JPH03525Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a starter protection device for an engine, and in particular, when the starter motor cannot rotate for some reason and is left in a locked state for a predetermined period of time. The present invention relates to a starter protection device having a function of stopping the operation of a starter.

BACKGROUND ART In general, with respect to engines and storage batteries installed in automobiles, for example, when the engine becomes overloaded due to poor engine operation or insufficient charging of the storage battery, or when the engine oil load increases at low temperatures, , the starter motor is loaded beyond its permissible torque, so that the starter motor is unable to rotate and is in a locked state. On the other hand, since starters are designed for short-time ratings, if the above-mentioned locked condition continues for a long time, the starter motor may burn out due to heat generation, eventually leading to a fire. Therefore,
It is desirable that the starter motor be released from such a locked state as soon as possible.

Fig. 2 is a signal waveform diagram showing the case where the starter motor is locked when starting the engine, and A indicates the ON/OFF state of the starter switch;
B is the rotation state of the starter motor, C is the load current of the starter motor, D is the output voltage of the storage battery,
are shown respectively.

As shown in the figure, after the starter switch is turned on and the starter motor starts rotating, the rotational state of the starter motor changes abnormally and becomes locked at time _t1 , and the motor load current rapidly increases. ,
A constant restraint current value is shown until the restraint state is released at time t ₂ (period T). Therefore, the output voltage of the storage battery continues to be in a correspondingly low voltage state.

Purpose of the invention As mentioned above, the present invention focuses on the characteristic that while the starter motor is in a locked state, the output voltage of the storage battery decreases and continues in a low voltage state,
It is an object of the present invention to provide a starter protection device capable of stopping the operation of the starter when such a low voltage state exceeds a predetermined time.

Summary of the invention The present invention uses a comparator to compare the reference voltage and the output voltage of the storage battery to detect a starter/motor locked state caused by an abnormal load. The period in which the low voltage state is expected to continue due to the decrease in voltage is detected by the restraint state detection circuit as a restraint detection state, and when the restraint state exceeds the scheduled period, the comparator outputs a signal indicating the restraint detection state. , a starter protection device configured to stop the operation of a relay device that controls the operation of a starter.

Description of Examples A starter protection device normally operates a relay device using the output from a storage battery to start starter operation by turning on the starter switch of the engine, and detects a voltage according to the engine speed. And when this voltage exceeds the expected level,
That is, when the engine is in normal operating condition,
It functions to stop the operation of the relay device and stop the operation of the starter.

In the illustrated embodiment, a starter protection device 1, a starter 2, a storage battery 3, and a starter switch 4 are shown. Furthermore, the starter protection device 1 includes a relay device 5 for actuating the starter 2; a relay drive circuit 6 consisting of transistors Q ₁ and Q ₂ connected in Darlington for controlling the operation of the relay device 5; and a comparison device consisting of an operational amplifier OP. Unit 7; operational amplifier OP consisting of resistors R ₁₁ and R ₁₂ and Zener diode Z ₂
or a comparator power supply circuit 8; a comparator reference voltage setting circuit 9 consisting of resistors _R9 and _R10 , a capacitor _C2 , and a Zener diode _Z1 ; a storage battery voltage detection circuit 10 consisting of resistors _R4 and _R5 ; A comparison voltage holding circuit or restraint state detection circuit 11 is provided, which includes resistors R ₆ , R ₇ and R ₈ , a diode D ₄ and a capacitor C ₁ .

First, when the starter switch 4 is turned on, the output voltage of the storage battery 3 is applied to the terminal S of the starter protection circuit 1. Therefore, the first input of comparator 7,
That is, the power supply circuit 8 is connected to the inverting input of the operational amplifier OP.
A reference voltage V _REF is applied via the reference voltage setting circuit 9 . The reference voltage V _REF is maintained at the Zener voltage of the Zener diode Z ₁ of the reference voltage setting circuit 9, and its specific value is as described above.
When the output voltage of the storage battery continues to be in a low voltage state while the starter motor is placed in a locked state, the low voltage level is detected. Shown as _REF .

At the same time, the second input of the comparator 7, that is, the non-inverting input of the amplifier OR, is connected via the voltage detection circuit 10 and the diode _D2 to detect the voltage of the storage battery 3 divided by its resistors _R4 and _R5 . A voltage V _D is given. At this time, the detection voltage V _D is set in advance with respect to the reference voltage V _REF so that V _D >V _REF .
Incidentally, the capacitor C ₂ of the reference voltage setting circuit 9 is provided to ensure that V _D >V _REF in the above-mentioned initial state.

The comparator 7 outputs a "high" level signal depending on the state of V _D >V _REF . Therefore, the transistor Q ₂ and the transistor Q ₁ are turned on in sequence, and the coil L ₁ of the relay device 5 is energized. Therefore, the contact CT ₁ of the relay device 5 is in a closed state.

Due to the closed state of contact CT ₁ of relay device 5, current flows from storage battery 3 through terminals B and C to coils L ₂ and L ₃ of relay device 12 of starter 2,
Its contact CT ₂ becomes closed. Note that the coil L ₂ is a contact actuation coil, and the coil L ₃ is a contact holding coil. As a result, the motor M of the starter 2 rotates, causing the engine (not shown) to start rotating.

Further, when the contact CT ₁ of the relay device 5 is closed, the output voltage of the storage battery 3 is applied to the comparison voltage holding circuit 11 via the terminal B. Therefore, capacitor C ₁ in this circuit connects to resistor through diode D ₄ .
It is charged to the voltage divided value V _C by R ₇ and R ₈ .
This charging voltage V _C is set in advance so that V _C >V _REF . Therefore, in the state described above, the output of the comparator 7 is held at a "high" level, and the contact CT of the relay device 5 is ₁ in the closed state.

Although the specific configuration is not shown and omitted, if the engine is in a normal operating state, in other words, if it is detected that the voltage corresponding to the engine speed exceeds a predetermined level, Forcibly turn off transistors Q ₂ and Q ₁ of relay drive circuit 6
Then, the operation of the relay device 5 is stopped. Therefore,
The operation of the starter 2 is stopped when the engine is in a normal operating state.

Next, a case will be described in which the motor M is placed in a restrained state while the starter 2 is in operation.

When the starter motor M becomes unable to rotate due to its abnormal load and is placed in a locked state, the load current increases and the output voltage of the storage battery 3 decreases, as described above. When the detection voltage V _D of the storage battery voltage detection circuit 10 becomes lower than the reference voltage V _REF (V _D < V _REF ),
If the comparative voltage holding circuit 11 were not provided, the output of the comparator 7 would be inverted from the "high" level to the "low (L)" level. However, the capacitor C ₁ of the comparative voltage holding circuit 11 is already in a charged state, and its charging voltage V _C indicates V _C >V _REF . Therefore,
At the second input _of the comparator 7, the discharge voltage is diode
Since the input state of comparator 7 is maintained through _D3 , its output is still in the "high" state. In this way, the above-mentioned scheduled period during which the second input voltage of the comparator 7 is temporarily held at the reference voltage V _REF is defined as the locked state detection period of the motor M, and specifically, , is set equal to period T in FIG. 2D.

As a result, if the locked state of the motor M does not exceed the detection period, the output of the comparator 7 is at a "high" level, so the relay device 7 is in the operating state and the starter 2 ignores the abnormal state. operation continues. However, when the locked state of the motor M exceeds the detection period T, that is, the comparison voltage holding circuit 11
If the constraint state continues even after the discharging effect of the capacitor C ₁ is exhausted, the output of the comparator 7 is inverted from the "high" level to the "low" level because the detection voltage V _D <the reference voltage V _REF . For this reason the transistor
Q ₂ and Q ₁ are sequentially turned off to stop energizing the coil L ₁ of the relay device 5. Therefore, the contact CT ₁ of the relay device 5 becomes open, and the operation of the starter 2 is stopped. As a result, the restrained state of the starter motor M is released, and heat generation and burnout thereof are effectively prevented.

Note that when the starter 2 stops operating, the voltage of the storage battery ₃ rises instantaneously, and the increased value is applied to the voltage detection circuit 10. This is achieved by providing That is, when the output of the comparator 7 is at a "low" level, the detected voltage of the voltage detection circuit 10 is
It is given by the voltage division ratio of resistors R ₄ and R ₃ , and this value is set so that V _D <V _REF .

Effects According to the present invention, the starter is
By utilizing the characteristic that when the motor is placed in a locked state, the output voltage of the storage battery decreases and continues in a low voltage state, the starter operation can be effectively stopped with an extremely simple configuration, preventing the starter from generating heat and burning out. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram showing the starter protection device of the present invention and its related devices. FIGS. 2A to 2D are signal waveform diagrams showing a case where the starter motor is locked when starting the engine. Explanation of symbols, 1: Starter protection device, 2: Starter, 3: Storage battery, 4: Starter switch, 5,
12: Relay device, 6: Relay drive circuit, 7: Comparator, 8: Power supply circuit, 9: Reference voltage setting circuit, 1
0: Voltage detection circuit, 11: Comparison voltage holding circuit (restricted state detection circuit), B, C, S, E: terminal, CT ₁ ,
CT ₂ : Contact, L ₁ to L ₃ : Coil, M: Motor, D ₁
~ _D4 : Diode, _Z1 , _Z2 : Zener diode, _C1 , _C2 : Capacitor, _R1 ~ _R12 : Resistor.

Claims (1)

[Claims for Utility Model Registration] (1) By turning on the starter switch of the engine, the output from the storage battery operates the relay device to start the starter operation, and a voltage corresponding to the rotational speed of the engine is applied. In a starter protection device that detects and stops the operation of the relay device to stop the operation of the starter when the value exceeds a predetermined level, for detecting a starter motor binding state caused by an abnormal load. a reference voltage setting circuit that provides a reference voltage of; a voltage detection circuit that detects the voltage of the storage battery in order to monitor the restrained state; a first input that receives the reference voltage of the reference voltage setting circuit; a comparator having a second input that receives a voltage; a bound state detection circuit that provides a voltage to a second input of the comparator indicating that the bound state continues for a predetermined period of time; A relay drive circuit that controls the operation of the relay device, wherein when the constraint state exceeds the predetermined period, the comparator outputs a signal indicating a constraint detection state, thereby controlling the relay drive circuit. A starter protection device characterized in that the operation of the relay device is stopped through the relay device. (2) The reference voltage of the reference voltage setting circuit is set to a level that detects a low voltage state of the storage battery caused by a locked state of the starter motor. The starter protection device according to item 1. (3) the restraint state detection circuit includes a capacitor;
The starter protection device according to claim 1 or 2, further characterized in that the scheduled period is given by the discharge time of the capacitor. (4) Any one of claims 1 to 3 of the utility model registration claim, further characterized in that the comparator has a resistor for compensating for voltage rise of the storage battery between its output and the second input. Starter protection device described in .