JP7247942B2 - Inductor and manufacturing method thereof - Google Patents

Description

The present invention relates to inductors and methods of manufacturing the same.

In Patent Document 1, a winding portion in which a conductive wire having a rectangular cross section and a coating layer is wound in two stages so as to be connected at the innermost circumference, and a winding portion from the outermost circumference of the winding portion. A coil having a drawn out part is made of a magnetic material containing magnetic powder and resin, the winding axis of the winding part is perpendicular to the mounting surface, and the flat surface of the terminal end of the drawn part is opposed to the mounting surface. An inductor has been proposed which has a rectangular parallelepiped body formed by embedding and pressurizing so as to be exposed to the end face of the body, and external electrodes formed over the opposing end face and the adjacent face of the body. there is

U.S. Patent Application Publication No. 2016/0126006

In an inductor, the element body is formed by embedding a coil in a composite material containing magnetic powder so that the lead-out part of the coil is exposed on the surface of the element body, and pressing it in a molding die. is inclined with respect to the bottom surface of the element when pressurized, and the positions of the coils in the element may vary. Variation in the L value of the inductor occurs due to the variation in the position of the wound portion of the coil in the element body. SUMMARY OF THE INVENTION It is an object of the present invention to provide an inductor and a method of manufacturing the same in which displacement of the winding portion is suppressed during molding of the element body.

A first aspect includes a coil having a winding portion formed by winding a conductor and a pair of lead portions drawn from the outermost circumference of the winding portion, and a magnetic portion containing the coil and containing magnetic powder, and a mounting surface. a base body having a side bottom surface, a top surface facing the bottom surface, and two end surfaces adjacent to the bottom surface and facing each other; and an inductor. The conductor has a substantially rectangular cross-sectional shape that is defined by its thickness and width in a direction perpendicular to its extending direction. The winding part is wound with the plane defined by the width of the conductor parallel to the winding axis, and is wound in two stages, upper and lower, connected at the innermost circumference, and the conductor is wound at both ends at the outermost circumference. will be located in In the coil, when viewed from the end face side, the upper end in the width direction at the leading end of the lead-out portion from the upper stage of the winding section is disposed closer to the bottom surface than the first opening surface on the upper stage side of the winding section. In addition, when viewed from the end face of the coil, the lower end in the width direction of the leading end of the lead-out portion from the lower stage of the winding section is arranged on the upper surface side of the second opening surface on the lower stage side of the winding section.

A second embodiment comprises a step of preparing a coil having a winding part in which a conductor is wound and a lead part drawn out from the outermost circumference of the winding part, and a composite material containing magnetic powder, a bottom part, and a bottom part A first preformed body having a winding shaft portion disposed in the coil winding portion and inserted into the space of the winding portion of the coil, and a wall portion disposed surrounding the periphery of the bottom portion, the wall portion having a cutout portion in a part of the wall portion inserting the winding shaft portion into the space of the winding portion, arranging the end portion of the drawer portion in the notch portion, surrounding the winding portion of the coil with the wall portion, and forming the first preform A step of arranging the coil inside, and pressure-molding the first preform having the coil arranged in the mold in the direction of the winding axis of the winding part to enclose the winding part of the coil and pull it out. A method of manufacturing an inductor, comprising the steps of: obtaining an element body in which at least a part of the end portion of the lead portion is exposed; and forming an external electrode connected to the end portion of the lead portion. The conductor has a substantially rectangular cross-sectional shape that is defined by its thickness and width in a direction perpendicular to its extending direction. In the wound part, the conductor is wound with both ends positioned at the outermost circumference, with the plane defined by the width parallel to the winding axis, and connected at the innermost circumference and wound in two stages, upper and lower. become. In the coil, when viewed from the end face side, the upper end in the width direction at the leading end of the lead-out portion from the upper stage of the winding section is disposed closer to the bottom surface than the first opening surface on the upper stage side of the winding section. In addition, when viewed from the end face side, the lower end in the width direction of the leading end of the lead-out portion from the lower stage of the winding section is arranged on the upper surface side of the second opening surface on the lower stage side of the winding section.

Advantageous Effects of Invention According to the present invention, it is possible to provide an inductor and a method of manufacturing the same in which displacement of the winding portion during molding of the element body is suppressed.

1 is a partially transparent perspective view of the inductor of Example 1 as seen from the upper surface side; FIG. 2 is a partially transparent plan view of the inductor of Example 1 as seen from the upper surface side; FIG. 3 is a partially transparent plan view of the element body in the inductor of Example 1, viewed from one end face side; FIG. 3 is a partially transparent plan view of the element body in the inductor of Example 1 as seen from the other end face side; FIG. FIG. 11 is a partially transparent plan view of the element body in the inductor of Example 2 as viewed from one end face side; FIG. 10 is a partially transparent plan view of the element body in the inductor of Example 2 as seen from the other end face side;

The inductor includes a winding portion formed by winding a conductor, a coil having a pair of lead portions drawn from the outermost periphery of the winding portion, and a magnetic portion containing the coil and containing magnetic powder. a base body having a bottom surface, a top surface opposite to the bottom surface, and two end surfaces adjacent to the bottom surface and facing each other; and a pair of external electrodes each having at least terminal ends of lead portions connected at the end surfaces of the base body. , provided. The conductor that forms the coil has a substantially rectangular cross-sectional shape that is defined by its thickness and width in a direction orthogonal to the extending direction. The winding part is wound with the plane defined by the width of the conductor parallel to the winding axis, and is connected at the innermost circumference and wound in two upper and lower stages, and the conductor is wound at both ends on the outermost circumference. It will be placed in the department. In the coil, when viewed from the end face side, the upper end in the width direction at the leading end of the lead-out portion from the upper stage of the winding portion is arranged closer to the bottom surface than the first opening surface on the upper stage side of the winding portion. In addition, when viewed from the end face side, the lower end in the width direction of the leading end of the lead-out portion from the lower stage of the winding section is arranged on the upper surface side of the second opening surface on the lower stage side of the winding section.

When viewed from the end face side, the upper end in the width direction at the leading end of the lead-out portion from the upper stage of the winding part is arranged closer to the bottom surface than the first opening surface on the upper stage side of the winding part. Sometimes, the lower end in the width direction of the leading end of the lead-out portion from the lower stage of the winding part is arranged on the upper surface side than the second opening surface on the lower stage side of the winding part, so that the Positional deviation is suppressed. At the time of pressure molding, the end of the drawn-out portion may be caught by the molding die, etc., or the wound portion may be caught by the winding shaft portion of the preform, causing the position of the wound portion to shift in the element body. be. On the other hand, by bending the end portion of the drawn-out portion of the coil in a predetermined direction in advance, the catching is suppressed, and as a result, the displacement of the wound portion is suppressed.

In the coil, the center in the width direction of the leading end of the lead-out portion from the upper stage of the winding portion may be arranged substantially in the center between the first opening surface and the second opening surface when viewed from the end face side. Further, the center in the width direction of the leading end of the lead-out portion from the lower stage of the winding portion may be arranged substantially in the center between the first opening surface and the second opening surface when viewed from the end face side. As a result, displacement of the winding portion is more effectively suppressed.

The coil may be arranged so that the upper end in the width direction on the side of the winding portion substantially coincides with the first opening surface when viewed from the end face side at the end portion of the upper lead-out portion of the winding portion. In addition, the lower end in the width direction of the winding portion may be disposed so as to substantially coincide with the second opening when viewed from the end surface side at the end portion of the drawer portion on the lower stage of the winding portion. As a result, displacement of the winding portion is more effectively suppressed.

In the coil, the upper end in the width direction on the side of the winding portion may be arranged closer to the bottom surface than the first opening surface when viewed from the end surface side at the end portion of the lead-out portion from the upper stage of the winding portion. again,
At the end portion of the lead-out portion from the lower stage of the winding portion, the widthwise lower end on the winding portion side may be arranged on the upper surface side of the second opening surface when viewed from the end face side. This reduces the load of bending the coil.

The coil may consist of 2.5 turns. If the number of turns of the winding part is small, the size of the winding part becomes small, so that it tends to fall down and positional deviation is likely to occur. , is effectively suppressed.

A method for manufacturing an inductor includes a coil preparation step of preparing a coil having a winding portion formed by winding a conductor and a lead portion drawn out from the outermost circumference of the winding portion, and a composite material containing magnetic powder. and a winding shaft portion arranged on the bottom portion and inserted into the space of the winding portion of the coil; a preform preparation step of preparing a preform; inserting the winding shaft into the space of the winding portion; , a coil arranging step of arranging the coil inside the first preform, and pressure-molding the first preform, in which the coil is arranged, in the winding axis direction of the winding portion in the molding die to form the coil a pressure molding step for obtaining a base body in which at least a part of the end portion of the lead portion is exposed to the surface; and an external electrode forming step for forming an external electrode connected to the end portion of the lead portion. ,including. The conductor that forms the coil has a substantially rectangular cross-sectional shape that is defined by its thickness and width in a direction orthogonal to the extending direction. In the wound part, the conductor is wound with both ends positioned at the outermost circumference, with the plane defined by the width parallel to the winding axis, and connected at the innermost circumference and wound in two stages, upper and lower. become. In the coil, when viewed from the end face side, the upper end in the width direction at the leading end of the lead-out portion from the upper stage of the winding section is disposed closer to the bottom surface than the first opening surface on the upper stage side of the winding section. In the coil, when viewed from the end face side, the lower end in the width direction at the leading end of the lead portion from the lower stage of the winding section is arranged on the upper surface side of the second opening surface on the lower stage side of the winding section.

By bending in advance the ends of the lead-out portions of the coil exposed from the element body in a predetermined direction, displacement of the winding portion during molding of the element body is suppressed.

The base body is obtained by disposing a composite material containing magnetic powder on a first preform on which a coil is arranged, and integrally press-molding the first preform and the composite material in a molding die. may be As a result, the step of preparing the second preformed body in advance can be omitted, and the man-hours of the manufacturing method as a whole can be reduced.

The base body is obtained by disposing a flat plate-shaped second preform on the first preform on which the coil is arranged, and integrally pressing the first preform and the second preform in the molding die. It may be obtained by compression molding. By using the second preformed body, the formed body is efficiently formed, and the production quality of the formed body is more stabilized.

The coil may consist of 2.5 turns. In general, when the number of windings of the winding part is small, the difference between the size of the winding part and the size of the drawer part becomes small, so it tends to fall down and the position of the drawer part tends to be misaligned. By doing so, positional displacement of the winding portion is effectively suppressed.

In this specification, the term "process" is not only an independent process, but even if it cannot be clearly distinguished from other processes, it is included in this term as long as the intended purpose of the process is achieved. . BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. However, the embodiments shown below are examples of inductors and manufacturing methods thereof for embodying the technical idea of the present invention, and the present invention is not limited to the inductors and manufacturing methods thereof shown below. It should be noted that the members shown in the claims are by no means limited to the members of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified. It's nothing more than Note that the sizes and positional relationships of members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same names and symbols denote the same or homogeneous members, and detailed description thereof will be omitted as appropriate. Furthermore, each of the elements constituting the present invention may be composed of a plurality of elements with the same member, and one member may be used as a plurality of elements, or conversely, the function of one member may be replaced by a plurality of members. It can also be realized by sharing with . In addition, the embodiments are shown separately for the sake of convenience in consideration of the explanation of the main points or the ease of understanding, but the configurations shown in different embodiments can be partially replaced or combined. In the second and subsequent embodiments, the description of matters common to the first embodiment will be omitted, and only the points of difference will be described. In particular, similar actions and effects due to similar configurations will not be mentioned sequentially for each embodiment.

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

Example 1
The inductor of Example 1 is demonstrated with reference to FIGS. 1-4. FIG. 1 is a partially transparent perspective view of the inductor 100 viewed from above. FIG. 2 is a partially transparent plan view of the inductor 100 viewed from the top side. FIG. 3 is a partially transparent plan view of the element forming the inductor 100 as viewed from one end face side. FIG. 4 is a partially transparent plan view of the element forming the inductor 100 as viewed from the other end face side.

As shown in FIGS. 1 and 2, an inductor 100 is arranged on a base body 10 including a coil 30, a magnetic portion containing magnetic powder and resin and containing the coil 30, and a surface of the base body 10. A pair of external electrodes 40 a and 40 b electrically connected to the coil 30 are provided. The base body 10 has a substantially rectangular parallelepiped shape, and includes a bottom surface 12 on the mounting surface side, a top surface 14 facing the bottom surface 12 in the height direction (T direction), and an upper surface 14 adjacent to the bottom surface 12 and substantially orthogonal to each other. It has two end faces 16a and 16b facing each other in the width direction (L direction) and two side faces 18a and 18b which are adjacent to the bottom face 12 and the end face 16 and substantially perpendicular to each other and face each other in the width direction (W direction). The coil 30 has a winding portion 32 formed by winding a conductor around a winding axis N and a pair of extension portions 36 a and 36 b extending from the outermost periphery of the winding portion 32 . The coil 30 is enclosed in the element body 10 with the terminal portion 34a of one lead-out portion 36a exposed to the end face 16a of the element body 10 and the terminal portion 34b of the other lead-out portion 36b exposed to the end face 16b of the element body 10. be. One external electrode 40a is arranged over five surfaces of the base body 10, ie, the bottom surface 12, the end surface 16a, the side surfaces 18a and 18b, and the top surface 14, and is connected to the end portion 34a of the lead portion 36a of the coil 30 exposed at the end surface 16a. be done. The other external electrode 40b is arranged over the five surfaces of the base body 10, that is, the bottom surface 12, the end surface 16b, the side surfaces 18a and 18b, and the top surface 14, and is connected to the end portion 34b of the lead portion 36b of the coil 30 exposed at the end surface 16b. do. The ridges of the body 10 are chamfered, and the faces of the body are connected by curved surfaces. In FIG. 1, a dashed line may be used as an auxiliary line for representing a curved surface.

The coil 30 has a coating layer on its surface, and is formed by winding a conductor wire having a substantially rectangular cross-sectional shape that is defined by the thickness and width of the conductor perpendicular to the extension direction (length direction) of the conductor. The wound portion 32 of the coil 30 has both ends of the conductor positioned at the outermost periphery, and one of the surfaces defined by the width of the conductor is on the outer peripheral side and the other surface is on the inner peripheral side. The surface defined by the width is parallel to the winding axis, and the conductor is spirally wound so that at least a part of the surface defined by the width overlaps, and the conductor is connected at the innermost peripheral part. are wound in two stages (so-called α-winding) with the surfaces defined by the thickness of . In inductor 100, coil 30 consists of 2 turns of winding and 1/4 turn of each lead, for a total of 2.5 turns. The coil 30 is included in the element body 10 with the winding axis N of the winding portion 32 substantially orthogonal to the bottom surface 12 and the top surface 14 of the element body 10 . A lead-out portion 36a extends from the outermost periphery of the winding portion 32 on the upper surface 14 side, with its tip portion directed toward one side surface 18a of the element body, and a surface defined by the width of the conductor at the end portion 34a. are exposed on the end surface 16a of the base body 10. As shown in FIG. A leading end portion 36b is led out toward one side surface 18a of the element body from the lower outermost peripheral portion of the winding portion 32 on the side of the bottom surface 12, and the end portion 34b is defined by the width of the conductor. are exposed on the end face 16b of the base body 10. As shown in FIG. The covering layer is removed from the surface of the conductor at the end portions 34a, 34b exposed from the end faces 16a, 16b, respectively, and electrically connected to the external electrodes 40a, 40b.

FIG. 3 is a partially transparent plan view of the inductor 100 viewed from one end surface 16a, and for the sake of explanation, the external electrodes are not shown. At the end face 16a, the end portion 34a of the lead-out portion 36a from the upper stage of the winding portion is exposed from the end face 16a. The winding portion has a first opening surface P1 on its upper side and a second opening surface P2 on its lower side. That is, the first opening surface P1 is a surface formed along the thickness direction surface of the conductor in the wound portion, and faces the upper surface 14 of the element. Further, the second opening surface P2 is a surface formed along the thickness direction surface of the conductor in the winding portion, and faces the bottom surface 12 of the element. The position in the height direction (T direction) of the upper end E1a in the width direction of the conductor at the leading end of the lead portion is located on the side of the bottom surface 12 by the length d1a from the position in the height direction of the first opening surface P1 of the winding portion. be. In addition, the position in the height direction (T direction) of the lower end E2a in the width direction at the leading end of the lead-out portion is located on the upper surface 14 side by a length d2a from the position in the height direction of the second opening surface P2 of the winding portion. be. It is preferable that the length d1a and the length d2a are substantially the same. That is, the widthwise center position of the conductor at the leading end of the lead-out portion is preferably located near the boundary surface between the upper stage and the lower stage, which is substantially the center between the first opening plane P1 and the second opening plane P2.

In FIG. 3, the lead-out portion 36a is bent toward the bottom surface 12 from the position of the first opening P1 immediately after being pulled out from the winding portion. Therefore, the upper end in the width direction of the winding portion side of the end portion 34a is arranged closer to the bottom surface than the first opening surface.

FIG. 4 is a partially transparent plan view of the inductor 100 viewed from the other end surface 16b side, and the external electrodes are not shown for the sake of explanation. At the end face 16b, the end portion 34b of the lead-out portion 36b from the lower stage of the winding portion is exposed from the end face 16b. The position in the height direction (T direction) of the lower end E2b in the width direction at the leading end of the lead-out portion is located on the upper surface 14 side by a length d2b from the height direction position of the second opening surface P2 of the winding portion. In addition, the position in the height direction (T direction) of the upper end E1b in the width direction at the leading end of the drawer portion is located on the side of the bottom surface 12 by the length d1b from the position in the height direction of the first opening surface P1 of the winding portion. be. It is preferable that the length d1b and the length d2b are substantially the same. That is, it is preferable that the widthwise central position of the leading end of the lead-out portion is located near the boundary surface between the upper and lower stages, which is approximately the center between the first opening plane P1 and the second opening plane P2.

In FIG. 4, the drawer portion 36b is bent toward the upper surface 14 from the position of the second opening surface P2 immediately after being drawn out from the winding portion. Therefore, the widthwise lower end of the end portion 34b on the winding portion side is arranged on the upper surface side of the second opening surface.

The size of the base body 10 is such that the length L is, for example, 1 mm or more and 3.4 mm or less, preferably 1 mm or more and 3 mm or less, and the width W is, for example, 0.5 mm or more and 2.7 mm or less, preferably 0.5 mm or more. It is 5 mm or less, and the height T is, for example, 0.5 mm or more and 2 mm or less, preferably 0.5 mm or more and 1.5 mm or less. Specifically, the size of the element is L×W×T, for example, 1 mm×0.5 mm×0.5 mm, 1.6 mm×0.8 mm×0.8 mm, 2 mm×1.2 mm×1 mm, 2 .5mm x 2mm x 1.2mm.

The magnetic portion constituting the element body 10 is made of a composite material containing magnetic powder and resin. Magnetic powders include Fe, Fe—Si, Fe—Ni, Fe—Si—Cr, Fe—Si—Al, Fe—Ni—Al, Fe—Ni—Mo, Fe—Cr—Al, and other iron-based powders. Metal magnetic powder, metal magnetic powder of other compositions, metal magnetic powder such as amorphous metal powder, metal magnetic powder whose surface is coated with an insulating layer such as glass, metal magnetic powder whose surface has been modified, nano-level fine metal Magnetic powder is used. Thermosetting resins such as epoxy resins, polyimide resins, and phenol resins, and thermoplastic resins such as polyethylene resins, polyamide resins, and liquid crystal polymers are used as resins. The filling rate of the magnetic powder in the magnetic portion is, for example, 50% by mass or more and 85% by mass or less, preferably 60% by mass or more and 85% by mass or less, or 70% by mass or more and 85% by mass or less. The filling factor can be obtained from the average value of the diameters of the magnetic powder in a predetermined central area of the cross section in the longitudinal direction passing through the center of the inductor.

The external electrodes 40a and 40b may be conductive layers containing conductive particles such as silver particles and copper particles and a binder resin. Furthermore, the external electrode may include a plating layer formed on the conductive layer. The plating layer may include, for example, a layer formed of nickel and a layer formed thereon and formed of tin. Also, the external electrodes 40a and 40b may be plated layers. The plated layers are, for example, a first layer formed of copper, a second layer formed on the first layer and formed of nickel, and a third layer formed on the second layer and formed of tin. may be provided. The region in which the external electrodes are formed may be a magnetic powder exposed region obtained by removing a part of the resin forming the element and a part of the insulating layer covering the surface of the magnetic powder from the surface of the element. In the magnetic powder exposed region, a part of the magnetic powder is linked to form a network structure, so that the plating layer can be easily formed, and the adhesion of the conductive layer to the element body is improved.

The thickness of the conductor may be, for example, 0.01 mm or more and 1 mm or less. The width of the conductor may be, for example, 0.1 mm or more and 2 mm or less. The aspect ratio (width/thickness) of the conductor cross-section may be, for example, 1/1 or more, or 1/1 or more and 30/1 or less. Moreover, the coating layer that covers the conductor is formed of an insulating resin such as polyimide or polyamideimide having a thickness of, for example, 2 μm or more and 20 μm or less. In order to prevent unwinding of the wound portion, a fusible layer containing a self-fusing component such as a thermoplastic resin or a thermosetting resin may be further provided on the surface of the coating layer, and the thickness thereof is 1 μm. It may be formed to have a thickness of 8 μm or more.

A protective layer may be arranged on the surface of the base body 10 . The protective layer may be arranged on the surface of the element other than the area where the external electrodes are arranged, or may be arranged on the surface of the element other than the area where the end portion of the lead portion is exposed. The protective layer may contain, for example, a resin. Thermosetting resins such as epoxy resins, polyimide resins, and phenol resins, and thermoplastic resins such as acrylic resins, polyethylene resins, and polyamide resins are used as resins constituting the protective layer. The protective layer may contain a filler. Non-conductive fillers such as silicon oxide and titanium oxide are used as fillers. The protective layer is formed, for example, by applying a resin composition containing a resin and a filler to the surface of the element by means of coating, dipping, or the like, and curing the applied resin as necessary. The protective layer may be formed from an inorganic material such as water glass. Also, the protective layer may be formed in a region other than the magnetic powder exposed region, which will be described later.

A marker (not shown) may be attached to the body 10 . A marker may be provided, for example, on the upper surface 14 of the element on the side where the lead-out portion 36b is led out from the lower stage of the winding portion 32 to indicate the polarity of the inductor. Markers are applied, for example, by printing, laser engraving, or the like.

Method for Manufacturing Inductor Next, a method for manufacturing an inductor will be described. The inductor can be manufactured by a manufacturing method including, for example, a coil preparation process, a preform preparation process, a coil arrangement process, a pressure molding process, and an external electrode formation process.

In the coil preparation step, a coil having a winding portion formed by winding a conductor and a lead-out portion drawn from the outermost circumference of the winding portion is prepared. The conductor that forms the coil may have a substantially rectangular cross-sectional shape that is defined by its thickness and width in a direction orthogonal to the extending direction. The winding portion of the coil is formed by winding the conductor in a spiral shape with the plane defined by the width of the conductor parallel to the winding axis. It is possible to obtain a coil which is formed by winding the coils in a wide range, and in which the lead portions are led out from the upper stage and the lower stage, respectively. When viewed from the direction orthogonal to the winding axis of the winding part, the coil is arranged so that the position of the upper end in the width direction at the tip of the lead part from the upper stage of the winding part is the position of the first opening surface on the upper side of the winding part. The position of the lower end in the width direction of the leading end of the lead-out portion from the lower stage of the winding part is arranged on the upper surface side than the position of the second opening surface on the lower stage side of the winding part. You can Also, the wound portion of the coil may be formed by further winding the conductor such that the planes defined by the width of the conductor overlap each other and the end portions do not overlap.

Since the lead-out portion of the coil prepared in the coil preparation process has a shape that is arranged at a predetermined position, positional deviation of the winding portion in the height direction of the element body during pressure molding of the element body is prevented. can be suppressed.

In the preform preparation step, a first preform is prepared by temporarily forming a composite material containing magnetic powder and resin. The first preform includes a bottom portion, a winding shaft portion disposed in the bottom portion and inserted into a space of the winding portion of the coil, and a wall portion disposed surrounding the bottom portion. It has a notch in the part. The bottom portion is formed in a plate shape and constitutes, for example, the bottom surface of the element. The winding shaft part is formed so as to be insertable into the space of the winding part of the coil, and is arranged such that its extending direction is substantially perpendicular to the bottom part. The wall portion is formed so as to accommodate the wound portion of the coil, and a notch portion is formed at a position corresponding to the end face of the element body to accommodate the end portion of the drawn-out portion of the coil. Moreover, the preform forming step may further include a step of preparing a flat plate-like second preform. The first preform and the second preform can be formed, for example, by filling a mold having a predetermined shape with a composite material and applying pressure.

In the coil arranging step, the winding shaft portion of the first preform is inserted into the prepared space of the winding portion of the coil, and the end portion of the lead-out portion of the coil is arranged in the cutout portion to form the first preform. Place the coil inside. As a result, the wound portion of the coil is surrounded by the wall portion of the first preform. Further, a composite material may be placed over the coil over the first preform, and a second preform over the coil may be placed over the first preform.

In the pressure molding step, the first preform having the coil disposed thereon is pressed in the molding die in the direction of the winding axis of the winding portion to form the element body. As a result, it is possible to obtain an element body that includes the wound portion of the coil and at least a portion of the end portion of the lead portion is exposed to the surface. In the pressure molding step, heat treatment may be performed as necessary.

In the external electrode forming step, external electrodes are formed that are electrically connected to the end portions of the lead portions exposed from the surface of the element body. The external electrode forming step may include, for example, forming a conductive layer by applying a conductive paste containing conductive particles such as silver particles or copper particles and a binder resin and curing the resin. Furthermore, the external electrode forming step may include plating the conductive layer to form a plated layer on the conductive layer. The plated layer formed may include, for example, a layer formed of nickel and a layer formed thereon of tin. In addition, in the external electrode forming step, the external electrodes may be formed on the surface of the element by, for example, plating. The external electrodes formed by plating are, for example, a first layer made of copper, a second layer made of nickel formed on the first layer, and a second layer made of nickel formed on the second layer and made of tin. and a third layer formed. The external electrode forming step may further include, prior to forming the external electrodes, forming magnetic powder exposed areas in the areas where the external electrodes are to be formed. The magnetic powder exposed region is, for example, a part of the resin constituting the element body, a part of the insulating layer covering the surface of the magnetic powder, etc. from the surface of the element body by irradiating the surface of the element body with laser light, sandblasting, etc. Removed and formed.

Example 2
The inductor of Example 2 will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is a partially transparent plan view of the element forming the inductor 110 as viewed from one end face side. FIG. 6 is a partially transparent plan view of the element forming the inductor 110 as viewed from the other end face side. The inductor 110 is a drawn-out portion drawn from the upper stage of the winding portion when viewed in a direction orthogonal to the winding axis, and the position of the upper end in the width direction of the winding portion side exposed from the element body is the first opening. The position of the lower end in the width direction of the winding part side exposed from the element body is the position of the second opening surface of the drawer part that is arranged substantially in line with the position of the surface and is pulled out from the lower stage of the winding part. is configured in the same manner as the inductor 100 except that it is arranged substantially in line with the .

FIG. 5 is a partially transparent plan view of the inductor 110 viewed from one end face 16a, and does not show the external electrodes for the sake of explanation. At the end face 16a, the end portion 34a of the lead-out portion 36a from the upper stage of the winding portion is exposed from the end face 16a. The winding portion has a first opening surface P1 on its upper side and a second opening surface P2 on its lower side. In FIG. 5, the position of the upper end in the width direction of the winding portion side of the end portion 34a is arranged to substantially match the position of the first opening surface P1. In addition, the position of the upper end in the width direction of the distal end side of the end portion 34a is arranged closer to the bottom surface 12 than the position of the first opening surface P1. That is, the end portion 34a is bent toward the bottom surface 12 at a position exposed from the end surface 16a.

FIG. 6 is a partially transparent plan view of the inductor 110 viewed from the other end face 16b side, and the external electrodes are not shown for the sake of explanation. At the end face 16b, the end portion 34b of the lead-out portion 36b from the lower stage of the winding portion is exposed from the end face 16b. In FIG. 6, the position of the widthwise lower end of the end portion 34b on the side of the winding portion is substantially aligned with the position of the second opening surface P2. In addition, the position of the lower end in the width direction on the tip side of the distal end portion 34b is arranged closer to the upper surface 14 than the position of the second opening surface P2. That is, the end portion 34b is bent toward the upper surface 14 at a position exposed from the end surface 16b.

In the inductor described above, the external electrodes are arranged over the bottom, side, top and end surfaces of the element, but they may be formed only on the bottom and end surfaces of the element. The end face of the conductor in the extending direction may be exposed on the side surface of the element body. The cross section perpendicular to the extending direction of the conductor is composed of a straight line, but may be composed of a curved line such as a semicircle or a semiellipse. The winding portion of the coil may be in a form such as edgewise winding other than the so-called α winding. The shape of the winding portion of the coil when viewed from the winding axis direction may be a shape other than an oval shape, such as a circular shape, an elliptical shape, or a chamfered polygonal shape. A concave portion (standoff) may be formed in a region where the external electrode is not arranged on the bottom surface of the element body. The concave portion provided on the base body bottom surface may have a semicircular shape in the height T direction when viewed from the width W direction.

10 element body 30 coil 40 external electrodes 100, 110 inductor

Claims (9)

A coil having a winding portion formed by winding a conductor and a pair of lead portions drawn from the outermost circumference of the winding portion;
an element containing the coil, including a magnetic portion containing magnetic powder, and having a bottom surface on the mounting surface side, an upper surface facing the bottom surface, and two end surfaces adjacent to the bottom surface and facing each other;
a pair of external electrodes to which at least the end portions of the lead portions are connected at the end faces of the element body;
The conductor has a substantially rectangular cross-sectional shape perpendicular to the extending direction defined by the thickness and width,
The winding part is wound with the plane defined by the width of the conductor parallel to the winding axis, and is connected at the innermost peripheral part and wound in two stages, upper and lower, so that the conductor is wound at both ends. is positioned at the outermost periphery,
When viewed from the end face side, the upper end in the width direction at the tip of the lead-out portion from the upper stage of the winding part is arranged on the bottom side than the first opening surface on the upper stage side of the winding part,
An inductor in which a lower end in a width direction of a leading end of a lead-out portion from a lower stage of the winding portion is arranged on an upper surface side than a second opening surface on the lower stage side of the winding portion when viewed from the end face side. The coil is
The center in the width direction of the leading end of the lead-out portion from the upper stage of the winding portion is arranged substantially in the center between the first opening surface and the second opening surface when viewed from the end face side,
2. The apparatus according to claim 1, wherein the center in the width direction of the leading end of the portion extending from the lower stage of the winding portion is arranged substantially in the center between the first opening surface and the second opening surface when viewed from the end face side. inductor. The coil is
At the terminal end of the lead-out portion from the upper stage of the winding portion, the upper end in the width direction of the winding portion side is arranged to substantially match the first opening surface when viewed from the end surface side,
2. A lower end in the width direction of the winding portion at an end portion of the lead-out portion extending from the lower stage of the winding portion is disposed so as to substantially match the second opening when viewed from the end face side. Inductors described in . The coil is
At the terminal end of the lead-out portion from the upper stage of the winding portion, the upper end in the width direction of the winding portion side is arranged closer to the bottom surface than the first opening surface when viewed from the end surface side,
2. A lower end in the width direction of the winding portion at an end portion of the lead-out portion extending from the lower stage of the winding portion is arranged on the upper surface side of the second opening when viewed from the end surface side. Inductors described in . The inductor according to any one of claims 1 to 4, wherein the coil has 2.5 turns. Preparing a coil having a winding portion formed by winding a conductor and a lead portion drawn out from the outermost circumference of the winding portion;
It is made of a composite material containing magnetic powder, and has a bottom, a winding shaft disposed in the bottom and inserted into the space of the winding portion of the coil, and a wall disposed surrounding the bottom. preparing a first preform having a notch in a portion of the wall;
The first preformed body is formed by inserting the winding shaft portion into the space of the winding portion, arranging the end portion of the drawer portion in the notch portion, and surrounding the winding portion of the coil with the wall portion. placing the coil inside a
In a molding die, the first preform having the coil disposed thereon is pressure-molded in the direction of the winding axis of the winding portion of the coil so as to enclose the winding portion of the coil and the end of the drawer portion. obtaining a body in which at least part of the portion is exposed on the surface;
forming an external electrode that connects with the distal end of the lead;
The conductor has a substantially rectangular cross-sectional shape perpendicular to the extending direction defined by the thickness and width,
In the winding part, the conductor is wound with both ends positioned at the outermost circumference and the plane defined by the width parallel to the winding axis, and is connected at the innermost circumference to form two stages, upper and lower. be wound,
The coil is
When viewed from the end face side, the upper end in the width direction at the tip of the lead-out portion from the upper stage of the winding part is arranged on the bottom side than the first opening surface on the upper stage side of the winding part,
A method of manufacturing an inductor, wherein a widthwise lower end of a leading end of a lead-out portion extending from a lower stage of the winding portion is arranged on an upper surface side of a second opening surface of the lower stage of the winding portion when viewed from the end face side. . The element is formed by disposing a composite material containing magnetic powder on a first preform on which the coil is arranged, and integrally pressure-molding the first preform and the composite material in a mold. 7. The manufacturing method according to claim 6, obtained by The base body is formed by disposing a flat plate-shaped second preform on a first preform on which the coil is arranged, and placing the first preform and the second preform in a mold. 7. The manufacturing method according to claim 6, which is obtained by integrally pressing and molding. The manufacturing method according to any one of claims 6 to 8, wherein the coil has 2.5 turns.

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