JPH11148449A - Starter protecting relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the longest operation time of a starter according to the atmospheric temperature condition, as well as to realize the small size and the light weight of the starter, by preventing a severe use of the starter by a user. SOLUTION: In this starter protective relay 1, a transistor 13 to drive a relay 2 is provided, a battery voltage is applied to the starter side through the relay 2 by closing a key switch, and the engine is started. In this case, a timer circuit 3 to make the operation of the transistor 13 to drive the relay 2 impossible, after the first specific time has passed from the close of the key switch, and to restore the operation of the transistor 13, after the second specific time has passed from the open of the key switch, and a thermister 21 to detect the atmospheric temperature are provided, and the first and the second specific times are made as increasing functions to the atmospheric temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter protection relay, and more particularly to a starter protection relay for preventing a starter from being used for a long time.

[0002]

2. Description of the Related Art When starting an engine of a vehicle, a user turns a starter beyond a rated time for a short-time rated starter, or turns the starter again without a predetermined time when starting fails. Or severe use. Conventionally, the starter side is designed with a sufficient margin for the heat capacity and the like in consideration of the above.

[0003]

In recent years, the movement to prevent environmental destruction has been strengthened, and the weight reduction of automobiles has been promoted due to exhaust gas regulations and the like, and there has been a strong demand for smaller and lighter starters. It goes without saying that the quality must be ensured even in the case of the reduction in size and weight in view of the safety imposed on the automobile. Therefore, in order to meet the market demand for smaller and lighter while ensuring the quality of the starter,
It is considered that electronic equipment is added in consideration of various uses of the user.

The present invention has been made in view of the above points, and has as its object to provide a starter protection relay for setting the longest operation time of a starter.

[0005]

In order to solve the above-mentioned object, a starter protection relay according to the present invention includes a switching element for driving the relay, and when a key switch is turned on, a battery voltage is supplied to the starter through the relay. In the starter protection relay for supplying and starting the engine, after the first predetermined time has elapsed from the turning on of the key switch, the operation of the switching element for driving the relay is disabled, and the second predetermined time has elapsed since the opening of the key switch. After the lapse of time, a timer circuit for restoring the operation of the switching element and a temperature detecting element for detecting the ambient temperature are provided, and technical means for increasing the first and second predetermined times with respect to the ambient temperature are employed. did.

This temperature detecting element includes a temperature-resistance changing element connected between the base and the emitter of a transistor provided in the timer circuit for controlling the switching element.

[0007]

FIG. 1 is a circuit diagram showing an embodiment of a starter protection relay according to the present invention, and FIG.
The time characteristic is shown.

In FIG. 1, 1 is a starter protection relay,
2 is a relay, 3 is a timer circuit, 11 is a relay drive coil, 12 is a normally open contact, 13 to 15 are transistors,
16 and 17 are diodes, 18 and 19 are constant voltage diodes, 20 is a capacitor, 21 is a thermistor as a temperature-resistance change element, and 22 to 25 are resistors.

[0009] A user operates a key switch (not shown) of the vehicle.
Is turned on, the vehicle battery (not shown) is connected to the SW terminal.
From the battery voltage.

When the battery voltage is applied to the SW terminal as described above, the transistor 13 is turned on because the base current is supplied via the resistor 22, and the relay drive coil 11 of the relay 2 is energized, and The open contact 12 is closed, and the B terminal and the C terminal are connected. A battery (not shown) of the vehicle is connected to the B terminal, and a starter (not shown) is connected to the C terminal, whereby the battery voltage is supplied to the starter side, and the starter starts rotating.

At the same time, when the battery voltage is applied to the SW terminal by turning on the key switch, a stabilizing voltage is supplied to the timer circuit 3 from the internal stabilizing circuit including the resistor 23 and the constant voltage diode 18, The capacitor 20 starts charging via 24. After a certain time, the charging voltage of the capacitor 20 exceeds the sum of the Zener voltage of the constant voltage diode 19 and the base-emitter voltage of the transistor 14, and the transistor 1
Since the base current of No. 4 flows, the transistor 14 is turned on. A collector current flows from the internal stabilizing circuit via the diode 17 to the transistor 14, supplies a base current of the transistor 15 in the next stage and turns on, thereby absorbing the base current of the transistor 13 and 13 is forcibly turned off. As a result, the relay drive coil 11 of the relay 2 is deenergized, and the normally open contact 12 is opened. That is, the timer circuit 3 operates from the time when the battery voltage is applied to the SW terminal, and the battery voltage is not supplied to the starter side after a predetermined time such as 30 seconds has elapsed.

Therefore, even if the user attempts to turn the starter continuously for more than a predetermined time (for example, 30 seconds), the power supply of the starter is stopped when the predetermined time (for example, 30 seconds) has elapsed, and the subsequent operation is stopped. Impossible. Therefore, the starter does not generate any more heat, so that there is no subsequent rise in temperature, and thereafter, the heat is directed to heat dissipation, so that severe use of the starter can be prevented.

When the engine starts, the user returns the key switch, and when the key switch is opened, the battery voltage applied to the SW terminal and the stabilization voltage of the timer circuit 3 disappear. The electric charge charged in the capacitor 20 is discharged through the resistor 24, but even if the user immediately turns on the key switch, the transistor 14 is turned on. The transistor 13 for driving the relay 2 is kept off, and the relay coil 11 of the relay 2 is not energized. That is, even if the normally open contact 12 is not closed and the battery voltage is applied to the starter protection relay 1 from the SW terminal,
The battery voltage is not supplied to the starter side, and the starter cannot be turned.

When the timer circuit 3 is operated once and the user turns on the key switch to restart the engine before the electric charge charged in the capacitor 20 is completely discharged through the resistor 24, Although the above-mentioned predetermined time (for example, 30 seconds) generated by the timer circuit 3 is shorter than the above, when the heat radiation of the starter is not complete, the above-mentioned predetermined time generated by the timer circuit 3 is the initial time. In such a case, the residual heat of the starter may be accumulated, and when the starter is restarted, it is more advantageous for the starter that the predetermined time generated by the timer circuit 3 is gradually reduced.

The amount of heat generated when the starter attempts to start the engine changes due to friction of the engine. This may be considered to be larger as the ambient temperature becomes lower due to the influence of the viscosity of the engine oil and the like. Therefore, from the viewpoint of the operation time of the starter, for example, a starter that can be operated for 2 minutes when the ambient temperature is 25 degrees Celsius is 20 seconds to 3 seconds when the ambient temperature is minus 30 degrees Celsius.
It has been found by experiments of the inventor and the like that the operation reaches about the heat resistance limit in about 0 seconds. In determining the predetermined operation time of the starter described above, it is necessary for the starter to guarantee safe and reliable operation at severe low temperatures, taking into account the overall conditions of the vehicle and the starter. In a so-called room temperature range of about degrees, there is a margin in the heat capacity for a predetermined time in the low temperature range. Therefore,
By setting the longest operation time of the starter according to the ambient temperature conditions, it is possible to exhibit the maximum capacity of the starter.

The time factor of the timer circuit 3 is determined by the on / off timing of the transistor 15 with respect to the charge (terminal voltage) stored in the capacitor 20 by the RC charging / discharging circuit including the resistor 24 and the capacitor 20.
Therefore, changing the value of the resistor 24 has been used to change the time. However, to change the resistance slightly depending on the temperature, a complicated circuit configuration had to be used, which required a large number of components and took a long time to adjust at the time of shipment from the factory, resulting in an increase in cost. .

In the present application, the following point has been solved as a means for improving this point. That is, ON / OFF of the transistor 15 is strongly affected by the state of the transistor 14 in the preceding stage. That is, whether the terminal voltage of the capacitor 20 causes the transistor 14 to transition from off to on is most affected by the zener voltage of the constant voltage diode 19, and in this embodiment, the zener voltage of the constant voltage diode has a constant of several volts. When the terminal voltage of the capacitor 20 approaches the zener voltage of the constant voltage diode 19, a small current starts to flow due to the so-called shoulder characteristic of the constant voltage diode. The current at that time is the resistance 25 and the thermistor 2
A voltage corresponding to a division ratio of 1 is applied between the base and the emitter of the transistor 15. That is, the on / off timing of the transistor 15 is determined by a voltage corresponding to the voltage dividing ratio of the resistor 21 and the thermistor 21 of the voltage obtained by subtracting the base-emitter voltage of the transistor 14 and the Zener voltage of the constant voltage diode 19 from the terminal voltage of the capacitor 20. It is determined.

FIG. 2 shows temperature-time characteristics of this embodiment. Since the resistance value of the thermistor 21 decreases with respect to the ambient temperature rise, the time required for the transistor 15 to transition from off to on becomes longer, and has the characteristics shown in the drawing.
Note that the predetermined time only needs to have a relationship of an increasing function, and may be a case where the curve has a partially straight section or a simple increasing straight line.

[0019]

According to the present invention, there is provided a starter protection relay which includes a switching element for driving a relay, supplies a battery voltage to a starter side via this relay when the key switch is turned on, and starts the engine. A timer circuit for disabling the operation of the switching element that drives the relay after the first predetermined time has elapsed, and restoring the operation of the switching element after the second predetermined time has elapsed from the opening of the key switch; A temperature detecting element for detecting a temperature is provided, and the maximum operation time at the ambient temperature around the starter is set by setting the first and second predetermined times to an increasing function with respect to the ambient temperature. It is possible to provide a small and light starter with high safety while pulling it out.

Further, since the temperature-resistance changing element connected between the base and the emitter of the transistor for controlling the switching element provided in the timer circuit is employed as the temperature detecting element, the timer circuit requires a small number of parts. Can be realized, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit configuration of an embodiment of a starter protection relay according to the present invention.

FIG. 2 is a temperature-time characteristic diagram of a starter protection relay according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Starter protection relay 2 ... Relay 3 ... Timer circuit 13 ... Switching element 15 ... Transistor 22 ... Capacitor 21 ... Temperature detection element

Claims (2)

[Claims] 1. A starter protection relay comprising a switching element for driving a relay, supplying a battery voltage to a starter side via the relay by turning on a key switch, and starting an engine. A timer circuit for disabling the operation of the switching element for driving the relay after a lapse of time and restoring the operation of the switching element after a lapse of a second predetermined time from the opening of the key switch; And a temperature detecting element for detecting the start time, wherein the first and second predetermined times have an increasing function relationship with respect to the ambient temperature. 2. The temperature detecting element according to claim 1, wherein the temperature detecting element is a temperature-resistance change element connected between a base and an emitter of a transistor provided in the timer circuit and controlling the switching element. Starter protection relay.