JPS646342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starter protection device for a vehicle, particularly a starter protection device for a vehicle that automatically stops the operation of a starter when the engine speed of a large vehicle reaches a set value. It is related to.

Generally, when starting an engine, a starter relay is activated by closing a manual key switch, the starter is started through the contacts of the starter relay, and a pinion gear on the starter side and a ring gear on the engine side are engaged. The engine is then started. After confirming that the engine has started, opening the manual key switch turns off the power to the starter, the pinion gear protruding from the starter returns to its original position, and the starter rotates due to inertia before coming to a complete stop. That is, the driving force of the starter is transmitted to the engine through the meshing of the pinion gear and the ring gear to start the engine, and the starter returns to the stopped state. However, if the above mentioned starting is completed and the engine is rotating normally on its own, or if the engine fails to start for some reason and the starter is rotating by inertia, the manual key switch may be closed by mistake. Then, either the pinion gear on the starter side or the ring gear on the engine side will collide with each other in a rotating state, and there is a risk of damaging each of the gears.

Therefore, when the engine has successfully started and started rotating on its own, it is necessary that the starter will not start even if the manual key switch is closed by mistake, and if the engine fails to start for some reason, the starter will not start. A means must be considered to prevent the starter from starting even if the manual key switch is closed until the inertia rotation of the starter stops.

The present invention was made with the aim of solving the above-mentioned problems, and has a structure in which an operational amplifier is mainly used without using many relays, and a means for changing the voltage input to the operational amplifier is used. To provide a starter protection device for a vehicle, which is capable of opening a starter relay upon detecting that the engine speed has reached a specified value, and also preventing a so-called inertia jump phenomenon. The purpose is Examples will be described below with reference to the drawings.

The figure is a circuit diagram of an embodiment of a starter protection device for a vehicle according to the present invention.

In the figure, 1 located at the center right of the figure is a manual key switch, 2 to 2 are starter relays, and excitation coil 2.
-1, a normally open contact 2-2, and a diode 2-3. 3 is a switching transistor, 4~
is an engagement switch and pull coil 4-
1, a holding coil 4-2, a movable iron core 4-3, a movable contact 4-4, and fixed contacts 4-5 and 4-6. 5 - a starter, which includes an armature 5-1 and a pinion gear 5- operated by the armature 5-1;
2 and a pinion shift lever 5-3. Reference numeral 6 is a ring gear provided on the engine side (not shown), 7 is a battery, 8 is a battery switch, 9 to 9 are generators, including a generator coil 9-1, a full-wave rectifier 9-2, a field coil 9-3, and a voltage regulator. Vessel 9
It consists of -4. 10 and 11 are operational amplifiers, _T1 and _T3 are reference terminals of the operational amplifiers, _T2 and _T4 are input terminals, _T5 and
T ₆ represents an output terminal, respectively. 12 is a transistor, 13 is a logic inverter (not), 14 to 41 are each a resistor including a thermistor 29, 42 to 47 are each a capacitor, 48 to 53 are each a diode, 54 to 56 are each a Zener diode, and N is a generator. represents the neutral point of

In the figure, considering the time when the vehicle is stopped, in this case battery voltage is applied to the voltage dividing resistors 20 and 21 via the resistor 25 by closing the battery switch 8, and the reference is determined by the voltage dividing ratio of each of the resistors. A voltage (for example, about 0.1V) is applied to the reference terminal T ₁ of the first operational amplifier 10 .
The output terminal _T5 of the operational amplifier 10 maintains a high level. Therefore, the logic NOT circuit 13 becomes low level and the transistor 1
2 is off, the high level output from the operational amplifier 10 is passed through the diode 49 and the resistor 15 to the switching transistor 3.
A base current is supplied to the switching transistor 3, and the switching transistor 3 is in a state where it can be turned on.

Now, when the manual key switch 1 is closed in order to start the engine (not shown), the switching transistor 3 is turned on because it is in a state where it can be turned on as described above, and the excitation coils 2 of the starter relays 2 to 2 are turned on.
A current flows through -1 to energize the coil and normally open contact 2.
-2 is closed. By closing the normally open contact 2-2, a base current flows through the switching transistor 3 via the resistor 14 to maintain the on state, and the pull coil 4-1 of the engagement switch 4 to the electric motor of the starter Current also flows through the child 5-1. Then, the movable iron core 4-3 is attracted by the current flowing through the pull coil 4-1, actuating the movable contact 4-4 and making the fixed contacts 4-5, 4-6
bridge. Thus, the armature 5-1 of the starter is energized by the current flowing from the battery 7 side through the fixed contacts 4-5 and 4-6 without passing through the circuit from the pull coil 4-1 side, and starts rotating. On the other hand, when the armature 5-1 of the starter starts rotating due to the current from the pull coil 4-1, the pinion gear 5-2 is brought into mesh with the ring gear 6 on the engine side by the operation of the pinion shift lever 5-3. Therefore, the above-mentioned fixed contact 4-
The armature 5-1 of the starter rotates at full power by the current from the 5 and 4-6 sides to drive the engine, and the engine is started.

Note that when the normally open contact 2-2 is closed by the operation of the starter relay 2~, the voltage of the battery 7 is applied to the input terminal _T2 of the first operational amplifier 10 via the contact 2-2. By the way,
At the same time, the battery voltage divided by each of resistors 26, 27, 28, and 29, that is, resistor 2
7 and 28 is applied to the reference terminal T ₁ of the first operational amplifier 10 and becomes, for example, about 0.9V. Even if applied to terminal T ₂ (shunted by diode 50, the voltage at terminal T ₂ is, for example, approximately 0.7V).
) first operational amplifier 10
The output of is at a high level, transistor 12 is off, and switching transistor 3 remains on as long as manual key switch 1 is closed. As the engine rotates under its own power, a voltage is generated in the generator coils 9-1 of the generators 9 to 9-1 directly connected to the engine, and at the same time, an alternating current voltage is induced at the neutral point N. This neutral point voltage is passed through a circuit consisting of capacitors 46, 47, resistors 39, 40, 41, etc., and the AC component from which the DC component is removed is applied to the input terminal of the second operational amplifier 11.
Applied to T ₄ . Therefore, the output terminal T ₆ of the second operational amplifier 11 has the DC voltage previously applied to the reference terminal T ₃ and the input terminal
A pulse voltage corresponding to the frequency of the AC voltage is generated by taking the difference from the AC voltage applied to T ₄ ,
It is differentiated by a differentiator circuit consisting of a capacitor 45 and a resistor 33. Then, the differentiated voltage is made into only a positive voltage by passing through a diode 53, and is further introduced into an integrating circuit consisting of a resistor 31 and a capacitor 44. Since the terminal voltage of the capacitor 44 corresponds to the pulse period introduced into the integrating circuit, that is, it starts increasing when the pulse repetition frequency exceeds a predetermined value, so that the engine speed does not reach the predetermined value. When the voltage is reached, the terminal voltage of the capacitor 44 starts to rise. Since the terminal voltage of the capacitor 44 is applied to the input terminal _T2 of the first operational amplifier 10, when the terminal voltage of the capacitor 44 reaches a predetermined value, the output of the first operational amplifier 10 becomes a low level. . That is, the engine's own rotation is detected by the first operational amplifier 10.

When the self-powered rotation of the engine exceeds a predetermined value, the output terminal of the first operational amplifier 10
T ₅ moves to a lower level as described above. At this time, as mentioned above _{, the potential of the reference terminal T 1 of the first operational amplifier 10 is about 0.9V, so the input terminal T 2 is} connected to the second operational amplifier 11 from the second operational amplifier 11 side. When a voltage of 0.9V or more is applied, the output terminal _T5 may go to a low level. As the output terminal _T5 of the first operational amplifier 10 goes low, the output of the logic NOT circuit 13 goes high, turning on the transistor 12 and diverting the base current of the switching transistor 3 to the side. The switching transistor 3 is turned off, thereby opening the contact 2-2 of the starter relay 2. Due to this opening of contact 2-2 of starter relay 2, the voltage applied to reference terminal _T1 of first operational amplifier 10 decreases from the above-mentioned approximately 0.9V to approximately 0.1V again, so that the voltage applied to input terminal _T2 decreases from approximately 0.9V to approximately 0.1V. The voltage applied from the second operational amplifier 11 side, etc., will not recover unless it drops below about 0.1V. That is, in this state,
Even if the operator continues to turn on the manual key switch 1, the switching transistor 3 will be forced to the OFF state and the starter will automatically recover. The switching transistor 3 is then maintained in the off state.

This means the following: That is, while the engine is rotating under its own power, the first operational amplifier 10 is always at a low level, and the switching transistor 3 is placed in an off state. Therefore, even if the manual key switch 1 is closed by mistake while the engine is normally rotating on its own, the starter relay 2 will not operate and the starter pinion gear 5-
2 will not collide with the ring gear 6 of the rotating engine and cause damage.

Note that even if the operator confirms that the engine is running on its own and opens the manual key switch 1 before that, the normally open contact 2-2 of the starter relay 2 will also become open and the holding coil 4-2 in the engagement switch 4 will open.
is released, and at the same time the movable contact 4-4 is released from the fixed contacts 4-5 and 4-6,
The pinion gear 5-2, which has been engaged with the ring gear 6 on the engine side, can be disengaged and returned to its original position. Therefore, the starter armature 5
-1 will then undergo inertia rotation and come to a stop.

Next, the operation of the starter during inertia rotation will be explained. Inertial rotation of the starter is a state in which the pinion gear 5-2 on the armature 5-1 side of the starter and the ring gear 6 on the engine side separate and return to their original positions after the engine rotates normally, or when the engine fails to start. With each gear having returned to its original position, the starter continues to rotate due to inertia. However, in any of the above states, the normally open contact 2 of the starter relay 2
-2 is open circuit and starter armature 5-1
rotates due to inertia and generates voltage. Therefore, this voltage is passed through the pull coil 4-1 to the first
is applied to the input terminal _T2 of the operational amplifier 10. This voltage is applied to the reference terminal T ₁
is higher than the reference voltage (for example, about 0.1V) given by the voltage-dividing resistance ratio. The output terminal _T5 of the first operational amplifier is at a low level, keeping the switching transistor 3 in the off state. In this case, since the contact 2-2 is turned off, the transistor 12 does not necessarily need to be turned on. Therefore, even if the manual key switch 1 is accidentally closed during the inertia rotation of the starter, the starter relay 2 will not operate, and the rotating pinion gear 5-2 will not collide with the ring gear 6 of the engine and be damaged.

Note that during inertia rotation, the voltage applied to the input terminal _T2 of the first operational amplifier 10 gradually decreases as the inertia rotation speed of the armature 5-1 of the starter decreases; Since a time constant circuit consisting of a resistor 23 and a capacitor 43 is connected to the terminal _T2 , the voltage will not drop below the reference voltage until the inertia rotation of the armature 5-1 of the starter is almost completely stopped. For this reason, the first
The output terminal _T5 of the operational amplifier 10 maintains a low level until the inertia rotation stops,
Therefore, switching transistor 3 remains off.

As explained above, according to the present invention, the engine speed is indirectly detected by the first operational amplifier that directly controls the switching transistor and the frequency of the AC voltage induced at the neutral point of the generator. Since the switching transistor is controlled by using a second operational amplifier and applying the output of the second operational amplifier to the input terminal of the first operational amplifier, The entire control circuit is miniaturized, the switching transistors are controlled more reliably, and the inertial jump phenomenon is completely prevented.

[Brief explanation of the drawing]

The figure shows an embodiment of a starter protection device for a vehicle according to the present invention. In the figure, 1 is a manual key switch, 2 to 2 are starter relays, 2-1 is an excitation coil, 2-2 is a normally open contact,
3 is a switching transistor, 4- is an engagement switch, 5- is a starter, 6 is a ring gear, 7 is a battery, 8 is a battery switch, 9- is a generator,
10 and 11 are first and second operational amplifiers, 12 is a transistor, and 13 is a logic NOT circuit.

Claims (1)

[Claims] 1 A manual key switch, a starter relay that is activated by battery voltage when the manual key switch is closed, an engagement switch that is activated by the battery voltage by the starter relay to start the engine, and a voltage that is applied through the engagement switch. A switching transistor for controlling the operation of the starter relay; and a switching transistor for controlling the operation of the starter relay when the manual key switch is turned on and the starter relay is activated. a first operational amplifier that controls the switching transistor, and a reference voltage of the first operational amplifier that supplies the terminal voltage of the starter during inertia rotation of the starter; a transistor that forcibly controls the switching transistor to be turned off by the output from the first operational amplifier; and a second operational amplifier to which the neutral point voltage of the generator is applied. a differential circuit and an integrating circuit connected to the output terminal of the second operational amplifier, and a circuit that supplies the output signal from the second operational amplifier to the input terminal of the first operational amplifier. and the output from the second operational amplifier is supplied to the reference terminal of the first operational amplifier at a level exceeding the reference voltage at that point in time. A starter protection device for a vehicle, characterized in that an operational amplifier controls the switching transistor to be forcibly turned off.