JP6547123B2 - Coil component and method of manufacturing the same - Google Patents

Description

  The present invention relates to a coil component used in various electronic devices and a method of manufacturing the same.

  In recent years, electronic control of drive systems and control systems of automobiles has been increasingly promoted, and a large number of electronic control devices have come to be mounted on a single automobile, and further miniaturization and high reliability of electronic control devices are desired. It is rare.

  Also, coil components used in these electronic control devices are required to have high vibration resistance and impact resistance that can be surface mounted for miniaturization and are required for automotive parts.

  Such a conventional coil component is, as shown in FIG. 11, a magnetic core 1 made of a magnetic material, a coil 2 embedded inside the magnetic core 1 and a terminal portion projecting from the side of the magnetic core, and The flat plate terminal 3 is projected from the side surface to the outside of the magnetic core 1 and connected to the end of the coil 2. The side surface of the magnetic core 1 is provided with a groove 4 for storing the terminal portion of the coil 2 and the flat plate terminal 3 The coil component is configured by bending the end portion of the coil 2 protruding from the side surface of the magnetic core 1 and the flat terminal 3 toward the bottom side of the magnetic core 1 along the side surface of the magnetic core 1.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP, 2011-249770, A

  Since these coil parts mounted on electronic control devices of automobiles may be mounted in the vicinity of the engine due to the increase in the number of mounted electronic control devices, further improvement of vibration resistance and impact resistance is required. Not only is it becoming necessary, but also there is a need to cope with increasing the current by increasing the performance and functionality of electronic control devices.

  However, in the above-described conventional configuration, when torsion or bending stress is applied to the flat terminal due to more severe vibration or impact in the vicinity of the engine, since the terminal is flat, the torsion or bending stress remains as it is. There is a fear that the power may be transmitted to the connection part with the terminal part of the above, or to the base part of the terminal part of the coil.

  Further, since the groove is provided on the side of the magnetic core to store the flat terminal, the depth of the groove is set by adding the clearance to the thickness of the flat terminal and the end portion of the coil. When lateral vibration is applied to the coil component, it is possible for the flat terminal to move in the groove, and stress may be transmitted to the end portion of the coil due to repeated vibration.

  Then, by providing the groove, there is a problem that the cross-sectional area of the magnetic core is reduced, and it is difficult to improve the magnetic characteristics against the increase in current.

  It is an object of the present invention to provide a coil component capable of both improving the vibration resistance and impact resistance of the coil component and coping with the increase in current.

  In order to solve the above problems, the present invention solves the above problems by using a magnetic core made of powder magnetic material mixed with a binder and pressure molded, a coil element embedded in the magnetic core and having an end projecting from the side of the core, and a coil element The terminal is connected with the end of the core and bent from the side to the bottom of the magnetic core, and the terminal has a recess recessed in the direction opposite to the side of the core and a convex on the back A stepped portion is provided, and the end of the coil element is connected to the bottom of the recess.

  With the above configuration, the terminal is provided on the side surface of the magnetic core with a recessed portion recessed in the opposite direction to the side surface of the magnetic core and a stepped portion having a convex portion formed on the back surface thereof. Because the stepped portion surrounds the connecting portion between the end of the coil element and the terminal and is three-dimensionally configured, the connecting portion between the end of the coil element and the terminal is twisted or bent. It is possible to prevent damage to the connection portion between the end of the coil element and the terminal and the end of the end of the coil element by suppressing this.

  Also, unlike the conventional coil component, the groove for housing the terminal is not formed on the side surface of the magnetic core, the cross-sectional area of the magnetic core is not reduced, and the magnetic characteristic is improved against the increase in current of the coil component. It can be made easy.

  As described above, according to the present invention, it is possible to obtain a coil component capable of both improving the vibration resistance and impact resistance of the coil component and dealing with a large current.

An exploded perspective view of a coil component according to an embodiment of the present invention The transparent perspective view of the coil component in one embodiment of the present invention Sectional view along the line A-A of the welded portion between the terminal and the end of the coil element in FIG. 2 Sectional drawing of the BB line of the welding part of the terminal in FIG. 2, and the edge part of a coil element The figure explaining the manufacturing method of the coil component in one embodiment of the present invention The figure explaining the manufacturing method of the coil component in one embodiment of the present invention The figure explaining the manufacturing method of the coil component in one embodiment of the present invention The figure explaining the manufacturing method of the coil component in one embodiment of the present invention The figure explaining the manufacturing method of the coil component in one embodiment of the present invention The figure explaining the manufacturing method of the coil component in one embodiment of the present invention A view showing a conventional coil component

  Hereinafter, a coil component in an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of a coil component in an embodiment of the present invention, and FIG. 2 is a transparent perspective view of the coil component. 3 is a cross-sectional view taken along the line A-A of the welded portion between the terminal and the end of the coil element in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line B-B of the welded portion between the terminal and the end of the coil element in FIG. FIG.

  The coil component in one embodiment of the present invention is formed by spirally winding a magnetic core 11 having a rectangular cross section obtained by pressing a mixture of metal magnetic powder and a binder and pressing the magnetic core 11. The coil element 12 is formed by processing a metal plate and having one end embedded in the side surface of the magnetic core 11 and the other end protruding from the magnetic core 11 At the same time, the end 12a of the coil element protruding from the side surface of the magnetic core 11 is connected and fixed, and the pair of terminals 13 bent along the bottom surface from the side surface of the magnetic core 11 is provided.

The magnetic core 11 is a plurality of green compacts 19 obtained by mixing a binder containing a thermosetting resin and a metal magnetic powder in a state where the thermosetting resin is not completely cured and pressing the mixture at about 1 ton / cm ^2. Is repress-formed so as to sandwich the coil element 12, and the coil element 12 is covered with the green compact 19 and heat-treated and molded so that the thermosetting resin is completely cured.

At this time, repressing is performed at a pressure of about 5 tons / cm ² which is larger than pressure forming, and the thickness of the green compact 19 is thin after repressing forming than before repressing forming. And the molding density is increased. Two green compacts 19 are provided, and one green compact 19 is formed in a prismatic shape in which a storage portion for completely housing the coil element 12 is formed, and the other green compact 19 is covered on one green compact 19. The end 12 a of the coil element and the terminal 13 have a lid-like shape and project from the interface between the two green compacts 19.

  The coil element 12 is formed by winding an insulation coated copper wire having a diameter of 0.3 mm in a coil shape, and the end 12a of the coil element protruding from the magnetic core 11 peels off the insulation coating and has a thickness of about 0 It is pressed to a flat shape of .2 mm.

  The terminal 13 is formed by punching a metal plate having a thickness of about 0.15 mm, and has a U-shaped katakana shape in which the protrusions 20 are integrally formed at both ends on the magnetic core 11 side. 20 are embedded in the magnetic core 11 and fixed to the magnetic core 11.

  When the terminal 13 is bent along the side surface of the magnetic core 11 between the projecting portions 20 of the terminal 13, a concave portion recessed from the flat portion 21 of the terminal in the opposite direction to the side surface of the magnetic core 11 on the side surface of the magnetic core 11 14 and a stepped portion 18 which is pressed so as to form a convex portion 15 on the back surface thereof.

  The stepped portion 18 is formed to surround a region including a portion overlapping with the end 12a of the coil element, and the end 12a of the coil element along the extending direction of the end 12a of the coil element in the width direction. The recess 14 is formed to have a width larger than the width of the coil and opposed in the lengthwise direction to be longer than the end 12a of the coil element, and the depth of the recess 14 formed by the stepped portion 18 is It is formed with a depth equal to or greater than the thickness dimension or diameter dimension of the end 12a, and in the present embodiment, the depth of the recess 14 is 0.2 mm.

  Then, the end 12a of the coil element is accommodated in the recess 14 formed by the stepped portion 18, the end 12a of the coil element is overlapped on the bottom 16 of the recess 14 and resistance-welded and fixed partially. There is.

  Of the terminals 13, portions protruding from the magnetic core 11 are solder dipped as needed to coat the surface with the solder, and the coil component is configured by bending the side surfaces of the magnetic core 11 along the bottom surface.

  As described above, the coil component according to the present embodiment has the concave portion 14 recessed from the flat portion 21 of the terminal in the opposite direction to the side surface of the magnetic core 11 and the convex portion 15 on the back surface thereof. The stepped portion 18 to be formed is provided, and the end 12a of the coil element is fixedly connected to the bottom portion 16 of the recess 14, so the connected portion between the end 12a of the coil element and the terminal 13 is stepped portion 18 In order to form a three-dimensional structure by surrounding it, the stress of twisting or bending applied to the flat portion 21 of the terminal is transmitted to the connecting portion between the end 12a of the coil element and the terminal 13 or the root of the end 12a of the coil element It can be made hard and the vibration resistance and impact resistance of the coil component can be improved.

  This is because, for example, when the coil component is subjected to lateral vibration, the whole of the flat portion 21 of the terminal abuts on the side surface of the magnetic core 11 so that the terminal 13 does not move, and a coil stress is applied to the coil component. When the terminal 13 is subjected to a twisting or bending stress, the step processing portion 18 is three-dimensional so that it is difficult to cause the twisting or bending, so that the stress can be hardly transmitted to the end 12a of the coil element.

  Further, since the recessed portion 14 recessed in the direction opposite to the side surface of the magnetic core 11 and the stepped portion 18 forming the protruding portion 15 on the back surface thereof, a groove for housing a terminal is provided on the side surface of the magnetic core as in a conventional coil component. Since this can be eliminated, the cross-sectional area of the magnetic core 11 does not decrease, and the magnetic characteristics can be easily improved with respect to the increase in current of the coil component.

  Further, in the coil component of the present embodiment, it is desirable to use a copper plate of pure copper as the material of the terminal 13.

  Generally, a phosphor bronze plate excellent in springiness and high in strength is often used for terminals of electronic parts such as coil parts, but in the present embodiment, the stepped portion 18 provided on the terminals 13 is three-dimensional. Since high strength makes it less likely to twist or bend, a copper plate of pure copper, which is a softer material than a phosphor bronze plate, can be employed, and by doing this, pure copper has a higher conductivity than phosphor bronze. Since it is high, the loss of the coil component can be reduced to improve the characteristics against the increase in current.

  The stepped portion 18 may be provided in accordance with the length of the end 12a of the coil element in the longitudinal direction, but extends to the lower edge of the magnetic core 11 in the extending direction of the end 12a of the coil element It is desirable to provide.

  By doing this, the convex portion 15 is formed on the terminal 13 to the lower edge portion of the coil component and becomes three-dimensional, so that the terminal 13 is further prevented from being twisted or bent, and the end of the coil element It is possible to make it difficult for stress to be transmitted to the portion 12a.

  Furthermore, when the coil component is soldered to the mounting substrate (not shown), solder fillets (not shown) of the mounting solder are formed around the convex portions 15 and held three-dimensionally, so that the terminals The strength against twisting and bending stress of 13 can be further increased, and the connection strength between the mounting substrate and the coil component can also be improved.

  In addition, it is desirable that the bottom portion 16 of the recess 14 be provided with a linear protrusion 17 stamped from the back side of the recess 14.

  The projection 17 is a linear shape having a dimension longer than the width of the end 12a of the coil element, and the projection 17 and the end 12a of the coil element are made to intersect and resistance-welded.

  By providing the projections 17 in this manner, a crosspiece is provided between the stepped parts 18 opposed to each other, and the strength of the stepped parts 18 is further improved, and a stress of torsion or bending applied to the terminals 13 It can be made difficult to transmit to the fixed part of the end 12a of the coil element and the terminal 13 or the root part of the end 12a of the coil element. For this reason, it is more preferable to provide the protrusion 17 so as to connect between the stepped portions 18 on both sides of the end 12a of the coil element.

  Furthermore, the provision of the projection 17 can improve the productivity by reducing the deformation of the terminal 13 when the terminal 13 and the end 12a of the coil element are resistance-welded.

  This is because when the end 12a of the coil element is overlapped with the terminal 13 and resistance welding is performed, pressure is applied to the terminal 13 and the end 12a of the coil element with a welding electrode (not shown). A force is easily applied in a direction perpendicular to the extending direction of the end 12a, and the terminal 13 is easily extended in the width direction. As a result, the pressure of the welding electrode causes distortion in the terminal 13 and the position of the projecting portion 20 is shifted in the width direction, which may cause the projecting portion 20 to be caught in the mold when the magnetic core 11 is press-formed.

  On the other hand, as in the present embodiment, by providing the projection 17, the force of spreading in the width direction is absorbed because the projection 17 is softened and easily crushed and deformed during welding. Even if a soft material such as pure copper is used for the terminal 13, the positional deviation of the projection 20 can be reduced, and the projection 20 is pinched by the mold when the magnetic core 11 is press-formed. Can be prevented to improve productivity.

  The shape of the protrusion 17 is such that the shape of the cross section orthogonal to the extension direction of the protrusion 17 becomes thinner from the root to the top of the protrusion 17 such as a triangle, arc or trapezoid. The back side is preferably one that can be dented by embossing. By doing this, the projection 17 can be more easily crushed and deformed.

  And it is preferable to make the protrusion height dimension of the projection part 17 smaller than the depth dimension of the recessed part 14.

  When the height of the top of the protrusion 17 is the same height as the flat portion 21 of the terminal which is the main surface of the terminal 13 having the protrusion 20 formed, the flat portion 21 of the terminal when the protrusion 17 is crushed and deformed. Distortion is likely to be transmitted, but by making the protruding height dimension of the protrusion 17 smaller than the depth dimension of the recess 14, the top of the protrusion 17 is applied to the stepped portion 18, so the protrusion 17 is deformed It is possible to make it difficult to transmit time distortion to the flat portion 21 of the terminal.

  For this reason, it is more preferable to set it as 2/3 or less of the depth dimension of the recessed part 14 more preferably.

  Here, FIG. 2 is a transparent perspective view in which the magnetic core 11 is seen through, and the outline of the powder compact 19 or the magnetic core 11 is indicated by a broken line.

  Next, a method of manufacturing a coil component according to an embodiment of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 5, a copper wire with an insulating coating on the surface is spirally wound to form a coil element 12 in which the lead wire is drawn to the left and right. Thereafter, the insulation coating of the portion to be welded to the terminal 13 of the end 12a of the coil element is peeled off. (Coil part formation process)

  Next, as shown in FIG. 6, a hoop-like terminal 13 is formed by punching a copper plate of pure copper with a die, and the end 12a of the coil element is overlapped on this as shown in FIG. Thus, the coil element 12 is connected to the terminal 13 and fixed. (Welding process)

  It is desirable that the terminal 13 be provided with projecting portions 20 on both sides of a portion overlapping with the end portion 12 a of the coil element so as to form a katakana U-shaped, and be embedded in the magnetic core 11. By so doing, the terminal 13 can be made difficult to come off the core 11 and can be easily bent.

  In addition, when the terminal 13 is bent along the bottom surface from the side surface of the magnetic core 11 in advance, the terminal 13 is flat in a region including a portion overlapping the end 12 a of the coil element on the side surface of the magnetic core 11. The stepped portion 18 is formed by pressing so that the concave portion 14 recessed from the portion 21 in the direction opposite to the side surface of the magnetic core 11 and the convex portion 15 are formed on the back surface thereof.

  The depth of the recess 14 is equal to or larger than the thickness or diameter of the end 12a of the coil element, and the end 12a of the coil element is accommodated in the recess 14 and overlapped with the bottom 16 to be partially melted by resistance and fixed Do.

  When the end 12a of the coil element protrudes beyond the recess 14, it is preferable to press the end 12a of the coil element into a flat shape as shown in FIG. 5 in the coil portion forming step. Further, when the thickness or diameter of the end 12a of the coil element is thin or the like, pressing into a flat shape may be omitted.

  The stepped portion 18 may be provided in accordance with the length of the end 12a of the coil element in the longitudinal direction, but it should be provided up to the lower edge of the core 11 in the extending direction of the end 12a of the coil element. Is more desirable.

  In this case, in particular, in the radius of curvature of the bent portion of the flat portion 21 of the terminal and the stepped portion 18, the radius of curvature on the lower edge side of the magnetic core 11 is R1 (the portion shown as R1 in FIG. 3, FIG. 6) When the radius of curvature of the bent portions on both sides in the extending direction of the end portion 12a of the coil element is R2 (a portion shown as R2 in FIG. 4 and FIG. 6), R1> R2 is desirable, and R1 is 0.1 to 0.1. It is good to make 1.0 mm and R2 0.4 mm or less.

  It is desirable to reduce the radius of curvature of the bent portions of the flat portion 21 and the stepped portion 18 of the terminal in order to obtain strength against twisting and bending in the stepped portion 18. The strength is reduced by increasing the radius of curvature R1 of the bent portion only on the part side.

  By doing this, when the terminal 13 is bent along the bottom surface from the side surface of the magnetic core 11, the edge of the bending from the side surface to the bottom surface of the magnetic core 11 is partially applied to the stepped portion 18. However, the terminal 13 can be easily bent.

  As a result, the variation in the height dimension of the magnetic core 11 due to the variation in pressure forming can be absorbed, and the productivity can be improved.

  Further, at the bottom portion 16 of the recess 14, a linear protrusion 17 embossed from the back side of the recess 14 is provided so as to intersect the end 12 a of the coil element, and the end 12 a of the coil element and the protrusion 17 are intersected It is desirable to make resistance welding while making contact. In this way, the end 12a of the coil element and the projection 17 are properly brought into contact with each other, and the welding current is concentrated on the top of the projection 17, so that resistance welding can be facilitated.

  Further, it is desirable to make the height of projection of the projection 17 from the bottom 16 smaller than the depth of the recess 14 and to be 2/3 or less of the depth of the recess 14. In this way, when resistance welding is performed, it is possible to suppress the protrusion 17 from being easily crushed and deformed and the end 12 a of the coil element being out of the recess 14.

Next, as shown in FIG. 8, the binder containing the thermosetting resin and the metal magnetic powder are mixed in a state where the thermosetting resin is not completely cured, dried and pulverized to obtain a magnetic material. Is pressed at about 1 ton / cm ² to obtain a plurality of green compacts 19 as shown in FIG. 1, and then the coil element 12 and the projecting portion 20 of the terminal 13 are sandwiched to obtain 5 ton / ton. The pressure is repressurized at about cm ² and the coil element 12 is covered with the green compact 19 to form the core 11 of the coil component. The magnetic core 11 is completely cured by heat treating it at about 180 ° C. or higher. (Core forming process)

  Next, as shown in FIG. 9, the hoop is separated from the hoop and separated into pieces, flux is applied to the terminals 13 and solder dipping is performed to solder the terminals 13 of the portion projecting from the magnetic core 11 and the end 12a of the coil element. . By doing this, it is possible to create a state in which the terminal 13 and the coil element 12 are not joined at the portion embedded in the magnetic core 11 and are joined at the outside of the magnetic core 11.

  Next, as shown in FIG. 10, the terminal 13 is cut at a predetermined length, the terminal 13 is bent along the side surface of the magnetic core 11, and the terminal 13 is bent toward the bottom of the magnetic core 11 to obtain a coil component. be able to. (Terminal formation process)

  Here, FIG. 8, FIG. 9, and FIG. 10 are perspective views through the powder compact 19 or the magnetic core 11, and the outline of the powder compact 19 or the magnetic core 11 is indicated by a broken line. 6, 7, and 8 show the bottom side of the coil component in the upper side of the drawing and the upper side of the coil component in the lower side of the drawing in a vertically inverted perspective view. It is.

  The coil component according to the present invention is industrially useful because it can obtain a coil component that can both improve the vibration resistance and impact resistance of the coil component and cope with increasing the current.

DESCRIPTION OF SYMBOLS 11 Magnetic core 12 Coil element 12a End part of coil element 13 Terminal 14 Concave part 15 Convex part 16 Bottom part 17 Protrusion part 18 Step processed part 19 Green powder 20 Protrusion part 21 Flat part of terminal

Claims (7)

A magnetic material is mixed with a binder and made into powder, and a magnetic material is formed by pressure molding, a coil element embedded in the magnetic core and having the end protruded from the side surface of the magnetic core, and the end of the coil element connected And a terminal bent along the bottom surface from the side of the magnetic core,
The terminal is provided with a recessed portion recessed in a direction opposite to the side surface of the magnetic core on the side surface of the magnetic core and a stepped portion having a convex portion formed on the back surface thereof.
The end of the coil element is connected to the bottom of the recess,
The coil is characterized in that a linear protrusion which is embossed from the back side of the recess is provided at the bottom of the recess, and the protrusion and the end of the coil element are intersected and welded. parts. A magnetic material is mixed with a binder and made into powder, and a magnetic material is formed by pressure molding, a coil element embedded in the magnetic core and having the end protruded from the side surface of the magnetic core, and the end of the coil element connected And a terminal bent along the bottom surface from the side of the magnetic core,
The terminal is provided with a recessed portion recessed in a direction opposite to the side surface of the magnetic core on the side surface of the magnetic core and a stepped portion having a convex portion formed on the back surface thereof.
The end of the coil element is connected to the bottom of the recess,
The bottom portion of the recess is provided with a linear protrusion stamped from the back side of the recess, and the protrusion and the end of the coil element are intersected and welded.
The projecting height dimension of the said projection part is smaller than the depth dimension of the said recessed part, The coil components characterized by the above-mentioned. A coil portion forming step of spirally winding a conductive wire to form a coil element; a welding step of welding a terminal obtained by processing a metal plate and an end portion of the coil element;
A core forming step of forming a magnetic core by embedding one end of the coil element and the terminal in a mixture of a magnetic material and a binder and forming the core by pressure molding, and bending the terminal along the bottom surface from the side of the core And a terminal forming step of forming a terminal,
In the welding step, a recessed portion recessed in the direction opposite to the side surface of the magnetic core and a stepped portion formed with a protruding portion on the back surface are formed in the terminal by pressing, and the end of the coil element is formed on the bottom portion of the recessed portion. Weld the parts,
Forming the stepped portion up to the side lower edge of the magnetic core;
In the radius of curvature of the bent portion of the flat portion of the terminal and the stepped portion, the radius of curvature of the lower edge portion of the magnetic core is R1, and the radius of curvature of the bent portions of both ends of the coil element is R2. And R1> R2. A method of manufacturing a coil component. The coil portion forming step of forming a coil element by spirally winding a conducting wire, a welding step of welding a terminal obtained by processing a metal plate and an end portion of the coil element, a mixture of a magnetic material and a binder A core forming step of forming a magnetic core by embedding a coil element and one end of the terminal and pressing it, and a terminal forming step of forming a terminal by bending the terminal along the bottom surface from the side of the magnetic core ,
In the welding step, a recessed portion recessed in the direction opposite to the side surface of the magnetic core and a stepped portion formed with a protruding portion on the back surface are formed in the terminal by pressing, and the end of the coil element is formed on the bottom portion of the recessed portion. Weld the parts,
A method of manufacturing a coil component, comprising: forming a linear projection which is stamped from the back side of the recess on the bottom of the recess, and crossing the projection and the end of the coil element for welding. The coil portion forming step of forming a coil element by spirally winding a conducting wire, a welding step of welding a terminal obtained by processing a metal plate and an end portion of the coil element, a mixture of a magnetic material and a binder A core forming step of forming a magnetic core by embedding a coil element and one end of the terminal and pressing it, and a terminal forming step of forming a terminal by bending the terminal along the bottom surface from the side of the magnetic core ,
In the welding step, a recessed portion recessed in the direction opposite to the side surface of the magnetic core and a stepped portion formed with a protruding portion on the back surface are formed in the terminal by pressing, and the end of the coil element is formed on the bottom portion of the recessed portion. Weld the parts,
A linear protrusion which is embossed from the back side of the recess is provided on the bottom of the recess, and the protrusion and the end of the coil element are crossed and welded.
The projecting height dimension of the said projection part is smaller than the depth dimension of the said recessed part, The manufacturing method of the coil components characterized by the above-mentioned. A magnetic core having a side surface and a bottom surface, and a coil element having a main body embedded in the magnetic core and an end drawn from the side surface of the magnetic core, the magnetic core having a side surface and a bottom surface; A terminal connected to the end of the coil element and bent along the bottom surface from the side surface of the magnetic core;
In the portion of the terminal along the side surface of the magnetic core, a flat portion and a concave portion recessed from the flat portion in a direction opposite to the side surface of the magnetic core to accommodate a part of the end of the coil element And are provided,
The recess of the terminal includes a bottom and a protrusion projecting from the bottom, and the end of the coil element is connected to the protrusion of the recess of the terminal. parts. A magnetic core having a side surface and a bottom surface, and a coil element having a main body embedded in the magnetic core and an end drawn from the side surface of the magnetic core, the magnetic core having a side surface and a bottom surface; A terminal connected to the end of the coil element and bent along the bottom surface from the side surface of the magnetic core;
In the portion of the terminal along the side surface of the magnetic core, a flat portion and a concave portion recessed from the flat portion in a direction opposite to the side surface of the magnetic core to accommodate a part of the end of the coil element And are provided,
A radius of curvature R1 in a cross section perpendicular to a bottom surface of the magnetic core of a portion of the boundary between the flat portion and the recess of the terminal facing the tip of the end of the coil element is the flat of the terminal When a radius of curvature in a cross section parallel to the bottom surface of the magnetic core of a portion along a direction in which the end portion of the coil element extends in a boundary portion between the portion and the recess is R1> R
A coil part characterized by being 2.

Images