JPH0392579A - Protective device for magnet type starter - Google Patents

Abstract

PURPOSE:To improve the reliability of operation by outputting the electric signal from an output circuit to a bypassing circuit bypassing a switching circuit when the counter electromotive force outputted from a motor is detected and a starter switch is closed during the inertial rotation while the excitation of the motor is stopped. CONSTITUTION:When a starter switch 4 is closed, a current is fed to a magnet switch 3 via a protective circuit 5, a plunger 33 is sucked by the synthetic magnetic force of a suction coil 31 and a holding coil 32 to close a main contact 37, and a motor 2 is rotatively driven. The protective circuit 5 is constituted of a switching circuit 6, a charge/discharge circuit 7 as an output circuit, and a bypassing circuit 8. The bypassing circuit 8 has a transistor 81 excited when the counter electromotive force generated by the inertial rotation while the excitation of the motor 2 is stopped is applied to a base 84, and the electric signal from the charge/discharge circuit 7 is outputted bypassing the switching circuit 6 when the starter switch 4 is closed during its excitation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protection device for a magnetic starter. [Prior Art] Conventionally, in a starter, if the starter switch is returned before the engine reaches a complete explosion, the energization to the multiple excitation coils of the magnetic switch is stopped, and as a result, the pinion gear separates from the ring gear and , the rotation of the pinion gear and armature gradually stops. When the driver notices that the engine is starting poorly and immediately turns on the starter switch again, the magnet switch's excitation coil is energized, pushing the pinion gear toward the ring gear. At this time, since the pinion gear rotates due to inertia, problems such as poor meshing between the pinion gear and ring gear, gear noise, and damage to the tooth surface of the ring gear occur. For this reason, the inventors of the present application have developed a starter (particularly Kaisho 62-1627
Publication No. 73) was proposed. [Problem to be Solved by the Invention] However, in the above-mentioned starter, if the inertial rotation of the armature becomes slow while the starter switch is turned on and held, the counter electromotive force of the armature also decreases. It becomes smaller. For this reason, there was a possibility that the relay would operate on the side that energized the excitation coil of the magnetic switch, and there was some concern about reliability. The present invention aims to provide a protection device for a magnetic starter that can improve reliability. [Means for Solving the Problems] The protection device for a magnetic starter of the present invention includes a motor that has a permanent magnet that creates a magnetic field and rotates a pinion gear when energized, and a motor that rotates the pinion gear when energized. engaging the ring gear and supplying electricity to the motor;
a magnetic switch that stops supplying electricity to the motor when energization is stopped; a starter switch that is manually opened and closed; and an output circuit that outputs an electrical signal for a predetermined time after closing the starter switch; a switching circuit that energizes the magnetic switch from inputting the electric signal output from the circuit until the starter switch is opened; and a detection circuit that detects a back electromotive force output by the motor during inert rotation when energization is stopped. and a detour circuit that detours the electrical signal output from the output circuit from the switching circuit when the starter switch is closed when the counter electromotive force is detected by the detection means. ．． [Operation] (When the starter switch is closed) Until the specified time elapses after the starter switch is closed,
An electrical signal is output from the output circuit to the switching circuit. The switching circuit energizes the magnetic switch when an electrical signal is input. As a result, the pinion gear engages with the engine's ring gear due to the magnetic switch. Also, since the motor is energized by the magnetic switch, the pinion gear rotates and starts the engine.
When the starter switch opens, the switching circuit stops energizing the magnetic switch, and
Stop supplying electricity to the motor. Then, the pinion gear separates from the ring gear.

Also, the rotation of the pinion gear and motor gradually stops. At this time, the motor generates a back electromotive force due to inertia rotation when power is stopped. (When the starter switch is closed again) If the motor is still rotating by inertia, the detection means detects the back electromotive force output by the motor. At this time, when the starter switch is closed again, the detour circuit detours the electrical signal output from the output circuit from the switching circuit. Then, the output circuit stops outputting the electric signal when a predetermined period of time elapses while the starter switch is held in the state where the starter switch is closed again. Therefore, even if the motor inertia rotates at a low speed and the back electromotive force becomes small and the detour circuit does not operate, input of electrical signals to the switching circuit is prevented. Therefore, since no electrical signal is input to the switching circuit, the magnetic switch is de-energized. This prevents the pinion gear from jumping into the ring gear during inertia rotation of the motor. Therefore, the present invention prevents the pinion gear from jumping into the ring gear again unless the starter switch is returned. [Effects of the invention] Poor meshing between the pinion gear and ring gear, gear noise,
Since defects such as damage to the ring gear tooth surface can be reliably prevented, it is possible to provide an extremely reliable protection device for magnetic starters. [Example] The protection device for a magnetic starter of the present invention will be explained based on an example shown in the figure. Figure 1 shows the electric circuit of a protection device for a magnetic starter employing the first embodiment of the present invention. A protection device 1 for a magnetic starter includes a motor 2, a magnetic switch 3, a starter switch 4, and a protection circuit 5. 10 is a vehicle power supply installed in the vehicle. The motor 2 is composed of a permanent magnet 21 that creates a magnetic field, a rotating armature 22, a brush 23 that flows current through the armature 22, and the like. The armature 22 is
The armature 22 itself rotates when energized, thereby driving a pinion gear (not shown) to rotate, and when the road train stops, the armature 22 itself stops rotating, thereby stopping the rotation of the pinion gear. Further, the armature 22 generates a back electromotive force (induced voltage) during inertia rotation when the current supply is stopped.

The magnetic switch 3 pushes out the pinion gear,
It functions to control the energization and de-energization of the armature 22. The magnetic switch 3 includes an attraction coil 31,
It consists of a holding coil 32, a plunger 33, a return spring (not shown), etc. The attraction coil 31 and the holding coil 32 are connected to the first terminal 34
, and has a second terminal 35 connected in series to both terminals and a third terminal 36 grounded. The first terminal 34 connects the attraction coil 31 and the holding coil 32 to the protection circuit 5 in parallel.
The second terminal 35 connects the attraction coil 31 and the holding coil 32 to the armature 22 in series. When electricity is supplied from the first terminal 34, current flows in parallel to the attraction coil 31 and the holding coil 32, so the attraction coil 31
The plunger 33 is attracted by the combined magnetic force of the holding coil 32 and the holding coil 32, and the main contact 37 is closed. When electricity is supplied from the second terminal 35, a current flows in series between the attraction coil 31 and the holding coil 32, and the mutual magnetic forces of the attraction coil 31 and holding coil 32 cancel each other out, causing the return spring to The force causes plunger 33 to return and main contact 37 to open. Furthermore, when the plunger 33 is attracted, the magnetic switch 3 drives a drive lever (not shown) to engage the pinion gear in the ring gear of the engine. 22 and the power source 10 to supply electricity to the armature 22. When the main contact 37 opens, the connection between the armature 22 and the power source 10 is cut off, and the armature 2 is connected to the power source 10.
Stop the electricity supply to 2. The starter switch 4 is
Ignition contact 41. and starter contact 42
has. The starter switch 4 has a starter contact 42
When the switch is closed (starter switch 4 is turned on), current flows in parallel to the attraction coil 31 and holding coil 32 via the protection circuit 5. Further, when the starter switch 4 opens the starter contact 42 (returns the starter switch 4), the starter switch 4 cuts off the connection with the attraction coil 31 and the holding coil 32 via the power supply 10 and the protection circuit 5. The protection circuit 5 includes a switching circuit 6, a charging/discharging circuit 7 as an output circuit, and a detour circuit 8. The switching circuit 6 includes a unidirectional three-terminal thyristor 61 . as a semiconductor switching element. and the thyristor 6
1 protection diode 62. Thyristor 61
has three terminals: an anode, a cathode, and a gate. The anode is connected to the starter contact 42 of the starter switch 4. The cathode is the suction coil 31
and is connected to the first terminal 34 of the holding coil 32. Gate 1 is connected to the charging/discharging circuit 7. When the gate of the thyristor 61 receives an electric signal through the diode 63, a current flows from the anode to the cathode.
At this time, the thyristor 61 connects the power source 10 and the attraction coil 3.
1 and holding coil 32 are connected in parallel. The charging/discharging circuit 1 includes a capacitor 71. It consists of resistors 72, 73 and a diode 74. The charging/discharging circuit 7 operates the thyristor 61 for a predetermined period of time after the starter contact 42 of the starter switch 4 closes until charging is completed.
Outputs an electrical signal (pulse signal) to the gate. The charge in the capacitor 71 is discharged over a predetermined period of time when the starter contact 42 of the starter switch 4 is opened. The detour circuit 8 is connected to an NPN transistor 81 and a resistor 82 for protection of the transistor 81. The transistor 81 has three terminals: a base 84 serving as a detection means, a collector, and an emitter. The base 84 is connected between the armature 22 and the main contact via a resistor 83. The collector is connected to a capacitor 71 via a resistor 73, and the emitter is grounded. This transistor 81 has a base 84 connected to the armature 2.
When a back electromotive force is detected from 2, a current flows from the collector to the emitter. Therefore, the detour circuit 8 is connected to the armature 2.
The pulse signal output from the charging/discharging circuit 7 is bypassed from the switching circuit 6 during the inertia rotation when the current supply is stopped in step 2. The operation of the magnetic starter protection device 1 of this embodiment will be explained based on the drawings. ■, When the starter switch is turned on and the starter contact 42 of the starter switch 4 is closed,
The thyristor 6 is connected to the capacitor 71 via the resistor 73 and the diode 63 for a predetermined time until charging is completed.
A pulse signal is output to gate 1. Thyristor 61
When a pulse signal is input to the gate, the attraction coil 31
Electricity is supplied to the first terminal 34 of the holding coil 32 and the holding coil 32.
Therefore, the plunger 33 is attracted by the combined magnetic force of the attraction coil 31 and the holding coil 32. Therefore, when the drive lever is driven, the pinion gear engages with the engine's ring gear. When the plunger 33 is further attracted, the main contact 37 of the magnetic switch 3 is closed. Main contact 37
is closed, armature 22 of motor 2 is connected to power supply 1.
Since it is connected to 0, it is energized. Therefore, when the armature 22 starts rotating relative to the permanent magnet 21, the pinion gear is rotationally driven by the armature 22 and drives the ring gear. Here, if the starter contact 42 of the starter switch 4 is closed before the engine reaches a complete explosion,
Attraction coil 31 and holding coil 32 by thyristor 61
The supply of electricity to the l-th terminal 34 is stopped. At this time, since the main contact 37 is still closed, the attraction coil 31 and the holding coil 32 are connected in series to the power supply 10 via the second terminal 35. Therefore, since electricity flows in series from the second terminal 35 to the attraction coil 31 and the holding coil 32, the mutual magnetic forces of the attraction coil 31 and the holding coil 32 cancel each other out, and the force of the return spring causes the plunger 33 to is returned and the main contact 31 is opened. Then, by opening the main contact 37, the power supply to the armature 22 is stopped, and the rotation of the pinion gear and the armature 22 is gradually stopped. At this time, the armature 22 generates a back electromotive force due to inertial rotation when the current is stopped. During inertia rotation of the armature 22, this back electromotive force is supplied to the attraction coil 31 and the holding coil 32 via the second terminal 35, and at the same time is supplied to the base 84 of the transistor 81 via the resistor 83. It will be done. Furthermore, when the starter contact 42 of the starter switch 4 is opened, the charge in the capacitor of the charging/discharging circuit 7 is transferred from the capacitor 71 to the resistor 72 to the ground to the diode 74 to the resistor 73.
→ Discharge through the path of capacitor 71 over a predetermined period of time. ■． When the starter switch is turned on again, the vehicle occupant notices that the engine is starting poorly and closes the starter switch 4 again while the armature 22 is rotating due to inertia. At this time, armature 22
Since the motor is inertly rotating, the base 84 of the transistor 81 detects the back electromotive force of the armature 22. Therefore, the transistor 81 attracts the pulse signal output from the charging/discharging circuit 7 and causes it to bypass the switching circuit 6. Then, while the starter contact 42 of the starter switch 4 is held in a closed state, the charging/discharging circuit 7 stops outputting the pulse signal when charging of the capacitor 71 is completed and a predetermined period of time has elapsed. Therefore, even if armature 2
The inertial rotation of No. 2 becomes a low-speed rotation, the back electromotive force becomes small, and even if the transistor 81 does not operate as the detour circuit 8, the pulse signal is prevented from being input to the gate of the thyristor 61.

Since the thyristor 61 has stopped supplying electricity to the l-th terminal 34, the attraction coil 31 and the holding coil 3
No electricity is supplied to both. Therefore, since the main contact 37 is held in an open state, the armature 22
The connection with the power supply 10 remains cut off, and the state in which the power supply to the armature 22 is stopped continues. Therefore, in this embodiment, even if the inertial rotation of the armature 22 becomes a low-speed rotation and the back electromotive force becomes small and the transistor 81 does not operate as the detour circuit 8, electricity is supplied to the attraction coil 31 and the holding coil 32. Not done. Therefore, the pinion gear does not jump into the ring gear. Therefore, it is possible to reliably prevent problems such as poor meshing between the pinion gear and ring gear, gear noise, and damage to the tooth surface of the ring gear, so that it is possible to provide a highly reliable protection device 1 for a magnetic starter. Furthermore, in this embodiment, the engine cannot be started unless the starter switch 4 is returned once, so the vehicle occupant can get into the habit of returning the starter switch 4 once when he or she fails to start the engine. Figure 2 shows an electric circuit of a protection device for a magnetic starter employing a second embodiment of the present invention. (The same functional components as in the first embodiment are given the same numbers.) In this actual tumor example, a relay circuit 9 consisting of a relay switch 91 and a relay coil 92 is added to the switching circuit 6 of the first embodiment as a switching circuit. There is. 51 is a diode. In this embodiment, the first terminal 34 is not directly controlled by the Cyrisk 61;
The first terminal 34 is controlled via the relay circuit 9. In the case of this embodiment, there is an effect that even a relatively large starter can be handled with a small capacity thyristor CIA=several A>. Furthermore, the voltage drop of the thyristor 61 can be ignored, and there is no need to increase the size of the attraction coil 31 and holding coil 32. [Modification] In this embodiment, the switching circuit is implemented using a thyristor, but the switching circuit may be configured using a plurality of transistors. In this embodiment, the detour circuit is made up of transistors, but the detour circuit may also be made up of thyristors.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram of a protection device for a magnetic starter employing a first example of the present invention, and Fig. 2 is an electric circuit diagram of a protection device for a magnetic starter employing a second embodiment of the present invention. It is. In the diagram 1... Protective device for magnetic starter 1f2... Motor 3
...Magnetic switch 4...Starter switch 5...Protection circuit 6...Switching circuit 1...
・Charge/discharge circuit (output circuit) 8...Detour circuit 9・
... Relay circuit (switching circuit) 21 ... Permanent magnet 84 ... Base (detection means)

Claims (1)

[Claims] 1) (a) A motor that has a permanent magnet that creates a magnetic field and rotates a pinion gear when energized, and (b) causes the pinion gear to engage a ring gear of an engine when energized. (c) a starter switch that is manually opened and closed;
) an output circuit that outputs an electrical signal for a predetermined period of time after the starter switch is closed; and (e) an output circuit that outputs an electrical signal for a predetermined period of time after the starter switch is closed; (f) a detection means for detecting a back electromotive force output by the motor during inertia rotation when electricity is stopped, and when the detection means detects the back electromotive force, the starter switch A protection device for a magnetic starter, comprising: a detour circuit that detours the electrical signal output from the output circuit from the switching circuit when the output circuit is closed.