JPS60243365A - Starter - Google Patents

Abstract

PURPOSE:To prevent the damage of a starter by a method wherein the conduction of the starter is intercepted when the heating temperature of the exciting coil of a magnet switch, which is connected to a starting motor, and the temperature of the starting motor are detected in that one of them or both of them have arrived at respective predetermined values. CONSTITUTION:When the starting switch 200 is switched ON, a transistor 2 in a relay 300 is put ON, thereafter, the transistor 3 is put ON after a predetermined time delay and a movable contact 1b is closed by the exciting of a coil 1a. Then, the attracting coil 10 and the holding coil 11 of a magnet switch 400 are conducted to close the movable contact 9a and the starter motor 500 is started. In this case, a normally closed bimetal 15 is opened to stop the motor 500 if the starter is driven for a long period of time without obtaining the perfect ignition of an engine and the temperature of the motor 500 is risen abnormally. In case the motor 500 is driven in no-load condition and the temperature of a normally closed bimetal 14 has arrived at a predetermined value by the self heating thereof, the normally closed bimetal 14 is opened and the motor 500 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a starter for driving an internal combustion engine.

[Prior art]

As shown in Japanese Unexamined Patent Publication No. 58-197469, the conventional one is such that the control transistor that controls the switching transistor that controls the operation of the starting relay is turned off so that it does not turn on faster than the switching transistor when the starting switch is turned on. The motor is controlled by a capacitor, and when the temperature of the starter motor reaches a predetermined temperature, it is sensed by a temperature sensor and the switching transistor is turned off, allowing the scooter to be driven under overload conditions and for long periods of time. In some cases, there is a method that can prevent starter burnout and centrifugal breakage due to overspeeding with low power consumption.

However, in the conventional system described above, after starting the internal combustion engine,
Even if the starter motor is operated without load due to a faulty turning off of the starter switch, etc., the temperature rise of the starter motor is low, and it takes a long time for the temperature sensor installed in the starter motor to reach the specified temperature that activates, resulting in no-load operation. There was a possibility that this would cause damage to the scooter motor.

[Purpose of the invention]

The present invention can prevent damage to the scooter motor when the starter motor is operated with no load.
Furthermore, since the temperature sensor is activated by the temperature generated by the temperature sensor's self-heating, a heating element for activating the temperature sensor is not required, and the number of parts can be reduced.

[Structure of the invention]

a starting switch, a magnet switch having an excitation coil activated by turning on the start switch, a starter motor connected to the magnet switch and driving the internal combustion engine, self-heating due to the current flowing through the excitation coil of the magnetic switch, When the temperature of this self-heating reaches a predetermined temperature, the power supply to the starter motor is cut off, and a temperature sensor detects the temperature of the starter motor, and when the temperature reaches a predetermined temperature, the power supply to the starter motor is cut off. A starter comprising:

〔Example〕 The present invention will be described below with reference to embodiments shown in the drawings.

As shown in FIG. 1, 100 is an on-vehicle battery. 2
00 is a start switch that works in conjunction with the key switch, and one end is connected to the battery 100. 1a is a coil of the relay 300, one end of which is connected to the starting switch 200, 1b is a movable contact that is attracted by the coil 1a, and lc is a fixed contact, one end of which is connected to the pantry 100. Reference numeral 2 denotes a switching transistor that conducts and interrupts the excitation current of the coil 1a, and a normally closed bimetal 14, which is a normally closed contact, is connected to the emitter side. Reference numeral 3 denotes a control transistor for controlling the base current of the switching transistor 2, whose emitter is grounded and whose collector is connected to the base of the switching transistor 2. Reference numeral 4 denotes a capacitor which delays the turn-on of the control transistor j compared to the switching transistor 2, and is disposed between the base and emitter of the control transistor 3. The resistor 5.6 is for controlling the base current of the control transistor 3, and the resistor 7 is for controlling the base current of the switching transistor 2. The diode 8 bypasses the surge current generated when the coil 1a is de-energized. Diode 8a is holding coil 1
1. Bypassing the surge current of the shunt coil 15 and protecting the switching transistor 2. The magnetic switch 400 has a movable contact 9a that is attracted to the attraction coil 10 and the holding coil 11 that constitute the excitation coil, and a fixed contact 9 that is connected to the battery 100 and the stark motor 500, respectively.
b, and one end of the attraction coil IO and the holding coil 11 are connected to the fixed contact 1c of the relay 300. The starter motor 500 has a field coil 12 and an armature 13 connected in series, transmits the rotation of the armature 13 to the internal combustion engine, and starts the internal combustion engine.

As shown in FIG. 2, a normally closed bimetallic holder 14 serving as a temperature sensor is held in a bimetal holder 16. Further, the holder plate 17 holding the brush 23 in contact with the commutator 22 of the armature core 13 is fixed by passing the terminal 21 through the holder plate 17 and the end frame 24 and tightening a nut 25.

Further, the terminal 21 holder plate 17 and the end frame 24 are insulated by insulating bushings 19, respectively, and the nut 25, the end frame 24, and the nut 2
5 and holder plate 17 are each insulated bushing 20.
It is insulated by 21.

The bimetal holder 16 is sandwiched between the nut 25 and the insulating bushing I8, and is held against the end frame 24.
Fixed. Moreover, one end of the normally closed bimetal 14 is
It is connected to a connection point between the shunt coil 15, which is connected to the other end of the holding coil 11, and the emitter of the switching transistor 2, and the other end is connected to ground.

Next, the operation of the above configuration will be explained. When the start switch 200 is closed, a base current flows into the switching transistor 2 via the resistor 7, and the switching transistor 2 is turned on. At the same time, the coil 1a, the resistor 6, and the capacitor 4 are energized to charge the capacitor 4, and the control transistor 3 is turned on later than the switching transistor 2.

Therefore, most of the current flows between the collector and emitter of the switching transistor 2, which was turned on first, and the coil la
The magnetic flux excited by the magnetic flux causes the movable contact lb and fixed contact 1c to
closes. When the relay 300 is turned on in this way, power is supplied from the panteri 100 to the magnetic switch 400, current flows through the attraction coil 10 and the holding coil 11, the movable contact 9a and the fixed contact 9b close, and the starter motor 500
．． starts. In this state, the potential difference between the collector and emitter of the switching transistor 2 becomes very small, and the base voltage of the control transistor 3 does not rise enough to turn on the control transistor 3, so that the switching transistor 20 remains on. Then, by starting the starter motor 500, the pinion of the armature 13 is rotated, and the internal combustion engine is driven via the ring gear. Further, when the starting switch 200 is opened, the coil 1a is quickly deenergized by the action of the diode 8, and the capacitor 4 is also discharged by the resistor 5, returning to its initial state.

Now, if the starter is driven for a long time when the engine is difficult to start, or if it is driven at low temperatures and in an overloaded state where the engine starting resistance is large, the temperature of the starter motor 500 will rise rapidly, and this heat will cause the holder plate 17 to The normally closed bimetal 14 installed at a predetermined temperature (about 150°C)
It opens when it reaches . At this time, the current flowing through the relay coil 1a and the switching transistor 2 and the holding coil 11
, the current flowing through the shunt coil 15 is a sealed bimetal I
4, promoting self-heating of the normally closed bimetal 14,
Helps increase the temperature of the normally closed bimetal 14.

Furthermore, after the internal combustion engine has started, if the armature 13 of the starter motor 500 is rotated by the internal combustion engine due to an opening failure of the starting switch 200 or the like and is operated under no load, a high voltage is applied to the suction coil 10 and the holding coil 11. The current flowing to the holding coil 11 and the shunt coil 15 increases, and overlaps with the current flowing through the coil 1a of the relay 300, and the normally closed bimetal 14 is energized for about 5 minutes, causing the normally closed bimetal 14 to become self-contained. When the temperature due to heat generation reaches a predetermined temperature (150° C.), the normally closed bimetal 14 opens.

Therefore, even if no-load operation is performed, the normally closed bimetal 14
By opening, it is possible to cut off the power supply to the starter motor 500 and prevent damage to the starter motor 50O. Further, since the normally closed bimetal 14 opens the normally closed bimetal 14 due to the temperature generated by self-heating, there is no need to provide a heating element for operating the normally closed bimetal 14.

In the above, with the start switch 200 closed,
When the hermetic bimetal 14 opens, the base current of the switching transistor 2 is cut off and turned off, so the coil 1a is deenergized, cutting off the power to the magnetic switch 400 and stopping the starter motor 500. and,
The capacitor 4 is charged via the resistor 6, the base voltage of the control transistor 3 increases, and the control transistor 3 is turned on. Next, after the starter motor 500 stops, the temperature of the starter motor 500 or the self-heating temperature of the normally closed bimetal 14 decreases to a safe range, and the normally closed bimetal 1
4 returns and closes, voltage is supplied to the base and collector of the switching transistor 2, but since the control transistor 3 is in an on state, the base of the switching transistor 2 is not supplied with power, and the coil la is movable. Since a current sufficient to attract contact 1b does not flow, starter motor 500 maintains a stopped state.

For restarting, the initial state can be returned by forcibly turning off the starter starting rotation system such as the starting switch 200.

The switching transistor 2 may be of a Darlington type, and the normally closed bimetal 14 may be a positive temperature characteristic thermistor.

Further, it goes without saying that the normally-closed bimetal 14 may be installed not only on the holder plate 17 but also anywhere on the starter motor 500 as long as it can sense the heat generated by the starter motor 500.

In another embodiment shown in FIG. 3, a temperature fuse 17 is connected between the starting switch 200, the suction coil 10, and the holding coil 11, and the temperature fuse 17 is used to sense the heat generated by the starter motor 500. It is placed where possible. Therefore, without using the relay 300, it is possible to obtain the same effects as in the above-described embodiment.

Furthermore, one end of the normally closed bimetal 14 whose other end is grounded is connected to one end of the shunt coil 15 which is connected in series with the holding coil 11 and the shunt coil 15, but is directly connected to one end of the holding coil 11. May be connected.

Further, although the switching transistor 2, control transistor 3, and capacitor 4 of the relay 300 form the self-holding circuit of the temperature sensor, the self-holding circuit of the temperature sensor may also be formed using a cyrisk or the like.

〔Effect of the invention〕

As described above, in the present invention, due to self-heating caused by the current flowing through the excitation coil of the magnetic switch, when the temperature of this self-heating reaches a predetermined temperature, the power supply to the starter motor is cut off, and the temperature of the starter motor is detected. The starter motor is equipped with a temperature sensor that cuts off the power to the starter motor when the temperature reaches a predetermined temperature.If the starter motor malfunctions, the starter motor is forced into unloaded operation, causing current to flow through the excitation coil of the magnetic switch. If the motor continues to flow, power to the starter motor will be cut off to prevent damage to the scooter motor, etc. Also, if the scooter motor generates heat due to overload operation, the power to the starter motor will be stopped to prevent burnout or overspeeding. This has the excellent effect of preventing centrifugal breakage due to heat generation with low power consumption, and since the temperature sensor is activated by the temperature generated by self-heating, there is no need to provide a heating element to activate the temperature sensor.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an embodiment of the starter of the present invention;
FIG. 2 is a partially sectional front view showing the attachment of the normally closed bimetal of the above embodiment, and FIG. 3 is an electric circuit diagram showing another embodiment of the starter of the present invention. 1-00...Battery, 200...Start switch,
400... Magnetic switch, 500... Starter motor, 10.11... Attraction coil and holding coil each forming an excitation coil, 14... Normally closed bimetal forming a temperature sensor. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] a starting switch, a magnet switch having an excitation coil activated by turning on the start switch, a starter motor connected to the magnet switch and driving the internal combustion engine, self-heating due to the current flowing through the excitation coil of the magnetic switch, When the temperature of this self-heating reaches a predetermined temperature, the electricity to the starter motor is cut off, and a temperature sensor detects the temperature of the starter motor, and when the temperature reaches a predetermined temperature, the temperature sensor cuts off the electricity to the starter motor. A starter comprising: