Winding bobbin and coil component

Abstract

To provide a winding bobbin capable of suppressing variations in coil height.SOLUTION: A winding bobbin 1 is formed in a ring shape, has an internal space 3 for accommodating a ring-shaped core 2, and has a coil C wound around its outer periphery, and two outer end faces 4A, 5A facing opposite each other in at least the axial direction S1 along the central axis are outer curved surfaces 10 that are curved so as to bulge in the axial direction S1 in a cross section perpendicular to the circumferential direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a winding bobbin and a coil component. [Background technology]

[0002] Patent Document 1 discloses a winding bobbin (hereinafter simply referred to as a bobbin) that constitutes a common mode choke coil, which is a type of coil component. The bobbin is formed in a ring shape with an internal space for accommodating a ring-shaped ferrite core. A coil is wound around the outer periphery of the bobbin.

[0003] In Patent Document 1, the cross section of the ring-shaped ferrite core perpendicular to the circumferential direction of the ferrite core is rectangular. Also, the cross section of the bobbin perpendicular to the circumferential direction of the ring is rectangular to match the cross section of the ferrite core, i.e., the outer periphery of the bobbin around which the coil is wound has a rectangular cross section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-066635 Summary of the Invention [Problem to be solved by the invention]

[0005] This type of coil component is sometimes housed in a low-height housing. However, when the coil is wound around the outer periphery of a bobbin having a rectangular cross-section, the coil can get caught or slip irregularly at the four corners of the rectangle. This can easily cause variations in the height of the coil wound around the bobbin.

[0006] Furthermore, when manually winding the coil around the bobbin, it is difficult to determine whether the coil is wound evenly, which also tends to cause variations in the height of the coil wound around the bobbin.

[0007] Here, the height of the coil wound around the bobbin refers to the length of the coil protruding from the bobbin in the axial direction of the ring-shaped bobbin. If there is variation in the height of the coil, it may not be possible to store it in a low-height housing, or the stored coil may interfere with the housing and cause an electrical short circuit.

[0008] It is possible to avoid the above problem by reducing the overall height of the ferrite core and the winding bobbin in the coil component, but this is not preferable because it makes it difficult to achieve the desired characteristics of the coil component.

[0009] The present invention has been made in view of the above circumstances, and has an object to provide a winding bobbin and a coil component including the same that can suppress variations in coil height. [Means for solving the problem]

[0010] One aspect of the present invention is a winding bobbin that is formed in a ring shape, has an internal space that accommodates a ring-shaped core, and has a coil wound around its outer circumference, and at least two outer end faces that face opposite each other in an axial direction along the central axis are outer curved surfaces that are curved so as to bulge in the axial direction in a cross section perpendicular to the circumferential direction.

[0011] Another aspect of the present invention is a coil component including the winding bobbin, a ring-shaped core accommodated in the internal space of the winding bobbin, and a coil wound around an outer periphery of the winding bobbin. [Effects of the Invention]

[0012] The winding bobbin of the present invention can suppress or prevent the appearance of corners on the outer end surface around which the coil is wound, and can prevent the coil from getting caught or slipping irregularly when winding the coil on the outer end surface. As a result, the winding bobbin of the present invention can suppress variations in the height of the coil wound around the outer end surface. Furthermore, in the winding bobbin of the present invention, the outer end surface is an outer curved surface that bulges in the axial direction, making it easy to visually check whether the wound coil is floating relative to the outer end surface. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of a coil component according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is an enlarged view of part III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of a coil component according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] First Embodiment Hereinafter, a winding bobbin according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the winding bobbin 1 of this embodiment is formed in a ring shape around an axial direction S1 along a central axis O. In the following description, the circumferential direction, which is the ring direction of the winding bobbin 1, is indicated by the symbol S2, and the radial direction of the winding bobbin 1 is indicated by the symbol S3. In addition, in the following description, expressions such as upper and lower sides in the drawing along the axial direction S1 are used, but these are directions within the drawing, and it goes without saying that the up and down directions will change if the orientation of the winding bobbin 1 changes.

[0015] 2 and 3, the winding bobbin 1 has an internal space 3 that houses a ring-shaped core 2. A coil C is wound around outer end surfaces 4A, 5A (described later) of end walls 4, 5 that form the outer periphery of the winding bobbin 1. In addition, the core 2 housed in the winding bobbin 1 is formed rectangular in cross section perpendicular to the circumferential direction S2, so that the core end faces 2A, 2B located on the upper and lower sides of the axial direction S1 in the figure are flat. The above-described winding bobbin 1, core 2, and coil C constitute a coil component 100.

[0016] 2 and 3, the winding bobbin 1 has an upper end wall 4 and a lower end wall 5 along the axial direction S1. These end walls 4, 5 are formed with two outer end surfaces 4A, 5A that face outward and are opposite each other in the axial direction S1 along at least the central axis O (see FIG. 3). These outer end surfaces 4A, 5A are winding surfaces of the coil C, and as can be seen by referring to the cross-sectional view of FIG. 3 perpendicular to the circumferential direction S2, they form outer curved surfaces 10 that curve upward and downward in the axial direction S1.

[0017] Furthermore, two inner end faces 4B, 5B are formed inside these end walls 4, 5, facing each other at least in the axial direction S1 along the central axis O. These inner end faces 4B, 5B of these end walls 4, 5 become contact surfaces with the flat core end faces 2A, 2B of the core 2. That is, in Figures 2 and 3, the inner end faces 4B, 5B are formed flat. With this configuration, the winding bobbin 1 has an outer curved surface 10 where the outer end faces 4A, 5A of the end walls 4, 5 bulge outward, so that the bobbin 1 is formed into a shape with an uneven thickness with a thick central portion.

[0018] 2 and 3, an inner circumferential wall 6 and an outer circumferential wall 7 are provided at side positions on the radial direction S3 side of the winding bobbin 1. The inner circumferential wall 6 is located inside the outer end faces 4A, 5A in the radial direction S3 and has an inner circumferential surface 6A facing inward. The outer circumferential wall 7 is located outside the outer end faces 4A, 5A in the radial direction S3 and has an outer circumferential surface 7A facing outward.

[0019] The inner peripheral surface 6A of the inner peripheral wall 6 and the outer peripheral surface 7A of the outer peripheral wall 7 extend linearly along the axial direction S1 in a cross section perpendicular to the circumferential direction S2. This allows the inner peripheral wall 6 and the outer peripheral wall 7, each with a uniform wall thickness, to be formed on both sides of the rectangular internal space 3 of the winding bobbin 1. Furthermore, the inner peripheral surface 6A of the inner peripheral wall 6 and the outer peripheral surface 7A of the outer peripheral wall 7 do not form curved surfaces that are continuous with the outer end surfaces 4A, 5A of the end walls 4, 5. As a result, the inner peripheral surface 6A and the outer peripheral surface 7A are spaced apart from the coil C wound around the outer end surfaces 4A, 5A and are out of contact with the coil C.

[0020] In the coil device 100 configured as described above, the two outer end faces 4A, 5A of the winding bobbin 1, which form the winding surfaces of the coil C, form outer curved surfaces 10 that bulge outward. This makes it possible to suppress or prevent corners from appearing on the outer periphery of the winding bobbin 1. As a result, in the coil device 100, when the coil C is wound around the outer periphery of the winding bobbin 1, it is possible to suppress the coil C from getting caught or slipping irregularly on the outer periphery of the winding bobbin 1. As a result, in the coil device 100, it is possible to effectively suppress variations in the height of the coil C wound around the winding bobbin 1.

[0021] Furthermore, in the coil device 100, the outer end faces 4A, 5A of the winding bobbin 1 form outer curved surfaces 10 that bulge in the axial direction S1, making it easy to visually check whether the wound coil C is floating above the outer end faces 4A, 5A. This makes it easy to notice variations in the height of the coil C during the manufacturing stage of the coil device 100, thereby improving the yield in post-manufacturing inspections.

[0022] Furthermore, in the coil device 100, in a cross section perpendicular to the circumferential direction S2, an inner circumferential surface 6A located inside the outer end faces 4A, 5A and an outer circumferential surface 7A located outside the outer end faces 4A, 5A are formed so as to extend linearly in the axial direction S1. As a result, in the coil device 100, the dimension of the winding bobbin 1 in the radial direction S3 can be kept small compared to when the outer periphery of the winding bobbin 1 around which the coil C is wound is entirely composed of curved surfaces, i.e., compared to when the cross-sectional shape of the winding bobbin 1 is a perfect ellipse or circle. In other words, the winding bobbin 1 can be made compact. This allows the coil device 100, including the winding bobbin 1, to be made smaller.

[0023] Furthermore, in the coil device 100, it is possible to suppress variations in the height of the coil C wound around the winding bobbin 1, and therefore it is possible to keep the height of the coil device 100 low.

[0024] Second Embodiment Hereinafter, a winding bobbin according to a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and common explanations will be omitted.

[0025] As shown in FIG. 4, in a coil device 101 of the second embodiment, the shape of a core 12 housed in an internal space 13 of a winding bobbin 11 is different from the core shape of the first embodiment. That is, the core 12 housed in the internal space 13 of the winding bobbin 11 has two core end faces 12A, 12B facing opposite each other in the axial direction S1, which form a convex core curved surface 20 that curves in a cross section perpendicular to the circumferential direction S2 and bulges in the axial direction S1.

[0026] These curved core end faces 12A, 12B of the core 12 contact two end walls 14, 15 located on the upper and lower sides of the winding bobbin 11 in the figure. In the winding bobbin 11, the end wall 14 on the upper side in the axial direction S1 in the drawing has an outer end surface 14A facing outward and an inner end surface 14B facing inward. The inner end surface 14B contacts the core end surface 12A of the core 12. In addition, in the winding bobbin 11, the end wall 15 on the lower side in the axial direction S1 in the drawing has an outer end surface 15A facing outward and an inner end surface 15B facing inward. The inner end surface 15B contacts the core end surface 12B of the core 12 (described below).

[0027] Here, the outer end faces 14A, 15A of the end walls 14, 15 of the winding bobbin 11 form outer curved surfaces 30 that bulge in the axial direction S1 and become the winding surfaces of the coil C. On the other hand, the inner end faces 14B, 15B of the end walls 14, 15 of the winding bobbin 11 form concave curved surfaces. The inner end faces 14B, 15B have approximately the same curvature as the curved surfaces of the core end faces 12A, 12B of the core 12, which are formed convexly. This allows the core end faces 12A, 12B of the core 12 to mate with and come into surface contact with the inner end faces 14B, 15B of the winding bobbin 11. In the winding bobbin 11, the outer end faces 14A, 15A and the inner end faces 14B, 15B of the end walls 14, 15 are parallel to each other, so that the end walls 14, 15 have a uniform thickness.

[0028] In the coil device 101 configured as described above, the core end faces 12A, 12B of the core 12 and the inner end faces 14B, 15B of the winding bobbin 11 are curved to correspond to each other, thereby making it possible to reduce the distance (indicated by symbol h in FIG. 4) along the axial direction S1 between the outer end faces 14A, 15A of the winding bobbin 11 and the core end faces 12A, 12B of the core 12. As a result, in the coil device 101, the thickness of the end walls 14, 15 of the winding bobbin 11 along the axial direction S1 can be made thinner than when the core end faces 2A, 2B of the core 2 are flat (see FIG. 3), and it is possible to prevent excess space from appearing in the portion of the winding bobbin 11 along the axial direction S1.

[0029] As a result, in the coil device 101, the thickness (indicated by symbol H in FIG. 4) in the axial direction S1 of the winding bobbin 11 that houses the core 12 having the same cross-sectional area orthogonal to the circumferential direction S2 can be reduced. That is, in the coil device 101, the thickness H in the axial direction S1 of the winding bobbin 11 can be reduced without changing the performance of the core 12, and the entire component including the winding bobbin 11 can be made smaller, particularly thinner in the axial direction S1.

[0030] Furthermore, the core 12 in the winding bobbin 11 has curved core end faces 12A, 12B that correspond to the inner end faces 14B, 15B of the winding bobbin 11. Therefore, in the coil device 101, the core 12 is held in the internal space 13 of the winding bobbin 11, while the thickness of the walls (end walls 14, 15, inner circumferential wall 6, and outer circumferential wall 7) of the winding bobbin 11 can be made uniform. This makes it possible to prevent defects such as sink marks caused by uneven wall thicknesses, even when the winding bobbin 11 is manufactured by molding.

[0031] (Variation) In the coil device 101 of the second embodiment, the outwardly curved core end faces 12A, 12B of the core 12 can be fully fitted and in surface contact with the concave inner end faces 14B, 15B of the winding bobbin 11. However, the core end faces 12A, 12B of the core 12 and the concave inner end faces 14B, 15B of the winding bobbin 11 may be in partial contact rather than in contact over the entire surface.

[0032] Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0033] 1 Winding bobbin 2 cores 2A Core end face 2B core end face 3. Interior space 4 End wall 4A outer end face 4B inner end face 5 End wall 5A outer end face 5B inner end face 6 Inner wall 6A inner surface 7 Outer wall 7A outer surface 10 Outer bay surface 11 ボビン for roll thread 12 コア 12A コアEnd face 12B コアEnd face 13 Interior Space 14 End wall 14A outer end face 14B inner end face 15 End wall 15A outer end face 15B inner end face 20 コアbay surface 30 Outer bay surface 100 コイル parts 101 コイル parts S1 axis direction S2 circumferential direction S3 radial direction C コイル O Center axis

Claims

1. A winding bobbin formed in a ring shape, having an internal space for accommodating a ring-shaped core, and having a coil wound around its outer periphery, A winding bobbin in which at least two outer end faces facing opposite each other in an axial direction along the central axis are outer curved surfaces that are curved so as to bulge in the axial direction in a cross section perpendicular to the circumferential direction.

2. an inner circumferential surface positioned inside the two outer end surfaces in the radial direction, and an outer circumferential surface positioned outside the two outer end surfaces, 2. The winding bobbin according to claim 1, wherein the inner peripheral surface and the outer peripheral surface extend linearly in the axial direction in a cross section perpendicular to the circumferential direction.

3. The winding bobbin according to claim 1 or 2; a ring-shaped core accommodated in the internal space of the winding bobbin; a coil wound around the outer periphery of the winding bobbin.

4. The coil component according to claim 3 , wherein two core end faces of the core facing opposite each other in the axial direction are core curved surfaces that are curved so as to bulge in the axial direction in a cross section perpendicular to the circumferential direction.

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