Current sensor

Abstract

This current sensor (1) is provided with: a bus bar (11) through which a current to be measured flows; a magnetic detection unit (12) capable of detecting a magnetic field generated when the current to be measured flows through the bus bar (11); a housing (13) that holds the bus bar (11); a first magnetic shield (14A) capable of suppressing disturbing magnetic field noise applied to the magnetic detection unit (12); and a substrate (15) in which the magnetic detection unit (12) is disposed on a surface on the X1 side in the X-axis direction and in which the bus bar (11), the magnetic detection unit (12), the substrate (15), and the first magnetic shield (14A) are disposed in this order from the X1 side, the current sensor (1) being provided with a spacer (16) that is provided between the housing (13) and the substrate (15) and separates the bus bar (11) from the magnetic detection unit (12) in the X-axis direction. The substrate (15) is provided with a protruding portion (151) protruding in a protruding direction formed by at least one of a Y-axis direction and a Z-axis direction from a position held by the spacer portion (16), so that it is possible to suppress the temperature of an electronic component such as a magnetic detection unit from becoming high due to heat generated from the bus bar, and to be suitable for measurement of a large current.

Description

Technical Field

[0001] The present invention relates to a current sensor that detects a magnetic field generated by a current to be measured flowing through a bus bar and measures a current value of the current to be measured based on the detected magnetic field. Background Art

[0002] In recent years, as the demand for decarbonization has increased, in order to reduce CO2 emissions when driving cars, the conversion from engines to electric motors, i.e., fuel-free vehicles / electrification (EV conversion), has progressed, and current sensors are used as current measuring devices for measuring the current supplied to a three-phase motor, etc.

[0003] As EV shifting affects large commercial vehicles such as trucks and buses, the motor capacity in hybrid vehicles and electric vehicles has also increased, and the measured current of the current sensor used for motor control has also increased. In addition, the opportunity for continuous driving under high load conditions has also increased, and the current that is continuously energized has increased. The busbar, which serves as the current path for the measured current, generates an amount of heat proportional to the square of the current. Therefore, there is the following problem: as the measured current that is continuously energized increases, the heat generated from the busbar increases, and electronic components such as the magnetic detection unit arranged near the busbar become hot.

[0004] Patent Document 1 describes a current sensor in which a heat dissipation concavo-convex portion is provided on an insulating material portion of a housing in order to suppress a decrease in detection accuracy of the current sensor due to high temperature.

[0005] Patent Document 2 describes a current sensor in which a magnetic detection unit is provided in a cover in which a shield is insert-molded for the purpose of miniaturization.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. WO2019 / 092912

[0009] Patent Document 2: International Publication No. WO2019 / 117169 Summary of the invention

[0010] Technical problem to be solved by the invention

[0011] In the current sensor described in Patent Document 1, the size of the product becomes larger due to the heat dissipation concavo-convex portion provided on the cover, which increases the manufacturing cost. In the current sensor described in Patent Document 2 in which a magnetic detection unit is provided in the cover, the temperature in the storage space becomes high temperature exceeding the heat-resistant temperature of the magnetic detection unit due to the heat generated by the bus bar, which may cause the measurement accuracy of the current sensor to decrease and the product life to shorten.

[0012] Therefore, an object of the present invention is to provide a current sensor whose electronic components such as a magnetic detection unit are not easily heated by heat from a bus bar and is suitable for measuring a large current. Another object of the present invention is to provide a current sensor that can be miniaturized without reducing measurement accuracy.

[0013] Means for solving technical problems

[0014] The present invention has the following configuration as a means for solving the above-mentioned technical problems.

[0015] A current sensor comprises: a bus bar through which a measured current flows; a magnetic detection unit capable of detecting a magnetic field generated when the measured current flows through the bus bar; a housing for holding the bus bar; a first magnetic shield capable of suppressing interference magnetic field noise applied to the magnetic detection unit; and a substrate, wherein when three directions orthogonal to each other are a first direction, a second direction, and a third direction, the magnetic detection unit is arranged on a surface on one side in the first direction, and in the current sensor, the bus bar, the magnetic detection unit, the substrate, and the first magnetic shield are arranged in order from one side in the first direction, the current sensor is characterized in that a spacer is provided between the housing and the substrate to separate the bus bar and the magnetic detection unit in the first direction, and the substrate has a protrusion that protrudes from a position held by the spacer in a protrusion direction consisting of at least one of the second direction and the third direction.

[0016] The substrate can release heat generated by the bus bar due to the current to be measured to the outside through the protruding portion of the substrate. Therefore, the temperature rise of the magnetic detection unit arranged on the substrate due to the heat generated by the bus bar can be reduced.

[0017] The spacer may also be provided integrally with the housing.

[0018] By forming the spacer integrally with the housing, the strength of the spacer is increased, and since the spacer can be formed simultaneously with the housing, the spacer can be manufactured efficiently.

[0019] The housing may include a main body on one side of the partition in the first direction, and the main body may include an extending portion extending from a portion where the partition is provided in a direction including the protruding direction.

[0020] The extending portion may include a facing portion overlapping the protruding portion and a protecting portion located outside an end portion of the protruding portion when viewed along the first direction.

[0021] The housing may include a guard portion extending from the protection portion to the other side in the first direction, and the guard portion is separated from the protrusion when viewed along the first direction.

[0022] According to the above configuration, the protruding portion can be protected by the extending portion and the guard portion, so that the risk of the protruding portion contacting an external obstacle and damaging the substrate when handling the current sensor can be reduced.

[0023] The distance from the protecting portion to the end of the guard portion in the first direction may be greater than a distance from the protecting portion to a surface of the substrate on which the first magnetic shield is installed and less than a distance from the protecting portion to an upper surface of the first magnetic shield.

[0024] According to the above configuration, the protruding portion can be protected by the guard portion without increasing the size of the current sensor in the first direction.

[0025] At least a portion of the guard portion may overlap with the protrusion when viewed along at least one of the second direction and the third direction.

[0026] According to the above configuration, the corners of the protruding portion can be covered by the guard portion, thereby preventing the protruding portion from contacting the outside.

[0027] The guard portion may be a plurality of plate-shaped bodies, and gaps may be provided between adjacent plate-shaped bodies.

[0028] According to the above configuration, the gap of the guard part can adjust the flow of air formed in the space surrounded by the guard part, the protrusion, the spacer, and the opposing part. Therefore, the shape of the guard part can achieve a balance between the protection of the protrusion and the cooling effect of the substrate.

[0029] The first magnetic shield may be held by the substrate, and a side surface of the first magnetic shield may be covered by a covering portion.

[0030] When the first magnetic shield is held on the substrate, the bottom surface (upper surface) and the side surface of the first magnetic shield opposite to the substrate are exposed to the outside. Usually, an insulating film is formed on the bottom surface, and the side surface is a fracture surface. Therefore, by providing a covering portion covering the side surface, rust can be suppressed from the fracture surface of the first magnetic shield.

[0031] The present invention may include a plurality of measurement phases each including the bus bar and the magnetic detection unit, and the first magnetic shield may be independently provided for each of the measurement phases.

[0032] According to the above configuration, the first magnetic shield is less likely to be magnetically saturated than when a large first magnetic shield is used for multiple measurement phases. Therefore, the first magnetic shield has a higher effect of suppressing disturbance magnetic field noise, and the measurement accuracy of the current sensor is improved.

[0033] The partition portion may include a communication portion opened in the second direction and / or the third direction.

[0034] According to the above configuration, the space provided between the substrate and the bus bar located inside the partition portion can be cooled efficiently.

[0035] The spacer may surround the magnetic detection unit when viewed along the first direction.

[0036] According to the above configuration, the magnetic detection unit can be protected from external influences by the spacer.

[0037] The current sensor may further include a second magnetic shield, wherein the second magnetic shield, the bus bar, the magnetic detection unit, the substrate, and the first magnetic shield are arranged in this order from one side in the first direction.

[0038] With the above configuration, the effect of suppressing noise caused by the disturbance magnetic field is enhanced, and the measurement accuracy of the current sensor is improved.

[0039] The distance between the first magnetic shield and the bus bar in the first direction may be greater than the distance between the second magnetic shield and the bus bar in the first direction, and the thickness of the first magnetic shield may be smaller than the thickness of the second magnetic shield.

[0040] By adjusting the thickness of each shield according to the distance from the bus bar, the thickness of the magnetic shield in the first direction can be reduced. Thus, the thickness of the magnetic shield can be suppressed, and the current sensor can be miniaturized.

[0041] Effects of the Invention

[0042] According to the present invention, the heat generated by the bus bar can be released to the outside from the protruding portion of the substrate, thereby reducing the temperature rise of the substrate and the magnetic detection unit. Therefore, a current sensor suitable for measuring large currents can be provided, which suppresses the temperature rise of electronic components such as the magnetic detection unit caused by the heat generated by the bus bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a perspective view of the current sensor according to the first embodiment.

[0044] Figure 2A yes Figure 1 Cross-sectional view of the current sensor at line AA.

[0045] Figure 2B yes Figure 1 Top view of the current sensor.

[0046] Figure 3 It is a cross-sectional view of a modified example of the current sensor of FIG. 2 .

[0047] Figure 4 It is a cross-sectional view of a current sensor according to a second embodiment.

[0048] Figure 5 yes Figure 4 Top view of the current sensor.

[0049] Figure 6 yes Figure 4 A top view of a modified example of the current sensor.

[0050] Figure 7 yes Figure 4 A top view of another modified example of the current sensor.

[0051] Figure 8 It is a cross-sectional view of a current sensor according to a third embodiment.

[0052] Fig. 9 yes Figure 8 A cross-sectional view of a modified example of the current sensor.

[0053] Fig.10 yes Figure 8 A cross-sectional view of another modified example of the current sensor.

[0054] Fig.11 It is a perspective view of a current sensor according to a fourth embodiment.

[0055] Fig.12 yes Fig.11 Cross-sectional view of the current sensor at line AA.

[0056] Fig.13 yes Fig.12 A cross-sectional view of a modified example of the current sensor.

[0057] Fig.14 It is a cross-sectional view of a current sensor according to a fifth embodiment.

[0058] Fig.15 is a cross-sectional view of a conventional current sensor.

[0059] Fig.16 is a cross-sectional view of a conventional current sensor. DETAILED DESCRIPTION

[0060] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the accompanying drawings, the same reference numerals are given to the same components, and descriptions thereof are omitted. In order to indicate the positional relationship of each component, reference coordinates are appropriately shown in each of the drawings. With respect to the reference coordinates, the vertical direction of the plate surface of the busbar is set as the X-axis direction (first direction), the direction orthogonal to the extension direction of the busbar in the plate surface of the busbar is set as the Y-axis direction (second direction), and the extension direction of the busbar is set as the Z-axis direction (third direction).

[0061] [First embodiment]

[0062] Figure 1 , Figure 2A as well as Figure 2B 1 are a perspective view, a cross-sectional view, and a plan view of the current sensor 1 according to the present embodiment. Figure 2A express Figure 1 The section of line AA in .

[0063] As shown in these figures, the current sensor 1 of the present embodiment includes a bus bar 11, a magnetic detection unit 12, a housing 13, a first magnetic shield 14A, and a substrate 15. The components are arranged in order from the X1 side (one side) toward the X2 side (the other side) in the X-axis direction (first direction), such as the bus bar 11, the magnetic detection unit 12, the substrate 15, and the first magnetic shield 14A.

[0064] The busbar 11 is a conductive material formed in a plate shape, through which the current to be measured of the detection object flows. The busbar 11 is provided so that two opposing plate surfaces correspond to the upper and lower sides (both sides in the X-axis direction) of the housing 13, and is made of, for example, copper, brass, aluminum, or the like.

[0065] The connection portion of the bus bar 11 connected to the outside in the Z-axis direction, i.e., the two ends, need not be linearly symmetrical with respect to the Z-axis. In addition, the portion of the bus bar 11 facing the magnetic detection unit 12 may be smaller in the Y-axis direction than other portions. Portions of the bus bar 11 other than the portion facing the magnetic detection unit 12 may not be in a flat plate shape, and may be bent, for example.

[0066] The magnetic detection unit 12 can detect the magnetic field generated when the measured current flows through the bus bar 11, is separated from the bus bar 11, and is arranged at a position opposite to the bus bar 11 in such a way that the sensitivity axis direction is orthogonal to the measured current direction flowing through the bus bar. Figure 2A as well as Figure 2BIn the figure, when observed along the X-axis, the center of the width of the magnetic detection unit 12 in the Y-axis direction is arranged to overlap with the center of the width of the busbar 11 in the Y-axis direction. However, the magnetic detection unit 12 only needs to be located at a position where the magnetic field generated when the measured current flows through the busbar 11 can be measured. Therefore, the entire magnetic detection unit 12 may not be arranged at a position overlapping with the busbar 11, but at a staggered position. However, when observed along the X-axis, it is preferred that a portion of the magnetic detection unit 12 overlaps with the opposing busbar 11. As the magnetic detection element of the magnetic detection unit 12, a magnetoresistive effect element, a Hall element, or the like can be used.

[0067] The case 13 holds the bus bar 11. In the current sensor 1, a part of the bus bar 11 is formed integrally with the case 13 by insert molding.

[0068] The first magnetic shield 14A is formed by stacking a plurality of metal plates of the same shape. The first magnetic shield 14A blocks the disturbance magnetic field noise, thereby reducing the disturbance magnetic field noise applied to the magnetic detector 12, thereby improving the resistance of the magnetic detector 12 to the disturbance magnetic field noise.

[0069] In the current sensor 1, the first magnetic shield 14A is provided on the surface on the X2 side (the other side) in the X-axis direction of the substrate 15. The first magnetic shield 14A provided on the X2 side can reduce the disturbance magnetic field noise, but a magnetic shield may also be provided on the X1 side of the bus bar 11. By setting the configuration in which the magnetic detection unit 12 and the bus bar 11 are arranged between a pair of flat plate-shaped magnetic shields, the disturbance magnetic field resistance of the magnetic detection unit 12 is further improved.

[0070] Fig.15 9 is a cross-sectional view showing the structure of a conventional current sensor 90. As shown in the figure, the first magnetic shield 14A of the current sensor 90 is formed integrally with the housing 93A, and the first magnetic shield 14A is separated from the substrate 15.

[0071] In contrast, as shown in FIG2 , the current sensor 1 has the first magnetic shield 14A on the surface on the X2 side of the substrate 15. Therefore, compared with the current sensor 90 in which the first magnetic shield 14A and the substrate 15 are separated, the current sensor 1 has a closer distance between the first magnetic shield 14A and the substrate, and can suppress the size in the height direction (X-axis direction) and achieve miniaturization. In addition, since the first magnetic shield 14A is located close to the magnetic detection unit 12, the shielding effect of the first magnetic shield 14A against the external magnetic field is improved, and the current sensor 1 is not easily affected by the external magnetic field, so the measurement accuracy of the current sensor 1 is improved.

[0072] In addition, in the conventional current sensor 90, the substrate 15 on which the magnetic detection unit 12 is mounted is arranged in the space sandwiched between the housing 93A and the housing 93B. Therefore, when a large current flows through the bus bar 11, the air in the above space may be heated to a temperature exceeding the upper limit temperature of the magnetic detection unit 12 due to the heat generated by the bus bar 11.

[0073] In contrast, in current sensor 1, since at least a portion of substrate 15 is exposed outside housing 13 formed of resin, heat can be easily released to the outside through substrate 15. Therefore, the temperature rise of the space where magnetic detector 12 is provided due to heat generated by busbar 11 can be suppressed.

[0074] In the current sensor 1, the surface of the other side (X2 side) of the bottom surface of the first magnetic shield 14A held on the substrate 15 is exposed to the outside. Therefore, even if a part of the substrate 15 is covered by the first magnetic shield 14A, the substrate 15 can release heat to the outside through the first magnetic shield 14A. Therefore, the temperature rise around the magnetic detection unit 12 caused by the heat of the bus bar 11 can be reduced. As the substrate 15, for example, epoxy glass or ceramics can be cited.

[0075] As methods for forming the first magnetic shielding member 14A on the substrate 15, for example, there are: a method of bonding the first magnetic shielding member 14A to the substrate 15; a method of overlapping the substrate 15 and the first magnetic shielding member 14A and heating and pressurizing them in a vacuum state (lamination pressing); a method of printing a paste having magnetic shielding properties on the substrate 15 to form the first magnetic shielding member 14A; a method of plating the first magnetic shielding member 14A and welding it to the substrate 15; a method of fastening the pins of the first magnetic shielding member 14A and welding it to the substrate 15, etc.

[0076] The current sensor 1 includes a spacer 16 between the housing 13 and the substrate 15. The spacer 16 separates the bus bar 11 and the magnetic detection unit 12 in the X-axis direction and separates the substrate 15 from the housing 13. In the current sensor 1, the spacer 16 is integrally provided with the housing 13, so that the spacer 16 with excellent strength can be efficiently manufactured. In addition, by integrally providing at least a portion of the spacer 16 with the housing 13, the manufacturing efficiency is improved, but the spacer 16 may also be constituted by a member different from the housing 13.

[0077] like Figure 2A , Figure 2B As shown in FIG. 1 , in the current sensor 1 , when viewed along the X-axis direction, the magnetic detection portion 12 is surrounded by the spacer 16 . Therefore, the magnetic detection portion 12 can be protected by the spacer 16 .

[0078] The substrate 15 includes a protrusion 151 that protrudes in a protrusion direction consisting of at least one of the Y-axis direction and the Z-axis direction from a position held by the spacer 16. In the present embodiment, the Y-axis direction (second direction) and the Z-axis direction (third direction) are two directions that are orthogonal to the X-axis direction (first direction) and are orthogonal to each other.

[0079] like Figure 2A As shown, in the case where there is a protrusion 151 in the Y-axis direction in the cross section of the current sensor 1 cut by the XY plane, the protrusion direction includes the Y-axis direction. In addition, in the case where there is a protrusion in the cross section of the current sensor 1 cut by the XZ plane (not shown), the protrusion direction includes the Z-axis direction. The protrusion direction of the protrusion 151 may be one of the Y-axis direction or the Z-axis direction, or both of the Y-axis direction and the Z-axis direction. In the present embodiment, the protrusion 151 is provided to protrude in both the Y-axis direction and the Z-axis direction, and when viewed along the X-axis direction, the substrate 15 is formed into a rectangular shape.

[0080] The surfaces on both sides of the protrusion 151 in the X-axis direction, that is, the two surfaces whose perpendicular lines are parallel to the X-axis, are not in contact with the housing 13 and the spacer 16 and are exposed, so the heat of the substrate 15 can be efficiently released to the outside from the protrusion 151. The heat dissipation from the protrusion 151 can reduce the temperature rise around the magnetic detection unit 12 provided on the substrate 15 due to the residual heat of the bus bar 11. Therefore, the degradation of the measurement accuracy of the current sensor 1 caused by the heat generated by the bus bar 11 can be suppressed.

[0081] The housing 13 includes a main body 17 on the X1 side in the X-axis direction of the spacer 16. The main body 17 includes an extension portion 18 extending from a portion where the spacer 16 is provided in a direction including the protruding direction. By providing the extension portion 18 on the main body 17, the protruding portion 151 can be protected by the extension portion 18, and when handling the current sensor 1, the risk of the protruding portion 151 colliding with an external obstacle and damaging the substrate 15 and components provided on the substrate 15 can be reduced.

[0082] <Modification>

[0083] Figure 3 It is a cross-sectional view of a current sensor 2 which is a modified example of the current sensor 1 .

[0084] As shown in the figure, the current sensor 2 is different from the current sensor 1 in that the extension portion 18 includes a facing portion 181 and a protection portion 182 .

[0085] The facing portion 181 is a portion disposed to face the protruding portion 151 , that is, a portion of the extending portion 18 that overlaps with the protruding portion 151 when viewed along the X-axis direction.

[0086] The protection portion 182 is a portion that is located outside the end portion 151E of the protrusion 151 when viewed along the X-axis direction and does not overlap with the protrusion 151 .

[0087] Since the extension portion 18 includes the protection portion 182 in addition to the facing portion 181, the extension portion 18 is likely to come into contact with the outside before the protrusion 151. Therefore, the risk of the protrusion 151 coming into contact with the outside and damaging the substrate 15 can be reduced.

[0088] The current sensor 2 is different from the current sensor 1 in that it includes a second magnetic shield 14B in addition to the first magnetic shield 14A. The components are arranged in order from the X1 side to the X2 side in the X-axis direction: the second magnetic shield 14B, the bus bar 11, the magnetic detection unit 12, the substrate 15, and the first magnetic shield 14A.

[0089] The second magnetic shield 14B disposed near the bus bar 11 is formed integrally with the main body 17 of the housing 13 together with the bus bar 11. The bus bar 11 and the magnetic detection unit 12 are disposed between the first magnetic shield 14A and the second magnetic shield 14B, so that noise caused by a disturbance magnetic field can be effectively suppressed, thereby achieving a current sensor 2 with high measurement accuracy.

[0090] [Second embodiment]

[0091] Figure 4 and Figure 5 It is a cross-sectional view and a top view of the current sensor 3 according to the present embodiment.

[0092] As shown in these figures, the current sensor 3 differs from the current sensors 1 and 2 in that the main body 37 of the housing 33 includes a guard portion 383 extending from the protection portion 382 of the extension portion 38 toward the X2 side in the X-axis direction.

[0093] like Figure 4 As shown, the distance L1 from the protection portion 382 to the end 383E of the protection portion 383 in the X-axis direction is greater than the distance L2 from the protection portion 382 to the installation surface 15S of the first magnetic shield 14A of the substrate 15 and less than the distance L3 from the protection portion 382 to the upper surface 14AS of the first magnetic shield 14A (L2≤L1≤L3). Therefore, the end 383E of the protection portion 383 is located between the upper surface 14AS of the first magnetic shield 14A and the installation surface 15S of the first magnetic shield 14A of the substrate 15.

[0094] In addition, if Figure 5As shown, when viewed along the X-axis direction, the guard 383 is separated from the protrusion 151, so the guard 383 is likely to contact the outside before the protrusion 151. Therefore, the guard 383 can protect the protrusion 151, reducing the risk of the protrusion 151 colliding with external obstacles and damaging the substrate 15, etc.

[0095] The current sensor 3 is also different from the current sensor 1 and the current sensor 2 in that the spacer 36 has a connecting portion 39 that is open in a direction intersecting the X-axis direction. In the current sensor 3, the spacer 36 is composed of four columnar bodies, and the gap between adjacent columnar bodies corresponds to the connecting portion 39Y that is open in the Y-axis direction and the connecting portion 39Z that is open in the Z-axis direction. In addition, the spacer 36 may also be composed of more than four columnar bodies, or a connecting portion 39 is provided only in either the Y-axis direction or the Z-axis direction. In addition, the spacer 36 may also be formed by a plate-like body having a hole that functions as the connecting portion 39. By providing the connecting portion 39, heat can be released to the outside through the connecting portion 39, and the peripheral temperature of the magnetic detection unit 12 can be prevented from becoming high.

[0096] <Modification>

[0097] Figure 6 As Figure 4 , Figure 5 FIG. 4 is a top view of a current sensor 4 which is a modified example of the current sensor 3 .

[0098] In the current sensor 4 shown in the figure, at least a part of the guard portion 483 overlaps with the protrusion 151 when viewed along at least one of the Y-axis direction and the Z-axis direction. That is, the guard portion 483 includes a guard portion 483Y that overlaps with the protrusion 151 when viewed along the Y-axis direction, and a guard portion 483Z that overlaps with the protrusion 151 when viewed along the Z-axis direction. According to this configuration, the guard portions 483 provided at the four corners of the protection portion 482 of the extension portion 48 can respectively surround the corners of the protrusion 151. Therefore, during operation, the risk of the protrusion 151 contacting the outside and damaging the substrate 15 and the like can be reduced.

[0099] exist Figure 6 In the embodiment, the guard portions 483 provided at the four corners are all provided with the guard portions 483Y and the guard portions 483Z, but a part of the guard portions 483 or all of the guard portions 483 may be provided with either the guard portions 483Y or the guard portions 483Z.

[0100] Figure 7 As Figure 4 FIG. 5 is a top view of a current sensor 5 according to another modified example of the current sensor 3 .

[0101] The guard 583 of the current sensor 5 shown in the figure is composed of a plurality of plate-like bodies 584, and gaps 585 are provided between adjacent plate-like bodies 584. With this configuration, the ratio of the plate-like bodies 584 and the gaps 585 constituting the guard 583 can be adjusted to achieve a balance between the protection of the protrusion 151 and the cooling effect of the substrate 15.

[0102] In addition, Figure 7 In the embodiment, a gap 585 is provided between the guard portion 583 and the plate-like body 584, but the gap 585 may be eliminated. Figure 6 Even without the gap 585, the substrate 15 and the spacer 36 are separated from the protection portion 583, so that the passage of air can be ensured and the heat can be fully released.

[0103] [Third Embodiment]

[0104] Figure 8 1 is a cross-sectional view of the current sensor 6 of the present embodiment. As shown in the figure, the current sensor 6 is different from the current sensor 6 in that the side surface 14AL of the first magnetic shield 14A held by the substrate 65 is covered by the substrate 65. Figure 2A The current sensor 1 is different.

[0105] The first magnetic shield 14A is formed by punching a plate material that has been subjected to surface treatment such as plating on both surfaces, using a press die or the like, to perform a punching process to perform a punching process on the plate surface (upper surface 14AS and lower surface) of the first magnetic shield 14A, but the side surface 14AL that becomes the fracture surface of the punching process is not subjected to a surface treatment. Therefore, if the side surface 14AL is exposed without performing a secondary process such as plating, rust may form on the side surface 14AL, and the rust may fall onto the wiring portion disposed around it, causing a short circuit or the like.

[0106] Therefore, the current sensor 6 of the present embodiment includes the covering portion 64 that covers the side surface 14AL of the first magnetic shield 14 . Figure 8 The side surface 14AL of the first magnetic shield 14A of the current sensor 6 shown is covered by the substrate 65, and the substrate 65 functions as the covering portion 64. Therefore, even when the side surface 14AL is a fractured surface, the generation of rust from the side surface 14AL of the first magnetic shield 14A can be reduced.

[0107] The current sensor 6 covers the side surface 14AL by burying the first magnetic shield 14A in the substrate 65. Therefore, there is no need to separately provide a cover for covering the side surface 14AL, so the size of the current sensor 6 can be reduced. In addition, since the upper surface 14AS of the first magnetic shield 14A exposed from the substrate 65 is generally subjected to surface treatment as described above, the side surface 14AL consisting of the fracture surface is covered with the substrate 65 (buried in the substrate 65), and the fracture surface can be prevented from being exposed.

[0108] <Modification>

[0109] Fig. 9 as well as Fig.10 As Figure 8 2 is a cross-sectional view of a current sensor 6a which is a modified example of the current sensor 6 and a cross-sectional view of a current sensor 6b which is another modified example.

[0110] Fig. 9 In the illustrated current sensor 6 a , the side surface 14AL of the first magnetic shield 14A is covered with an adhesive 66 that bonds the first magnetic shield 14A and the substrate 15 , and the adhesive 66 functions as a covering portion 64 .

[0111] Fig.10 In the current sensor 6b shown, the surface of the first magnetic shield 14A is plated with a layer 67 and is mounted on the substrate 15 using a solder 68, and the side surface 14AL of the first magnetic shield 14A is covered with the plated layer 67. In addition, since the first magnetic shield 14A is covered with the plated layer 67 as the cover 64, the side surface 14AL does not rust. Therefore, the first magnetic shield 14A may be bonded to the substrate 15 using an adhesive 66 or the like instead of the solder 68. In addition, when the solder 68 is used, the portion where the first magnetic shield 14A is welded and fixed to the substrate 15 may be any of the entire circumference of the first magnetic shield 14A, only the side wall, or a point (a plurality of points).

[0112] according to Figure 8 to Figure 10 In the configuration shown, a cover covering the side surface 14AL of the first magnetic shield 14A is not provided, but the side surface 14AL is covered by the cover portion 64, thereby preventing the fracture surface of the first magnetic shield 14A from being exposed to the outside. Therefore, rusting of the first magnetic shield 14A can be suppressed without increasing the size of the current sensors 6, 6a, 6b.

[0113] [Fourth Embodiment]

[0114] Fig.11 and Fig.12 It is a perspective view and a cross-sectional view of the current sensor 7 according to the present embodiment. Fig.12 express Fig.11 The cross section of line AA in .

[0115] The current sensor 7 is different from the current sensors 1 and 2 in that it includes three measurement phases 71 having bus bars 11 and magnetic detection units 12 . The three bus bars 11 are provided on a case 73 , and the three magnetic detection units 12 are provided on a substrate 75 .

[0116] In addition, Fig.11 and Fig.12 Although the current sensor 7 having three measurement phases 71 is exemplified in the embodiment, the present invention may be implemented as a current sensor having two or four or more measurement phases 71 .

[0117] Fig.13 2 is a cross-sectional view of a current sensor 8 as a modified example of the current sensor 7. The current sensor 8 is provided with a set of a first magnetic shield 84A and a second magnetic shield 84B for three measurement phases 71. In other words, the first magnetic shield 84A and the second magnetic shield 84B are arranged across the three measurement phases 71. In this way, the first magnetic shield 84A and the second magnetic shield 84B can also be shared by a plurality of measurement phases 71.

[0118] However, when there are a plurality of measurement phases 71 , if a configuration is adopted in which a set of first magnetic shield 84A and second magnetic shield 84B is provided for the plurality of measurement phases 71 as in the current sensor 8 , the first magnetic shield 84A and the second magnetic shield 84B are easily magnetically saturated.

[0119] In contrast, by independently providing the first magnetic shield 14A and the second magnetic shield 14B for each measurement phase 71 as in the current sensor 7, the first magnetic shield 14A and the second magnetic shield 14B are less likely to be magnetically saturated. Therefore, from the viewpoint of improving measurement accuracy, when a plurality of measurement phases 71 are provided, it is preferable to independently provide the first magnetic shield 14A and the second magnetic shield 14B for each measurement phase 71 as in the current sensor 7.

[0120] [Fifth Embodiment]

[0121] Fig.14: is a cross-sectional view of the current sensor 9 of the present embodiment. As shown in the figure, in the current sensor 9, the distance D1 between the first magnetic shield 94A and the bus bar 11 in the X-axis direction is greater than the distance D2 between the second magnetic shield 94B and the bus bar 11 in the first direction (D1>D2). In addition, the thickness T1 of the first magnetic shield 94A is smaller than the thickness T2 of the second magnetic shield 94B (T1<T2). In this way, by adjusting the thickness T1 of the first magnetic shield 94A and the thickness T2 of the second magnetic shield 94B according to the distances D1 and D2 from the bus bar 11, the size of the current sensor 9 in the X-axis direction can be reduced. In addition, the distances D1 and D2 refer to the distances between the centers of the components in the X-axis direction.

[0122] The performance of the magnetic shield varies depending on the distance from the bus bar 11, the shape of the magnetic shield, etc. Therefore, the thicknesses T1 and T2 can be adjusted to a range that provides an appropriate shielding function according to the distances D1 and D2 and the shapes of the first magnetic shield 94A and the second magnetic shield 94B. For example, it is preferable to set T1 to a value that is not less than 1 / 2 and not more than 2 / 3 of T2.

[0123] The embodiments disclosed in this specification are illustrative in all aspects and are not limited to the embodiments. The scope of the present invention is indicated not only by the description of the above embodiments but also by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0124] Example

[0125] In this embodiment, the relationship between the installation position of the first magnetic shield 14A and the error is measured. Fig.12 The current sensor 7 of the fourth embodiment shown in FIG. Fig.16 A conventional current sensor 100 is shown.

[0126] Fig.16 1 is a cross-sectional view of a conventional current sensor 100 having three measurement phases. The current sensor 100 is different from the conventional current sensor 100 in that the first magnetic shield 14A is integrally formed with the housing 103A. Fig.12 The current sensor 7 is different.

[0127] Regarding the experimental conditions, the distance between adjacent measurement phases 71 was set to 20 mm for the current sensor 7 and the current sensor 100 , and current was passed through the bus bar 11 under the same conditions to measure the error caused by the influence from the adjacent bus bar 11 .

[0128] The error of the current sensor 7 is 0.03%, whereas the error of the current sensor 100 is 0.1%. This result shows that by providing the first magnetic shield 14A on the substrate 15, the error caused by the influence of the adjacent bus bar 11 can be reduced compared to the case where the first magnetic shield 14A is formed integrally with the housing 103A.

[0129] Industrial Applicability

[0130] The present invention is useful as a current sensor including a bus bar through which a large current to be measured flows.

[0131] Description of Reference Numerals

[0132] 1, 2, 3, 4, 5, 6, 6a, 6b, 7, 8, 9: Current sensor

[0133] 11: Busbar

[0134] 12: Magnetic detection unit

[0135] 13: Shell

[0136] 14A: First magnetic shield

[0137] 14AL: Side

[0138] 14AS: Upper surface

[0139] 14B: Second magnetic shield

[0140] 15: Substrate

[0141] 15S: Setting the surface

[0142] 151: Protrusion

[0143] 151E: End

[0144] 16: Spacer

[0145] 17: Main body

[0146] 18: Extension

[0147] 181: Opposing part

[0148] 182: Protection Department

[0149] 33: Shell

[0150] 36: Interval

[0151] 37: Main body

[0152] 38: Extension setting part

[0153] 382: Protection Department

[0154] 383: Protection Department

[0155] 383E: End

[0156] 39: Connecting Department

[0157] 39Y: Connecting part

[0158] 39Z: Connecting Department

[0159] 48: Extension setting section

[0160] 482: Protection Department

[0161] 483: Protection Department

[0162] 483Y: Protection Department

[0163] 483Z: Protection Department

[0164] 583: Protection Department

[0165] 584: plate-like body

[0166] 585: Gap

[0167] 64: Covering

[0168] 65: Substrate

[0169] 66: Adhesive

[0170] 67: Plating

[0171] 68: Solder

[0172] 71: Determination of phase

[0173] 73: Shell

[0174] 75: Substrate

[0175] 84A: First magnetic shield

[0176] 84B: Second magnetic shield

[0177] 90: Current sensor

[0178] 93A: Shell

[0179] 93B: Shell

[0180] 94A: First magnetic shield

[0181] 94B: Second magnetic shield

[0182] 100: Current sensor

[0183] 103A: Shell

[0184] D1: Distance

[0185] D2: Distance

[0186] L1: Distance

[0187] L2: Distance

[0188] L3: Distance

[0189] T1: Thickness

[0190] T2: Thickness

Claims

1. A current sensor, comprising: Busbar, through which the measured current flows; a magnetic detection unit capable of detecting a magnetic field generated when the measured current flows through the bus bar; a housing for holding the bus bar; a first magnetic shield capable of suppressing disturbance magnetic field noise applied to the magnetic detection unit; as well as The substrate, when three mutually orthogonal directions are defined as a first direction, a second direction, and a third direction, is provided with the magnetic detection unit on a surface on one side in the first direction, In the current sensor, the bus bar, the magnetic detection unit, the substrate, and the first magnetic shield are arranged in order from one side in the first direction. The current sensor is characterized in that A spacer is provided between the housing and the substrate to separate the bus bar and the magnetic detection unit in the first direction. The substrate includes a protruding portion that protrudes from a position held by the spacer in a protruding direction consisting of at least one of the second direction and the third direction.

2. The current sensor according to claim 1, wherein: The partition is provided integrally with the housing.

3. The current sensor according to claim 1, wherein: The housing includes a main body on one side of the partition in the first direction. The main body includes an extending portion extending from a portion where the spacer is provided in a direction including the protruding direction.

4. The current sensor according to claim 3, wherein: The extending portion includes a facing portion overlapping the protruding portion and a protecting portion located outside an end portion of the protruding portion when viewed along the first direction.

5. The current sensor according to claim 4, wherein: The housing includes a guard portion extending from the protection portion toward the other side in the first direction. When viewed along the first direction, the guard portion is separated from the protrusion.

6. The current sensor according to claim 5, wherein: A distance from the protection portion to an end of the guard portion in the first direction is greater than or equal to a distance from the protection portion to a surface of the substrate on which the first magnetic shield is installed, and less than or equal to a distance from the protection portion to an upper surface of the first magnetic shield.

7. The current sensor according to claim 5, wherein: At least a portion of the guard portion overlaps with the protrusion when viewed along at least one of the second direction and the third direction.

8. The current sensor according to claim 7, wherein: The protection part is a plurality of plate-shaped bodies, and gaps are provided between adjacent plate-shaped bodies.

9. The current sensor according to claim 1, wherein: The first magnetic shield is held on the substrate, The side surface of the first magnetic shield is covered by a covering portion.

10. The current sensor according to claim 1, wherein: A plurality of measuring phases including the bus bar and the magnetic detection unit are provided, The first magnetic shield is independently provided for each of the measurement phases.

11. The current sensor according to claim 1, wherein: The partition portion includes a communication portion that is open in the second direction and / or the third direction.

12. The current sensor according to any one of claims 1 to 11, wherein: The spacer surrounds the magnetic detection section when viewed along the first direction.

13. The current sensor according to claim 1, wherein: further comprising a second magnetic shield, In the current sensor, the second magnetic shield, the bus bar, the magnetic detection unit, the substrate, and the first magnetic shield are arranged in this order from one side in the first direction.

14. The current sensor according to claim 13, wherein: The distance between the first magnetic shield and the bus bar in the first direction is greater than the distance between the second magnetic shield and the bus bar in the first direction, and the thickness of the first magnetic shield is less than the thickness of the second magnetic shield.

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