Electric current sensor

Abstract

The present invention discloses an electric current sensor that has excellent versatility and can be applied regardless of the range of the electric current to be measured.　An electric current sensor 10 comprises a conductor 14 through which an electric current flows, a magnetism collecting core 18 which is disposed at the periphery of the conductor 14 to collect and guide a magnetic field generated around the conductor 14, and which is provided with a gap portion 16 in a part through which guided magnetic field passes, and a magnetism detector 20 disposed in the gap portion 16, wherein the magnetism collecting core 18 is constituted by arranging a plurality of plate-shaped magnetic bodies 12.

Description

Current Sensor

[0001] The present disclosure relates to a current sensor.

[0002] Patent Literature 1 discloses a magnetic detection type current sensor mounted on vehicles such as electric vehicles and hybrid vehicles, which measures the value of the current flowing through the current path by detecting the amount of magnetic flux generated by the current flowing through the current path. To enable more accurate measurement of the current value, this current sensor includes a magnetic flux collecting core formed by cutting a portion of a round or rectangular wound core around the current path, and a Hall element, which is a magnetic detector, is placed in the gap. Magnetic flux in the linear region of the magnetic characteristics is input to the Hall element, enabling highly accurate detection.

[0003] JP 2013-113630 A

[0004] However, if a current sensor is intended for high-precision measurement in a large current range, it is necessary to miniaturize the magnetic core to increase its magnetic resistance and apply magnetic flux to the Hall element within the linear region of the magnetic characteristics. If a current sensor is intended for measurement of a minute current, it is necessary to enlarge the magnetic core to reduce its magnetic resistance and collect magnetic flux to an appropriate range. Therefore, it is necessary to provide magnetic cores with different magnetic resistances depending on the current range to be measured by the current sensor, which necessitates manufacturing a dedicated magnetic core for each current sensor, resulting in unavoidable high costs.

[0005] Therefore, a current sensor with excellent versatility that can be applied regardless of the current range to be measured is disclosed.

[0006] The current sensor of the present disclosure comprises a conductor through which a current flows, a magnetic collection core arranged around the conductor to collect and induce a magnetic field generated around the conductor and having a gap portion through which the induced magnetic field passes, and a magnetic detector arranged in the gap portion, wherein the magnetic collection core is formed by arranging a plurality of flat magnetic bodies.

[0007] According to the present disclosure, it is possible to provide a current sensor that is highly versatile and can be applied regardless of the current range to be measured.

[0008] FIG. 1 is a perspective view showing a state in which the current sensor according to the first embodiment is applied to a large current, and is a view showing the state in which it is mounted on a printed circuit board. FIG. 2 is a plan view of the current sensor shown in FIG. 1. FIG. 3 is a cross-sectional view taken along III-III in FIG. 2. FIG. 4 is a perspective view showing a specific example of a flat magnetic body constituting the current sensor shown in FIG. 1. FIG. 5 is a longitudinal cross-sectional view showing the current sensor shown in FIG. 1 housed in a case, and is a view corresponding to FIG. 3. FIG. 6 is a perspective view showing a state in which the current sensor according to the first embodiment is applied to a small current, and is a view showing the state in which it is mounted on a printed circuit board. FIG. 7 is a longitudinal cross-sectional view of the current sensor shown in FIG. 6, and is a view corresponding to FIG. 3. FIG. 8 is a longitudinal cross-sectional view showing another aspect of the magnetic core for small currents shown in FIG. 7.

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. A current sensor of the present disclosure includes: (1) a conductor through which a current flows, a magnetic field collecting core disposed around the conductor to collect and induce a magnetic field generated around the conductor and having a gap through which the induced magnetic field passes, and a magnetic detector disposed in the gap, wherein the magnetic field collecting core is configured by arranging a plurality of flat magnetic bodies.

[0010] According to the current sensor of the present disclosure, the magnetic flux collector core disposed around the conductor can be constructed by arranging multiple flat magnetic bodies. Therefore, by simply arranging multiple flat magnetic bodies to form a magnetic flux collector core with a shape that has optimal magnetic resistance depending on the current range measured by the current sensor, a current sensor having a magnetic flux collector core capable of measuring a desired current range can be provided. In other words, regardless of the current range measured by the current sensor, it is sufficient to simply prepare multiple flat magnetic bodies as components for the magnetic flux collector core, which is more versatile than conventional structures in which a dedicated magnetic flux collector core was manufactured for each current sensor. This makes it possible to provide a highly versatile current sensor that can be applied regardless of the current range measured.

[0011] (2) In the above (1), it is preferable that the plurality of flat magnetic bodies all have the same width and thickness. Since the width and thickness of each flat magnetic body are the same, it is easy to set the shape of the magnetic core having the optimal magnetic resistance for the current range to be measured and to arrange the plurality of flat magnetic bodies to achieve that shape, thereby improving workability.

[0012] (3) In the above (1) or (2), it is preferable that the plurality of flat magnetic bodies all have the same shape. Since the plurality of flat magnetic bodies have the same shape, it is easy to set the shape of the magnetic core having the optimal magnetic resistance for the current range to be measured and to arrange the plurality of flat magnetic bodies to achieve that shape, thereby improving workability. In addition, since it is sufficient to prepare multiple flat magnetic bodies of the same shape, it is also possible to reduce manufacturing costs and product management costs.

[0013] (4) In any one of (1) to (3) above, it is preferable that the magnetic flux collector includes a case that houses the magnetic flux collector, the conductor, and the magnetic detector, and that the magnetic flux collector is configured by arranging the flat magnetic bodies in a state in which each of the flat magnetic bodies is held by a plurality of holding portions provided in the case. The magnetic flux collector can be configured by simply holding the flat magnetic bodies in a plurality of holding portions provided in the case that houses the magnetic flux collector, the conductor, and the magnetic detector. Therefore, even if the magnetic flux collector is configured by a plurality of flat magnetic bodies, the handling and assembly of the magnetic flux collector are improved. Furthermore, since the flat magnetic bodies do not need to be fixed to each other, the manufacturing of the magnetic flux collector can be simplified. Note that the flat magnetic bodies adjacent in the arrangement direction do not necessarily need to abut each other; they may be arranged adjacent to each other with a gap dimension smaller than the gap.

[0014] <Details of the embodiment of the present disclosure> Specific examples of the current sensor of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0015] First Embodiment A current sensor 10 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 7 . The current sensor 10 is installed in a junction box (electrical connection box) or the like inside a battery pack installed in, for example, an electric vehicle or hybrid vehicle, and measures the current flowing through the junction box (JB). In particular, the current sensor 10 includes a plurality of flat magnetic bodies 12. By varying the arrangement of the flat magnetic bodies 12, it is possible to measure current values ​​in different current ranges. For example, in the first embodiment, FIGS. 1 to 3 and 5 show a current sensor 10a adapted for large currents, while FIGS. 6 and 7 show a current sensor 10b adapted for minute currents. Note that the current sensors 10a and 10b can be positioned in any orientation within the vehicle. However, in the following description, the upper side will be referred to as the upper side in FIG. 3 , the lower side as the lower side in FIG. 3 , the left side as the upper side in FIG. 2 , the right side as the lower side in FIG. 2 , the front side as the left side in FIG. 2 , and the rear side as the right side in FIG. 2 . Furthermore, in the case of multiple identical components, reference numerals may be assigned to only some of the components, and the reference numerals may be omitted for the other components.

[0016] <Current Sensor 10 (Large Current Current Sensor 10a and Low Current Current Sensor 10b)> First, the structure common to the large current sensor 10a and the low current sensor 10b will be described below. The current sensor 10 includes a bus bar 14 as a conductor through which a current flows, a magnetic flux collecting core 18 arranged around the bus bar 14 to collect and induce the magnetic field generated around the bus bar 14 and having a gap 16 in a portion through which the induced magnetic field passes, and a magnetic detector 20 arranged in the gap 16. The magnetic flux collecting core 18 is formed by arranging a plurality of flat magnetic bodies 12 in a predetermined shape.

[0017] <Flat Magnetic Material 12> Figure 4 shows a specific example of the flat magnetic material 12. Each flat magnetic material 12 is flat, i.e., approximately rectangular, and has a predetermined length A, width B, and thickness C. In other words, in the state shown in Figure 4, the pair of opposing faces 22, 22, which have the largest areas, are arranged facing each other in the vertical direction. The distance between these faces 22, 22 is the thickness C. Each face 22 is rectangular, with a pair of opposing long sides and a pair of opposing short sides perpendicular to the opposing direction of the long sides. The length of the long sides of each face 22 is the length A of the flat magnetic material 12, and the length of the short sides of each face 22 is the width B of the flat magnetic material 12. Note that the length, width, and thickness of the flat magnetic material 12 are not limited to the above-described embodiments. The length, width, and thickness may differ from the above depending on the orientation of the flat magnetic body 12. The flat magnetic body 12 includes a cubic shape having the same length A, width B, and thickness C.

[0018] The flat magnetic bodies 12 constituting the magnetic flux collecting core 18 may have different shapes as long as they are all flat. That is, the length dimension A, width dimension B, and thickness dimension C may be different among the plurality of flat magnetic bodies 12. It is preferable that the width dimension B and thickness dimension C of each flat magnetic body 12 are equal. Alternatively, it is preferable that at least two of the length dimension A, width dimension B, and thickness dimension C are equal among the plurality of flat magnetic bodies 12. In particular, it is more preferable that each flat magnetic body 12 has the same shape, with the same length dimension A, width dimension B, and thickness dimension C.

[0019] The material of each of the flat magnetic bodies 12 is not limited as long as it is a metal, but it is preferable that it be made of an inexpensive iron-based material. The iron-based material may be not only iron, but also an iron alloy containing other elements such as nickel, chromium, molybdenum, etc. The method for forming each of the flat magnetic bodies 12 is not limited, but they may be formed, for example, by pressing a metal plate.

[0020] <Busbar 14> The busbar 14 is disposed, for example, in a JB to form an electrical path, with both ends of the busbar 14 connected to electrical components in the JB, or one end of the busbar 14 exposed to the outside from the JB to be connected to an external electrical device, etc. The busbar 14 is formed, for example, from a metal such as copper (including copper alloy) that has excellent electrical conductivity. In the first embodiment, the busbar 14 has a substantially rectangular cross section and extends substantially straight in the front-to-rear direction.

[0021] <Magnetic detector 20> As described above, the magnetic detector 20 is disposed in the gap 16 in the magnetic flux collecting core 18. In the first embodiment, the magnetic detector 20 includes a printed circuit board 24 and a magnetic sensor 26 mounted on the upper surface of the printed circuit board 24. The magnetic sensor 26 in the magnetic detector 20 is disposed in the gap 16 in the magnetic flux collecting core 18 described above.

[0022] <Printed Circuit Board 24> The printed circuit board 24 extends horizontally. An electric circuit (not shown) is printed on the top surface of the printed circuit board 24. The electric circuit and the magnetic sensor 26 are electrically connected to each other, thereby mounting the magnetic sensor 26 on the printed circuit board 24. On both left and right sides of the mounting location of the magnetic sensor 26 on the printed circuit board 24, recesses 28 are formed penetrating the printed circuit board 24 in the thickness direction (up and down direction) to accommodate the flat magnetic bodies 12 (each vertically oriented flat magnetic body 12 b) that constitute the magnetic flux collecting core 18, as described below. In the first embodiment, each recess 28 is formed as a notch in the outer peripheral edge of the printed circuit board 24. Note that these recesses 28 do not necessarily have to be formed on the printed circuit board 24, and the flat magnetic bodies 12 (each vertically oriented flat magnetic body 12 b) may be positioned outward in the left and right direction from both left and right ends of the printed circuit board 24.

[0023] Specifically, the printed circuit board 24 is disposed above the bus bar 14 at a distance, and extends in the left-right direction as a whole. The printed circuit board 24 protrudes outward in the left-right direction beyond both left-right ends of the bus bar 14. The left recess 28 is provided at the left end of the printed circuit board 24, positioned to the left of the left end of the bus bar 14. The left recess 28 is formed as a notch at the left end of the printed circuit board 24, opening to the left and rear. As will be described later, the flat magnetic material 12b is disposed vertically in each recess 28, and the left recess 28 has a front-to-rear dimension greater than the plate width dimension B of the flat magnetic material 12 and a left-to-right dimension greater than the plate thickness dimension C of the flat magnetic material 12.

[0024] Similarly, the right recess 28 is provided in a left-right intermediate portion of the printed circuit board 24, to the right of the right end of the bus bar 14. The right recess 28 is formed in a notch shape that opens rearward in the left-right intermediate portion of the printed circuit board 24. The right recess 28 also has a front-to-rear dimension that is larger than the plate width dimension B of the flat plate-shaped magnetic material 12, and a left-to-right dimension that is larger than the plate thickness dimension C of the flat plate-shaped magnetic material 12. This makes it possible, for example, to move the printed circuit board 24 toward a pair of vertically oriented flat plate-shaped magnetic materials 12b, 12b that are arranged at predetermined positions and face each other in the left-to-right direction, and to place each flat plate-shaped magnetic material 12b in each recess 28 on both left and right sides.

[0025] It should be noted that a known printed circuit board can be used as the printed circuit board 24. That is, the printed circuit board 24 may be a flexible printed circuit board that is capable of flexibly deforming, or may be a rigid printed circuit board that has a certain degree of deformation rigidity.

[0026] <Magnetic Sensor 26> There are no limitations on the magnetic sensor 26, and any known magnetic sensor may be used as long as it is a magnetic field detection type. That is, the magnetic sensor 26 detects the current value by utilizing a magnetic field generated by a current flowing through the bus bar 14, and may be a cored or coreless sensor, and specifically, a Hall IC or the like may be used.

[0027] In embodiment 1, the magnetic sensor 26 is arranged in the center of the gap portion 16 in the magnetic flux collecting core 18 in the left-right direction, and in particular in embodiment 1, the magnetic sensor 26 is located in the center part of the bus bar 14 in the plate width direction (left-right direction).

[0028] The following describes the differences in structure between the large current sensor 10a and the small current sensor 10b. The large current sensor 10a and the small current sensor 10b differ in the shape of the magnetic flux collector core 18 formed by each of the flat magnetic bodies 12. That is, in the large current sensor 10a, the large current magnetic flux collector core 18a is formed by each of the flat magnetic bodies 12, and in the small current sensor 10b, the small current magnetic flux collector core 18b is formed by each of the flat magnetic bodies 12.

[0029] <Magnetic collector core 18 (large current magnetic collector core 18 a)> The large current sensor 10 a includes a pair of large current magnetic collector cores 18 a, 18 a spaced apart from each other in the left-right direction. The gap 16 between the large current magnetic collector cores 18 a in the left-right direction is the gap 16 in the magnetic collector core 18 (each large current magnetic collector core 18 a), and the magnetic sensor 26 of the magnetic detector 20 is disposed in this gap 16.

[0030] Each heavy-current magnetic flux collector core 18a extends toward one side and the other side in the width direction (left-right direction) of the bus bar 14, separated by the gap 16. The ends of the portions of each heavy-current magnetic flux collector core 18a extending toward one side and the other side in the left-right direction are positioned outward in the left-right direction from both left-right ends of the bus bar 14, and the ends of the portions of each heavy-current magnetic flux collector core 18a extending outward in the left-right direction are bent and extend downward. That is, as shown in Fig. 3, each heavy-current magnetic flux collector core 18a has a substantially L-shaped cross section.

[0031] As described above, each large-current magnetic collector core 18a is composed of a plurality of flat magnetic bodies 12. In the first embodiment, each large-current magnetic collector core 18a is composed of two flat magnetic bodies 12, and the large-current current sensor 10a includes four flat magnetic bodies 12. That is, in the first embodiment, each large-current magnetic collector core 18a, which is generally L-shaped as described above, is composed of a horizontally oriented flat magnetic body 12a extending in the horizontal direction (a direction perpendicular to the up-down direction) and a vertically oriented flat magnetic body 12b extending in the up-down direction. The upper end of the vertically oriented flat magnetic body 12b abuts against or is close to, with a small gap between, the outer left-right ends of the horizontally oriented flat magnetic body 12a, thereby forming each large-current magnetic collector core 18a having a generally L-shape. In particular, in embodiment 1, the four flat magnetic bodies 12a, 12b that make up each large current magnetic core 18a have the same shape, with the same length dimension A, plate width dimension B, and plate thickness dimension C.

[0032] Specifically, the horizontally oriented flat plate magnetic bodies 12a constituting the upper part of each large current magnetic collector core 18a are arranged with their longitudinal axes in the left-right direction, so that the left-right dimension of these horizontally oriented flat plate magnetic bodies 12a is length dimension A and their front-to-rear dimension is plate width dimension B. Furthermore, the vertically oriented flat plate magnetic bodies 12b constituting the lower part of each large current magnetic collector core 18a are arranged with their longitudinal axes in the up-down direction, so that the up-down dimension of these vertically oriented flat plate magnetic bodies 12b is length dimension A and their front-to-rear dimension is plate width dimension B.

[0033] In other words, a pair of vertically oriented flat magnetic bodies 12b, 12b extending in the vertical direction are arranged laterally outward from both lateral ends of the busbar 14, facing each other at a predetermined distance in the lateral direction. The outer lateral ends of the horizontally oriented flat magnetic bodies 12a are arranged in contact with or close to the upper ends of the vertically oriented flat magnetic bodies 12b. The horizontally oriented flat magnetic bodies 12a face each other at a predetermined distance D (see FIG. 3 ), and the gap between the horizontally oriented flat magnetic bodies 12a forms the gap 16 in the magnetic flux collector core 18 (large current magnetic flux collector core 18a). In the first embodiment, the inner lateral surface of the horizontally oriented flat magnetic body 12a is located laterally inward from both lateral ends of the busbar 14. That is, in a vertical projection, both left and right end portions of the bus bar 14 partially overlap the horizontally oriented flat plate-shaped magnetic body 12a in the left and right direction E (see FIG. 3).

[0034] In the first embodiment, the busbar 14 is disposed below and spaced apart from the lower surface of the printed circuit board 24, and the lower surface of the busbar 14 and the lower end surfaces of the vertically oriented flat plate-like magnetic bodies 12b are positioned at substantially the same vertical position. In other words, the lower end portions of the large current magnetic cores 18a (the lower end portions of the vertically oriented flat plate-like magnetic bodies 12b) do not bend inward in the left-right direction toward the busbar 14, for example, and the lower end of each large current magnetic core 18a is open, exposing the busbar 14 downward through lower openings 30 defined by the lower ends of the large current magnetic cores 18a. In other words, in the first embodiment, the lower portion of the busbar 14 is not covered by the large current magnetic cores 18a.

[0035] 5, the heavy current sensor 10a includes a case 32 that houses the magnetic flux collecting cores 18 (each heavy current magnetic flux collecting core 18a), the conductive bus bar 14, and the magnetic detector 20 (the printed circuit board 24 and the magnetic sensor 26). In the first embodiment, the case 32 has a split structure and includes an upper case 34, a lower case 36, and a middle case 38 disposed vertically between the upper case 34 and the lower case 36. The case 32 (the upper case 34, the lower case 36, and the middle case 38) is formed of, for example, an insulating synthetic resin.

[0036] The plurality of flat magnetic bodies 12a, 12b are arranged in a state where they are respectively held by a plurality of holders 40 provided in the case 32, thereby constituting the magnetic flux collecting core 18 (each large current magnetic flux collecting core 18a). Specifically, a lower holder 40a is formed in the middle case 38 of the case 32 to hold the vertically oriented flat magnetic bodies 12b that constitute each large current magnetic flux collecting core 18a. The lower holder 40a is formed with a size that allows it to hold the vertically oriented flat magnetic bodies 12b, and opens upward in the middle case 38.

[0037] In the first embodiment, a pair of large-current magnetic flux collecting cores 18a (i.e., a pair of vertically oriented flat magnetic bodies 12b) are provided, and therefore a pair of lower retaining portions 40a are provided in the middle case 38, spaced a predetermined distance apart in the left-right direction. The vertically oriented flat magnetic bodies 12b are inserted from above into the lower retaining portions 40a of the middle case 38, thereby assembling the lower portions of the vertically oriented flat magnetic bodies 12b to the middle case 38, and the upper portions of the vertically oriented flat magnetic bodies 12b protrude upward from the lower retaining portions 40a. The vertically oriented flat magnetic bodies 12b may be inserted into the lower retaining portions 40a in a substantially press-fit state to be fixed with almost no play, or may be assembled to the lower retaining portions 40a with a slight gap to allow slight displacement relative to the lower retaining portions 40a.

[0038] Additionally, the upper case 34 of the case 32 is formed with upper holding portions 40b that hold the horizontally oriented flat magnetic bodies 12a that constitute each of the large current magnetic collection cores 18a. The upper holding portions 40b are formed with a size that allows them to hold the horizontally oriented flat magnetic bodies 12a and are open downward in the upper case 34. In the first embodiment, a pair of large current magnetic collection cores 18a (i.e., a pair of horizontally oriented flat magnetic bodies 12a) is provided, and therefore a pair of upper holding portions 40b are provided in the upper case 34, spaced a predetermined distance apart in the left-right direction. The method for fixing the horizontally oriented flat magnetic bodies 12a to the upper holding portions 40b is not limited, and may be press-fitting, adhesive bonding, or the like. Alternatively, the upper case 34 may be formed as an integrally molded product including each of the horizontally oriented flat magnetic bodies 12a. As a result, when the horizontally oriented flat-plate magnetic bodies 12 a are fixed to the upper holding portions 40 b , 40 b , the horizontally oriented flat-plate magnetic bodies 12 a are exposed on the lower surface of the upper case 34 .

[0039] The middle case 38 also has busbar supports 42 that support the busbar 14. As described above, the busbar 14 is disposed between the vertically oriented flat magnetic bodies 12b in the left-right direction. Therefore, the busbar supports 42 are disposed between the left-right directions of the lower holders 40a in the middle case 38. Note that in FIG. 5 , the busbar 14 is supported by being sandwiched between the busbar supports 42 in the vertical direction. However, the busbar 14 can be assembled to the middle case 38 by, for example, inserting it into the busbar supports 42 from the front side (front side) or the back side (rear side) in the direction perpendicular to the plane of FIG. 5 (front-rear direction). Furthermore, the middle case 38 has portions for supporting the printed circuit board 24 on the front side or the back side in the direction perpendicular to the plane of FIG. 5 . By placing the printed circuit board 24 on these portions, the printed circuit board 24 can be supported on the middle case 38. A storage recess 44 that opens downward is formed on the underside of the upper case 34, and when the upper case 34 and the middle case 38 are assembled, the magnetic sensor 26 mounted on the printed circuit board 24 is accommodated within the storage recess 44.

[0040] As described above, the middle case 38 holding the vertically oriented flat magnetic bodies 12b and the upper case 34 holding the horizontally oriented flat magnetic bodies 12a are fixed to each other, thereby positioning the large-current magnetic flux collector cores 18a (the flat magnetic bodies 12a, 12b), the bus bar 14, and the magnetic detector 20 (the printed circuit board 24 and the magnetic sensor 26) in predetermined positions. That is, by fixing the middle case 38 and the upper case 34 to each other, the upper ends of the vertically oriented flat magnetic bodies 12b and the outer lateral ends of the horizontally oriented flat magnetic bodies 12a abut or are adjacent to each other, thereby forming the large-current magnetic flux collector cores 18a in a generally L-shape. Furthermore, the inner lateral portions of the horizontally oriented flat magnetic bodies 12a are placed on the printed circuit board 24. The method for fixing the upper case 34 and the middle case 38 is not limited, and known fixing methods such as press-fitting, bolt fixing, and locking engagement may be used. The middle case 38 and the lower case 36 can also be fixed in the same manner.

[0041] In the above-described heavy-current current sensor 10a, when a current flows from front to rear through the busbar 14, a clockwise magnetic path R (shown by a two-dot chain line in FIG. 3 ) is formed around the busbar 14 in the longitudinal cross section of FIG. Here, heavy-current magnetic flux collector cores 18a are disposed on both the left and right sides of the busbar 14, and magnetic flux is collected by each heavy-current magnetic flux collector core 18a, forming the magnetic path R in a ring shape along each heavy-current magnetic flux collector core 18a. In particular, in the first embodiment, the current sensor 10a is designed for heavy currents and is intended to detect magnetic fields in heavy-current regions. Therefore, when a heavy current, such as a short-circuit current, flows through the busbar 14, the ring-shaped magnetic path R can be stably formed even when each heavy-current magnetic flux collector core 18a has a relatively large opening (lower opening 30). This allows the magnetic sensor 26 disposed in the gap 16 of each heavy-current magnetic flux collector core 18a to detect a current value corresponding to the strength of the magnetic field.

[0042] The large current to which the large current sensor 10a is applied is not limited, but is, for example, a current value flowing through the bus bar 14 in the range of 100 A to 2000 A.

[0043] 6 and 7, the minute current magnetic flux collecting core 18b provided in the minute current sensor 10b is generally annular, and has a gap 16 formed in the upper part with a predetermined left-right dimension. The magnetic sensor 26 of the magnetic detector 20 is disposed in this gap 16.

[0044] In other words, the minute current magnetic flux collector core 18b has an upper portion extending toward one side and the other side of the bus bar 14 in the plate width direction across the gap portion 16, side portions disposed laterally outward from both left and right ends of the bus bar 14, and a lower portion covering the bus bar 14 from below. In other words, the minute current magnetic flux collector core 18b has a shape similar to that of the large current magnetic flux collector core 18a, except that it further has a lower portion covering the bus bar 14 from below. Therefore, the minute current magnetic flux collector core 18b does not have a lower opening 30 that exposes the bus bar 14 downward.

[0045] Here, the minute current magnetic flux collector core 18b is also composed of a plurality of flat magnetic bodies 12a, 12b. That is, the minute current magnetic flux collector core 18b includes horizontally oriented flat magnetic bodies 12a that constitute the upper portion, vertically oriented flat magnetic bodies 12b that constitute the side portions, and horizontally oriented flat magnetic bodies 12a that constitute the lower portion. In the first embodiment, the minute current magnetic flux collector core 18b is composed of nine flat magnetic bodies 12a, 12b, and some of the flat magnetic bodies 12a, 12b have different length dimensions A. In particular, in the first embodiment, the vertically oriented flat magnetic bodies 12b that constitute the side portions are arranged such that two flat magnetic bodies 12b are stacked in the left-right direction on each side of the bus bar 14. Therefore, in the minute current magnetic core 18b, the upper part is made up of two horizontally oriented flat plate-like magnetic bodies 12a, the side parts are made up of four vertically oriented flat plate-like magnetic bodies 12b, and the lower part is made up of three horizontally oriented flat plate-like magnetic bodies 12a. The other configurations are the same as those of each of the large current magnetic cores 18a described above.

[0046] Although not shown, the minute current magnetic flux collecting core 18b having the above-described shape can also be held by a case similar to the case 32 in the large current sensor 10a.

[0047] In the current sensor 10b for low currents described above, when a current flows through the busbar 14 from front to rear, a clockwise magnetic path R' (shown by a two-dot chain line in FIG. 7 ) is formed around the busbar 14 in the longitudinal cross section of FIG. 7 . The low current magnetic flux collector core 18b is disposed around the busbar 14, and magnetic flux is collected by the low current magnetic flux collector core 18b, forming the magnetic path R' in a ring shape along the low current magnetic flux collector core 18b. In particular, in the first embodiment, the current sensor 10b is designed for low currents and is intended to detect magnetic fields in the low current range. Therefore, by employing the low current magnetic flux collector core 18b having a substantially ring shape, the ring-shaped magnetic path R' can be stably formed even when the current flowing through the busbar 14 is relatively small. This allows the magnetic sensor 26 disposed in the gap 16 of the low current magnetic flux collector core 18b to detect a current value corresponding to the strength of the magnetic field.

[0048] The magnitude of the current value of the minute current to which the minute current sensor 10b is applied is not limited.

[0049] According to the current sensor 10 of the first embodiment having the above-described structure, the magnetic flux collector core 18 is formed by arranging a plurality of flat magnetic bodies 12 a, 12 b. That is, by arranging a plurality of flat magnetic bodies 12 a, 12 b in a predetermined shape, it is possible to form either the large current magnetic flux collector core 18 a or the small current magnetic flux collector core 18 b described above. That is, by preparing a plurality of flat magnetic bodies 12 a, 12 b and arranging them in a predetermined shape, it is possible to manufacture either the large current current sensor 10 a or the small current current sensor 10 b depending on the situation. This allows for cost reduction and improved manufacturing efficiency without requiring major design changes for use with large currents and small currents.

[0050] It is preferable that the plurality of flat magnetic bodies 12a, 12b all have the same plate width dimension B and plate thickness dimension C. In other words, the plurality of flat magnetic bodies 12a, 12b may include those with different length dimensions A, which improves the degree of freedom in the shape of the magnetic flux collector core 18 formed by combining the plurality of flat magnetic bodies 12a, 12b, and makes it easier to form the magnetic flux collector core 18 in a desired shape. In particular, the plurality of flat magnetic bodies 12a, 12b having the same plate width dimension B and plate thickness dimension C can be formed, for example, by forming a long flat magnetic body and then cutting this long flat magnetic body to any length. This eliminates the need to prepare multiple molds or the like when forming the plurality of flat magnetic bodies 12a, 12b, thereby further reducing costs and improving manufacturing efficiency.

[0051] It is also preferable that the plurality of flat magnetic bodies 12 a, 12 b have the same shape, which eliminates the need for multiple molds or the like when forming the plurality of flat magnetic bodies 12 a, 12 b, and also eliminates the need for the cutting work described above, thereby further reducing costs and improving manufacturing efficiency.

[0052] The current sensor 10 includes a case 32 that houses the magnetic flux collecting core 18, the bus bar 14, and the magnetic detector 20. In the first embodiment, the case 32 has a divided structure including an upper case 34, a lower case 36, and a middle case 38. Of the plurality of flat magnetic bodies 12a, 12b that constitute the magnetic flux collecting core 18, some of the flat magnetic bodies 12 (the horizontally oriented flat magnetic bodies 12a) are held in the upper case 34, and the remaining flat magnetic bodies 12 (the vertically oriented flat magnetic bodies 12b) are held in the middle case 38. The magnetic flux collecting core 18 is formed by assembling the upper case 34 and the middle case 38. In other words, when forming the magnetic flux collecting core 18, it is not necessary to fix the plurality of flat magnetic bodies 12a, 12b in a predetermined shape, and the magnetic flux collecting core 18 can be more easily formed in a desired shape.

[0053] <Modifications> Although the first embodiment has been described above in detail as a specific example of the present disclosure, the present disclosure is not limited to this specific description. Modifications, improvements, etc. within the scope of achieving the object of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiment are also included in the technical scope of the present disclosure.

[0054] (1) In the above embodiment, the magnetic flux collector 18, which is composed of multiple flat magnetic bodies 12a, 12b, is shown as the large current magnetic flux collector 18a used in the large current sensor 10a and the small current magnetic flux collector 18b used in the small current sensor 10b. However, these are merely examples, and an intermediate current magnetic flux collector capable of detecting current values ​​intermediate between these two may be provided. In this case, for example, the small current magnetic flux collector 18b in the above embodiment may have the central flat magnetic body 12a removed from the three horizontally oriented flat magnetic bodies 12a in the lower portion. That is, in the small current magnetic flux collector 18b shown in the above embodiment, a gap separate from the gap portion 16 in which the magnetic sensor 26 is provided may be provided to increase the magnetic resistance, thereby enabling detection of current values ​​in the intermediate range between small currents and large currents. In other words, the range of currents to be detected can be adjusted by increasing or decreasing the number of flat magnetic bodies. When detecting the current value in the intermediate region as described above, the number of flat magnetic bodies in the side portions may be reduced instead of or in addition to reducing the number of flat magnetic bodies in the lower portion of the magnetic core for minute currents.

[0055] Furthermore, for example, when increasing the number of flat magnetic bodies in a large-current magnetic core, the number of horizontally oriented flat magnetic bodies in the upper portion can be increased and stacked vertically. This allows the vertical dimension of the gap to be larger, allowing the magnetic sensor of the magnetic detector to be stably positioned between the gaps. That is, multiple flat magnetic bodies can be stacked to adjust the position in the vertical or horizontal directions, or the thickness C of some of the multiple flat magnetic bodies can be changed. This may change the magnetic resistance of the magnetic core. However, if a change in magnetic resistance is not desired, for example, a synthetic resin spacer of the same shape as the flat magnetic bodies can be stacked.

[0056] (2) In the above embodiment, a notched recess 28 was formed in the portion of the printed circuit board 24 where the magnetic flux collecting core 18 was inserted. However, this is not limited to this form, and the printed circuit board may have the shape of a through hole that penetrates the board in the thickness direction (vertical direction).

[0057] (3) In the above embodiment, the printed circuit board 24 and the bus bar 14 are disposed spaced apart in the vertical direction, but this is not limiting, and the printed circuit board and the bus bar may be disposed overlapping each other in the vertical direction. Even when the printed circuit board and the bus bar are disposed spaced apart in the vertical direction, a spacer may be disposed between the printed circuit board and the bus bar, and the printed circuit board and the bus bar may be disposed overlapping each other on the spacer.

[0058] (4) In the above embodiment, the bus bar 14, the magnetic flux collecting core 18, and the magnetic detector 20 are housed in the case 32. However, this case may be a case dedicated to the current sensor, or may be a case constituting a JB that houses the current sensor. While this case preferably has a split structure, it is not limited to the case consisting of an upper case, a lower case, and a middle case as in the above embodiment. Note that the above-described case is not essential for the current sensor according to the present disclosure.

[0059] (5) In the low-current current sensor 10b of the above embodiment, the flat magnetic bodies 12a, 12b all have the same width B and thickness C but different lengths A, and the lower portion of the low-current magnetic flux collector core 18b is composed of three horizontally oriented flat magnetic bodies 12a. However, this is not limited to this. For example, as shown in FIG. 8 , the low-current magnetic flux collector core may use horizontally oriented flat magnetic bodies 12a' with a longer length A'. Instead of using multiple horizontally oriented flat magnetic bodies 12a each with a relatively short length, a single horizontally oriented flat magnetic body 12a' with a long length A' may be used in combination to simplify the assembly process. Alternatively, the low-current magnetic flux collector core 18b of the above embodiment may use multiple flat magnetic bodies of the same shape, all with the same length A, width B, and thickness C.

[0060] 10 Current sensor 10a Current sensor for large current 10b Current sensor for small current 12 Flat magnetic body 12a Flat magnetic body oriented horizontally Flat magnetic body oriented horizontally with a longer length than 12a' 12b Flat magnetic body oriented vertically 14 Bus bar (conductor) 16 Gap portion 18 Magnetic flux collecting core 18a Magnetic flux collecting core for large current 18b Magnetic flux collecting core for small current 20 Magnetic detector 22 Largest surface of flat magnetic body 24 Printed circuit board 26 Magnetic sensor 28 Recess 30 Lower opening 32 Case 34 Upper case 36 Lower case 38 Middle case 40 Holding portion 40a Lower holding portion 40b Upper holding portion 42 Bus bar support portion 44 Housing recess R, R' Magnetic path

Claims

1. A current sensor comprising: a conductor through which a current flows; a magnetic field collecting core arranged around the conductor to collect and induce the magnetic field generated around the conductor, and having a gap through which the induced magnetic field passes; and a magnetic detector arranged in the gap, wherein the magnetic field collecting core is formed by arranging a plurality of flat magnetic bodies.

2. The current sensor according to claim 1, wherein the plurality of flat magnetic bodies all have the same plate width and plate thickness.

3. The current sensor according to claim 1, wherein the plurality of flat magnetic bodies all have the same shape.

4. A current sensor as described in any one of claims 1 to 3, including a case that houses the magnetic flux collecting core, the conductor, and the magnetic detector, wherein the magnetic flux collecting core is constituted by an arrangement of a plurality of the flat magnetic bodies that are respectively held by a plurality of holding portions provided in the case.

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