JP2012247197A - Current detector and magnetic core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize both miniaturization of a magnetic core and suppression of deterioration in detection accuracy resulting from a noise magnetic force line in a magnetic flux detector such as an on-vehicle current detector.SOLUTION: A current detector 1 comprises a magnetic core 10 molded by sintering powder made of magnetic material, and a bus bar 30 for detecting current. The magnetic core 10 has flange parts 13 formed at both ends so as to serially extend outside over the whole periphery thereof. The bus bar 30 for detecting current is made of a conductor formed with a penetration part 31 which penetrates a hollow part 11 of the magnetic core 10 in a first direction of current passage, and terminal parts 32 which are continuous with both sides respectively in the first direction with respect to the penetration part 31. A width D5 of the terminal part 32 is formed wider than a maximum width D3 of the hollow part 11, and a minimum width D4 of the outline in a cross section of the penetration part 31 is formed wider than a thickness D6 of the terminal part 32. The magnetic core 10, the bus bar 30 for detecting current and a hall element 20 are held without contacting each other by an insulating case 40.

Description

  The present invention relates to a current detection device that detects a current flowing in a bus bar and a magnetic core used in the current detection device.

  An electric 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, Patent Document 1, Patent Document 2, and Patent Document 3 include a magnetic proportional method or a magnetic balance method current detection device, which includes a magnetic core and a magnetoelectric conversion 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 the conventional current detection device, the magnetic core has a structure in which a plurality of thin plate-like members that are substantially ring-shaped and made of a magnetic material are laminated via an adhesive. Hereinafter, the magnetic core having such a structure is referred to as a laminated type magnetic core.

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

JP-A-10-104279 JP 2006-166528 A JP 2009-58451 A

  By the way, devices that generate a relatively strong magnetic field such as a high-voltage power line and an inverter circuit connected to a battery for driving a motor are mounted on the electric vehicle. When the magnetic field lines resulting from such a device are directly incident on the magnetoelectric conversion element of the current detection device, the current detection accuracy deteriorates. On the other hand, in-vehicle current detection devices are required to be further miniaturized, and accordingly, the magnetic core is required to be miniaturized.

  However, when a small magnetic core is adopted, the cross-sectional area of the magnetic core is reduced, and therefore, noise magnetic field lines that are not detection targets are likely to be directly incident on the magnetoelectric conversion element disposed in the gap portion of the magnetic core. . That is, the conventional current detection device has a problem that it is difficult to achieve both reduction in size of the magnetic core and suppression of deterioration in detection accuracy caused by noise magnetic field lines.

  In the conventional current detection device, since the flat bus bar is inserted through the hollow portion of the magnetic core, the maximum width (diameter) of the hollow portion of the magnetic core is larger than the width of the bus bar. It needs to be formed in a size. On the other hand, in an electric vehicle, a hybrid vehicle, and the like, a wide bus bar is being adopted in order to prevent excessive heat generation of the bus bar as the current flowing through the bus bar increases.

  Therefore, the conventional current detection device has a problem that, as the bus bar width increases, a large magnetic core proportional to the bus bar width is required, and the device becomes larger. In particular, when the magnetic core is in an annular shape, an elliptical shape, or a rectangular shape in which the ratio of the vertical dimension to the horizontal dimension is 1 or 1, the larger the bus bar width, the more wasted space in the hollow part of the magnetic core. Increase. In addition, when a bus bar in which only the portion disposed in the hollow portion of the magnetic core is narrowed is employed, there is a problem that the narrowed portion generates excessive heat.

  An object of the present invention is to achieve both reduction in size of a magnetic core and suppression of deterioration in detection accuracy caused by noise magnetic field lines in a magnetic flux detection device such as an on-vehicle current detection device.

The current detection device according to the present invention includes the following components.
(1) Both ends of the first component are opposed to each other via a gap, and are formed in a series around the periphery of the hollow part. Magnetic core.
(2) A 2nd component is a magnetoelectric conversion element which is arrange | positioned at the said gap part of a magnetic body core, and detects the magnetic flux which changes according to the electric current which passes the hollow part of a magnetic body core.

  In the current detection device according to the present invention, it is conceivable that the magnetic core is a member formed by sintering powder made of a magnetic material.

It is also conceivable that the current detection device according to the present invention further includes the following components.
(3) The third component includes a penetrating portion that penetrates the hollow portion of the magnetic core, and a connecting end of each of the front and rear stages of the current transmission path that are connected to both sides of the penetrating portion in the direction penetrating the hollow portion. This is a current detection bus bar made of a conductor formed with a terminal portion to be connected, wherein the width of the terminal portion is larger than the width of the hollow portion.

  Further, in the current detection device according to the present invention, the flange portion of the magnetic core has a structure in which a plurality of layers made of different kinds of magnetic materials are laminated from the inside to the outside in a direction other than the direction of the gap portion. It is possible.

  Further, the present invention may be understood as an invention of a magnetic core for magnetic flux detection employed in a magnetic flux detection device such as a magnetic proportional method or magnetic balance method current detection device. That is, the magnetic core for magnetic flux detection according to the present invention is formed in a series of both ends facing each other through a gap portion, surrounding the periphery of the hollow portion, and continuously projecting outward at both ends over the entire periphery. A buttocks is formed.

  According to the present invention, even when a small magnetic core is employed, the noise magnetic field lines directed to the magnetoelectric conversion element arranged in the gap portion of the magnetic core are not incident on the magnetic core before entering the magnetoelectric conversion element. The light enters the ridges formed at both ends. Further, the noise magnetic field lines incident on the collar part are radiated from the magnetic core by changing the path by propagating along the magnetic core. Therefore, the phenomenon that noise magnetic field lines that are not detection targets are directly incident on the magnetoelectric conversion element disposed in the gap portion of the magnetic core is alleviated, and deterioration in detection accuracy due to the noise magnetic field lines is suppressed.

  By the way, even if the magnetic core has a ridge at both ends thereof, the noise magnetic field lines directed to the magnetoelectric conversion element along the direction orthogonal to the direction in which both ends of the magnetic core face each other or the direction close thereto are magnetoelectrically converted. It is directly incident on the element. However, the magnetoelectric conversion element is disposed in the gap portion of the magnetic core in a posture facing both ends of the magnetic core, that is, the direction of the magnetic flux to be detected. In this case, the noise magnetic field lines along the direction orthogonal to the direction in which both ends of the magnetic core face each other or a direction close thereto have little influence on the magnetoelectric conversion element.

  A laminated type magnetic core in which a plurality of plate-like members are laminated is difficult to be formed into an irregular shape having a flange at the end. In addition, the laminated type magnetic core is likely to cause a dimensional error due to a positional relationship error between a plurality of plate-like members and a dimensional error of the adhesive layer. Further, the smaller the size of the magnetic core, the greater the influence of the dimensional error of the magnetic core, and the more serious the detection accuracy of the magnetic flux (current) becomes.

  On the other hand, a sintered type magnetic core formed by sintering powder made of a magnetic material can be easily formed into a deformed shape having a flange at the end. Furthermore, even if the sintered type magnetic core is downsized, dimensional errors are less likely to occur. Therefore, if a sintered magnetic core is employed in the current detection device according to the present invention, a current detection error caused by a dimensional error of the magnetic core is unlikely to occur. Furthermore, the sintered type magnetic core is superior to the laminated type magnetic core in that the number of manufacturing steps and cost can be reduced.

  Hereinafter, when the current detection device according to the present invention includes a current detection bus bar, the direction in which the current detection bus bar passes through the hollow portion of the magnetic core (current passing direction) is referred to as a first direction. Further, in the current detection bus bar, the width direction and the thickness direction of the terminal portion connected before and after the through portion penetrating the hollow portion of the magnetic core are referred to as a second direction and a third direction, respectively.

  In the case where the current detection device according to the present invention includes a current detection bus bar, in the current detection bus bar, the penetrating portion that penetrates the hollow portion of the magnetic core has a cross-sectional contour as compared with the terminal portion that is continuous in the front and back. Is formed smaller than the width (maximum width) of the terminal portion. That is, the outline shape of the cross-section of the penetrating portion is constricted in the second direction with respect to the terminal portion. As a result, a relatively small magnetic core can be employed in relation to the width of the bus bar, and the entire apparatus including the magnetic core can be reduced in size. In addition, since both ends of the current detection bus bar are terminal portions, the current detection bus bar in a state of penetrating through the hollow portion of the magnetic core is connected to the pre-stage and post-stage bus bars laid in advance. Is possible.

  In the current detection bus bar, the central portion (penetrating portion) penetrating the hollow portion of the magnetic core can be formed in a shape other than a flat plate shape, such as a rod shape such as a round bar or a square bar, or a cylindrical shape. Therefore, the penetrating portion can be formed with a larger cross-sectional area under the constraint that the maximum width is smaller than the width of the hollow portion of the magnetic core as compared with the flat bus bar. Therefore, even when a relatively small magnetic core is employed, excessive heat generation of the current detection bus bar can be prevented.

  Moreover, the magnetic body has different characteristics of the magnetic lines of force that easily propagate depending on the type of the material. Therefore, if the collar portion of the magnetic core has a structure in which a plurality of layers made of different types of magnetic materials are laminated, shielding performance against various noise magnetic field lines having different characteristics can be ensured.

It is a disassembled perspective view of the electric current detection apparatus 1 which concerns on embodiment of this invention. 1 is a perspective view of a magnetic core 10 and a Hall element 20 provided in a current detection device 1. FIG. 2 is a cross-sectional view of a flange portion of a magnetic core 10 and a Hall element 20. FIG. FIG. 3 is a three-side view of a current detection bus bar 30 provided in the current detection device 1. 5 is a perspective view schematically showing a manufacturing process of the current detection bus bar 30. FIG. 1 is a plan view of a current detection device 1. FIG. It is a perspective view which shows typically a mode that the electric current detection apparatus 1 is connected with the bus bar laid beforehand.

  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.

  First, the configuration of the current detection device 1 according to the embodiment of the present invention will be described with reference to FIGS. 4A is a plan view, FIG. 4B is a side view, and FIG. 4C is a front view. The current detection device 1 is a device that detects a current flowing in a bus bar that electrically connects a battery and a device such as a motor in 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, a current detection bus bar 30, an insulating housing 40, and an electronic substrate 50.

<Magnetic core>
The magnetic core 10 is a member (magnetic body) formed by sintering powder made of a magnetic material such as permalloy, ferrite, or silicon steel. That is, the magnetic core 10 is a member that is solidified and molded by compressing a solid powder aggregate made of a magnetic material in a mold and further heating it at a temperature lower than the melting point of the magnetic material. It is.

  Further, the magnetic core 10 has a shape in which both ends face each other via a gap portion 12 of about several millimeters and are formed in a series around the periphery of the hollow portion 11. In other words, the magnetic core 10 has a narrow gap portion 12 but is formed in a generally annular shape. The magnetic core 10 in this embodiment is formed in an annular shape surrounding the circular hollow portion 11.

  Further, at both ends of the magnetic core 10, flanges 13 are formed so as to protrude outward in series over the entire periphery. Although the contour shape of the collar part 13 shown by FIG.1 and FIG.2 is a rectangle, it is also considered that the contour shape of the collar part 13 is other shapes, such as a polygon other than a rectangle, circular, or an ellipse.

  Further, as shown in FIG. 3, the flange portion 13 of the magnetic core 10 includes a first layer 131 and a second layer 132 made of different magnetic materials in directions other than the gap portion 12 direction. Are stacked from the inside to the outside. For example, it is conceivable that the first layer 131 is made of PB permalloy and the second layer 132 is made of PC permalloy.

  In the present embodiment, the inner first layer 131 in the flange portion 13 is made of the same magnetic material as the magnetic material that forms the base portion other than the flange portion 13 in the magnetic core 10. That is, the base portion of the magnetic core 10 and the first layer 131 of the flange portion 13 are portions formed integrally by solidifying powder made of the same magnetic material in a series of sintering processes.

  On the other hand, the second layer 132 of the flange portion 13 is a portion formed on the surface of the first layer 131 in the member after the member including the base and the first layer 131 of the flange portion 13 is formed. is there. As a method of forming the second layer 132 of the collar part 13, for example, a powder made of a magnetic material is applied to a portion of the first layer 131 in a member composed of a base and the first layer 131 of the collar part 13. A method of further adding a sintering step is conceivable. It is also conceivable to apply a magnetic material plating to the portion of the first layer 131 in the member composed of the base and the first layer 131 of the flange 13.

  As will be described later, a Hall element 20 is disposed in the gap portion 12 of the magnetic core 10, and the Hall element 20 detects a magnetic flux generated in a ring shape along the magnetic core 10. That is, the magnetic core 10 is a magnetic body for detecting magnetic flux.

<Hall element (magnetoelectric conversion element)>
The Hall element 20 is disposed in the gap portion 12 of the magnetic core 10, detects a magnetic flux that changes according to a current passing through the hollow portion 11 of the magnetic core 10, and outputs a magnetic flux detection signal as an electric signal. It is an example of a conversion element.

  In the gap portion 12 of the magnetic core 10, the Hall element 20 is disposed in a posture facing the direction in which both ends of the magnetic core 10 face each other, that is, the direction of the magnetic flux to be detected. More specifically, the Hall element 20 has front and back surfaces that are parallel to both end surfaces of the magnetic core 10, and the magnetism receiving portions located substantially in the center of the Hall element 20 have both end surfaces of the magnetic core 10. Are arranged in a posture positioned on a straight line connecting the centers of the portions excluding the collar portion 13.

  The Hall element 20 arranged in the gap portion 12 in the above posture detects the magnetic flux along the direction in which both ends of the magnetic core 10 face each other with high sensitivity, but is perpendicular to the direction in which both ends of the magnetic core face each other. Or the magnetic flux along the direction close | similar to it is hardly detected.

<Electronic board>
The electronic board 50 is a board on which a circuit connected to the terminal 21 of the Hall element 20 and a connector 51 for connecting the circuit and other external circuits are mounted. Accordingly, the connector 51 is electrically connected to the hall element 20. The circuit mounted on the electronic substrate 50 is, for example, a circuit that amplifies a magnetic flux detection signal output from the Hall element 20. The hall element 20 is connected to an external circuit through an electronic substrate 50 including a connector 51.

<Bus bar for current detection>
The current detection bus bar 30 is a conductor made of a metal such as copper, and is a part of the bus bar that electrically connects the battery and the electrical equipment. That is, a current to be detected flows through the current detection bus bar 30. The current detection bus bar 30 is a member independent of the battery-side bus bar connected in advance to the battery and the device-side bus bar connected in advance to the electrical equipment. The current detection bus bar 30 is connected to the other bus bars (battery side bus bar and device side bus bar) of the front stage and the rear stage where both ends thereof are laid in advance. The current detection bus bar 30 and the other bus bars at the front stage and the rear stage connected thereto form a current transmission path from the battery to the electrical equipment. The end portions of the other bus bars are an example of connection ends of conductors at the front and rear stages of the current detection bus bar 30 in the current transmission path.

  As shown in FIG. 1, the current detection bus bar 30 is made of a member in which both end portions of a rod-shaped conductor that penetrates the hollow portion 11 of the magnetic core 10 are processed. In the current detection bus bar 30, the processed both end portions are terminal portions 32 connected to the connection ends of the front and rear stages of the current transmission path. That is, the current detection bus bar 30 is generally formed of a rod-shaped through portion 31 that occupies a certain range in the central portion, and a terminal portion formed on both sides of the through portion 31 in the direction of passing through the hollow portion 11. 32. The member which consists of a conductor which has 32.

  The penetration part 31 is a part that penetrates the hollow part 11 of the magnetic core 10 along the current passing direction. The current passing direction is the thickness direction of the magnetic core 10, the axial direction of the cylinder when the annular magnetic core 10 is regarded as a cylinder, and further on the surface formed by the annular magnetic core 10. It is also an orthogonal direction. In each figure, the current passing direction is indicated as the X-axis direction. In the following description, the current passing direction (X-axis direction) is referred to as a first direction.

  The terminal part 32 in this embodiment is flat form. Moreover, the penetration part 31 in the bus bar 30 for electric current detection is formed in rod shapes, such as column shape or elliptical column shape, for example. In each figure, the width direction and the thickness direction of the flat terminal portion 32 are described as a Y-axis direction and a Z-axis direction, respectively. In the following description, the width direction (Y-axis direction) and the thickness direction (Z-axis direction) of the flat terminal portion 32 are referred to as a second direction and a third direction, respectively.

  FIG. 5 is a perspective view schematically showing a manufacturing process of the current detection bus bar 30. The current detection bus bar 30 has a structure in which both end portions of a rod-shaped metal member 30X are processed. The minimum width of the cross-sectional contour of the rod-shaped metal member 30 </ b> X is formed to be larger than the gap height D <b> 2 that is the distance between both ends of the magnetic core 10. Since the metal member 30X shown in FIG. 5 has a cylindrical shape, the minimum width of the cross-sectional contour of the metal member 30X is the diameter of the metal member 30X.

  More specifically, the current detecting bus bar 30 has a plate-like portion formed by pressing using a press machine 60 or the like in a certain range at both ends of the rod-shaped metal member 30X that penetrates the hollow portion 11 of the magnetic core 10. It is the member which has the structure crushed by. At this time, at least one of both ends of the rod-shaped metal member 30X is pressed into a flat plate shape after the rod-shaped metal member 30X is inserted into the hollow portion 11 of the magnetic core 10.

  That is, in the process of manufacturing the current detection device 1, the process of manufacturing the current detection bus bar 30 is executed by the following procedure, for example. [1] First, a penetrating step for penetrating the rod-shaped metal member 30X through the hollow portion 11 of the magnetic core 10 is executed. [2] Next, a first pressing step is performed in which one end of the rod-shaped metal member 30X is crushed into a flat plate having a width wider than that of the other portion by the press machine 60 or the like. [3] Finally, a second pressing step is performed in which the other end of the rod-shaped metal member 30X is crushed into a flat plate having a width wider than that of the other portion by the press machine 60 or the like.

  In the above manufacturing process, the [1] penetration process may be performed before one or both of the [2] first pressing process and the [3] second pressing process are performed. For example, first, [1] the penetration process may be performed, and then [2] the first pressing process and [3] the second pressing process may be performed simultaneously. In addition, [2] the first pressing process may be performed first, then [1] the penetration process may be performed, and finally [3] the second pressing process may be performed.

  Then, the portions of both ends crushed into a flat plate form a flat terminal portion 32 in the current detection bus bar 30, and a bar-shaped portion between them forms a through portion 31 of the current detection bus bar 30. .

  The metal member 30X shown in FIG. 5 is a cylindrical member, and the through portion 31 of the current detection bus bar 30 manufactured by processing both ends of the metal member 30X is cylindrical. In addition, it is also conceivable that the rod-shaped metal member 30X has an elliptical bar shape with an elliptical cross section or a square bar shape with a rectangular cross section. Further, the rod-shaped metal member 30X may have a rod shape whose cross section is a polygon other than a quadrangle.

  The cross-sectional shape of the metal member 30 </ b> X, that is, the cross-sectional shape of the penetrating portion 31 is desirably a shape similar to the contour shape of the hollow portion 11 of the magnetic core 10. For example, when N is an integer of 3 or more, when the contour shape of the hollow portion 11 of the magnetic core 10 is a regular N square, it is preferable that the shape of the metal member 30X is a regular N prism. Moreover, when the outline shape of the hollow part 11 of the magnetic body core 10 is circular, if the shape of the metal member 30X is a cylinder, it is suitable. Moreover, when the outline shape of the hollow part 11 of the magnetic body core 10 is an ellipse whose ratio of the major axis to the minor axis is R, the shape of the metal member 30X is the ratio of the major axis to the minor axis in the cross section. It is suitable if is an elliptic cylinder with R.

  In the current detection bus bar 30, the width D <b> 5 of the terminal portion 32 is formed larger than the diameter D <b> 1 (maximum width) of the hollow portion 11. Further, the minimum width D4 of the cross-sectional contour of the penetrating portion 31 is formed larger than the thickness D6 of the terminal portion 32. In other words, the ratio of the vertical dimension and the horizontal dimension of the cross-sectional outline of the penetrating portion 31 is closer to 1 than the ratio of the vertical dimension and the horizontal dimension of the cross-section of the flat terminal portion 32. In addition, when the penetration part 31 is cylindrical, the minimum width D4 and the maximum width D3 in the outline of the cross section of the penetration part 31 are the same. Moreover, that the ratio is close to 1 includes that the ratio is 1.

  Further, in the current detection bus bar 30, the minimum width D4 of the cross-sectional contour of the through portion 31 is formed to be larger than the gap height D2 that is the distance between both ends of the magnetic core 10. Moreover, as described above, the width D5 of the terminal portion 32 is larger than the diameter D1 (maximum width) of the hollow portion 11 of the magnetic core 10. Therefore, the magnetic core 10 cannot be mounted on the through-hole 31 of the current detection bus bar 30 manufactured in advance. Accordingly, after a set of the magnetic core 10 and the current detection bus bar 30 penetrating through the hollow portion 11 of the magnetic core 10 is made, the current detection bus bar 30 is connected to the other bus bars in the front and rear stages. Connected.

  Therefore, the terminal portion 32 is formed with a through hole 32Z for screwing, whereby the terminal portion 32 is connected to the other bus bars at the front and rear stages by screws. FIG. 7 is a perspective view schematically showing a state in which the terminal portion 32 in the current detection device 1 is connected to the other bus bars 9 in the front stage and the rear stage that are laid in advance by screws 8.

  In FIG. 7, illustration of the insulating housing 40 is omitted for convenience. As shown in FIG. 7, the connection end connected to the terminal portion 32 in the other bus bar 9 has, for example, a structure as a terminal block, and a hole 9 </ b> A for screwing is formed. In addition, the terminal part 32 in the current detection bus bar 30 has other structures such as a fitting mechanism with other bus bars 9 in addition to the flat terminal part 32 in which the through holes 32Z for screwing are formed. Is also possible.

<Insulated housing>
The insulating housing 40 is made of an insulator and is a member that holds the magnetic core 10, the Hall element 20, the current detection bus bar 30, and the electronic substrate 50, and is a main body case 41 and a lid member 42 that is attached to the main body case 41. Including. Each of the main body case 41 and the lid member 42 is an integrally formed member made of an insulating resin such as polyamide (PA), polypropylene (PP), polybutylene terephthalate (PBT), 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 is formed with a first holding portion 43 and a second holding portion 44 that protrude on the inner surface thereof. The main body case 41 includes the first holding portion 43 and the second holding portion 44, the magnetic core 10, the current detection bus bar 30 penetrating the hollow portion 11, and the Hall element 20 disposed in the gap portion 12. Are held in a state where they are not in contact with each other.

  More specifically, the first holding portion 43 is fitted into the gap between the magnetic core 10 and the through portion 31 of the current detection bus bar 30 that penetrates the hollow portion 11, thereby detecting the current detection of the magnetic core 10. The bus bars 30 are held in a state where they do not contact each other. Further, the second holding portion 44 fits into the gap between the magnetic core 10 and the Hall element 20 disposed in the gap portion 12, thereby bringing the magnetic core 10 and the Hall element 20 into contact with each other. Hold in a state that does not.

  In addition, a recess 49 into which the flange 13 of the magnetic core 10 held by the first holding part 43 and the second holding part 44 is fitted is formed on the inner surface of the main body case 41.

  The main body case 41 and the lid member 42 are formed with slit-like terminal portion through holes 45 into which the terminal portions 32 at both ends of the current detection bus bar 30 are inserted from the inside to the outside. In a state where one terminal portion 32 of the current detection bus bar 30 penetrating through the hollow portion 11 of the magnetic core 10 is passed through the terminal portion through hole 45 of the main body case 41, the first holding portion 43 of the main body case 41 and The second holding unit 44 holds the magnetic core 10, the Hall element 20, and the current detection bus bar 30.

  The lid member 42 is attached to the main body case 41 holding the magnetic core 10, the Hall element 20 and the current detection bus bar 30 so as to close the opening of the main body case 41 while sandwiching the electronic substrate 50. At this time, the other terminal portion 32 of the current detection bus bar 30 is passed from the inside to the outside with respect to the terminal portion through hole 45 of the lid member 42. Further, since the electronic board 50 is sandwiched between the main body case 41 and the lid member 42, the connector 51 mounted on the electronic board 50 is held in a state of being fitted into the chipped portion 46 formed in the main body case 41. Is done.

  Furthermore, the main body case 41 and the lid member 42 are provided with lock mechanisms 47 and 48 that hold 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.

  FIG. 6 is a plan view of the current detection device 1 in a state where the main body case 41 and the lid member 42 are combined. As shown in FIG. 6, the main body case 41 and the lid member 42 (insulating housing 40) include a portion (terminal portion) in which the through hole 32 </ b> Z is formed in the terminal portion 32 of the current detection bus bar 30, and the electronic substrate 50. With the connector 51 exposed to the outside, the magnetic core 10, the through-hole 31 of the current detection bus bar 30, and the Hall element 20 are covered and held.

<Effect>
In FIG. 3, an alternate long and short dash line arrow represents a noise magnetic field line that is not a detection target. Even in the case where the small magnetic core 10 is employed in the current detection device 1, as shown in FIG. 3, the noise magnetic field lines toward the Hall element 20 are applied to both ends of the magnetic core 10 before entering the Hall element 20. It is incident on the flange 13 formed in the above. In addition, the noise magnetic force lines incident on the flange 13 are radiated from the magnetic core 10 while changing the path by propagating along the magnetic core 10. Therefore, the phenomenon in which noise magnetic field lines that are not detection targets are directly incident on the Hall element 20 is alleviated, and deterioration in detection accuracy due to the noise magnetic field lines is suppressed.

  In addition, the Hall element 20 is disposed in the gap portion 12 of the magnetic core 10 so as to face the direction in which both ends of the magnetic core 10 face each other, that is, the direction of the magnetic flux to be detected. Therefore, even if a noise magnetic field line along a direction perpendicular to or near the direction in which both ends of the magnetic core 10 face each other directly enters the Hall element 20, the noise magnetic field line has almost no influence on the Hall element 20. do not do.

  Further, if the magnetic core 10 is a sintered type formed by sintering a powder made of a magnetic material, it can be easily formed into a deformed shape having the flange 13 at the end. Furthermore, even when the sintered magnetic core 10 is downsized, dimensional errors are less likely to occur. Therefore, if the sintered magnetic core 10 is employed in the current detection device 1, a current detection error due to a dimensional error of the magnetic core 10 is unlikely to occur. Further, the sintered type magnetic core 10 is superior in that the number of manufacturing steps and cost can be reduced as compared with the laminated type magnetic core.

  Further, in the current detection bus bar 30 of the current detection device 1, the through portion 31 is formed such that the maximum width D3 of the contour of the cross section is smaller than the width D5 (maximum width) of the terminal portion. That is, the outline shape of the cross section of the through portion 31 is constricted in the second direction with respect to the terminal portion 32. As a result, in the current detection device 1, the relatively small magnetic core 10 can be employed in relation to the widths of the other bus bars in the front and rear stages, and the entire apparatus including the magnetic core 10 can be downsized.

  In the current detection bus bar 30, the penetrating part 31 that penetrates the hollow part 11 of the magnetic core 10 is formed in a shape other than a flat plate such as a round bar or a square bar. Therefore, the through-hole 31 is formed with a larger cross-sectional area under the constraint that the maximum width thereof is smaller than the diameter D1 (width) of the hollow portion 11 of the magnetic core 10 compared to the flat bus bar. be able to. Therefore, even when a relatively small magnetic core 10 is employed, excessive heat generation of the current detection bus bar 30 can be prevented.

  Moreover, if the cross-sectional shape of the penetration part 31 of the current detection bus bar 30 is similar to the outline shape of the hollow part 11 of the magnetic core 10, the gap between the penetration part 31 and the magnetic core 10 is further reduced. be able to. As a result, the apparatus can be reduced in size by adopting a smaller magnetic core 10.

  Further, in the current detection bus bar 30, the cross-sectional shape of the through portion 31 is formed such that the minimum width D 4 is larger than the thickness D 6 (minimum width) of the terminal portion 32. In the current detection bus bar 30 having a structure in which both ends of the rod-shaped metal member 30 </ b> X are flattened, the cross-sectional area of the conductor in the through portion 31 is greater than or equal to the cross-sectional area of the conductor in the terminal portion 32. Therefore, excessive heat generation in the penetration part 31 can be prevented. In addition, since the terminal part 32 is a part in which the overall heat capacity combined with the connecting screw 8 and the other bus bar 9 pressed against each other is increased, the problem of heat generation due to the presence of the hole 32Y does not occur.

  Further, in the current detecting bus bar 30 having a structure in which both end portions of the rod-shaped metal member 30X are crushed into a flat plate shape, the hollow portion 11 is inserted after the rod-shaped metal member 30X is inserted into the hollow portion 11 of the magnetic core 10. The flat terminal portion 32 having a width wider than the width D1 can be formed. That is, it is not necessary to pass the through portion 31 through the gap portion 12 of the magnetic core 10. Therefore, the current detection bus bar 30 in which the cross-sectional width D3 (diameter) of the bar-shaped through portion 31 is larger than the gap height D2 in the magnetic core 10 can be easily manufactured.

  In order to increase the current detection sensitivity, it is desirable to reduce the gap height D2 and to reduce the gap between the Hall element 20 disposed in the gap portion 12 and both ends of the magnetic core 10.

  In the current detection device 1, the magnetic core 10, the Hall element 20, and the current detection bus bar 30 are other than the portion (terminal portion) of the through hole 32 </ b> Z of the terminal portion 32 and the connector 51 that should be exposed. Is held in a predetermined positional relationship by an insulating housing 40 covering the. Thereby, the operation | work which attaches the electric current detection apparatus 1 with respect to the bus bar 9 laid beforehand becomes easy.

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In the current detection device 1, it is also conceivable that the flange portion 13 of the magnetic core 10 is composed of only the first layer 131. It is also conceivable that the flange 13 of the magnetic core 10 has a structure in which three or more layers made of different kinds of magnetic materials are laminated.

  Further, in the current detection device 1, the two flat terminal portions 32 of the current detection bus bar 30 may be formed along non-parallel surfaces.

  It is also conceivable that the terminal portion 32 is not flat. For example, it is conceivable that the terminal portion 32 is a portion processed thicker than the other portions by upsetting at the end of the rod-shaped metal member 30X. In this case, the terminal portion 32 which is a thickly processed portion is formed with a screw hole into which the screw 8 for coupling with the connection end of the other bus bar at the front stage and the rear stage is tightened.

  In the flow detection bus bar 30, a bent portion may be formed between the penetrating portion 31 and the terminal portion 32. In addition, in the current detection bus bar 30, a portion of a certain range at both ends of the cylindrical metal member penetrating the hollow portion 11 of the magnetic core 10 was crushed into a flat plate shape by pressing using a press machine 60 or the like. It may be a member having a structure. At that time, at least one of both ends of the cylindrical metal member is pressed into a flat plate shape after the cylindrical metal member is inserted into the hollow portion 11 of the magnetic core 10. In this case, the portions at both ends crushed into a flat plate form the terminal portion 32 in the current detection bus bar 30, and the cylindrical portion between them forms the through portion 31 of the current detection bus bar 30.

DESCRIPTION OF SYMBOLS 1 Current detection apparatus 8 Screw 9 Other bus bar 9A Hole 10 Magnetic body core 11 Hollow part of magnetic body core 12 Gap part of magnetic body core 13 Grow part of magnetic body core 20 Hall element 21 Terminal 30 Current detection bus bar 30X Metal member 31 Current detection bus bar penetration part 32 Current detection bus bar terminal part 32Z through hole 40 Insulating housing 41 Main body case 42 Lid member 43 First holding part 44 Second holding part 45 Slit hole 46 Notch part 47 Claw part (Lock mechanism)
48 Frame (locking mechanism)
49 Dimple 50 Electronic board 51 Connector 60 Press

Claims (5)

A magnetic core in which both ends are opposed to each other through a gap part, and are formed in a series surrounding the periphery of the hollow part, and a flange part is formed on the both ends over the entire periphery in series.
A current detection device comprising: a magnetoelectric conversion element that is disposed in the gap portion of the magnetic core and detects a magnetic flux that changes according to a current passing through the hollow portion of the magnetic core.   The current detection device according to claim 1, wherein the magnetic core is a member formed by sintering powder made of a magnetic material.   A penetrating portion that penetrates the hollow portion of the magnetic core, and a terminal portion that is connected to both sides of the penetrating portion in a direction penetrating the hollow portion and is connected to the connection ends of the front and rear stages of the current transmission path. The current detection device according to claim 1, further comprising a current detection bus bar made of a formed conductor and having a width of the terminal portion formed larger than a width of the hollow portion.   The said collar part of the said magnetic body core has a structure where the several layer which consists of a different kind of magnetic material in each direction other than the direction of the said gap part was laminated | stacked from the inner side to the outer side. The current detection device according to any one of the above. A magnetic core for detecting magnetic flux,
Both ends are opposed to each other through a gap portion, and are formed in a series around the periphery of the hollow portion, and a flange portion is formed in the both ends, which extends outward in series over the entire periphery. Body core.

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