JP5849914B2 - Current sensor - Google Patents

Description

  The present invention relates to a current sensor including a magnetic detection element and a bias magnet that applies a bias magnetic field to the magnetic detection element.

  Conventionally, a current sensor including a magnetic detection element that outputs a sensor signal corresponding to an applied magnetic field and a bias magnet that applies a bias magnetic field to the magnetic detection element is known (see, for example, Patent Document 1). .

  Such a current sensor is used, for example, to measure a detected current flowing in a bus bar or the like as a detected current path. Specifically, the current sensor is assembled to the bus bar so that the current direction of the detected current is parallel to the bias magnetic field. When a current to be detected flows through the bus bar, a current magnetic field proportional to the current to be detected is formed in a direction perpendicular to the bias magnetic field. Therefore, the magnetic detection element has a combined magnetic field composed of the bias magnetic field and the current magnetic field. Applied. Therefore, a sensor signal corresponding to the combined magnetic field is output from the magnetic detection element.

JP 2007-155399 A

  Recently, a current sensor has been proposed in which a magnetic detection element is directly mounted at the center of a bias magnet made of a so-called bar magnet having a rectangular plate shape. According to this, since the magnetic detection element is mounted on the bias magnet, the size in the planar direction can be reduced.

  However, in such a current sensor, there is a problem that detection accuracy is lowered when the mounting position of the magnetic detection element on the bias magnet is deviated from the center of the bias magnet.

  That is, on one surface of the bias magnet on which the magnetic detection element is mounted, as shown in FIG. 5, the arrangement direction of the N pole and the S pole is the X direction (left and right direction in FIG. 5), and is orthogonal to the X direction. If the direction parallel to the surface direction is the Y direction (up and down direction in FIG. 5), the magnetic field passes through the center of the bias magnet, extends in the X direction, and expands in the Y direction with respect to the magnetic field lines. It is composed of magnetic field lines. In other words, the magnetic field lines extending in the X direction are formed only on the center of the bias magnet.

  The current sensor is arranged and used so that the current direction of the detected current flowing through the bus bar or the like as the detected current path is parallel to the X direction. For this reason, for example, when the magnetic detection element J20 is arranged in the region A that is shifted from the center of the bias magnet J30, the magnetic field lines passing through the magnetic detection element J20 and the current magnetic field do not become perpendicular, and the detection accuracy decreases. End up.

  In the space located on one surface of the bias magnet, magnetic field lines in the same direction as the magnetic field lines formed on one surface of the bias magnet are formed. Therefore, in the above description, the current sensor in which the magnetic detection element is directly mounted on the bias magnet is described as an example. For example, the bias magnet is mounted on one side of the substrate, and the other side of the substrate is A similar problem occurs in a current sensor in which a magnetic detection element is mounted so as to face the center of the bias magnet.

  In view of the above points, an object of the present invention is to provide a current sensor that can suppress a decrease in detection accuracy even when the mounting position of a magnetic detection element is shifted.

To achieve the above object, according to the first aspect of the present invention, the bias magnet is provided with a bottom portion (31) having one surface (31a) and one surface of the bottom portion, and N protruding in a direction perpendicular to the surface direction of the one surface. The first side portion (32) of the pole and the S pole provided in a region different from the first side portion of one surface of the bottom portion, projecting in a direction perpendicular to the surface direction of the one surface, and arranged to face the first side portion. A second side portion (33), and the bottom portion is divided in a direction perpendicular to the arrangement direction of the first and second side portions on the one surface side and along the one surface. The side region (31b) is an N pole, the second side region (31d) is an S pole, and the magnetic detection element is arranged in the arrangement direction of the first and second side portions. It arrange | positions in the state which passes along the magnetic force line extended in the direction parallel to.

  According to this, on one surface of the bottom portion, there are magnetic lines of force extending in the arrangement direction of the first and second side portions in a portion disposed between the central portion of the first side portion and the central portion of the second side portion. It is configured (see FIG. 6). That is, the lines of magnetic force extending in the arrangement direction of the first and second side portions can be increased with respect to the conventional bias magnet. For this reason, even if the mounting position of the magnetic detection element is slightly deviated from the center of the one surface of the bottom, magnetic lines of force in a direction parallel to the arrangement direction of the first and second side portions pass through the magnetic detection element. A decrease in detection accuracy can be suppressed. In other words, the attachment range of the magnetic detection element can be widened without reducing the detection accuracy.

  In this case, as in the second aspect of the present invention, the bias magnet includes two biasing magnets having a first side portion extending in a direction perpendicular to the surface direction of one surface and a first central region sandwiched between the first central region. The first end region (32b) is integrally formed, and the second side portion extends in a direction perpendicular to the surface direction of the one surface, and the second central region (33a) arranged to face the first central region. The second end region (33b), which is disposed opposite to the first end region with the second center region in between, is integrally formed, and is configured between the first and second center regions. The magnetic field may be weaker than the magnetic field configured between the first and second end regions facing each other.

  According to this, among the magnetic force lines formed between the first and second central regions, the magnetic force lines on the first and second end region sides are formed between the opposing first and second end regions. The magnetic field lines are likely to be parallel to the arrangement direction of the first and second side portions due to interference with the magnetic field lines on the first and second central region sides. For this reason, it is possible to further increase the lines of magnetic force that are parallel to the arrangement direction of the first and second side portions, and it is possible to further suppress a decrease in detection accuracy due to a shift in the mounting position of the magnetic detection element.

According to a sixth aspect of the present invention, the bias magnet has a bottom portion whose direction is perpendicular to the arrangement direction of the first and second side portions and whose polarity is divided along one surface. polarity is divided in the thickness direction, the first region (31b), a second region (31c which is connected to the first region in the thickness direction which is the N-pole is an area of the first side portion of the one side ), a third area that is an S pole is an area of the second side portion of the one side (31d), the fourth region being connected to the third region and the thickness direction (31e), a second It can be assumed that the region is an S pole and the fourth region is an N pole.

  According to this, since the bias magnet has a quadrupole structure, it is possible to improve control accuracy for creating a parallel magnetic field in a direction parallel to the arrangement direction of the first and second side portions while reducing the size. That is, when the bias magnet has a two-pole structure, the magnetic pole surface is formed in the first side portion or the second side portion by facing the direction parallel to the arrangement direction of the first and second side portions. Where the magnet length in the direction between the magnetized surfaces (X direction in FIG. 3) is short and the generated magnetic force is weak, the first side or the second side when the bias magnet has a four-pole structure. This makes it possible to increase the magnet length in the direction between the magnetized surfaces (the Z direction in FIG. 3). Therefore, when the bias magnet has a quadrupole structure, the strength of the magnetic field can be increased with a small volume, and by obtaining the necessary magnetic force with a small magnet, the arrangement direction of the first and second side portions can be determined. Control accuracy for creating a parallel magnetic field in parallel directions can be improved. In other words, the detection accuracy can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a schematic diagram when the current sensor in 1st Embodiment of this invention is assembled | attached to the bus-bar as a to-be-detected electric current path | route. It is arrow sectional drawing of the current sensor along the II-II line | wire in FIG. It is the top view which looked at the bias magnet from one side. It is sectional drawing along the IV-IV line in FIG. It is a figure which shows the magnetic field formed on one surface of the conventional bias magnet. It is a figure which shows the magnetic field formed on one surface of the bias magnet shown in FIG. It is the figure which looked at the bias magnet in 2nd Embodiment of this invention from the one surface side. It is a figure which shows interference of the magnetic force line of the dashed-two dotted line part in FIG. It is the figure which looked at the bias magnet in 3rd Embodiment of this invention from the one surface side. It is the figure which looked at the bias magnet in other embodiment of this invention from the one surface side. It is the figure which looked at the bias magnet in other embodiment of this invention from the one surface side. It is the figure which looked at the bias magnet in other embodiment of this invention from the one surface side. It is sectional drawing of the current sensor in other embodiment of this invention. It is sectional drawing which shows the relationship between the current sensor and bus bar in other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. Note that the current sensor in the present embodiment is preferably used for detecting a current to be detected flowing in a bus bar connected to an in-vehicle battery or the like.

  As shown in FIGS. 1 and 2, the current sensor includes a connection terminal 50 on which a magnetic detection element 20, a bias magnet 30, and a circuit chip 40 are mounted on a substrate 10 and electrically connected to the circuit chip 40. Each member 10-50 is sealed with the mold resin 60 so that the outer lead portion is exposed.

  The substrate 10 is composed of islands of lead frames having islands and connection leads formed by etching or pressing a plate material such as Cu or Fe, and a rectangular plate having one surface 10a and another surface 10b. It is made into a shape.

  The magnetic detection element 20 is configured using, for example, a well-known sensor chip on which an anisotropic magnetoresistive element (AMR), a giant magnetoresistive element (GMR), a tunnel porcelain resistive element (TMR), etc. are formed. A sensor signal corresponding to the applied magnetic field is output.

  The bias magnet 30 applies a bias magnetic field Bb to the magnetic detection element 20 and is composed of ferrite or the like. As shown in FIGS. 3 and 4, a rectangular plate-shaped bottom 31, The cross section is formed into a U-shape formed by first and second side portions 32 and 33 provided on one surface 31a.

  Specifically, the longitudinal direction in the surface direction of the bottom portion 31 is the X direction (left and right direction in FIG. 3), and the direction perpendicular to the X direction and parallel to the surface direction of the bottom portion 31 is the Y direction (up and down in FIG. 3). Direction), the direction orthogonal to the X direction and the Y direction is the Z direction (up and down direction in the drawing in FIG. 4), a columnar first side portion 32 protruding in the Z direction is provided at one end portion in the X direction of the bottom portion 31. A columnar second side portion 33 projecting in the Z direction is provided at the other end portion in the X direction of the bottom portion 31, and the first and second side portions 32 and 33 are arranged to face each other. In other words, the X direction can be said to be the direction in which the first and second side portions 32 and 33 are arranged. The first and second side portions 32 and 33 have the same length in the Y direction as the length of the bottom portion 31 in the Y direction.

  As shown in FIG. 4, the bias magnet 30 has a first side portion 32 as an N pole and a second side portion 33 as an S pole. Further, the bottom 31 is equally divided into two in the X direction and the Z direction (up and down direction in FIG. 4), and is on the one surface 31a side where the first and second side portions 33 and 33 are provided. The first region 31b connected to the first side portion 32 is the N pole, the second region 31c connected to the first region 31b in the thickness direction is the S pole, the one surface 31a side, and the second side portion. The third region 31d connected to 33 is an S pole, and the fourth region 31e connected to the third region 31d in the thickness direction is an N pole.

  That is, the bias magnet 30 of this embodiment is a quadrupole magnet. The magnetic detection element 20 is arranged at a substantially central portion of the one surface 31a of the bottom 31 of the bias magnet 30 so that a magnetic force line extending in the X direction passes through, as specifically described later.

  The bias magnetic field Bb applied to the magnetic detection element 20 is constituted by magnetic lines of force that pass through the magnetic detection element 20.

  As shown in FIGS. 1 and 2, the circuit chip 40 is arranged side by side with the bias magnet 30 on the one surface 10 a of the substrate 10. As this circuit chip 40, a well-known circuit chip in which a power circuit for applying a predetermined voltage to the magnetic detection element 20 and an arithmetic circuit for performing a predetermined arithmetic process on a sensor signal output from the magnetic detection element 20 is used. And is electrically connected to the magnetic detection element 20 via a wire (not shown).

  The connection terminal 50 is constituted by a connection lead of a lead frame, and is arranged separately from the substrate 10 outside the end portion of the substrate 10. And it is electrically connected to the circuit chip 40 via a wire (not shown).

  The mold resin 60 is made of, for example, an epoxy resin, and the substrate 10, the magnetic detection element 20, the bias magnet 30, and the circuit so that the outer lead portion (portion opposite to the substrate 10 side) of the connection terminal 50 is exposed. Of the chip 40 and the connection terminal 50, the inner lead portion (the portion on the substrate 10 side) is sealed.

  The above is the configuration of the current sensor in the present embodiment. Next, the magnetic field formed on one surface 31a of the bottom 31 of the bias magnet 30 will be described in comparison with the magnetic field formed on one surface of the bias magnet in the conventional current sensor.

  In the space located on the one surface 31a of the bottom 31 of the bias magnet 30, magnetic force lines in the same direction as the magnetic force lines formed on the one surface 31a of the bias magnet 30 are configured. That is, FIG. 5 is a diagram showing a magnetic field on one surface J31a of the bias magnet J30, and a diagram showing a magnetic field when the bias magnet J30 is viewed from the one surface J31a side. Similarly, FIG. 6 is a diagram showing a magnetic field on one surface 31 a of the bias magnet 30 and a magnetic field viewed from the one surface 31 a side of the bias magnet 30.

  First, as shown in FIG. 5, since the bias magnet J30 in the conventional current sensor has a rectangular plate shape, as described above, the surface J31a passes through the center of the bias magnet J30 in the X direction. The extending magnetic field lines and the magnetic field lines swollen in the Y direction with respect to the magnetic field lines are configured. That is, the magnetic field lines extending in the X direction are formed only on the center of the bias magnet J30.

  On the other hand, in the present embodiment, the bias magnet 30 is provided with a first side portion 32 that is an N pole and a second side portion 33 that is an S pole facing the bottom portion 31. For this reason, on one surface 31 a of the bottom portion 31, a magnetic force line extending in the X direction is formed at a portion disposed between the central portion of the first side portion 32 and the central portion of the second side portion 33.

  That is, the magnetic field lines in the X direction among the magnetic field lines formed on the one surface 31a of the bottom 31 can be increased with respect to the conventional bias magnet J30. For this reason, even if the mounting position of the magnetic detection element 20 is shifted from the center of the bottom 31 to the region A, the magnetic force lines extending in the X direction pass through the magnetic detection element 20.

  As shown in FIG. 1, the current sensor as described above is used by being assembled to a bus bar 70 corresponding to the detected current path of the present invention. Specifically, in the current sensor, the direction of the current flowing through the bus bar 70 (the left-right direction in FIG. 1) is parallel to the arrangement direction of the first and second side portions 32 and 33 (the X direction in FIG. 6). Thus, it is assembled to the bus bar 70. The magnetic detection element 20 outputs a sensor signal corresponding to the combined magnetic field Bs because the combined magnetic field Bs composed of the bias magnetic field Bb (lines of magnetic force passing through the magnetic detection element 20) and the current magnetic field Bi is applied. . Thus, the sensor signal is subjected to a predetermined calculation by the circuit chip 40 and then output to the external circuit via the connection terminal 50, and the detected current is measured by the external circuit.

  As described above, in the current sensor of this embodiment, the bias magnet 30 has a U-shaped cross section having the first and second side portions 32 and 33. For this reason, on one surface 31a of the bottom portion 31, a magnetic force line extending in the X direction is formed in a portion disposed between the central portion of the first side portion 32 and the central portion of the second side portion 33 (FIG. 6). reference). That is, the magnetic field lines in the X direction among the magnetic field lines formed on the one surface 31a of the bottom 31 can be increased with respect to the conventional bias magnet J30. For this reason, even if the mounting position of the magnetic detection element 20 is slightly deviated from the center of the one surface 31a of the bottom 31, the magnetic detection line 20 passes through the magnetic detection element 20 and suppresses a decrease in detection accuracy. it can. In other words, the attachment range of the magnetic detection element 20 can be widened without reducing the detection accuracy.

  In the present embodiment, since the bias magnet 30 has a quadrupole structure, it is possible to improve control accuracy for generating a parallel magnetic field in the X direction while reducing the size. That is, when the bias magnet 30 has a two-pole structure, the magnetic pole surface faces in the X direction, so that the direction between the magnetized surfaces formed by the first side portion 32 or the second side portion 33 (FIG. 3). When the bias magnet 30 has a quadrupole structure, the length of the magnet (in the X direction in the middle) is short and the generated magnetic force is weak, but the first side portion 32 or the second side portion 33 is configured. It becomes possible to lengthen the magnet length in the direction between the magnetized surfaces of the magnets (Z direction in FIG. 3). Therefore, when the bias magnet 30 has a quadrupole structure, the strength of the magnetic field can be increased with a small volume, and control for creating a parallel magnetic field in the X direction by obtaining a necessary magnetic force with a small magnet. Accuracy can be improved. In other words, the detection accuracy can be improved.

  In the bipolar magnet 30 having a bipolar structure, the polarity of the bottom 31 is divided into two in the X direction, the region connected to the first side 32 is the N pole, and the region connected to the second side 33 is the S pole. It is a magnet.

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the configuration of the bias magnet 30 is changed with respect to the first embodiment, and the other aspects are the same as those in the first embodiment, and thus the description thereof is omitted here.

  As shown in FIG. 7, the bias magnet 30 according to the present embodiment is configured so that the first side portion 32 has a central portion of a surface facing the second side portion 33, and an end portion on the opposite side to the one surface 31 a of the bottom portion 31. A groove 34 reaching the one surface 31a of the bottom 31 extends in the Z direction. Further, in the second side portion 33, a groove 35 extending from the end portion on the side opposite to the one surface 31a of the bottom portion 31 to the one surface 31a of the bottom portion 31 extends in the Z direction at the center portion of the surface facing the first side portion 32. Has been. The grooves 34 and 35 have the same shape, and the grooves 34 and 35 face each other.

  In other words, the first side portion 32 of the present embodiment is composed of three regions divided into three in the Y direction. The first central region 32a and the first central region 32a are sandwiched between the first side region 32 and the second side portion 33. It can be said that the two first end regions 32b protruding in an integrated manner are configured. The second side portion 33 is composed of three regions divided into three in the Y direction. The second central region 33a and the two central regions 33a sandwiching the second central region 33a and projecting toward the first side portion 32. It can be said that the second end region 33b is integrated.

  That is, in the bias magnet 30 of the present embodiment, the interval between the first and second central regions 32a and 33a facing each other is longer than the interval between the first and second end regions 32b and 33b facing each other. For this reason, the magnetic field comprised between the 1st, 2nd center area | regions 32a and 33a which oppose becomes weaker than the magnetic field comprised between the 1st, 2nd edge part area | regions 32b and 33b which oppose.

  According to this, as shown in FIG. 8, the magnetic field lines on the first and second end regions 32 b and 33 b side among the magnetic field lines configured between the first and second central regions 32 a and 33 a facing each other are as follows. The first and second central regions 32a and 33a among the magnetic lines of force formed between the opposing first and second end regions 32b and 33b become magnetic lines of force bulging toward the first and second end regions 32b and 33b. The magnetic field lines on the side are magnetic field lines that swell toward the first and second central regions 32a and 33a. Moreover, the magnetic field comprised between the 1st, 2nd center area | regions 32a and 33a which oppose is made weaker than the magnetic field comprised between the 1st, 2nd edge part area | regions 32b and 33b which oppose.

  For this reason, as shown in FIG. 7 and FIG. 8, the magnetic field lines on the first and second end regions 32 b and 33 b side among the magnetic field lines formed between the first and second central regions 32 a and 33 a facing each other are Of the magnetic force lines formed between the opposing first and second end regions 32b and 33b, the magnetic force lines on the first and second central regions 32a and 33a side are likely to interfere with each other and become parallel to the X direction.

  Therefore, it is possible to further increase the magnetic lines of force extending in the X direction, and it is possible to further suppress the detection accuracy from being lowered with respect to the displacement of the mounting position of the magnetic detection element 20.

(Third embodiment)
A third embodiment of the present invention will be described. In the present embodiment, the configuration of the bias magnet 30 is changed with respect to the second embodiment, and the other aspects are the same as those of the second embodiment, and thus the description thereof is omitted here.

  As shown in FIG. 9, in the bias magnet 30 of the present embodiment, the groove 34 is not formed in the first side portion 32, and the length in the X direction in the first central region 32a and the first end region 32b. Are the same. Moreover, the groove | channel 35 is not formed in the 2nd side part 33, but the length of the X direction in the 2nd center area | region 33a and the 2nd edge part area | region 33b is made the same.

  In the present embodiment, the first and second central regions 32a and 33a of the first and second side portions 32 and 33 are made of ferrite, which is a weak magnetic material. In addition, the first and second end regions 32b and 33b of the first and second side portions 32 and 33 are ferromagnetic materials having stronger magnetism than the material constituting the first and second central regions 32a and 33a. It is composed of neodymium or samarium cobalt.

  Even in such a current sensor, the magnetic field formed between the first and second central regions 32a and 33a facing each other is weaker than the magnetic field formed between the first and second end regions 32b and 33b facing each other. Therefore, the same effect as the second embodiment can be obtained.

  In the present embodiment, the entire bias magnet 30 is made of a weak magnetic material, and the surface of the first end region 32b facing the second end region 33b and the first end of the second end region 33b. The same effect can be obtained even if a sheet or the like made of a ferromagnetic material is attached to the surface facing the end region 32b.

(Other embodiments)
(1) In the first to third embodiments, the magnetic detection element 20 and the bias magnet 30 are sealed with the mold resin 60. However, the magnetic detection element 20 and the bias magnet 30 are sealed with the mold resin 60. It does not have to be stopped. In this case, for example, only the magnetic detection element 20 may be sealed with a mold resin or the like.

  Moreover, it is good also as a current sensor which combined said each embodiment. That is, the first and second central regions 32a, the second embodiment and the third embodiment are combined to form the groove 34 on the first side 32 and the groove 35 on the second side 33. 33a may be made of a weak magnetic material, and the first and second end regions 32b and 33b may be made of a ferromagnetic material.

  Further, in each of the above embodiments, the bias magnet 30 may be a two-pole magnet.

  (2) In the second and third embodiments, the magnetic field formed between the opposed first and second central regions 32a and 33a is configured between the opposed first and second end regions 32b and 33b. Although the current sensor using the bias magnet 30 that becomes weaker than the magnetic field to be applied has been described, the configuration of the bias magnet 30 is not limited to the second and third embodiments.

  For example, as shown in FIG. 10, a groove 34 extends in the Z direction at the center of the surface of the first side portion 32 opposite to the surface facing the second side portion 33, and the second side portion 33. Of these, a groove 34 may be extended in the Z direction at the center of the surface opposite to the surface facing the first side portion 32. The magnetic field formed between the first and second side portions 32 and 33 also depends on the lengths of the first and second side portions 32 and 33 in the X direction, and the first and second side portions 32 and 33 are. When the distance between the two is constant in the Y direction, the magnetic field becomes stronger as the length in the X direction becomes longer. Therefore, the current sensor using such a bias magnet 30 is also used in the second and third embodiments. The same effect can be obtained.

  As a modification of the second embodiment, as shown in FIG. 11, the distance between the center of the first side portion 32 and the center of the second side portion 33 is the longest on the one surface 31 a of the bottom portion 31. A bias magnet 30 may be used in which the distance between the end portion in the Y direction of the first side portion 32 and the end portion in the Y direction of the second side portion 33 is the shortest. That is, the surface of the first side portion 32 that faces the second side portion 33 and the surface of the second side portion 33 that faces the first side portion 32 may be tapered.

  Similarly, as a modification of FIG. 10, as shown in FIG. 12, the surface on the opposite side to the surface facing the second side portion 33 in the first side portion 32 and the first side in the second side portion 33. The surface opposite to the one surface facing the portion 32 may be tapered.

  In the above embodiments, the bottom 31 is bonded to the substrate 10. However, the following may be employed. That is, as shown in FIG. 13A, the magnetic detection element 20 is directly mounted on one surface 10 a of the substrate 10, and the bias magnet 30 is arranged so that the magnetic detection element 20 and the central portion of the bottom portion 31 face each other. Of these, the end of the first and second side portions 32, 33 opposite to the one surface 31 a may be bonded to the substrate 10. 13B, as a modification of FIG. 13A, the first and second sides of the bias magnet 30 with the magnetic detection element 20 mounted on the one surface 31a of the bottom 31. You may make it join the edge part on the opposite side to the one surface 31a in the parts 32 and 33 to the board | substrate 10. FIG.

  Further, as shown in FIG. 13C, the magnetic detection element 20 is directly mounted on one surface 10 a of the substrate 10, and the magnetic detection element 20 and the central portion of the bottom portion 31 are opposed to the other surface 10 b of the substrate 10. As described above, the end portions of the first and second side portions 32 and 33 on the opposite side of the one surface 31a of the bias magnet 30 may be joined.

  Also in such a current sensor, as described above, the magnetic force lines in the same direction as the magnetic force lines formed on the one surface 31a of the bias magnet 30 are formed in the space located on the one surface 31a of the bottom portion 31 of the bias magnet 30. Therefore, the same effects as those in the above embodiments can be obtained.

  Further, as shown in FIG. 14A, the bottom 31 of the bias magnet 30 on which the magnetic detection element 20 is mounted on the one surface 31 a of the bottom 31 may be directly joined to the bus bar 70. Further, as shown in FIG. 14B, the magnetic detection element 20 is directly mounted on the bus bar 70, and the first of the bias magnets 30 so that the magnetic detection element 20 and the central portion of the bottom portion 31 face each other. The end of the second side portions 32 and 33 opposite to the one surface 31a may be joined to the bus bar 70. As shown in FIG. 14C, as a modification of FIG. 14B, the first and second sides of the bias magnet 30 with the magnetic detection element 20 mounted on the one surface 31a of the bottom 31. You may make it join the edge part on the opposite side to the one surface 31a in the parts 32 and 33 to the bus-bar 70. FIG. Further, as shown in FIG. 14D, the magnetic detection element 20 is directly mounted on one surface of the bus bar 70, and the center of the magnetic detection element 20 and the central portion of the bottom 31 are opposed to the other surface of the bus bar 70. As described above, the end portions of the first and second side portions 32 and 33 on the opposite side of the one surface 31a of the bias magnet 30 may be joined.

  In the case of such a current sensor, a portion of the magnetic detection element 20, the bias magnet 30, and the bus bar 70 on which the magnetic detection element 20 and the bias magnet 30 are mounted may be sealed with a mold resin or the like. Good. Alternatively, only the magnetic detection element 20 may be sealed with a mold resin or the like.

DESCRIPTION OF SYMBOLS 10 Board | substrate 20 Magnetic detection element 30 Bias magnet 31 Bottom part 31a One surface 32 1st side part 33 2nd side part

Claims (7)

A bias magnet (30) that generates a bias magnetic field (Bb) that constitutes a combined magnetic field (Bs) together with a current magnetic field (Bi) generated by the flow of the detected current through the detected current path (70);
A magnetic detection element (20) for outputting a sensor signal corresponding to the combined magnetic field,
The bias magnet includes a bottom portion (31) having one surface (31a), a first side portion (32) of an N pole that is provided on one surface of the bottom portion and projects in a direction perpendicular to the surface direction of the one surface, and the bottom portion. A second side portion (33) of an S pole that is provided in a region different from the first side portion of the one surface, protrudes in a direction perpendicular to the surface direction of the one surface and is opposed to the first side portion; Have
The bottom portion is divided in a direction perpendicular to the arrangement direction of the first and second side portions and along the one surface side on the one surface side, and the region (31b) on the first side portion side. Is the N pole, and the region (31d) on the second side is the S pole,
The current sensor, wherein the magnetic detection element is arranged in a state in which a magnetic force line extending in a direction parallel to the arrangement direction of the first and second side portions passes.   The bias magnet has a first central region (32a) whose first side extends in a direction perpendicular to the surface direction of the one surface, and two first end regions (32b) sandwiching the first central region. A second central region (33a) configured to be integrated with each other, the second side portion extending in a direction perpendicular to the surface direction of the one surface, and disposed opposite to the first central region; and the second central region The two second end regions (33b) that are sandwiched between the first end region and the two second end regions (33b), respectively, are configured integrally, and the magnetic field formed between the first and second central regions is: The current sensor according to claim 1, wherein the current sensor is weaker than a magnetic field formed between the first and second end regions facing each other. The bias magnet, the opposing first, the interval between the second central region facing the first current sensor according to claim 2, characterized in that it is longer than the distance of the second end region.   4. The current sensor according to claim 2, wherein in the bias magnet, the first and second central regions are made of a weak magnetic material with respect to the first and second end regions. 5.   The bias magnet has a length in a direction parallel to the arrangement direction of the first and second central regions shorter than a length in a direction parallel to the arrangement direction of the first and second end regions. The current sensor according to any one of claims 2 to 4, wherein: In the bias magnet, the bottom portion is a direction perpendicular to the arrangement direction of the first and second side portions and the polarity is divided in the direction along the one surface, and the polarity is divided in the thickness direction , A first region (31b) that is an N pole that is a region on the first side portion on the one surface side, a second region (31c) that is connected to the first region in the thickness direction, and on the one surface side A third region (31d) that is an S pole that is a region on the second side portion side, and a fourth region (31e) that is connected to the third region in the thickness direction, and the second region is The current sensor according to claim 1, wherein the S pole and the fourth region are N poles. The current sensor according to claim 1, wherein the magnetic detection element is mounted at a central portion of the one surface.

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