JP2001035345A - Circuit breaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker device capable of accurately detecting current passing through a conductor, surely cutting off a circuit in a short time for protecting electrical parts. SOLUTION: A pair of bus bars 11a, 19a and a thermit case 26 having conductivity and pinched by a pair of bus bars 11a, 19a form a loop-like current path. The upward current is flows from the first bus bar 11a to the thermit case 26, and the downward current is flowed from the thermit case 26 to the second bus bar 19a, and a first magnetic flux Φ1 is generated by the upward current, and a second magnetic flux Φ2 is generated by the downward current. A first magnetism/electricity converting element 37a and a second magnetism/electricity converting element 37b convert the first magnetic flux Φ1 and the second magnetic flux Φ2 into electrical signal, and the current is detected on the basis of this electrical signal. Current can be thereby detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker for interrupting an electric circuit in a short time, and more particularly to a circuit breaker for detecting a current flowing through a circuit with a magneto-electric conversion element with high accuracy, and operating the circuit based on the detected current value. The present invention relates to a circuit interrupting device for interrupting.

[0002]

2. Description of the Related Art In an electrical system provided in a vehicle, a load such as a power window causes some abnormality,
When an abnormality occurs in a wire harness formed by a plurality of electric wires connecting a battery and each load, a large current fuse inserted between the battery and the wire harness is blown, and the battery is disconnected. When,
2. Description of the Related Art A circuit breaker that cuts off a connection with a wire harness and thereby prevents each load, a wire harness, and the like from being burned is mounted on a vehicle.

As a conventional circuit breaker of this type, for example, a power supply breaker described in Japanese Patent Application Laid-Open No. 6-321027 is known.

As shown in FIG. 9, the power supply shut-off device described in Japanese Patent Application Laid-Open No. 6-321027 is intended to secure the safety of a vehicle by interrupting a current flowing from a battery when a power supply system fails. , A silicon-controlled rectifier 105 that causes an overcurrent to flow through the fusible link 102, and a current detection unit 104 that detects a current flowing through the fusible link 102.
And each part state monitoring unit 10 for monitoring the operation state of each part of the vehicle
7, a total current calculating unit 108 for calculating a total current based on each unit operating state of each unit state monitoring unit 107, and a current detecting unit 1
The control unit 109 is configured to compare the current value detected at 04 with the current value calculated by the total current calculation unit 108 and operate the silicon control rectifier 105 when it is determined that a power supply failure has occurred.

According to such a power cutoff device, the fusible link 102 cuts off the current flowing from the battery when an overcurrent flows, and the silicon control rectifier 105 generates an overcurrent in the fusible link 102. The current detector 104 detects a current flowing through the fusible link 102.

The component status monitoring unit 107 monitors the operating status of each component of the vehicle, the total current calculation unit 108 calculates the total current based on the operating status of each component of the component status monitoring unit 107, and the control unit 109 controls the current The current value detected by the detection unit 104 is compared with the current value calculated by the total current calculation unit 108, and when it is determined that the power supply has failed, the silicon control rectifier 105 is operated.

As described above, the total value of the current flowing from the battery and the current value actually used and used in the device is calculated, and the two current values are compared to determine that a failure has occurred. When the determination is made, the current flowing from the battery is cut off, so that the safety of the vehicle can be reliably ensured.

Further, the above-described power supply cutoff device is provided with a current detector such as a current detector 104. As a conventional current detector, for example, Japanese Unexamined Patent Publication No. Hei.
A current detector described in Japanese Patent Application Laid-Open No. 9-209 is known.

This current detector is, as shown in FIG.
A conductor 201 that forms a loop-shaped current path 201b by cutting or bending in the same plane to flow a current to be detected, and a magnetoelectric converter 202 that converts a magnetic flux generated by the current to be detected flowing through the conductor 201 into an electric signal; have.

According to such a current detector, the conductor 20
When a detected current flows through one current path 201b, a magnetic flux F penetrating through the center of the loop-shaped conductor path 201b is generated. This magnetic flux F is converted into an electric signal by the magnetoelectric conversion element 202, and an electric signal proportional to the detected current value is obtained, so that the detected current I can be detected.

[0011]

However, in the conventional current detector described in JP-A-5-223849, the conductor 201 is provided with a cut 201a or a bend, so that the strength of the conductor 201 is reduced. And the electrical resistance increases. Due to the increase in the electric resistance, there has been a problem that the current to be detected cannot be accurately detected.

The present invention can accurately detect a current flowing through a conductor, and can cut off a circuit in a short time and reliably based on the detected current value, thereby protecting an electric component. It is an object to provide a device.

[0013]

Means for Solving the Problems To solve the above problems, the present invention has the following arrangement. The invention according to claim 1 is a circuit breaker that supplies a current from a power supply to a load, and that cuts off a circuit from the power supply to the load when an abnormality occurs in a vehicle, comprising: a first connection terminal connected to the power supply; A loop-shaped current path is formed by a pair of connection terminals including a second connection terminal connected to the load side and a conductive member sandwiched between the pair of connection terminals, based on an input cutoff signal. A circuit breaker for interrupting a current flowing in the current path, and a magnetic flux generated by the current flowing in the loop-shaped current path, which is attached to the circuit breaker, is converted into an electric signal, and the current is detected based on the electric signal. Magneto-electric conversion unit, determines whether the current value detected by this magneto-electric conversion unit is equal to or greater than a predetermined threshold, and when the current value is equal to or greater than the threshold value, The shut-off signal Characterized in that it comprises a cut-off control unit for force.

According to the first aspect of the present invention, a pair of connection terminals and a conductive member sandwiched between the pair of connection terminals form a loop-shaped current path. A current flows in one direction to the member, and a current flows in the opposite direction from the conductive member to the other connection terminal.
Is generated, the magnetoelectric conversion unit converts the generated first magnetic flux and second magnetic flux into an electric signal, and detects a current based on the electric signal. For this reason, the magnetic flux is strengthened, and the cutout is not provided in the pair of connection terminals, so that the current can be detected accurately.

The cutoff control section determines whether the current value detected by the magnetoelectric conversion section has exceeded a predetermined threshold, and when the current value has exceeded the threshold value, A cutoff signal is output to the circuit breaker, and the circuit breaker cuts off the current flowing through the current path based on the input cutoff signal, so that the circuit can be cut off in a short time and surely to protect the electric components.

According to a second aspect of the present invention, there is provided an annular casing to which the magnetoelectric conversion unit is attached, and the casing is attached to the circuit breaker such that the loop-shaped current path passes through the inside of the annular casing. It is characterized by.

According to the second aspect of the present invention, the annular casing to which the magnetoelectric converter is attached is provided, and the casing is attached to the circuit breaker so that the loop-shaped current path passes through the inside of the annular. The position of the connection terminal and the magnetoelectric conversion element is accurately maintained,
The current detection accuracy can be improved.

According to a third aspect of the present invention, the first distance between the magnetoelectric converter and the first connection terminal is substantially equal to the second distance between the magnetoelectric converter and the second connection terminal. Preferably, the magnetoelectric conversion unit is attached to the housing.

According to the third aspect of the present invention, the first distance between the magnetoelectric conversion unit and the first connection terminal is substantially equal to the second distance between the magnetoelectric conversion unit and the second connection terminal. Since the magneto-electric conversion unit is attached to the housing, the first magnetic flux generated by the one-way current flowing through one connection terminal and the second magnetic field generated by the reverse current flowing through the other connection terminal have substantially the same value. Since the magnetic flux penetrates the element, the magnetic flux is strengthened approximately twice, so that the current can be accurately detected.

According to a fourth aspect of the present invention, the magnetoelectric conversion unit is a first type.
And the first magnetoelectric conversion element comprises a second magnetoelectric conversion element in which the magnetic flux collection direction is arranged in the opposite direction.
Further, the circuit breaker includes a calculation unit that calculates a difference value between a current value from the first magnetoelectric conversion element and a current value from the second magnetoelectric conversion element.

According to the fourth aspect of the present invention, the magnetic field collecting direction of the second magnetoelectric conversion element is arranged in the opposite direction with respect to the first magnetoelectric conversion element, and the arithmetic unit is configured to output the signal from the first magnetoelectric conversion element. Since the difference between the current value and the current value from the second magnetoelectric conversion element is calculated, even if there is a change in magnetic flux due to external noise or the like, the change in magnetic flux is canceled out by the subtraction processing by the arithmetic unit, and the external noise is reduced. It is possible to prevent the detection of a current abnormality due to the above.

According to a fifth aspect of the present invention, the circuit breaker includes a heating section in which the conductive member is filled with a heating agent, an ignition section that ignites the heating agent in response to the interruption signal, the ignition section and the heating section. And an elastic member that can be extended and retracted, and this elastic member is attached in a compressed state and is detachable from the outer case, and when attached to the outer case, is in proximity to or in contact with the heating unit. And an attachment / detachment member which is arranged and melted by the heat of the heating agent.

According to the fifth aspect of the present invention, the attaching / detaching member to which the elastic member is attached in a compressed state is arranged near or in contact with the heating unit when attached to the outer case. When the ignition portion is ignited by the cutoff signal, the heating agent generates heat, and the heat causes the detachable member to melt. Because the compressed elastic member expands and jumps up the heating section,
Since the electrical connection between the heating unit and the first connection terminal and the second connection terminal is cut off, the circuit can be cut off in a short time and reliably, and the electric component can be protected.

Further, since the detachable member is configured to be detachably attached to the outer case, the attaching and detaching work of the detachable member is simplified. Furthermore, since the elastic member is held by the detachable member,
No external force is applied to the joint between the first connection terminal and the second connection terminal and the heating unit.

According to a sixth aspect of the present invention, a side wall portion is formed at an end of the heating portion, and a tip of each of the first connection terminal and the second connection terminal and the side wall portion have a low melting point. It is characterized by being joined by materials.

According to the sixth aspect of the present invention, since the respective distal end portions and the side wall portions of the first connection terminal and the second connection terminal are joined by the low melting point material, the detachable member and the low melting point are generated by the heat generated by the heating agent. When the material is melted, the heating section jumps up, and the electrical connection between the first connection terminal and the second connection terminal is cut off. Therefore, it is possible to cut off the circuit in a short time and surely, thereby protecting the electric components. it can. Further, since no spring force is applied to the low-melting-point material that is the joint between the first connection terminal, the second connection terminal, and the heating unit, the reliability of the joint can be improved.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the circuit breaker of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view taken along the line AA of the circuit breaker according to the embodiment before the circuit breaker. FIG. 2 is a top view of the circuit breaker according to the embodiment.
FIG. 3 is an assembled perspective view of the circuit breaker of the embodiment.
FIG. 4 is a state diagram of the retainer before the circuit breaker of the embodiment is cut off. FIG. 5 is a state diagram of the retainer after the circuit breaker of the embodiment has been cut off. FIG. 6 is a diagram illustrating a path of a current flowing through the circuit breaker according to the embodiment. FIG. 7 is a diagram illustrating a magnetic flux generated by a current flowing through the circuit breaker according to the embodiment.

In the circuit breaker shown in FIG. 1, the first bus bar 11a and the second bus bar 19a having a long plate shape are used.
Has a substantially L shape and is made of, for example, copper or a copper alloy. The first bus bar 11a has a round hole portion 12 and is connected to a battery or the like (not shown). The long bus bar 19a having a plate shape has a round hole portion 20 and is connected to a load or the like (not shown). I have.

In FIG. 3, an extension 50 having a square groove 51 is formed on the cap 14a, and a wedge-shaped engaging portion 55 fitted into the groove 51 is formed on the resin case 14b. Is covered with a cap 14a. Cap 14a and resin case 1
4b constitutes an outer case and is made of a container made of an insulating material such as a resin (thermoplastic resin).

Opening 53 formed in resin case 14b
Accommodates a cylindrical thermite case 26, in which a heating agent 27 and an ignition portion 29 to which a lead wire 31 is connected are accommodated, and an upper lid 24 is placed over the heating agent. .

The thermite case 26 has good thermal conductivity and does not melt due to the heat generated by the heating agent 27, for example, brass, copper,
A copper alloy, stainless steel, or the like is preferably used. The thermite case 26 is formed by metal drawing or the like, and is formed of a cylinder or a rectangular parallelepiped.

The igniting section 29 has an igniting agent, and ignites the igniting agent by heat generated by a current flowing through the lead wire 31 in the event of an abnormality of the vehicle such as a collision of the vehicle to generate thermite reaction heat in the heating agent 27. Let it.

The first bus bar 11a and the second bus bar 19a have their bent portions inserted through the resin case 14b, and the bus bar tips 13a, 16a are soldered (for example, having a melting point of 200 ° C. to 300 ° C.). The first bus bar 11a and the second bus bar 19a are electrically connected to the left and right side walls of the thermite case 26 through the low melting metal 23 serving as a melting point material. Connectable. The low melting point metal 23 is made of, for example, at least one metal selected from Sn, Pb, Zn, Al and Cu.

The heating agent 27 is, for example, iron oxide (Fe
_This is a thermite agent composed of a powder of a metal oxide such as ₂ O ₃ ) and an aluminum powder, and generates a high heat by causing a thermite reaction by the heat generation of the lead wire 31. This thermite agent is enclosed in a thermite case 26, which is a metal container, as a measure against moisture. In addition, iron oxide (F
e ₂ O ₃ ), instead of chromium oxide (Cr ₂ O ₃ ),
Manganese oxide (MnO ₂ ) or the like may be used. Also,
As the heating agent 27, B, Sn, FeSi, Zr, Ti
And at least one metal powder selected from CuO, MnO ₂ , Pb ₃ O ₄ , PbO ₂ , Fe ₃ O ₄ and Fe ₂ O ₃ , Alumina, bentonite, talc and the like may be used as a mixture of at least one kind of additives.

A retainer 45 made of a resin member is disposed in the opening 53 of the resin case 14b and below the thermite case 26. The retainer 45 has a compression spring 39a attached in a compressed state and is detachable from the resin case 14b.
A detachable member which is arranged near or in contact with the thermite case 26 when attached to the base 4b and is melted by the heat of the heating agent 27.

This retainer 45 is, as shown in FIG.
A base portion 61, a cutout portion 63 formed in the base portion 61,
A retainer body 65 planted with respect to the notch 63 and the base 61, a pair of retainer locking portions 67 formed at the tip of the retainer body 65, and a projection for attaching the retainer 45 to the resin case 14 b. And a case mounting claw 69. The case mounting claws 69 formed on the retainer 45 are fitted into the resin case 14b.

A compression spring 39a wound around the retainer body 65 in a spiral shape is disposed outside the retainer body 65, and the distal end of the compression spring 39a is
7. That is, the compression spring 39a is sandwiched in the retainer 45 in a compressed state.

The circuit breaker 10 is constituted by the components described above.
Is composed.

Next, on the outer periphery of the resin case 14b, as shown in FIG. 2, a first magnetoelectric conversion element 37a and a second magnetoelectric conversion element 37b (in FIG. 1, the magnetoelectric conversion element 37 is used). Is mounted, and the housing 33 is held by projecting housing holding portions 35a and 35b formed on the resin case 14b. The first bus bar 11a, the second bus bar 19a, and the thermite case 26 form a substantially convex shape to form a loop-shaped current path, and the casing is formed such that the loop-shaped current path passes through the inside of the ring. The body 33 is attached to the resin case 14b.

Further, the first magnetoelectric conversion element 37a and the first
Between the bus bars 11a and the second magnetoelectric conversion element 37b
The first magnetoelectric conversion element 37a and the second magnetoelectric conversion element 37b are attached to the housing 33 so that the distance between the first busbar 19a and the second busbar 19a is substantially the same.

The first magnetoelectric conversion element 37a and the second magnetoelectric conversion element 37b constitute a magnetoelectric conversion section, convert a magnetic flux generated by a current flowing through a loop-shaped current path into an electric signal, and generate an electric signal based on the electric signal. To detect the current.

The control section 36 constitutes a shutoff control section,
It is determined whether or not the current value detected by the magneto-electric conversion element 37a and the second magneto-electric conversion element 37b is equal to or greater than a predetermined threshold value. 29 to output a cutoff signal.

Next, the operation of the circuit breaker of the embodiment configured as described above will be described with reference to the drawings.

First, the retainer 45 is attached to the resin case 14b. First, the pair of retainer locking portions 67 are bent inward, and the compression spring 39a is pushed into the retainer 45 to attach the compression spring 39a to the retainer 45.

After the compression spring 39a is assembled, the retainer 45 having the compression spring 39a is inserted into the opening 53 from the lower surface of the resin case 14b.
The retainer 45 is attached to the resin case 14b by fitting the case attachment claws 69 formed on the retainer 45 to the resin case 14b.

Next, a description will be given of a circuit breaking operation in a state where the retainer 45 is attached to the resin case 14b.

First, in the normal state, for example, as shown in FIG. 6, current is supplied from a battery (not shown) to the first bus bar 11a, the thermite case 26, and the second bus bar 19a (directions a, b, c, d). , E, f in that order), and a current is supplied to a load (not shown).

Then, when the current flowing through the first bus bar 11a is in the direction b, as shown in FIG. 7, the current in the direction b (upward current) is applied around the first bus bar 11a and in the counterclockwise direction. Generates a _first magnetic flux Φ ₁ .

When the current flowing through the second bus bar 19a is in the direction e, as shown in FIG. 7, the current in the direction e (downward current) is applied around the second bus bar 19a and clockwise. A second magnetic flux Φ ₂ is generated.

Then, the first magnetic flux Φ is applied to each of the first magnetoelectric transducer 37a and the second magnetoelectric transducer 37b.
₁ and the second magnetic flux Φ ₂ are penetrated. Since the current is a constant value, the first magnetic flux Φ ₁ and the second magnetic flux Φ ₂ are equal. For this reason, the magnetic flux is strengthened twice, and the detection accuracy of the first magnetoelectric conversion element 37a and the second magnetoelectric conversion element 37b is doubled.

Next, the first magnetoelectric conversion element 37a and the second
Each of the magneto-electric conversion elements 37b obtains an electric signal proportional to the magnetic flux, detects a current flowing through the bus bar, and
6 outputs a shut-off signal to the ignition unit 29 when the current value detected by the first magnetoelectric conversion element 37a and the second magnetoelectric conversion element 37b exceeds a threshold value.

Then, an electric current flows to the ignition portion 29 through the lead wire 31 by the cutoff signal, and the ignition portion 29 is ignited by the heat generated by the electric current. Generates heat.

Fe ₂ O ₃ + 2AL → AL ₂ O ₃ + 2Fe + 3
86.2 Kcal Thermite reaction heat heats the thermite case 26, and the low-melting metal 23 is heated and melted by the heat generated by the heating agent 27 and the heat of the thermite case 26. Also,
At the same time, a retainer locking portion 6 made of a resin or a metal such as solder in which the compression spring 39a is compression-fixed to the retainer 45.
7 is melted by the heat. Then, as shown in FIG. 5, since the compression spring 39a expands, the thermite case 26 jumps up in the direction of the cap 14a.

Therefore, the thermite case 26 and the first
The electrical connection between the first bus bar 11a and the second bus bar 19a is cut off. That is, the electric circuit of the vehicle is interrupted.

As described above, according to the circuit breaker of the embodiment, the first bus bar 11a and the second bus bar 19a provided on the circuit breaker having a substantially convex state and the thermite case 26 form a loop. , The currents flow in different directions in the pair of bus bars, and the magnetic flux is strengthened approximately twice, so that the currents can be detected accurately. In addition, since no cut or the like is provided in the pair of connection terminals, the strength of the pair of connection terminals does not decrease, and the current can be detected with high accuracy without increasing the electrical resistance.

The first magneto-electric conversion element 37a and the second
The ring-shaped housing 33 to which the magneto-electric conversion element 37b is attached is mounted over the resin case 14b, so that the position of the bus bar and the first and second magneto-electric conversion elements 37a and 37b is accurately maintained. This improves the detection accuracy and simplifies the mounting operation.

In addition, a shutoff signal is input, and the ignition of the ignition portion 29 causes a thermite reaction in the heating agent 27,
The compression spring 39a instantly jumps up because the low melting point metal 23 and the retainer locking portion 67 are melted by the heat of thermite reaction. For this reason, the electric circuit of the vehicle can be shut off in a short time and reliably, and the electric components can be protected.

The retainer locking portion 67 of the retainer 45
Is located inside the compression spring 39a, the retainer locking portion 67 tends to fall inward due to the reaction force of the compression spring 39a, and the thermite case 26 and the retainer 45
And the heat conduction from the thermite case 26 to the retainer 45 is improved, so that the retainer locking portion 67 can be efficiently melted.

Further, the retainer locking portion 67 is turned inward,
By simply pressing the compression spring 39a into the retainer 45, the compression spring 39a can be easily assembled to the retainer 45, and the retainer 45 can be easily mounted on the resin case 14b.

Further, if the case mounting claws 69 formed on the retainer 45 are tilted inward from the resin case 14b,
The retainer 45 can be easily detached from the resin case 14b. Therefore, the resin case 14b of the retainer 45
Can be easily attached and detached. Further, since the compression spring 39a is held by the retainer 45, the first bus bar 11a, the second bus bar 19a, and the thermite case 2
No external force is applied to the junction with the metal 6, that is, the low melting point metal 23. Therefore, the reliability of the joint can be improved.

The sub-assembly of the compression spring 39a and the retainer 45 is connected to the lower surface of the fuse, that is, the resin case 1
The insertion of the circuit breaker from the opening 53 of the circuit breaker 4b is facilitated. Further, if the retainer 45 and the thermite case 26 are replaced after the circuit is cut off, the resin case 14b can be reused as a fuse in the same state.

The cap 14a is attached to the resin case 14b.
Thermite case 2 when the circuit is interrupted
6 does not jump out of the cap 14a, thereby preventing burns and the like due to heat.

Further, the direction of magnetic flux collection of the second magnetoelectric conversion element 37b is arranged in a direction opposite to that of the first magnetoelectric conversion element 37a,
Further, as shown in FIG. 8, the arithmetic unit 38 calculates the current value from the first magnetoelectric conversion element 37a and the second magnetoelectric conversion element 37a.
The difference value from the current value from b may be calculated.

For example, let ΔΦ be a magnetic flux due to external noise, and let the magnetic flux penetrating the first magnetoelectric conversion element 37a be (+ Φ +
ΔΦ), and the magnetic flux passing through the second magnetoelectric conversion element 37b is
Assuming (−Φ + ΔΦ), the calculation unit 38 calculates the following equation (1) to obtain a magnetic flux Φ free from the influence of external noise, thereby detecting a current free from the influence of external noise. be able to.

{(+ Φ + ΔΦ) − (− Φ + ΔΦ)} * 1/2 = Φ (1) In the embodiment, the compression spring 39 a and the low melting point metal 23 are provided, and the retainer 45 and the low melting point metal 23 are provided. Was melted, the circuit was interrupted. For example, only the retainer 45 was provided without providing the low melting point metal 23, and the retainer 45 was provided.
The circuit may be cut off when the metal melts.

In the embodiment, the housing 33 is provided separately from the resin case 14b.
A first magnetoelectric conversion element 37a and a second magnetoelectric conversion element 37b may be mounted on the outer periphery of the housing 33, and the housing 33 may be shared with the cap 14a.

In the circuit breaker of the embodiment, the circuit breaker using the thermite case 26 has been exemplified.
The circuit breaker of the present invention is not limited to the circuit breaker of the embodiment, but may be another circuit breaker.

Further, in the embodiment, the first magnetoelectric conversion element 37a and the second magnetoelectric conversion element 37b are attached to the housing 33. For example, one magnetoelectric conversion element is attached to the housing 33.
Or three or more magneto-electric conversion elements may be attached to the housing 33. In addition, it goes without saying that various modifications can be made without departing from the technical idea of the present invention.

[0069]

According to the present invention, a loop-shaped current path is formed by a pair of connection terminals and a conductive member sandwiched between the pair of connection terminals. A current flows in one direction to the conductive member, and a current flows in the opposite direction from the conductive member to the other connection terminal.
A first magnetic flux due to a current in one direction and a second magnetic flux due to a current in the opposite direction are generated, and the magnetoelectric conversion unit converts the generated first magnetic flux and the second magnetic flux into an electric signal and converts the electric signal into an electric signal. The current is detected based on the current. For this reason, the magnetic flux is strengthened, and the cutout is not provided in the pair of connection terminals, so that the current can be detected accurately.

Further, the cutoff control section determines whether the current value detected by the magnetoelectric conversion section has exceeded a predetermined threshold value, and when the current value has exceeded the threshold value, A cutoff signal is output to the circuit breaker, and the circuit breaker cuts off the current flowing through the current path based on the input cutoff signal, so that the circuit can be cut off in a short time and surely to protect the electric components.

According to the second aspect of the present invention, the annular casing to which the magnetoelectric conversion unit is attached is provided, and the casing is attached to the circuit breaker so that the loop-shaped current path passes through the inside of the annular. The position of the connection terminal and the magnetoelectric conversion element is accurately maintained,
The current detection accuracy can be improved.

According to the third aspect of the present invention, the first distance between the magnetoelectric conversion unit and the first connection terminal is substantially equal to the second distance between the magnetoelectric conversion unit and the second connection terminal. Since the magneto-electric conversion unit is attached to the housing, the first magnetic flux generated by the one-way current flowing through one connection terminal and the second magnetic field generated by the reverse current flowing through the other connection terminal have substantially the same value. Since the magnetic flux penetrates the element, the magnetic flux is strengthened approximately twice, so that the current can be accurately detected.

According to the fourth aspect of the present invention, the direction of magnetic flux collection of the second magneto-electric conversion element is arranged in the opposite direction to the first magneto-electric conversion element, and the arithmetic unit is configured to output the signal from the first magneto-electric conversion element. Since the difference between the current value and the current value from the second magnetoelectric conversion element is calculated, even if there is a change in magnetic flux due to external noise or the like, the change in magnetic flux is canceled out by the subtraction processing by the arithmetic unit, and the external noise is reduced. It is possible to prevent the detection of a current abnormality due to the above.

According to the fifth aspect of the present invention, the attaching / detaching member to which the elastic member is attached in a compressed state is arranged near or in contact with the heating section when attached to the outer case. When the ignition portion is ignited by the cutoff signal, the heating agent generates heat, and the heat causes the detachable member to melt. Because the compressed elastic member expands and jumps up the heating section,
Since the electrical connection between the heating unit and the first connection terminal and the second connection terminal is cut off, the circuit can be cut off in a short time and reliably, and the electric component can be protected.

Further, since the detachable member is configured to be detachably attached to the outer case, the attaching and detaching operation of the detachable member is simplified. Furthermore, since the elastic member is held by the detachable member,
No external force is applied to the joint between the first connection terminal and the second connection terminal and the heating unit.

According to the sixth aspect of the present invention, since the distal end portion and the side wall portion of each of the first connection terminal and the second connection terminal are joined with the low melting point material, the detachable member and the low melting point are generated by the heat generated by the heating agent. When the material is melted, the heating section jumps up, and the electrical connection between the first connection terminal and the second connection terminal is cut off. Therefore, it is possible to cut off the circuit in a short time and surely, thereby protecting the electric components. it can. Further, since no spring force is applied to the low-melting-point material that is the joint between the first connection terminal, the second connection terminal, and the heating unit, the reliability of the joint can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along a line AA of a circuit breaker according to an embodiment before the circuit breaker.

FIG. 2 is a top view of the circuit breaker according to the embodiment.

FIG. 3 is an assembled perspective view of the circuit breaker of the embodiment.

FIG. 4 is a state diagram of a retainer before the circuit breaker of the embodiment is cut off.

FIG. 5 is a state diagram of the retainer after the circuit breaker of the embodiment has been cut off.

FIG. 6 is a diagram illustrating a path of a current flowing through the circuit breaker according to the embodiment;

FIG. 7 is a diagram showing a magnetic flux generated by a current flowing through the circuit breaker of the embodiment.

FIG. 8 is a diagram illustrating a noise removal circuit that removes external noise by using outputs of two magnetoelectric conversion elements provided in the circuit breaker according to the embodiment;

FIG. 9 is a diagram showing an example of a conventional power cutoff device.

FIG. 10 is a diagram illustrating an example of a conventional current detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Circuit breaker 11a 1st bus bar 13a, 16a Bus bar tip 14a Cap 14b Resin case 19a 2nd bus bar 23 Low melting point metal 24 Top lid 26 Thermit case 27 Heating agent 29 Ignition part 31 Lead wire 33 Housing 35a, 35b Housing Body holding unit 36 Control unit 37a First magnetoelectric conversion element 37b Second magnetoelectric conversion element 38 Operation unit 39a Compression spring 45 Retainer

Claims (6)

[Claims] 1. A circuit breaker for supplying a current from a power supply to a load and for interrupting a circuit from the power supply to the load when an abnormality occurs in a vehicle, comprising: a first connection terminal connected to the power supply side; A loop-shaped current path is formed by a pair of connection terminals including a second connection terminal connected to the side and a conductive member sandwiched between the pair of connection terminals, and the current is determined based on an input cutoff signal. A circuit breaker for interrupting a current flowing in a circuit path; and a magnetoelectric converter attached to the circuit breaker, for converting magnetic flux generated by the current flowing in the loop-shaped current path into an electric signal, and detecting the current based on the electric signal. Unit, and determines whether the current value detected by the magnetoelectric conversion unit is equal to or greater than a predetermined threshold value, and shuts off the circuit breaker when the current value is equal to or greater than the threshold value. Output signal A circuit breaker, comprising: 2. An annular housing to which said magnetoelectric conversion unit is attached is provided, and said housing is attached to said circuit breaker such that said loop-shaped current path passes through the inside of said annular. Item 2. The circuit breaker according to Item 1. 3. The magneto-optical device according to claim 1, wherein a first distance between the magneto-electric converter and the first connection terminal is substantially equal to a second distance between the magneto-electric converter and the second connection terminal. 3. The circuit breaker according to claim 2, wherein a converter is attached to the housing. 4. The magnetoelectric conversion section comprises a first magnetoelectric conversion element, and a second magnetoelectric conversion element in which the first magnetoelectric conversion element is arranged in the direction opposite to the magnetic flux collection direction. 4. The circuit breaker according to claim 3, further comprising a calculation unit that calculates a difference between a current value from the first magnetoelectric conversion element and a current value from the second magnetoelectric conversion element. 5. 5. The circuit breaker, wherein: a heating unit in which the conductive member is filled with a heating agent; an ignition unit that ignites the heating agent in response to the interruption signal; and an outer housing that houses the ignition unit and the heating unit. A case, a stretchable elastic member, and the elastic member is mounted in a compressed state and is detachable from the outer case, and is disposed near or in contact with the heating unit when mounted on the outer case. The circuit breaker according to any one of claims 1 to 4, further comprising: a detachable member that is melted by the heat of the heating agent. 6. A side wall portion is formed at an end portion of the heating section, and a tip portion of each of the first connection terminal and the second connection terminal and the side wall portion are joined by a low melting point material. The circuit breaker according to any one of claims 1 to 5, characterized in that: