Transformer, bobbin set, and method for manufacturing transformer

Abstract

This transformer (100) comprises: a bobbin (30) that extends in a winding axis direction; a first coil (11); a second coil (12); an interlayer tape (50); and one or more creepage surface tapes (60). The first coil (11) is wound inside among multiple coils (10) wound in layers about the bobbin (30). The second coil (12) is wound outside of the first coil (11). The interlayer tape (50) is wound between the first coil (11) and the second coil (12). The creepage surface tapes (60), when viewed in the winding axis direction, are wound outside of the first coil (11) or the second coil (12). At least some of the creepage surface tapes (60) and the interlayer tape (50) serve as an insulating tape (40) that is a single member.

Description

Transformer, bobbin set, and method for manufacturing the same

[0001] The present invention relates to a transformer, a bobbin set constituting such a transformer, and a method for manufacturing such a transformer.

[0002] Some transformers have multiple windings wound around a bobbin in layers. When multiple windings are wound in layers, they must be insulated from each other to prevent short circuits between the windings. Specifically, a creepage distance greater than or equal to a specified value must be maintained between the windings. Regarding this type of technology, Patent Document 1 (JP-A-2002-105025) discloses a transformer in which, as shown in FIG. 5 of the same document, three windings (21, 22, 23) are wound around a bobbin (12) in layers, with an interlayer tape (13) and an insulating barrier tape (14) disposed around the windings (21, 22, 23). Specifically, the three windings (21, 22, 23) are wound around the winding shaft of the bobbin (12), and both ends (21a, 22a, 23a) of the windings are pulled out to one axial side of the bobbin (12) (the right side in FIG. 5 of Patent Document 1). Interlayer tapes (13) are wound between the windings (21, 22, 23) wound around the bobbin (12). Furthermore, insulating barrier tapes (14) are wound around both outer sides of the windings (21, 22, 23) in the axial direction of the bobbin (12). That is, each winding (21, 22, 23) is wound in an area inside a pair of insulating barrier tapes (14). This configuration ensures a constant distance along the surface of the insulator between the first-layer winding (21) and the second-layer winding (22). The same applies to the winding between the second-layer winding (22) and the third-layer winding (23). For example, as shown in Figure 5 of Patent Document 1, one of the locations where the first-layer winding (21) and the second-layer winding (22) are close to each other along the surface of the insulator is between the left end of the first-layer winding (21) and the left end of the second-layer winding (22). The minimum length (creepage distance) along the surface of the insulator between the left end of the first-layer winding (21) and the left end of the second-layer winding (22) is equal to or greater than the sum of the widths of the insulation barrier tape (14) wound around the left side of the first-layer winding (21) and the second-layer winding (22). Another location where the first-layer winding (21) and the second-layer winding (22) are close to each other is between the right end of the first-layer winding (21) and the end (22a) of the second-layer winding (22) on the inner surface of the flange of the bobbin (12) (the position where the end is drawn out to the flange).The creepage distance between these two points is equal to or greater than the width of the insulating barrier tape (14) wound on the right side of the first-layer winding (21). Similarly, the creepage distance between the end (21a) of the first-layer winding (21) and the right end of the second-layer winding (22) is equal to or greater than the width of the insulating barrier tape (14) wound on the right side of the second-layer winding (22). The smallest of these creepage distances is the creepage distance between the windings (21) and (22). It is assumed that the end (21a) of the first-layer winding (21) and the end (22a) of the second-layer winding (22) are sufficiently separated in the depth direction of the drawing. In this way, by arranging the insulating barrier tape (14) outside the windings (21, 22, 23) in the axial direction of the bobbin (12), the windings (21, 22, 23) are spaced apart by the width of the insulating barrier tape (also called creepage tape), thereby ensuring the creepage distance between the windings.

[0003] Japanese Patent Application Publication No. 6-132144

[0004] As described above, the creepage distance can be secured by placing the insulating barrier tape on the outer side of the winding in the axial direction, but adding the step of winding the insulating barrier tape to the transformer manufacturing process increases the number of manufacturing steps for the transformer, which poses a problem of reduced transformer manufacturing efficiency.

[0005] The present invention has been made in view of the above-mentioned problems, and provides a transformer that requires few manufacturing steps while maintaining the creepage distance between windings at or above a specified value, a bobbin set for manufacturing such a transformer, and a method for manufacturing the transformer.

[0006] The transformer of the present invention has a bobbin extending in the winding axis direction, a first coil wound on the inside of multiple coils wound in layers around the bobbin, a second coil wound on the outside of the first coil, an interlayer tape wound between the first coil and the second coil, and one or more surface tapes wound on the outside of the first coil or the second coil in the winding axis direction, and at least a portion of the surface tape and the interlayer tape form a single insulating tape.

[0007] The bobbin set of the present invention includes a bobbin extending in a winding axis direction, and an insulating tape having a width equal to or greater than the length of a winding shaft portion in the winding axis direction, sandwiched between a pair of flange portions spaced apart from each other in the winding axis direction of the bobbin, wherein the insulating tape has a surface tape portion at one end of the insulating tape in the length direction, on the outside in the width direction, having a length equal to or greater than the circumferential length of the winding shaft portion.

[0008] The method for manufacturing a transformer of the present invention is a method for manufacturing a transformer having a bobbin extending in a winding axis direction, a first coil wound on the inside of multiple coils wound in layers around the bobbin, a second coil wound on the outside of the first coil, and an insulating tape wound around the bobbin, wherein the insulating tape has an interlayer tape portion wound between the first coil and the second coil, and a surface tape portion wound on the outside of the first coil or the second coil in the winding axis direction, and the interlayer tape portion and the surface tape portion are formed as a single insulating tape, and the method includes a first coil winding process in which the first coil is wound around the bobbin, an insulating tape winding process in which a portion of the interlayer tape portion and the surface tape portion are continuously wound around the bobbin, and a second coil winding process in which the second coil is wound on the outside of the interlayer tape portion.

[0009] According to the present invention, the surface tape and the interlayer tape are formed as a single insulating tape, so that the surface tape and the interlayer tape can be wound continuously, thereby reducing the number of manufacturing steps.

[0010] The above-mentioned objects, as well as other objects, features and advantages, will become more apparent from the preferred embodiments described below and the accompanying drawings.

[0011] 5(d) is a longitudinal cross-sectional view of a transformer according to a first embodiment taken along the dashed line in FIG. 5(d) and viewed in the direction of arrows I-I. 5(d) is a longitudinal cross-sectional view of a transformer according to a first embodiment taken along the dashed line in FIG. 5(d) and viewed in the direction of arrows II-II. 5(a) is a schematic diagram of a transformer for carrying out a step of winding a first surface tape in a manufacturing process of a transformer according to the first embodiment. 5(b) is a schematic diagram of a transformer with a first coil wound thereon. 5(a) is a schematic diagram of a transformer with an insulating tape disposed thereon in a manufacturing process of a transformer according to the first embodiment. 5(b) and 5(c) are schematic diagrams of a transformer with an insulating tape being wound thereon. 5(d) is a schematic diagram of a transformer with a second coil being wound thereon in a manufacturing process of a transformer according to the first embodiment. 5(b) is a schematic diagram of a transformer with an outer peripheral tape disposed thereon. 5(c) is a schematic diagram of a transformer after the second coil winding step has been completed. 5(d) is a schematic diagram of the external appearance of a transformer according to the first embodiment. 6A is a schematic diagram of the appearance of a transformer according to a second embodiment. (b) is a longitudinal cross-sectional view of the transformer according to the second embodiment taken along the dashed dotted line shown in FIG. 6A, viewed in the direction of arrows VI-VI. (a) is a schematic diagram of a transformer during a first coil winding step in a manufacturing process of a transformer according to the second embodiment. (b) is a schematic diagram of a transformer with a jig attached. (a) is a schematic diagram of a transformer with insulating tape arranged thereon in a manufacturing process of a transformer according to the second embodiment. (b) is a schematic diagram of a transformer after the first coil winding step has been completed. (a) is a schematic diagram of the appearance of a transformer according to a third embodiment. (b) is a schematic diagram of a transformer with insulating tape arranged thereon. (a) is a longitudinal cross-sectional view of the transformer according to the third embodiment taken along the dashed dotted line shown in FIG. 9A, viewed in the direction of arrows Xa-Xa. (b) is a longitudinal cross-sectional view of the transformer according to the third embodiment taken along the dashed dotted line shown in FIG. 9A, viewed in the direction of arrows Xb-Xb. 11A is a schematic diagram of the appearance of a transformer according to a fourth embodiment, and FIG. 11B is a cross-sectional view taken along the line XI-XI in FIG. 11A, viewed in the direction of the arrows. (a) is a schematic diagram of a transformer on which a partition tape is arranged during the manufacturing process of a transformer according to a fifth embodiment. (b) is a schematic diagram of a transformer in the middle of winding the partition tape.14(c) is a schematic diagram of a transformer after the second coil winding step has been completed. (a) and (b) are schematic diagrams of a transformer during the winding of a second tape in the manufacturing process of a transformer according to the fifth embodiment. (c) is a schematic diagram of a transformer during the winding of a third coil. (a) is a schematic diagram of a transformer in which a partition tape has been arranged in the manufacturing process of a transformer according to the fifth embodiment. (b) is a schematic diagram of a transformer after the winding of a partition tape has been completed. (c) is a schematic diagram of a transformer after the winding of a third coil has been completed. (d) is a schematic diagram of the appearance of a transformer according to the fifth embodiment. A longitudinal cross-sectional view of a transformer according to the fifth embodiment taken along the dashed line in FIG. 14(d) as viewed in the direction of arrows XV-XV. A longitudinal cross-sectional view of a transformer according to the fifth embodiment taken along the dashed line in FIG. 14(d) as viewed in the direction of arrows XVI-XVI.

[0012] The various components of the transformer and bobbin set of the present invention do not necessarily have to be independent entities. It is acceptable for multiple components to be formed as a single member, for one component to be formed from multiple members, for one component to be part of another component, or for part of one component to overlap with part of another component. Furthermore, while the method for manufacturing a transformer of the present invention may be described using multiple steps listed in order, the order of the steps does not limit the order or timing of performing the multiple steps. Therefore, when implementing the method for manufacturing a transformer of the present invention, the order of the multiple steps can be changed as long as it does not interfere with the content, and some or all of the timing of performing the multiple steps may overlap with each other.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, corresponding components are designated by the same reference numerals, and redundant description will be omitted where appropriate. In this embodiment, the winding axis direction of the bobbin 30 may be referred to as the left-right direction. Specifically, the side of the winding axis from which both ends of the first coil 11 are pulled out is referred to as the left side, and the side opposite the left side is referred to as the right side. For example, in FIG. 1 , the left side of the page corresponds to the left side of the transformer 100, and the right side corresponds to the right side. Also, in FIG. 3( a), the upper side corresponds to the left side, and the lower side corresponds to the right side. However, this definition is provided for convenience in order to easily explain the relative relationships between the components, and does not limit the orientation of a product embodying the present invention during manufacture or use. Furthermore, the term "flat" as used herein refers to a shape that is physically formed with a flat surface as the target, and naturally does not necessarily need to be a perfect geometric plane.

[0014] First Embodiment (Transformer)

[0015] First, an overview of the transformer 100 of this embodiment will be described. The transformer 100 has a bobbin 30 extending in the winding axis direction, a first coil 11, a second coil 12, an interlayer tape 50, and one or more surface creepage tapes 60. The first coil 11 is wound on the inside of the multiple coils 10 wound in layers around the bobbin 30. The second coil 12 is wound on the outside of the first coil 11. The interlayer tape 50 is wound between the first coil 11 and the second coil 12. The surface creepage tape 60 is wound on the outside of the first coil 11 or the second coil 12 when viewed in the winding axis direction. At least a portion of the surface creepage tape 60 and the interlayer tape 50 form a single insulating tape (integrated insulating tape 40).

[0016] Next, the transformer 100 of this embodiment will be described in detail using FIGS. 1 and 2. Note that hatching indicating cross sections of the coil 10 and bobbin 30 is omitted in FIGS. 1 and 2. The same applies to FIGS. 6(b), 10(a), 10(b), 11(b), 15, and 16. The same type of hatching is used to indicate cross sections of the same components. For convenience, FIGS. 1 and 2 show gaps between the first creeping tape 61b and the interlayer tape 50, and between the second creeping tape 62a and the outer tape 70. However, in reality, the tapes are in close contact with each other. The same applies to gaps between tapes (such as the interlayer tape 50, the creeping tape 60, the outer tape 70, the second interlayer tape 52, and the partition tape 80) in other embodiments described below.

[0017] The bobbin 30 is a component around which the coil 10 is wound. The bobbin 30 has a winding shaft portion 31, which is a portion around which the coil 10, the surface tape 60, the interlayer tape 50, and other tapes are wound. The length of the winding shaft portion 31 in the winding axis direction may be longer or shorter than the diameter of a flange portion 32 (described later). In this embodiment, the bobbin 30 has a pair of flange portions 32 spaced apart from each other in the winding axis direction. The flange portions 32 protrude radially beyond the circumferential surface of the winding shaft portion 31. Hereinafter, the radial direction refers to the direction extending radially from the axial center of the bobbin 30 toward the periphery. Hereinafter, the above-described direction will be referred to as the radial direction even when the cross section of the winding shaft portion 31 or the flange portion 32 is polygonal rather than circular. The flange portions 32 may be provided at both ends of the bobbin or midway along the length of the bobbin 30 in the winding axis direction. The winding shaft portion 31 is a region sandwiched between a pair of flange portions 32 (flange portion 32b and flange portion 32c). If the bobbin 30 does not have flange portion 32, the region of the bobbin 30 around which the first coil 11, the second coil 12, and the surface tape 60 are wound can be the winding shaft portion 31.

[0018] The bobbin 30 has terminals 33. In this embodiment, as shown in FIG. 3A, the bobbin 30 has multiple terminals 33 on the left side (upper side of the drawing) and the right side (lower side of the drawing). Specifically, four terminals on each side, for a total of eight terminals (terminals 331 to 338). Alternatively to this embodiment, as in a fourth embodiment described below, the bobbin 30 may have terminals 33 on only one side, either the left or right side. The number of terminals is not limited to eight, as long as it is four or more. The transformer 100 is, for example, surface-mounted on a mounting substrate (not shown). For example, as shown in FIGS. 1 and 2, the terminals 33 have parallel surfaces 33a parallel to the winding axis direction. The transformer 100 is disposed on the mounting substrate so that the parallel surfaces 33a are grounded to the mounting substrate. That is, the transformer 100 in this embodiment is a horizontal transformer disposed so that the winding axis portion 31 is parallel to the mounting substrate. The terminals 33 and the mounting substrate are joined by soldering or the like. In this embodiment, the terminals 33 have flat surfaces (parallel surfaces 33a) for surface mounting, but are not limited to this. For example, the terminals 33 may be pin-shaped terminals that are inserted into a mounting board.

[0019] The coil 10 is a linear member made of a conductive metal material such as copper. In this embodiment, the transformer 100 has a first coil 11 and a second coil 12 as the coils 10. In a fifth embodiment described later, the transformer 100 further has a third coil 13 as the coils 10. Two or more coils 10 are wound in layers around the bobbin 30. Here, "the coils 10 are wound in layers" means that the coil 10 (e.g., the first coil 11) wound on the lower layer (inner in the radial direction) and the coil 10 (e.g., the second coil 12) wound on the upper layer (outer in the radial direction) thereof at least partially overlap each other when viewed radially around the bobbin 30. Preferably, substantially the entire area of ​​the coil 10 (first coil 11) wound on the lower layer and substantially the entire area of ​​the coil 10 (second coil 12) wound on the upper layer overlap each other when viewed radially around the bobbin 30. Furthermore, the coil 10 wound on the lower layer side here simply means that the coil 10 is wound on the lower layer side of at least one other coil 10, and is not limited to being wound in the lowest layer. Similarly, the coil 10 wound on the upper layer side simply means that the coil 10 is wound on the upper layer side of at least one other coil 10, and is not limited to being wound in the highest layer. In the present embodiment, the first coil 11 is the coil 10 wound on the first layer of the winding shaft portion 31, and the second coil 12 is the coil 10 wound on the second layer of the winding shaft portion 31, but this is not limiting. For example, the first coil 11 may be the coil 10 wound on multiple layers of the winding shaft portion 31, and the second coil 12 may be the coil 10 wound on the layer immediately above the first coil 11.

[0020] The coil 10 is wound around a winding shaft 31, and both ends of the coil 10 are pulled out radially from the winding shaft 31 along the inner surface 32a of the flange 32. The portion of the coil 10 wound around the winding shaft 31 is called the winding portion (first winding portion 11b, second winding portion 12b in FIG. 1 ). The portion of the coil 10 pulled out from the winding shaft 31 to the terminal 33 is called the pull-out portion (first pull-out portion 11a, second pull-out portion 12a in FIG. 1 ). The pull-out portion is a partial length region of the coil 10 extending from one end of the winding portion to the other end wound around the terminal 33. The portion of the pull-out portion that is arranged along the winding axis is called the start portion or the return portion (first start portion 11e, second start portion 12e, first feedback portion 11f, second feedback portion 12f in FIGS. 1 and 2 ). The coil 10 has a start portion at one end and a return portion at the other end. In a manufacturing method of the transformer 100 described below, the coil 10 is arranged in the order of the start portion, the winding portion, and the feedback portion. Both ends of the coil 10 are wound around the base of the terminal 33, and the terminal 33 and the coil 10 are electrically connected. Instead of this embodiment, a winding terminal electrically connected to the terminal 33 may be provided on the bobbin 30, and both ends of the coil 10 may be wound around the winding terminal.

[0021] Either the first coil 11 or the second coil 12 may be a primary winding connected to the input side (power supply side), and either may be a secondary winding connected to the output side. When three or more coils 10 are wound around the bobbin 30 as will be described later in a fifth embodiment, the first coil 11 and the second coil 12 may both be connected to the input side, or both may be connected to the output side.

[0022] The interlayer tape 50 is a member made of an insulating sheet such as a resin. The insulating sheet constituting the interlayer tape 50 of this embodiment is configured by laminating a base layer and an adhesive layer. In the manufacturing process of the transformer 100 described below, the interlayer tape 50 is wound around the bobbin 30 (winding shaft portion 31) so that the adhesive layer is on the radially inner side. This allows the interlayer tape 50 to be wound while adhering to the first coil 11, the first surface tape 61, and the like already wound around the winding shaft portion 31. Here, "wound around the bobbin 30 (winding shaft portion 31)" includes not only being directly wound around the winding shaft portion 31 of the bobbin 30, but also being indirectly wound around the winding shaft portion 31 by being wound around the coil 10, tape, and the like already wound around the winding shaft portion 31. Other tapes, such as the surface tape 60 and second insulating tape described below, may also be made of the same insulating sheet as the interlayer tape 50 and may be configured of a base layer and an adhesive layer.

[0023] Here, "the interlayer tape 50 is wound between the first coil 11 and the second coil 12" means that the interlayer tape 50 is disposed over substantially the entire area sandwiched between the first coil 11 and the second coil 12 in the radial direction. Preferably, the interlayer tape 50 is also disposed over substantially the entire area sandwiched between the surface creeping tapes 60 (first surface creeping tape 61 and second surface creeping tape 62 described below) in the radial direction, and the area sandwiched between the surface creeping tape 60 and the coil 10. In other words, the interlayer tape 50 is disposed with a shape, dimensions, and position that encompasses substantially the entire area sandwiched between the first coil 11 and the first surface creeping tape 61, and the second coil 12 and the second surface creeping tape 62 in the radial direction. Specifically, the width of the interlayer tape 50 (the length in the winding axis direction) is equal to or greater than the length of the winding shaft portion 31 in the winding axis direction, and the length of the interlayer tape 50 in the length direction (the circumferential direction of the bobbin 30 when the interlayer tape 50 is wound around the winding shaft portion 31) is equal to or greater than the circumferential length of the winding shaft portion 31. The lengthwise dimension of the interlayer tape 50 and the widthwise dimension thereof may be any. That is, when the dimension of the winding shaft portion 31 in the winding axis direction is large, for example, the dimension of the interlayer tape 50 in the width direction (the direction of the winding axis when wound around the winding shaft portion 31) may be larger than the dimension in the lengthwise direction (the circumferential direction when wound around the winding shaft portion 31). The same applies to the other tapes. In addition, in this embodiment, the first coil 11, the second coil 12, and the surface tape 60 are arranged inward in the winding axis direction of a pair of left and right side end faces 50 a, 50 a extending in the lengthwise direction of the interlayer tape 50.

[0024] As described above, a portion of the lead-out portion of the coil 10 is disposed along the inner surface 32a of the flange portion 32. Therefore, in the present embodiment, where the first lead-out portion 11a or the second lead-out portion 12a is disposed, the width of the length of the winding shaft portion 31 in the winding axis direction over which the tape can be wound (the length in the winding axis direction) is shortened by the diameter of the first coil 11 or the second coil 12. Where the first lead-out portion 11a or the second lead-out portion 12a is disposed, the tape is wound while being partially bent radially outward to avoid the first lead-out portion 11a or the second lead-out portion 12a. The bent portion of the tape is not shown in FIGS. 1 and 2 . The bent portion is also not shown in the embodiments described below. In the fifth embodiment, the tape is wound while being bent radially outward to avoid the lead-out portion of the third coil 13 described below.

[0025] The surface creeping tape 60 is a member made of an insulating sheet such as a resin. The width of the surface creeping tape 60 is preferably equal to or less than half the length of the winding shaft portion 31 in the winding axis direction. The surface creeping tape 60 is wound outside (outside) the coil 10 (the first coil 11, the second coil 12, or the third coil 13 in the fifth embodiment) in the winding axis direction. Here, "wounding the surface creeping tape 60 outside the coil 10 in the winding axis direction" means that the surface creeping tape 60 and the coil 10 are wound in the same layer, and the surface creeping tape 60 is wound outside the coil 10 in the winding axis direction in the layer where the surface creeping tape 60 and the coil 10 are wound. "wounding the coil 10 and the surface creeping tape 60 in the same layer" means that the coil 10 and the surface creeping tape 60 partially overlap in the radial direction. In this embodiment, the surface creeping tape 60 is wound outside (left or right) the first coil 11 in the winding axis direction or outside (left or right) the second coil 12 in the winding axis direction. The surface creeping tape 60 may be wound around all of the above-mentioned locations (both outer sides in the winding axis direction of the first coil 11 and both outer sides in the winding axis direction of the second coil 12) as in the present embodiment. Alternatively, the surface creeping tape 60 may be wound around only some of the above-mentioned locations as in a third embodiment described later.

[0026] To avoid short circuits between the first coil 11 and the second coil 12, the first coil 11 and the second coil 12 must be spaced apart by a certain distance (prescribed value) or more at locations where they are close to each other. That is, the creepage distance between the first coil 11 and the second coil 12 must be maintained at a prescribed value or more. Here, the creepage distance refers to the minimum length along the surface of the insulator (the creepage tape 60 or the interlayer tape 50) between different coils 10 (e.g., the first coil 11 and the second coil 12). In the transformer 100, the first coil 11 and the second coil 12 are close to each other at multiple locations. For example, the right end 11d of the first winding portion 11b is close to the second lead-out portion 12a. The left end 12c of the second winding portion 12b is close to the first lead-out portion 11a. That is, by setting the creepage distance between the right end 11 d of the first winding portion 11 b and the second lead-out portion 12 a and the left end 12 c of the second winding portion 12 b and the first lead-out portion 11 a to a specified value or greater, the creepage distance between the entire length region of the first coil 11 and the entire length region of the second coil 12 can be maintained at a specified value or greater. The creepage distance between the entire length regions of the coils 10 is the distance along the surface of the insulator at the point where the coils are closest to each other. For example, as described above, there are multiple points where the first coil 11 and the second coil 12 are close to each other, and the creepage distance between the first coil 11 and the second coil 12 is the distance along the surface of the insulator at one of the multiple points where the first coil 11 and the second coil 12 are closest to each other.

[0027] In this embodiment, the creeping distance between the first coil 11 and the second coil 12 is maintained at a certain level by the surface creeping tape 60. Specifically, the lead-out portion of one coil is separated from the winding portion of the other coil, and the winding portion of one coil is separated from the lead-out portion of the other coil by the surface creeping tape 60. In this embodiment, as described above, the first coil 11 and the second coil 12 are close to each other between the right end 11 d of the first winding portion 11 b and the second lead-out portion 12 a, and between the left end 12 c of the second winding portion 12 b and the first lead-out portion 11 a. As shown in FIG. 1 , the creeping distance between the right end 11 d of the first winding portion 11 b and the second lead-out portion 12 a is equal to or greater than the sum of the width of the first creeping tape 61 b ​​wound on the right side of the first coil 11 and the overall thickness (radial length) of the interlayer tape 50 wound in one or more layers. 2, the creepage distance between the left end 12c of the second winding portion 12b and the first lead-out portion 11a is equal to or greater than the width of the second creepage tape 62a wound on the left side of the second coil 12. By making the width of the first creepage tape 61b and the second creepage tape 62a equal to or greater than the specified value, the creepage distance between the first coil 11 and the second coil 12 can be made equal to or greater than the specified value.

[0028] That at least a portion of the surface creeping tape 60 and the interlayer tape 50 form a single insulating tape (integral insulating tape 40) means that one or more of the surface creeping tapes 60 wound either outward (left or right) in the direction of the winding axis of the first coil 11 or outward (left or right) in the direction of the winding axis of the second coil 12 form a single component with the interlayer tape 50. That the surface creeping tape 60 and the interlayer tape 50 form a single component does not mean that the surface creeping tape 60 and the interlayer tape 50 are formed as separate components and then joined together, but rather that the surface creeping tape 60 and the interlayer tape 50 are a single component formed continuously without any seams.

[0029] By forming the surface creepage tape 60 and the interlayer tape 50 into a single, integrated insulating tape 40, when winding the interlayer tape 50 around the bobbin 30, the surface creepage tape 60 can be wound continuously before or after the interlayer tape 50. In other words, the steps of winding the interlayer tape 50 and the surface creepage tape 60 can be performed at the same time, thereby reducing the number of steps in manufacturing the transformer 100.

[0030] In this embodiment, the surface creeping tape 60 (second surface creeping tape 62) wound around the outside of the second coil 12 in the winding axis direction and the interlayer tape 50 form a single insulating tape (integrated insulating tape 40). More specifically, the second surface creeping tape 62 is disposed at one end of the interlayer tape 50 in the longitudinal direction, outward in the winding axis direction, to form the integrated insulating tape 40. Here, "the surface creeping tape 60 is disposed at one end of the interlayer tape 50 in the longitudinal direction outward in the winding axis direction" means that the surface creeping tape 60 is disposed at one end of the interlayer tape 50 in a position closer to either side in the winding axis direction than the center in the winding axis direction. Preferably, the surface creeping tape 60 is disposed inward in the winding axis direction of two sides (both sides) of the interlayer tape 50 extending in the longitudinal direction of the interlayer tape 50, but this is not limited thereto. A portion of the surface creeping tape 60 may be disposed outward in the winding axis direction of two sides of the interlayer tape 50 extending in the longitudinal direction of the interlayer tape 50. In this embodiment, a second surface-creeping tape 62 is arranged on each of the two outer sides in the winding axis direction at one end of the interlayer tape 50 in the longitudinal direction, and as shown in Figure 4(a) , the integrated insulating tape 40 is hollow on the inside in the winding axis direction at one end of the longitudinal direction.

[0031] Alternatively, the interlayer tape 50 and the second creeping tape 62 may be formed as separate members. In this case, for example, the interlayer tape 50 and the first creeping tape 61 form the integrated insulating tape 40 as a single member.

[0032] By forming the second surface creeping tape 62 and the interlayer tape 50 into a single component as described above, the winding efficiency of the second surface creeping tape 62 can be improved as follows. The surface creeping tape 60 is preferably wound on the outermost side (closer to the flange 32) of the winding shaft 31 in the winding axis direction. This is to ensure that the area around the winding shaft 31 around which the coil 10 can be wound is sufficiently large. Therefore, when starting to wind the surface creeping tape 60 in the winding process of the surface creeping tape 60 described below, it is necessary to precisely align the winding start position of the surface creeping tape 60 so that the surface creeping tape 60 is wound from the side (outside) sufficiently close to the flange 32 in the winding axis direction. By forming the second surface creeping tape 62 and the interlayer tape 50 into a single component, the second surface creeping tape 62 is wound immediately after the interlayer tape 50 is wound. By positioning the second surface creeping tape 62 at a desired position at one end of the interlayer tape 50, the effort of aligning the winding start position of the second surface creeping tape 62 can be eliminated.

[0033] In this embodiment, the surface creeping tape 60 (first surface creeping tape 61) wound on the outside of the first coil 11 in the winding axis direction and the interlayer tape 50 are separate members. Being separate members means that they may be separated from each other or may be in contact with each other. In this embodiment, the first surface creeping tape 61 and the interlayer tape 50 are adhered to each other via an adhesive layer. The first surface creeping tape 61 and the interlayer tape 50, which are separate members, may be made of the same material or different materials.

[0034] Because the first surface creeping tape 61 and the interlayer tape 50 are separate members, interference between the interlayer tape 50 and a wire supply unit (not shown) for winding the first coil 11 around the winding shaft unit 31 can be prevented when winding the first coil 11. Except when using a jig as in a second embodiment described below, it is desirable to wind the first surface creeping tape 61 before winding the first coil 11. This is because winding the first surface creeping tape 61 defines an area of ​​the winding shaft unit 31 around which the first coil 11 can be wound. The first coil 11 is wound around the winding shaft unit 31 by a wire supply unit such as a nozzle moving around the relatively outer side of the winding shaft unit 31 in the radial direction, as described below. Therefore, to avoid interference between the wire supply unit and other members, it is desirable that no other members, including the interlayer tape 50, be disposed in the space radially outside the winding shaft unit 31 when winding the first coil 11. If the interlayer tape 50 is a separate member from the first surface tape 61, there is no need to place the interlayer tape 50 in the space radially outside the winding shaft portion 31 when winding the first coil 11. In this way, if the first surface tape 61 and the interlayer tape 50 are separate members, interference between the wire supply portion and the interlayer tape 50 is prevented, and the first coil 11 can be wound around the winding shaft portion 31 efficiently.

[0035] Furthermore, because the first creeping tape 61 and the interlayer tape 50 are separate members, in the insulating tape winding step described below, the integrated insulating tape 40 is wound around the bobbin 30 starting from the interlayer tape 50 portion (interlayer tape portion 41). As will be described later in the second embodiment, if the first creeping tape 61 and the interlayer tape 50 are formed as one member, the winding start positions of the first creeping tapes 61a, 61b on both outer sides in the winding axis direction must be aligned with each other in the circumferential direction and the winding axis direction in order to wind the interlayer tape portion 41 without wrinkles. When the integrated insulating tape 40 is wound around the bobbin 30 starting from the interlayer tape portion 41, the above-mentioned step of aligning the first creeping tape 61 can be omitted.

[0036] In the present embodiment, both of the second creeping tapes 62 (second creeping tape 62a, second creeping tape 62b) arranged on the outer side of the second coil 12 in the winding axis direction are integrated with the interlayer tape 50, but this is not limited to this. For example, as in a third embodiment described later, the interlayer tape 50 and the creeping tape 60 wound around one side of the first coil 11 or the second coil 12 in the winding axis direction may form an integrated insulating tape 40.

[0037] As described above, a portion of the lead-out portion of the coil 10 is disposed along the inner surface 32a of the flange portion 32. Furthermore, tapes such as the interlayer tape 50 and the surface-creeping tape 60 are wound around the winding shaft portion 31 so as to avoid the portion of the lead-out portion disposed along the inner surface 32a. In Figures 4(a), 4(b), 4(c), 4(d), 5(a), 5(b), 5(c), and 5(d), the portion of the lead-out portion of the coil 10 that is disposed along the inner surface is not shown. Similarly, in the embodiments described below, the portion of the lead-out portion of the coil 10 that is disposed along the inner surface is not shown.

[0038] (Bobbin Set) The bobbin 30 and integrated insulating tape 40 according to this embodiment can also be provided as a bobbin set that does not include the coil 10. The bobbin set includes a bobbin 30 extending in the winding axis direction and an insulating tape (integrated insulating tape 40). The integrated insulating tape 40 has a width equal to or greater than the length of the winding shaft portion 31 in the winding axis direction, sandwiched between a pair of flange portions 32 spaced apart in the winding axis direction of the bobbin 30. The integrated insulating tape 40 has a creeping tape portion 42 with a length equal to or greater than the circumferential length of the winding shaft portion 31 on the outer side in the width direction at one end in the longitudinal direction of the integrated insulating tape 40. Here, the longitudinal direction of the integrated insulating tape 40 is the direction perpendicular to the width direction. In this embodiment, the creeping tape portion 42 is provided on both outer sides in the width direction at only one end in the longitudinal direction of the integrated insulating tape 40, but this is not limited thereto. The creeping tape portion 42 may also be provided on both ends in the longitudinal direction. Furthermore, the surface creeping tape portion 42 may be provided on only one of the outer sides in the width direction. The width of each of the surface creeping tape portions 42 is half or less of the width of the interlayer tape portion 41. In other words, the integrated insulating tape 40 has a wide interlayer tape portion 41 that is equal to or greater than the length of the winding axis direction of the winding shaft portion 31, and a narrow surface creeping tape portion 42 that is less than the width of the interlayer tape portion 41. The length of the interlayer tape portion 41 in the longitudinal direction is equal to or greater than the circumferential length of the winding shaft portion 31. The interlayer tape portion 41 and the surface creeping tape portion 42 are formed from a single member.

[0039] Using a manufacturing method for the transformer 100 described below, the integrated insulating tape 40 and the coil 10 are wound around the winding shaft portion 31 of the bobbin 30. Specifically, the integrated insulating tape 40 is wound so that the interlayer tape portion 41 is positioned between the two coils 10 and the creeping tape portion 42 is positioned outward in the winding axis direction of the coil 10. The integrated insulating tape 40 is wound around the winding shaft portion 31 from either end in the length direction.

[0040] The interlayer tape portion 41 and the surface tape portion 42 are formed as a single, integrated insulating tape 40, which allows the interlayer tape portion 41 and the surface tape portion 42 to be wound continuously. In other words, the integrated insulating tape 40 eliminates the need to wind the interlayer tape portion 41 and the surface tape portion 42 separately, thereby reducing the number of manufacturing steps for the transformer 100.

[0041] (Transformer Manufacturing Method) Hereinafter, a method for manufacturing the transformer of this embodiment (hereinafter sometimes referred to as the present method) will be described.

[0042] First, an overview of this method will be described. As described above, the transformer 100 has a bobbin 30 extending in the winding axis direction, a first coil 11, a second coil 12, and an insulating tape (integrated insulating tape 40). The first coil 11 is wound on the inner side (lower layer) of the multiple coils 10 wound in layers around the bobbin 30. The second coil 12 is wound on the outer side (upper layer) of the first coil 11. The integrated insulating tape 40 has an interlayer tape portion 41 wound between the first coil 11 and the second coil 12, and a creeping tape portion 42 wound outward in the winding axis direction of the first coil 11 or the second coil 12. The interlayer tape portion 41 and the creeping tape portion 42 are formed as a single insulating tape. This method includes a first coil winding process in which the first coil 11 is wound around the winding shaft portion 31, an insulating tape winding process in which a portion of the interlayer tape portion 41 and the surface tape portion 42 are continuously wound around the bobbin 30, and a second coil winding process in which the second coil 12 is wound around the outside of the interlayer tape portion 41.

[0043] Next, this method will be described in detail. First, as shown in FIG. 3( a), the first surface creeping tape 61 is wound on the outer side of the winding axis direction of the winding shaft portion 31. In this embodiment, the first surface creeping tape 61 is wound on both outer sides of the winding axis direction. In this embodiment, the first surface creeping tape 61 is wound in a clockwise direction when the bobbin 30 is viewed from the left side, but this is not limited to this. Not only the surface creeping tape 60, but also tapes such as the interlayer tape 50 and the second insulating tape may be wound in a clockwise direction or a counterclockwise direction when the bobbin 30 is viewed from the left side. The tapes may be wound in the same direction or in different directions. The surface creeping tape 60, such as the first surface creeping tape 61 and the second surface creeping tape 62, may be wound around the winding shaft portion 31 at least once, but may be wound two or more times. 1 and 2, the surface creeping tape 60 is preferably wound so that the overall height (height in the radial direction) of the wound surface creeping tape 60 is equal to or greater than the overall height of the coil 10 wound in the same layer. For example, when the first coil 11 is wound in only one layer, the overall height of the wound first surface creeping tape 61 is preferably equal to or greater than the diameter of the first coil 11.

[0044] In the first coil winding process, the first coil 11 is wound around the winding shaft 31 as shown in FIG. 3( b). Specifically, one end of the first coil 11 at the start of winding is wound around the base of the terminal 33 (e.g., terminal 332) on the left side (upper side of the drawing) and is pulled into the first surface tape 61a while contacting the inner surface 32a of the left flange 32b. The first coil 11 (first start portion 11e) is pulled out to the right side (lower side of the drawing) along the surface of the first surface tape 61a and wound from left to right around the winding shaft 31. In this embodiment, the first coil 11 is wound counterclockwise when viewing the bobbin 30 from the left side, but this is not limited thereto. The coil 10 may be wound clockwise or counterclockwise when viewing the bobbin 30 from the left side. Different coils 10 may be wound in the same direction or in different directions. The first coil 11 is wound inward in the winding axis direction relative to the first surface creeping tape 61. In this embodiment, the first surface creeping tapes 61 are wound on both outer sides in the winding axis direction, so the first coil 11 is wound between the pair of first surface creeping tapes 61 (first surface creeping tape 61a and first surface creeping tape 61b). In this embodiment, the first coil 11 is wound around the winding shaft portion 31 in only one layer, but this is not limited to this. As exemplified in a fifth embodiment described below, the first coil 11 may be wound around the winding shaft portion 31 in multiple layers. After winding to the right side, the first coil 11 is bent leftward and drawn out to the left terminal 33 (e.g., terminal 333). The first coil 11 is drawn outward in the radial direction along the inner surface 32a of the left flange portion 32b. One end of the first coil 11 is wound around the base of the terminal 333.

[0045] Generally, a winding device (not shown) is used to wind the coil 10. Specifically, a wire supply unit such as a nozzle for feeding wire in the winding device moves while rotating around the fixed bobbin 30, or the wire supply unit is fixed and the bobbin 30 itself rotates, thereby winding the wire around the outer periphery of the bobbin 30. In this embodiment as well, the coil 10 is wound around the bobbin 30 by the wire supply unit moving around the outside of the bobbin 30 in the radial direction.

[0046] In the insulating tape winding step, the integrated insulating tape 40 is wound. As described above, the integrated insulating tape 40 has an interlayer tape portion 41 and a creeping tape portion 42. In this embodiment, the interlayer tape portion 41 is the interlayer tape 50, and the creeping tape portion 42 is the second creeping tape 62. As shown in FIG. 4( a ), the integrated insulating tape 40 is wound starting with the interlayer tape portion 41, and a portion of the interlayer tape portion 41 and the creeping tape portion 42 are wound continuously. The interlayer tape portion 41 and the creeping tape portion 42 are each wound at least once around the winding shaft 31, and may be wound two or more times. "Continuously winding a portion of the interlayer tape portion 41 and the creeping tape portion 42" means that the step of winding at least a portion of the interlayer tape portion 41 and the step of winding the creeping tape portion 42 are performed consecutively. In the present embodiment, the winding of the surface creeping tape portion 42 follows the winding of a portion of the interlayer tape portion 41, but either the winding of the interlayer tape portion 41 or the winding of the surface creeping tape portion 42 may be performed first. For example, in a case where the first surface creeping tape 61 and the interlayer tape 50 form an integrated insulating tape 40, the winding of the surface creeping tape portion 42 follows the winding of the interlayer tape 50. In the present embodiment, after winding a portion of the interlayer tape portion 41 as shown in FIG. 4( b), the second coil 12 is pulled onto the winding shaft portion 31. After the second coil 12 is pulled onto the winding shaft portion 31, the remaining portion of the interlayer tape portion 41 is wound as shown in FIG. 4( c), and then the winding of the surface creeping tape portion 42 is continued as shown in FIG. 4( d).

[0047] When the second surface creeping tape 62 is wound after the second coil 12 is pulled into the winding shaft unit 31, a wire supply unit (not shown) for winding the second coil 12 is disposed radially outside the winding shaft unit 31 while the second surface creeping tape 62 is being wound. To avoid interference between the wound second surface creeping tape 62 and the wire supply unit, it is preferable to dispose the wire supply unit in the space radially outside the winding shaft unit 31, between the space radially outside the wound second surface creeping tape 62a and the space radially outside the wound second surface creeping tape 62b.

[0048] In the second coil winding process, the second coil 12 is wound around the bobbin 30. As shown in FIG. 4( b), one end of the second coil 12 is wound around the base of the right-side terminal 33 (e.g., terminal 336). The second coil 12 is arranged along the inner surface 32a of the right-side flange 32c and pulled into the interlayer tape portion 41. As shown in FIG. 5( a), the second coil 12 is wound in the region inside the flanges 32b, 32c and the second creeping tape 62 as viewed in the winding axis direction. In this embodiment, the second creeping tape 62 is wound on both outer sides in the winding axis direction, and the second coil 12 is wound from the right side (lower side in the drawing) to the left side (upper side in the drawing) in the region between the pair of second creeping tapes 62a, 62b. As shown in FIG. 5C, the second coil 12 wound to the left side is bent to the right at the boundary portion 12g, and the other end of the second coil 12 is wound around the base of the right terminal 33 (for example, terminal 337).

[0049] 5(b) and 5(d), after the second coil 12 is wound, a peripheral tape 70 (described later) is disposed and wound on top of the second coil 12. The peripheral tape 70 may be wound around the winding shaft portion 31 once, but may also be wound around the winding shaft portion 31 two or more times.

[0050] In this embodiment, as shown in FIG. 1 , a portion of the second coil 12 (second start portion 12 e) is disposed between the interlayer tape 50 and a surface creeping tape 60 (second surface creeping tape 62 b) formed of a single member with the interlayer tape 50 and wound outwardly of the second coil 12 in the winding axis direction. Specifically, a portion of the second coil 12 is disposed between the interlayer tape 50 and the surface creeping tape 60 wound on the same side as the side on which one end of the second coil 12 is wound. The second coil 12 is wound as follows, so that the second start portion 12 e is disposed between the interlayer tape 50 and the second surface creeping tape 62 b. When the interlayer tape portion 41 of the integrated insulating tape 40 is wound partway as shown in FIG. 4 ( b), the second coil 12, one end of which is wound around the terminal 33, is pulled inward in the winding axis direction onto the interlayer tape portion 41. 4(c), the integrated insulating tape 40 is wound so that the surface creepage tape portion 42 (second surface creepage tape 62b) is located on the upper layer side of the second coil 12 that has been pulled inward in the winding axis direction. As a result, the second starting portion 12e is located between the interlayer tape 50 and the second surface creepage tape 62b.

[0051] The second start portion 12e of the second coil 12 is disposed substantially parallel to the winding shaft portion 31, but in order to wind the second coil 12 around the winding shaft portion 31, the second coil 12 needs to be bent in either direction in the circumferential direction as shown in FIG. 4(d). That is, the second coil 12 is bent at a bend portion 12j between the second start portion 12e and the second winding portion 12b. By disposing the second surface creeping tape 62b on the upper layer side of the second start portion 12e, the second start portion 12e is sandwiched and fixed between the second surface creeping tape 62b and the interlayer tape 50. This allows the second coil 12 to be easily bent at the bend portion 12j.

[0052] The transformer 100 includes a second insulating tape (in this embodiment, the outer tape 70) wound around the outer (upper) side of a portion of the second coil 12 and including a wide portion having a width equal to or greater than the length of the winding shaft portion 31 of the bobbin 30 in the winding axis direction. The second insulating tape may be wound around the upper side of a portion of the second coil 12, or may be wound around the entire second coil 12. The wide portion is a wide, solid portion of the second insulating tape. The width of the wide portion refers to the longest length of the wide portion in the winding axis direction. The longitudinal length of the wide portion is equal to or greater than the circumferential length of the winding shaft portion 31, preferably equal to or greater than the circumferential length of the second coil 12 wound underneath the second insulating tape. In this embodiment, the entire second insulating tape (the outer tape 70) (including the portion where the notch 71, described below, is formed) is the wide portion, but this is not limited thereto. It is sufficient if only a portion of the second insulating tape is the wide portion. For example, when the second insulating tape is a partition tape 80 wound between the first and second layers of the second coil 12, as in the fifth embodiment described below, the partition tape 80 may have a surface tape portion 83 in addition to the partition portion 81, which is the wide portion.

[0053] As shown in FIG. 5B , a notch 71 is provided at one end in the longitudinal direction of the wide portion. The notch 71 is a missing portion provided outward on one side in the winding axis direction. Specifically, the notch 71 is provided on one of both sides in the winding axis direction, on the side where one end of the second coil 12 wound in the lower layer of the peripheral tape 70 is located (the upper side in the drawing). In this embodiment, the notch 71 has a rectangular shape obtained by cutting out a corner of one end in the longitudinal direction of the peripheral tape 70. In this case, the length of the notch 71 in the winding axis direction is preferably equal to or greater than the sum of the width of the second surface tape 62 and the diameter of the second coil 12. Furthermore, the length of the notch 71 in the winding axis direction is preferably equal to or less than half the width of the wide portion. The length of the notch 71 in the longitudinal direction is preferably equal to or greater than the diameter of the second coil 12.

[0054] The notch 71 is not limited to being provided at a corner of the wide portion as illustrated in this embodiment. For example, the notch 71 may be formed in a shape recessed inward in the longitudinal direction on one end of the peripheral tape 70 in the longitudinal direction (the side extending in the winding axis direction). In this case, the notch 71 is formed inward in the winding axis direction from one end of the peripheral tape 70 in the longitudinal direction. Preferably, the notch 71 is formed inward in the winding axis direction from a portion of the peripheral tape 70 that contacts the second creeping tape 62. In this case, the depth (circumferential length) and width (winding axis length) of the notch 71 are preferably equal to or greater than the diameter of the second coil 12. Another example of the shape of the notch 71 is a shape in which a side extending in the longitudinal direction of the peripheral tape 70 at one end of the peripheral tape 70 is recessed inward in the width direction. The notch 71 is formed inward in the longitudinal direction from one end of the side. In this case, the depth of the notch 71 (the length in the winding axis direction) is preferably equal to or greater than the sum of the width of the second surface creeping tape 62 and the diameter of the second coil 12. In addition, the width of the notch 71 (the length in the longitudinal direction) is preferably equal to or greater than the diameter of the second coil 12.

[0055] The second coil 12 is disposed across the inside (lower layer side) and outside (upper layer side) of the second insulating tape (peripheral tape 70) through the cutout 71. That is, as shown in Fig. 2, a part of the second coil 12 (such as the second winding portion 12b) is disposed below the peripheral tape 70 (wide portion), and another part of the second coil 12 (such as the second return portion 12f) is disposed above the peripheral tape 70 (wide portion). Also, as shown in Fig. 5(c), the boundary portion 12g between the second winding portion 12b and the second return portion 12f is disposed within the cutout 71 when viewed from the radial direction.

[0056] The outer peripheral tape 70 having the notch 71 is wound in the following manner. When the second coil 12 is wound from the right side (lower side of the drawing) to the left side (upper side of the drawing), the outer peripheral tape 70 is positioned between the flanges 32 on both sides so that the notch 71 is positioned on the left side as shown in FIG. 5B . Furthermore, the outer peripheral tape 70 is positioned so that the portion where the second coil 12 is folded back (the boundary 12g (see FIG. 5C )) is positioned within the notch 71 when viewed in the radial direction. Specifically, the outer peripheral tape 70 is positioned so that the terminal 33 (e.g., terminal 337) around which one end of the winding end of the second coil 12 is wound partially overlaps with the notch 71 when viewed in the winding axis direction. After the outer peripheral tape 70 is positioned, the second coil 12, which is positioned within the notch 71 when viewed in the radial direction, is folded toward the terminal 337 at the boundary 12g. The second coil 12 (second return portion 12f) is disposed along the outside of the outer peripheral tape 70 up to the right flange 32c. The second coil 12 is then pulled out radially outward along the inner surface 32a of the flange 32c as described above, and then wound around the terminal 337. The outer peripheral tape 70 is wound around the second coil 12, including the second return portion 12f.

[0057] The outer tape 70 is wound on the upper side of the second winding portion 12b. By fixing a partial length region of the winding end of the second winding portion 12b with the outer tape 70, it becomes easy to fold the second coil 12 at the boundary portion 12g and pass it over to the terminal 337. Furthermore, by arranging the second winding portion 12b on the lower side of the outer tape 70 and the second return portion 12f on the upper side of the outer tape 70, loosening of the partial length region of the winding end of the second winding portion 12b and the second return portion 12f is prevented.

[0058] In this embodiment, the second insulating tape is the outer peripheral tape 70, but the second insulating tape is not limited to the outer peripheral tape 70. For example, when the second coil 12 is wound in two or more layers as in the fifth embodiment, the second insulating tape is a partition tape 80 wound between the first and second layers of the second coil 12. Furthermore, when the third coil 13 is wound on the upper side of the first layer of the second coil 12, the second insulating tape is a second interlayer tape 52, which will be described later.

[0059] Second Embodiment This embodiment differs from the first embodiment in that the first creepage tape 61 also constitutes the integrated insulating tape 40 together with the interlayer tape 50. Similar to the transformer 100 of the first embodiment, the transformer 100 of this embodiment includes a bobbin 30, a first coil 11, a second coil 12, an interlayer tape 50, and a creepage tape 60. The first coil 11 is wound in a lower layer of the multiple coils 10 wound in layers around the bobbin 30. The second coil 12 is wound in an upper layer of the first coil 11. The interlayer tape 50 is wound between the first coil 11 and the second coil 12. The creepage tape 60 is wound outward of the first coil 11 or the second coil 12 in the winding axis direction. At least a portion of the creepage tape 60 and the interlayer tape 50 form an insulating tape (integrated insulating tape 40) that is a single component. Specifically, the surface creeping tape 60 (second surface creeping tape 62) wound around the outside of the second coil 12 in the winding axis direction and the interlayer tape 50 form a single insulating tape (integrated insulating tape 40). Furthermore, the surface creeping tape 60 (second surface creeping tape 62) wound around the outside of the first coil 11 in the winding axis direction and the interlayer tape 50 form a single insulating tape (integrated insulating tape 40). That is, as shown in FIG. 8( a ), the integrated insulating tape 40 has a hollow interior in the winding axis direction at both longitudinal ends. In this embodiment, the first surface creeping tape 61 is disposed on both outer sides of the first coil 11 in the winding axis direction, and the second surface creeping tape 62 is disposed on both outer sides of the second coil 12 in the winding axis direction. However, this is not limited to this. The surface creeping tape 60 may be disposed only on the outside of one side of the first coil 11 or the second coil 12 in the winding axis direction. The widths of the first surface creeping tape 61 and the second surface creeping tape 62 may be equal, or one may be larger and the other smaller. Furthermore, the length in the longitudinal direction of the first surface-creeping tape 61 and the length in the longitudinal direction of the second surface-creeping tape 62 may be equal to each other, or one may be larger and the other may be smaller.

[0060] By configuring the integrated insulating tape 40 as described above, the first surface-creeping tape 61, the interlayer tape 50, and the second surface-creeping tape 62 can be wound continuously in the insulating tape winding step described below, which allows the number of manufacturing steps to be reduced.

[0061] 6(b), in this embodiment, the transformer 100 has a second insulating tape (peripheral tape 70) wound around the upper layer side of a portion of the second coil 12 and including a wide portion having a width equal to or greater than the length of the winding axis direction of the winding shaft portion 31 of the bobbin 30. A notch 71 (see FIG. 5(b)) is provided at one end in the longitudinal direction of the wide portion, and the second coil 12 is disposed on both the lower layer side and the upper layer side of the peripheral tape 70 through the notch 71.

[0062] In this embodiment, as shown in Figure 6 (b), a portion of the second coil 12 (second starting portion 12e) is arranged between the interlayer tape 50 and a surface creeping tape (second surface creeping tape 62b) formed from a single member together with the interlayer tape 50 and wound outward in the winding axis direction of the second coil 12.

[0063] The transformer 100 of this embodiment is manufactured as follows. Similar to the first embodiment, the manufacturing method of the transformer 100 of this embodiment includes a first coil winding step of winding the first coil 11 around the winding shaft portion 31, an insulating tape winding step of continuously winding a part of the interlayer tape portion 41 and the surface tape portion 42 around the bobbin 30, and a second coil winding step of winding the second coil 12 around the outside of the interlayer tape portion 41.

[0064] First, as shown in FIG. 7A , one end of the first coil 11 is wound around the base of the terminal 332. The first coil 11 is pulled into the winding shaft 31 along the inner surface 32a of the flange 32b. Specifically, the first coil 11 is pulled inward in the winding shaft direction by at least the width (length in the winding shaft direction) of a jig 200, which will be described later. A wire supply unit located at the tip of the first coil 11 is not shown. Next, as shown in FIG. 7B , the jig 200 is placed on the outer side of the winding shaft 31 in the winding shaft direction. In this embodiment, the jigs 200 are placed on both outer sides of the winding shaft 31 in the winding shaft direction. When the flange 32 and the first coil 11 are to be separated only on one outer side of the winding shaft 31 in the winding shaft direction, as in a third embodiment described later, the jig 200 may be placed on the side where the flange 32 and the first coil 11 are to be separated. The jig 200 is also placed on the upper layer side of the first starting portion 11e.

[0065] The jig 200 is a tool for defining an area of ​​the winding shaft 31 where the first coil 11 is wound. The jig 200 is detachably attached to the winding shaft 31 and holds the first drawn-out portion 11a of the first coil 11. The length of the first coil 11 held by the jig 200 becomes the first start portion 11e (see FIG. 6B ), and the portion of the first coil 11 that is inward of the jig 200 in the winding axis direction becomes the first wound portion 11b. In other words, the jig 200 separates the first coil 11 from one end of the winding shaft 31 in the winding axis direction. Specifically, the jig 200 separates the first coil 11 from the flange portion 32. The width of the jig 200 is preferably equal to or greater than the width of the first surface tape 61. In this embodiment, the jig 200 has a shape and dimensions that allow it to be disposed around substantially the entire length of the winding shaft 31, but is not limited to this. For example, jigs 200 may be arranged discretely around part of the periphery of winding shaft unit 31, separating first coil 11 from one end of winding shaft unit 31 in the winding axis direction. Jig 200 is made of a material such as metal or resin that has sufficient rigidity to separate first coil 11 from one end of winding shaft unit 31 in the winding axis direction. Examples of jig 200 include a clamp structure in which winding shaft unit 31 is sandwiched between two arc-shaped metal members, and a tape-shaped member that is wound around winding shaft unit 31.

[0066] Once the jig 200 is in place, the first coil winding step is performed. The first coil 11 is wound around the jig in the winding axis direction as shown in FIG. 7( b). Once the first coil 11 is wound, the jig 200 is removed.

[0067] After the first coil 11 is wound, the insulating tape winding process is performed. After the jig 200 is removed, the integrated insulating tape 40 is wound around the bobbin 30 as shown in FIG. 8( a). The integrated insulating tape 40 is wound in the order of the surface creepage tape portion 42a (first surface creepage tape 61), the interlayer tape portion 41 (interlayer tape 50), and the surface creepage tape portion 42b (second surface creepage tape 62). The first surface creepage tape 61 is wound around the region of the winding shaft 31 where the jig 200 was located. In other words, the first surface creepage tape 61 is wound outward of the first coil 11 in the winding axis direction.

[0068] In this embodiment, as shown in FIG. 8( a), one end of the first coil 11 is positioned radially outward of the winding shaft portion 31 until at least a portion of the first surface creeping tape 61 is wound. To avoid interference between the first surface creeping tape 61 and a wire supply portion for winding the first coil 11, the wire supply portion is preferably positioned radially outward of the first winding portion 11b. After at least a portion of the first surface creeping tape 61 is wound, the first coil 11 wound on the rightmost side (lower side of the drawing) of the first winding portion 11b is bent to the left (upper side of the drawing) as shown in FIG. 8( b). The first coil 11 is positioned along the inner surface 32a of the flange portion 32b, pulled out radially outward, and wound around the base of the terminal 333. After one end of the first coil 11 is wound around the terminal 333, the remaining portion of the first surface creeping tape 61, the interlayer tape 50, and the second surface creeping tape 62 are wound continuously in this order. By winding the first coil 11 and the integrated insulating tape 40 as described above, in this embodiment, the first starting portion 11e is positioned between the winding shaft portion 31 and the first surface tape 61a, as shown in Figure 6 (b).

[0069] The winding start positions of the first surface creeping tapes 61a and 61b may be determined taking into consideration the winding position of the interlayer tape portion 41. For example, the winding start positions of the first surface creeping tapes 61a and 61b need to be aligned with each other in the circumferential direction. Specifically, the winding start position of the first surface creeping tape 61a or 61b is a position that is circumferentially separated from the planned winding position of the interlayer tape portion 41 by the length of the first surface creeping tape 61a or 61b. The winding start positions of the first surface creeping tape 61a and 61b also need to be aligned in the winding axis direction. Specifically, the distance between the winding start position of the first surface creeping tape 61a and the winding start position of the first surface creeping tape 61b may be set in the winding axis direction to match the width of the interlayer tape portion 41. By aligning the winding start positions of the first surface creeping tape 61a and the first surface creeping tape 61b in the circumferential direction and the winding axis direction in this manner, the interlayer tape portion 41 can be wound without wrinkles.

[0070] As in the first embodiment, after the integrated insulating tape 40 is wound, a second coil winding step is performed in which the second coil 12 is wound on the upper layer side of the interlayer tape 50. Furthermore, after the second coil 12 is wound, an outer tape 70 having a notch 71 is wound around the winding shaft portion 31 as the second insulating tape.

[0071] Third Embodiment This embodiment differs from the second embodiment in that the first surface creeping tape 61 and the second surface creeping tape 62 are arranged only on the outside of one side of the coil 10 in the winding axis direction.

[0072] Similar to the transformer 100 of the first embodiment, the transformer 100 of this embodiment includes a bobbin 30, a first coil 11, a second coil 12, an interlayer tape 50, and a surface creepage tape 60. As shown in Fig. 9(a) , both ends of the first coil 11 are extended to one side (left side, upper side of the drawing) in the winding axis direction, and both ends of the second coil 12 are extended to the other side (right side, lower side of the drawing) in the winding axis direction. Furthermore, as shown in Fig. 10(a) and Fig. 10(b) , a surface creepage tape 60 is wound around at least the other side (right side) of the first coil 11 and at least one side (left side) of the second coil 12.

[0073] By arranging the surface creeping tape 60 only on the outside of one side of the coil 10 in the winding axis direction as in this embodiment, a wider area of ​​the winding shaft portion 31 for winding the coil 10 can be secured than when the surface creeping tapes 60 are arranged on both outsides of the coil 10 in the winding axis direction. Furthermore, when the first surface creeping tapes 61 are arranged on both outsides of the first coil 11 in the winding axis direction, as described above, it is necessary to align the winding start positions between the pair of first surface creeping tapes 61, 61 in the circumferential direction and in the winding axis direction. By winding the first surface creeping tape 61 only on the outside of one side of the first coil 11 in the winding axis direction as in this embodiment, this alignment work can be omitted. This increases the winding efficiency of the integrated insulating tape 40.

[0074] In this embodiment, the second creeping tape 62 wound outward in the winding axis direction of the second coil 12 and the interlayer tape 50 form a single-piece integrated insulating tape 40, and the first creeping tape 61 wound outward in the winding axis direction of the first coil 11 and the interlayer tape 50 form a single-piece integrated insulating tape 40. More specifically, the creeping tape 60 (first creeping tape 61) wound on the other side (right side) of the first coil 11, the creeping tape 60 (second creeping tape 62) wound on one side (left side) of the second coil 12, and the interlayer tape 50 form a single-piece insulating tape (integrated insulating tape 40). That is, in this embodiment, as shown in FIG. 9( b ), the integrated insulating tape 40 has a rectangular interlayer tape portion 41, and creeping tape portions 42 (creeping tape portion 42 a and creeping tape portion 42 b) are provided at diagonal positions of the interlayer tape portion 41, extending in the longitudinal direction.

[0075] In this embodiment, the first surface creeping tape 61 is wound only on the other side (right side) of the first coil 11, and the second surface creeping tape 62 is wound only on one side (left side) of the second coil 12. Instead of this embodiment, as shown in the first and second embodiments, the tapes may be wound on both one side and the other side of the coil 10 (both sides in the winding axis direction). Instead of this embodiment, the first surface creeping tape 61 and the interlayer tape 50 may be separate members, or the second surface creeping tape 62 and the interlayer tape 50 may be separate members. In other words, only the second surface creeping tape 62 and the interlayer tape 50, or only the first surface creeping tapes 61 and 50, may be a single member.

[0076] Since the first surface creeping tape 61, the interlayer tape 50, and the second surface creeping tape 62 are one component, these tapes can be wound in one step in the manufacturing method of the transformer 100 described below.

[0077] 10A, in this embodiment, the transformer 100 has a second insulating tape (peripheral tape 70) wound around the upper layer side of a portion of the second coil 12 and including a wide portion having a width equal to or greater than the length of the winding axis direction of the winding shaft portion 31 of the bobbin 30. A notch 71 is provided at one end in the longitudinal direction of the wide portion, and the second coil 12 is disposed on both the lower layer side and the upper layer side of the peripheral tape 70 through the notch 71.

[0078] The manufacturing process for the transformer 100 of this embodiment includes a first coil winding process, an insulating tape winding process, and a second coil winding process, similar to the first and second embodiments. Specifically, the transformer 100 is manufactured as follows. First, a jig 200 (see FIG. 7B ) is placed on the outer side of the winding axis of the winding shaft 31. In this embodiment, the jig 200 is placed only on the other side (right side) of the winding shaft 31. This is because, in this embodiment, it is necessary to separate the other side of the first coil 11 from the flange 32c. Once the jig 200 is placed, the first coil winding process is performed. The first coil 11 is wound around an area of ​​the winding shaft 31 where the jig 200 is not placed. As shown in FIG. 9B , both ends of the first coil 11 are tied around the bases of the terminals 33 (terminals 332 and 333 in this embodiment) on one side (left side). Once the first coil 11 is wound, the insulating tape winding process is performed. First, the surface creeping tape portion 42a (first surface creeping tape 61) of the integrated insulating tape 40 is wound between the first coil 11 and the flange 32c. Next, the interlayer tape portion 41 is wound on top of the first coil 11, and then the surface creeping tape portion 42b (second surface creeping tape 62) is wound on the left side of the winding shaft portion 31. After the second surface creeping tape 62 is wound, a second coil winding process is performed, in which the second coil 12 is wound on top of the interlayer tape portion 41. The second coil 12 is wound in an area inside the pair of flanges 32, excluding the area where the second surface creeping tape 62 is wound. In this embodiment, the second coil 12 is wound between the flange 32c and the second surface creeping tape 62. As in the first embodiment, an outer peripheral tape 70 is wound around the outer periphery of the second coil 12 as a second insulating tape.

[0079] <Fourth embodiment> This embodiment differs from the first embodiment in that the terminal 33 is provided on only one side of the bobbin 30 in the winding axis direction, and the first coil 11 and the second coil 12 are pulled out to the same side (the side in the winding axis direction where the terminal 33 is located).

[0080] Similar to the transformer 100 of the first embodiment, the transformer 100 of this embodiment also includes a bobbin 30 extending in the winding axis direction, a first coil 11 wound in a lower layer, a second coil 12 wound in an upper layer above the first coil 11, an interlayer tape 50 wound between the first coil 11 and the second coil 12, and one or more creeping tapes 60. In this embodiment, the second creeping tape 62 wound around the second coil 12 on the outer side in the winding axis direction and the interlayer tape 50 form an integrated insulating tape 40 as a single member, and the first creeping tape 61 wound around the first coil 11 on the outer side in the winding axis direction and the interlayer tape 50 are separate members.

[0081] The bobbin 30 has a plurality of terminals 33 on one side in the winding axis direction. In this embodiment, as shown in FIG. 11( a), the bobbin 30 has four terminals 33 (terminals 331 to 334) on the left side. As shown in FIG. 11( b), the terminals 33 have a surface (vertical surface 33 b) perpendicular to the winding axis direction. The transformer 100 is placed on the mounting substrate so that the vertical surface 33 b is grounded to the mounting substrate. In other words, the transformer 100 in this embodiment is a vertical transformer placed so that the winding axis portion is perpendicular to the mounting substrate. The terminals 33 are not limited to a terminal shape for planar mounting and may be pin-shaped.

[0082] In this embodiment, as shown in FIG. 11( a), both ends of the first coil 11 (first lead-out portion 11 a) and both ends of the second coil 12 (second lead-out portion 12 a) are drawn out to one side in the winding axis direction (upper side of the paper). In this embodiment, the "one side" refers to the side in the winding axis direction where the terminal 33 is located, and is referred to as the left side of the transformer 100 in this embodiment. The left side of the transformer 100 in this embodiment corresponds to the left side of the paper in FIG. 11( b). The first lead-out portion 11 a and the second lead-out portion 12 a, which are drawn out to the same side in the winding axis direction, maintain a creepage distance of at least a specified value between them in the circumferential direction of the winding shaft portion 31. A creepage tape 60 is wound around one side (left side) of the first coil 11 and the second coil 12 and the other side (right side) of the first coil 11 or the second coil 12. In this embodiment, the creepage tape 60 is wound around both sides of the first coil 11 and the second coil 12 in the winding axis direction, but this is not limited thereto. The first surface creeping tape 61 may not be arranged on the other side (right side) of the first coil 11, and the first surface creeping tape 61 may be arranged only on one side (left side). Also, the second surface creeping tape 62 may not be arranged on the other side (right side) of the second coil 12, and the second surface creeping tape 62 may be arranged only on one side (left side). However, if the first surface creeping tape 61b is not arranged on the other side of the first coil 11, the second surface creeping tape 62b is wound around the other side of the second coil 12. Similarly, if the second surface creeping tape 62b is not wound around the other side of the second coil 12, the first surface creeping tape 61b is wound around the other side of the first coil 11. In other words, the surface creeping tape 60 is wound around at least one of the other side of the first coil 11 and the other side of the second coil 12.

[0083] In this embodiment, the first creeping tape 61 and the interlayer tape 50 are separate members, and the interlayer tape 50 and the second creeping tape 62 form a single, integrated insulating tape 40. However, this is not limited to this. For example, instead of this embodiment, the first creeping tape 61, the interlayer tape 50, and the second creeping tape 62 may all be a single member to form the integrated insulating tape 40, as in the second embodiment. Alternatively, the first creeping tape 61 and the interlayer tape 50 may form a single, integrated insulating tape 40, and the interlayer tape 50 and the second creeping tape 62 may be separate members.

[0084] When the first coil 11 and the second coil 12 are pulled out on the same side in the winding axis direction as in this embodiment, the width of the surface creeping tape 60 can be set as follows. That is, the total length in the winding axis direction of the surface creeping tape 60 arranged on the other side (right side) of the first coil 11 or the second coil 12 is equivalent to the length in the winding axis direction of each of the surface creeping tapes 60 arranged on one side (left side) of the first coil 11 or the second coil 12. That is, the total width of the first surface creeping tape 61b and the second surface creeping tape 62b is equivalent to the respective widths of the first surface creeping tape 61a and the second surface creeping tape 62a. Here, "equivalent" means that the total width of the first surface creeping tape 61b and the second surface creeping tape 62b is more than half the width of the first surface creeping tape 61a or the second surface creeping tape 62a and is not more than twice the width of the first surface creeping tape 61a or the second surface creeping tape 62a. When the surface creeping tape 60 is not wound around the other side (right side) of the first coil 11 but is wound only around the other side (right side) of the second coil 12, the sum of the widths of the first surface creeping tape 61b and the second surface creeping tape 62b is the width of the second surface creeping tape 62b. Similarly, when the surface creeping tape 60 is not wound around the other side of the second coil 12 but is wound only around the other side of the first coil 11, the sum of the widths of the first surface creeping tape 61b and the second surface creeping tape 62b is the width of the first surface creeping tape 61b.

[0085] In this embodiment, as shown in FIG. 11B , the coils 10 are not only adjacent between the lead-out portion of one coil 10 and the winding portion of the other coil 10 as in the first embodiment, but also adjacent between the ends (right ends) of the winding portions of the coils 10 on the other side. Specifically, the first coil 11 and the second coil 12 are also adjacent between the right end 11d of the first winding portion 11b and the right end 12d of the second winding portion 12b. The creeping distance between the right end 11d of the first winding portion 11b and the right end 12d of the second winding portion 12b is at least the sum of the widths of the first creeping tape 61b, the second creeping tape 62b, and the winding thickness of the interlayer tape 50. In other words, to maintain a sufficient creeping distance between the right end 11d of the first coil 11 and the right end 12d of the second coil 12, it is sufficient that the sum of the widths of the first creeping tape 61b and the second creeping tape 62b be equal to or greater than a specified value.

[0086] In this embodiment, the width of the first surface creeping tape 61b is equal to the width of the second surface creeping tape 62b, but this is not limited to this. The width of the first surface creeping tape 61b may be longer or shorter than the width of the second surface creeping tape 62b. The embodiment in which the width of the first surface creeping tape 61b is longer or shorter than the width of the second surface creeping tape 62b also includes an embodiment in which one of the first surface creeping tape 61b and the second surface creeping tape 62b is not disposed, as described above. For example, the width of the surface creeping tape 60 wound on the other side (right side) of the coil 10 having the longer winding width of the first coil 11 or the second coil 12 may be shorter than the width of the surface creeping tape 60 wound on the other side (right side) of the coil 10 having the shorter winding width. The winding width refers to the length of the region of the winding shaft portion 31 in the winding axis direction required for winding the coil 10. Specifically, the winding width is the winding pitch of the coil 10 multiplied by the number of winding turns. When the coil 10 is densely wound, the winding pitch of the coil 10 is equal to the wire diameter of the coil wire. By arranging a surface creeping tape 60 with a short width in the same layer as the coil 10 that requires a long winding width, or by not arranging a surface creeping tape 60, the overall dimension of the bobbin 30 in the winding axis direction can be reduced. In other words, when the dimension of the bobbin 30 in the winding axis direction is predetermined, a large length region for winding the coil 10 can be secured in the winding axis direction.

[0087] As shown in FIG. 11B , the transformer 100 includes a second insulating tape (peripheral tape 70) wound over a portion of the second coil 12 and including a wide portion having a width equal to or greater than the length of the winding axis of the winding shaft portion 31 of the bobbin 30. A notch 71 (see FIG. 5B ) is provided at one longitudinal end of the wide portion, and the second coil 12 is disposed across the lower and upper layers of the peripheral tape 70 through the notch 71. However, while the notch 71 illustrated in FIG. 5B in the first embodiment is provided on the left side (upper side in the figure) of one end of the peripheral tape 70, the notch 71 in this embodiment is provided on the right side (lower side in the figure) of one end of the peripheral tape 70. In this embodiment, one end of the winding end of the second coil 12 wound on the lower side of the peripheral tape 70 is located on the right side, and the position of the notch 71 corresponds to the winding end position.

[0088] A part of the second coil 12 (second start portion 12e (see FIG. 4(d) , not shown in FIG. 11(b) )) is disposed between the interlayer tape 50 and the surface creeping tape 60 (second surface creeping tape 62) which is formed of a single member together with the interlayer tape 50 and wound outward in the winding axis direction of the second coil 12. However, while the second start portion 12e illustrated in FIG. 4(d) in the first embodiment is disposed between the interlayer tape 50 and the second surface creeping tape 62b on the right side, the second start portion in this embodiment is disposed between the interlayer tape 50 and the second surface creeping tape 62a on the left side. This is because, in this embodiment, the second coil 12 is wound around the terminal 331 provided on the left flange 32b, is pulled into the winding shaft portion 31 from the left side along the inner surface 32a of the flange 32b, and is routed along the upper surface of the interlayer tape 50 to form the second winding portion 12b.

[0089] The manufacturing method of the transformer 100 in this embodiment includes a first coil winding step, an insulating tape winding step, and a second coil winding step, similar to the first and second embodiments. Specifically, the transformer 100 is manufactured as follows. First, the first creeping tape 61 is wound around the winding shaft portion 31, near the outer side in the winding axis direction. After the first creeping tape 61 is wound, the first coil winding step is performed. The first coil 11 is wound around the inner side in the winding axis direction of the first creeping tape 61. As shown in FIG. 11( a ), both ends of the first coil 11 are intertwined with the terminals 33 (terminals 332 and 333 in this embodiment) on one side (the left side). After the first coil 11 is wound, the insulating tape winding step is performed. Of the integrated insulating tape 40, the interlayer tape 50 is wound around the first coil 11, and then the second creeping tape 62 is wound. After the second surface creeping tape 62 is wound, a second coil winding step is performed, in which the second coil 12 is wound on the upper layer of the interlayer tape 50. The second coil 12 is wound inside the second surface creeping tape 62 in the winding axis direction. Both ends of the second coil 12 are wound around one (left) terminal 33 (terminals 331 and 334 in this embodiment). As in the first embodiment, an outer periphery tape 70 is wound around the outer periphery of the second coil 12 as a second insulating tape.

[0090] Fifth Embodiment A transformer 100 according to a fifth embodiment will be described using FIGS. 12( a) to 12(c), 13(a) to 13(c), 14(a) to 14(d), 15, and 16. This embodiment differs from the first embodiment in that the transformer 100 includes a third coil 13 and that the second coil 12 and the third coil 13 are wound in two layers. Like the transformer 100 of the first embodiment, the transformer 100 of this embodiment includes a bobbin 30, a first coil 11, a second coil 12, an interlayer tape 50, and a surface-creeping tape 60. The transformer 100 further includes a third coil 13, a partition tape 80, and a second interlayer tape (second interlayer tape 52). As shown in FIGS. 15 and 16, the third coil 13 is wound in layers above the second coil 12. Surface-creeping tape 60 (third surface-creeping tape 63) is wound around both outer sides of the third coil 13 in the winding axis direction. The partition tape 80 is wound between the layers of the coil 10, which is wound in multiple layers. Specifically, in the second coil 12 and the third coil 13, which are wound in two layers, the partition tape 80 is wound between the first and second layers.

[0091] Similar to the interlayer tape 50 being wound between the first coil 11 and the second coil 12, a second interlayer tape 52 is wound between the second coil 12 and the third coil 13. In this embodiment, the second interlayer tape 52 and the third creepage tape 63 form a second integrated insulating tape (second tape 90) of one component. Also, in this embodiment, as in the first embodiment, the first creepage tape 61 and the interlayer tape 50 are separate components, and the interlayer tape 50 and the second creepage tape 62 form a single integrated insulating tape 40 (first tape 40). Alternatively, the first creepage tape 61 and the interlayer tape 50 may form the first tape 40, or the second creepage tape 62 and the second interlayer tape 52 may form the second tape 90. Furthermore, the first surface-creeping tape 61, the interlayer tape 50, and the second surface-creeping tape 62 may form the first tape 40 as a single component, or the second surface-creeping tape 62, the second interlayer tape 52, and the third surface-creeping tape 63 may form the second tape 90 as a single component.

[0092] In this embodiment, as shown in Figure 15, a portion of the second coil 12 (second starting portion 12e) is arranged between the interlayer tape 50 and a surface creeping tape (second surface creeping tape 62b) formed from a single member together with the interlayer tape 50 and wound outward in the winding axis direction of the second coil 12.

[0093] The manufacturing method of the transformer 100 of this embodiment includes a first coil winding step, an insulating tape winding step, and a second coil winding step, as in the first embodiment, and further includes a second insulating tape winding step of winding a second tape 90 and a third coil winding step of winding a third coil 13, which will be described later. Specifically, the transformer is manufactured as follows.

[0094] As with the transformer 100 of the first embodiment, a first coil winding process is performed after winding the first surface tape 61. After the first coil 11 is wound, an insulating tape winding process is performed in which the first tape 40 is wound. In this embodiment, as with the first embodiment, the interlayer tape 50 (interlayer tape portion 41) of the first tape 40 is wound first, and then the second surface tape 62 is wound subsequently.

[0095] After the first tape 40 is wound, a second coil winding process is performed in which the second coil 12 is wound. In this embodiment, the second coil 12 is wound in two layers around the bobbin 30. As in the transformer 100 of the first embodiment, the second coil 12 is wound around the base of the right terminal 336, and the first layer of the second coil 12 is then wound from right to left. The first layer of the second coil 12 is wound inside the second surface tape 62 in the winding axis direction. After the first layer of the second coil 12 is wound, as shown in FIG. 12( a), a partition tape 80 (partition tape 80a) described below as a second insulating tape is wound on top of the first layer of the second coil 12. The partition tape 80 has a partition portion 81 (a wide portion of the second insulating tape) and a surface tape portion 83, as described below. As shown in FIG. 12( c), the second layer of the second coil 12 is wound from left to right (top to bottom in the figure) inside the surface tape portion 83 in the winding axis direction. One end of the second coil 12 is wound around the right terminal 337 .

[0096] The partition tape 80 is an insulating tape wound between different layers of the coil 10 when the coil 10 is wound in multiple layers. The partition tape 80 is wound on top of a portion of the coil 10 (e.g., the first layer of the second coil 12) and includes a partition section 81 having a width equal to or greater than the length of the winding axis of the winding shaft section 31 of the bobbin 30. The partition section 81 is the portion of the partition tape 80 that is wound between different layers of the coil 10. The width of the partition section 81 refers to the longest length of the partition section 81 in the winding axis direction. The partition section 81 also includes a portion in which a notch 82, described below, is formed. The length of the partition section 81 in its longitudinal direction (circumferential direction of the winding shaft section 31) is preferably long enough to wrap around the outer periphery of the coil 10 wound in the layer below the partition section 81. Specifically, the length of the partition section 81 in its longitudinal direction is equal to or greater than the outer periphery of the coil 10 wound in the lower layer. As described above, the partition tape 80 in this embodiment has a surface-creeping tape portion 83 at one end of the partition portion 81. That is, as shown in FIG. 12( a), one end of the partition tape 80 in the longitudinal direction is hollow. The surface-creeping tape portion 83 is wound as the second surface-creeping tape 62c in the same layer as the second coil 12 in the second layer. Alternatively, the partition portion 81 and the second surface-creeping tape 62c may be separate members. In that case, the member including the partition portion 81 is the partition tape 80.

[0097] Similar to the peripheral tape 70 in the first embodiment, a notch 82 is provided at one longitudinal end of the partition 81. Similar to the notch 71 provided in the peripheral tape 70 in the first embodiment, the notch 82 may be formed by cutting out a corner of the partition 81 in a rectangular shape or by forming a concave edge of the partition 81. The notch 82 in this embodiment is a rectangular cutout portion of one outer side of the partition 81 in the width direction at one longitudinal end of the partition 81. The length of the notch 82 in the winding axis direction is equal to or greater than the sum of the width of the second surface tape 62c, which is integral with the partition tape 80, and the diameter of the second coil 12. The length of the notch 82 in the longitudinal direction is preferably equal to or greater than the diameter of the second coil 12.

[0098] The second coil 12 is disposed across the lower and upper layers of the partition tape 80 (partition portion 81) in the radial direction through the cutout 82. Specifically, as shown in FIG. 12( b), a partial length region (boundary portion 12g) of the second coil 12 connecting the first and second layers is disposed within the cutout 82 when viewed in the radial direction. The dimension in the tape length direction from one end of the partition portion 81 where the cutout 82 is not provided to the cutout 82 (indicated by a double-sided arrow in FIG. 12( a)) is preferably shorter than the length required for one full turn of the coil 10 wound in the lower layer of the partition portion 81 around the outer circumferential surface of the partition portion 81. This allows a gap to be provided for the coil 10 (second coil 12) to cross from the first layer to the second layer, as shown in FIG. 12( b). By providing this gap, the coil 10 can cross between the lower and upper layers of the partition portion 81 through the cutout 82.

[0099] As described above, the notch 82 is provided at one end of the partition portion 81, near the outside on one side in the winding axis direction. Specifically, the notch 82 is provided on the side (left side) where one end of the coil 10 wound inside the partition portion 81 is located. As shown in FIG. 12( c), another part of the second coil 12 (such as the second coil 12 wound in the second layer) that is passed through the notch 82 and placed in the upper layer of the partition tape 80 (partition portion 81) is wound from one side to the other side in the winding axis direction (from top to bottom on the page). When winding the coil 10 in multiple layers, winding the partition tape 80 between the lower and upper layers allows the coil 10 in the upper layer to be stably wound over the coil 10 in the lower layer without being affected by any looseness in the lower layer.

[0100] When the second coil 12 is wound, the second tape 90 (see FIG. 13( a) ) is wound. Like the integrated insulating tape 40, the second tape 90 has an interlayer tape portion 91 (second interlayer tape 52) and a surface creepage tape portion 92 (third surface creepage tape 63). As shown in FIG. 13( a) , a portion of the interlayer tape portion 91 of the second tape 90 is wound around the bobbin 30. When a portion of the interlayer tape portion 91 is wound around the bobbin 30, the third coil 13, one end of which is wound around the terminal 335, is pulled inward in the winding axis direction onto the interlayer tape portion 91. As shown in FIG. 13( b) , the second tape 90 is wound so that the surface creepage tape portion 92 (the third surface creepage tape 63 on the lower side of the drawing) is located above the start portion (third start portion 13 a) of the third coil 13 that has been pulled inward in the winding axis direction. In other words, the third start portion 13 a is located between the second interlayer tape 52 and the third surface creepage tape 63. The interlayer tape portion 91 and the surface tape portion 92 of the second tape 90 are wound continuously around the bobbin 30 .

[0101] In this embodiment, the third coil 13 is wound around the bobbin 30 in two layers. The first layer of the third coil 13 is wound from right to left in the region inside the third creeping tape 63 in the winding axis direction, as shown in FIG. 13( c). After the first layer of the third coil 13 is wound, the partition tape 80b is wound on top of the first layer of the third coil 13, as shown in FIGS. 14( a) and 14(b). The third coil 13 is pulled out to the upper layer side of the partition portion 81 through a notch 82 provided in the partition portion 81 of the partition tape 80b, and a portion of the third coil 13 is disposed on the upper layer of the partition portion 81. The third coil 13 pulled out through the notch 82 is wound around the bobbin 30 from left to right (from top to bottom on the page), as shown in FIG. 14( c). Specifically, the third coil 13 is wound in the region inside the third creeping tape 63 in the winding axis direction. One end of the third coil 13 wound to the right side is wound around the terminal 338 .

[0102] 14(d), the outer tape 70 is wound at least once around the upper layer of the third coil 13. The outer tape 70 in this embodiment does not have the notch 71 in the first embodiment. In this embodiment, the creepage distance between the second lead-out portion 12a and the lead-out portion of the third coil 13 (third lead-out portion 13b) is also maintained at a specified value or more.

[0103] The present invention is not limited to the above-described embodiment, but includes various modifications and improvements as long as the object of the present invention is achieved.

[0104] In the above-described embodiment, the first winding portion 11b and the flange 32 are separated by the first surface creeping tape 61 or the jig 200, but this is not limited thereto. For example, instead of the above-described embodiment, a sub-flange or a protrusion may be provided midway along the length of the winding shaft portion 31 in the winding axis direction. Specifically, the sub-flange or the protrusion is provided inward of the flange 32 in the winding axis direction by the distance by which the first winding portion 11b and the flange 32 are to be separated. The sub-flange or the protrusion may prevent the first winding portion 11b from loosening further outward in the winding axis direction than the sub-flange, thereby maintaining the distance between the flange 32 and the first winding portion 11b. In this case, the first surface creeping tape 61 need not be wound.

[0105] In addition, in the present embodiment, both ends of the coil 10 are pulled out radially outward from the winding portion to the side end faces of the flange 32, but this is not limited to this. A groove recessed from the periphery of the flange 32 toward the axis may be provided in the flange 32, and both ends of the coil 10 may be pulled out through the groove to the outside of the flange 32 as viewed in the winding axis direction. The coil 10 pulled out through the groove may be wound around a separately provided winding terminal.

[0106] Like the notches (notch 71 and notch 82) in the second insulating tape, a notch may be provided at one end of the interlayer tape 50 or the second interlayer tape 52. Specifically, a notch may be provided at one end of the interlayer tape 50 by cutting out a corner in a rectangular shape. In this case, after the first coil 11 is wound around the winding shaft 31, the interlayer tape 50 is arranged on top of the first winding portion 11b before the first return portion 11f (see FIG. 4A) is arranged. Specifically, the interlayer tape 50 is arranged so that one end (terminal portion 11h (see FIG. 4A)) of the first winding portion 11b is located within the notch in the interlayer tape 50 when viewed in the radial direction. Once the interlayer tape 50 is arranged, the first coil 11 is bent at the terminal 333 at the terminal portion 11h. As a result, the first return portion 11f is arranged on the upper side of the interlayer tape 50. That is, the interlayer tape 50 is disposed between the first return portion 11 f and the first winding portion 11 b. The end of the winding of the first winding portion 11 b is fixed by the interlayer tape 50 disposed in the upper layer, so that the first coil 11 can be easily bent at the end portion 11 h.

[0107] In the above-described embodiment, the cutouts (cutouts 71 and 82) in the peripheral tape 70 and the partition tape 80 are provided at the lower end of both longitudinal ends of the wide portion or the partition portion 81, respectively. However, this is not limited to this. The cutouts may be provided at the upper end of both longitudinal ends of the wide portion or the partition portion 81. For example, the cutout 82 of the partition tape 80 shown in FIG. 12( a) may be provided on the side of the partition portion 81 on which the surface tape portion 83 is provided. In this case, the cutout 82 may be recessed in the longitudinal direction in the area on the inside of the surface tape portion 83 in the winding axis direction, on the side of the partition portion 81 along the winding axis direction.

[0108] In the above-described embodiment, a portion of the coil 10 (for example, the second start portion 12e in FIG. 1 or the third start portion 13a in FIG. 13B ) is wound on the lower side of the surface creeping tape 60, which is wound in the same layer as the coil 10, but this is not limited to this. For example, the surface creeping tape 60 wound in the same layer may be wound radially outward (upper layer) from the second start portion 12e or the third start portion 13a. In this case, for example, when winding the integrated insulating tape 40, the entire interlayer tape portion 41 is wound around the winding shaft 31, and then the surface creeping tape portion 42 is wound around the winding shaft 31, and then the second start portion 12e is positioned on the upper side of the surface creeping tape portion 42. This allows the interlayer tape portion 41 and the surface creeping tape portion 42 to be wound continuously, thereby reducing the number of manufacturing steps.

[0109] The above embodiments encompass the following technical concepts: (1) A transformer having a bobbin extending in a winding axis direction, a first coil wound on the inner side of multiple coils wound in layers around the bobbin, a second coil wound on the outer side of the first coil, an interlayer tape wound between the first coil and the second coil, and one or more creepage tapes wound on the outer side of the first coil or the second coil in the winding axis direction, wherein at least a portion of the creepage tape and the interlayer tape form a single insulating tape; (2) The transformer described in (1), in which the creepage tape wound on the outer side of the second coil in the winding axis direction and the interlayer tape form a single insulating tape; (3) The transformer described in (2), in which the creepage tape wound on the outer side of the first coil in the winding axis direction and the interlayer tape are separate members. (4) The transformer according to any one of (1) or (2), wherein the surface tape wound around the outside of the first coil in the winding axis direction and the interlayer tape form the insulating tape of a single piece. (5) The transformer according to any one of (1) to (4), wherein the second insulating tape is wound around the outside of a portion of the second coil and includes a wide portion having a width equal to or greater than the length of the winding axis direction of the winding shaft portion of the bobbin, a notch is provided at one end in the longitudinal direction of the wide portion, and the second coil is disposed across the inside and outside of the second insulating tape through the notch. (6) The transformer according to (5), wherein the notch is provided at one end of the wide portion on the outside in the winding axis direction, and another portion of the second coil disposed outside the second insulating tape is wound through the notch from the one end to the other opposite to the one end along the winding axis direction. (7) A transformer described in any one of (1) to (6), wherein a portion of the second coil is disposed between the interlayer tape and the surface tape formed of a single member with the interlayer tape and wound around the outside of the second coil in the winding axis direction.(8) The transformer according to any one of (1) to (7), wherein both ends of the first coil are drawn out to one side in the winding axis direction, both ends of the second coil are drawn out to the other side in the winding axis direction, and the creeping tape is wound around at least the other side of the first coil and at least the one side of the second coil. (9) The transformer according to (8), wherein the creeping tape wound around the other side of the first coil, the creeping tape wound around the one side of the second coil, and the interlayer tape form a single insulating tape. (10) The transformer according to any one of (1) to (7), wherein both ends of the first coil and the second coil are drawn out to one side in the winding axis direction, and the creeping tape is wound around the one side of the first coil and the second coil and the other side of the first coil or the second coil in the winding axis direction. (11) The transformer according to (10), wherein the total length in the winding axis direction of the surface tape arranged on the other side of the first coil or the second coil is equal to the respective lengths of the surface tape arranged on the one side of the first coil and the second coil. (12) A bobbin set including a bobbin extending in the winding axis direction and an insulating tape having a width equal to or greater than the length in the winding axis direction of a winding shaft portion sandwiched between a pair of flanges provided on the bobbin at a distance from each other in the winding axis direction, wherein the insulating tape has a surface tape portion on the outside in the width direction at one end of the longitudinal direction of the insulating tape, the surface tape portion having a length equal to or greater than the circumferential length of the winding shaft portion.(13) A method for manufacturing a transformer having a bobbin extending in a winding axis direction, a first coil wound inside of multiple coils wound in layers around the bobbin, a second coil wound outside the first coil, and an insulating tape wound around the bobbin, wherein the insulating tape has an interlayer tape portion wound between the first coil and the second coil and a creeping tape portion wound outside the first coil or the second coil in the winding axis direction, the interlayer tape portion and the creeping tape portion being formed as a single insulating tape, the method including: a first coil winding step of winding the first coil around the winding shaft portion, an insulating tape winding step of winding a portion of the interlayer tape portion and the creeping tape portion continuously around the bobbin, and a second coil winding step of winding the second coil outside the interlayer tape portion. (14) The transformer according to any one of (1) to (10), wherein the interlayer tape and the creeping tape are configured by laminating a base layer and an adhesive layer. (15) The transformer according to any one of (1) to (10), wherein the width of the interlayer tape is equal to or greater than the length of the winding shaft portion in the winding axis direction, and the length of the interlayer tape in the longitudinal direction is equal to or greater than the length of the outer circumferential surface of the first coil wound inside the interlayer tape in the radial direction of the bobbin. (16) The transformer according to any one of (1) to (10), wherein the surface creepage tape is arranged inside both side edges of the interlayer tape extending in the longitudinal direction of the interlayer tape in the winding axis direction. (17) The transformer according to any one of (5) to (10), wherein the notch is formed by cutting out one side in the winding axis direction at one end of the longitudinal direction of the wide portion in a rectangular or square shape. (18) A transformer described in any one of (1) to (10), in which the first coil or the second coil is wound in layers across multiple layers, a partition tape is wound between a lower layer portion wound on the inside of the multiple layers and an upper layer portion wound outside the lower layer portion, and the partition tape has a partition portion arranged between the lower layer portion and the upper layer portion and a surface tape portion wound outside the winding axis direction of the upper layer portion.(19) The transformer according to (9), wherein the insulating tape has a rectangular interlayer tape portion, and the creeping tape portion is provided at a diagonal position of the rectangular interlayer tape portion, extending in the length direction of the interlayer tape portion. (20) The transformer according to (11), wherein the width of the creeping tape wound around the other side of one of the first coil and the second coil, which has a longer winding width to be wound around the winding shaft portion, is smaller than the width of the creeping tape wound around the other side of the other coil, which has a shorter winding width to be wound around the winding shaft portion. (21) The method for manufacturing a transformer according to (13), wherein, in the insulating tape winding step, the creeping tape portion is wound successively after the interlayer tape portion is wound.

Claims

1. A bobbin extending in a winding axis direction; a first coil wound on an inner side of the plurality of coils wound in layers around the bobbin; A second coil wound around the outside of the first coil; an interlayer tape wound between the first coil and the second coil; and one or more creepage tapes wound around an outer side of the first coil or the second coil in the winding axis direction, A transformer, wherein at least a portion of the surface tape and the interlayer tape form a single insulating tape.

2. 2. The transformer according to claim 1, wherein the surface tape and the interlayer tape wound around the outside of the second coil in the winding axis direction form the insulating tape of a single member.

3. 3. The transformer according to claim 2, wherein the surface tape and the interlayer tape wound around the outside of the first coil in the winding axis direction are separate members.

4. The surface tape and the interlayer tape wound around the outside of the second coil in the winding axis direction are the insulating tape of a single member, 2. The transformer according to claim 1, wherein the surface tape and the interlayer tape wound around the outside of the first coil in the winding axis direction form the insulating tape of a single member.

5. a second insulating tape wound around the outside of a portion of the second coil and including a wide portion having a width equal to or greater than a length of the winding axis direction of the winding shaft portion of the bobbin; A notch is provided at one end of the wide portion in the longitudinal direction, The transformer according to claim 1 , wherein the second coil is disposed across the inside and outside of the second insulating tape through the cutout portion.

6. the notch is provided on one outer side in the winding axis direction at the one end of the wide portion, 6. The transformer according to claim 5, wherein another part of the second coil, which is passed through the cutout and arranged outside the second insulating tape, is wound along the winding axis direction from the one side to the other side opposite to the one side.

7. 5. The transformer according to claim 1, wherein a portion of the second coil is disposed between the interlayer tape and the surface tape formed of a single member with the interlayer tape and wound outside the second coil in the winding axis direction.

8. both ends of the first coil are drawn out to one side in the winding axis direction, Both ends of the second coil are drawn out to the other side in the winding axis direction, The transformer according to claim 1 , wherein the surface tape is wound around at least the other side of the first coil and at least the one side of the second coil.

9. 9. The transformer according to claim 8, wherein the surface tape wound around the other side of the first coil, the surface tape wound around the one side of the second coil, and the interlayer tape are a single insulating tape.

10. both ends of the first coil and the second coil are pulled out to one side in the winding axis direction, 5. The transformer according to claim 1, wherein the surface tape is wound around the one side of the first coil and the second coil and the other side of the first coil or the second coil in the winding axis direction.

11. The total length of the surface tape arranged on the other side of the first coil or the second coil in the winding axis direction is the length of each of the surface tapes arranged on the one side of the first coil and the second coil is equal to the length of each of the surface tapes arranged on the one side of the first coil and the second coil; 11. The transformer according to claim 10, wherein a width of the surface tape wound around the other side of one of the first coil and the second coil, which has a larger winding width, is shorter than a width of the surface tape wound around the other side of the other of the first coil and the second coil, which has a smaller winding width.

12. A bobbin extending in a winding axis direction; an insulating tape having a width equal to or greater than a length in the winding axis direction of a winding shaft portion sandwiched between a pair of flange portions spaced apart from each other in the winding axis direction of the bobbin, a bobbin set, the insulating tape having a surface tape portion on the outside in the width direction at one end in the longitudinal direction of the insulating tape, the surface tape portion having a length equal to or greater than the circumferential length of the winding shaft portion.

13. A bobbin extending in a winding axis direction; a first coil wound on an inner side of the plurality of coils wound in layers around the bobbin; A second coil wound around the outside of the first coil; and an insulating tape wound around the bobbin, The insulating tape is an interlayer tape portion wound between the first coil and the second coil; a surface tape portion wound around the outside of the first coil or the second coil in the winding axis direction, the interlayer tape portion and the surface tape portion are formed as a single insulating tape, a first coil winding step of winding the first coil around the bobbin; an insulating tape winding step of continuously winding a portion of the interlayer tape portion and the surface tape portion around the bobbin; a second coil winding step of winding the second coil around the outer side of the interlayer tape portion; A method for manufacturing a transformer comprising the steps of: