JP4629644B2 - Current detector - Google Patents

Description

The present invention relates to a current detection device including a current detection sensor that detects a current flowing through a bus bar.

Conventionally, as this type of current detection sensor, for example, as shown in Patent Documents 1 and 2, by forming a bus bar in a U shape, conductor portions that are arranged to face each other and in which currents flow in opposite directions are formed. A configuration in which a magnetic detection element is provided at an intermediate position of a conductor portion has been proposed. In such a current detection sensor, since the magnetic field generated by the current flowing in the conductor portion arranged oppositely (current flowing in the bus bar) is amplified at the intermediate position of the conductor portion, it does not have a core for concentrating the magnetic flux. A magnetic field can be detected. Therefore, the configuration of the current detection sensor can be simplified.
Japanese Patent Laid-Open No. 5-223849 JP-A-8-194016

  However, in such a current detection sensor, for example, when another bus bar is laid in the vicinity of a bus bar that is a current detection target, a magnetic field (disturbance magnetic field) generated by a current flowing in the bus bar in the vicinity is applied to the magnetic detection element. The disturbance magnetic field may be detected. That is, the conventional current detection sensor may not be able to obtain high detection accuracy due to the influence of the disturbance magnetic field.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a current detection device capable of obtaining high detection accuracy with a simple structure.

In order to solve the above-mentioned problem, in the invention according to claim 1, the elongated bus bar and a part of the bus bar are formed to be opposed to each other by being bent along a folding line intersecting the longitudinal direction. is interposed between a pair of object part, the current and a current detection sensor for detecting a current flowing to said examined portion by detecting a magnetic field generated between該被detection portion during energization of the longitudinal direction of the bus bar In the detection device , the current detection sensor includes a magnetic detection element disposed between the test parts, an insulating mold part that fits between the test parts while molding the magnetic detection element, and the insulation The gist of the present invention is that a shield portion made of a magnetic material integrally formed so as to be in non-contact with the bus bar is provided on both side surfaces which are both side portions of the bus bar in the mold portion.

  According to the above configuration, when a current flows through the bus bar, a magnetic field is generated between the test parts. And since a magnetic detection element is arrange | positioned between these test parts, the electric current which flows into a test part is reliably detected by this magnetic detection element. Moreover, since the magnetic sensing element is molded by the insulating mold part and the shield parts made of a magnetic material are integrally formed on both side surfaces of the insulating mold part, for example, a disturbance magnetic field generated by an adjacent bus bar or the like is generated. It is blocked by the shield part. Therefore, it is also suppressed that the disturbance magnetic field is detected by the magnetic detection element.

In the invention according to claim 2, in the current detection device according to claim 1, the formation part of the shield part in the insulating mold part is provided with a flange part that covers a part of both side parts of the bus bar, The gist of the invention is that the shield part extends to the flange part.

According to the above configuration, since the magnetic field generated in the test part can be concentrated on the shield part, the leakage magnetic flux can be suppressed.
The gist of the invention described in claim 3 is that, in the current detection device according to claim 1 or 2, a locking claw that locks the bus bar is provided in the insulating mold portion.

According to the above configuration, the current detection sensor can be reliably mounted (positioned) on the bus bar.
According to a fourth aspect of the present invention, in the current detection device according to any one of the first to third aspects, a protrusion projecting in the direction of the magnetic detection element is provided at a location corresponding to the magnetic detection element in the shield portion. A gist is that a recess that matches the protrusion is provided at a portion corresponding to the shield portion in the insulating mold portion.

  According to the above configuration, the bondability between the shield part and the insulating mold part is improved, and a suitable magnetic flux concentration with respect to the magnetic sensing element can be achieved, and the current detection accuracy is further improved.

As described above in detail, according to the present invention, it is possible to provide a current detection device capable of obtaining high detection accuracy with a simple structure.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying the present invention will be described in detail with reference to FIGS.
As shown in FIG. 1, a bent portion 2 having a substantially “U” cross section is formed on a part of a bus bar 1 made of an elongated plate-like object by being bent along a folding line orthogonal to the longitudinal direction. Is formed. For this reason, the bending part 2 has a pair of test parts 3 (first test part 3a and second test part 3b) facing each other and a connection part 4 for connecting the test parts 3a and 3b. And an installation recess 5 surrounded by the test portions 3a and 3b and the connection portion 4 are provided. As shown in FIG. 2, the current detection sensor 10 can be inserted into the installation recess 5.

  As shown in FIG. 3, the current detection sensor 10 includes a GMR element 12 as a magnetic detection element mounted on a lead frame 11, a pair of bias magnets 13 disposed on both sides of the GMR element 12, and these GMR elements. 12 and an insulating mold portion 14 made of a resin material for molding the bias magnet 13.

  Specifically, the lead frame 11 and the GMR element 12 are arranged at substantially the central location in the insulating mold portion 14, and the bias magnets 13 are arranged in the vicinity of both sides thereof. The lead frame 11 is formed with a plurality of (here, three) terminals 11a, and the insulating mold portion 14 is molded so that the terminals 11a protrude outward.

  The insulating mold portion 14 includes a substantially rectangular parallelepiped main body 14a that matches the installation recess 5 of the bus bar 1, and flange portions 14b that protrude in a direction orthogonal to the longitudinal direction at both end edges in the longitudinal direction of the main body 14a. ing. For this reason, the insulating mold part 14 has a substantially “H” shape in a front view. As shown in FIG. 2, the flange portion 14 b is set so as to cover both side surfaces of each of the test portions 3 a and 3 b when the current detection sensor 10 is inserted into the installation recess 5.

  In addition, as shown in FIGS. 1 to 3, both side edges of the surface of the insulating mold portion 14 that coincides with the connection portion 4 of the bus bar 1 are connected to the connection portion 4 when inserted into the installation recess 5. The engaging claw 15 to be engaged is projected. For this reason, the current detection sensor 10 is fixed to the installation recess 5 by the engagement of the locking claw 15 with the connection portion 4.

  Further, as shown in FIG. 3, recesses 16 are respectively provided at locations corresponding to the respective bias magnets 13 on both side surfaces of the insulating mold portion 14. And the shield part 17 which consists of a magnetic body in agreement with the outer peripheral surface of this flange part 14b is integrally formed in the both sides | surfaces of this insulating mold part 14, ie, the outer surface of the flange part 14b. Therefore, when the current detection sensor 10 is mounted in the installation recess 5, both side surfaces of the insulating mold portion 14 and both side surfaces of the test portions 3 a and 3 b in the bus bar 1 are caused by the shield portion 17. It will be covered. Further, the shield portion 17 is provided with a protrusion 17a that matches the recess 16, thereby enhancing the bondability with the flange portion 14b. Moreover, since the shield part 17 is provided via the flange part 14b, the shield part 17 and the bus bar 1 are not in contact with each other when the current detection sensor 10 is mounted in the installation recess 5 of the bus bar 1. It becomes.

Next, a manufacturing procedure of such a current detection sensor 10 will be described.
First, the GMR element 12 is mounted on the lead frame 11, and the lead frame 11, the bias magnets 13, and the shield part 17 are positioned at the corresponding locations, respectively, and the lead frame 11 and the bias magnet 13 are insulated by the insulating mold part 14. Is molded. As a result, the GMR element 12 and the bias magnet 13 mounted on the lead frame 11 are packaged, and the insulating mold portion 14 and the shield portion 17 are integrally formed. In addition, after the lead frame 11 and the bias magnet 13 are molded by the insulating mold part 14, the shield part 17 may be joined to the insulating mold part 14 by a resin adhesive or the like.

  When the current detection sensor 10 configured as described above is mounted in the installation recess 5 of the bus bar 1, the current detection sensor 10 is interposed between the test portions 3 a and 3 b of the bus bar 1. For this reason, when a current flows through the bus bar 1, a stronger magnetic field is generated in the installation recess 5 than at other locations of the bus bar 1. Since the GMR element 12 is placed in such a strong magnetic field, the generated magnetic flux can be detected efficiently. Therefore, the amount of current flowing through the bus bar 1 can be detected based on the magnetic signal thus detected.

  Further, shield portions 17 made of a magnetic material are disposed on both side surfaces of the insulating mold portion 14, and projections 17a projecting toward the GMR element 12 are provided at locations corresponding to the bias magnet 13 in the shield portion 17. Therefore, the magnetic flux collecting effect on the GMR element 12 is also enhanced. Therefore, the magnetic flux generated by the current flowing through the bus bar 1 can be detected more efficiently by the GMR element 12.

  By the way, the bus bar 1 is often laid adjacently. For example, as shown in FIG. 4, there are cases where other bus bars 21 and 22 are laid adjacently in the vicinity of the bus bar 1 as a current detection target. . In such a case, a magnetic field (disturbance magnetic field) generated when a current flows through the other bus bars 21 and 22 may affect the current detection sensor 10, and the current detection accuracy of the current detection sensor 10 may be reduced. is there. However, in the present embodiment, in the current detection sensor 10, since both sides of the insulating mold part 14 are covered with the shield part 17, such a disturbance magnetic field is blocked by the shield part 17.

  Specifically, as shown in FIG. 5, the degree of influence of the current I1 applied to the adjacent bus bars 21 and 22 on the magnetic flux B detected by the GMR element 12 is slightly less than 0.2%. It has been confirmed that. For this reason, the value of the magnetic flux B detected according to the current I2 flowing through the bus bar 1 to be detected, regardless of whether the value of the current I1 flowing through the adjacent bus bars 21 and 22 is “0A” or “350A”. Produces little change.

  On the other hand, when the shield part 17 is not provided in the current detection sensor 10, the degree of influence exerted by the current I <b> 1 supplied to the adjacent bus bars 21 and 22 on the magnetic flux B detected by the GMR element 12 is It has been confirmed that it is about 3%. For this reason, the value of the magnetic flux B detected by the GMR element 12 changes depending on whether the current flows in the adjacent bus bars 21 and 22 or not, and the current detection accuracy of the current detection sensor 10 is changed. Will fall.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) When a current flows through the bus bar 1 that is a current detection target, a strong magnetic field is generated in the installation recess 5 surrounded by the test portions 3a and 3b and the connection portion 4 as compared with other portions. By mounting the current detection sensor 10 in the installation recess 5, the GMR element 12 is placed in the installation recess 5, so that the magnetic flux generated by the current flowing through the bus bar 1 is surely generated by the GMR element 12. Detectable.

  In addition, the GMR element 12 is molded by the insulating mold portion 14, and shield portions 17 made of a magnetic material are integrally formed on both side surfaces of the insulating mold portion 14. For this reason, for example, a disturbance magnetic field generated by an adjacent bus bar or the like can be blocked by the shield portion 17, and the disturbance magnetic field can be suppressed from being detected by the GMR element 12. Therefore, the current detection accuracy of the current detection sensor 10 can be improved. Moreover, since the structure which only forms the shield part 17 integrally in the both sides of the insulation mold part 14 is sufficient, the electric current detection sensor 10 can be comprised simply.

  (2) A flange portion 14b that covers a part of both side portions of the bus bar 1 (both side surfaces of each of the test portions 3a and 3b) is provided at a portion where the shield portion 17 is formed in the insulating mold portion 14, and the shield portion 17 The flange portion 14b is extended. For this reason, the magnetic field which generate | occur | produces between each to-be-tested part 3a, 3b can be concentrated on the shield part 17, and a leakage magnetic flux can be suppressed.

  (3) The insulating mold portion 14 is provided with a pair of locking claws 15. When the current detection sensor 10 is mounted in the installation recess 5, the locking claws 15 engage with the connection portion 4 of the bus bar 1. To do. For this reason, the current sensor 10 can be reliably mounted (positioned) on the bus bar 1.

  (4) A protrusion 17a that protrudes toward the GMR element 12 is provided at a location corresponding to the GMR element 12 and the bias magnet 13 in the shield part 17, and the insulating mold part 14 has a recess that matches the protrusion 17a. A station 16 is provided. For this reason, the bondability between the shield part 17 and the insulating mold part 14 is improved, and a suitable magnetic flux concentration with respect to the GMR element 12 can be achieved, and the current detection accuracy can be further improved.

  (5) The shield part 17 is joined to the insulating mold part 14 in the step of molding the GMR element 12 and the bias magnet 13 by the insulating mold part 14. For this reason, since it is not necessary to make the process for joining the shield part 17 to the insulation mold part 14 into another process, the fall of productivity by increasing a manufacturing process can be suppressed.

In addition, you may change embodiment of this invention as follows.
In the embodiment, the current detection sensor 10 includes the GMR element 12 as a magnetic detection element and the bias magnet 13. However, the magnetic sensing element is not limited to the GMR element 12 and may be configured by another magnetic sensing element such as a Hall element. When a Hall element is used as the magnetic detection element, the bias magnet 13 may be omitted from the configuration of the current detection sensor 10.

  In the above embodiment, the current detection sensor 10 is manufactured by molding the already magnetized bias magnet 13 together with the GMR element 12 by the insulating mold part 14. However, the resin (plastic magnet) mixed with magnetic powder and the insulating mold portion 14 may be molded in two colors, and the plastic magnet may be magnetized by a partial magnetizing technique at the time of molding. .

  The insulating mold part 14 does not necessarily need to have the flange part 14b, and the shield part 17 does not necessarily have to be configured to cover both side surfaces of the test parts 3a and 3b.

-The latching claw 15 may be comprised by 2 or more pairs. Further, the locking claw 15 may be omitted.
The bent portion 2 does not necessarily have a substantially “U” shape in cross section, and may have another shape such as a substantially “U” shape in cross section. Further, the bent portion 2 does not necessarily have to be bent at a folding line orthogonal to the longitudinal direction of the bus bar 1.

-You may abbreviate | omit the recessed part 16 provided in the insulating mold part 14, and the protrusion 17a provided in the shield part 17. FIG.
Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.

(1) In the current detection sensor, the shield portion may be joined together to the magnetic sensing element in the insulating mold portion in the step of molding by the insulating molding unit.

(2) In the current detection sensor, the disposed bias magnet between the magnetic sensing element and the shield portion, the magnetic sensing element and said bias magnet is molded by the insulating mold part.

The perspective view which shows the electric current detection sensor of one Embodiment of this invention, and the bus bar by which the electric current detection sensor is arrange | positioned. The perspective view which shows the state which installed the electric current detection sensor of the embodiment in the bus-bar. AA sectional view taken on the line AA of FIG. The perspective view which shows roughly the installation aspect of the bus-bar of the embodiment. The graph which shows the magnetic flux detection example of the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Bus bar, 3 ... Test part (3a ... 1st test part, 3b ... 2nd test part), 5 ... Installation recessed part, 10 ... Current detection sensor, 12 ... GMR element as a magnetic detection element, 13 ... Bias magnet, 14 ... insulating mold part, 14b ... flange part, 15 ... locking claw, 16 ... recess, 17 ... shield part, 17a ... protrusion.

Claims (4)

An elongated bus bar and a portion of the bus bar that is bent at a folding line that intersects the longitudinal direction, and is interposed between a pair of test parts that are formed to face each other. A current detection device comprising a current detection sensor for detecting a current flowing in the test part by detecting a magnetic field generated at times between the test parts,
The current detection sensor includes: a magnetic detection element disposed between the test parts; an insulating mold part that fits between the test parts while molding the magnetic detection element; and the bus bar of the insulation mold part. A current detection device comprising: shield portions made of a magnetic material integrally formed on both side surfaces which are both side portions so as to be in non-contact with the bus bar. A flange portion that covers a part of both side portions of the bus bar is provided at a portion where the shield portion is formed in the insulating mold portion, and the shield portion extends to the flange portion. Item 2. The current detection device according to Item 1. The current detection device according to claim 1, wherein a locking claw that locks the bus bar is provided in the insulating mold part. Projections projecting in the direction of the magnetic sensing element are provided at locations corresponding to the magnetic sensing elements in the shield portion, and recesses that match the projecting portions are disposed at locations corresponding to the shield portions in the insulating mold portion. The current detection device according to claim 1, wherein the current detection device is provided .

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