JP2013101014A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current detector capable of positioning an electromagnetic transducer in a gap part of a magnetic body core while suppressing variance on current detection sensitivity and easily mounting electronic components including the electromagnetic transducer on an electronic board.SOLUTION: An insulation casing 40 of a current detector 1 supports and houses an electronic board 50 on which a magnetic body core 10 and a Hall element 20 are mounted. The insulation casing 40 includes a first screw seat 461 and a second screw seat 462 in which a first screw 61 and a second screw 62 for fixing the electronic board 50 to the insulation casing 40 are screwed. The first screw seat 461, which is a part where a screw hole for screwing the first screw 461 is formed, is disposed at a position passed through a gap 12 of the magnetic body core 10 supported by the insulation housing 40 and along a plane orthogonal to a direction where both ends 13 of the magnetic body core 10 face each other. The first screw 61 penetrates the electronic board 50 without any play, and the second screw 62 penetrates the electronic board 50 with play.

Description

  The present invention relates to a current detection device that detects a current flowing in a power transmission path such as a bus bar.

  A vehicle such as a hybrid vehicle or an electric vehicle is often equipped with a current detection device that detects a current flowing through a bus bar connected to a battery. As such a current detection device, a magnetic proportional current detection device or a magnetic balance current detection device may be employed.

  For example, as disclosed in Patent Document 1, a magnetic proportional type or magnetic balance type current detection device includes a magnetic core and a magnetoelectric conversion element (magnetic sensitive element). The magnetic core is a generally ring-shaped magnetic body formed in a series surrounding both sides of a hollow portion where both ends face each other through a gap portion and the bus bar passes therethrough. The hollow portion of the magnetic body is a space (current detection space) through which a current to be detected passes.

  In addition, the magnetoelectric conversion element is disposed in the gap portion of the magnetic core, detects a magnetic flux that changes according to a current flowing through a power transmission path such as a bus bar disposed through the hollow portion, and electrically detects the magnetic flux detection signal. It is an element that outputs as a signal. As the magnetoelectric conversion element, a Hall element is usually adopted.

  As shown in Patent Document 1, in a current detection device, a magnetic core and a magnetoelectric conversion element are often held in a fixed positional relationship by an insulating casing. This housing positions a plurality of components constituting the current detection device in a fixed positional relationship. Note that the casing is generally made of an insulating resin member.

  In the conventional current detection device, a support portion for positioning the magnetic core and the magnetoelectric conversion element is formed in the casing. For example, in the current detection device disclosed in Patent Document 1, the support portion of the magnetic core is a hollow portion of the casing that has a shape along each of the outer peripheral surface and the inner peripheral surface of the magnetic core.

  Further, in the current detection device disclosed in Patent Document 1, an element mounting portion that surrounds the periphery of the magnetic detection portion of the magnetoelectric conversion element in the gap portion of the magnetic core is a support portion of the magnetoelectric conversion element. Usually, the magnetoelectric conversion element is mounted on an electronic substrate together with a signal amplifier circuit and the like. The electronic board is screwed to a screw seat provided in a part of the housing.

JP 2009-128116 A

  By the way, in the current detection device shown in Patent Document 1, after the magnetic detection part of the magnetoelectric conversion element is fixed to the element mounting part of the housing, the lead terminal extending from the magnetic detection part of the magnetoelectric conversion element is an electronic It needs to be connected to the board. In this case, the step of mounting the electronic component on the electronic substrate is divided before and after the operation of fixing the magnetoelectric conversion element to the housing.

  That is, when the magnetic detection part of the magnetoelectric conversion element is fixed to the element mounting part of the casing, the step of mounting the electronic component on the electronic substrate includes the step of mounting the electronic component other than the magnetoelectric conversion element on the electronic substrate, The process is divided into a step of mounting the magnetoelectric conversion element fixed to the body on the electronic substrate. As described above, when the mounting process of the electronic component is divided with another process interposed therebetween, the manufacturing process becomes complicated.

  On the other hand, it is also conceivable to position the magnetic detection part of the magnetoelectric conversion element in the gap part of the magnetic core by positioning the electronic substrate on which the magnetoelectric conversion element is mounted. In this case, a plurality of through holes formed in the electronic substrate, a plurality of screws passed through the through holes, and a plurality of screw seats in the housing in which the screw passing through the through hole of the electronic substrate is tightened are formed on the electronic substrate. Configure the fixed part.

  However, the fixing position of the electronic substrate is likely to vary depending on the dimensional tolerance of the through hole of the electronic substrate and the screw seat of the housing constituting the fixing portion of the electronic substrate. Therefore, when the magnetoelectric conversion element is positioned by positioning the electronic substrate, the position of the magnetic detection unit of the magnetoelectric conversion element in the gap portion of the magnetic core is likely to vary. As a result, a large variation in current detection sensitivity is likely to occur, and this variation adversely affects detection sensitivity adjustment in the current detection device.

  According to the present invention, in the current detection device, the magnetoelectric conversion element can be positioned in the gap portion of the magnetic core while suppressing variations in current detection sensitivity, and an electronic component including the magnetoelectric conversion element can be easily mounted on the electronic substrate. It is intended to be implemented.

The current detection device according to the present invention includes the following components.
(1) The first component is a magnetic core made of a magnetic material, both ends of which face each other via a gap portion, and are formed in a series surrounding the periphery of the hollow portion.
(2) The second component is an electronic substrate mounted in a state where a magnetoelectric conversion element for detecting magnetic flux in the gap portion stands.
(3) The third component is made of an insulating material, and supports the magnetic core and the electronic substrate in a reference state in which the magnetic detection portion of the magnetoelectric conversion element is located in the gap portion of the magnetic core. It is an insulating housing to accommodate.
(4) The fourth component is a first screw and a second screw for fixing the electronic substrate to the insulating housing.
(5) A fifth component is a portion of the insulating casing where a screw hole into which the first screw is tightened is formed, and the gap of the magnetic core supported by the insulating casing It is the 1st screw seat provided in the position which follows a plane which passes along a section and intersects perpendicularly to the direction where the both ends of the magnetic core counter.
(6) A sixth component is a second screw seat which is a portion in the insulating housing where a screw hole into which the second screw is tightened is formed.
(7) The seventh component is a first through hole having a shape in which the first screw penetrates without play at a position facing the first screw seat in the electronic substrate in the reference state. It is the 1st screw penetration part which is a part in which is formed.
(8) The eighth component is a direction along a straight line where the second screw passes through the center of the first through hole at a position facing the second screw seat in the electronic substrate in the reference state. It is the 2nd screw penetration part which is the part in which the 2nd through-hole of the shape which penetrates with the play of this was formed.

  Further, in the current detection device according to the present invention, the second screw seat is more preferably the first screw seat than the distance from the first screw seat to the mounting position of the magnetoelectric conversion element on the electronic substrate in the reference state. It is desirable to be provided at a position away from the screw seat.

  In the present invention, the magnetoelectric conversion element is positioned in the gap portion of the magnetic core by fixing the electronic substrate on which the magnetoelectric conversion element is mounted with screws at two locations. Therefore, after all electronic components are mounted on the electronic substrate, the electronic substrate can be attached to the insulating housing.

  That is, unlike the prior art, the process of mounting the electronic component on the electronic board need not be divided across the process of fixing the electronic board to the insulating housing. As a result, an electronic component including the magnetoelectric conversion element can be easily mounted on the electronic substrate, and the manufacturing process of the current detection device is simplified.

  Further, in the current detection device according to the present invention, the first through hole in the electronic board is a hole in which the first screw penetrates without play, that is, along the contour of the outer peripheral surface of the first screw. Shaped hole. On the other hand, the second through hole is a hole having a shape in which the second screw penetrates with play in a direction along a straight line passing through the center of the first through hole. That is, the dimensional tolerance of the fixing structure of the electronic substrate is offset by the play of the second through hole in the electronic substrate. Therefore, a situation in which the electronic board cannot be screwed due to the dimensional tolerance of the electronic board fixing structure is avoided.

  In addition, the variation in the position of the magnetoelectric conversion element caused by the dimensional tolerance of the fixing structure of the electronic board is an arc whose center is the first screw seat and whose radius is the distance between the first screw seat and the mounting position of the magnetoelectric conversion element. The arc is formed along the direction in which both ends of the magnetic core face each other, that is, along the direction of the detected magnetic flux.

  In the current detection device, the current detection sensitivity depends on the variation in the direction of the magnetoelectric conversion element with respect to the direction of the detected magnetic flux in the gap portion of the magnetic core, and the variation in the position of the magnetoelectric conversion element in the direction orthogonal to the direction of the detected magnetic flux. It is greatly affected. On the other hand, the variation in the position of the magnetoelectric transducer in the direction of the detected magnetic flux in the gap portion of the magnetic core (the direction in which both ends of the magnetic core are opposed) has little influence on the current detection sensitivity.

  In the current detection device according to the present invention, the first screw seat is provided at a position along a plane that passes through the gap portion of the magnetic core and is orthogonal to the direction in which both ends of the magnetic core are opposed. Therefore, the variation in the position of the magnetoelectric conversion element caused by the dimensional tolerance of the fixing structure of the electronic substrate mainly occurs in the direction of the detected magnetic flux. That is, variations in the direction of the magnetoelectric transducer with respect to the direction of the detected magnetic flux and variations in the position of the magnetoelectric transducer in the direction orthogonal to the direction of the detected magnetic flux are unlikely to occur.

  Therefore, by employing the current detection device according to the present invention, it is possible to position the magnetoelectric conversion element in the gap portion of the magnetic core while suppressing variations in current detection sensitivity.

1 is an exploded side view of a current detection device 1 according to an embodiment of the present invention. It is the front view and side view of the electric current detection apparatus 1 of the state from which the cover member of the insulated housing was removed. It is a top view, a front view, a bottom view, and a side view of a magnetoelectric conversion element provided in the current detection device 1. It is a front view of a part of electronic board with which current detection device 1 is provided. It is a front view of a part of main body case of an insulation case with which current detection device 1 is provided, and a magnetic core stored in it. It is a front view of a part of main body case of an insulation case with which current detection device 1 is provided, a magnetic core stored in it, and an electronic substrate. It is the figure where the dispersion | variation in the position of a Hall element in the gap part of a magnetic body core was typically shown. It is a main part case of the insulation housing | casing with which the electric current detection apparatus which concerns on the application example 1A is equipped, the magnetic body accommodated in it, and the front view of a part of electronic board.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example embodying the present invention, and is not an example of limiting the technical scope of the present invention.

  Hereinafter, the configuration of the current detection device 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. The current detection device 1 is a device that detects a current flowing through a bus bar that electrically connects a battery and a device such as a motor in a vehicle such as an electric vehicle or a hybrid vehicle. As shown in FIG. 1, the current detection device 1 includes a magnetic core 10, a Hall element 20, an insulating housing 40, an electronic substrate 50, a first screw 61 and a second screw 62.

  The Hall element 20 is mounted on the electronic substrate 50. The insulating housing 40 is constituted by a main body case 41 and a lid member 42.

  2A and 2B are a front view and a side view, respectively, of the current detection device 1 with the lid member 42 of the insulating housing 40 removed. 3A is a plan view of the Hall element 20, FIG. 3B is a front view of the Hall element 20, FIG. 3C is a bottom view of the Hall element 20, and FIG. 3 is a side view of the element 20. FIG.

<Magnetic core>
The magnetic core 10 is a member made of a magnetic material such as ferrite or silicon steel. The magnetic core 10 has a shape in which both end portions 13 are opposed to each other via a gap portion 12 of about several millimeters, and are formed in a series around the hollow portion 11. That is, the magnetic core 10 is formed in an annular shape together with the narrow gap portion 12.

  In the present embodiment, the magnetic core 10 is formed in a generally rectangular ring surrounding the rectangular hollow part 11 with rounded corners together with the gap part 12. Note that the magnetic core 10 may be formed in an annular shape surrounding the circular hollow portion 11 together with the gap portion 12.

  A power transmission path 30 such as a bus bar through which a detection target current flows is disposed through the hollow portion 11 of the magnetic core 10. In addition, in FIG. 1, the power transmission path 30 is drawn with the virtual line (two-dot chain line).

<Hall element (magnetoelectric conversion element)>
The Hall element 20 is a sensor that detects a magnetic flux in the gap portion 12 of the magnetic core 10. In the present embodiment, the Hall element 20 is a lead wire type IC including a magnetic detection unit 21 that is a main body portion of the element and a plurality of lead terminals 22 protruding from the bottom surface of the magnetic detection unit 21. The plurality of lead terminals 22 include a power input terminal and a detection signal output terminal. The plurality of lead terminals 22 are fixed to the wiring pattern of the electronic substrate 50 with solder.

  The magnetic detection unit 21 of the Hall element 20 is disposed in the gap portion 12 of the magnetic core 10. In this state, the Hall element 20 detects a magnetic flux that changes in accordance with the current passing through the hollow portion 11 of the magnetic core 10 and outputs a magnetic flux detection signal as an electrical signal. The Hall element 20 is an example of a magnetoelectric conversion element.

  The Hall element 20 detects the magnetic flux passing through the detection center portion 20P, which is a predetermined portion in the magnetic detection unit 21, along a predetermined direction with the highest sensitivity. Hereinafter, a straight line through which the magnetic flux detected with the highest sensitivity by the Hall element 20 passes is referred to as a reference straight line L21. In general, the reference straight line L <b> 21 is a straight line that passes through substantially the center of the magnetic detection unit 21 and is orthogonal to the front and back surfaces of the magnetic detection unit 21.

  In the current detection device 1, the detection center portion 20 </ b> P of the magnetic detection unit 21 is positioned at the center point 12 </ b> C of the gap portion 12 of the magnetic core 10, and the reference straight line L <b> 21 of the magnetic detection unit 21 is opposed to the magnetic core 10. An ideal arrangement state of the magnetic detection unit 21 is a state where the gap detection unit 21 overlaps the gap center line L11 that is a straight line connecting the centers of the projection surfaces of the both end portions 13.

<Electronic board>
The electronic board 50 is a printed circuit board on which the Hall element 20 is mounted at the lead terminal 22 portion. In addition to the Hall element 20, a circuit that performs a process such as amplification on a magnetic flux detection signal output from the Hall element 20 and a connector 51 are mounted on the electronic substrate 50. The Hall element 20 is mounted on the electronic substrate 50 in a standing state by fixing the lead terminal 22 portion to the electronic substrate 50.

  The connector 51 is a component to which a mating connector provided on an electric wire (not shown) is connected. Further, the electronic board 50 is provided with a circuit that electrically connects the lead terminal 22 of the Hall element 20 and the terminal of the connector 51. For example, the electronic board 50 amplifies the signal supplied from the outside via the electric wire and the connector 51 to the lead terminal 22 of the Hall element 20 and the detection signal of the Hall element 20, and the amplified signal Is output to the terminal of the connector 51. Thereby, the current detection device 1 can output a current detection signal to an external circuit such as an electronic control unit through the electric wire with a connector connected to the connector 51.

  Further, the electronic substrate 50 includes a first screw penetration part 521 through which the first screw 61 penetrates and a second screw penetration part 522 through which the second screw 62 penetrates. In the current detection device 1, the first screw 61 and the second screw 62 are screws for fixing the electronic substrate 50 to the insulating housing 40.

  FIG. 4 is a front view of a region including the portion where the Hall element 20 is mounted on the electronic substrate 50, the first screw penetration portion 521, and the second screw penetration portion 522.

  The 1st screw penetration part 521 is a part in which the 1st penetration hole of the shape which the 1st screw 61 penetrates without play is formed. That is, the through hole (first through hole) of the first screw through portion 521 is a hole having a shape along the contour of the outer peripheral surface of the shaft portion of the first screw 61.

  “Play” means a gap between the intentionally set screw and the edge of the through hole, and a slight gap that is unavoidably generated due to the manufacturing precision of each component is unavoidable. It is not included in "play" here.

  As shown in FIG. 4, the through hole of the first screw through portion 521 passes through the mounting position P50 of the Hall element 20 on the electronic substrate 50 and is on a straight line L51 orthogonal to the reference straight line L21 of the Hall element 20. This is the hole where the center point P51 is located.

  On the other hand, the second screw penetration portion 522 has a shape in which the second screw 62 penetrates with play in a direction along one straight line L52 passing through the center point P51 of the through hole of the first screw penetration portion 521. This is the portion where the second through hole is formed. Accordingly, the through hole (second through hole) of the second screw through part 522 has a direction along the straight line L52 passing through the center point P51 of the through hole (first through hole) of the first screw through part 521. A long hole in the longitudinal direction.

  The center point P52 of the through hole of the second screw penetration part 522 is located on a straight line L52 passing through the center point P51 of the through hole of the first screw penetration part 521. In the present embodiment, the through hole (second through hole) of the second screw through part 522 has play in the direction perpendicular to the straight line L52 with respect to the shaft part of the second screw 62. Absent. That is, the through hole of the second screw penetrating portion 522 is a long hole having a shape in which the second screw 62 penetrates with play only in the direction along the straight line L52.

<Insulated housing>
The insulating housing 40 is made of an insulating material, and is a member that supports the magnetic core 10 and the electronic substrate 50 on which the Hall element 20 is mounted in a fixed positional relationship and accommodates them. More specifically, the insulating housing 40 accommodates the magnetic core 10 and the electronic substrate 50 while supporting the magnetic core 10 and the electronic substrate 50 in a state where the magnetic detection unit 21 of the Hall element 20 is positioned in the gap portion 12 of the magnetic core 10. In the following description, a state in which the magnetic detection unit 21 of the Hall element 20 is positioned in the gap 12 of the magnetic core 10 is referred to as a reference state.

  The insulating housing 40 includes two members: a main body case 41 and a lid member 42 attached to the main body case 41. Each of the main body case 41 and the lid member 42 is an integrally molded member made of an insulating resin such as polyamide (PA), polypropylene (PP), or ABS resin.

  The body case 41 is formed in a box shape having an opening, and the lid member 42 closes the opening of the body case 41 by being attached to the body case 41. The main body case 41 and the lid member 42 are formed with a current passage hole 45 that is a through hole through which the power transmission path 30 is passed.

  Further, the lid member 42 sandwiches the magnetic core 10 and the electronic substrate 50 with respect to the main body case 41 that supports the magnetic core 10 and the electronic substrate 50, and closes the opening of the main body case 41. Attached to.

  The main body case 41 and the lid member 42 are provided with lock mechanisms 47 and 48 for holding them in a combined state. The lock mechanisms 47 and 48 shown in FIG. 1 include a claw portion 47 formed to project from the side surface of the main body case 41 and an annular frame portion 48 formed on the side of the lid member 42. When the claw portion 47 of the main body case 41 is fitted into the hole formed by the frame portion 48 of the lid member 42, the main body case 41 and the lid member 42 are held in a state where they are combined.

  As shown in FIG. 2, the main body case 41 and the lid member 42 (insulating housing 40) support the magnetic core 10 and the electronic substrate 50 in a fixed positional relationship with the connector 51 exposed to the outside. The magnetic core 10, the Hall element 20, and the electronic substrate 50 are accommodated. Further, in a state in which the electronic substrate 50 is accommodated between the main body case 41 and the lid member 42, the connector 51 mounted on the electronic substrate 50 is in a state in which the connector 51 is fitted in the chipped portion 46 formed in the main body case 41. Retained.

  As shown in FIG. 5, a core support portion 43 that supports the magnetic core 10 is formed on the inner side surface of the main body case 41 so as to protrude. The core support portion 43 includes a plurality of protrusions, and the plurality of protrusions support the magnetic core 10 by sandwiching a part of the magnetic core 10.

  Furthermore, a movement restricting portion 44 that restricts the movement of the magnetic core 10 supported by the core support portion 43 is formed upright on the inner side surface of the main body case 41. The movement restricting portion 44 restricts the movement of the magnetic core 10 by fitting into the gap portion 12 of the magnetic core 10 supported by the core support portion 43.

  The magnetic core 10 shown in FIG. 5 is positioned by the core support portion 43 and the movement restricting portion 44 of the insulating housing 40.

  In addition, a first screw seat 461 into which the first screw 61 is tightened and a second screw seat 462 into which the second screw 62 is screwed are formed on the inner surface of the main body case 41 in the insulating housing 40. Has been.

  The first screw seat 461 is a part of the main body case 41 and is a portion in which a screw hole 460 into which the first screw 61 is tightened is formed. The first screw seat 461 passes through the gap portion 12 of the magnetic core 10 supported by the main body case 41, and is located at a position along a plane F1 orthogonal to the direction in which both end portions 13 of the magnetic core 10 face each other. Is provided. That is, the center P41 of the screw hole 460 of the first screw seat 461 is located on the plane F1.

  Note that the direction in which both end portions 13 of the magnetic core 10 face each other can be said to be a direction parallel to the gap center line L11 connecting the centers of the projection surfaces of the opposite end portions 13 in the magnetic core 10.

  A plane F1 serving as a reference for the position of the first screw seat 461 passes through the center 12C of the gap portion 12 in the magnetic core 10 supported by the main body case 41, and both end portions 13 of the magnetic core 10 face each other. A plane orthogonal to the direction is desirable. However, even if the plane F1 is slightly deviated from the center 12C of the gap portion 12 in the magnetic core 10, it suffices if the plane F1 is located within a range R1 that passes through the gap portion 12 of the magnetic core 10.

  The second screw seat 462 is a part of the main body case 41 and is a portion in which a screw hole 460 into which the second screw 62 is tightened is formed. The second screw seat 462 is provided at a distance from the first screw seat 461.

  In the example shown in FIG. 5, the position of the center P42 of the screw hole 460 of the second screw seat 462 is on a straight line that passes through the center P41 of the screw hole 460 of the first screw seat 461 and is orthogonal to the plane F1. Is located. However, the position of the center P42 of the screw hole 460 of the second screw seat 462 need not be such a position.

  In the following description, a state where the magnetic detection unit 21 of the Hall element 20 is located in the gap portion 12 of the magnetic core 10 supported by the insulating housing 40 is referred to as a reference state. The insulating housing 40 accommodates the magnetic core 10 and the electronic substrate 50 while supporting them in the reference state.

  As shown in FIG. 2A and FIG. 6, the electronic board 50 is arranged in the reference state, whereby the first screw penetration part 521 and the second screw penetration part 522 formed in the electronic board 50. Each of the through holes and the screw holes 460 of the first screw seat 461 and the second screw seat 462 overlap each other.

  That is, the through hole (first through hole) of the first screw penetration part 521 in the electronic substrate 50 is formed at a position facing the first screw seat 461 in the electronic substrate 50 in the reference state. Similarly, the through hole (second through hole) of the second screw penetration part 522 in the electronic substrate 50 is formed at a position facing the second screw seat 462 in the electronic substrate 50 in the reference state.

  The first screw 61 and the second screw 62 are passed through the through holes of the first screw through portion 521 and the second screw through portion 522 in the electronic substrate 50 in the reference state, and the first screw 61 and the second screw 62 in the main body case 41. The screw holes 460 of the first screw seat 461 and the second screw seat 462 are tightened. Thereby, the magnetic detection unit 21 of the Hall element 20 mounted on the electronic substrate 50 is held in a predetermined position and orientation in the gap 12 of the magnetic core 10.

<Effect>
Hereinafter, the effect of adopting the current detection device 1 will be described with reference to FIG. FIG. 7 is a diagram schematically showing variation in the position of the Hall element 20 in the gap portion 12 of the magnetic core 10.

  In the current detection device 1, the Hall element 20 is positioned in the gap portion 12 of the magnetic core 10 by fixing the electronic substrate 50 on which the Hall element 20 is mounted with screws 61 and 62 at two locations. Therefore, after all electronic components are mounted on the electronic substrate 50, the electronic substrate 50 can be attached to the insulating housing 40.

  That is, unlike the prior art, the process of mounting the electronic component on the electronic board 50 does not need to be divided across the process of fixing the electronic board 50 to the insulating housing 40. As a result, the electronic component including the Hall element 20 can be easily mounted on the electronic substrate 50, and the manufacturing process of the current detection device 1 is simplified.

  In the current detection device 1, the through hole of the first screw penetration part 521 in the electronic substrate 50 is a hole having a shape through which the first screw 61 passes without play. On the other hand, the through hole of the second screw penetration part 522 has a shape in which the second screw 62 penetrates with play in a direction along a straight line L52 passing through the center point P51 of the through hole of the first screw penetration part 521. It is a hole. That is, the dimensional tolerance of the fixing structure of the electronic substrate 50 is offset by the play of the through hole of the second screw penetration portion 522 in the electronic substrate 50. Therefore, a situation in which the electronic board 50 cannot be screwed due to the dimensional tolerance of the fixing structure of the electronic board 50 is avoided.

  Also, the variation in the position of the Hall element 20 caused by the dimensional tolerance of the fixing structure of the electronic substrate 50 is centered on the first screw seat 461 and the first screw seat 461 and the Hall element 20 as shown in FIG. It occurs along an arc L1 whose radius is the distance from the mounting position P50. The arc L1 is generally an arc along the direction in which both end portions 13 of the magnetic core 10 face each other, that is, the direction of the detected magnetic flux.

  In the current detection device 1, the current detection sensitivity is based on variations in the orientation of the Hall element 20 with respect to the direction of the detected magnetic flux in the gap portion 12 of the magnetic core 10 and the position of the Hall element 20 in the direction orthogonal to the direction of the detected magnetic flux. It is greatly affected by variations in On the other hand, the variation in the position of the Hall element 20 in the direction of the detected magnetic flux in the gap portion 12 of the magnetic core 10 (the direction in which both end portions 13 of the magnetic core 10 face each other) has little influence on the current detection sensitivity.

  In the current detection device 1, the first screw seat 461 is provided at a position along a plane F <b> 1 that passes through the gap portion 12 of the magnetic core 10 and that is perpendicular to the direction in which both end portions 13 of the magnetic core 10 face each other. . Therefore, the variation in the position of the Hall element 20 caused by the dimensional tolerance of the fixing structure of the electronic substrate 50 mainly occurs in the direction of the detected magnetic flux.

  In other words, in the current detection device 1, variations in the orientation of the Hall element 20 with respect to the direction of the detected magnetic flux and variations in the position of the Hall element 20 in the direction orthogonal to the direction of the detected magnetic flux are unlikely to occur. Further, the larger the distance D2 from the first screw seat 461 to the second screw seat 462, the smaller the ratio of the variation amount of the position of the Hall element 20 to the dimensional tolerance ΔD generated in the second screw seat 462 portion. .

  Therefore, by employing the current detection device 1, the Hall element 20 can be positioned in the gap portion 12 of the magnetic core 10 while suppressing variations in current detection sensitivity.

<Application example>
FIG. 8 is a front view of a part of the main body case 41 of the insulating housing 40 provided in the current detection device 1 </ b> A according to the application example, the magnetic core 10 accommodated therein, and the electronic substrate 50. In FIG. 8, the same components as those shown in FIGS. 1 to 7 are denoted by the same reference numerals.

  The current detection device 1A has the same structure as the current detection device 1 shown in FIGS. However, in the current detection device 1A, the second screw seat 462 is closer to the first screw seat 461 than the distance D1 from the first screw seat 461 to the mounting position P50 of the Hall element 20 on the electronic substrate 50 in the reference state. It is provided at a remote location.

  In other words, in the current detection device 1A, the distance D2 from the first screw seat 461 to the second screw seat 462 is from the first screw seat 461 to the mounting position P50 of the Hall element 20 on the electronic substrate 50 in the reference state. It is larger than the distance D1.

  By employing the current detection device 1A as shown in FIG. 8, the ratio of the variation amount of the position of the Hall element 20 to the dimensional tolerance ΔD generated in the second screw seat 462 is further reduced. As a result, variation in current detection sensitivity can be further reduced.

<Others>
In the embodiment shown above, the through hole of the first screw through portion 521 has a circular shape with a diameter corresponding to the diameter of the shaft portion of the first screw 61. However, the through hole of the first screw penetration part 521 may be formed in another shape that allows the first screw 61 to penetrate without play.

  For example, it cannot be considered that the through hole of the first screw through portion 521 is a polygon circumscribing the shaft portion of the first screw 61. Similarly, the through hole of the second screw penetration part 522 may be a rectangular long hole whose longitudinal direction is along the straight line L52 passing through the center point P51 of the through hole of the first screw penetration part 521. It's not unthinkable.

DESCRIPTION OF SYMBOLS 1,1A Current detection apparatus 10 Magnetic body core 11 Hollow part of magnetic body core 12 Gap part of magnetic body core 12C Center point of gap part 13 End part of magnetic body core 20 Hall element 20P Detection center part of Hall element 21 Hall element Magnetic sensing part 22 Hall element lead terminal 30 Power transmission path 31 Through part 32 Terminal part 32z Through hole 40 Insulating housing 41 Body case 42 Lid member 43 Core support part 44 Movement restricting part 45 Current passage hole 46 Lack part 47 Claw part (Lock mechanism)
48 Frame (locking mechanism)
DESCRIPTION OF SYMBOLS 50 Electronic board 51 Connector 61 1st screw 62 2nd screw 460 Screw hole 461 1st screw seat 462 2nd screw seat 521 1st screw penetration part 522 2nd screw penetration part F1 plane L1 arc L11 gap Center line L21 Reference straight line P50 Hall element mounting position

Claims (2)

A magnetic core made of a magnetic material, both ends of which are opposed to each other through a gap portion, and surrounds the periphery of the hollow portion;
An electronic substrate mounted in a state where a magnetoelectric conversion element for detecting magnetic flux in the gap portion stands;
An electric current comprising an insulating casing made of an insulating material and configured to support and hold the magnetic core and the electronic substrate in a reference state where the magnetic detection unit of the magnetoelectric conversion element is positioned in the gap portion of the magnetic core A detection device,
A first screw and a second screw for fixing the electronic substrate to the insulating housing;
The insulating housing is a portion in which a screw hole into which the first screw is tightened is formed, and both ends of the magnetic core pass through the gap portion of the magnetic core supported by the insulating housing. A first screw seat provided at a position along a plane orthogonal to the facing direction;
A second screw seat that is a portion in which the screw hole in which the second screw is tightened is formed in the insulating housing;
In the electronic substrate in the reference state, a first through hole having a shape in which the first screw penetrates without play at a position facing the first screw seat. Screw penetrations,
In the electronic substrate in the reference state, the second screw penetrates with play in a direction along a straight line passing through the center of the first through hole at a position facing the second screw seat. And a second screw penetrating portion that is a portion in which the second through hole is formed.   The second screw seat is provided at a position farther from the first screw seat than a distance from the first screw seat to a mounting position of the magnetoelectric conversion element on the electronic substrate in the reference state. The current detection device according to claim 1.

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