Current sensor, shut-off device, and vehicle

Abstract

This current sensor (4) comprises a first yoke (401), a second yoke (402), and a coil (41). The first yoke (401) has an inner surface (4013) that faces a wiring member. The second yoke (402) moves toward the first yoke (401) due to a magnetic field (H1) generated by a current (Ib) flowing through the wiring member. The coil (41) is provided to the first yoke (401) or the second yoke (402).

Description

Current sensor, circuit breaker, and vehicle

[0001] The present disclosure relates generally to a current sensor, a circuit breaker, and a vehicle, and more particularly to a current sensor including a coil, a circuit breaker including a current sensor, and a vehicle including a circuit breaker.

[0002] Patent Document 1 discloses an on-board circuit breaker that includes a first conductive path, a second conductive path, a first current detector, a second current detector, a pyrotechnic circuit breaker, and a circuit breaker control unit.

[0003] The first conductive path connects the first input terminal and the first output terminal. DC power of a first polarity is supplied to the first input terminal. The second conductive path connects the second input terminal and the second output terminal. DC power of a second polarity opposite to the first polarity is supplied to the second input terminal. The first current detector can detect a current flowing in the first conductive path or the second conductive path. The second current detector can detect a current flowing in the first conductive path or the second conductive path. The pyrotechnic circuit breaker is capable of operating to irreversibly interrupt the first conductive path. The interruption control unit is capable of controlling the interruption operation of the pyrotechnic circuit breaker.

[0004] The tripping control unit is capable of receiving a first detection signal and a second detection signal transmitted from the first current detector and the second current detector in response to the detected currents, and causes the pyrotechnic circuit breaker to perform a tripping operation when both the first current value obtained based on the first detection signal and the second current value obtained based on the second detection signal exceed an overcurrent threshold.

[0005] Japanese Patent Application Laid-Open No. 2022-189212

[0006] In a current sensor used in a circuit breaker such as the on-board circuit breaker of Patent Document 1, there are cases where it is desired to improve the reliability of overcurrent detection.

[0007] A current sensor according to one aspect of the present disclosure includes a first yoke, a second yoke, and a coil. The first yoke has an inner surface facing a wiring member. The second yoke moves toward the first yoke due to a magnetic field generated by a current flowing through the wiring member. The coil is provided on the first yoke or the second yoke.

[0008] A circuit breaker according to one aspect of the present disclosure includes the current sensor and a circuit breaker unit. The circuit breaker unit is supplied with power generated by the coil. The circuit breaker unit has an igniter and a projectile. The igniter includes explosives and is configured to be able to ignite the explosives with the power generated by the coil. The projectile moves in response to the ignition of the explosives.

[0009] A vehicle according to one aspect of the present disclosure includes the circuit breaker, a battery, the wiring member, a motor, and a control unit. The motor is electrically connected to the battery via the wiring member. The control unit controls the supply of the current through the wiring member. In the vehicle, when an overcurrent flows between the battery and the motor, the explosive is ignited by the electric power generated by the coil. The projectile is configured to be projected and move toward the wiring member in response to the ignition of the explosive, thereby interrupting the electrical connection between the battery and the motor.

[0010] The present disclosure has the advantage of making it possible to improve the reliability of overcurrent detection.

[0011] FIG. 1 is a block diagram of an interrupter according to an embodiment. FIG. 2 is a diagram illustrating a circuit configuration of the interrupter. FIG. 3 is a perspective view of a detection unit provided in the interrupter. FIG. 4 is a partially cutaway front view of a main portion of the detection unit. FIG. 5 is a graph illustrating an example of a change in current over time flowing through a wiring member of the interrupter. FIG. 6 is a diagram illustrating an outline of a current sensor provided in the interrupter at time t11 in FIG. 5. FIG. 7 is a graph illustrating an example of a change in current over time flowing through a wiring member of the interrupter. FIG. 8 is a diagram illustrating an outline of the current sensor at time t21 in FIG. 7. FIG. 9 is a diagram illustrating an outline of the current sensor at time t22 in FIG. 7. FIG. 10 is a graph illustrating an example of a change in current over time flowing through a wiring member of the interrupter. FIG. 11 is a diagram illustrating an outline of the current sensor at time t31 in FIG. 10. FIG. 12 is a diagram illustrating an outline of the current sensor at time t32 in FIG. 10. Fig. 13 is a cross-sectional view of a breaking unit provided in the breaking device of the same. Fig. 14 is a schematic configuration diagram of a vehicle provided with the breaking device of the same. Fig. 15 is a partially cutaway front view of a main part of a current sensor of Modified Example 1. Fig. 16 is a partially cutaway front view of a main part of a current sensor of Modified Example 2. Fig. 17 is a partially cutaway front view of a main part of the current sensor of the same. Fig. 18 is a partially cutaway front view of a main part of a current sensor of another example of Modified Example 2. Fig. 19 is a front view of a main part of a current sensor of Modified Example 3. Fig. 20 is a diagram showing a circuit configuration of a breaking device of Modified Example 4. Fig. 21A is a diagram showing a circuit configuration of a first switching element provided in the breaking device of Modified Example 5. Fig. 21B is a diagram showing a circuit configuration of a second switching element provided in the breaking device of the same.

[0012] Hereinafter, a current sensor, a circuit breaker, and a vehicle according to embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the following embodiments are merely a portion of various embodiments of the present disclosure. The following embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, the drawings described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0013] (1) Embodiment (1.1) Breaker Device A breaker device 200 of this embodiment will be described with reference to FIGS. 1 to 13. FIG.

[0014] The interrupter 200 is mounted on an object. The object is a device having an electric circuit through which current supplied from a power source passes. The interrupter 200 is activated, for example, when an abnormality occurs in an electric circuit or system within the object, to interrupt the electric circuit, thereby preventing damage from the abnormality from becoming greater.

[0015] The object on which the cutoff device 200 is mounted is, for example, a vehicle 6 (see FIG. 14 ). The vehicle 6 has an electric circuit 60 for driving the vehicle 6. The electric circuit 60 is configured by connecting a motor 62, a battery 61 (e.g., a lithium-ion battery) for driving the motor, and circuit components including a switch via wiring members 9. The cutoff device 200 cuts off the electrical connection between the motor 62 and the battery 61 by cutting off the electric circuit 60 in the event of an emergency such as an abnormality or an accident of the vehicle 6, for example. Note that the object may be something other than the vehicle 6, and examples thereof include, but are not limited to, a home appliance and a solar power generation system.

[0016] 1 , the interrupting device 200 includes a detection unit 1 and an interrupting unit 2 electrically connected to the detection unit 1. In the present disclosure, "the first member and the second member are electrically connected" means that the first member and the second member are connected directly or via a third member so that electricity can flow from the first member to the second member (and / or from the second member to the first member).

[0017] (1.2) Detection Unit As shown in Figures 1 and 2, the detection unit 1 includes a current sensor 4 and a filter circuit 5. As shown in Figures 3 and 4, the detection unit 1 further includes a connector 17, a circuit board 18, and a housing 19.

[0018] (1.2.1) Current Sensor The current sensor 4 of this embodiment is a sensor that detects a current Ib flowing through the wiring member 9. The wiring member 9 includes, for example, a bus bar 90. The bus bar 90 is a conductor for passing a large current, and is, for example, a plate- or rod-shaped member made of a metal such as copper.

[0019] The current sensor 4 of this embodiment is a sensor for detecting, in particular, the flow of an overcurrent through the wiring member 9 (bus bar 90). When an overcurrent flows through the wiring member 9 (bus bar 90), the current sensor 4 outputs a signal to the outside (for example, the filter circuit 5). An overcurrent is a current that exceeds the current allowed to flow through the wiring member 9. In the present disclosure, the overcurrent includes a current that flows through the wiring member 9 continuously for a predetermined period of time or longer and exceeds the rated current of the wiring member 9. In addition, in the present disclosure, the overcurrent also includes a current (for example, a short-circuit current) whose magnitude momentarily becomes larger than the rated current of the wiring member 9.

[0020] 4, the current sensor 4 includes a first yoke 401, a second yoke 402, and a coil 41. The current sensor 4 also includes a resin member 49.

[0021] The first yoke 401 is made of a magnetic material and has an inner surface 4013 that faces the wiring member 9 (bus bar 90).

[0022] The first yoke 401 is formed in a U-shape. The first yoke 401 is disposed so as to surround the wiring member 9 (bus bar 90) on three sides. The first yoke 401 is fixed in position within the housing 19. The first yoke 401 has a first end 4011 and a second end 4012 at both ends thereof.

[0023] More specifically, the first yoke 401 has a rectangular plate-shaped first portion 403, and rectangular plate-shaped second and third portions 404 and 405 that protrude from both ends of the first portion 403 so as to intersect (e.g., perpendicular to) the first portion 403. The protruding end of the second portion 404 is a first end 4011 of the first yoke 401, and the protruding end of the third portion 405 is a second end 4012 of the first yoke 401. For convenience, the sides on which the first portion 403, the second portion 404, and the third portion 405 are located will also be referred to as the "top," "left," and "right," respectively.

[0024] 4, the resin member 49 is located in an area surrounded by the U-shaped first yoke 401. The resin member 49 is, for example, a part of the housing 19. For example, the first yoke 401 may be fixed to the resin member 49. A through-hole 490 is formed in the resin member 49, penetrating it in the front-rear direction (the normal direction of an imaginary plane including the first portion 403 to the third portion 405).

[0025] The second yoke 402 is made of a magnetic material. In this embodiment, the magnetic material forming the second yoke 402 is the same as the magnetic material forming the first yoke 401, but may be different.

[0026] The second yoke 402 has a plate shape, for example, a rectangular plate shape.

[0027] The second yoke 402 is disposed below the first yoke 401. The second yoke 402 is disposed to face the first end 4011 and the second end 4012 of the first yoke 401. More specifically, the first end 4021 of the second yoke 402 faces the first end 4011 of the first yoke 401, and the second end 4022 of the second yoke 402 faces the second end 4012 of the first yoke 401. The second yoke 402 is disposed such that the U-shaped first yoke 401 and the plate-like second yoke 402 form a ring. A resin member 49 is located within the area surrounded by the first yoke 401 and the second yoke 402.

[0028] 4, the wiring member 9 (bus bar 90) is passed through the through hole 490 of the resin member 49. Therefore, the wiring member 9 (bus bar 90) is located within the region surrounded by the first yoke 401 and the second yoke 402. The first portion 403 of the first yoke 401 and the second yoke 402 are located on opposite sides of the wiring member 9 (bus bar 90).

[0029] The second yoke 402 is arranged so as to be movable relative to the first yoke 401. More specifically, the second yoke 402 is movable in the direction in which the first yoke 401 and the second yoke 402 face each other (up and down direction).

[0030] 4, the current sensor 4 further includes a case 44. The case 44 has a hollow box shape. The case 44 is disposed below the resin member 49. The case 44 is disposed below the first yoke 401.

[0031] Here, the case 44 is fixed to the resin member 49. The case 44 is in contact with the first yoke 401 (more specifically, the first end 4011 and the second end 4012).

[0032] The second yoke 402 is housed in the case 44. The second yoke 402 is movable within the case 44. For example, the front-to-rear dimension of the internal space of the case 44 is the same as (or slightly larger than) the front-to-rear dimension of the second yoke 402, and the left-to-right dimension of the internal space of the case 44 is the same as (or slightly larger than) the left-to-right dimension of the second yoke 402. On the other hand, the up-to-down dimension of the internal space of the case 44 is larger than the up-to-down dimension of the second yoke 402. For example, the up-to-down dimension of the internal space of the case 44 is approximately twice the up-to-down dimension of the second yoke 402. This allows the second yoke 402 to move within the case 44 in the direction in which the first yoke 401 and the second yoke 402 face each other (the up-to-down direction).

[0033] The case 44 is filled with a fluid 45. The fluid 45 is a liquid in this case. The fluid 45 may be water or a liquid with a higher viscosity than water (e.g., an oil such as silicone oil). The second yoke 402 is also housed in the case 44, so the second yoke 402 moves through the fluid 45. Since the case 44 is filled with the fluid 45, the speed at which the second yoke 402 moves is slower due to the viscous force of the fluid 45 than when the inside of the case 44 is a vacuum, for example. It is preferable that the fluid 45 be a liquid that does not deteriorate or corrode the second yoke 402.

[0034] 4, the current sensor 4 further includes an elastic member 46. The elastic member 46 may be, for example, a spring, and is a coil spring in this example. The elastic member 46 biases the second yoke 402 in a direction away from the first yoke 401.

[0035] The elastic member 46 is housed in the case 44. The case 44 has an arrangement space 449 at its upper part. A first end of the elastic member 46, which is a coil spring, is disposed in the arrangement space 449 and contacts the lower surface of the upper wall of the case 44, and a second end of the elastic member 46 contacts the upper surface of the second yoke 402. The elastic member 46 applies an elastic force F2 (see FIG. 6 ) to the second yoke 402 in a direction (downward) away from the first yoke 401. As a result, the second yoke 402 is biased by the elastic member 46 in a direction away from the first yoke 401. The provision of the elastic member 46 makes it easier to maintain the second yoke 402 in a position away from the first yoke 401.

[0036] As shown in Figure 4, when the second yoke 402 is separated from the first yoke 401, a gap G1 is formed between the first end 4011 of the first yoke 401 and the first end 4021 of the second yoke 402, and a gap G2 is formed between the second end 4012 of the first yoke 401 and the second end 4022 of the second yoke 402.

[0037] As shown in FIG. 4 , the coil 41 is provided on a first yoke 401 .

[0038] The coil 41 is formed by winding a conductive conductor (e.g., copper wire) around the first portion 403 of the first yoke 401. The coil 41 is provided on the first yoke 401 via a bobbin 410 made of an insulating material such as a resin material.

[0039] 2 , the coil 41 has a first end 411 and a second end 412. The first end 411 and the second end 412 of the coil 41 are electrically connected to the filter circuit 5. For example, the first end 411 of the coil 41 is electrically connected to a first input terminal 511 of the filter circuit 5, and the second end 412 of the coil 41 is electrically connected to a second input terminal 512 of the filter circuit 5.

[0040] As described above, in the current sensor 4, the wiring member 9 (bus bar 90) is disposed within the region surrounded by the first yoke 401 and the second yoke 402. For example, during discharge of the battery 61, a current Ib flows through the wiring member 9 (bus bar 90) in a predetermined direction (the direction of the arrow of current Ib in FIG. 2 , the direction of current Ib in FIG. 4 ; hereinafter, referred to as the “positive direction”). When the current Ib flows through the wiring member 9 (bus bar 90), a magnetic field H1 is generated around the wiring member 9 (bus bar 90) in a direction corresponding to the direction of current Ib, as shown in FIG. 4 . This magnetic field H1 passes through the magnetic circuit formed by the first yoke 401 and the second yoke 402 and then through the coil 41. When the magnetic flux passing through the coil 41 changes, the coil 41 generates an induced current Ic.

[0041] Hereinafter, for convenience, the direction of the magnetic field H1 generated in the first yoke 401 by the current Ib flowing in the positive direction through the wiring member 9 (bus bar 90) (the direction of the magnetic field H1 in FIG. 4) will also be referred to as the "first direction." That is, the magnetic field H1 in the first direction is generated in the first yoke 401 in response to the current Ib flowing in a predetermined direction (positive direction) through the wiring member 9 (bus bar 90). The coil 41 generates power by the magnetic field H1 generated by the current Ib flowing in the wiring member 9 (bus bar 90).

[0042] For convenience, the direction of the induced current Ic generated by the coil 41 when the positive current Ib flowing through the wiring member 9 increases is referred to as the "positive direction." Here, the "positive induced current Ic" is a current flowing from the first end 411 of the coil 41 to the filter circuit 5 and returning from the filter circuit 5 to the second end 412 of the coil 41 (the direction of the arrow of the current Ic in FIG. 2).

[0043] (1.2.2) Operation and Advantages of the Current Sensor The operation and advantages of the current sensor 4 will be described with reference to FIGS. 5 to 12. The current sensor 4 performs at least three types of operation, including a normal operation, a first detection operation, and a second detection operation, depending on the current Ib flowing through the wiring member 9 (bus bar 90). Note that although gravity, buoyancy, and the viscous force of the fluid 45 also act on the second yoke 402, these forces are ignored here.

[0044] (1.2.2.1) Normal Operation Normal operation will be described with reference to FIGS. 5 and 6 . Normal operation refers to the operation of the current sensor 4 when no overcurrent flows through the wiring member 9 (bus bar 90). FIG. 5 is a graph showing an example of the change over time in the current Ib flowing through the wiring member 9 (bus bar 90) during normal operation. FIG. 6 is a schematic diagram showing the relative positional relationship of each part of the current sensor 4 at time t11 in FIG. 5 . Note that in FIG. 6 (and FIGS. 8 , 9 , 11 , and 12 described below), only essential parts of the current sensor 4 are shown, and the magnetic flux Φ passing through the magnetic circuit including the first yoke 401 and the second yoke 402 is generally indicated by dashed arrows.

[0045] When the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) is 0 or equal to or less than the first threshold value Ith1 (>0) and the current Ib does not change suddenly, the current sensor 4 operates normally.

[0046] For example, assume that a current Ib with a current value I11 (≦first threshold Ith1) flows through the wiring member 9 (busbar 90). In this case, a magnetic field H1 is generated in a magnetic circuit including the first yoke 401 and the second yoke 402. This magnetic field H1 generates a magnetic attraction force F1 that attracts the second yoke 402 toward the first yoke 401. However, magnetic resistance exists in the magnetic circuit including the first yoke 401 and the second yoke 402 due to the gaps G1 and G2. Therefore, the magnetic attraction force F1 in this case is sufficiently smaller than the elastic force F2 of the elastic member 46. Therefore, the second yoke 402 remains at the lower end position within the case 44 and does not move (see FIG. 6 ). In this case, the magnetic flux Φ passing through the coil 41 does not change over time, and the coil 41 does not generate an induced current Ic (does not generate electricity). That is, the current sensor 4 does not output a signal (induced current Ic) to the outside (filter circuit 5).

[0047] (1.2.2.2) First Detection Operation The first detection operation will be described with reference to FIGS. 7 to 9. The first detection operation is the operation of the current sensor 4 when a current exceeding the rated current of the wiring member 9 (bus bar 90) continues to flow through the wiring member 9 (bus bar 90) for a predetermined period of time or longer. FIG. 7 is a graph showing an example of the change over time in the current Ib flowing through the wiring member 9 (bus bar 90) during the first detection operation. FIG. 8 is a schematic diagram showing the relative positional relationship of each part of the current sensor 4 at time t21 in FIG. 7, and FIG. 9 is a schematic diagram showing the relative positional relationship of each part of the current sensor 4 at time t22 in FIG. 7.

[0048] When a current Ib larger than a first threshold Ith1 continuously flows through the wiring member 9 (bus bar 90), the current sensor 4 performs a first detection operation. The first threshold Ith1 is, for example, the rated current of the wiring member 9 (bus bar 90) or a current value larger than the rated current.

[0049] For example, assume that a current Ib having a current value I21 (>first threshold Ith1) continuously flows through the wiring member 9 (bus bar 90). In this case, the magnetic attraction force F1 generated by the current Ib becomes greater than the elastic force F2 generated by the elastic member 46. Therefore, as shown in FIG. 8 , the second yoke 402 moves upward within the case 44 toward the first yoke 401 against the elastic force F2 generated by the elastic member 46 (see FIG. 8 ). That is, the second yoke 402 moves toward the first yoke 401 due to a magnetic field H1 generated by the current Ib flowing through the wiring member 9 (bus bar 90). As the second yoke 402 moves toward the first yoke 401, the gaps G1 and G2 (see FIG. 4 ) gradually decrease, the magnetic resistance of the magnetic circuit including the first yoke 401 and the second yoke 402 gradually decreases, and the magnetic flux Φ passing through the coil 41 gradually increases.

[0050] If the magnetic attractive force F1 is sufficiently large, the second yoke 402 moves to the upper end of the case 44 against the elastic force F2 of the elastic member 46 and comes into contact with the case 44 (see FIG. 9 ). The magnetic resistance of the magnetic circuit including the first yoke 401 and the second yoke 402 rapidly decreases as the second yoke 402 approaches the first yoke 401 and the gaps G1 and G2 become smaller. In response to this rapid decrease in magnetic resistance, the magnetic flux Φ passing through the coil 41 rapidly increases. The coil 41 generates (powers) an induced current Ic in response to the sudden change (in this case, a sudden increase) in the magnetic flux Φ. In this way, the current sensor 4 instantaneously outputs a signal (induced current Ic) to the outside (filter circuit 5).

[0051] After the second yoke 402 comes into contact with the case 44 (see FIG. 9), the magnetic attraction force F1 keeps the second yoke 402 in contact with the case 44. This keeps the magnetic flux passing through the coil 41 constant, so the current sensor 4 does not output a signal (induced current Ic) to the outside (filter circuit 5).

[0052] In other words, when a relatively large current Ib continuously flows through the wiring member 9 (bus bar 90), the current sensor 4 performs the first detection operation and outputs a signal (induced current Ic). That is, the current sensor 4 can detect a relatively large current Ib that continuously flows through the wiring member 9 for a predetermined time or more.

[0053] (1.2.2.3) Second Detection Operation The second detection operation will be described with reference to FIGS. 10 to 12. The second detection operation is the operation of the current sensor 4 when the magnitude of the current flowing through the wiring member 9 (bus bar 90) momentarily becomes greater than the rated current of the wiring member 9 (bus bar 90). FIG. 10 is a graph showing an example of the change over time in the current Ib flowing through the wiring member 9 (bus bar 90) during the second detection operation. FIG. 11 is a schematic diagram showing the relative positional relationship of each part of the current sensor 4 at time t31 in FIG. 10, and FIG. 12 is a schematic diagram showing the relative positional relationship of each part of the current sensor 4 at time t32 in FIG. 10.

[0054] When the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) suddenly increases (for example, when a current Ib greater than or equal to a second threshold Ith2, which is greater than the first threshold Ith1, flows through the bus bar 90), the current sensor 4 performs a second detection operation.

[0055] For example, as shown in FIG. 10 , assume that the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) suddenly increases from a current value I11 (≦first threshold Ith1) to a current value I31 (≧second threshold Ith2). In this case, a large magnetic field H1 is generated in the magnetic circuit including the first yoke 401 and the second yoke 402 in response to the current Ib being equal to or greater than the second threshold Ith2, and the magnetic flux Φ passing through the coil 41 suddenly increases. The coil 41 generates an induced current Ic (power) in response to the sudden change (in this case, a sudden increase) in the magnetic flux Φ. In this way, the current sensor 4 instantaneously outputs a signal (induced current Ic) to the outside (filter circuit 5).

[0056] In the first detection operation described above, the current sensor 4 outputs a signal in response to a sudden increase in the magnetic flux Φ caused by a decrease in the magnetic resistance of the magnetic circuit due to a decrease in the gaps G1, G1 caused by the movement of the second yoke 402. On the other hand, in the second detection operation, the current sensor 4 outputs a signal in response to a sudden increase in the magnetic flux Φ caused by a sudden increase in the current Ib flowing through the wiring member 9 (bus bar 90) without waiting for the movement of the second yoke 402.

[0057] In other words, when the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) momentarily increases, the current sensor 4 performs the second detection operation and outputs a signal (induced current Ic). That is, the current sensor 4 can detect a current (e.g., a short-circuit current) whose magnitude momentarily increases above the rated current of the wiring member 9.

[0058] In the second detection operation, for example, after the coil 41 generates the induced current Ic, the second yoke 402 moves toward the first yoke 401 due to the magnetic attractive force F1 caused by the current Ib and comes into contact with the case 44 (see FIG. 12 ). Thereafter, if the magnitude of the current Ib is maintained at a current value I31, the second yoke 402 is maintained in contact with the case 44 due to the magnetic attractive force F1. As a result, the magnetic flux passing through the coil 41 is maintained constant, and the current sensor 4 thereafter does not output a signal (induced current Ic).

[0059] (1.2.2.4) Advantages of the Current Sensor The current sensor 4 of this embodiment can perform both the first detection operation and the second detection operation. Therefore, the current sensor 4 can detect as an overcurrent both a current that flows through the wiring member 9 continuously for a predetermined period of time or more and exceeds the rated current of the wiring member 9, and a current (e.g., a short-circuit current) that momentarily exceeds the rated current of the wiring member 9. This allows the current sensor 4 to improve the reliability of overcurrent detection.

[0060] (1.2.3) Filter Circuit The filter circuit 5 is electrically connected to the current sensor 4. As shown in FIG.

[0061] As shown in FIG. 2, the filter circuit 5 has a first input terminal 511, a second input terminal 512, a rectifying element (diode) 52, a first resistor 531, a second resistor 532, a capacitor 54, a first switching element 55, a second switching element 56, a first connection terminal 571, and a second connection terminal 572.

[0062] The diode 52 is electrically connected to both ends of the coil 41 of the current sensor 4. The cathode of the diode 52 is electrically connected to the first end 411 of the coil 41, and the anode of the diode 52 is electrically connected to the second end 412 of the coil 41.

[0063] The first resistor 531 is electrically connected to both ends of the diode 52 .

[0064] The first switching element 55 is electrically connected to the diode 52. A first end 551 of the first switching element 55 is electrically connected to the cathode of the diode 52. A second end 552 of the first switching element 55 is electrically connected to a first end 561 of the second switching element 56.

[0065] The first switching element 55 includes, for example, a thyristor. The thyristor is, for example, a bidirectional thyristor. The first switching element 55 may be a packaged element, for example, a SIDAC (registered trademark, the same applies hereinafter).

[0066] The first switching element 55 passes (almost no) current when the voltage value of the voltage applied across both ends of the first switching element 55 (between the first terminal 551 and the second terminal 552) is less than a first value. On the other hand, when a voltage equal to or greater than the first value is applied to the first switching element 55, the first switching element 55 passes current from the first terminal 551 to the second terminal 552. The first value is, for example, a breakover voltage of the first switching element 55 as a sidac.

[0067] The capacitor 54 is electrically connected to the first switching element 55. A first end of the capacitor 54 is electrically connected to a second end 552 of the first switching element 55, and a second end of the capacitor 54 is electrically connected to the anode of the diode 52. The capacitor 54 accumulates charge of the current flowing through the first switching element 55.

[0068] The second resistor 532 is electrically connected to both ends of the capacitor 54 .

[0069] The second switching element 56 is electrically connected to the first switching element 55. A first end 561 of the second switching element 56 is electrically connected to a second end 552 of the first switching element 55. A second end 562 of the second switching element 56 is electrically connected to a first connection terminal 571.

[0070] The second switching element 56 may comprise, for example, a thyristor, such as a bidirectional thyristor, or may be a packaged element, such as a sidac.

[0071] The second switching element 56 passes (almost no) current when the voltage value applied across both ends of the second switching element 56 (between the first terminal 561 and the second terminal 562) is less than a second value. On the other hand, when a voltage equal to or greater than the second value is applied, the second switching element 56 passes current from the first terminal 561 to the second terminal 562. The second value is, for example, a breakover voltage of the second switching element 56 as a sidac. The second value is, for example, the same as or greater than the first value.

[0072] 2, the filter circuit 5 may further include a rectifying element (diode) 580. As shown in Fig. 2, the anode of the diode 580 is electrically connected to the second end 562 of the second switching element 56, and is thereby electrically connected to the second end 552 of the first switching element 55 via the second switching element 56. In addition, the cathode of the diode 580 is electrically connected to the first connection terminal 571.

[0073] The first connection terminal 571 is electrically connected to the second end 562 of the second switching element 56. For example, the first connection terminal 571 is electrically connected to the second end 562 of the second switching element 56 via a diode 580. The second connection terminal 572 is electrically connected to the anode of the diode 52.

[0074] The filter circuit 5 is supplied with an induced current Ic generated in the coil 41 from the current sensor 4 .

[0075] When the induced current Ic generated in the coil 41 is zero or relatively small, the voltage value of the voltage applied to the first switching element 55 is less than the first value, so the first switching element 55 is kept off and no current flows outside the filter circuit 5.

[0076] On the other hand, if the current Ib flowing through the wiring member 9 changes significantly, for example, due to an overcurrent such as a short-circuit current flowing through the wiring member 9, the coil 41 generates a large induced current Ic. When this induced current Ic flows through the first resistor 531, a voltage equal to or greater than a first value is applied to the first switching element 55, turning on the first switching element 55. This charges the capacitor 54, and the voltage across the capacitor 54 increases. When the voltage across the capacitor 54 increases, a voltage equal to or greater than a second value is applied to the second switching element 56, turning on the second switching element 56. As a result, the current Id is supplied from the detection unit 1 to the interrupter unit 2.

[0077] For example, when a signal (induced current Ic) due to the first detection operation is supplied from the current sensor 4, the filter circuit 5 turns on the first switching element 55 and the second switching element 56 to supply the current Id to the interrupting unit 2. Furthermore, when a signal (induced current Ic) due to the second detection operation is supplied from the current sensor 4, the filter circuit 5 turns on the first switching element 55 and the second switching element 56 to supply the current Id to the interrupting unit 2.

[0078] (1.2.4) Housing The housing 19 is, for example, a hollow rectangular parallelepiped. The housing 19 has a box-shaped main body 191 with an open top, a rectangular plate-shaped lid member 192 that closes the open top of the main body 191, and a resin member 49. The housing 19 houses or holds the first yoke 401, the coil 41, the case 44, the connector 17, and the substrate 18.

[0079] As shown in FIG. 3 , a through hole 190 is formed in the housing 19. The through hole 190 in the housing 19 may be a through hole 490 in the resin member 49. The through hole 190 penetrates the housing 19 in the front-to-rear direction. The through hole 190 has a rectangular cross-sectional shape. The height dimension (dimension in the up-down direction) of the through hole 190 is greater than the width dimension (dimension in the left-to-right direction). As shown in FIGS. 3 and 4 , a bus bar 90 is passed through the through hole 490 (through hole 190).

[0080] The first yoke 401 and the second yoke 402 are disposed inside the housing 19 so that the through-hole 190 is surrounded by a magnetic circuit including the first yoke 401 and the second yoke 402 .

[0081] The connector 17 is provided with a first connection terminal 571 and a second connection terminal 572. The connector 17 protrudes from the cover member 192 of the housing 19 so that the first connection terminal 571 and the second connection terminal 572 are exposed upward.

[0082] The substrate 18 is a rectangular plate, such as a printed wiring board, and is housed in the housing 19 so that the normal direction of the substrate 18 is oriented in the vertical direction (the direction intersecting the penetration direction of the through-hole 190; the direction along the protruding direction of the connector 17).

[0083] The circuit components of the filter circuit 5 (including, in this embodiment, a diode 52, a first resistor 531, a second resistor 532, a capacitor 54, a first switching element 55, and a second switching element 56) are mounted on the substrate 18. A connector 17 is also mounted on the substrate 18. In addition, the substrate 18 is provided with conductors (pattern conductors) that connect the circuit components together, etc. Both ends (a first end 411 and a second end 412) of the coil 41 are connected to the pattern conductors of the substrate 18.

[0084] (1.3) Breaker Unit The breaker unit 2 is electrically connected to the detection unit 1. The breaker unit 2 is supplied with power generated by the coil 41.

[0085] 2 and 13, the interrupter unit 2 includes an igniter 21, a projectile 22, a conductor 23, and a housing 24. The housing 24 holds or houses the igniter 21, the projectile 22, and the conductor 23.

[0086] A first end 211 of the igniter 21 is electrically connected to a first connection terminal 571 of the detection unit 1. A second end 212 of the igniter 21 is electrically connected to a second connection terminal 572 of the detection unit 1. As a result, the igniter 21 is electrically connected to the coil 41 via the first switching element 55 and the second switching element 56. A current Id due to the power generated by the coil 41 is supplied to the igniter 21.

[0087] The igniter 21 is a so-called electric igniter. As shown in Fig. 13, the igniter 21 includes a heating element 213 and explosives 214.

[0088] The heating element 213 is, for example, a nichrome wire or an alloy wire of iron, chromium, and aluminum. The heating element 213 is electrically connected between the first end 211 and the second end 212 of the igniter 21. The heating element 213 generates heat when a current flows through the heating element 213.

[0089] 13 , the explosive 214 is disposed around the heating element 213. The explosive 214 is ignited by the heat generated by the heating element 213. Since the current Id caused by the electric power generated by the coil 41 flows through the heating element 213, it can be said that the igniter 21 is configured to be able to ignite the explosive 214 by the electric power generated by the coil 41.

[0090] In the igniter 21, when the gunpowder 214 is ignited, a large amount of gas is generated by the combustion of the gunpowder 214. The generated gas is released into the internal space 240 of the housing 24 in which the igniter 21 is housed.

[0091] 13 , the projectile 22 is disposed in an internal space 240 of the housing 24. The projectile 22 is disposed inside the housing 24 at a position between the igniter 21 and the conductor 23. The projectile 22 is held by a holder 241 provided in the housing 24. The projectile 22 is held by the holder 241 so as to face the conductor 23. The holder 241 is the inner surface of the housing 24 in this example, but may have a protrusion or the like that protrudes from the inner surface of the housing 24 and holds the projectile 22.

[0092] The projectile 22 is ejected and moves from the holder 241 under the pressure of the gas generated by the igniter 21. That is, the projectile 22 is ejected and moves in response to the ignition of the explosive 214.

[0093] The projectile 22 ejected from the holder 241 moves toward the conductor 23 and breaks it by pushing against it. The conductor 23 is, for example, at least a part of the bus bar 90 passed through the through hole 190 of the housing 19 of the detection unit 1. Therefore, the projectile 22 is configured to move toward the conductor 23 (bus bar 90) in response to the ignition of the explosive 214. Note that the bus bar 90 passed through the through hole 190 of the housing 19 may be a metal plate separate from the conductor 23 and electrically connected to the conductor 23, or may be the conductor 23 itself.

[0094] In short, in the circuit breaking device 200 of this embodiment, when a relatively large current Ib flows continuously through the wiring member 9 (bus bar 90) or when an extremely large current Ib flows instantaneously through the wiring member 9 (bus bar 90), the power generated by the coil 41 is supplied to the circuit breaking unit 2. This causes the circuit breaking unit 2 to operate and break the electric circuit 60 including the wiring member 9.

[0095] (1.4) Vehicle As described above, the blocking device 200 is mounted on, for example, a vehicle 6 as an object. The vehicle 6 may be, for example, an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, or the like.

[0096] As shown in FIG. 14 , the vehicle 6 includes a circuit breaking device 200 (a detection unit 1 and a circuit breaking unit 2 ), a battery 61 , a wiring member 9 , a motor 62 , and a control unit 30 .

[0097] The motor 62 is electrically connected to the battery 61 via the wiring member 9 .

[0098] The wiring member 9 also includes a bus bar 90. The bus bar 90 is passed through, for example, a through hole 190 in the housing 19 of the detection unit 1, and faces an inner surface 4013 of the first yoke 401 (see FIG. 4).

[0099] The control unit 30 is provided in, for example, an ECU (Electronic Control Unit) 64 of the vehicle 6. The control unit 30 controls the supply of the current Ib flowing through the wiring member 9.

[0100] In the vehicle 6 , when an overcurrent flows between the battery 61 and the motor 62 (i.e., the wiring member 9 ), the explosive 214 is ignited by the electric power generated by the coil 41 of the breaker device 200 .

[0101] Then, the projectile 22 of the interrupting unit 2 of the interrupting device 200 is ejected and moves toward the bus bar 90 (here, the conductor 23) in response to the ignition of the explosives 214, and cuts off the electrical connection between the battery 61 and the motor 62. This makes it possible to operate the interrupting unit 2 and forcibly cut off the electrical circuit 60 in the event of an accident with the vehicle 6 or an abnormality such as a short circuit in the electrical circuit 60.

[0102] 14 , in the vehicle 6 of this embodiment, the bus bar 90 (conductor 23) of the wiring member 9 has a movable portion 231 that faces the projectile 22 and a fixed portion 232 against which the movable portion 231 is pressed. The projectile 22 is projected and moves in response to the ignition of the explosive 214, and presses the movable portion 231 in a direction in which the movable portion 231 moves away from the fixed portion 232. That is, in the example of FIG. 14 , the bus bar 90 is not broken by the projectile 22, but is pushed by the projectile 22 so that the movable portion 231 moves away from the fixed portion 232, thereby interrupting the electric circuit 60 including the bus bar 90.

[0103] (2) Modifications The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the embodiment are listed below. The above embodiment and the modifications described below can be applied in appropriate combinations. In the following description of each modification, the description of the same configuration as the above embodiment may be omitted as appropriate.

[0104] In the present disclosure, the control unit 30 and the like include a computer system. The computer system is primarily composed of a processor and memory as hardware. The processor executes a program stored in the memory of the computer system to realize the functions of the control unit 30 in the present disclosure. The program may be pre-recorded in the memory of the computer system, provided via a telecommunications line, or provided in a non-transitory recording medium readable by the computer system, such as a memory card, optical disk, or hard disk drive. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The integrated circuits, such as ICs and LSIs, are referred to by different names depending on the degree of integration, and include integrated circuits called system LSIs, very large-scale integrations (VLSIs), or ultra-large-scale integrations (ULSIs). Furthermore, field-programmable gate arrays (FPGAs), which are programmed after the LSI is manufactured, or logic devices that allow the reconfiguration of internal connections or internal circuit partitions of the LSI, can also be used as processors. The electronic circuits may be integrated into one chip or distributed across multiple chips. The chips may be integrated into one device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

[0105] Furthermore, it is not essential that the multiple functions of the control unit 30 be concentrated in one housing. The components of the control unit 30 may be distributed across multiple housings. Conversely, the multiple functions of the control unit 30 may be concentrated in one housing. Furthermore, at least some of the functions of the control unit 30 may be realized by the cloud (cloud computing) or the like.

[0106] (2.1) Modification 1 As shown in FIG. 15, the current sensor 4 of this modification further includes a first magnet (permanent magnet) 47 .

[0107] The first magnet 47 is disposed on the opposite side of the second yoke 402 from the first yoke 401. The first magnet 47 is disposed, for example, on the lower side of the case 44. The first magnet 47 attracts the second yoke 402 downward. That is, the first magnet 47 attracts the second yoke 402 so that the second yoke 402 moves away from the first yoke 401.

[0108] In the current sensor 4 of this modified example, the first magnet 47 is provided, and thus a magnetic attractive force F3 from the first magnet 47 acts on the second yoke 402. Therefore, in order for the second yoke 402 to move toward the first yoke 401, the magnetic attractive force F1 caused by the current Ib flowing through the wiring member 9 (bus bar 90) needs to be greater than the resultant force of the elastic force F2 caused by the elastic member 46 and the magnetic attractive force F3. In short, by providing the first magnet 47, it is possible to change the magnitude (threshold value) of the current Ib at which the second yoke 402 begins to move, compared to the case of the current sensor 4 of the above embodiment, which does not have the first magnet 47.

[0109] The current sensor 4 may further include a movement mechanism for moving the position of the first magnet 47. The movement mechanism moves the first magnet 47, for example, vertically, so as to change the distance between the first magnet 47 and the second yoke 402. Changing the distance between the first magnet 47 and the second yoke 402 makes it possible to change the magnitude of the magnetic attractive force F3 acting on the second yoke 402, and therefore the magnitude (threshold) of the current Ib at which the second yoke 402 begins to move. The movement mechanism may be controlled by, for example, the control unit 30.

[0110] (2.2) Modification 2 As shown in FIG. 16 , the current sensor 4 of this modification further includes a second magnet (permanent magnet) 48. The second magnet 48 generates a magnetic field H3 that passes through the first yoke 401. The direction of the magnetic field H3 generated in the first yoke 401 by the second magnet 48 may be the same as the direction (first direction) of the magnetic field H1 generated in the first yoke 401 by the current Ib flowing through the wiring member 9 (bus bar 90), for example. That is, the magnetic field H1 of the first direction is generated in the first yoke 401 in response to the current Ib flowing through the wiring member 9 (bus bar 90), and the second magnet 48 generates a magnetic field of the first direction in the first yoke 401.

[0111] In the current sensor 4 of this modified example, even when no current Ib flows through the wiring member 9 (bus bar 90), a magnetic attraction force F4 is applied to the second yoke 402 by the magnetic field H3 of the second magnet 48 in a direction toward the first yoke 401. However, because the magnetic attraction force F4 of the second magnet 48 is smaller than the elastic force F2 of the elastic member 46, the second yoke 402 does not move.

[0112] When a current Ib equal to or greater than the first threshold value Ith1 flows through the wiring member 9 (bus bar 90), the second yoke 402 receives a magnetic attraction force F1 due to a magnetic field H1 of the current Ib, and moves toward the first yoke 401 to the upper end of the case 44. After the second yoke 402 comes into contact with the case 44, the second yoke 402 is maintained in contact with the case 44 by the magnetic attraction force F1.

[0113] In the current sensor 4 of the above embodiment, after the second yoke 402 has moved to the upper end (see FIGS. 9 and 12), when the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) decreases (for example, becomes 0), the magnetic attractive force F1 also decreases (for example, becomes 0). Therefore, the elastic force F2 becomes larger than the magnetic attractive force F1, and the second yoke 402 moves downward away from the first yoke 401 due to the elastic force F2.

[0114] On the other hand, in the current sensor 4 of this modified example, even if the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) decreases to, for example, zero, a magnetic attractive force F4 due to the magnetic field H3 of the second magnet 48 acts on the second yoke 402 (see FIG. 17 ). The magnetic attractive force F4 in this state (see FIG. 17 ) is greater than the magnetic attractive force F4 in the state in which the second yoke 402 is separated from the first yoke 401 (see FIG. 16 ), and is set greater than the elastic force F2 of the elastic member 46 in the current sensor 4 of this modified example. Therefore, in the current sensor 4 of this modified example, the second yoke 402 remains close to the first yoke 401 even if the magnitude of the current Ib flowing through the wiring member 9 (bus bar 90) becomes zero. In other words, in the current sensor 4 of this modified example, the second yoke 402 is maintained in a position close to the first yoke 401 even if the current Ib flowing through the wiring member 9 decreases.

[0115] The second magnet 48 may be disposed outside the coil 41 as shown in Fig. 16 or inside the coil 41 as shown in Fig. 18. A part of the second magnet 48 may be disposed inside the coil 41 and the remaining part may be disposed outside the coil 41.

[0116] Furthermore, the current sensor 4 may include a first magnet 47 (see FIG. 15 ) in addition to the second magnet 48 .

[0117] 19 , in a current sensor 4 of this modification, the case 44 is not provided, and the first yoke 401 and the second yoke 402 are connected by a hinge structure 408. For example, a first end 4011 of the U-shaped first yoke 401 and a first end 4021 of the flat plate-shaped second yoke 402 are connected by the hinge structure 408. The second yoke 402 is rotatable relative to the first yoke 401 around the hinge structure 408.

[0118] The current sensor 4 of this modified example also makes it possible to improve the reliability of overcurrent detection.

[0119] 20 , the filter circuit 5 does not necessarily have to include the second switching element 56. In the filter circuit 5 of this modification, the second resistor 532 and the capacitor 54 are also omitted in accordance with the omission of the second switching element 56. The rectifying element (diode) 52 is also omitted.

[0120] (2.5) Modification 5 In the filter circuit 5, the first switching element 55 may include a unidirectional thyristor 553. For example, as shown in FIG. 21A , the anode of the unidirectional thyristor 553 is electrically connected to the first terminal 551 of the first switching element 55, and the cathode of the unidirectional thyristor 553 is electrically connected to the second terminal 552 of the first switching element 55.

[0121] 14A , the first switching element 55 further includes a diode 554, a Zener diode 555, a resistor 556, and a capacitor 557. A series circuit of the diode 554 and the Zener diode 555 is electrically connected between the anode and gate of the unidirectional thyristor 553. The cathodes of the diode 554 and the Zener diode 555 are electrically connected to each other. A parallel circuit of the resistor 556 and the capacitor 557 is electrically connected between the gate and cathode of the unidirectional thyristor 553.

[0122] 21B , the second switching element 56 may include a unidirectional thyristor 563. For example, as shown in FIG. 21B , the anode of the unidirectional thyristor 563 is electrically connected to a first end 561 of the second switching element 56, and the cathode of the unidirectional thyristor 563 is electrically connected to a second end 562 of the second switching element 56.

[0123] 14B , the second switching element 56 further includes a diode 564, a Zener diode 565, a resistor 566, and a capacitor 567. A series circuit of the diode 564 and the Zener diode 565 is electrically connected between the anode and gate of the unidirectional thyristor 563. The cathodes of the diode 564 and the Zener diode 565 are electrically connected to each other. A parallel circuit of the resistor 566 and the capacitor 567 is electrically connected between the gate and cathode of the unidirectional thyristor 563.

[0124] (2.6) Other Modifications In one modification, the case 44 of the current sensor 4 does not need to be filled with the fluid 45 and may be, for example, a vacuum. Furthermore, the current sensor 4 may be provided with a guide structure that guides the movement direction of the second yoke 402 instead of or in addition to the case 44. The guide structure may include, for example, grooves extending vertically that are formed on the left and right inner surfaces of the case 44, and protrusions that protrude from the left and right side surfaces of the second yoke 402 and fit into the grooves of the case 44.

[0125] In one modified example, the coil 41 may be provided on the second yoke 402. In this case, when the second yoke 402 moves, the coil 41 also moves together with the second yoke 402.

[0126] In one modified example, the current sensor 4 does not need to include the elastic member 46. Even without the elastic member 46, the second yoke 402 can be maintained separated from the first yoke 401 by, for example, gravity, the viscous force of the fluid 45, or the like, when no current Ib flows through the wiring member 9 (bus bar 90).

[0127] In one modified example, contact portions 441, 442 (see FIG. 4 ) of the case 44 that come into contact with the first end 4011 and the second end 4012 of the first yoke 401 may be formed of a magnetic material. Alternatively, through holes may be formed in portions of the case 44 that correspond to the first end 4011 and the second end 4012 of the first yoke 401, and the first end 4011 and the second end 4012 of the first yoke 401 may be exposed to the internal space of the case 44 through the through holes.

[0128] In one variant, the sensing unit 1 may not include a filter circuit 5 .

[0129] In one variant, the filter circuit 5 may not include a rectifying element (diode 580).

[0130] In one modification, at least one of the first switching element 55 and the second switching element 56 may be a switching element other than a sidac, such as a diac.

[0131] In one variant, not only the second yoke 402 but also the first yoke 401 may be movable.

[0132] (3) Aspects As is clear from the above-described embodiments and modifications, the present specification discloses the following aspects.

[0133] The current sensor (4) of the first aspect includes a first yoke (401), a second yoke (402), and a coil (41). The first yoke (401) has an inner surface (4013) facing the wiring member (9). The second yoke (402) moves toward the first yoke (401) due to a magnetic field (H1) generated by a current (Ib) flowing through the wiring member (9). The coil (41) is provided on the first yoke (401) or the second yoke (402).

[0134] According to this aspect, it is possible to improve the reliability of overcurrent detection.

[0135] The current sensor (4) of the second aspect is the same as the first aspect, and further includes a case (44). The case (44) houses the second yoke (402) and is filled with a fluid (45).

[0136] According to this embodiment, the moving speed of the second yoke (402) can be slower than when the case (44) is not provided.

[0137] In the current sensor (4) of the third aspect, the fluid (45) is water or a liquid having a viscosity greater than that of water in the second aspect.

[0138] According to this embodiment, the moving speed of the second yoke (402) can be slowed down.

[0139] The current sensor (4) of the fourth aspect is any one of the first to third aspects, and further includes an elastic member (46) that biases the second yoke (402) so that the second yoke (402) moves away from the first yoke (401).

[0140] According to this embodiment, it becomes easier to maintain the second yoke (402) at a position separated from the first yoke (401).

[0141] In the current sensor (4) of the fifth aspect, in any one of the first to fourth aspects, the first yoke (401) is U-shaped and surrounds the wiring member (9) from three sides, and has a first end (4011) and a second end (4012). The second yoke (402) is plate-shaped and faces the first end (4011) and the second end (4012) of the first yoke (401).

[0142] According to this aspect, it is easy to form a ring-shaped magnetic circuit including the first yoke (401) and the second yoke (402).

[0143] The current sensor (4) of the sixth aspect is, in any one of the first to fifth aspects, further provided with a first magnet (47) that attracts the second yoke (402) so that the second yoke (402) moves away from the first yoke (401).

[0144] According to this aspect, it is possible to change the magnitude (threshold value) of the current (Ib) at which the second yoke (402) starts to move compared to the case where the first magnet (47) is not present.

[0145] The current sensor (4) of the seventh aspect is the current sensor of any one of the first to sixth aspects, further comprising a second magnet (48) that generates a magnetic field (H1) passing through the first yoke (401).

[0146] According to this aspect, even if the current (Ib) flowing through the wiring member (9) becomes small, the second yoke (402) can be easily held in a position close to the first yoke (401).

[0147] In the current sensor (4) of the eighth aspect, in the seventh aspect, a current (Ib) flows in a predetermined direction through the wiring member (9). A magnetic field (H1) of a first direction is generated in the first yoke (401) in response to the current (Ib) flowing through the wiring member (9). The second magnet (48) generates the magnetic field (H1) of the first direction in the first yoke (401).

[0148] According to this aspect, even if the current (Ib) flowing through the wiring member (9) becomes small, the second yoke (402) can be easily held in a position close to the first yoke (401).

[0149] A circuit breaker (200) of a ninth aspect includes the current sensor (4) of any one of the first to eighth aspects and a circuit breaker unit (2). The circuit breaker unit (2) is supplied with power generated by a coil (41). The circuit breaker unit (2) has an igniter (21) and a projectile (22). The igniter (21) includes explosives (214) and is configured to be able to ignite the explosives (214) with the power generated by the coil (41). The projectile (22) moves in response to the ignition of the explosives (214).

[0150] According to this aspect, it is possible to provide a circuit breaker (200) equipped with a current sensor (4) that has improved reliability in detecting overcurrent.

[0151] A vehicle (6) of a tenth aspect includes the interrupter (200) of the ninth aspect, a battery (61), a wiring member (9), a motor (62), and a control unit (30). The motor (62) is electrically connected to the battery (61) via the wiring member (9). The control unit (30) controls the supply of a current (Ib) flowing through the wiring member (9). In the vehicle (6), when an overcurrent flows between the battery (61) and the motor (62), the explosive (214) is ignited by the electric power generated by the coil (41). The projectile (22) is configured to move toward the wiring member (9) in response to the ignition of the explosive (214) and interrupt the electrical connection between the battery (61) and the motor (62).

[0152] According to this aspect, it is possible to improve the reliability of overcurrent detection by the current sensor (4) of the breaker (200) provided in the vehicle (6).

[0153] 200 Breaker device 2 Breaker unit 21 Igniter 214 Explosive 22 Projectile 30 Control unit 4 Current sensor 401 First yoke 4011 First end 4012 Second end 4013 Inner surface 402 Second yoke 41 Coil 44 Case 45 Fluid 46 Elastic member 47 First magnet 48 Second magnet 6 Vehicle 61 Battery 62 Motor 9 Wiring member H1 Magnetic field Ib Current

Claims

1. A current sensor comprising: a first yoke having an inner surface facing a wiring member; a second yoke that moves toward the first yoke due to a magnetic field generated by a current flowing through the wiring member; and a coil provided on the first yoke or the second yoke.

2. The current sensor according to claim 1, further comprising a case containing said second yoke and filled with a fluid.

3. The current sensor according to claim 2, wherein the fluid is water or a liquid having a viscosity greater than that of water.

4. The current sensor according to any one of claims 1 to 3, further comprising an elastic member that biases the second yoke so as to move away from the first yoke.

5. A current sensor as described in any one of claims 1 to 4, wherein the first yoke is U-shaped surrounding the wiring member on three sides and has a first end and a second end, and the second yoke is plate-shaped facing the first end and the second end of the first yoke.

6. The current sensor according to any one of claims 1 to 5, further comprising a first magnet that attracts the second yoke so as to move the second yoke away from the first yoke.

7. The current sensor according to any one of claims 1 to 6, further comprising a second magnet that generates a magnetic field passing through the first yoke.

8. The current sensor according to claim 7, wherein a current flows through the wiring member in a predetermined direction, a magnetic field of a first direction is generated in the first yoke in response to the current flowing through the wiring member, and the second magnet generates a magnetic field of the first direction in the first yoke.

9. A circuit breaker comprising: a current sensor according to any one of claims 1 to 8; and an interrupter unit to which power generated by the coil is supplied, the circuit breaker unit having: an igniter including explosives and configured to be able to ignite the explosives by the power generated by the coil; and a projectile that moves in response to the ignition of the explosives.

10. A vehicle comprising the circuit breaking device of claim 9; a battery; the wiring member; a motor electrically connected to the battery via the wiring member; and a control unit which controls the supply of the current flowing through the wiring member, wherein when an overcurrent flows between the battery and the motor, the explosive is ignited by the power generated by the coil, and the projectile is configured to move toward the wiring member in response to the ignition of the explosive, thereby cutting off the electrical connection between the battery and the motor.

Images