JP2011242276A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor capable of facilitating a positioning work of a magnetoelectric transducer while miniaturizing a magnetic core.SOLUTION: A current sensor 10 comprises: a magnetic core 12 that is formed in a ring shape having a gap 22 and provided as surrounding the outer circumference of a conductor, a magnetoelectric transducer 13 that is provided in a gap 22 and detects the magnitude of the current flows through the conductor, and a holder 14 that holds the magnetoelectric transducer 13. Convex portions 23 are formed on each ends of the magnetic core 12 that forms the gap 22 of the magnetic core 12, the convex portions 23 protruding in the direction intersecting the circumferential direction of the ring-shaped magnetic core 12. Engaging portions 32 are formed on the holder 14, the engaging portions 32 positioning the holder 14 with respect to the gap 22 by engaging with the convex portions 23.

Description

  The present invention relates to a current sensor.

  Conventionally, as a current sensor, for example, the one described in Patent Document 1 is known. In this current sensor, a magnetoelectric conversion element is arranged in a gap of a magnetic core having a ring shape having a gap. A conductor is inserted through the ring-shaped portion of the magnetic core. The magnetoelectric transducer detects the magnitude of the current flowing through the conductor by converting the strength of the magnetic field in the gap into a voltage signal.

  The current sensor is disposed in an electric connection box mounted on a vehicle such as an electric vehicle or a hybrid vehicle, for example, and flows through a bus bar (corresponding to a conductor) routed in the electric connection box. May be used to measure the size of

JP 2009-42003 A

  In recent years, miniaturization of electrical junction boxes has been demanded in vehicles. For this reason, downsizing is also required for the current sensor arranged in the electrical junction box. In order to reduce the size of the current sensor, it is effective to make the magnetic core occupying most of the projected area of the current sensor as small as possible.

  However, when the magnetic core is made small, the region where the magnetic flux density is uniform in the gap of the magnetic core becomes narrow. For this reason, there exists a problem that the positioning operation | work of the magnetoelectric conversion element arrange | positioned in a gap will become difficult.

  The present invention has been completed based on the above-described circumstances, and an object thereof is to provide a current sensor that can reduce the size of a magnetic core and facilitate positioning of a magnetoelectric conversion element. To do.

  The present invention is a current sensor, which has a ring shape with a gap and surrounds the outer periphery of a conductor, and a magnetic core disposed in the gap and flowing in the conductor. A magnetoelectric conversion element for detecting the thickness, and a holder for holding the magnetoelectric conversion element, and the magnetic core that forms a gap is formed in a ring shape at both ends of the magnetic core. A convex portion that protrudes in a direction intersecting the circumferential direction of the body core is formed, and an engaging portion that positions the holder with respect to the gap is formed on the holder by engaging the convex portion. Has been.

  According to the present invention, since the convex portions are provided at both ends of the magnetic core forming the gap, the magnetic core as a whole can be formed without narrowing the region where the magnetic flux density is uniform in the gap of the magnetic core. Miniaturization can be achieved.

  Furthermore, according to the present invention, when the convex part of the magnetic core and the engaging part of the holder are engaged, the gap between the core and the holder is formed at both ends of the magnetic core forming the gap. Positioning can be performed accurately. Thereby, positioning of the magnetoelectric conversion element hold | maintained at the holder and the gap of a core can be performed correctly.

As embodiments of the present invention, the following embodiments are preferable.
The holder is preferably formed with a locking claw that protrudes toward the magnetic core and locks to the magnetic core.

  According to said aspect, since it can suppress that a magnetic body core and a holder shift | deviate, positioning of a gap and a magnetoelectric conversion element can be performed reliably.

  It is preferable that the engaging portion is formed to be depressed so as to follow the outer shape of the convex portion.

  According to said aspect, since positioning with a magnetic core and a holder can be performed by uneven | corrugated fitting, the positioning accuracy with a magnetic core and a holder can be improved.

  The holder and the magnetic core are housed in a case, and one of the holder and the case is formed with an engaging convex portion protruding to the other side, and the other of the holder and the case is It is preferable that an engagement concave portion that engages with the engagement convex portion is formed.

  According to said aspect, a holder and a case can be positioned by the uneven | corrugated fitting of an engagement convex part and an engagement recessed part. Thereby, relative positioning of a case, a holder, and a magnetic body core can be performed.

  According to the present invention, the magnetic core can be reduced in size, and the positioning operation of the magnetoelectric conversion element can be easily performed.

1 is an exploded perspective view showing a current sensor according to Embodiment 1 of the present invention. Side view showing holder Main section enlarged view showing the current sensor IV-IV line sectional view in FIG. The principal part expanded sectional view which shows the latching structure of a magnetic body core and a latching claw The principal part expanded sectional view which shows the current sensor which concerns on Embodiment 2. FIG. The principal part expanded sectional view which shows the current sensor which concerns on Embodiment 3. FIG.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. The current sensor 10 according to this embodiment includes a case 11 in which a magnetic core 12, a magnetoelectric conversion element 13, and a holder 14 holding the magnetoelectric conversion element 13 are accommodated. The current sensor 10 is disposed, for example, in an electric connection box (not shown) mounted on an electric vehicle or a hybrid vehicle (not shown), and includes, for example, a battery (not shown) and an inverter (not shown). Detect current flowing between In the following description, the upper direction in FIG.

(Case 11)
The case 11 is made of synthetic resin, and includes a lower case 15 and an upper case 16 that covers the lower case 15 from above. A bus bar insertion hole 18 </ b> A through which a bus bar 17 made of a metal plate (corresponding to a conductor described in claims) is inserted is passed through the bottom plate of the lower case 15.

  The upper case 16 is integrally assembled with the lower case 15 by well-known assembling means such as bolt tightening and elastic engagement between the lock projection and the lock receiving portion. A bus bar insertion hole 18B through which the bus bar 17 is inserted passes through the upper plate of the upper case 16.

  A fitting tube portion 19 to which the holder 14 is assembled is formed on the upper plate of the upper case 16 so as to penetrate the upper plate. On the side wall of the fitting cylinder part 19, an engagement concave part 21 that locks the holder 14 by engaging with the engagement convex part 20 formed on the holder 14 penetrates the side wall of the fitting cylinder part 19. Is formed.

(Magnetic core 12)
The magnetic core 12 is formed by, for example, compressing or compressing a powder made of a magnetic material such as permalloy or ferrite in a mold and then sintering the powder (referred to as a so-called powder core). The magnetic core 12 has a ring shape with a gap 22 and is substantially C-shaped as a whole.

  The magnetic core 12 is disposed at a position where the ring-shaped portion of the magnetic core 12 surrounds the bus bar insertion hole 18 </ b> A of the lower case 15 with respect to the lower case 15. Thereby, the above-mentioned bus bar 17 is inserted in a ring-shaped portion of the magnetic core 12. As a result, the magnetic core 12 is arranged so as to surround the outer periphery of the bus bar 17.

  A gap 22 having a predetermined size is formed in the magnetic core 12. Protrusions 23 projecting in a direction intersecting the circumferential direction of the ring-shaped magnetic core 12 are formed at both ends of the magnetic core 12 forming the gap 22. In the present embodiment, the convex portion 23 is formed to project radially from a portion of the magnetic core 12 different from the end portion. Specifically, the protrusion 23 of the magnetic core 12 according to the present embodiment protrudes in the width direction (up and down direction in FIG. 4) and also protrudes in the thickness direction (up and down direction in FIG. 3). Yes. An escape recess 25 is formed on the bottom plate of the lower case 15 to avoid interference with the protrusion 23 of the magnetic core 12.

(Holder 14)
The holder 14 is made of a synthetic resin and has a substantially rectangular parallelepiped shape. On the upper surface of the holder 14, a fitting recess 28 is formed in which a mating connector 27 connected to the electric wire 26 can be fitted. One end of a connector terminal 29 that can be connected to the mating connector 27 is disposed in the fitting recess 28. The other end of the connector terminal 29 is embedded in the holder 14. An electronic component (not shown) such as an antistatic capacitor is connected to the other end of the connector terminal 29, and the magnetoelectric conversion element 13 is connected to the connector terminal 29.

  As shown in FIG. 2, a magnetoelectric conversion element 13 is provided below the holder 14 so as to protrude downward. The holder 14 and the magnetoelectric conversion element 13 are connected by three lead wires 30. In the figure, the circuit formed in the holder 14 is omitted.

  The holder 14 is formed with a plurality of (four in this embodiment) leg portions 31 protruding downward. The above-described magnetoelectric conversion element 13 is disposed in a space surrounded by the four legs 31. The lower end portion of the leg portion 31 is formed so as to be positioned below the lower surface of the magnetoelectric conversion element 13.

(Engagement structure of magnetic core 12 and holder 14)
As shown in FIG. 1, the holder 14 is assembled to the magnetic core 12 from the direction indicated by the arrow A in FIG. 1. As shown in FIG. 4, in a state where the holder 14 is assembled to the magnetic core 12, the four leg portions 31 are arranged in the vicinity of the gap 22 formed between both end portions of the magnetic core 12. Specifically, the magnetic core 12 is arranged at positions outside the convex portions 23 formed at both ends.

  The shape of the lip of the relief recess 25 formed in the lower case 15 is substantially rectangular. The escape recess 25 is formed to accommodate the four legs 31. In the present embodiment, the lower case 15 and the holder 14 are positioned by the leg portion 31 of the holder 14 being in sliding contact with the corner of the relief recess 25.

  A region of the leg portion 31 that faces the convex portion 23 of the magnetic core 12 serves as an engaging portion 32 that positions the magnetic core 12 and the holder 14 by engaging with the convex portion 23. Thereby, the gap 22 of the magnetic core 12 and the holder 14 are positioned. In the present embodiment, the engaging portion 32 is formed to be depressed on the surface of the leg portion 31 facing the convex portion 23 of the magnetic core 12 so as to follow the outer shape of the convex portion 23.

  As shown in FIG. 5, a locking claw 33 protruding toward the magnetic core 12 is formed at the lower end portion of the leg portion 31. The locking claw 33 comes into contact with the lower end edge of the magnetic core 12 from below. As shown in FIG. 4, the locking claws 33 formed on the four leg portions 31 are locked to the magnetic core 12, so that the magnetic core 12 is moved by the leg portions 31 and the locking claws 33. It is designed to be held from the outside. The lower surface of the locking claw 33 is formed with a tapered surface 34 that tapers toward the tip.

(Manufacturing process)
Then, an example of the manufacturing process of the current sensor 10 according to the present embodiment will be described. First, the magnetic core 12 is placed on the bottom wall of the lower case 15. At this time, the magnetic core 12 is arranged so that the convex portion 23 of the magnetic core 12 is located in the escape concave portion 25 of the lower case 15. Next, the leg part 31 of the holder 14 is assembled | attached to the magnetic body core 12 from upper direction (direction shown by the arrow A in FIG. 1).

  More specifically, first, the locking claw 33 formed at the lower end portion of the leg portion 31 of the holder 14 contacts the magnetic core 12 from above. At this time, the leg 31 is expanded and deformed by the sliding contact between the tapered surface 34 of the locking claw 33 and the upper surface of the magnetic core 12. When the holder 14 is further pushed down, the leg portion 31 is restored and deformed, and the locking claw 33 goes around the lower surface of the magnetic core 12 and comes into contact with the magnetic core 12 from below. Thereby, the magnetic core 12 is held by the four legs 31 so as to be held from the outside.

  At this time, the engaging portion 32 formed in the region of the leg portion 31 facing the protruding portion 23 of the magnetic core 12 and the protruding portion 23 of the magnetic core 12 engage with each other. And the holder 14 are positioned.

  On the other hand, the lower case 15 and the holder 14 are positioned by the outer surface of the leg portion 31 of the holder 14 coming into contact with the inner surface of the relief recess 25 of the lower case 15.

  Next, the upper case 16 is assembled to the lower case 15 from above. At this time, the holder 14 is inserted into the fitting cylinder portion 19 of the upper case 16. Then, the engagement convex portion 20 formed on the outer surface of the holder 14 engages in the engagement concave portion 21 formed in the fitting cylinder portion 19 of the upper case 16, so that the holder 14, the upper case 16, Is positioned.

  Subsequently, the mating connector 27 connected to the electric wire 26 is fitted into the fitting recess 28 of the holder 14 from above. Thereafter, the bus bar 17 is inserted into the bus bar insertion holes 18 </ b> A and 18 </ b> B formed in the lower case 15 and the upper case 16. Thereby, the current sensor 10 is completed.

(Function, effect)
If the size of the magnetic core 12 is reduced as a whole in order to reduce the size of the current sensor 10, the region where the magnetic flux density is uniform in the gap 22 of the magnetic core 12 becomes narrow. For this reason, there is a concern that the positioning operation of the magnetoelectric conversion element 13 disposed in the gap 22 becomes difficult.

  Therefore, in the present embodiment, the convex portions 23 are provided at both ends of the magnetic core 12 that forms the gap 22. As a result, the magnetic core 12 as a whole can be reduced in size without narrowing the region where the magnetic flux density in the gap 22 of the magnetic core 12 is uniform.

  Furthermore, in this embodiment, the convex part 23 which protrudes in the direction which cross | intersects the circumferential direction of the magnetic body core 12 which makes | forms a ring shape in the both ends of the magnetic body core 12 which forms the gap 22 among the magnetic body cores 12. On the other hand, the holder 14 is configured to have an engaging portion 32 for positioning the holder 14 with respect to the gap 22 by engaging with the convex portion 23. As a result, the convex portion 23 of the magnetic core 12 and the engaging portion 32 of the holder 14 engage with each other, so that the core gap 22 and the holder 14 are connected to each other at both ends of the magnetic core 12 forming the gap 22. Can be accurately aligned.

  As a result, the current sensor 10 can be reduced in size, and the magnetoelectric conversion element 13 held by the holder 14 and the core gap 22 can be accurately positioned.

  Further, in the present embodiment, the holder 14 is formed with a locking claw 33 that protrudes toward the magnetic core 12 and is locked to the magnetic core 12. Thereby, since it can suppress that the magnetic body core 12 and the holder 14 shift | deviate, positioning of the gap 22 and the magnetoelectric conversion element 13 can be performed reliably.

  Further, in the present embodiment, the engaging portion 32 is formed to be depressed so as to follow the outer shape of the convex portion 23. Thereby, since the magnetic core 12 and the holder 14 can be positioned by the concave-convex fitting, the positioning accuracy between the magnetic core 12 and the holder 14 can be improved.

  Further, in the present embodiment, the engagement convex portion 20 formed on the outer surface of the holder 14 is adapted to engage in the engagement concave portion 21 formed in the fitting cylinder portion 19 of the upper case 16. Thereby, the holder 14 and the upper case 16 can be positioned by the concave and convex fitting between the engaging convex portion 20 and the engaging concave portion 21. Thereby, relative positioning of case 11, holder 14, and magnetic body core 12 can be performed.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG. Three leg portions 31 are formed on the holder 14. The leg part 41 located on the upper side in FIG. 3 has a rectangular cross section. A region of the leg portion 41 that faces the magnetic core 12 is an engaging portion 42. The engaging portion 42 contributes to the positioning of the magnetic core 12 and the holder 14 by engaging with both the convex portions 23 formed at both ends of the magnetic core 12.

  A locking claw 43 that protrudes toward the magnetic core 12 is formed at the lower end of the leg 41. The locking claws 43 are also locked to both the convex portions 23 formed at both ends of the magnetic core 12.

  Since the configuration other than the above is substantially the same as that of the first embodiment, the same members are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, since one engaging portion 42 is configured to engage both the two convex portions 23, the positioning accuracy between the holder 14 and the magnetic core 12 can be improved. .

  Moreover, since the one latching claw 43 becomes a structure latched with both the two convex parts 23, the positioning accuracy of the holder 14 and the magnetic body core 12 can be improved further.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG. In the present embodiment, the holder 14 is formed with two leg portions 31. The leg portions 31 are formed diagonally on the bottom surface of the holder 14 having a substantially rectangular parallelepiped shape.

  Since the configuration other than the above is substantially the same as that of the first embodiment, the same members are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, since the amount of the synthetic resin material constituting the holder 14 can be reduced compared to the case where the four leg portions 31 are formed, the manufacturing cost can be reduced.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) The lower case 15 and the upper case 16 of the current sensor 10 may also serve as the lower case 15 and the upper case 16 of the electrical junction box in which the current sensor 10 is accommodated. In this case, the bus bar insertion hole 18B of the lower case 15 may be omitted.
(2) In the present embodiment, the engaging convex portion 20 is formed on the holder 14 and the engaging concave portion 21 is formed on the upper case 16. However, the engaging concave portion is formed on the holder 14 and the upper case 16 is formed on the upper case 16. It is good also as a structure which forms an engagement convex part.
(3) The magnetic core 12 may be formed by punching a plate made of a magnetic material such as permalloy. In this case, the protrusion 23 of the magnetic core 12 has a shape protruding in the width direction of the magnetic core 12 and does not protrude in the thickness direction.
(4) The locking claw 33 of the holder 14 may be omitted.
(5) In the present embodiment, the mating connector 27 connected to the electric wire 26 is fitted into the fitting recess 28 of the holder 14, whereby the electric wire 26 and the holder 14 are connected. However, the configuration is not limited to this, and the electric wire 26 may be directly led out from the holder 14 without using the mating connector 27.
(6) In the present embodiment, the holder 14 and the magnetoelectric conversion element 13 are connected by the three lead wires 30, but may be configured by being connected by two or four or more lead wires. Good.

DESCRIPTION OF SYMBOLS 10 ... Current sensor 11 ... Case 12 ... Magnetic body core 13 ... Magnetoelectric conversion element 14 ... Holder 15 ... Lower case 16 ... Upper case 17 ... Bus bar (conductor)
20 ... engaging convex part 21 ... engaging concave part 22 ... gap 23 ... convex part 32 ... engaging part 33 ... locking claw

Claims (4)

A magnetic core arranged in a ring shape having a gap and surrounding an outer periphery of the conductor; a magnetoelectric conversion element arranged in the gap and detecting the magnitude of a current flowing through the conductor; A holder for holding a magnetoelectric conversion element,
Of the magnetic core, convex portions projecting in a direction intersecting with a circumferential direction of the magnetic core having a ring shape are formed at both ends of the magnetic core forming the gap,
An electric current sensor in which the holder is formed with an engaging portion for positioning the holder with respect to the gap by engaging with the convex portion. The current sensor according to claim 1, wherein the holder is formed with a locking claw that protrudes toward the magnetic core and is locked to the magnetic core. The current sensor according to claim 1, wherein the engaging portion is formed to be depressed so as to follow the outer shape of the convex portion. The holder and the magnetic core are housed in a case,
One of the holder and the case is formed with an engaging convex portion protruding to the other side,
The current sensor according to any one of claims 1 to 3, wherein an engagement recess that engages with the engagement protrusion is formed on the other of the holder and the case.

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