Bobbin and transformer device

Abstract

To provide a bobbin which is appropriate for adjusting leakage inductance and may also be downsized, and a transformer device.SOLUTION: A bobbin (10) used for a transformer device (1) comprises: a first cylindrical part (11) and a second cylindrical part (12) which are provided in parallel in a winding axis direction (15); and a separate part (13) protruding in a flange shape from a connection part of the first cylindrical part and the second cylindrical part. A primary coil (21) is wound around the first cylindrical part (11), and a second coil (22) is wound around the second cylindrical part (12). An inclined wall surface (131A) at an angle appropriate for a spiral gradient of the primary coil (21) is formed on a wall surface (131) of the separate part (13) on the side of the first cylindrical part, and an inclined wall surface (132A) at an angle appropriate for a spiral gradient of the secondary coil (22) is formed on a wall surface (132) on the side of the second cylindrical part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bobbin used as a main body of a transformer coil, and a transformer device using the same. [Background technology]

[0002] Conventionally, resonant converters have been used in chargers for plug-in hybrid vehicles (PHVs), etc. In such resonant converters, current noise components are reduced by utilizing resonance with a capacitor connected to a transformer, thereby improving conversion efficiency. In the transformer used in a resonant converter, it is extremely important to adjust design parameters such as the winding width, number of turns, bobbin diameter, and core gap to obtain the desired resonant inductance (excitation inductance and leakage inductance).

[0003] Conventionally, a bobbin used in such a transformer coil has been known that has a first cylindrical portion around which a primary winding is wound and a second cylindrical portion around which a secondary winding is wound, arranged side by side in the axial direction, and that has a separator portion that separates the first cylindrical portion from the second cylindrical portion in the axial direction (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-183524 [Patent Document 2] Japanese Patent Publication No. 2022-141446 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional bobbins described above, the separator section has a flat shape, which results in a dead space of one winding from the beginning to the end of each layer of winding (see Figure 4, for example). The existence of such dead space in the winding not only affects leakage inductance, but also poses an obstacle to making the bobbin smaller.

[0006] An object of the present invention is to provide a bobbin that is suitable for adjusting leakage inductance and the like and that can be made compact, and a transformer device including the bobbin. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a bobbin in which a first cylindrical portion around which a primary winding is wound and a second cylindrical portion around which a secondary winding is wound are connected and arranged side by side in the same axial direction, and the bobbin is provided with a separator portion that protrudes in a flange-like shape from the connecting portion between the first cylindrical portion and the second cylindrical portion to separate the first cylindrical portion from the second cylindrical portion and is provided along a direction intersecting the axial direction, and the separator portion has an inclined wall surface that is inclined at a predetermined angle with respect to a direction perpendicular to the axial direction.

[0008] With a bobbin of this configuration, part of the wall surface of the separation section that separates the first cylindrical section from the second cylindrical section is made into an inclined wall surface, thereby creating space for the winding to be wound along the separation section, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0009] Furthermore, it is preferable that the length of the inclined wall surface of the separate portion on the first cylindrical portion side of the bobbin matches the spiral gradient of the primary winding, and that the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding.

[0010] With a bobbin of this configuration, the length of the inclined wall surface of the separate portion on the first cylindrical portion side matches the spiral gradient of the primary winding, and the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding, thereby creating space for the primary winding to be wound along the wall surface of the separate portion, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0011] Furthermore, it is preferable that the length of the inclined wall surface of the separate portion on the second cylindrical portion side of the bobbin matches the spiral gradient of the secondary winding, and that the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding.

[0012] With a bobbin of this configuration, the length of the inclined wall surface of the separate portion on the second cylindrical portion side matches the spiral gradient of the secondary winding, and the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding, thereby creating space for the secondary winding to be wound along the wall surface of the separate portion, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0013] That is, it is preferable that the spiral gradient of the winding of the bobbin is relatively large on the side where the wire diameter of the winding is large and relatively small on the side where the wire diameter of the winding is small, and that the length of the inclined wall surface of the separating portion is set to match the spiral gradient so that it is relatively large on the cylindrical portion side where the wire diameter of the wound winding is large and relatively small on the cylindrical portion side where the wire diameter of the wound winding is small.

[0014] More specifically, it is preferable that the wire diameter of the secondary winding of the bobbin is set larger than the wire diameter of the primary winding, the spiral gradient of the winding is relatively large for the secondary winding and relatively small for the primary winding, and the length of the inclined wall surface of the separating portion is set to match the spiral gradient, with the second cylindrical portion side around which the secondary winding is wound being set relatively long and the first cylindrical portion side around which the primary winding is wound being set relatively short.

[0015] Furthermore, it is preferable that the inclination angle of the inclined wall surface of the separate portion on the first cylindrical portion side of the bobbin matches the spiral gradient of the primary winding, and that the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding.

[0016] With a bobbin of this configuration, the inclination angle of the wall surface of the separate portion on the first cylindrical portion side is adapted to the spiral gradient of the primary winding, and the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding, thereby creating space for the primary winding to be wound along the wall surface of the separate portion, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0017] Furthermore, it is preferable that the inclination angle of the inclined wall surface of the separate portion on the second cylindrical portion side of the bobbin matches the spiral gradient of the secondary winding, and that the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding.

[0018] With a bobbin of this configuration, the inclination angle of the wall surface of the separate portion on the second cylindrical portion side is adapted to the spiral gradient of the secondary winding, and the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding, thereby creating space for the secondary winding to be wound along the wall surface of the separate portion, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0019] The bobbin according to claim 1, further characterized in that the spiral gradient of the winding is relatively larger on the side where the wire diameter of the winding is larger and relatively smaller on the side where the wire diameter of the winding is smaller, and the length of the inclined wall surface of the separating portion is set to match the spiral gradient, being relatively larger on the cylindrical portion side where the wire diameter of the wound winding is larger and being relatively smaller on the cylindrical portion side where the wire diameter of the wound winding is smaller.

[0020] That is, the bobbin according to claim 1, characterized in that the wire diameter of the secondary winding is set larger than the wire diameter of the primary winding, the spiral gradient of the winding is relatively large for the secondary winding and relatively small for the primary winding, and the length of the inclined wall surface of the separating portion is set to match the spiral gradient, so that the side of the second cylindrical portion around which the secondary winding is wound is set relatively long and the side of the first cylindrical portion around which the primary winding is wound is set relatively short.

[0021] Furthermore, it is preferable that a part of the separate portion of the bobbin has a maximum thickness based on the difference in wire diameter between the primary winding and the secondary winding.

[0022] With this bobbin configuration, a portion of the separate section has a maximum thickness based on the difference in wire diameter between the primary winding and the secondary winding, so that even if the wire diameters or winding widths of the primary winding and secondary winding are different, dead space in the windings can be prevented.

[0023] In addition, a portion of the separate portion of the bobbin is composed of two thin plates spaced apart from each other along the axial direction, and the maximum thickness based on the difference in wire diameters is formed by setting the spacing between the two thin plates to a predetermined value.

[0024] With a bobbin having this configuration, it is possible to wind the wire while bending the inclined wall surface inward, thereby further preventing the occurrence of dead space for the winding.

[0025] The bobbin also has a rib that connects and reinforces the inner surfaces of the two thin plates in a predetermined manner, and the rib can regulate bending of the inclined wall surface toward the inner surface along the axial direction when the winding is wound around it.

[0026] With a bobbin of this configuration, it is possible to wind the wire without causing bending of the inclined wall surface toward the inner side.

[0027] Furthermore, it is preferable that the inclination angle of the inclined wall surface of the separate portion on the first cylindrical portion side of the bobbin matches the spiral gradient of the primary winding, and that the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding.

[0028] With a bobbin of this configuration, the inclination angle of the inclined wall surface of the separate portion on the first cylindrical portion side matches the spiral gradient of the primary winding, and the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding, thereby creating space for the primary winding to be wound along the wall surface of the separate portion, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0029] Furthermore, it is preferable that the inclination angle of the inclined wall surface of the separate portion on the second cylindrical portion side of the bobbin matches the spiral gradient of the secondary winding, and that the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding.

[0030] With a bobbin of this configuration, the inclination angle of the inclined wall surface of the separate portion on the second cylindrical portion side matches the spiral gradient of the secondary winding, and the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding, thereby creating space for the secondary winding to be wound along the wall surface of the separate portion, thereby enabling the dimension of the bobbin in the overall length direction (winding axis direction) to be shortened.

[0031] That is, it is preferable that the helical gradient of the winding of the bobbin is relatively large on the side where the wire diameter of the winding is large and relatively small on the side where the wire diameter of the winding is small, and that the inclination angle of the inclined wall surface of the separating portion is set to match the helical gradient so that it is relatively large on the cylindrical portion side where the wire diameter of the wound winding is large and relatively small on the cylindrical portion side where the wire diameter of the wound winding is small.

[0032] More specifically, it is preferable that the wire diameter of the secondary winding of the bobbin is set larger than the wire diameter of the primary winding, the spiral gradient of the winding is relatively larger for the secondary winding and relatively smaller for the primary winding, and the inclination angle of the inclined wall surface of the separating portion is set to match the spiral gradient so that the second cylindrical portion side on which the secondary winding is wound is set relatively larger and the first cylindrical portion side on which the primary winding is wound is set relatively smaller.

[0033] The present invention also provides a transformer device in which a primary winding and a secondary winding are wound around the bobbin, and a core that forms a magnetic path between the primary winding and the secondary winding is inserted into the body of the bobbin.

[0034] This transformer device employs a bobbin with an inclined wall surface for the separator and a space for the winding along the inclined wall surface, thereby enabling the size of the transformer device to be reduced and made more compact. Furthermore, by designing the position, thickness, and width of the separator according to specifications such as the number of turns and width of the winding, the leakage inductance of the transformer device can be more precisely adjusted.

[0035] In addition, in the transformer device, by inserting the core, a core gap is formed in a direction intersecting the axial direction, and a portion of the separator portion is arranged to include the core gap in a planar view, so that at least one of the first cylindrical portion and the second cylindrical portion is arranged to avoid the core gap in a planar view.

[0036] According to the transformer device having this configuration, it is possible to reduce the influence of eddy current loss due to leakage flux generated from the core gap.

[0037] Furthermore, in the transformer device, a core gap is formed in a direction intersecting the axial direction by inserting the core, and a portion of the separator portion is arranged to include the core gap in a planar view, so that one of the first cylindrical portion and the second cylindrical portion is arranged to avoid the core gap in a planar view, and the other of the first cylindrical portion and the second cylindrical portion is arranged so that the inclined wall surface intersects the core gap in a planar view.

[0038] According to the transformer device having this configuration, it is possible to reduce the influence of eddy current loss due to leakage flux generated from the core gap.

[0039] Furthermore, in the transformer device, by inserting the core, a core gap is formed in a direction intersecting the axial direction, and a part of the separate portion is arranged to include the core gap in a planar view. As a result, the first cylindrical portion, in which the wire diameter of the wound winding is set to be small, is arranged to avoid the core gap in a planar view, and the second cylindrical portion, in which the wire diameter of the wound winding is set to be large, is arranged so that the inclined wall surface intersects the core gap in a planar view.

[0040] According to the transformer device having this configuration, it is possible to reduce the influence of eddy current loss due to leakage flux generated from the core gap.

[0041] In addition, in the transformer device, a portion of the separation portion is composed of two thin plates spaced apart from each other along the axial direction, and the maximum thickness based on the difference in wire diameters is formed by setting the spacing between the two thin plates to a predetermined value.

[0042] According to the transformer device having this configuration, it is possible to wind the winding while bending the inclined wall surface inward, and it is possible to further prevent the occurrence of dead space for the winding.

[0043] The transformer device also has a rib that connects and reinforces the inner surfaces of the two thin plates in a predetermined manner, and the rib can regulate bending of the inclined wall surface toward the inner surface along the axial direction when the winding is wound.

[0044] This transformer device allows the windings to be wound without bending the inclined wall toward the inner surface, which fixes the positional relationship between the windings and the core gap and further reduces the effect of eddy current loss due to leakage flux from the core gap. [Effects of the Invention]

[0045] According to the present invention, by forming an inclined wall surface on a part of the separated part of the bobbin, it is possible to reduce the dead space of the winding and to miniaturize the bobbin and the transformer device using it. In addition, by designing the position, thickness, width, etc. of the separated part according to the specifications such as the number of turns and winding width of the winding, it is possible to more precisely adjust the leakage inductance of the transformer device. [Brief explanation of the drawings]

[0046] [Figure 1] FIG. 1 is a perspective view of an external appearance of a bobbin according to an embodiment of the present invention. [Figure 2] 2 is a top view of the bobbin as seen from the direction of the arrow A in FIG. 1. [Figure 3] 2 is a side view of the bobbin as seen from the direction of the arrow B in FIG. 1. [Figure 4] FIG. 10 is a side view showing the spiral gradient of the windings. [Figure 5] 2(a) is a side view of the transformer coil in which a winding is wound around the bobbin of FIG. 1, and FIG. 2(b) is a side view of a transformer coil according to the prior art. [Figure 6] FIG. 10 is a side view showing another modified example of the bobbin of the present invention. [Figure 7] FIG. 10 is a side view showing still another modified example of the bobbin of the present invention. [Figure 8]2 is a side view showing the state in which the inner surfaces of two thin plates of the bobbin of FIG. 1 are connected by a rib. [Figure 9] FIG. 10 is a side view showing a modified example of the bobbin of the present invention. [Figure 10] FIG. 10 is a side view showing the spiral gradient of the windings. [Figure 11] 1 is a schematic cross-sectional view of a transformer device according to an embodiment of the present invention; [Figure 12] 12 is a schematic cross-sectional view showing a state in which the inner surfaces of two thin plates of the bobbin are connected by a rib in the transformer device of FIG. 11. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0047] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each drawing, components that can be considered identical or equivalent are designated by the same reference numerals. Furthermore, in this specification, terms describing directions such as "upper," "lower," "front," and "rear" refer to directions in relative positional relationships in order to facilitate understanding of the invention, and are not to be construed as meaning absolute directions. Furthermore, in this specification, the term "axis" or "axial direction" simply refers to the bobbin winding axis and the direction of the winding axis, unless otherwise specified.

[0048] <Bobbin and transformer coil> As will be described later, the transformer device 1 according to the present invention is configured to include a transformer coil 2 in which a primary winding 21 and a secondary winding 22 are wound around a bobbin 10. First, an embodiment of the bobbin 10 used as the main body of such a transformer coil 2 will be described.

[0049] FIG. 1 is an external perspective view of a bobbin 10 according to one embodiment of the present invention. Also, FIG. 2 is a top view of the bobbin 10 as viewed from the direction of arrow A in FIG. 1, FIG. 3 is a side view of the bobbin 10 as viewed from the direction of arrow B in FIG. 1, FIG. 4 is a side view showing the spiral gradient of the winding, and FIG. 5 (a) is a side view of a transformer coil in which a winding is wound around the bobbin of FIG. 1, and FIG. 5 (b) is a side view of a transformer coil according to prior art. The body of the bobbin 10 is formed by juxtaposing a first cylindrical portion 11 forming a primary coil and a second cylindrical portion 12 forming a secondary coil in the direction of a winding axis 15 of the coil. The body of the bobbin 10 is integrally molded from an insulating material such as hard plastic.

[0050] Primary flange 141 is provided at one end of first cylindrical portion 11, perpendicular to winding shaft 15. Stand portion 151 is provided at the lower outer edge of primary flange 141, and groove-shaped winding guide portions 161a and 161b are provided on a bracket at the upper outer edge of primary flange 141.

[0051] At the other end of second tubular portion 12, secondary flange 142 is provided perpendicular to winding shaft 15. Similar to the primary flange, stand portion 152 is provided at the lower outer edge of secondary flange 142, and winding guide portions 162a, 162b are provided at the upper outer edge of secondary flange 142.

[0052] 1 to 5, a separate portion 13 that protrudes in a flange-like shape from the connecting portion between the first cylindrical portion 11 and the second cylindrical portion 12 is integrally formed with the bobbin 10 body. That is, the separate portion 13 is formed as a flange that divides the first cylindrical portion 11 and the second cylindrical portion 12 at approximately the center of the winding axis direction 15 and is provided along a direction intersecting the axial direction 15, more specifically, a direction 15' that is perpendicular to the axial direction 15.

[0053] 2, the separate portion 13 according to this embodiment has a shape that is bent in steps at the top and bottom of the body of the bobbin 10. That is, the separate portion 13 is characterized in that parts of the wall surfaces 131, 132 have inclined wall surfaces 131A, 132A that are inclined at a predetermined angle with respect to a direction 15' perpendicular to the axial direction 15. As a result, the axial positions that divide the first tubular portion 11 and the second tubular portion 12 differ between the front and rear of the body of the bobbin 10 via the inclined wall surfaces 131A, 132A.

[0054] To explain this separate part 13 in more detail, a length S1 of an inclined wall surface 131A formed on a part of a wall surface 131 of the separate part 13 on the first tubular part 11 side matches the helical gradient α' of the primary winding 21 (the helical gradient α' is the helical gradient in the direction perpendicular to the axial direction), and the helical gradient α' of the primary winding 21 corresponds to the wire diameter A of the primary winding 21. Similarly, a length S2 of an inclined wall surface 132A formed on a wall surface 132 of the separate part 13 on the second tubular part 12 side matches the helical gradient β' of the secondary winding 22 (the helical gradient β' is the helical gradient in the direction perpendicular to the axial direction), and the helical gradient β' of the secondary winding 22 corresponds to the wire diameter B of the secondary winding 22.

[0055] That is, the spiral gradients α', β' of the windings 21, 22 are relatively larger on the side where the wire diameters A, B of the windings 21, 22 are larger, and are relatively smaller on the side where the wire diameters A, B of the windings 21, 22 are smaller. The lengths S1, S2 of the inclined wall surfaces 131A, 132A of the separate portion 13 are set to match the spiral gradients α', β', so that they are relatively larger on the side of the tubular portions 11, 12 where the wire diameters A, B of the wound windings 21, 22 are larger, and are relatively smaller on the side of the tubular portions 11, 12 where the wire diameters A, B of the wound windings 21, 22 are smaller.

[0056] More specifically, the wire diameter B of the secondary winding 22 is set larger than the wire diameter A of the primary winding 21, and the spiral gradients α', β' of the windings 21, 22 are relatively larger for the secondary winding 22 and relatively smaller for the primary winding 21. The lengths S1, S2 of the inclined wall surfaces 131A, 132A of the separate portion 13 are set to match the spiral gradients α', β', so that the side of the second cylindrical portion 12 around which the secondary winding 22 is wound is set relatively longer, and the side of the first cylindrical portion 11 around which the primary winding 21 is wound is set relatively shorter.

[0057] Such a shape of separate portion 13 allows windings 21, 22 in contact with separate portion 13 to be tightly wound along inclined wall surfaces 131A, 132A. Therefore, space is secured for windings 21, 22 wound along separate portion 13, and the dimension of bobbin 10 in the overall length direction (winding axis direction) can be reduced compared to conventional bobbin body dimensions.

[0058] In this embodiment, the inclined wall surfaces 131A, 132A provided on the separate portion 13 are provided on the wall surfaces 131, 132 on both the first cylindrical portion 11 side and the second cylindrical portion 12 side, but as shown in Figures 6 and 7, the inclined wall surfaces may be provided on at least one of the first cylindrical portion 11 side or the second cylindrical portion 12 side.

[0059] In this embodiment, it is preferable that the separate portion 13 has a thick portion 13T at its front. The maximum thickness of this thick portion 13T is designed to correspond to the difference between the winding width of the primary winding 21 and the winding width of the secondary winding 22. Here, the "winding width" of the winding corresponds to the wire diameter if the winding is a single-core wire, and corresponds to twice the wire diameter if the winding is a paired wire. For example, the difference between the maximum and minimum thicknesses of the separate portion 13 can be set to match the difference in wire diameter or winding width between the primary winding 21 and the secondary winding 22. In this way, by forming the thick portion 13T in part of the separate portion 13, whose maximum thickness corresponds to the difference in wire diameter or winding width between the windings 21 and 22, it is possible to prevent dead space, which could not be eliminated with conventional flat separate portions, even if the wire diameter or winding width differs between the primary and secondary windings.

[0060] It is preferable to form multiple plates (thin plates 13Ta, 13Tb) by providing slits in the thickness portion 13T of the separate portion 13. In this case, reinforcing ribs may be formed in the spaces between the thin plates 13Ta, 13Tb formed in the multiple plate shape.

[0061] In other words, a part of the separate portion 13 is composed of two thin plates 13Ta, 13Tb spaced apart from each other along the axial direction 15, and by setting the spacing between the two thin plates 13Ta, 13Tb to a predetermined value, a thick portion 13T is formed having a maximum thickness based on the difference in each wire diameter.

[0062] This makes it possible to wind the windings 21 and 22 while bending the inclined wall surfaces 131A and 132A inward, thereby further preventing the dead space of the windings 21 and 22 from being generated.

[0063] Furthermore, as shown in FIG. 8, the bobbin 10 may have a rib 40 that connects and reinforces the inner surfaces of the two thin plates 13A and 13B in a predetermined manner, and the rib 40 may be configured to restrict bending of the inclined wall surfaces 131A and 132A toward the inner surface along the axial direction 15 when the windings 21 and 22 are wound around them.

[0064] With this configuration, it is possible to wind the windings 21 and 22 without causing bending of the inclined wall surfaces 131A and 132A toward the inner side.

[0065] In the bobbin 10 and the transformer coil 2 including the bobbin 10 of this embodiment, the lengths S1, S2 of the inclined wall surfaces 131A, 132A of the separate portion 13 match the spiral gradients α', β' of the windings 21, 22, and the spiral gradients α', β of the windings 21, 22 correspond to the wire diameters A, B of the windings 21, 22. This ensures more space for the windings 21, 22 and reduces dead space than in conventional bobbins where the separate portion 13 is flat. Therefore, the bobbin 10 and the transformer coil 2 can be made smaller in size in the overall length direction (winding axis direction).

[0066] In addition, by forming a thick portion 13T in a part of the separate portion 13 of the bobbin 10, which has a maximum thickness based on the difference in wire diameter or winding width between the primary winding 21 and the secondary winding 22, the dead space of the winding can be further reduced.

[0067] Furthermore, by designing parameters such as the position, thickness, or width of the separate portion 13 to match the specifications of the number of turns and winding width of the windings 21 and 22, the leakage inductance in the transformer coil 2 can be easily fine-tuned.

[0068] The bobbin 10 may also have the configuration shown in FIGS. 9 and 10, the inclination angle α (inclination angle α is the inclination angle with respect to the direction perpendicular to the axial direction 15) of the inclined wall surface 131A formed on a part of the wall surface 131 on the first cylindrical portion 11 side matches the spiral gradient α' of the primary winding 21, and the spiral gradient α' of the primary winding 21 corresponds to the wire diameter A of the primary winding 21. Similarly, the inclination angle β (inclination angle β is the inclination angle with respect to the direction perpendicular to the axial direction 15) of the inclined wall surface 132A formed on the wall surface 132 on the second cylindrical portion 12 side matches the spiral gradient β' of the secondary winding 22, and the spiral gradient β' of the secondary winding 22 corresponds to the wire diameter B of the secondary winding 22.

[0069] In other words, the spiral gradients α', β' of the windings 21, 22 are relatively larger on the side where the wire diameters A, B of the windings 21, 22 are larger, and are relatively smaller on the side where the wire diameters A, B of the windings 21, 22 are smaller, and the inclination angles α, β of the inclined wall surfaces 131A, 132A of the separate portion 13 are set to match the spiral gradients α', β', so that they are relatively larger on the side of the tubular portions 11, 12 where the wire diameters A, B of the wound windings 21, 22 are larger, and are relatively smaller on the side of the tubular portions 11, 12 where the wire diameters A, B of the wound windings 21, 22 are smaller.

[0070] More specifically, the wire diameter B of the secondary winding 22 is set larger than the wire diameter A of the primary winding 21, and the spiral gradients α', β' of the windings 21, 22 are relatively larger for the secondary winding 22 and relatively smaller for the primary winding 21. The inclination angles α, β of the inclined wall surfaces 131A, 132A of the separate portion 13 are set to match the spiral gradients α', β', so that the second cylindrical portion 12 side on which the secondary winding 22 is wound is set relatively larger, and the first cylindrical portion 11 side on which the primary winding 21 is wound is set relatively smaller.

[0071] 9 and 10, the inclination angles α and β of the wall surfaces 131A and 132A of the separate portion 13 are matched to the spiral gradients α' and β' of the windings 21 and 22, and the spiral gradients α' and β' of the windings 21 and 22 correspond to the wire diameters A and B of the windings 21 and 22. This ensures more space for the windings 21 and 22 and reduces dead space than in conventional bobbins where the separate portion 13 is flat. This allows the bobbin 10 and the transformer coil 2 to be made smaller in size along their overall length (in the winding axis direction).

[0072] <Transformer device> Next, a transformer device 1 using the above-described bobbin 10 will be described with reference to the schematic cross-sectional view of Fig. 11. The transformer device 1 according to this embodiment includes a transformer coil 2 formed by winding a primary winding 21 around the first cylindrical portion 11 of the bobbin 10 and winding a secondary winding 22 around the second cylindrical portion 12, and a pair of cores 31 and 32 inserted into the core hole 16 of the bobbin 10 body and forming a magnetic path between the primary winding 21 and the secondary winding 22.

[0073] Cores 31 and 32 are made of a magnetic material such as ferrite. Both cores 31 and 32 have an E-shaped cross section. Core 31 is inserted through core hole 16 on the primary side of bobbin 10, and core 32 is inserted through core hole 16 on the secondary side of bobbin 10. Their tip ends face each other with a predetermined gap between them, thereby forming a core gap 33. Core gap 33 is located at the connection between the primary coil and the secondary coil, i.e., approximately directly below separate portion 13.

[0074] The leakage inductance of the transformer device 1 is determined depending on the number of turns and winding width of the primary and secondary windings 21, 22, as well as the relative positions of the windings 21, 22, the cores 31, 32, the core gap 33, etc. In the transformer device 1 of this embodiment, the winding positions of the windings 21, 22 are uniformly adjusted by providing the inclined wall surfaces 131A, 132A on the separate portion 13 of the bobbin 10. Therefore, it is possible to provide a transformer device 1 having a leakage inductance that matches the design value with little variation error between products.

[0075] Furthermore, by appropriately designing parameters such as the position, thickness, or width of the separation portion 13 in accordance with specifications such as the number of turns and winding width of the windings 21 and 22, it is possible to more finely adjust the electrical characteristics of the transformer device 1, such as leakage inductance.

[0076] Here, in the transformer device 1, by inserting the cores 31 and 32, a core gap 33 is formed in a direction intersecting the axial direction 15, more specifically in a direction 15' perpendicular to the axial direction 15, and a portion of the separate portion 13 is arranged to include the core gap 33 in a planar view, so that at least one of the first tubular portion 11 and the second tubular portion 12 is arranged to avoid the core gap 33 in a planar view.

[0077] More specifically, in the transformer device 1, by inserting the cores 31 and 32, a core gap 33 is formed in a direction intersecting the axial direction 15, more specifically in a direction 15' perpendicular to the axial direction 15, and a portion of the separate portion 13 is arranged to include the core gap 33 in a planar view, so that one of the first cylindrical portion 11 and the second cylindrical portion 12 is arranged to avoid the core gap 33 in a planar view, and the other of the first cylindrical portion 11 and the second cylindrical portion 12 is arranged so that the inclined wall surfaces 131A and 132A intersect with the core gap 33 in a planar view.

[0078] More specifically, in the transformer device 1, by inserting the cores 31 and 32, a core gap 33 is formed in a direction 15' perpendicular to the axial direction 15, more specifically, in a direction intersecting the axial direction 15, and a part of the separate portion 13 is arranged to include the core gap 33 in a planar view. As a result, the first cylindrical portion 11, in which the wire diameter of the wound winding 21 is set small, is arranged to avoid the core gap 33 in a planar view, and the second cylindrical portion 12, in which the wire diameter of the wound winding 22 is set large, is arranged so that the inclined wall surface 132A intersects the core gap in a planar view.

[0079] According to the transformer device 1 having this configuration, it is possible to reduce the influence of eddy current loss due to leakage magnetic flux generated from the gap.

[0080] In addition, even in the transformer device 1 of this configuration, a portion of the separation portion 13 is composed of two thin plates 13Ta, 13Tb spaced apart from each other along the axial direction 15, and by setting the spacing between the two thin plates 13Ta, 13Tb to a predetermined value, a thick portion 13T is formed having a maximum thickness based on the difference in the wire diameters.

[0081] According to the transformer device 1 having this configuration, the windings 21 and 22 can be wound around the inclined wall surfaces 131A and 132A while bending them inward, and it is possible to further prevent dead space for the windings 21 and 22 from occurring.

[0082] Furthermore, as shown in FIG. 12, the transformer device 1 of this configuration has a rib 40 that connects and reinforces the inner surfaces of the two thin plates 13Ta and 13Tb in a predetermined manner, and the rib 40 can regulate the deflection of the inclined wall surfaces 131A and 132A toward the inner surface along the axial direction 15 when the windings 21 and 22 are wound around them.

[0083] With the transformer device 1 having this configuration, it is possible to wind the windings 21 and 22 without causing bending toward the inner surfaces of the inclined wall surfaces 131A and 132A. This fixes the positional relationship between the windings 21 and 22 and the core gap 33, further reducing the influence of eddy current loss due to leakage flux generated from the core gap 33.

[0084] In the transformer device 1 shown in Figures 11 and 12, the outer peripheries of a pair of cores 31, 32 face each other to form a back core that encompasses the transformer coil 2, but the present invention can also be applied to transformer devices that do not have such a back core. [Explanation of symbols]

[0085] α The inclination angle of the inclined wall of the first cylindrical section β Inclination angle of the inclined wall of the second cylindrical section α´ Primary winding spiral gradient β´ Secondary winding spiral gradient S1 Length of the inclined wall of the first cylindrical section S2 Length of the inclined wall of the second cylindrical section 1 Transformer device 2 transformer coils 10 bobbins 11 First cylinder part 12 Second cylinder part 13 Separate section 15 Winding shaft (winding axis direction) 15´ Orthogonal to the winding axis 16 Core hole location 21 Primary Winding 22 Secondary Winding 31, 32 cores 33 Core Gap 131 Wall surface on the first cylindrical section side 131A Slanted wall surface 132 Wall surface on the second cylindrical section side 132A Inclined wall 13T thick part 141 Primary side flange 142 Secondary side flange

Claims

1. A bobbin in which a first cylindrical portion around which a primary winding is wound and a second cylindrical portion around which a secondary winding is wound are connected in the same axial direction and arranged side by side, a separator portion that protrudes in a flange-like shape from a connection portion between the first cylindrical portion and the second cylindrical portion to separate the first cylindrical portion from the second cylindrical portion and is provided along a direction intersecting the axial direction, A bobbin in which at least one of the first cylindrical portion side and the second cylindrical portion side of the separate portion has an inclined wall surface that is inclined at a predetermined angle with respect to a direction perpendicular to the axial direction.

2. 2. The bobbin according to claim 1, wherein the length of the inclined wall surface of the separate portion on the first cylindrical portion side matches the spiral gradient of the primary winding, and the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding.

3. 2. The bobbin according to claim 1, wherein the length of the inclined wall surface of the separate portion on the second cylindrical portion side matches the spiral gradient of the secondary winding, and the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding.

4. the spiral gradient of the winding is relatively large on the side of the winding having a larger wire diameter and is relatively small on the side of the winding having a smaller wire diameter, 2. The bobbin according to claim 1, wherein the length of the inclined wall surface of the separating portion is set to be relatively large on the cylindrical portion side where the wire diameter of the wound winding is large, and relatively small on the cylindrical portion side where the wire diameter of the wound winding is small, in accordance with the spiral gradient.

5. a wire diameter of the secondary winding is set to be larger than a wire diameter of the primary winding, and a spiral gradient of the winding is relatively large in the secondary winding and relatively small in the primary winding; 2. The bobbin according to claim 1, wherein the length of the inclined wall surface of the separating portion is set to match the spiral gradient, such that the side of the second cylindrical portion on which the secondary winding is wound is relatively long, and the side of the first cylindrical portion on which the primary winding is wound is relatively short.

6. 6. The bobbin according to claim 1, wherein a part of the separate portion has a maximum thickness based on the difference in wire diameter between the primary winding and the secondary winding.

7. The bobbin according to claim 6, characterized in that a portion of the separation portion is composed of two thin plates spaced apart from each other along the axial direction, and the maximum thickness based on the difference in wire diameters is formed by setting a predetermined distance between the two thin plates.

8. 2. The bobbin according to claim 1, further comprising a rib that connects and reinforces the inner surfaces of the two thin plates in a predetermined manner, and the rib restricts deflection of the inclined wall surface toward the inner surface along the axial direction when the winding is wound.

9. 2. The bobbin according to claim 1, wherein the inclination angle of the inclined wall surface of the separate portion on the first cylindrical portion side matches the spiral gradient of the primary winding, and the spiral gradient of the primary winding corresponds to the wire diameter of the primary winding.

10. 2. The bobbin according to claim 1, wherein the inclination angle of the inclined wall surface of the separate portion on the second cylindrical portion side matches the spiral gradient of the secondary winding, and the spiral gradient of the secondary winding corresponds to the wire diameter of the secondary winding.

11. the spiral gradient of the winding is relatively large on the side of the winding having a larger wire diameter and is relatively small on the side of the winding having a smaller wire diameter, 2. The bobbin according to claim 1, wherein the inclination angle of the inclined wall surface of the separating portion is set to match the spiral gradient, so that the inclination angle is set relatively large on the cylindrical portion side where the wire diameter of the wound winding is large, and relatively small on the cylindrical portion side where the wire diameter of the wound winding is small.

12. a wire diameter of the secondary winding is set to be larger than a wire diameter of the primary winding, and a spiral gradient of the winding is relatively large in the secondary winding and relatively small in the primary winding; 2. The bobbin according to claim 1, wherein the inclination angle of the inclined wall surface of the separating portion is set to match the spiral gradient, so that the inclination angle is set relatively large on the second cylindrical portion side on which the secondary winding is wound, and relatively small on the first cylindrical portion side on which the primary winding is wound.

13. A transformer device comprising a primary winding and a secondary winding wound around the bobbin according to any one of claims 1 to 12, and a core that forms a magnetic path between the primary winding and the secondary winding inserted into the body of the bobbin.

14. By inserting the core, a core gap is formed in a direction intersecting the axial direction, and The transformer device according to claim 13, characterized in that, in a planar view, a portion of the separator portion is arranged to include the core gap, so that at least one of the first cylindrical portion and the second cylindrical portion is arranged to avoid the gap in a planar view.

15. By inserting the core, a core gap is formed in a direction intersecting the axial direction, and 14. The transformer device according to claim 13, wherein a portion of the separator is arranged to include the core gap in a planar view, so that one of the first cylindrical portion and the second cylindrical portion is arranged to avoid the core gap in a planar view, and the other of the first cylindrical portion and the second cylindrical portion is arranged so that the inclined wall surface intersects with the core gap in a planar view.

16. By inserting the core, a core gap is formed in a direction intersecting the axial direction, and 14. The transformer device according to claim 13, wherein a part of the separate portion is arranged to include the core gap in plan view, so that the first cylindrical portion, in which the wire diameter of the wound winding is set to be small, is arranged to avoid the core gap in plan view, and the second cylindrical portion, in which the wire diameter of the wound winding is set to be large, is arranged so that the inclined wall surface intersects the core gap in plan view.

17. The bobbin according to claim 13, characterized in that a portion of the separation portion is formed by two thin plates spaced apart from each other along the axial direction, and the maximum thickness based on the difference in wire diameters is formed by setting a predetermined distance between the two thin plates.

18. 14. The bobbin according to claim 13, further comprising a rib that connects and reinforces the inner surfaces of the two thin plates in a predetermined manner, and the rib restricts deflection of the inclined wall surface toward the inner surface along the axial direction when the winding is wound.

Images