JP2024065863A - Coil, electronic component, winding jig, and method for manufacturing electronic component - Google Patents

Abstract

To provide a coil with high characteristics.SOLUTION: A coil has a winding part 11 formed by winding a wire 15. An inner peripheral shape of a cross section perpendicular to a winding axis of the winding part 11 has an outer peripheral shape comprising at least three first arcs A11-A14 and a plurality of connection lines A21, A22, A31, A32 connecting the adjacent first arcs to each other. The at least three first arcs A11-A14 are each an arc having a predetermined radius and a predetermined central angle at which the wire 15 can be bent.SELECTED DRAWING: Figure 2A

Description

The present disclosure relates to, for example, a coil wound with wire, an electronic component having a coil, a winding jig for manufacturing the coil, and a method for manufacturing the electronic component.

For example, in Patent Document 1, after a wire is wound around a bobbin to form a coil, the coil together with the bobbin is compressed in the axial direction, thereby curving the side of the bobbin around which the wire is wound outward, aligning the wire along the side of the bobbin, and stabilizing the shape.

JP 2010-287822 A

The structure of Patent Document 1 is difficult to apply to so-called air-core coils that do not have a core or bobbin, making it difficult to obtain air-core coils with high performance. This disclosure provides coils and electronic components with high performance, as well as a winding jig capable of manufacturing such coils and electronic components, and a method for manufacturing electronic components.

A coil according to an embodiment of the present disclosure includes:
A coil having a winding portion formed by winding a wire,
an inner peripheral shape of a cross section perpendicular to a winding axis of the winding portion has a shape including at least three first arcs and a plurality of connection lines connecting adjacent first arcs;
Each of the at least three first arcs has a predetermined radius and a predetermined central angle around which the wire can be bent.

In a coil of this configuration, the inner peripheral shape of the cross section perpendicular to the winding axis of the winding section has an inner peripheral shape consisting of at least three first arcs having a predetermined radius and a predetermined central angle around which the wire can be bent, and a plurality of connecting lines connecting adjacent first arcs. When winding the wire, no gap occurs between the winding section and the wire winding tool, or even if a gap occurs, it can be made small, resulting in a winding section with a stable shape with little variation in the wire. As a result, the variation in characteristics is reduced. Also, a coil with an improved Q value can be obtained. In particular, even when the size of the coil is small, a high-quality coil with stable shape and characteristics can be obtained.

In the coil, each of the multiple connection lines may be composed of one or more straight lines, one or more curved lines, or a combination of one or more straight lines and one or more curved lines. The curved lines may have a radius of curvature larger than the radius of any of the first arcs adjacent to the curved lines.

In any of the coils described above, at least three of the first arcs may be tangent-connected to the connection line.

In any one of the coils described above, the plurality of connecting wires are
a pair of second arcs opposed along one of two orthogonal axes;
a pair of third arcs opposed along the other of the two orthogonal axes;
The first arc may be disposed between the second arc and the third arc, a direction connecting the midpoint of the arc to a center point may form an angle of 45° with each of the two orthogonal axes, and the first arc may be connected tangently to each of the second arc and the third arc.

In any of the coils described above, the inner circumference shape of the cross section perpendicular to the winding axis of the winding portion may be a shape that has a solution such that both of the following two equations are positive.

Furthermore, an electronic component according to an embodiment of the present disclosure has any of the coils described above.

Moreover, a winding jig according to an embodiment of the present disclosure includes:
A winding jig for winding a wire, the cross section of which is as follows:
The peripheral shape is made up of at least three first arcs and a plurality of connection lines connecting adjacent first arcs,
Each of the at least three first arcs has a predetermined radius and a predetermined central angle within which the wire can be in close contact.

In the above winding jig, each of the multiple connection lines is composed of one or more straight lines, one or more curved lines, or a combination of one or more straight lines and one or more curved lines, and the curved lines may have a radius of curvature larger than the radius of any of the first circular arcs adjacent to the curved lines.

In any of the above winding jigs, at least three of the first arcs may be tangent-connected to the connection line.

In any of the above winding jigs, the cross section of the winding jig may be substantially rectangular with the four first arcs arranged at the four corners.

In any of the above winding jigs, at least one of the connection lines connecting the first arcs may be a combination of a plurality of the straight lines or may have a shape in which one or more of the curves protrude outward.

Moreover, a winding jig according to an embodiment of the present disclosure includes:
A winding jig for winding a wire, the cross section of which is as follows:
a pair of second arcs opposed along one of two orthogonal axes;
a pair of third arcs opposed to each other along the other of the two orthogonal axes;
four first arcs each disposed between the second arc and the third arc, each having a direction connecting a midpoint of the arc to a center point that forms an angle of 45° with each of the two orthogonal axes, and each connected tangently to the second arc and the third arc;
The shape has an outer periphery consisting of:

In the above winding jig, the cross section of the winding jig may have a shape that satisfies the two equations below, both of which are positive.

In addition, a method for manufacturing an electronic component according to an embodiment of the present disclosure includes a step of winding a wire around any one of the winding jigs described above.

FIG. 1A is a perspective view showing an overall configuration of a coil component according to an embodiment of the present disclosure. FIG. FIG. 1B is a perspective view showing the configuration of the coil portion 10 of the coil component shown in FIG. 1A. FIG. 1C is a diagram showing a state in which a wire is wound around a winding jig of a winding table of an automatic winding machine. FIG. 2A is a diagram showing a state in which a wire is wound around the winding jig shown in FIG. 1C, and is a cross-sectional view taken along line II-II in FIG. 1C. FIG. 2B is a diagram showing a coil portion formed by the process according to FIG. 2A. FIG. 2C is a cross-sectional view showing a state in which a wire is wound around a winding jig according to a first modified example of the present disclosure. FIG. 2D is a diagram showing a coil portion formed by the process according to FIG. 2C. FIG. 2E is a cross-sectional view showing a state in which a wire is wound around a winding jig according to a second modified example of the present disclosure. FIG. 2F is a diagram showing a coil portion formed by the process according to FIG. 2E. FIG. 3 is a diagram for explaining a cross-sectional shape of a winding jig according to an embodiment of the present disclosure. FIG. 4A is a first diagram for explaining wire characteristics required for determining the cross-sectional shape of a winding jig according to an embodiment of the present disclosure. FIG. 4B is a second diagram for explaining wire characteristics required for determining the cross-sectional shape of a winding jig according to an embodiment of the present disclosure. FIG. 5A is a diagram showing a comparative example of the present disclosure, illustrating a state in which a wire is wound around a winding jig having a rectangular cross section. FIG. 5B is a diagram illustrating the first embodiment of the present disclosure, showing a state in which a wire is wound around a winding jig having a substantially rectangular cross section with arc-shaped corners. FIG. 5C is a diagram showing a second embodiment of the present disclosure, illustrating a state in which a wire is wound around a winding jig having a substantially rectangular cross section with corners formed into arcs with a large radius of curvature. FIG. 6 is a diagram showing the Q characteristics of a coil component having each of the coil portions shown in FIGS. 5A to 5C.

Embodiments of the present disclosure will be described below with reference to the drawings. The embodiments of the present disclosure described below are examples for the purpose of explaining the present disclosure. Various components relating to the embodiments of the present disclosure, such as numerical values, shapes, materials, and manufacturing processes, can be modified or changed within the scope that does not cause technical problems.

In addition, the shapes and other details shown in the drawings of this disclosure do not necessarily match the actual shapes and other details, as the shapes and other details may have been altered for the purpose of explanation.

The coil component 1 according to one embodiment of the present disclosure shown in FIG. 1A is an electronic component in which an air-core coil (coil portion) 10 as an electronic element is sealed and housed inside an element body 40, that is, an electronic component in which an air-core coil is embedded in the element body 40. The coil component 1 is an inductor device used, for example, as a choke coil, a noise filter, etc., and is an electronic component that is particularly well suited for use in high-frequency applications.

The coil component 1 of this embodiment is a small electronic component whose maximum side length in the planar direction is, for example, 5 mm or less, or 3 mm or less, or 0.5 mm or less, and whose height is, for example, 5 mm or less, or 3 mm or less, or 0.5 mm or less.

The element body 40 is an exterior member that seals and houses the coil portion 10 inside. The element body 40 has a rectangular parallelepiped shape (hexahedron) as shown in FIG. 1A. The rectangular parallelepiped shape includes a rectangular parallelepiped with chamfered corners and edges, and a rectangular parallelepiped with rounded corners and edges.

In this embodiment, the base body 40 may be made of a resin containing magnetic powder, but is preferably made of a resin not containing magnetic powder. With such a configuration, the coil component 1 can be made into a coil component suitable for high frequency applications. The material of the base body 40 includes, for example, at least one of a thermosetting resin and a thermoplastic resin. The material of the base body 40 includes, as a thermosetting resin, at least one selected from the group consisting of, for example, an epoxy resin, a polyimide resin, a phenolic resin, and an unsaturated polyester resin. The polyimide resin is, for example, a bismaleimide resin. The material of the base body 40 includes, as a thermoplastic resin, at least one selected from the group consisting of, for example, a crystalline polystyrene, a fluororesin, a polyethylene, a liquid crystal polymer, and a polyphenylene sulfide (PPS). The fluororesin is, for example, a polytetrafluoroethylene (PTFE) resin. The base body may also be made of a filler-containing resin, in which the above resin includes a filler such as hollow glass or needle-shaped glass.

The bottom surface of the element body 40 is formed as a mounting surface 48 that faces a component installation surface (mounting surface of a board or the like) of a board or the like on which the coil component 1 is mounted. One surface (outer surface) of each of the first electrode 31 and the second electrode 32 is exposed on the mounting surface 48. The first electrode 31 and the second electrode 32 are arranged spaced apart in the X-axis direction on the mounting surface 48.

The shape and arrangement of the electrodes 31, 32 are not limited to those shown in FIG. 1A. For example, the exposed surfaces of the electrodes 31, 32 may be arranged on different surfaces, such as the top and bottom surfaces of the element body 40, opposing side surfaces, or any adjacent outer surface (including the top, bottom, and side surfaces). In addition, the L-shaped terminal electrode may be arranged at a corner of the element body 40 so as to straddle the mounting surface 48 and the side surface of the element body 40 adjacent thereto.

In this embodiment, the coil component 1 will be described with the Y-axis direction as the direction perpendicular to the mounting surface 48 of the coil component 1, the X-axis direction as the direction in which the first electrode 31 and the second electrode 32 of the two pairs of opposing edges that form the periphery of the mounting surface 48 are arranged, and the Z-axis direction as the direction perpendicular to the X-axis and Y-axis directions.

The coil section 10 is constructed by winding a conductor wire 15 into a coil shape, and in this embodiment, it is housed in the element body 40 in a position (vertical) in which the winding axis is parallel to the mounting surface. As shown in FIG. 1B, the coil section 10 has a winding section 11 around which the wire 15 is wound, and a first lead 12 and a second lead 13 which are both ends of the wire 15 drawn out from the winding section 11.

The cross-sectional shape of the winding section 11 in a plane perpendicular to the winding axis, in other words, the shape of the inner circumferential surface 17 of the winding section 11 (inner circumferential shape), and further in other words, the shape of the inner space 19 of the winding section 11 (outer circumferential shape), are predetermined shapes such that no gap occurs between the winding jig and the wire 15 when winding the wire 15, or even if a gap occurs, it is a small gap. In other words, the cross-sectional shape of the winding section 11 in a plane perpendicular to the winding axis is a specific shape obtained as a result of winding the wire 15 around a winding jig of such a predetermined cross-sectional shape.

The winding section 11 of the coil component 1 of the present disclosure is formed by winding the wire 15 around a winding jig such as an automatic winding machine. In the present disclosure, a parameter indicating the ease with which the wire bends when wound around the winding jig is measured in advance, and based on this parameter, the cross-sectional shape of the winding jig is determined to be a specific shape so that the wire 15 can be wound with almost no gap between the winding jig (in a tight contact state). Therefore, the shape of the winding section inner space 19 (FIG. 1B) of the winding section 11 in a plane perpendicular to the winding axis is a shape that is defined by the specific cross-sectional shape of the winding jig designed and determined in this way. However, the actual cross-sectional shape of the winding section 11 does not have to completely match the cross-sectional shape of the winding jig described above.

The specific cross-sectional shape of the winding jig is a shape that has an inner circumferential shape consisting of at least three first arcs with a predetermined radius and a predetermined central angle, in which the wire 15 can be bent by plastic deformation (not elastic deformation and without breaking), and multiple connection lines that connect adjacent first arcs. This "cross-sectional shape" of the winding jig will be described in detail later.

As shown in FIG. 1B, no material is disposed on the inner circumference 19 of the winding portion 11, but when the coil portion 10 is configured as the coil component 1, the material that constitutes the element body 40 is filled in as described above with reference to FIG. 1A.

As shown in FIG. 1A, the first lead 12 and the second lead 13 of the coil section 10 are pulled out from the side of the winding section 11 toward the mounting surface 48, and the ends 12e and 13e are connected to the first electrode 31 and the second electrode 32, respectively. As described below, the coil section 10 according to the present disclosure has corners formed as arcs with large curvature in a cross section perpendicular to the winding axis. By pulling out the first lead 12 and the second lead 13 from the side of the coil section 10, which is such an arc portion, the length of the first lead 12 and the second lead 13 is increased, the stray capacitance can be reduced, and the Q value is improved.

The wire 15 is mainly composed of a conductor portion containing a low-resistance metal such as copper, and an insulating coating that covers the outer circumference of the conductor portion. More specifically, the conductor portion is composed of pure copper such as oxygen-free copper or tough pitch copper, an alloy containing copper such as phosphor bronze, brass, red brass, beryllium copper, or a silver-copper alloy, or a copper-coated steel wire.

The insulating coating is not particularly limited as long as it has electrical insulation properties. Examples include epoxy resin, acrylic resin, polyurethane, polyimide, polyamideimide, polyesterimide, nylon, polyester, polyvinyl formal, etc., or a synthetic resin that is a mixture of at least two of the above resins.

In addition, in this embodiment, the wire 15 constituting the coil portion 10 is a round wire, and the cross-sectional shape of the conductor portion is circular, but it is not limited to a round wire, and may be a wire with a rectangular cross-section, a rectangular wire, etc. The wire diameter of the conductor portion of the wire 15 is not particularly limited, but for example, in the case of a round wire, it is 5 μm to 2 mm, or 10 μm to 1 mm. In the case of a rectangular wire, it is, for example, 10 μm to 2.5 mm thick and 100 μm to 1 mm wide.

In addition, the coil portion 10 of the coil component 1 of this embodiment is a coil in which the wire 15 is wound in a typical normal-wise manner, but the wire winding method is not limited to this. For example, the wire 15 may be an α-wound coil, or a flat-wound or edge-wound coil. The number of winding layers of the wire 15 is also not particularly limited. In this embodiment, the winding portion 11 is formed by winding one wire 15, but the winding portion 11 may be formed by winding two or more wires 15.

The first electrode 31 and the second electrode 32 are thin plate-shaped metal members that are installed on the mounting surface 48 of the element body 40 as shown in FIG. 1A, and electrically connect the coil section 10 to external wiring on the mounting board. The first electrode 31 is disposed on one side of the mounting surface 48 in the X direction, and the second electrode 32 is disposed on the other side of the mounting surface 48 in the X direction. The first electrode 31 and the second electrode 32 are embedded in the bottom surface of the element body 40 so that their lower surfaces are flush with the bottom surface of the element body 40.

As described above, the first electrode 31 is connected to the first lead 12 of the wire 15 constituting the coil section 10, and the second electrode 32 is connected to the second lead 13 of the wire 15 constituting the coil section 102. The connection between the first electrode 31 and the first lead 12 and the connection between the second electrode 32 and the second lead 13 are performed, for example, by laser welding the first lead end 12e and the second lead end 13e to the surface (connection wire portions 38, 38) opposite to the surface exposed to the mounting surface 48 of the first electrode 31 and the second electrode 32. The connection between the first electrode 31 and the first lead 12 and the connection between the second electrode 32 and the second lead 13 may be performed by other methods.

The first electrode 31 and the second electrode 32 are made of conductive metal plates such as tough pitch steel, phosphor bronze, brass, iron, nickel, etc. The first electrode 31 and the second electrode 32 may be formed as part of the wire 15 by crushing the end of the wire 15, i.e., as an integral structure with the wire 15.

Next, a method for manufacturing the coil component 1 will be described.
First, a winding jig 21 around which the wire 15 is wound to form the winding portion 11 of the coil component 1 of the present disclosure will be described.

As shown in FIG. 1C, the winding section 11 is formed by winding the wire 15 around the winding jig 21 of an automatic winding machine or other device. The winding jig 21 is provided, for example, in the winding table section 20 of the automatic winding machine, standing on a base 26 as shown in the figure. The winding section 11 is formed around the winding jig 21 by winding the wire 15 provided from a nozzle of the automatic winding machine (not shown) in a predetermined direction with a predetermined load force applied along the outer periphery of the winding jig 21. Note that the winding jig 21 is not limited to a form in which it is erected vertically upward on the base 26 as shown in FIG. 1C. For example, a configuration in which multiple winding jigs are installed so as to protrude horizontally from a wall surface formed perpendicular (vertically) to the base may be used.

The cross section of the winding jig 21 perpendicular to the winding axis is formed into a predetermined cross-sectional shape as shown by the shaded area in FIG. 2A. The cross-sectional shape of the winding jig 21 is designed and specified based on the size of the coil component 1 (cross-sectional size of the winding jig 21), the conditions for winding the wire 15, and parameters indicating the ease of bending of the wire 15 under those conditions, and is, for example, the shape shown in FIG. 2A.

2A has an outer circumferential shape in which four first circular arcs A ₁₁ to A ₁₄ , two second circular arcs A ₂₁ and A ₂₂ , and two third circular arcs A ₃₁ and A ₃₂ are smoothly connected in sequence. More specifically, the outer circumferential shape in the cross section of the winding jig 21 has two second circular arcs A ₂₁ and A ₂₂ arranged opposite each other along the Y axis, and two third circular arcs A ₃₁ and A ₃₂ arranged opposite each other along the X axis, and the four first circular arcs A ₁₁ to A ₁₄ are arranged to connect these.

The first arcs _A11 to _A14 are arcs having a predetermined radius and a predetermined central angle with the central positions _C11 to _C14 as their arc centers, respectively. The second arcs _A21 and _A22 are arcs having a predetermined radius and a predetermined central angle with the central positions _C21 and _C22 as their arc centers, respectively. The third arcs _A31 and _A32 are arcs having a predetermined radius and a predetermined central angle with the central positions _C31 and _C32 as their arc centers, respectively.

The centers _C21 , _C22 of the second arcs _A21 , _A22 are located on the Y-axis, the centers _C31 , _C32 of the third arcs _A31 , _A32 are located on the X-axis, and the straight lines connecting the midpoints of the first arcs _A11 to _A14 and the centers _C11 to _C14 are located on straight lines that form 45° with the X-axis and Y-axis, respectively. Also, the first to third arcs _A11 to _A14 , _A21 , _A22 , _A31 , _A32 all have their chords facing the origin, and the outer circumferential shape of the cross section of the winding jig 21 forms a convex figure.

These eight first to third circular arcs _A11 to _A14 , _A21 , _A22 , _A31 , and _A32 are smoothly connected in sequence at connection points P1 to P8, and in this embodiment, these eight circular arcs are tangent-connected at connection points P1 to P8, respectively. Tangent refers to a state in which the tangents at the connection point of adjacent arcs are equal, and when two arcs are tangent-connected, the centers of the two arcs and the connection points are arranged in a straight line.

2A, for example, in regard to the connection between the first arc _A11 and the second arc _A21 , the three points of the center _C11 of the first arc _A11 , the center _C21 of the second arc _A21 , and the connection point P1 between the first arc _A11 and the second arc _A21 are aligned on a straight line as shown in the figure. Also, a straight line perpendicular to this line at the connection point P1 is a tangent line at the connection point P1 between the first arc _A11 and the second arc _A21 , and they are coincident.

For example, in the connection between the first arc _A11 and the third arc _A31 , the center _C11 of the first arc _A11 , the center _C31 of the third arc _A31 , and the connection point P2 between the first arc _A11 and the third arc _A31 are aligned in a straight line as shown in the figure. Also, the straight line that intersects this straight line at a right angle at the connection point P2 is a tangent line at the connection point P1 between the first arc _A11 and the third arc _A31 , and they are coincident. In this way, adjacent arcs are connected in sequence tangent.

The method of determining the center positions, radii and central angles of the first to third circular arcs A ₁₁ to A ₁₄ , A ₂₁ , A ₂₂ , A ₃₁ and A ₃₂ will be described with reference to FIGS.

When determining the center position of each arc, etc., the length 2L1 of winding jig 21 in the X-axis direction (i.e., _L1 is 1/2 the length of winding jig 21 in the X-axis direction) and the length 2L2 of winding jig 21 in the Y-axis direction (i.e., _L2 is 1/2 the length of winding jig 21 in the Y-axis direction) are determined as conditions related to the size of the cross-sectional shape of winding jig 21 (which depends on the shape of coil component 1), as shown in Fig. _3. In addition, the wire ₁₅ to be wound around winding jig 21 and the load F to be applied in the bending direction when winding the selected wire 15 are selected.

Next, using the wire 15 to be actually wound and the load F during winding, a parameter indicating the ease with which the wire 15 bends when wound is measured as follows:

First, as shown in FIG. 4A, the wire 15 is placed on a horizontal work table 81, and one side of the wire 15 is pressed down by a pressing and holding member 82 up to a predetermined reference position X0, and one side of the wire 15 is fixed on the horizontal work table 81. In this state, the load F used when winding the wire is applied to the other side of the wire 15 (the free end side not pressed down by the pressing and holding member 82) in the bending direction, and the wire 15 is bent as shown.

As a result, the wire 15 is plastically deformed with approximately the maximum curvature within the range in which it will not break, and this state is analyzed to obtain a parameter indicating how easily the wire 15 bends. Specifically, as shown in FIG. 4(B), for a position Pw of the bent wire 15, the angle (normal angle) Φ between a straight line (normal) H perpendicular to the tangent to the wire 15 at that position Pw and a vertical axis Ys relative to the top surface of the horizontal work table 81 is detected. In addition, the value |ds/dΦ| obtained by differentiating the length s with the normal angle Φ at position Pw is detected as the radius of curvature r.

In this analysis, the bent state of the wire 15 up to the position Pw is approximated by a circle, and the bent state is represented by a radius of curvature r and a normal angle Φ. The radius of curvature r can be detected for all bent positions of the wire 15, i.e., for all normal angles Φ from 0° to 90°. Therefore, by selecting the minimum radius of curvature r _min from the combinations of the detected normal angles Φ and radii of curvature r, the radius of curvature (r _min ) of the part where the wire 15 to be wound is bent most by the load F during winding can be detected. Note that, as the bent state detection position Pw for determining the cross-sectional shape of the winding jig 21, it is preferable to select the position where the cross-sectional area of the winding jig 21, which is determined as described later based on the detection results, is the largest. Alternatively, the position where the wire 15 is bent most may be selected.

When the outer peripheral shape of the cross section of winding jig 21 around which wire 15 is wound does not include any bent portions (arc portions) with a radius of curvature smaller than this minimum radius of curvature r _min , and is smoothly formed by a combination of arc portions with a radius of curvature r (r≧r _min ), it is possible to wind wire 15 closely along the outer periphery of winding jig 21. As a result, the occurrence of a gap between wire 15 and the outer peripheral surface of winding jig 21 is prevented, or the gap can be made small.

Based on the parameters Φ and r (r _min ) indicating the bending ease of wire 15 detected in this manner and the sizes L ₁ and L ₂ of winding jig 21 described above, the cross-sectional shape of winding jig 21, i.e., the central positions, radii and central angles of the first to third circular arcs A ₁₁ to A ₁₄ , A ₂₁ , A ₂₂ , A ₃₁ , and A ₃₂ , are determined.

2A can be obtained by applying arcs with a radius of curvature r (r≧r _min ) and a central angle Φ to the first arcs A ₁₁ to A ₁₄ arranged at the four corners, and then arranging second arcs A ₂₁ , A ₂₂ and third arcs A ₃₁ , A ₃₂ , which have larger radii of curvature than these, by sequentially connecting them tangentically within a range of 2L ₁ ×2L ₂ , the size of the winding jig 21. Note that there is not limited to one shape that satisfies the above conditions, but if there are multiple cross-sectional shapes that satisfy the conditions, it is preferable to select the shape with the largest area among them.

The cross-sectional shape of the winding jig 21 can also be specified according to the conditions shown in Fig. 3. Like the shape shown in Fig. 2A, the shape shown in Fig. 3 has first to third circular arcs _A11 to _A14 , _A21 , _A22 , _A21 , and _A22 smoothly connected in sequence at connection points P1 to P8. In the shape shown in Fig. 3 as well, the first circular arcs _A11 to _A14 arranged at the four corners are arranged as arcs with a radius of curvature R (R = r ≥ _rmin ) and a central angle Φ based on the parameters Φ and r ( _rmin ) measured by the method shown in Fig. 4.

In addition, in the shape (conditions) shown in FIG. 3, the central angle θ of the _second circular arcs _A and _A is the same as the central angle θ of the third circular arcs A _{and A.} Under such conditions, the following relational expression holds based on geometric characteristics.

Then, by solving these as simultaneous equations, the center coordinates (X, Y) of the first arc A ₁₁ are given by the following values.

In other words, the cross section of the winding jig 21 according to the present disclosure has a shape that satisfies both of the above X and Y, i.e., the two equations below, for which both are positive.

Based on this, the radius R ₂ of the second arc A ₂₁ , the radius R ₃ of the third arc A ₃₁ , the center coordinates (0, Y ₂ ) of the second arc A ₂₁ , and the center coordinates (X ₃ , 0) of the third arc A ₃₁ are determined as follows.

The cross section of the winding jig 21 according to the present disclosure is formed into the shape shown here.

In manufacturing the coil component 1, first, the coil section 10 is manufactured. As shown in FIG. 1C, for example, an automatic winding machine applies a predetermined tension to the wire 15, and the wire 15 is wound around the outer circumference of the winding jig 21 formed in the above-mentioned shape, thereby manufacturing the coil section 10.

At this time, tension is applied to the wire 15 so that a predetermined load F acts in the bending direction. As described above, the winding jig 21 according to the present disclosure has a cross-sectional shape formed so that the wire 15 adheres to the outer peripheral surface of the winding jig 21 at least when the wire 15 is wound with the predetermined tension (load F). Therefore, by winding the wire 15 with such a predetermined tension (load F), a gap is prevented from occurring between the wire 15 and the winding jig 21, and the wire 15 can be wound around the winding jig 21 without any gaps.

The end of the wire 15 after winding is cut to a predetermined length corresponding to the first lead 12 and the second lead 13, and the first electrode 31 and the second electrode 32 are laser welded to the cut ends, the end 12e of the first lead 12 and the end 13e of the second lead 13. The electrodes 31 and 32 may be joined after the coil section 10 is pulled out of the winding jig 21. However, when the electrodes 31 and 32 are formed by crushing the end of the wire 15, it is preferable to perform the crushing while the coil section 10 is wound around the winding jig 21.

Next, the coil section 10 with the winding section 11 wound around the winding jig 21 is pulled out by a pickup device (not shown) and removed from the winding jig 21. As a result, an air-core coil (winding section) such as that shown in FIG. 2B is obtained.

Next, the obtained air-core coil (coil portion 10) is sealed (encapsulated) in the element body 40. The element body encapsulation (exterior sealing) of the coil portion 10 is performed, for example, by arranging multiple coil portions 10 in a mold, injecting resin into the mold, hardening it, and then singulating. At this time, the coil portion 10 is placed in the mold so that the mounting surface 48 faces downward, so that the outer surfaces of the first electrode 31 and the second electrode 32 are arranged in a state flush with the mounting surface 48 of the element body 40. Note that the singulation into individual coil components may be performed immediately after the exterior sealing process, or may be performed after the subsequent terminal coating stripping process or plating process.

After the coil portion 10 has been sealed, polishing is performed to ensure that the first electrode 31 and the second electrode 32 are exposed to the outside. Polishing may be performed using a blade or by irradiating a laser. At this time, it is preferable to simultaneously polish the entire mounting surface 48 of the element body 40 to make the mounting surface 48 flat.

The coil component 1 can be manufactured using this method.

The coil component 1 of the present disclosure is manufactured by winding the wire 15 around a winding jig 21 formed with a cross-sectional shape that allows the wire 15 to fit tightly. This makes it possible to prevent a gap from occurring between the wound wire 15 and the winding jig 21 during manufacturing. Or, even if a gap does occur, it can be made small. As a result, the shape of the winding portion 11 can be stabilized.

In addition, in the present disclosure, since the shape of the winding portion 11 can be stabilized, variation in the characteristics of the coil component 1 can be prevented, and the inductance characteristics can be stabilized. In addition, the Q value can be improved or enhanced. In other words, according to the present disclosure, it is possible to stably provide coil components 1 with high characteristics and small variation in shape and characteristics.

As a result, in the coil component 1 of the present disclosure, a coil component with high characteristics can be obtained without increasing the size of the coil component (with the same size). In other words, if the characteristics are the same, the size of the coil component 1 can be reduced.

In addition, in the present disclosure, the shape of the winding section 11 is stable, which not only stabilizes the characteristics of the coil component 1, but also allows the sealing size of the winding section 11 (i.e., the size of the coil component 1) to be reduced. If there is variation in shape, it is necessary to ensure extra margin in the size of the coil component 1, but this is not necessary for the winding section 11 according to the present disclosure. As a result, the characteristics of the coil component 1, such as the inductance, become even more stable.

In addition, the stable shape of the winding portion 11 makes manufacturing easier. Furthermore, for example, when arranging the winding portion 11 for exterior sealing, the winding portion 11 can be arranged at high density, making manufacturing more efficient. As a result, it is also possible to reduce the manufacturing cost of the coil component 1.

In addition, in the coil component 1 of the present disclosure, the wire 15 can be wound in close contact with the winding jig 21, preventing the wire 15 from shifting, and in this respect, the shape of the winding portion 11 can be stabilized. As a result, variations in characteristics such as inductance can be prevented and reduced. In addition, because the wire 15 is prevented from shifting while wound around the winding jig 21, when the end of the wire 15 is crushed to form an electrode, variations in the shape and size of the formed electrode can also be suppressed.

An embodiment of the coil component according to the present disclosure will be described.
First, in order to confirm whether differences in the radius of curvature of the most curved point of the cross-sectional shape of the winding jig would result in differences in the variation in the shape of the windings manufactured by winding the wire, windings were formed using two types of winding jigs that had the same maximum length and width dimensions but differed only in the radius of curvature of the corners, and the inner diameter of the formed windings was measured.

To confirm whether the characteristics of the coil components are improved by differences in the radius of curvature of the most curved part of the cross-sectional shape of the winding jig, two types of winding parts were manufactured: one formed by simply winding wire around a winding jig having a roughly rectangular cross-sectional shape with chamfered corners, and the other formed by winding wire around a winding jig having a cross-sectional shape with corners formed into an arc with a sufficient radius of curvature according to the present disclosure, and their inductance and Q characteristics were measured.

The winding section 911 shown in FIG. 5A is a winding section (Cex.2) as a comparative example of the present disclosure, and is formed by winding the wire 15 around a winding jig 921 having a rectangular cross section. The winding section 931 shown in FIG. 5B is a winding section (Ex.2) as a first embodiment of the present disclosure, and is formed by winding the wire 15 around a winding jig 941 having a substantially rectangular cross section with corners formed in an arc shape with a predetermined radius of curvature. The winding section 951 shown in FIG. 5C is a winding section (Ex.3) as a second embodiment of the present disclosure, and is formed by winding the wire 15 around a winding jig 941 having a substantially rectangular cross section with corners formed in an arc shape with an even larger predetermined radius of curvature.

The dimensions of each winding jig 921 are as follows: the winding jig 921 of the comparative example (Cex.2) has a planar shape of 0.11 mm x 0.31 mm, and a cross-sectional shape with rounded corners (chamfered portions) of a radius of 20 μ. The winding jig 941 of the example 1 (Ex.2) has a planar shape of 0.113 mm x 0.32 mm, and a cross-sectional shape with corners formed into a 1/4 arc with a radius of 57 μ. The winding jig 961 of the example 2 (Ex.3) has a planar shape of 0.116 mm x 0.316 mm, and a cross-sectional shape with corners formed into a 1/4 arc with a radius of 58 μ.

The cross-sectional area of the inner space of the winding section 911 manufactured with the winding jig 921 of the comparative example (Cex.2), the winding section 931 manufactured with the winding jig 941 of the example 1 (Ex.2), and the winding section 951 manufactured with the winding jig 961 of the example 2 (Ex.3) are approximately the same.

When the inductance and Q characteristics of these windings 911, 931, and 951 were measured, there was almost no difference in inductance (not shown). On the other hand, as shown in FIG. 6, a clear and significant improvement in the Q characteristics was confirmed in the windings 931 of Example 1 (Ex.2) and the windings 951 of Example 2 (Ex.3) compared to the windings 911 of the comparative example (Cex.2).

The present disclosure is not limited to the above-described embodiments, and various arbitrary and suitable modifications are possible.
For example, the cross-sectional shape of the winding jig is not limited to the shape of the above-mentioned embodiment. As long as there are at least three first arcs having a predetermined radius and a predetermined central angle that allow the wire to be tightly wound, the cross-sectional shape of the winding jig can be a shape that allows the wire to be tightly wound. The winding jig according to the present disclosure may have any such shape, and the scope of the present disclosure includes coil components having an inner circumference shape that conforms to the cross-sectional shape of such a jig.

For example, if three first arcs are connected in sequence with straight lines that are tangent to them, a so-called "rice ball shape" with rounded corners and a roughly triangular shape is formed. Even if the cross-sectional shape of the winding jig is made into such a "rice ball shape," it is possible to wind the wire around the circumference without creating gaps.

The winding jig may be a winding jig 221 having a substantially rectangular cross section in which the four corners are formed into arc-shaped corners 223 with respect to a rectangle (virtual rectangle) 222, as shown in FIG. 2C. In this cross-sectional shape, the arc-shaped corners 223 correspond to the first arcs according to the present disclosure, and the four first arcs are connected by straight connection lines. In this winding jig 221, the arc-shaped corners 223 are formed as arcs having a predetermined radius and a predetermined central angle that take into account the ease of bending of the wire as described above, that is, with which the wire can be tightly wound, so that the wire 15 is tightly wound around the winding jig 221 at the arc-shaped corners 223. As a result, the gap between the winding section 211 and the winding jig 221 is reduced, and an air-core coil 210 as shown in FIG. 2D is obtained.

2C, a small gap 218 is generated between the inner circumferential surface 217 of the winding portion and the winding jig 221 in the straight-line cross-sectional area of the winding jig 221, particularly in the straight-line area corresponding to the long side of the imaginary rectangle 222. However, compared to the case where the wire 15 is wound around a winding jig with a normal rectangular cross-section, the gap 218 is small, and the shape can be stabilized even in the case of the FIG. 2C. In addition, the formation of such a gap 218 between the inner circumferential surface 217 of the winding portion and the winding jig 221 has the effect of making it easier to pull out the winding portion 211 from the winding jig 221. The radius of the arc-shaped corner 223 can be increased to 1/2 the width Ls of the short side of the imaginary rectangle 222.

The winding jig may be a winding jig 321 as shown in FIG. 2E. The winding jig 321 has a shape in which the portions corresponding to the long sides of the imaginary rectangle further protrude outward compared to the winding jig 221 shown in FIG. 2C. That is, the winding jig 321 has four corners formed by four arc-shaped corners 323 corresponding to the first arc according to the present disclosure with respect to the imaginary rectangle 322, and the portions corresponding to the long sides of the imaginary rectangle 322 have a cross-sectional shape in which the portions protrude in a triangular shape by two straight inclined sides 325, 325. By using such a winding jig 321, an air-core coil 310 as shown in FIG. 2F can be obtained.

In this shape, the overhanging portion 324 is formed at the long side of the imaginary rectangle 322 and corresponds to the position where the wire 15 floats from the circumferential surface of the winding jig (gap 218 in FIG. 2C), so the gap 318 between the inner circumferential surface 317 of the winding portion and the winding jig 321 can be made smaller than the gap 218 of the winding portion 211 shown in FIG. 2C. In addition, even in this type of winding portion 311, the gap 318 is formed between the inner circumferential surface 317 of the winding portion and the winding jig 321, which makes it easier to pull out the winding portion 311 from the winding jig 321. In addition, in the winding jig 321, the radius of the arc-shaped corner portion 323 can be increased to 1/2 the width Ls of the short side of the imaginary rectangle 322.

In addition, in the winding jigs 221, 321 shown in Figures 2C and 2E, the connecting lines connecting the arc-shaped corners 223, 323 of the corners may be configured as curves, combinations of two or more curves, combinations of three or more straight lines, combinations of any number of straight lines and curves, etc. In any case, when applying a curve, it is preferable to apply a curve having a larger radius of curvature than the radius of curvature of the arc-shaped corners 223, 323 in order to eliminate or reduce the gap between the winding jigs 221, 321 and the winding parts 211, 311.

When using a straight line, it is preferable that the straight line be tangent to other straight lines or curves when connected. However, the straight line does not necessarily have to be tangent to other straight lines or curves, as long as it is connected to other straight lines or curves at an angle that reduces the gap between the wire being wrapped.

Furthermore, the present disclosure is not limited to a configuration in which a wire is wound around a winding jig. It can be suitably applied to any electronic component element that is manufactured in close contact with the periphery of a winding jig.

REFERENCE SIGNS LIST 1... coil component 10, 210, 310... coil portion 11, 211, 311, 911, 931, 951... winding portion 12... first lead 13... second lead 12e, 13e... lead end portion 15... wire 17, 217, 317... winding portion inner peripheral surface 19, 219, 319... winding portion inner space portion 218, 318... gap 31... first electrode 32... second electrode 38... connection portion 40... element body 48... mounting surface 20... winding base portion 21, 221, 321, 921, 941, 961... winding jig 26... base 222, 322... imaginary rectangle 223, 323... arc-shaped corner portion 324... protruding portion 325... inclined side 81... horizontal work table 82... pressing and holding members P1 to P8... connection points _A11 to _A14 ... first circular arcs _A21 , _A22 ... second circular arcs _A31 , _A32 ... third circular arcs _C11 to _C14 ... centers of first circular arcs _C21 , _C22 ... centers of second circular arcs _C31 , _C32 ... centers of third circular arcs

Claims (14)

A coil having a winding portion formed by winding a wire,
an inner peripheral shape of a cross section perpendicular to a winding axis of the winding portion has a shape including at least three first arcs and a plurality of connection lines connecting adjacent first arcs;
A coil, wherein the at least three first arcs are each an arc having a predetermined radius and a predetermined central angle about which the wire can be bent. The coil according to claim 1, wherein each of the multiple connection lines is composed of one or more straight lines, one or more curved lines, or a combination of one or more of the straight lines and one or more of the curved lines, and the curved lines have a radius of curvature larger than the radius of any of the first circular arcs adjacent to the curved lines. The coil of claim 1, wherein at least three of the first arcs are tangentially connected to the connection line. The plurality of connecting lines include
a pair of second arcs opposed along one of two orthogonal axes;
a pair of third arcs opposed along the other of the two orthogonal axes;
The first arc is disposed between the second arc and the third arc, a direction connecting a midpoint of the arc and a center point forms an angle of 45° with each of the two orthogonal axes, and the first arc is connected tangently to each of the second arc and the third arc.
The coil according to claim 1 . 5. The coil according to claim 4, wherein the inner peripheral shape of the cross section perpendicular to the winding axis of the winding portion has a shape such that the solutions of the following two equations are both positive.

An electronic component having a coil according to any one of claims 1 to 5. A winding jig for winding a wire, the cross section of which is as follows:
The peripheral shape is made up of at least three first arcs and a plurality of connection lines connecting adjacent first arcs,
A winding jig, wherein each of the at least three first arcs has a predetermined radius and a predetermined central angle within which the wire can be tightly fitted. The winding jig according to claim 7, wherein each of the multiple connection lines is composed of one or more straight lines, one or more curved lines, or a combination of one or more of the straight lines and one or more of the curved lines, and the curved lines have a radius of curvature larger than the radius of any of the first circular arcs adjacent to the curved lines. The winding jig according to claim 7, wherein at least three of the first arcs are tangentially connected to the connection line. The winding jig according to claim 7, wherein the cross section of the winding jig is substantially rectangular with the four first arcs arranged at the four corners. The winding jig according to claim 8, wherein at least one of the connection lines connecting the first arcs is a combination of a plurality of the straight lines or one or more of the curves projecting outward. A winding jig for winding a wire, the cross section of which is as follows:
a pair of second arcs opposed along one of two orthogonal axes;
a pair of third arcs opposed to each other along the other of the two orthogonal axes;
four first arcs each disposed between the second arc and the third arc, each having a direction connecting a midpoint of the arc to a center point that forms an angle of 45° with each of the two orthogonal axes, and each connected tangently to the second arc and the third arc;
The winding jig has an outer periphery having a shape consisting of: The winding jig according to claim 12, wherein the cross section of the winding jig has a shape such that solutions to the following two equations are both positive.

A method for manufacturing an electronic component, comprising a step of winding a wire around a winding jig according to any one of claims 9 to 13.

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