阅读说明：本技术 电流传感器 (Current sensor ) 是由 佐藤裕太 市桥弘英 富田满 小林昌一 桥本学 于 2020-03-26 设计创作，主要内容包括：电流传感器检测在电导体中流动的电流。该电流传感器包括：芯,其具有供电导体贯穿的中空部；以及线圈,其卷绕于芯。芯实质上具有局部形成有与中空部相连的间隙的C字形状。芯的间隙的至少一部分位于线圈内。该电流传感器能够抑制外部噪声的影响。(The current sensor detects a current flowing in the electrical conductor. The current sensor includes: a core having a hollow portion through which a current supply conductor passes; and a coil wound around the core. The core substantially has a C-shape in which a gap connected to the hollow portion is partially formed. At least a portion of the gap of the core is located within the coil. The current sensor can suppress the influence of external noise.)

1. A current sensor that detects a current flowing in an electrical conductor, wherein,

the current sensor includes:

a core having a hollow portion through which the electrical conductor passes; and

a coil wound around the core,

the core substantially has a C-shape partially formed with a gap continuous with the hollow portion,

at least a portion of the gap of the core is located within the coil.

2. The current sensor of claim 1,

the core has a pair of end faces opposed to each other with the gap therebetween,

the pair of end faces of the core are located within the coil.

3. The current sensor according to claim 1 or 2,

the current sensor further includes a bobbin formed of a non-magnetic body and surrounding the gap of the core, the coil being wound around the bobbin.

4. Current sensor according to any one of claims 1 to 3,

the core has a plurality of split cores joined to each other.

5. The current sensor of claim 4,

the current sensor further includes:

a first housing having a first body portion having a space for housing a first split core of the plurality of split cores; and

a second housing having a second body portion having a space for housing a second split core of the plurality of split cores,

the first split core, the second split core, and the coil are fixed to each other by integrating the first case and the second case.

6. The current sensor of claim 5,

the second housing further has a rib projecting from the second main body portion toward a space for positioning the second split core,

the rib has:

a base portion protruding from the second body portion toward the space; and

a positioning portion extending from the base portion toward the second split core, having an opposing surface opposing the second split core, for positioning the second split core,

the positioning portion of the rib is separated from the second main body portion via a slit extending from the opposing surface of the positioning portion.

7. The current sensor according to claim 5 or 6,

the first case has a rib configured to be fitted into the space so as to abut against the second body portion of the second case when the first case and the second case are integrated.

8. Current sensor according to any one of claims 5 to 7,

the current sensor further includes a buffer pad disposed between the first body portion and the first split core.

9. Current sensor according to any one of claims 5 to 8,

the first case and the second case are integrated so that the joint surface of the first split core is joined to the joint surface of the second split core,

an end of the joint surface of the first split core is chamfered.

10. The current sensor of claim 9,

both ends of the joint surface of the first split core are chamfered.

11. Current sensor according to any one of claims 5 to 8,

the first case and the second case are integrated so that the joint surface of the first split core is joined to the joint surface of the second split core,

an end of the joint surface of the second split core is chamfered.

12. The current sensor of claim 11,

both ends of the joint surface of the second split core are chamfered.

Technical Field

The present disclosure relates to a current sensor.

Background

Patent document 1 discloses a conventional current sensor in which an electric conductor is disposed as an annular core through which a coil is partially wound. In the current sensor, the annular core is divided to facilitate arrangement of the electric conductor within the annular core. In assembly, the electrical conductors are first arranged in the divided cores, and then the cores are assembled so that the electrical conductors are arranged to penetrate through the annular cores.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 9-166625

Disclosure of Invention

The current sensor detects a current flowing in the electrical conductor. The current sensor includes: a core having a hollow portion through which a current supply conductor passes; and a coil wound around the core. The core substantially has a C-shape in which a gap connected to the hollow portion is partially formed. At least a portion of the gap of the core is located within the coil.

The current sensor can suppress the influence of external noise.

Drawings

Fig. 1 is a perspective view of a current sensor according to an embodiment.

Fig. 2 is an exploded perspective view of the current sensor according to the embodiment.

Fig. 3 is a cross-sectional view of the current sensor shown in fig. 1 at line III-III.

Fig. 4 is a perspective view of a sensor unit of the current sensor of the embodiment.

Fig. 5 is an exploded perspective view of the sensor unit of the embodiment.

Fig. 6 is a plan view of the sensor unit of the embodiment.

Fig. 7 is a graph showing a BH curve of ferrite as a material of a core of an embodiment.

Fig. 8 is an explanatory diagram for comparing output waveforms of the core of the embodiment and the core of the comparative example.

Fig. 9 is a graph showing a relationship between a gap of a core and an output of the current sensor according to the embodiment.

Fig. 10A is a front view of another core of an embodiment.

Fig. 10B is a side view of the core shown in fig. 10A.

Fig. 11 is a graph showing the current and output of the core of the embodiment.

Fig. 12 is a top view of yet another core of an embodiment.

Fig. 13 is a top view of yet another core of an embodiment.

Fig. 14A is an explanatory diagram showing an influence of the electric conductor of the core of modification 1.

Fig. 14B is an explanatory diagram showing an influence of the electric conductor of the core of modification 2.

Fig. 14C is an explanatory diagram showing an influence of the electric conductor of the core of the embodiment.

Fig. 15 is an explanatory diagram showing the core and the output of the current sensor according to the embodiment.

Fig. 16 is an explanatory diagram showing a core and an output chart of the current sensor according to the embodiment.

Fig. 17 is an explanatory diagram showing the core and the output of the current sensor according to the embodiment.

Fig. 18 is a perspective view of another current sensor of the embodiment.

FIG. 19 is a cross-sectional view of the current sensor shown in FIG. 18 at line XIX-XIX.

FIG. 20 is a cross-sectional view of the current sensor shown in FIG. 18 at line XX-XX.

Fig. 21 is a perspective view of the case of the current sensor shown in fig. 18.

Fig. 22 is an enlarged sectional view of the current sensor shown in fig. 19.

Fig. 23 is a perspective view of a sensor unit of the current sensor shown in fig. 18.

Fig. 24 is a perspective view of another sensor unit of the current sensor shown in fig. 18.

Detailed Description

The embodiments described below are all specific examples of the present disclosure. The numerical values, shapes, materials, constituent elements, arrangement positions and connection modes of the constituent elements, steps, order of the steps, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure. Among the components of the following embodiments, components that are not recited in the independent claims that illustrate one embodiment of the present disclosure will be described as arbitrary components. Implementations of the present disclosure may also be presented in other independent claims, and are not limited to the present independent claims.

[ embodiment ]

[ Structure of Current sensor ]

Fig. 1 is a perspective view showing a schematic configuration of a current sensor 10 according to an embodiment. Fig. 2 is an exploded perspective view of the current sensor 10. Fig. 3 is a cross-sectional view of the current sensor 10 shown in fig. 1 at line III-III. In fig. 1, a linear electric conductor W to be detected is indicated by a broken line. In the following description, the X-axis direction is sometimes referred to as the width direction X, the Y-axis direction is sometimes referred to as the thickness direction Y, and the Z-axis direction is sometimes referred to as the vertical direction Z.

The Current sensor 10 is a Current Transformer (CT) type Current sensor that detects an ac Current flowing through an electric conductor W. The current sensor 10 includes a case 20 and a sensor unit 30 housed in the case 20.

The case 20 is formed of, for example, a non-magnetic resin in a substantially rectangular parallelepiped shape as a whole. The thickness (length in the Y-axis direction) of the housing 20 is constant as a whole. The housing 20 is divided into two housings 21 and 22 in the Z-axis direction, a portion in the negative side direction of the Z-axis is the housing 21, and a portion in the positive side direction of the Z-axis is the housing 22.

The housing 21 includes a body portion 211 and a pair of locking portions 212 locked to the housing 22, and the body portion 211 has a box-like shape having a space 21s opened in the direction of the Z-axis positive side. The body portion 211 has a pair of lower wall portions 213 opposed to each other in the Y-axis direction, a pair of lower wall portions 214 opposed to each other in the X-axis direction, and a bottom plate portion 219. The lower wall portions 213 and 214 are connected to each other and extend from the bottom plate portion 219 toward the Z-axis positive side. The lower wall portions 213 and 214 and the bottom plate portion 219 surround the space 21 s. Further, a pair of inner wall portions 215 parallel to the lower wall portion 213 is provided inside the housing 21. The pair of inner wall portions 215 are disposed with a predetermined gap therebetween in the Y-axis direction. A part of the sensor unit 30 is fitted and fixed between the pair of inner wall portions 215. Further, a notch 213a having a semicircular arc shape is formed in the pair of lower wall portions 213. A semicircular arc-shaped notch 215a is formed in the pair of inner wall portions 215.

The pair of locking portions 212 extend from the outer surfaces of the pair of lower wall portions 214 in the direction toward the positive side of the Z axis. The pair of locking portions 212 has a substantially U-shape. The pair of locking portions 212 are respectively engaged with the plurality of engaging projections 228a and 228b of the case 22, and the case 21 and the case 22 are integrated and fixed to each other.

The housing 22 has a space 22s opened in the direction of the negative side of the Z axis, and has a box shape. The housing 22 has a pair of upper wall portions 223 opposing each other in the Y-axis direction, a pair of upper wall portions 224 opposing each other in the X-axis direction, and a bottom plate portion 229. The upper wall portions 223, 224 are connected to each other and extend from the bottom plate portion 229 to the negative side of the Z axis. The upper wall portions 223, 224 and the bottom plate portion 229 surround the space 22 s.

The pair of upper wall portions 223 are formed with semicircular arc-shaped notches 223a, respectively. In the assembled state of case 21 and case 22, notch 223a forms through hole 20h shown in fig. 1 together with notch 213a of case 21. The electric conductor W penetrates the through hole 20 h. In this state, the electric conductor W is also accommodated in the notch 215a of the pair of inner wall portions 215 of the housing 21. The cutouts 213a, 215a, and 223a also function as support portions for supporting the electric conductors W.

A pair of protrusions 224a that sandwich the sensor unit 30 in the Y-axis direction are formed on the inner surfaces of the pair of upper wall portions 224, respectively. Only the projection 224a in the direction of the positive side of the Y axis out of the pair of projections 224a is illustrated in fig. 3. A pair of projections 224a extend in the Z-axis direction. The pair of projections 224a are arranged with a predetermined gap therebetween in the Y-axis direction. A part of the fixed sensor unit 30 is embedded between the pair of projections 224 a.

Further, on the inner surfaces of the pair of upper wall portions 224, restricting convex portions 224b for restricting the vertical displacement of the sensor unit 30 are provided. The restricting convex portion 224b is disposed between the pair of projections 224a and extends in the Z-axis direction. The lower end surface of the restricting projection 224b abuts against the upper end surface of the sensor unit 30 to restrict the displacement of the sensor unit 30 in the vertical direction Z with respect to the housing 20.

Three engaging projections 228a, 228b are provided on the outer side surfaces of the pair of upper wall portions 224, respectively. Two of the three engaging projections 228a, 228b are provided at the lower end of the upper wall portion 224 and are arranged at a predetermined interval from each other in the Y-axis direction. The two engaging projections 228b sandwich the locking portion 212 of the housing 21 in the Y-axis direction. On the other hand, the remaining one of the engaging projections 228a is disposed above the vicinity of the center of the two engaging projections 228b in the Y axis direction. The engaging projection 228b supports the upper portion of the locking portion 212 of the housing 21 from below. The three engaging projections 228a and 228b are engaged with the engaging portion 212 in this state, so that relative displacement between the housing 21 and the housing 22 is restricted, and the two are integrated and fixed to each other.

Next, the sensor unit 30 will be explained. Fig. 4 is a perspective view showing a schematic configuration of the sensor unit 30 according to the embodiment. Fig. 5 is an exploded perspective view of the sensor unit 30 of the embodiment. Fig. 6 is a plan view of the sensor unit 30 of the embodiment.

As shown in fig. 4 to 6, the sensor unit 30 includes a core 40, a bobbin 50, and a coil 60.

The core 40 is formed of a magnetic body such as ferrite, has a hollow portion 40h and a gap S continuous with the hollow portion 40h, and has a substantially C-shape. Specifically, the core 40 has a rectangular frame shape in plan view. The gap S is provided in the center of the rectangular frame-shaped upper frame portion. The cross sections of the four outer corners of the core 40 are corners with sharp tips, and the cross sections of the four inner corners are corners with circular arc shapes. The cross section of the outer four corners may have a circular arc shape, and the cross section of the inner four corners may have a corner portion with a sharp tip. The outer shape of the core 40 may be other than the rectangular frame shape, and may have other frame shapes such as a polygonal frame shape, a circular frame shape, a rectangular frame shape, and an elliptical frame shape.

The core 40 is formed of a plurality of split cores 41, 42, 43 joined to each other. Specifically, the split core 41 forms a lower portion of the core 40, and the split cores 42 and 43 form an upper portion of the core 40.

The split core 41 has a substantially U-shape with an open upper side. The pair of distal end surfaces of the split core 41 is formed in an upward facing posture and is the joint surfaces 411 and 412 to be joined to the other split cores 42 and 43. The pair of engagement surfaces 411, 412 are planes parallel to an XY plane including the X axis and the Y axis. The joint surface 411 is arranged in the direction of the negative side of the X axis, and the joint surface 412 is arranged in the direction of the positive side of the X axis.

The segment core 42 has a substantially L-shape. One end surface of the split core 42 is a joint surface 421 to which the joint surface 411 of the split core 41 is joined. The bonding surface 421 of the segment core 42 is a plane parallel to the XY plane. The joint surface 421 of the divided core 42 is joined to the joint surface 411 of the divided core 41 in a posture in which the other end surface 422 of the divided core 42 faces the positive side of the X axis. The other end surface 422 of the split core 42 is a plane parallel to a YZ plane including the Y axis and the Z axis.

The split core 43 has a substantially L-shape. The split core 43 is the same member as the split core 42. One end surface of the segment core 43 is a joint surface 431 to be joined to the joint surface 412 of the segment core 41. The joint surface 431 of the segment core 43 is a plane parallel to the XY plane. The joint surface 431 of the split core 43 is joined to the joint surface 412 of the split core 41 in a posture in which the other end surface 432 of the split core 43 faces in the negative X-axis direction. The other end surface 432 of the split core 43 is a plane parallel to the YZ plane.

Each pair of the split cores adjacent to each other among the plurality of split cores 41, 42, 43 has a joint surface parallel to the opposing direction DX. In detail, the other end face 422 of the segment core 42 is opposed to the other end face 432 of the segment core 43 in the opposed direction DX parallel to the X axis. A gap S is formed between the other end surface 422 of the split core 42 of the core 40 and the other end surface 432 of the split core 43. That is, the other end face 422 of the core 42 faces the other end face 432 of the split core 43 with the gap S therebetween in the opposing direction DX. By adjusting the interval LX (length in the X-axis direction) in the opposing direction DX of the gap S before assembling the current sensor 10, a desired sensitivity characteristic can be achieved. As described above, both the joint surface 411 of the divided core 41 and the joint surface 412 of the divided core 42 are planes parallel to the XY plane. Therefore, by sliding the joint surface 411 of the split core 41 and the joint surface 421 of the split core 42 with each other to move the split core 42, the position of the other end surface 422 of the split core 42, that is, the interval LX of the gap S can be adjusted in the X-axis direction. The same applies to the relationship between the joint surface 412 of the segment core 41 and the joint surface 431 of the segment core 43. In the present embodiment, the interval LX of the gap S achieves a desired sensitivity characteristic in a state where the outer side surfaces of the pair of split cores 42 and 43 are flush with the outer side surface of the split core 41. In order to realize desired sensitivity characteristics, it is preferable that no conductive member is disposed in the gap S.

A boundary portion is generated in the annular core formed of the divided cores due to assembly. Since a minute gap exists in the boundary portion, the boundary portion may affect current detection, which may result in a decrease in sensitivity.

In the current sensor 10 of the embodiment, as described above, a desired sensitivity characteristic can be achieved.

In the embodiment, both the joint surface 411 of the divided core 41 and the joint surface 421 of the divided core 42 are planes parallel to the XY plane. However, both the joint surface 411 of the divided core 41 and the joint surface 421 of the divided core 42 may be provided to extend parallel to the X-axis direction and be inclined with respect to the Y-axis direction. In this case, the position of the other end surface 422 of the divided core 42 can be adjusted in the X-axis direction by sliding the joint surface 411 of the divided core 41 and the joint surface 421 of the divided core 42 relative to each other and moving the divided core 42. The joint surface 411 of the divided core 41 and the joint surface 421 of the divided core 42 may be curved surfaces as long as they are in surface contact with each other.

The bobbin 50 is formed of a non-magnetic body such as resin. Specifically, the bobbin 50 includes a bobbin main body 51 having a square tube shape and a pair of flange portions 52 protruding from both ends of the bobbin main body 51 in the X axis direction. The pair of flange portions 52 project from the both ends of the bobbin main body 51 over the entire circumference in the direction perpendicular to the X axis. The bobbin body 51 extends in the X-axis direction. The coil 60 is wound around a winding axis 60c extending in the X-axis direction on the outer periphery of the bobbin main body 51. The wound coil 60 is housed between the pair of flange portions 52. A pair of inner spaces 50s are provided in the bobbin 50, i.e., the bobbin body 51, along the winding axis 60 c.

As shown in fig. 3, an inner bottom portion 53 is provided at the center of the inside of the bobbin main body 51, and the inner bottom portion 53 blocks the pair of inner spaces 50s of the bobbin main body 51 from each other. The end portion including the end face 422 of the split core 42 and the end portion including the end face 432 of the split core 43 are fitted into the pair of openings 50p opened in the pair of inner spaces 50s of the bobbin body 51 in contact with the inner bottom portion 53. That is, the bobbin 50 is provided so as to fit the pair of other end surfaces 422 and 432 of the core 40 and surround the gap S. Thus, the gap S between the other end surface 422 of the split core 42 and the other end surface 432 of the split core 43 is defined by the inner bottom portion 53. The thickness (length in the X-axis direction) of the inner bottom portion 53 has a value corresponding to the interval LX of the gap S. That is, the thickness of the inner bottom portion 53 is adjusted in advance so as to be the interval LX that can achieve a desired sensitivity characteristic.

The coil 60 is a conductive wire, and is wound around the bobbin main body 51 by a plurality of turns. As described above, since the end portion of the split core 42 and the end portion of the split core 43 are press-fitted into the pair of internal spaces 50s of the bobbin body 51, the pair of other end surfaces 422 and 432 of the core 40 are disposed inside the coil 60.

The operation of the current sensor 10 will be described below. When a magnetic flux is generated in the core 40 by the alternating current flowing in the electric conductor W, an alternating current flows in the coil 60 to cancel the magnetic flux. Measurement devices are connected to both ends of the coil 60, and the measurement devices can detect and measure the alternating current flowing through the electric conductor W based on the alternating current flowing through the coil 60.

[ method of assembling Current sensor ]

Next, a method of assembling the current sensor 10 will be described. The current sensor 10 can be assembled by an operator or an assembling apparatus, and the case of assembling by the operator will be described here.

First, the worker prepares the bobbin 50 in which the coil 60 is wound around the bobbin body 51 with a predetermined number of turns. The operator inserts the end of the divided core 42 and the end of the divided core 43 into the pair of openings 50p of the bobbin body 51. At this time, the operator brings the end surface 422 of the split core 42 and the end surface 432 of the split core 43 into abutment with the inner bottom portion 53. Thereby, the other end surfaces 422 and 432 face each other with the gap S of the interval LX.

After that, the worker assembles the bobbin 50 and the pair of split cores 42 and 43 on the case 22. Specifically, the worker inserts the integrated bobbin 50 and the pair of split cores 42 and 43 between the pair of projections 224a from below the case 22. At this time, the operator slides the bobbin 50 and the pair of split cores 42 and 43 relative to the case 22 until the upper end surfaces of the pair of split cores 42 and 43 come into contact with the restricting convex portion 224b of the case 22. Thereby, the bobbin 50 and the pair of split cores 42 and 43 are fixed inside the case 22. The split cores 42 and 43 are press-fitted into the space 50s so as to abut against the inner bottom 53 of the bobbin 50 and so as to abut against the bobbin body 51, and are firmly fixed to the bobbin 50. Thus, the bobbin 50 and the split cores 42 and 43 can be easily fixed to the case 22.

On the other hand, the worker assembles the split core 41 to the case 21. Specifically, the operator inserts the split core 41 between the pair of inner wall portions 215 from above the housing 21. At this time, the operator slides the split core 41 with respect to the case 21 until the lower end surface of the split core 41 comes into contact with the inner bottom surface of the case 21. Thereby, the split core 41 is fixed inside the case 21.

Next, the worker assembles the electric conductor W on the case 21 and the split core 41. Specifically, the operator accommodates electric conductor W in notches 213a, 215a, and 223a of case 21. Thus, the electric conductor W is supported by the notches 213a, 215a, and 223a and is disposed on the open end side of the split core 41.

Next, the worker assembles case 22 to case 21 supporting electric conductor W. During assembly, the operator engages the locking portion 212 of the housing 21 with the plurality of engaging projections 228a and 228b provided on the respective upper wall portions 224 of the housing 22. Thereby, the case 21 and the case 22 are integrated. Inside the case 21 and the case 22, the joint surface 421 of the split core 42 is joined to the joint surface 411 of the split core 41, and the joint surface 431 of the split core 43 is joined to the joint surface 412 of the split core 41. Thereby, the assembly of the current sensor 10 is completed.

In the current sensor 10, when the housings 21 and 22 are displaced relative to each other by a mechanical impact such as dropping or carrying, the split cores 41, 42, and 43 may be broken and damaged at the joint surfaces 411 and 412 of the split core 41, the joint surface 421 of the split core 42, and the joint surface 431 of the split core 43, which are not bonded but are in contact with each other. In the current sensor 10, the three engaging projections 228a and 228b are engaged with the engaging portion 212 as described above, so that relative displacement between the case 21 and the case 22 is restricted, and the two are integrated and fixed to each other, thereby preventing relative displacement of the divided cores 41, 42, and 43 and preventing the divided cores 41, 42, and 43 from being broken.

In the present embodiment, the joint surfaces are joined by bringing the joint surfaces into contact with each other without bonding, but the joint surfaces may be bonded to each other with a magnetic adhesive or may be welded to each other. Even after bonding or after welding, the bonding surfaces before bonding or before welding can be identified by analyzing the bonding trace or the welding trace. Further, if the joint surfaces are simply brought into contact with each other, the core can be easily disassembled by separating the split cores, and for example, workability in maintenance can be improved.

[ Effect and the like ]

As described above, the current sensor 10 of the present embodiment includes the core 40 through which the power supply conductor W passes and the coil 60 disposed so as to be wound around the core 40. The core 40 has a C-shape having a gap S locally by joining a plurality of split cores 41, 42, 43. The pair of joint surfaces 411, 412, 421, 431 (specifically, the pair of joint surface 411 and joint surface 421, and the pair of joint surface 412 and joint surface 431) of the plurality of split cores 41, 42, 43 is parallel to the opposing direction DX in which the other end surfaces 422, 432 as the pair of end surfaces of the core 40 forming the gap S oppose each other.

The inventors of the present invention have conducted extensive studies to find that: by providing a gap S that is extremely larger than the boundary portion of the plurality of divided cores 41, 42, 43 in a part of the core 40, the boundary portion can be ignored. Fig. 7 is a graph showing a BH curve of ferrite as an example of the material of the core 40 of the embodiment.

Here, a core of the comparative example without the gap S was prepared. The core of the comparative example has the same structure as the core 40 of the present embodiment except that the gap S is not provided. The magnetic flux density of the core of the comparative example had a value L21 in the range of 455mT to 465 mT. In this range, the BH curve changes in a curved manner, and the slope of a tangent L22 to the BH curve is small. Therefore, in the core of the comparative example, there is a possibility that the magnetic saturation occurs when the magnetic flux density is about 0.5T.

On the other hand, the magnetic flux density of the core 40 having the gap S of the present embodiment is a value L23 in the range of 180mT to 190 mT. Therefore, in the core 40, the magnetic flux density changes in the region R1 where the BH curve is a straight line and has a large slope. This can suppress the occurrence of magnetic saturation in the core 40.

Fig. 8 is an explanatory diagram comparing the output V40 of the core 40 of the embodiment with the output V1 of the core of the comparative example. The waveforms of the outputs V40 and V1 are waveforms obtained when a sinusoidal current (amplitude 15A, frequency 5kHz) flows through the electric conductor W. As shown in fig. 8, the peak of the waveform is largely distorted in the output of the core of the comparative example. The reason for this is that magnetic saturation occurs. On the other hand, in the output V40 of the core 40 of the embodiment, the peak of the waveform is not distorted. That is, it can be seen that: in the core 40 of the embodiment, magnetic saturation is suppressed as compared with the core of the comparative example.

In the current sensor 10 of the present embodiment, the pair of joint surfaces 411, 412, 421, 431 of the plurality of divided cores 41, 42, 43 forming the core 40 is parallel to the opposing direction DX of the pair of other end surfaces 422, 432 forming the gap S of the core 40. Thus, the interval LX in the opposing direction DX of the gap S can be adjusted by sliding the paired joint surfaces 411, 412, 421, 431 of the plurality of split cores 41, 42, 43 relative to each other.

Fig. 9 is a graph showing a relationship between the gap S of the core 40 and the output V40 of the current sensor 10 according to the embodiment. As shown in fig. 9, the sensitivity tends to decrease when the interval LX of the gap S is large, but the decrease in sensitivity is saturated when the interval becomes larger than a certain level. That is, only by adjusting the interval LX of the gap S, a desired sensitivity characteristic can be realized without being affected by a slight gap at the boundary portion of the plurality of divided cores 41, 42, 43.

As described above, the current sensor 10 of the present embodiment can achieve a desired sensitivity characteristic even if the core 40 has a boundary portion.

Further, even in the same core 40, if the interval LX of the gap S is adjusted, various sensitivity characteristics can be obtained, and thus components of other types of current sensors can be shared.

There are cases where: since the gap S is adjusted, at least one of the split cores 42 and 43 and the split core 41 are arranged in a staggered manner with a step therebetween. Fig. 10A and 10B are explanatory views showing a state in which at least one of the split cores 42 and 43 of the core 40 of the embodiment is arranged offset from the split core 41 with a step therebetween. Specifically, in fig. 10A, both the split cores 42 and 43 are offset in the width direction X with respect to the split core 41. In fig. 10B, both the split core 42 and the split core 43 are offset from the split core 41 in the thickness direction Y. The present inventors changed the offset amounts of both split core 42 and split core 43 with respect to split core 41, and found current-output lines at the respective offset amounts. Fig. 11 shows current-output lines at respective offsets of the core 40 of the present embodiment. Here, an output V41 in the case where the core 40 is not offset, an output V42 in the case where both the split core 42 and the split core 43 are offset by 0.5mm in the width direction X with respect to the split core 41, and an output V43 in the case where both the split core 42 and the split core 43 are offset by 1.0mm in the width direction X with respect to the split core 41 are shown. Fig. 11 also shows an output V44 in the case where both the split core 42 and the split core 43 are shifted by 0.5mm in the thickness direction Y with respect to the split core 41, and an output V45 in the case where both the split core 42 and the split core 43 are shifted by 1.0mm in the thickness direction Y with respect to the split core 41. In either case, the current-output lines are substantially the same, as shown in fig. 11. That is, even if at least one of the split cores 42 and 43 and the split core 41 are arranged in a staggered manner with a step due to the adjustment of the gap S, the sensitivity characteristics of the current sensor 10 are not affected.

The interval LX of the gap S may be determined based on various parameters of the core 40. The parameters that are criteria for determining the interval LX of the gap S include, for example, the number of turns of the electric conductor W, the cross-sectional area of the electric conductor W, the shape of the core 40, the distance from the electric conductor W to the core 40, and the material of the core 40. Examples of the material of the core 40 other than the ferrite include Ni-Zn based, Mn-Zn based, and iron based materials.

The number of the plurality of split cores 41, 42, 43 is 3 or more, and the pair of joint surfaces 411, 412, 421, 431 of each pair of split cores is parallel to the opposing direction DX.

Since the number of the plurality of split cores 41, 42, 43 is 3 or more, the inside of the C-shaped core 40 can be opened to a large extent at the time of assembly. Therefore, the electric conductor W can be easily arranged in the C-shaped core 40.

Further, since the pair of joint surfaces 411, 412, 421, 431 of each pair of split cores (the pair of split core 41 and split core 42, and the pair of split core 41 and split core 43) is parallel to the opposing direction DX, in any pair of split cores, the interval LX of the gap S can be adjusted by sliding the pair of joint surfaces 411, 412, 421, 431 each other.

The current sensor 10 also has a non-magnetic bobbin 50 around which a coil 60 is wound. The bobbin 50 is provided so as to fit the pair of end faces (the other end faces 422 and 432) of the core 40 and surround the gap S.

Thus, the pair of end faces of the core 40 are locked by the non-magnetic bobbin 50 around which the coil 60 is wound, and therefore the adjusted gap S can be stably maintained. That is, a dedicated member for maintaining the interval LX of the gap S is not required, and an increase in the number of components can be suppressed. Further, since the bobbin 50 is a non-magnetic body, it does not affect the current detection.

Here, when the coil 60 is directly wound around the core 40 so as to surround the gap S, the winding operation becomes difficult because of the gap S. However, by winding the coil 60 around the non-magnetic bobbin 50, the gap S is surrounded by the bobbin 50, and workability can be improved.

The current sensor 10 includes a case 21 that houses one of the plurality of divided cores 41, 42, and 43, and a case 22 that houses one or more other divided cores 42 and 43 of the plurality of divided cores 41, 42, and 43. By integrating the case 21 and the case 22, one split core 41 is fixed to the other split cores 42 and 43.

Thus, the plurality of split cores 41, 42, and 43 are less likely to be displaced from each other after assembly in the case 21 and the case 22. Therefore, the interval LX of the gap S of the core 40 is stabilized for a long period of time, and thus the sensitivity characteristics of the current sensor 10 can be maintained for a long period of time.

Further, the core 40 is formed by joining a plurality of divided cores 41, 42, 43.

Thus, at the time of assembly, the plurality of divided cores 41, 42, 43 are assembled so as to surround the electric conductor W to form the core 40, whereby the electric conductor W can be easily arranged to penetrate through the C-shaped core 40.

[ modified examples ]

The core structure is not limited to the structure described in the above embodiment. Therefore, a modification of the core will be described below centering on differences from the above embodiment. In the following description, the same reference numerals are given to the same portions as those of the above-described embodiment, and the description thereof may be omitted.

(modification 1)

In the above embodiment, the current sensor 10 includes the core 40 including the 3 divided cores 41, 42, and 43. The current sensor of modification 1 includes a core 40A including two divided cores 44 and 45. Fig. 12 is a plan view of a core 40A of modification 1. Fig. 12 corresponds to fig. 6.

As shown in fig. 12, the core 40A is composed of two split cores 44 and 45. A gap Sa is provided in a lower portion of the rectangular frame-shaped split core 44 in the direction of the positive X-axis. One tip surface 441 of the pair of tip surfaces 441 and 442 of the split core 44 faces in the direction of the positive side of the X axis, and the other tip surface 442 faces downward, i.e., in the direction of the negative side of the Z axis. One top end face 441 is a plane parallel to the YZ plane. The other tip face 442 is a plane parallel to the XY plane. One tip end surface 441 is a joint surface to which the other divided core 45 is joined.

The split core 45 has a substantially L-shape. One end surface 451 of the segment core 45 is a joint surface to be joined to the tip end surface 441 of the segment core 44. One end surface 451 of the divided core 45 is a plane parallel to the YZ plane. One end surface 451 of the split core 45 is joined to the distal end surface 441 of the split core 44 in a posture in which the other end surface 452 of the split core 45 faces upward. The other end surface 452 of the segment core 45 is a plane parallel to the XY plane.

A gap Sa is formed between the distal end surface 442 of the split core 44 and the other end surface 452 of the split core 45. The pair of end surfaces (the distal end surface 442 and the other end surface 452) forming the gap Sa face each other in the Z-axis opposing direction DZ with the gap Sa therebetween. By adjusting the interval LZ (length in the Z-axis direction) of the gap Sa in advance before assembly, a desired sensitivity characteristic can be realized. As described above, both the distal end surface 441 of the split core 44 and the one end surface 451 of the split core 45 are planes parallel to the YZ plane. Therefore, by sliding the joint surfaces (the distal end surface 441 and the one end surface 451) of the split cores 44 and 45 with each other to move the split core 45, the position of the other end surface 452 of the split core 45 can be adjusted in the Z-axis direction, and the interval LZ of the gap Sa can be adjusted.

In addition, in the core 40A of modification 1, the coil 60 is wound around the upper portion of the split core 45. The coil 60 may be wound directly on the upper portion of the divided core 45 or may be wound indirectly on the upper portion of the divided core 45 via a bobbin.

(modification 2)

In the above embodiment, the current sensor 10 includes the core 40 having the gap S at the center of the upper frame portion in the frame shape. The current sensor of modification 2 includes a core 40B having a gap Sb provided at the center of a lower frame portion of a frame shape. Fig. 13 is a plan view of a core 40B according to modification 2. Fig. 13 corresponds to fig. 6.

The core 40B has a gap Sb located at the center of the rectangular frame-shaped lower frame portion in a plan view, and has a C-shape. Specifically, the core 40B has a structure in which the core 40 is turned upside down, and is the same structure as the core 40. In the core 40B of modification 2, the coil 60 is wound around the upper portion of the split core 41. The coil 60 may be wound directly on the upper portion of the divided core 41, or may be wound indirectly on the upper portion of the divided core 41 via a bobbin.

[ position of coil ]

In the current sensor 10, there are cases where: outside the core 40 there is a further electrical conductor different from the electrical conductor W. The accuracy of the current detection for the electrical conductor W may be degraded due to the presence of other electrical conductors. However, by disposing the coil 60 at an appropriate position with respect to the core 40, the influence of other electric conductors can be suppressed, and the accuracy of current detection with respect to the electric conductor W can be improved.

Fig. 14A is an explanatory diagram illustrating an influence of other electrical conductors W2, W3, W4, W5 on the core 40A of modification 1. Fig. 14B is an explanatory diagram illustrating the influence of other electrical conductors W2, W3, W4, W5 on the core 40B of modification 2. Fig. 14C is an explanatory diagram showing the influence of other electrical conductors W2, W3, W4, W5 on the core 40 of the embodiment. As shown in fig. 14A to 14C, another electric conductor W2 is disposed above the cores 40, 40A, and 40B. The other electrical conductor W3 is arranged in the direction of the X axis positive side of the cores 40, 40A, 40B. The other electrical conductor W4 is disposed below the cores 40, 40A, and 40B. The other electrical conductor W5 is arranged in the negative direction of the X axis of the cores 40, 40A, 40B.

Each of the graphs shown in fig. 14A to 14C shows the influence of the other electrical conductors W2 to W5 on the detection of the current flowing through the electrical conductor W when the gaps S, Sa, Sb are varied within the range of 0mm to 3 mm. In modification 2 and the embodiment, the influence of the other electrical conductor W5 is the same as the influence of the other electrical conductor W3, and therefore is omitted. A sensor output greater than-20 dB indicates that the effect of the other electrical conductors is significant.

In modification 1, it is understood that: in the case of the electric conductors W2 to W4 other than the other electric conductor W5, the sensor output is greater than-20 dB, affecting the detection of the current of the electric conductor W. In modification 2, it is understood that: in the case of the electrical conductors W2, W4 other than the other electrical conductor W3, the sensor output is greater than-20 dB, affecting the detection of the current of the electrical conductor W. These influences are assumed to be caused by magnetic fluxes from the external electrical conductors W2 to W5 entering the gaps Sa and Sb.

On the other hand, in the embodiment, it is known that: in the case of the other electrical conductors W2 to W4, the output was all-20 dB or less, and the fluctuation was small. This is because the coil 60 is wound around the position of the gap S surrounding the core 40, and therefore the coil 60 blocks the magnetic flux from the external electrical conductors W2 to W5 toward the gap S, and the influence of the magnetic flux can be suppressed. That is, the core 40 of the embodiment is preferable in terms of suppressing the influence from the other electrical conductors W2 to W5.

Next, the influence of the other electric conductors W2, W3, W4, and W5 in the case where the coil 60 was disposed at different positions of the cores 40, 40A, and 40B in modifications 1 and 2 and embodiments was examined.

Fig. 15 to 17 are explanatory diagrams showing the states of the cores 40, 40A, and 40B in each verification case and the sensor outputs in each verification case. The influence of the other electrical conductors W2 to W4 on the detection of the current flowing in the electrical conductor W is shown by the sensor output in each case of verification. In the graph showing the sensor output, a smaller output (longer bar graph) indicates a smaller influence on the detection of the current of the electric conductor W.

As shown in fig. 15, in case a, a coil 60 is wound around the upper portion of the core 40B of modification 2. In case B, the coil 60 is wound around the upper portion of the core 40 of the embodiment. In case C, the coil 60 is wound around the upper portion of the core 40A of modification 1. That is, in case A, C, the entire gaps Sa, Sb are exposed from the coil 60, but in case B, the entire gap S is covered by the coil 60.

As shown in fig. 15, it can be seen that: in case B, the influence of any of the other electrical conductors W2, W3, and W4 is smaller than in case A, C.

As shown in fig. 16, in case D, a coil 60 is wound around the lower portion of the core 40B of modification 2. In case E, the coil 60 is wound around the lower portion of the core 40 of the embodiment. In case F, the coil 60 is wound around the lower portion of the core 40A of modification 1. That is, in case E, F, the entire gap S, Sb is exposed from the coil 60, but in case D, the entire gap Sa is covered by the coil 60.

As shown in fig. 16, in case D, the influence of the other electrical conductor W3 is larger than that in case E, but the influence of the other electrical conductors W2 and W4 is smaller. Further, it can be seen that: in case D, all the other electrical conductors W2, W3, W4 have smaller influence than in case F. It can be said that the other electrical conductors W2, W3, W4 have a smaller influence in case D than in case E, F as a whole.

As shown in fig. 17, in case G, a coil 60 is wound around the center portion of the core 40B of modification 2 on the X-axis positive side. In case H, the coil 60 is wound around the center portion of the core 40 on the X axis positive side in the embodiment. In case I, the coil 60 is wound around the center portion of the core 40A of modification 1 on the X-axis positive side. That is, in case G, H, the gap S, Sa is entirely exposed from the coil 60, but in case I, the gap Sb is entirely covered by the coil 60.

As shown in fig. 17, it can be seen that: in case I, the influence of any of the other electrical conductors W2, W3, and W4 is smaller than in case G, H.

Attention is directed to B, E, H in connection with the core 40 of the embodiment. In the case B in which the gap S is surrounded by the coil 60, the influence of the other electrical conductor W3 is larger than that in the case E, but the influence of the other electrical conductors W2 and W4 is smaller. Further, it can be seen that: in case B, the influence of all the other electrical conductors W2, W3, W4 is smaller than in case H. It can be said that the other electrical conductors W2, W3, W4 have less influence in the case B than in the case E, H as a whole.

Attention is paid to A, D, G relating to the core 40A of modification 1. Therefore, the following steps are carried out: in case D in which the gap Sa is surrounded by the coil 60, the influence of any of the other electrical conductors W2, W3, and W4 is smaller than that in case A, G.

Note that C, F, I related to the core 40B of modification 2 is focused. In case I in which the gap Sb is surrounded by the coil 60, the influence of the other electrical conductor W3 is larger than in case C, but the influence of the other electrical conductors W2 and W4 is smaller. Further, it can be seen that: in case I, the influence of all the other electrical conductors W2, W3, W4 is smaller than in case F. It can be said that the influence of the other electrical conductors W2, W3, W4 is smaller in case I as compared with case C, F as a whole.

In this way, the current sensor 10 includes the cores 40(40B ) through which the power supply conductor W passes and the coil 60 disposed so as to be wound around the cores 40(40A, 40B). The core 40(40A, 40B) has a C-shape having gaps S, Sa, Sb in part. The coil 60 is wound around the space S (Sa, Sb).

Since the coil 60 is wound around the position of the gap S (Sa, Sb) surrounding the core 40(40A, 40B), the coil 60 blocks the magnetic flux from the external electrical conductors W2 to W5 toward the gap S (Sa, Sb), and the influence of the magnetic flux, that is, the influence of external noise can be suppressed.

The pair of end surfaces (the other end surfaces 422 and 432, the distal end surface 442, and the other end surface 452) of the core 40(40A and 40B) forming the gap S (Sa and Sb) are disposed in the coil 60.

Thereby, both end portions of the gap S (Sa, Sb) are covered with the coil 60. This allows the coil 60 to more reliably block the magnetic flux from the external electrical conductors W2 to W5 toward the gaps S (Sa, Sb). Therefore, the influence of the magnetic flux from the external electrical conductors W2 to W5 can be more reliably suppressed.

[ other embodiments ]

Fig. 18 is a perspective view of another current sensor 510 of an embodiment. Fig. 19 is a cross-sectional view of the current sensor 510 shown in fig. 18 at line XIX-XIX. Fig. 20 is a cross-sectional view of the current sensor 510 shown in fig. 18 at line XX-XX. In fig. 18 to 20, substantially the same parts as those of the current sensor 10 shown in fig. 1 to 5 are denoted by the same reference numerals. The current sensor 510 includes a housing 520 and a sensor unit 530 received in the housing 520.

Fig. 21 is a perspective view of the housing 520. In fig. 21, substantially the same portions as those of the case of the current sensor 10 shown in fig. 1 and 2 are denoted by the same reference numerals. The housing 520 includes two housings 21 and 22 divided in the Z-axis direction, and a hinge 551 for connecting the housing 21 to the housing 22. In detail, the hinge 551 connects one of the pair of lower wall portions 214 of the body portion 211 of the housing 21 to one of the pair of upper wall portions 224 of the body portion 221 of the housing 22.

The housing 21 includes: a main body portion 211 having a space 21s opened in the direction of the positive side of the Z axis and having a box shape; and a locking portion 212 locked to the case 22. The locking portion 212 is located on the opposite side of the hinge 551. Specifically, the locking portion 212 is provided on the other of the pair of lower wall portions 214 of the body portion 211 of the housing 21. A split core 41 as a part of the sensor unit 530 is fitted and fixed between the inner wall portions 215.

The housing 22 has a space 22s opened in the direction of the negative side of the Z axis, and has a box shape. The housing 22 has a pair of upper wall portions 223 opposing each other in the Y-axis direction, a pair of upper wall portions 224 opposing each other in the X-axis direction, and a bottom plate portion 229. The upper wall portions 223, 224 are connected to each other and extend from the bottom plate portion 229 to the negative side of the Z axis. The upper wall portions 223, 224 and the bottom plate portion 229 surround the space 22 s.

An engagement projection 228a is provided on the outer side surface of the other of the pair of upper wall portions 224 of the case 22.

The locking portion 212 of the housing 21 extends from the outer surface of the lower wall portion 214 in the direction of the Z-axis positive side. The locking portion 212 has a substantially U-shape. By rotating the housing 21 relative to the housing 22 about the hinge 551, the engagement portion 212 is engaged with the engagement projection 228a of the housing 22, and the housing 21 and the housing 22 are integrated and fixed to each other.

In the current sensor 10 shown in fig. 3, the split cores 42 and 43 are firmly fixed to the bobbin 50 so as to abut against the inner bottom portion 53 of the bobbin 50 and to be pressed into the space 50s of the bobbin body 51. In the current sensor 510, as shown in fig. 19, the split cores 42 and 43 abut against the inner bottom portion 53, but are accommodated in the space 50s with a gap 50t from the bobbin body 51. In this way, the split cores 42 and 43 are not fixed to the bobbin 50 before being housed in the case 22, but the split core 42, the split core 43, and the bobbin 50 are positioned and firmly fixed to the case 22, respectively, in order to maintain the shape of the sensor unit 530.

As shown in fig. 18 to 20, in the current sensor 510, an inner cover 531 covering the bobbin 50 is provided in an opening of the case 22. The inner cover 531 prevents a foreign substance having conductivity or magnetism from entering the case 22, protects the coil 60, and prevents the detection accuracy of the current sensor 530 from being affected.

In the current sensor 510, as shown in fig. 19 and 21, the case 22 has a rib 610, and the rib 610 protrudes from the main body portion 221 toward the space 22s for positioning the divided core 41 (42). The split cores 41, 42 are positioned with respect to the case 22 and the bobbin 50 by the ribs 610. In the assembly process of the current sensor 510, the bobbin 50 and the split cores 41 and 42 inserted into the space 50s of the bobbin 50 are press-fitted into the case 22, whereby the split core 42, the split core 43, and the bobbin 50 are positioned and firmly fixed to the case 22, respectively. At the time of insertion, there is a risk that: the split cores 41, 42 scrape the housing 22 to generate debris, which is sandwiched between the opposing face 612a of the rib 610 and the split core 41 (42). If debris is generated and is sandwiched between the opposing face 612a of the rib 610 and the partition core 41(42), there is a concern that: the divided cores 41 and 42 are displaced from the ribs 610 and cannot maintain the shape of the core 40, or the locking portions 212 of the housing 21 cannot reach the engaging projections 228a of the housing 22 and cannot be engaged with each other.

In the current sensor 510, in order to eliminate the above-described risk, the rib 610 has a base portion 611 protruding from the body portion 221 toward the space 22s, and a positioning portion 612 extending from the base portion 611 toward the split core 41 (42). The positioning portion 612 has an opposing surface 612a that is in opposing contact with the split core 41 (42). The positioning portion 612 is separated from the main body portion 221 via a slit 613 extending from the opposing surface 612 a. According to this structure, the debris generated when the split cores 41, 42 are inserted into the housing 22 moves through the slit 613, and therefore the debris is prevented from remaining between the opposing surface 612a of the rib 610 and the split core 41 (42).

In the current sensor 510, the case 21 has the protrusions 230a and 230b, and the protrusions 230a and 230b are configured to be fitted into the space 22s so as to be in contact with the body portion 221 of the case 22 when the case 21 and the case 22 are integrated. The protrusion 230a does not have the hinge portion 551 of the housing 21, but protrudes from the lower wall portion 214 on the opposite side of the hinge portion 551. The protrusion 230b extends from the bottom plate 219 of the housing 21. When the case 21 and the case 22 are integrated, the protrusions 230a and 230b contact the upper wall 223 of the body 221 of the case 22. This prevents the housings 21 and 22 from being displaced relative to each other, and in particular, the housings 21 and 22 are rotated in opposite directions relative to each other about the hinge 551. According to this configuration, as in the case of the current sensor 10, even if mechanical impact such as dropping or transportation is applied, the housings 21 and 22 are integrated and fixed to each other, and as a result, relative displacement of the split cores 41, 42, and 43 is prevented, and the split cores 41, 42, and 43 are prevented from being broken.

Fig. 23 is an enlarged sectional view of the current sensor 510 shown in fig. 19. The current sensor 510 preferably further includes a buffer 541, and the buffer 541 is provided between the body portion 211 of the case 21 and the division core 41. The cushion pad 541 is in contact with the lower wall portion 214 and the split core 41 particularly between the lower wall portion 214 and the split core 41 of the body portion 211. This enables the split core 41 to be reliably positioned and fixed to the case 21, and prevents the split cores 41, 42, and 43 from being broken.

Fig. 23 is a perspective view of another sensor unit 530 of the current sensor 510. In fig. 23, substantially the same portions as those of the sensor unit 30 shown in fig. 4 are denoted by the same reference numerals. When the case 21 and the case 22 are integrated, the joint surface 411 of the split core 41 is joined to the joint surface 421 of the split core 42, and the joint surface 412 of the split core 41 is joined to the joint surface 431 of the split core 43. Both ends 411a in the Y axis direction of the joint surface 411 of the divided core 41 are chamfered. One of the two ends 411a may not be chamfered. Both ends 412a in the Y axis direction of the joint surface 412 of the split core 41 are chamfered. One of the two ends 412a may not be chamfered. Thus, even if mechanical impact such as dropping or transportation is applied, the corners of the split cores 41, 42, 43 are prevented from directly contacting each other, and the split cores 41, 42, 43 are prevented from being broken.

Fig. 24 is a perspective view of yet another sensor unit 630 of the current sensor 510. In fig. 24, substantially the same portions as those of the sensor unit 530 shown in fig. 23 are denoted by the same reference numerals. Both ends 421a of the joint surface 421 of the split core 42 in the Y axis direction are chamfered. One of the two ends 421a may not be chamfered. Both ends 431a of the joint surface 431 of the split core 43 in the Y-axis direction are chamfered. One of the ends 431a may not be chamfered. Thus, even if mechanical impact such as dropping or transportation is applied, the corners of the split cores 41, 42, 43 are prevented from directly contacting each other, and the split cores 41, 42, 43 are prevented from being broken.

[ others ]

The current sensor of the present disclosure has been described above based on the above-described embodiment and modifications, but the present disclosure is not limited to the above-described embodiment and modifications.

In the above embodiment, the case where the number of divisions of the core is two or three is exemplified, but the number of divisions of the core may be four or more. In addition, if only the influence from the other electrical conductors W2 to W5 is considered to be suppressed, that is, if the adjustment of the interval LX of the gap S is not considered, the core may not be divided.

In addition, the present disclosure also includes an embodiment obtained by applying various modifications to the embodiment that can be conceived by those skilled in the art, and an embodiment obtained by arbitrarily combining the constituent elements and functions of the embodiment and the modifications within a range that does not depart from the gist of the present disclosure.

Description of the reference numerals

10. A current sensor; 20. a housing; 21. a housing (first housing); 22. a case (second case); 30. a sensor unit; 40. 40A, 40B, a core; 41. 42, 43, 44, 45, split core; 50. a bobbin; 51. a bobbin body; 52. a flange portion; 53. an inner bottom; 60. a coil; 211. a main body portion; 212. a card-holding section; 213. a lower wall portion; 213a, 215a, 223a, a notch; 214. a lower wall portion; 215. an inner wall portion; 221. a main body portion; 223. an upper wall portion; 224. an upper wall portion; 224a, a protrusion; 224b, a restricting convex portion; 228a, 228b, engaging projections; 411. 412, 421, 431, joint surface; 422. 432, 452, end faces; 441. 442, a tip end face; 451. an end face; 510. a current sensor; 520. a housing; 530. a sensor unit; 630. a sensor unit; w, an electrical conductor.