JPH02290142A - Starter protective device for vehicle - Google Patents

Abstract

PURPOSE:To prevent a motor from thermal damage by detecting the temperature of the brush of the motor of a starter, and moving a pinion of the starter interlocking with a ring gear of an engine widthwise according to the temperature to release the interlock. CONSTITUTION:A temperature sensor 9 for detecting the temperature is placed to a brush 3 of the motor of a starter 10. A controller 22 controlling a coil current by the temperature sensor 9 mentioned above is provided to the end of a coil 12 of a magnetic switch 11. Where, when the temperature of the motor of the starter 10 rises, the temperature of the brush 3 increases with the increasement thereof. The temperature sensor 9 detects the temperature, and a circuit of the coil 12 of the magnetic switch 11 pushing out a pinion 16 widthwise through the controller 22 by the temperature to be detected is turned OFF. The pinion 16 is moved widthwise by force of a spring of a flanger 13 to release interlock with a ring gear 18. By use of the constitution, the motor can be prevented from damage caused by heat thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protection device for a motor portion of a starter, and particularly to a structure suitable for preventing heat damage during overload or long-term operation.

[Conventional technology]

Conventional devices are disclosed in Japanese Utility Model Publication No. 62-4688 and
As stated in the Hitachi Electrical Components Manual, the engine and starter were designed to prevent damage to mechanical parts during operation.

[Problem to be solved by the invention]

In the above conventional technology, the starter does not start the engine, so the motor with a short-time rating is operated for a long time, or an overload is applied to the starter due to some kind of problem, which causes the motor to run overload and heat up. For physical damage,
No consideration was given.

(Means for solving the problem) The above purpose is to detect the brush temperature of the starter motor part and move the starter pinion that is meshed with the ring gear of the engine in the axial direction to release the mesh state. This is achieved by

[Effect]

When the humidity of the starter motor increases,
The temperature of the brush also increases.

A sensor for detecting temperature is provided on the brush.

By turning off the magnetic switch that pushes the pinion in the axial direction using the temperature sensor via the control means, the pinion can be disengaged from the ring gear.

〔Example〕

Fig. 1 shows one embodiment of the present invention 6 1 is a motor armature, 2 is a funmitator, 3 is a brush, 4 is a brush boulder, 5 is a rear cover, 6 is a yoke, 7 is a field coil, and 8 is a bush. It is a metal fitting made of copper, and is integrally molded with the brush 3.

9 is a temperature sensor, which is an NTC type thermistor.

FIG. 2 shows a system when the starter according to the present invention is attached to an engine.

In FIG. 2, 1o is a starter, and 11 is a magnetic switch, which functions to open and close the main current of the motor and to move a pinion 16 back and forth in the axial direction via a plunger 13 and a shift lever 16. A coil 12 serves to excite the magnet that moves the plunger 13.

14 is a contact that opens and closes the main current of the motor. Therefore, the motor is turned on and off by the contact l4, and the pinion 16 is moved in the axial direction by the plunger 13, both of which are controlled by turning the coil 12 on and off.

l7 is the engine ring gear, and 18 is the starter relay, which controls the magnetic switch 11. l9 is the excitation coil of the relay. 20 is the battery, 21 is the key switch to turn on the power to the coil 12 of the magnetic switch 1L.
, has the effect of turning OFF.

Reference numeral 22 denotes a control device, which is arranged on the ground side of the coil 12.

Figure 3 shows the characteristics of the temperature sensor 9.
In the case of type thermistors, the characteristics tend to be as shown in the figure. If the resistance is Rl when the temperature is Tl, then the temperature is Tl.
2, the resistance decreases to R2.

FIG. 4 shows the internal circuit of the control box 22.
is a diode, 24.25 is a resistor, 26 is a power transistor, and 27 is a diode.

The temperature sensor 9 is connected in parallel to the resistor 25. Diode 27 protects power transistor 26.

Since the temperature sensor 9 is configured as described above, when the temperature of the brush 3 increases, the internal resistance of the NTC type thermistor 9 decreases, and most of the current flowing through the resistor 24 is
The current flows through the diode 23, the temperature sensor 9l, the brush 3, and the armature 1, and the base current of the power transistor 26 decreases via the resistor 25.

Therefore, the power transistor 26 is turned OFF, and the current in the coil 12 of the magnetic switch is also turned OFF.

Next, the operation will be explained.

When the key switch 21 is turned on to start the engine, the battery 20 connects the coil 12 of the magnetic switch 11 to the power transistor 26 of the control device 1ii22.
, Close the earth circuit. The magnetic switch 11 is activated, the plunger 13 is attracted, and the shift lever 15 is
The pinion 16 connects to the ring gear 18 of the engine 17 via
It is meshed with. Contact 14 is ONL, battery 20 is connected to starter motor field coil 7, brush 3L commutator 2,
Armature 1 is energized and the motor rotates. The engine starts rotating with the power of this motor. When the engine starts, the key switch 21 is set to 01.'[', so the coil 12 of the magnetic switch 11 is set to
Therefore, the plunger];3 returns to its original position by the force of the spring. Therefore, the pinion 16 also disengages from the ring gear 18 and returns to its original position.

Here, the current flowing to the motor is closely related to the load on the engine 17, and as the engine load increases, the current also increases. As the current increases, heat generation due to Joule heat also increases, and the temperature of the motor's field coil 7, brush 3, commutator 2, and armature 1 also increases. Therefore, if the engine load increases significantly or if the engine is operated for a long time without starting due to some kind of problem, the Joule heat will also increase, causing heat damage to the current-carrying member.

In this case, the device operates as follows.

When the temperature of the brush 3 increases, the temperature of the bush 8 also increases.
Therefore, the resistance of the temperature sensor 9 also decreases due to the characteristics shown in FIG. Assuming that once in steady state is T1 and the limit temperature at which heat damage occurs is T2, the resistance is R.
l, R2.

Therefore, when the resistance of the temperature sensor 9 reaches R2, the power transistor 2
6's base current decreases, power 1-transistor 26
If it is set to turn OFF, the circuit of the coil 12 of the magnetic switch 11 will be turned OFF, the contact 14 will be set to ○FFL, the plunger 13 will also return to its original position, and the pinion 16 will also mesh with the ring gear 18. Release and stop.

As a result, not only can loss of the starter due to heat damage be prevented in advance, but also a highly safe system can be achieved.

〔Effect of the invention〕

Since the temperature rise in the motor section can be reliably controlled, inexpensive insulating materials can be used, and the starter can be made smaller and lighter at low cost.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the motor section of the starter according to the present invention, Fig. 2 is a system diagram for engine starting according to the present invention, Fig. 3 is a characteristic diagram of the temperature sensor, and Fig. 4 is a control including the temperature sensor. It is a figure showing an apparatus. 1... Armature. 3...Brush. 8... Bush, 9... Temperature sensor, 10... Starter, 11...
...Magnetic switch, 12...Coil, 13.
...Plunger, 14...Contact, 16...Pinion, 18...Ring gear, 20...Battery, 21...
・Key switch. Part B

Claims (1)

[Claims] 1. A pinion is engaged with a ring gear of an engine via a shift lever and a plunger of a magnetic switch, and power is supplied to a motor via a contact point of the magnetic switch, so that the motor is powered by the power of the motor. In a starter for starting an engine, a temperature sensor is fixed to the brush, and means is provided at one end of the coil of the magnetic switch to control the coil current by the temperature sensor, so that the pinion is moved relative to the ring gear depending on the brush temperature. A starter protection device for a vehicle that is characterized by engaging and disengaging. 2. In claim 1, the temperature sensor includes NT.
A starter protection device for vehicles characterized by the use of a C-type thermistor. 3. A starter protection device for a vehicle, characterized in that a control means using a temperature sensor is provided on the ground side of the coil of a magnetic switch. 4. A starter protection device for a vehicle, characterized in that a temperature sensor is screwed and fixed to a metal bush integrally formed with a brush. 5. A starter protection device for a vehicle, characterized in that a temperature sensor is arranged in series with an armature circuit.