JP2002115634A - Power circuit for starter motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of an electric device and a circuit due to a short-circuit without unnecessarily disconnecting a breaker. SOLUTION: This power circuit for starter motor comprises: a power supply 2 for the starter motor 4 for internal combustion engine; a main switch 1a; and a first relay switch 3 operating in conjunction with the main switch 1a and controlling current supply to the starter motor 4 for internal combustion engine. This power circuit for starter motor comprises: a breaker 6 arranged between the power supply 2 and the starter motor 4 for internal combustion engine; a second relay switch 7 carrying out bypass of a current with respect to the breaker 6; and a controller 8 carrying out control such that when the main switch 1a are reversed to be turned ON, the first relay switch 3 is turned ON, when the main switch 1a is reversed to be turned OFF, the first relay switch 3 is turned OFF, and when the first relay switch 3 is ON, the second relay switch 7 is turned ON.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for a starter motor for driving a starter motor for starting an internal combustion engine.

[0002]

2. Description of the Related Art An engine (internal combustion engine) mounted on an automobile, a construction machine, or the like includes a starting motor (starter motor).
Is provided. FIG. 9 is a diagram showing an example of a general power supply circuit for driving such a starter motor. Hereinafter, the power supply circuit will be described.

As shown in FIG. 9, when a driver operates a key switch 1 to turn on a starter switch 1a, a power supply 2 comprising two batteries 2a, 2a connected in series is provided.
Then, a current flows through the coil 3a of the relay switch 3, the coil 3a is excited, and the contact 3b of the relay switch 3 is turned on (the relay switch 3 is turned on). As a result, a closed circuit is formed, and current is supplied from the power supply 2 to the starter motor 4, so that the starter motor 4 operates to drive a crankshaft (not shown) to start an engine (this is called cranking).

The power source 2 is connected not only to the starter motor 4 but also to a plurality of electric devices (loads) not shown. Further, an engine-driven generator 5 is connected to the power supply 2.
(Battery 2a) is charged.

[0005]

By the way, in the above-mentioned general power supply circuit, as shown in FIG. 9, a breaker 9a is provided between the power supply 2 and the generator 5 for the purpose of protecting the circuit, and a power supply is provided. Fuse 9 is provided between each of 2 and an electric device (load) not shown. However, a large current (for example, several hundred amps) flows through the starter motor 4 during operation, but the general rated capacity of a circuit protection member such as a breaker or a fuse is smaller than this large current (for example, if a breaker, About 60 amps), and the circuit protection members are the battery 2a and the starter motor
Cannot be provided between For this reason, if a short circuit occurs in the line between the power supply 2 and the starter motor 4, each line between the power supply 2 and the fuse 9 (the line indicated by a thick line in FIG. 9), and the starter motor 4, a large short circuit occurs. Current may flow.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to prevent the deterioration of electric devices and circuits due to short circuits without unnecessarily disconnecting the breaker.
An object of the present invention is to provide a power supply circuit for a starter motor.

[0007]

According to a first aspect of the present invention, there is provided a power supply circuit for a starter motor, comprising: a power supply for a starter motor for an internal combustion engine; and a power supply between the power supply and the starter motor for the internal combustion engine. A starter motor including a main switch interposed in the power supply and a first relay switch for opening and closing the main switch to control the supply of current from the power supply to the starter motor for the internal combustion engine. In the power supply circuit, a breaker provided between the power supply and the starter motor for the internal combustion engine, a second relay switch that bypasses current from the power supply to the breaker, and the main switch is turned on. In this case, the first relay switch is turned on, and when the main switch is turned off, the first relay switch is turned off. It is characterized by being configured to include a controller for turning on the second relay switch when the relay switch is on.

In this case, when the main switch is turned on, the controller turns on the second relay switch and delays the first relay switch by a predetermined time after turning on the second relay switch. While the main switch is turned off, the first relay switch is turned off, and the second relay switch is turned off after a predetermined time from turning off the first relay switch. It is preferable to be constituted by a controller (claim 2).

It is preferable that the breaker is connected closer to the power supply on the positive electrode side than the power supply. Further, the power supply may be constituted by a plurality of batteries, and the breaker may be interposed between the batteries. In this case, the breaker, the second relay switch, and the controller are housed and integrated in the same casing, and the casing is provided with terminals for electrically connecting the plurality of batteries to each other. (Claim 5).

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Each embodiment shows an example in which the power supply circuit for a starter motor of the present invention is applied to a construction machine. (A) Description of First Embodiment First, a power supply circuit for a starter motor according to a first embodiment of the present invention will be described. 1 to 3 are diagrams showing a power supply circuit for a starter motor according to the present embodiment. Note that the same components as those described as the related art are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, a power supply circuit for a starter motor according to the present invention has a plurality (here, 2
) Batteries 2a connected in series;
Power supply 2 and starter motor (starter motor for internal combustion engine)
A starter switch (main switch) 1a interposed between the starter switch 4 and the key switch 1 to be turned on and off by operating the key switch 1;
It is provided with a first relay switch 3 interposed between the starter motor 4 and the starter switch 1a and opening and closing in conjunction with the starter switch 1a.

As shown in FIG. 1, not only a starter motor 4 but also a battery 2a
A plurality of electric devices (loads), not shown, are connected, an engine-driven generator 5 for charging the battery 2a is connected, and a fuse 9 is provided between each of these electric devices and the power supply 2. Each is interposed. Also,
Here, the battery 2a has a capacity of 12 V (volt).

The power supply circuit for a starter motor according to the present invention further includes a breaker 6 provided between the power supply 2 and the starter motor 4 and on the positive electrode side of the power supply 2 and close to the power supply 2.
And a second relay switch 7 provided in parallel with the breaker 6, and a controller 8 for controlling opening and closing operations of the first relay switch 3 and the second relay switch 7.

[0014] The controller 8, line L _G and the line L ₁
Disengaging with, and is for individually controlling the connection and disconnection of the line L _G and the line L _2. If the line L _G and the line L ₁ is connected, the first electromagnetic coil 3 of the relay switch 3
Since a current flows through a and the electromagnetic coil 3a is excited to turn on the contact 3b, the current is supplied from the power supply 2 to the starter motor 4. On the other hand, the line L _G
And when the line L ₂ is connected, the second relay switch 7 a current flows to the electromagnetic coil 7a of the contacts 7b and exciting the electromagnetic coil 7a is is turned on, current from the power supply 2 is, The circuit breaker 6 is bypassed and supplied to another device via a contact 7b having a lower electric resistance than the breaker 6.

During a short time (when the engine is started) during which the starter switch 1a is turned on and cranking is performed, a large current exceeding the capacity of the breaker 6 is supplied from the power source 2 to operate the starter motor 4. When the starter switch 1a is current being turned on from the line L ₀ to the controller 8 is supplied controller 8 turns on the second relay switch 7 as a cranking Thus, such a large current to the breaker 6 To bypass it.

On the other hand, when the starter switch 1a is turned off and cranking is not performed, that is, when the starter motor 4 is not operated (during normal operation of the engine), the power is supplied from the power source 2 if the state of the circuit is normal. current since less than the capacity of the breaker 6 is, as is not the once stopped during the cranking current supply starter switch 1a is turned off from the line L ₀ to the controller 8, the controller 8 and the second relay Turn off switch 7,
As a result, current is supplied to each load via the breaker 6.

In this way, when the starter motor 4 is operated (when the engine is started), the breaker 6 is not operated unnecessarily, and when the starter motor 4 is not operated (for example, when the key switch is in the accessory mode). When the overcurrent occurs due to, for example, a short circuit, the breaker 6 which is close to the power supply 2 on the positive electrode side is cut off.
This prevents an overcurrent from flowing to the line immediately downstream of the power supply circuit, that is, almost all the lines constituting the electric supply circuit.

As described above, when the first relay switch 3 is turned on and a large current is supplied from the power supply 2 to the starter motor 4, the second relay switch 7 is turned on and the large current is supplied to the breaker 6. When the first relay switch 3 is off and the tartar motor 4 is not operating, the first relay switch 3 is turned on to turn off the second relay switch 7 and pass the current through the breaker 6. At the same time, turn on the second relay switch 7,
It is preferable that the second relay switch 7 be turned off at the same time as the first relay switch 3 is turned off.

However, in order to ensure that the current bypasses the breaker 6 when the starter motor 4 operates,
The controller 8 is constituted by a timer-type controller, and specifically performs the following control. That is, when the starter switch 1a is current being turned to the line L ₀ is supplied, the timer type controller 8 detects this, turned with the second relay switch 7 is turned on immediately second relay switch 7 Predetermined time Δt
_{After one} elapse, that is, after the bypass path for the breaker 6 is secured, the first relay switch 3 is turned on to supply the current to the starter motor 4. Further, the timer type controller 8 includes a starter switch 1a.
Is turned off and the supply of current to the line L ₀ is stopped,
The timer-type controller 8 immediately turns off the first relay switch 3 and, after a predetermined time Δt _{2 has} elapsed since the first relay switch 3 was turned off, that is, after the current supply to the starter motor 4 is completed, 2 relay switch 7
Is turned off so that the current passes through the breaker 6.

In this embodiment, the on / off timing of the relay switches 3 and 7 is set as described above from the viewpoint of minimizing the contact capacity of the second relay switch 7 (contact 7b) through which a large current flows. ing. That is, when the contacts are opened and closed, the contacts are deteriorated or welded by an arc or the like. Therefore, the contact capacity of the switch is determined so that the performance can be exhibited even when the contacts are opened and closed. Therefore, by setting the on / off timing of the relay switches 3 and 7 as described above, the first relay switch 3
Is turned off and the current is not supplied to the second relay switch 7, that is, the second relay switch 7 is opened and closed in a state where no arc is generated, and a switch having a low contact capacity is used as the second relay switch 7. We are doing it.

Since the cranking time, that is, the time during which a large current is supplied to the second relay switch 7 is a relatively short time, the relay switch having a small contact capacity is also used as the second relay switch 7 from this point. It is possible to use Here, the timer-type controller 8 is a digital circuit in which a program for performing the above-described operation and the operation according to the following flowchart is installed.
M, RAM, and input interface circuit).

The power supply circuit for a starter motor according to the first embodiment of the present invention is configured as described above, and is controlled, for example, as shown in the flowchart of FIG. That is, first, the power starter switch 1a in accordance from 2 to supply state of the current to the line L ₀ is determined whether it is turned on (step A10), if the current from the power supply 2 to the line L ₀ if supplied Starter switch 1
Assuming that a is turned on, the second relay switch 7 is immediately turned on by the timer type controller 8 (step A20), and after a predetermined time Δt _{1 has} elapsed,
The first relay switch 3 is turned on (step A3)
0). Then, the flag F is set to 1 and the process returns (step A31).

Accordingly, as shown in FIG. 3, when the starter switch 1a is turned on by the driver's operation of the key switch 1, the second relay switch 7 is immediately turned on to form a bypass line for the breaker 6, and After a lapse of time Δt _{1 has} elapsed, the first relay switch 3 is turned on, and the supply of the current (cranking current) to the starter motor 4 is started.

On the other hand, in step A10 in FIG. 2, as if no current from the power source 2 to the line L ₀ is supplied starter switch 1a is turned off, Step A
After confirming that the flag F is set to 1 in step 11, the first relay switch 3 is immediately turned off by the timer-type controller 8 (step A40), and after a predetermined time Δt _{2 has} elapsed, the second relay The switch 7 is turned off (step A50). Then, the flag F is set to 0
(Step A51), and the process returns.

In step A11, the status switch
If there is no ON history of the switch 1a, the flag F is set to 1.
The starter switch 1a is turned off
Also, the processing after step A40 is not performed. Therefore,
As shown in FIG.
As soon as the switch 1a is turned off, the first relay switch
3 is turned off and the current to the starter motor 4 (cranking
Current is stopped, and a predetermined time elapses Δ
t _TwoThe second relay switch 7 is turned off.
This causes the current from the power supply 2 to flow through the breaker 6
Thus, it is supplied to each electric device mounted on the vehicle.

As a result, as shown in FIG. 3, the first relay switch 3 is turned on, and the starter motor 4
During cranking when a large current is supplied to
Since the second relay switch 7 is turned on and the power from the power supply 2 is supplied to each device by bypassing the breaker 6,
The breaker 6 does not operate unnecessarily, and
During a period in which the first relay switch 3 is turned off and the starter motor 4 is not operating, such as when the key switch 1 is in the accessory mode or during normal operation after cranking is completed, the second relay switch 7 is turned off. , Power supply 2
Is supplied to each device via the breaker 6, so that even if a short circuit occurs in the circuit and a short-circuit current occurs, the breaker 6 is cut off and the electric power including the circuit and the starter motor 4 is turned off. There is the advantage that the equipment is protected.

When the second relay switch 7 is turned off, the downstream side of the current from the breaker 6 is a protection section by the breaker 6, and most of the circuit is short-circuited because the breaker 6 is provided close to the positive electrode side of the power supply 2. There is an advantage that can be protected against. Also, the contact 7b of the second relay switch 7
As shown in FIG. 3, opening and closing are performed only during a period in which the first relay switch 3 is turned off and no current is supplied to the contact 7b, that is, a period during which there is no risk of deterioration or welding due to an arc or the like. Therefore, a low-capacity contact can be used as the contact 7b, and the contact 7b and thus the second relay switch 7 can be used.
In addition, there is an advantage that the size and cost of the starter motor power supply circuit can be reduced. (B) Description of Second Embodiment Next, a power supply circuit for a starter motor according to a second embodiment of the present invention will be described. 4 to 7 are diagrams showing a power supply circuit for a starter motor according to the present embodiment. Note that FIG. 3 used in the description of the first embodiment is also used and described. In addition, the same components as those described as the related art or the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 4, the starter motor power supply circuit of the second embodiment differs from the starter motor power supply circuit of the first embodiment in that
The second relay switch 7 and the timer-type controller 8
As shown in FIGS. 5A and 5B, they are housed in a casing 11 and are integrally configured as a circuit protection device 10. Note that a reset switch 6a for returning the disconnected breaker 6 to the connected state is provided outside the casing 11.

Further, in the first embodiment shown in FIG. 1 and FIG.
In the prior art shown, the batteries 2a, 2a are shown in FIG.
As shown in FIG.
In the embodiment, as shown in FIG.
It also functions as battery connection means, and connects the batteries 2a, 2a.
Has continued. Specifically, the circuit protection device 10 includes a clamp.
Terminal B₁, B_TwoAnd the circuit protection device 10
These clamp terminals B ₁, B_TwoTerminal of the battery 2a
Circuit protection device having a breaker 6 etc.
10 is interposed between the batteries 2a.

The circuit protection device 10 is configured to operate at 12 V (volts), and operates at the midpoint of the battery as a virtual ground. That is, as described above, each of the batteries 2a
(Volts), a voltage of 12 V is applied to the circuit protection device 10 on the current upstream side, and a voltage of 24 V is applied on the circuit downstream side. Therefore, a voltage of 12 V is applied to the circuit protection device 10 relative to the midpoint of the battery, and
The rated circuit protection device 10 operates as a virtual ground at the midpoint of the battery.

Further, as shown in FIG.
0, the connecting portion B ₄ is provided between the connecting part B ₃ and the line L ₁ side of the line L ₀ side. The circuit protection device 10 is provided with a connector 12 as shown in FIGS. 5A and 7, and the connection portions B ₃ and B ₄ are both connected to the connector 12.
It is provided for Of course, each connection part B ₃ , B ₄
The connector is not limited to the connector shown in FIG. 7A and shown in FIG. 7, and other general connection types can be applied. For example, the connector may be constituted by a screw terminal.

As described above, the power supply circuit for a starter motor according to the second embodiment of the present invention is configured as described above, and operates as follows when the engine is started. That is, as shown in FIG. 3, the starter switch 1a
When There is turned on, immediately the second relay switch 7 is a bypass line is formed for turned-on by the breaker 6, after the predetermined time Delta] t ₁ elapses, the supply of the first current of the relay switch 3 is turned to the starter motor 4 Be started. When the cranking is completed and the starter switch 1a is turned off, the first relay switch 3 is immediately turned off to stop the supply of current to the starter motor 4, and the predetermined time Δ
After elapse of t ₂ , the second relay switch 7 is turned off, and the current from the power supply 2 is supplied to each vehicle-mounted device via the breaker 6.

Therefore, the power supply circuit for the starter motor according to the second embodiment of the present invention has the same advantages as the power supply circuit for the starter motor according to the first embodiment. In addition, the breaker 6, the second relay switch 7, the timer type controller 8, and the like are integrally formed as a circuit protection device 10, which is different from the conventional power supply circuit for a starter motor.
There is an advantage that the power supply circuit for the starter motor can be easily configured simply by connecting the battery 2a by the circuit protection device 10 instead of the cable. (C) Others The power supply circuit for a starter motor of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention.

For example, in each of the above-described embodiments, when the starter switch 1a is turned on, the first relay switch 7 is turned on to form a bypass line for the breaker 6, and after a lapse of a predetermined time Δt1, the _first switch is turned on. Relay switch 3
To start supplying current to the starter motor 4,
When the starter switch 1a is turned off, the second relay switch 7 is turned off after a lapse of a predetermined time Δt ₂ since the first relay switch 3 is turned off and current supply to the starter motor 4 is stopped. The current from the power supply 2
The information is supplied to each device mounted on the vehicle via the. However, any configuration may be used as long as the second relay switch is turned on when the first relay switch 3 is turned on. That is, the first
While the relay switch 3 is on and a large current is being supplied to the starter motor, the second relay switch 3 only needs to be turned on to form a bypass line for the breaker 6.
Therefore, for example, immediately after the second relay switch 7 is turned on, the first relay switch 3 is turned on, and after the first relay switch 3 is turned off, the second relay switch 7 is immediately turned on.
May be turned off.

In this case, the controller 8 does not need to be of a timer type as in the above-described embodiment, but may be a digital circuit (a desired circuit in this circuit) in which a program for performing the above-described operation is installed. CPU and RO
M, RAM, and input interface circuit). Further, the controller 8 may be configured by a hardware circuit such as a logic circuit combining a logical operation element and a delay circuit, or an analog circuit using a time constant, as long as the controller 8 performs the above operation.

In each of the above embodiments, FIG.
As shown in FIG. 2, a second relay switch 7 having an electric resistance sufficiently lower than that of the breaker 6 is provided in parallel with the breaker 6, whereby the second relay switch 7 is provided.
Is turned on, the current is passed through the second relay switch 7 to bypass the breaker 6. The starter motor power supply circuit of the present invention is not limited to the configuration shown in FIG. 8A, as long as it allows current to bypass the breaker 6 during cranking. The configuration shown in FIG.

That is, the second relay switch 17 having the switch 17c for selectively opening and closing the two contacts 17a and 17b is provided on the current upstream side of the breaker 6. The second relay switch 17 is connected to the contact 1 by biasing means (not shown).
When the current is supplied to the electromagnetic coil 17d, the switch 17c is turned on to the contact 17a side, and when the current is supplied to the electromagnetic coil 17d, the electromagnetic coil 17d is excited. Then, the second relay switch 17 is turned on to the electromagnetic coil 17d, that is, the contact 17b side.

During non-cranking, no current is supplied to the electromagnetic coil 17d under the control of the controller 8, so that the switch 17c is turned on to the contact 17a side, and the current from the battery 2 passes through the breaker 6 Supplied to the load. Meanwhile, during the cranking, the current is supplied to the electromagnetic coil 17d via the line L ₂ from the controller 8, the switch 17c is turned to the contact 17b side.
As shown, the contact 17b is electrically connected to the downstream side of the breaker 6, so that the current from the power supply 2 bypasses the breaker 6 at this time.

Specifically, when such a second relay switch 17 is used, the above-described first embodiment will be described with reference to FIG.
It is configured as shown in FIG.
The configuration is as shown in FIG. Also,
In each of the above-described embodiments, an example in which the starter motor power supply circuit of the present invention is applied to an engine for a construction machine as an internal combustion engine has been described. However, the starter motor power supply circuit of the present invention is a stationary motor mounted on an automobile. It can be applied to various internal combustion engines such as a type.

[0040]

As described above in detail, according to the power supply circuit for a starter motor of the present invention, when the main switch is turned on, the first relay switch is turned on by the controller. Then, the supply of current from the power supply to the starter motor is started, and when the main switch is turned off, the first
The relay switch is turned off and the supply of current to the starter motor is stopped. When the first relay switch is on and a large current is being supplied to the starter motor, such as during cranking at the start of the internal combustion engine, the controller turns on the second relay switch to bypass the current to the breaker. As a result, a large current to the starter motor bypasses the breaker, thereby preventing the breaker from being unnecessarily disconnected.

When the first relay switch is off and current is not supplied to the starter motor for the internal combustion engine, as in the normal operation of the internal combustion engine after the completion of cranking, the second relay switch is turned off. Since electric current is supplied to the electric device via the breaker, when a large current flows due to a short circuit, the breaker is cut off, and deterioration of the circuit and each electric device is prevented.

Accordingly, there is an advantage that deterioration of a circuit or electric equipment due to a short circuit can be prevented without unnecessarily disconnecting the breaker. In addition, when the main switch is turned on, the controller turns on the second relay switch and turns on the first relay switch by delaying a predetermined time after turning on the second relay switch.
When the main switch is turned off, the second relay switch is turned off by turning off the first relay switch and turning off the second relay switch by a predetermined time after turning off the first relay switch. The on / off of the relay switch is performed when the first relay switch is off and no current is supplied to the second relay switch. That is, since the second relay switch is turned on and off in a state where there is no risk of deterioration due to an arc or the like, there is an advantage that a switch having a low contact capacity can be used as the second relay switch.

Further, by connecting the breaker closer to the power supply on the positive electrode side than the power supply, all lines constituting an electric device and a circuit, such as a starter motor for an internal combustion engine, supply current through the breaker. Since it is supplied, there is an advantage that deterioration of a circuit or an electric device at the time of short circuit can be reliably prevented (claim 3). The power supply is composed of a plurality of batteries, and the breaker is interposed between these batteries, so that the deterioration of the circuit and the electric equipment at the time of short circuit can be ensured as in the case of the starter motor power supply circuit according to the third aspect. There is an advantage that it can be prevented (claim 4).

In this case, the breaker, the second relay switch, and the controller are housed and integrated in the same casing, and a terminal for connecting the battery is provided in the casing. There is an advantage that the power supply circuit for the starter motor can be easily configured (claim 5).

[Brief description of the drawings]

FIG. 1 is a schematic electric circuit diagram showing a configuration of a power supply circuit for a starter motor as a first embodiment of the present invention.

FIG. 2 is a schematic flowchart for explaining control by a starter motor power supply circuit according to the first embodiment of the present invention.

FIG. 3 is a schematic time chart for explaining the operation of the power supply circuit for a starter motor according to the first embodiment of the present invention.

FIG. 4 is a schematic electric circuit diagram showing a configuration of a power supply circuit for a starter motor according to a second embodiment of the present invention.

FIG. 5 is a circuit protection device (battery connection means) according to a starter motor power supply circuit according to a second embodiment of the present invention.
(A) is a schematic plan view,
(B) is a schematic side view.

FIG. 6 is a schematic perspective view showing a battery connection structure in a conventional starter motor power supply circuit.

FIG. 7 is a circuit protection device (battery connection means) according to a starter motor power supply circuit according to a second embodiment of the present invention.
1 is a schematic perspective view showing a battery connection structure according to the first embodiment.

FIGS. 8A to 8D are schematic diagrams for explaining a main configuration of a modified example of the power supply circuit for a starter motor according to the present invention.

FIG. 9 is a schematic electric circuit diagram showing a configuration of a conventional starter motor power supply circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Key switch 1a Starter switch (main switch) 2 Power supply 2a Battery 3 First relay switch 3a, 7a, 17d Electromagnetic coil 3b, 7b, 17a, 17b Contact 4 Starter motor 5 Generator 6 Breaker 6a Reset switch 7, 17 Second Relay switch 8 Timer type controller 9 Fuse 10 Circuit protection device (battery connection means) 10a Clamp terminal 11 Casing 12 Connector

Claims (5)

[Claims] 1. A power supply for a starter motor for an internal combustion engine, a main switch interposed between the power supply and the starter motor for the internal combustion engine, and an opening / closing operation performed in conjunction with opening / closing of the main switch. In a starter motor power supply circuit including a first relay switch for controlling supply of current from the power supply to the internal combustion engine starter motor, a breaker provided between the power supply and the internal combustion engine starter motor A second relay switch for bypassing the current from the power supply to the breaker; and when the main switch is turned on, the first relay switch is turned on and the main switch is turned off. When the first relay switch is turned on, the first relay switch is turned off, and when the first relay switch is turned on, the second relay switch is turned on. A power supply circuit for a starter motor, comprising a roller and a starter motor. 2. The controller, when the main switch is turned on, turns on the second relay switch and delays the first relay switch by a predetermined time after turning on the second relay switch. When the main switch is turned off while the main switch is turned off, the first relay switch is turned off and the first relay switch is turned off.
2. The power supply circuit for a starter motor according to claim 1, further comprising a timer-type controller that turns off the second relay switch by delaying a predetermined time after turning off the relay switch. 3. The power supply circuit for a starter motor according to claim 1, wherein said breaker is connected closer to said power supply on a positive electrode side than said power supply. 4. The power supply circuit for a starter motor according to claim 1, wherein said power supply is constituted by a plurality of batteries, and said breaker is interposed between said batteries. 5. The circuit breaker, the second relay switch, and the controller are housed and integrated in the same casing, and the casing has terminals for electrically connecting the batteries. The power supply circuit for a starter motor according to claim 4, wherein the power supply circuit is provided.