WO2014045559A1

WO2014045559A1 - Current sensor

Info

Publication number: WO2014045559A1
Application number: PCT/JP2013/005449
Authority: WO
Inventors: 紀博車戸; 亮輔酒井
Original assignee: 株式会社デンソー
Priority date: 2012-09-19
Filing date: 2013-09-13
Publication date: 2014-03-27
Also published as: JP5849914B2; JP2014062738A

Abstract

This current sensor is provided with: a bias magnet (30) which generates a bias magnetic field (Bb) that constitutes a synthetic magnetic field (Bs) with a current magnetic field (Bi) generated when a current to be detected flows in a path (70) for the current to be detected; and a magnetic detection element (20) that outputs sensor signals corresponding to the synthetic magnetic field. The bias magnet has: a bottom portion (31) having one surface (31a); an N-pole first side portion (32), which is provided on the one surface of the bottom portion, and which protrudes in the direction perpendicular to the surface direction of the one surface; and an S-pole second side portion (33), which is provided in a region of the one surface of the bottom portion, said region being different from a region where the first side portion is provided, and which protrudes in the direction perpendicular to the surface direction of the one surface, and which is disposed to face the first side portion. The magnetic detection element is disposed in a state wherein magnetic lines extending in the direction parallel to the alignment direction of the first and second side portions pass through the magnetic detection element. Consequently, deterioration of detection accuracy can be suppressed even if the attaching position of the magnetic detection element is shifted.

Description

Current sensor

Cross-reference of related applications

This disclosure is based on Japanese Patent Application No. 2012-206288 filed on September 19, 2012, the contents of which are incorporated herein.

The present disclosure 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, for measuring 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, if the mounting position of the magnetic detection element on the bias magnet deviates from the center of the bias magnet, the detection accuracy is lowered.

That is, on one surface on which the magnetic detection element of the bias magnet is mounted, the arrangement direction of the N pole and the S pole is the first direction, the direction orthogonal to the first direction and parallel to the surface direction of the one surface is the second direction. Then, the magnetic field is constituted by magnetic lines extending in the first direction through the center of the bias magnet and magnetic lines expanded in the second direction with respect to the magnetic lines. In other words, the magnetic field lines extending in the first 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 first direction. For this reason, if a magnetic detection element is arrange | positioned in the area | region which shifted | deviated from the center of the bias magnet, for example, the magnetic field line which passes a magnetic detection element and an electric current magnetic field will not become perpendicular | vertical, but detection accuracy will fall.

In addition, the magnetic field lines in the same direction as the magnetic field lines formed on one surface of the bias magnet are formed in the space located on one surface of the bias magnet. 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 Similarly, in a current sensor in which a magnetic detection element is mounted so as to face the center of the bias magnet, the magnetic detection element passes through the magnetic detection element when it is disposed, for example, in a region shifted from the center of the bias magnet. The magnetic field lines and the current magnetic field are not perpendicular to each other, and the detection accuracy is lowered.

In view of the above points, it is an object of the present disclosure 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.

According to the first aspect of the present disclosure, in the current sensor, the bias magnet includes a bottom portion having one surface, and a first side portion of the 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. A second side portion of the S pole that is provided in a region different from the first side portion of the one surface of the bottom portion, protrudes in a direction perpendicular to the surface direction of the one surface and is disposed to face the first side portion, The magnetic detection element is characterized in that magnetic lines of force extending in a direction parallel to the arrangement direction of the first and second side portions are arranged in a state of passing through the magnetic detection element.

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. Composed. That is, the lines of magnetic force extending in the arrangement direction of the first and second side portions can be increased compared to a rectangular plate-shaped bias magnet having no first and second side portions. 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.

According to the second aspect of the present disclosure, in the current sensor according to the first aspect, the first side portion of the bias magnet extends in a direction perpendicular to the surface direction of the one surface, and the first central region sandwiches the first central region. The first center region and the first end region are integrally formed. The second side portion extends in a direction perpendicular to the surface direction of the one surface, and is disposed opposite to the first end region, with the second central region disposed opposite to the first central region, and the second central region interposed therebetween. Two second end regions, and the second central region and the second end region are integrally formed. In this bias magnet, the magnetic field formed between the first and second central regions may be weaker than the magnetic field formed between the opposing first and second end regions.

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 suppress a decrease in detection accuracy due to a shift in the mounting position of the magnetic detection element.

According to the third aspect of the present disclosure, in the current sensor according to the first aspect, the first to fourth regions in which the bottom portion of the bias magnet is divided in the plane direction of the bottom portion and in the thickness direction of the bottom portion. Have The first region connected to the first side is the N pole, the second region connected to the first region in the thickness direction is the S pole, and the third region connected to the second side is the S pole. The fourth region connected to the third region in the thickness direction may be an N pole.

According to this, since the bias magnet has a quadrupole structure, it is possible to improve control accuracy for generating 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 is short and the generated magnetic force is weak, when the bias magnet has a quadrupole structure, the magnet composed of the first side portion or the second side portion It is possible to increase the magnet length in the direction between the magnetized surfaces. 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.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawing
It is a mimetic diagram when attaching the current sensor in a 1st embodiment of this indication to the bus bar as a detected current course. FIG. 2 is a cross-sectional view of the current sensor along the line II-II in FIG. It is the top view which looked at the bias magnet from one side. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a figure which shows the magnetic field formed on one surface of the rectangular-plate-shaped bias magnet as a comparative example. 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 indication 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 indication from the one surface side. It is the figure which looked at the bias magnet in other embodiment of this indication from the one surface side. It is the figure which looked at the bias magnet in other embodiment of this indication from the one surface side. It is the figure which looked at the bias magnet in other embodiment of this indication from the one surface side. It is sectional drawing of the current sensor in other embodiment of this indication. It is sectional drawing of the current sensor in other embodiment of this indication. It is sectional drawing of the current sensor in other embodiment of this indication. It is sectional drawing which shows the relationship between the current sensor and bus bar in other embodiment of this indication. It is sectional drawing which shows the relationship between the current sensor and bus bar in other embodiment of this indication. It is sectional drawing which shows the relationship between the current sensor and bus bar in other embodiment of this indication. It is sectional drawing which shows the relationship between the current sensor and bus bar in other embodiment of this indication.

Hereinafter, embodiments of the present disclosure 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 disclosure 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 to 50 is sealed with a 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.

Here, the longitudinal direction in the surface direction of the bottom 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 31 is the Y direction (up and down direction in FIG. 3). A direction perpendicular to the X direction and the Y direction is defined as a Z direction (up and down direction 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, and a columnar second side portion protruding in the Z direction is provided at the other end portion in the X direction of the bottom portion 31. 33 is provided, 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 an arrangement direction of the first and

second side portions

32 and 33. 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 the first side portion 32 as an N pole and the 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.

Note that 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.

The circuit chip 40 is arranged side by side with the bias magnet 30 on one surface 10a of the substrate 10, as shown in FIGS. 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 composed of a connection lead of a lead frame, and is arranged separately from the substrate 10 outside the end 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 current sensor as a comparative example shown in FIG.

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 current sensor as a comparative example has a rectangular plate shape, as described above, the surface J31a passes through the center of the bias magnet J30, and X A magnetic field line extending in the direction (see arrow J1) and a magnetic field line bulging in the Y direction with respect to the magnetic field line (see arrow J2) 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 31a of the bottom portion 31, a magnetic force line (see arrow E1) 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. Is done.

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 bias magnet J30 of the comparative example. 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 described above, 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 disclosure. 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 bias magnet J30 of the comparative example. 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.

When the bias magnet 30 has a quadrupole structure, it is possible to improve control accuracy for creating 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 disclosure 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 out of the surfaces facing the second side portion 33, from the 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 this 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, among the magnetic lines of force formed between the first and second

central regions

32a and 33a facing each other, the magnetic lines of force on the first and

second end regions

32b and 33b side ( (Refer to E2 in FIG. 7) is the X direction by being interfered with the magnetic lines of force between the first and

second end regions

32b and 33b facing each other on the first and second

central regions

32a and 33a side. It is easy to become parallel with.

Therefore, it is possible to further increase the lines of magnetic force extending in the X direction, 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 20.

(Third embodiment)
A third embodiment of the present disclosure 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.

And in this embodiment, the 1st, 2nd center area |

regions

32a and 33a of the 1st,

2nd side parts

32 and 33 are comprised with the ferrite etc. which are weak magnetic materials. 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.

Also, a current sensor that combines the above embodiments may be used. 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.

Furthermore, 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 of the first side portion 32 opposite to the one surface facing the second side portion 33 and the first side of 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 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 substrate 10. 13B, as a modification of FIG. 13A, one surface of the first and

second side portions

32 and 33 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 31a to the board | substrate 10. FIG.

Further, as shown in FIG. 13C, the magnetic detection element 20 is directly mounted on one surface 10a of the substrate 10, and the magnetic detection element 20 and the central portion of the bottom 31 are opposed to the other surface 10b of the substrate 10. The ends 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 may be directly joined to the bus bar 70 on one surface 31a of the bottom 31. Further, as shown in FIG. 14B, the magnetic detection element 20 is directly mounted on the bus bar 70, and the first and second of the bias magnet 30 are arranged so that the magnetic detection element 20 and the central portion of the bottom 31 face each other. You may make it join the edge part on the opposite side to the one surface 31a in the

side parts

32 and 33 to the bus-bar 70. FIG. 14C, as a modification of FIG. 14B, one surface of the first and

second side portions

32 and 33 of the bias magnet 30 with the magnetic detection element 20 mounted on the one surface 31a of the bottom portion 31. You may make it join the edge part on the opposite side to 31a 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. The ends of the first and

second side portions

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.

Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

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 magnetic sensor is arranged in such a manner that magnetic lines extending in a direction parallel to the arrangement direction of the first and second side portions pass through the magnetic sensor.
The first side portion of the bias magnet has a first central region (32a) extending in a direction perpendicular to the surface direction of the one surface, and two first end regions (32b) sandwiching the first central region. The first central region and the first end region are integrally formed;
The second side portion of the bias magnetic field extends in a direction perpendicular to the surface direction of the one surface and sandwiches the second central region with a second central region (33a) disposed opposite to the first central region, The first end region and the two second end regions (33b) disposed opposite to each other, the second central region and the second end region are configured integrally;
In the bias magnetic field, a magnetic field formed between the first and second central regions is weaker than a magnetic field formed between the opposed first and second end regions. The current sensor according to claim 1.
3. The current sensor according to claim 2, wherein the bias magnet has an interval between the first and second central regions longer than an interval between the first and second end regions.
4. The current sensor according to claim 2, wherein the first and second central regions of the bias magnet are made of a weak magnetic material with respect to the first and second end regions.
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:
The bottom portion of the bias magnet has first to fourth regions (31b to 31e) which are divided in the planar direction and divided in the thickness direction, and are connected to the first side portion. Is the N pole, the second region connected to the first region in the thickness direction is the S pole, the third region connected to the second side is the S pole, and the third region is in the thickness direction. The current sensor according to any one of claims 1 to 5, wherein the connected fourth region has an N pole.
The current sensor according to any one of claims 1 to 6, wherein the magnetic detection element is mounted at a central portion of the one surface.