and 17 through a diode 30, and the thyristor 15 is turned “on” or “turned on” by the on / off control of the transistor 18. It takes one of the "off" states. The cathode side of the diode 30 is connected to the collector of the transistor 18. The base of transistor 18 is
It is connected to the collector of the npn transistor 19, and the emitter of the transistor 19 is grounded via the switch 21 which works in conjunction with the PTO shaft drive selection lever. The switch
21 switches to close when the PTO shaft drive selection lever is selected to the "drive" side. A power supply connection terminal 23 is connected via a resistor 22 to a connection point between the collector of the transistor 19 and the base of the transistor 18. A series circuit including a resistor 24 and a switch 20 that operates in conjunction with a governor mechanism selection lever is connected in parallel to the series circuit including the resistor 22, the transistor 19 and the switch 21, and the base of the transistor 19 is the switch 20. It is connected to the connection point with the resistor 24. The switch 20 performs a switching operation so as to be closed when the governor mechanism selection lever is selected to "actuate".

On the other hand, the starter button 25, the starting safety relay 26, the starter relay 27 and the starter motor 28 constitute a starting circuit. The fixed contact of the starter button 25 is connected to the power supply connection terminal 23, and the movable contact is connected to one terminal of the contact drive 26a of the starting safety relay 26. The other end of the contact drive coil 26a is connected to the connection point between the cathode of the diode 30 and the collector of the transistor 18. One end of the contact 26b of the starting safety relay 26 is connected to the movable contact of the starter button 25, and the other end is grounded via the contact driving coil 27a of the starter relay 27. Starter relay 27
One end of the contact point 27b is connected to the power supply connection terminal 23 and the other end is connected to the input terminal of the starter motor 28, and the other input terminal of the starter motor 28 is grounded.

Next, the operation of the present embodiment configured as described above will be described. When the PTO axis is selected on the "drive" side, the switch 21 is closed. When the PTO shaft is driven, the governor mechanism is normally operated, so the switch 20 is also closed. Therefore, the transistor 19 is in the "off" state,
Transistor 18 is in the "on" state. Therefore, when the starter button 25 is operated and closed in this state, a current flows through the "power supply connection terminal 23-starter button 25-coil 26a-transistor 18" to close the contact 26b. Then, "Power supply connection terminal 23-starter button 25-contact 26b-
A closed circuit called "coil 27a" is formed, a current flows through the coil 27a, and the contact 27b is closed. By closing the contact 27b, a current flows from the power supply connection terminal 23 to the starter motor 28, the starter motor 28 rotates, and the engine is started.

Next, a case will be described in which the governor mechanism is erroneously in the non-operating state even though the PTO shaft is in the driving state. At this time, the switch 21 is closed and the switch 20
Is open. In this case, the transistor 19 turns "on", the base potential of the transistor 18 drops, and the transistor 18 turns "off". Therefore, even if the starter button 25 is operated to close it, no current flows through the coil 26a. As a result, the contact 26b is held in the open state, and the contact 27b is also held in the open state, so that the starter motor 28 is not driven.

When the PTO axis drive selection lever is selected to the "non-drive" side, the switch 21 is open from the beginning, so the transistor 18 is "on" regardless of the state of the switch 20, and the starter button By closing 25, a current flows through the coil 26a, and the starter motor 28 is normally driven.

Further, in this embodiment, when the transistor 18 is “on”, the thyristor 15 is “off”, and when the transistor 18 is “off”, the thyristor 15 is “on”.
When the transistor 18 is "off", such as when the PTO shaft is in a drive state and the governor mechanism is inactive, the thyristor 15 turns "on" and the charge coil
The electromotive force generated at 14 is grounded via thyristor 15.
Therefore, the electromotive force of the charge coil 14 is the CDI unit 13
It is not supplied to and becomes a misfire.

〔The invention's effect〕

As described above, according to the engine starter of the present invention, the starter motor does not operate when the governor mechanism is in the “off” state at the time of engine start when performing PTO work, so the governor mechanism is in the inoperative state. The engine cannot be started even if the starter button is mistakenly operated while it is turned off. Therefore, there is no problem that the PTO shaft is rotated at high speed when the engine is started and the working machine attached to the PTO shaft is damaged.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a power transmission system diagram of a vehicle to which the embodiment in the figure is applied. 18,19 …… Transistor, 20,21 …… Switch, 25 …… Starter button, 26 …… Starting safety relay, 27 …… Starter relay, 28 …… Starter motor.

Claims (1)

[Claims] 1. In a vehicle having a PTO shaft for driving an external work equipment and a governor mechanism for maintaining a constant engine rotation speed, an electrically driven starter motor for forcibly rotating the engine to start the engine, and a PTO shaft. Is connected to the engine and means for preventing the starter motor from being driven when the governor mechanism is in the inoperative state.