JP7506547B2 - Trance - Google Patents

Description

The present invention relates to a transformer.

Conventionally, a transformer having a spirally wound planar coil is known. This transformer includes multiple planar coils and a bobbin that holds the multiple planar coils in a stacked state in the thickness direction. The planar coils are held on the bobbin by being inserted into slots formed in the bobbin. Planar coils of different lengths may also be used to accommodate different input or output voltages. Even in this case, the planar coils are held using the same bobbin. However, this type of transformer has a problem in that it has a large area when viewed from above.

In contrast, the transformer in Patent Document 1 has a cylindrical bobbin and a coil wound cylindrically along the outer circumference and axis of the bobbin. The cylindrical coil is therefore smaller than a planar coil. Furthermore, the bobbin has two halves that have a U-shaped cross section and are assembled so that their openings face each other. By adjusting the amount that the two halves overlap, the size of the hollow space formed between the two halves can be adjusted. This makes it possible to change the allowable number of iron cores that can be installed in the hollow space. Therefore, the same bobbin can be used to construct transformers with different capabilities.

JP 2002-313655 A

However, compared to flat coils, cylindrically wound coils have a structure that makes it difficult to dissipate heat. For this reason, there has been a demand for transformers with a structure that is excellent at dissipating heat. In addition, when manufacturing transformers, the number of turns in the coil varies depending on the capacity of the transformer, and there is an ongoing need to improve bobbins to deal with the time and cost involved in preparing multiple types of bobbins of different sizes for each type of transformer with different capacities.

In one feature of the present disclosure, the transformer has a cylindrical bobbin and a coil wound around the outer circumference of the bobbin and along the axis. The coil has a protruding portion that protrudes radially. The bobbin has a positioning portion that faces the protruding portion of the coil in the axial direction. The positioning portion cooperates with the protruding portion to regulate the movement of the coil in the axial direction relative to the bobbin. Therefore, the height position of the coil relative to the bobbin is determined even for coils with different numbers of turns and different heights. Therefore, even for coils with different heights, the coils can be positioned relative to the bobbin at a height position that is suitable for heat dissipation. Another advantage is that one type of bobbin can be used to accommodate multiple types of coils with different numbers of turns.

In another feature of the present disclosure, the protrusion protrudes radially outward from a first end in the axial direction of the coil. The first end of the coil abuts in the axial direction against a core arm extending radially from an end of a core leg of a core body that penetrates a bobbin. Thus, heat from the coil is transferred from the first end of the coil to the core arm. A protrusion is then formed at the first end. Therefore, the height of the coil can be determined so that the protrusion can reliably abut the first end against the core member.

In another feature of the present disclosure, the protrusion protrudes radially outward from a first end in the axial direction of the coil. The coil has a terminal extending from the protrusion toward a second end opposite the first end. Thus, the terminal of the coil extends axially along the coil body outside the coil body by utilizing the protrusion. Therefore, the length of the terminal can be adjusted to be longer or shorter.

In another feature of the present disclosure, the transformer has a second coil extending along the outer periphery of the bobbin. The bobbin has a holding portion that holds the second coil. An installation groove that houses the coil is formed on the inner periphery side of the holding portion of the bobbin. A first opening that allows the inner periphery of the second coil to face the outer periphery of the coil is formed in the bobbin. A second opening that allows the inner periphery of the coil to face the core leg of the core body of the core member inserted into the bobbin is formed in the bobbin. The inner periphery of the second coil and the outer periphery of the coil can be thermally conductive via the filler filled in the first opening. Therefore, heat from the coil is transferred from the inner periphery of the coil to the core leg. Moreover, heat from the coil is also transferred from the outer periphery of the coil to the second coil. As a result, heat generated by the coil is effectively generated.

FIG. 2 is a top perspective view of the transformer according to the first embodiment. FIG. 2 is an exploded perspective view of the transformer of FIG. 1 . FIG. 3 is a bottom perspective view of the transformer of FIG. 2 . FIG. 3 is a top perspective view of the bobbin and the first coil attached to the bobbin in FIG. 2 . FIG. 5 is a bottom perspective view of FIG. 4 . FIG. 5 is a plan view of FIG. 7 is a cross-sectional view taken along line VII-VII of the transformer shown in FIG. 6 with the core body attached thereto. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6 with the core body attached to the transformer. FIG. 11 is a top perspective view of a transformer according to a second embodiment. FIG. 10 is a front view of the transformer of FIG. FIG. 5 is a top perspective view of a part corresponding to FIG. 4 in a third embodiment. FIG. 12 is a plan view of FIG. FIG. 13 is a side view of the part corresponding to FIG. 4 in the fourth embodiment, showing an example in which the first coil has three turns. FIG. 13 shows an example in which the first coil has five turns. FIG. 13 shows an example in which the first coil has seven turns.

The first embodiment will be described with reference to Figures 1 to 8. The transformer 1 shown in Figure 1 is, for example, an element mounted inside a DC-DC converter (not shown). As shown in Figures 2 and 3, the transformer 1 includes a bobbin assembly 5 and a core body 9 that is assembled to the bobbin assembly 5 to form a magnetic circuit. The bobbin assembly 5 includes a first coil 3, a second coil 4, and a bobbin 2 that holds the first coil 3 and the second coil 4.

As shown in Figures 2 and 3, the bobbin 2 has a cylindrical bobbin body 10. The bobbin body 10 is a cylindrical resin member having a substantially U-shape, and has a first side portion 13, a second side portion 17, and a third side portion 19.

As shown in Figures 4, 5, and 6, the first side portion 13 has a first opening 15, a second opening 16, and a third opening 16a. The second side portion 17 has a notch 18. The third side portion 19 has a first opening 21, a second opening 22, and a third opening 22a. A notch 12 is formed between the tip of the first side portion 13 and the tip of the third side portion 19. Specifically, the notch 12 is open so that the upper and lower sides are connected. The first openings 15 and 21 are open on the lower side. The notch 18 is open on the lower side. As shown in Figures 5 and 7, the second openings 16 and 22 are open on the lower side. The third openings 16a and 22a are open on the upper side.

As shown in FIG. 6, the bobbin body 10 has mounting grooves 14, 20 into which the first coil body 30 of the first coil 3 is inserted. Specifically, the mounting grooves 14, 20 are formed in the opposing first side portion 13 and third side portion 19, respectively. The mounting grooves 14, 20 open downward so that the first coil body 30 can be inserted from below. The mounting grooves 14, 20 are located near the inner circumferential surfaces of the first side portion 13 and the third side portion 19 so that the first coil 3 is located on the inner circumferential side of the second coil 4. The groove width of the mounting grooves 14, 20 is set slightly wider than the wire diameter of the first coil 3. The first coil 3 is inserted into the mounting grooves 14, 20 by a fixing adhesive (not shown) or a claw (not shown) applied to the mounting grooves 14, 20, or by pressing the mounting grooves 14, 20 into a narrow width, and is held in a state of being positioned with respect to the axis T direction described below.

2 and 3 , the second coil 4 is held in the bobbin body 10, and at least a portion of the second coil 4 is embedded. The second coil 4 is insert-molded into the bobbin body 10. That is, the bobbin body 10 includes a holding portion into which the second coil 4 is inserted. More specifically, the second coil 4 is held in the opposing first side portion 13 and third side portion 19.
The bobbin body 10 is provided with a positioning portion 27 that determines the position of the first coil 3 relative to the bobbin 2 .

3 and 6, the positioning portion 27 is located at the corner 26 that connects the second side 17 and the third side 19 of the bobbin body 10. The positioning portion 27 protrudes from the lower surface of the corner 26 and is, for example, rectangular. The positioning portion 27 has a positioning surface 27a on the lower side. The positioning surface 27a faces (cooperates with) the protruding portion 33 of the first coil 3 to regulate the movement of the first coil 3 in the vertical direction (the direction of the axis T) relative to the bobbin 2. The positioning portion 27 has an arc-shaped round portion on the edge that faces the first side 13. The arc shape of the round portion is along the bent portion that connects the protruding portion 33 of the first coil 3 and the first terminal 34. Therefore, the bent portion of the first coil 3 can be prevented from hitting the corner of the positioning portion 27, and the protruding portion 33 of the first coil 3 can be reliably abutted against the positioning surface 27a.

2 and 3, the first coil 3 includes a first coil body 30 and a first terminal 34 and a second terminal 35 extending from the first coil body 30. The first coil body 30 is wound in a cylindrical shape along the axis T of the bobbin body 10. As shown in FIG. 6, specifically, the first coil body 30 is rectangular and has a length in the longitudinal direction (the vertical direction of the paper in FIG. 6) longer than the corresponding length of the bobbin body 10. As a result, both ends of the longitudinal direction of the first coil body 30 are exposed from the first coil body 30. The length of the first coil body 30 perpendicular to the longitudinal direction (the horizontal direction of the paper in FIG. 6) is equal to the corresponding length of the bobbin body 10. Therefore, both ends of the first coil body 30 are accommodated in the bobbin body 10.

2 and 3, the first terminal 34 of the first coil body 30 extends upward from the first end 31 in the direction of the axis T of the first coil body 30 beyond the second end 32. The second terminal 35 extends upward from the second end 32 of the first coil body 30 in parallel with the first terminal 34. A protrusion 33 is formed between the first end 31 and the first terminal 34 of the first coil body 30. The protrusion 33 protrudes radially outward from the first coil body 30. For example, the protrusion 33 protrudes in a substantially L-shape from the outer circumferential surface of the first coil body 30.

The first coil 3 shown in FIG. 2 is a triple-layer insulated wire. Specifically, the first coil 3 has a first PET layer covering the copper wire, a second PET layer covering the first PET layer, and a nylon layer covering the second PET layer. The outermost periphery of the triple-layer insulation is composed of a fusion layer made of a thermoplastic material. Therefore, the shape of the first coil 3 is determined by applying heat, or by forming a predetermined shape and then applying heat, which fuses and fixes the fusion layers together at adjacent points to determine the shape.

2 and 3, the second coil 4 includes a second coil body 40, and a first terminal 41 and a second terminal 42 extending axially from the second coil body 40. As shown in Fig. 6, the second coil body 40 is substantially U-shaped and extends along the first side portion 13, the second side portion 17, and the third side portion 19 of the bobbin 2.
The surface of the second coil 4 is coated with enamel. Therefore, the second coil 4 also has insulating properties with respect to the first coil 3. As shown in Fig. 7, the width of the second coil 4 itself (the height of the second coil 4) is about 70% of the height of the first coil body 30 of the first coil 3.

As shown in Figures 2 and 3, the first coil 3 is inserted from below the bobbin 2 on which the second coil 4 is insert molded, along the outer circumference of the first side portion 13 to the third side portion 19. Specifically, the first coil 3 is inserted into the installation grooves 14 and 20. As a result, as shown in Figure 8, the protruding portion 33 of the first coil 3 abuts against the positioning surface 27a of the positioning portion 27 of the bobbin 2 in the direction of the axis T. Thus, movement of the first coil 3 in the direction of the axis T relative to the bobbin 2 is restricted.

As shown in FIG. 5, the first coil body 30 is inserted into the mounting grooves 14, 20 of the bobbin 2 and is held so as not to fall off the bobbin 2. The bobbin assembly 5 is assembled as described above. As shown in FIG. 6, the first openings 15, 21 of the bobbin 2 allow the inner peripheral surface 40a of the second coil body 40 and the outer peripheral surface 30b of the first coil body 30 to face each other.

As shown in Figures 1 to 3, the core body 9 is a core made of ferrite (magnetic material) that forms a magnetic circuit, and includes an E-shaped core member 6 and an I-shaped core member 7. The E-shaped core member 6 includes a core leg 60, a core arm 62, and a pair of outer legs 64. The core leg 60 passes through the bobbin 2. The core arm 62 extends radially from an end 61 of the core leg 60. The pair of outer legs 64 protrude from both ends of the core arm 62 and are located on both sides of the core leg 60. The I-shaped core member 7 is a rectangular core member that faces the E-shaped core member 6.

As shown in Figure 7, the transformer 1 is completed when the core leg 60 of the E-shaped core member 6 is inserted into the bobbin assembly 5 and the end faces 60a, 64a of the E-shaped core member 6 are bonded to the inner surface 70 of the I-shaped core member 7. The completed transformer 1 is housed in a case (not shown), which is filled with potting material, and the entire exterior and interior are soaked in a filler (not shown, potting material) with high thermal conductivity. The potting material seeps into the openings described below and into the gaps between the core and the ends.

As shown in FIG. 7, in the transformer 1, the second openings 16 and 22 allow the inner circumferential surface 30a of the first coil body 30 of the first coil 3 to face the outer circumferential surface 60b of the core leg 60 of the E-shaped core member 6 inserted into the bobbin 2. The third openings 16a and 22a allow the outer circumferential surface 40b of the second coil body 40 to face the inner circumferential surface 64b of the outer leg 64 of the E-shaped core member 6.

As shown in FIG. 8, in the transformer 1, as already explained, the protrusion 33 of the first coil 3 abuts against the positioning surface 27a of the positioning portion 27 of the bobbin 2 in the direction of the axis T. Therefore, as shown in FIG. 8, the first coil 3 is not close to the I-shaped core member 7, but close to the core arm 62 of the E-shaped core member 6. Therefore, the first end 31 of the first coil 3 abuts against the inner surface 63 of the core arm 62 of the E-shaped core member 6 in the direction of the axis T. As a result, heat generated in the first coil 3 can be released to the core arm 62 of the E-shaped core member 6 via the filler or the insulating layer, or both.

As shown in FIG. 7, the first side 13 and the third side 19 of the bobbin 2 are provided with a first opening 15 and a first opening 21. Therefore, the outer peripheral surface 30b of the first coil body 30 and the inner peripheral surface 40a of the second coil body 40 abut in the width direction of the bobbin 2 through both the first openings 15, 21. Therefore, heat generated in the first coil 3 can be released to the second coil 4 through the filler or the insulating layer, or both. Conversely, heat generated in the second coil 4 can be released to the first coil 3 through the filler or the insulating layer, or both.

As shown in FIG. 7, the first side 13 and the third side 19 of the bobbin 2 have a second opening 16 and a second opening 22. Therefore, the inner surface 30a of the first coil body 30 and the outer surface 60b of the core leg 60 of the E-shaped core member 6 face each other through the second openings 16 and 22. Therefore, heat generated in the first coil 3 can be dissipated to the core leg 60 of the E-shaped core member 6 through the filler material.

As shown in FIG. 7, the first side 13 and the third side 19 of the bobbin 2 are provided with the third opening 16a and the third opening 22a. Therefore, the outer peripheral surface 40b of the second coil body 40 and the inner peripheral surface 64b of the outer leg 64 of the E-shaped core member 6 face each other through the third openings 16a and 22a. Therefore, the heat generated in the second coil 4 can be dissipated to the outer leg 64 of the E-shaped core member 6 through the filling material.

As shown in FIG. 8, the transformer 1 according to the first embodiment is configured as described above. The protrusion 33 of the first coil 3 abuts against the positioning surface 27a of the positioning portion 27 of the bobbin 2 in the direction of the axis T. Therefore, even if the first coils 3 have different numbers of turns and different heights, the height position of the first coil 3 relative to the bobbin 2 is determined. Therefore, even if the first coils 3 have different numbers of turns and different heights, the first coils 3 can be positioned relative to the bobbin 2 at a height position suitable for heat dissipation. Another advantage is that only one type of bobbin 2 can accommodate multiple types of first coils 3 with different numbers of turns.

As shown in Figures 7 and 8, the protrusion 33 of the first coil 3 protrudes radially outward from the first end 31 in the direction of the axis T of the first coil 3. The first end 31 of the first coil 3 abuts in the direction of the axis T against the core arm 62 of the E-shaped core member 6 that extends radially from the end 61 of the core leg 60 of the E-shaped core member 6 that penetrates the bobbin 2. Therefore, the heat of the first coil 3 is transferred from the first end 31 of the first coil 3 to the E-shaped core member 6. The protrusion 33 is then formed on the first end 31. Therefore, the height of the first coil 3 can be determined so that the protrusion 33 can reliably abut the first end 31 against the E-shaped core member 6.

As shown in Figures 5 and 8, the protrusion 33 of the first coil 3 protrudes radially outward from the first end 31 in the direction of the axis T of the first coil 3. The first coil 3 has a first terminal 34 extending from the protrusion 33 toward the second end 32 opposite the first end 31. Therefore, by utilizing the protrusion 33, the first terminal 34 of the first coil 3 extends in the axial direction along the first coil body 30 outside the first coil body 30. Therefore, the length of the terminal can be adjusted to be longer or shorter.

As shown in FIG. 7, the transformer 1 has a second coil 4 extending along the outer periphery of the bobbin 2. The second coil 4 is inserted into the bobbin 2. Installation grooves 14, 20 for accommodating the first coil 3 are formed on the inner periphery of the bobbin 2. First openings 15, 21 are formed in the bobbin 2, which allow the inner periphery 40a of the second coil 4 to face the outer periphery 30b of the first coil 3. Second openings 16, 22 are formed in the bobbin 2, which allow the inner periphery 30a of the first coil 3 to face the core leg 60 of the E-shaped core member 6 inserted into the bobbin 2. The inner periphery 40a of the second coil 4 and the outer periphery 30b of the first coil 3 can be thermally conductive through the filler filled in the first openings 15, 21. Therefore, the heat from the first coil 3 is transferred from the inner periphery 30a of the first coil 3 to the core leg 60. Moreover, the heat from the first coil 3 is also transferred from the outer surface 30b of the first coil 3 to the second coil 4. As a result, the heat generated by the first coil 3 is dissipated effectively.

The second embodiment will be described with reference to Figs. 9 and 10. The transformer 101 of the second embodiment is another example of positioning with respect to the axis T direction. The second terminal 35 of the first coil 3 has a substantially horizontal V-shaped protrusion 35a formed in the middle part in the direction of the axis T. The protrusion 35a is bent in the radial direction (left and right direction in Fig. 10) from the second terminal 35. When the first coil 3 is attached to the bobbin 2, the second terminal 35 of the first coil 3 is inserted into the insertion hole 25a of the second insertion tube 25 of the bobbin 2. As a result, the protruding tip 35b of the protrusion 35a of the second terminal 35 abuts against the positioning portion 25b, which is the entrance edge of the insertion hole 25a, in the direction of the axis T. As a result, the axial movement of the first coil 3 with respect to the bobbin 2 is restricted.

Therefore, similar to the transformer 1 of the first embodiment, the height position of the first coil 3 relative to the bobbin 2 is determined even if the first coil 3 has a different number of turns and a different height. Therefore, even if the first coil 3 has a different number of turns and a different height, the first coil 3 can be positioned relative to the bobbin 2 at a height position suitable for heat dissipation. As a result, the transformer 101 of the second embodiment can obtain the same effect as the transformer 1 of the first embodiment. Note that the protrusion 33 described in the first embodiment is not necessary for the first coil 3 of this transformer 101.

The third embodiment will be described with reference to Figures 11 and 12. Compared to the bobbin assembly 5 of the first embodiment, the bobbin assembly 205 of the third embodiment has a configuration in which the heat generated by the first coil 3 is dissipated more effectively.

As shown in Figures 12 and 14, in the bobbin assembly 205, the outer peripheral surface 30b of the first coil body 30 of the first coil 3 and the inner peripheral surface 40a of the second coil body 40 of the second coil 4 at the second side portion 17 abut in the longitudinal direction of the rectangular bobbin 2. Also, similar to the bobbin assembly 5, the outer peripheral surface 30b of the first coil body 30 of the first coil 3 and the inner peripheral surface 40a of the second coil body 40 of the second coil 4 at the first side portion 13 and the third side portion 19 abut in the width direction of the rectangular bobbin 2.

As a result, the number of contact points between the first coil 3 and the second coil 4 increases from two (first side 13, third side 19) to three (first side 13, second side 17, third side 19). This allows the heat generated by the first coil 3 to be dissipated more effectively. The structure (protrusion and positioning portion) that determines the height position of the first coil 3 relative to the bobbin 2 can be the structure of the first or second embodiment.

The fourth embodiment will be described with reference to Figures 13 to 15. The transformer 301 of the fourth embodiment has a configuration that allows the shape of the first coil 3 to be simplified compared to the transformers 1 and 101 of the first and second embodiments. The outer periphery of the bobbin 2 of the transformer 301 has multiple step surfaces with different heights along the direction of the axis T. As the multiple step surfaces, for example, three step surfaces (first step surface 2a, second step surface 2b, and third step surface 2c) are provided.

As shown in FIG. 13, the first end 31 of the first coil 3 with 3 turns attached to the bobbin 2 abuts against the first step surface 2a in the direction of the axis T. As shown in FIG. 14, the first end 31 of the first coil 3 with 5 turns attached to the bobbin 2 abuts against the second step surface 2b in the direction of the axis T. As shown in FIG. 15, the first end 31 of the first coil 3 with 7 turns attached to the bobbin 2 abuts against the third step surface 2c in the direction of the axis T.

Compared to a first coil 3 with 3 turns, a first coil 3 with 5 turns protrudes in the radial direction. Compared to a first coil 3 with 5 turns, a first coil 3 with 7 turns protrudes in the radial direction. Therefore, as with the transformers 1 and 101 of the first and second embodiments, the height position of the first coil 3 relative to the bobbin 2 is determined even for first coils 3 with different numbers of turns and different heights. Therefore, even for first coils 3 with different heights, the first coil 3 can be positioned relative to the bobbin 2 at a height position suitable for heat dissipation. As a result, the transformer 301 of the fourth embodiment can also obtain the same effects as the transformers 1 and 101 of the first and second embodiments.

In the first coil 3 of the transformer 301, the protrusions 33, 35a described in the first and second embodiments are not necessary. Therefore, the shape of the second coil 3 can be simplified. In the transformer 301, the second end 32 of the first coil 3 attached to the bobbin 2 abuts against the inner surface 70 of the I-shaped core member 7 in the direction of the axis T. Therefore, heat generated in the second coil 3 can be dissipated to the inner surface 70 of the I-shaped core member 7 via the filler.

Although the first to fourth embodiments have been described with reference to the above structure, it will be apparent to those skilled in the art that many alternatives, improvements, and modifications are possible without departing from the scope of the present invention. Therefore, the first to fourth embodiments may include all alternatives, improvements, and modifications that do not depart from the spirit and scope of the appended claims. For example, the first to fourth embodiments are not limited to a particular structure, and may be modified as follows:

As described above, the transformer has a first coil (coil) 3 and a second coil 4. Alternatively, the transformer may have a ring-shaped second coil as a coil. As described above, the transformer has a ring-shaped first coil 3 and a U-shaped second coil 4. Alternatively, the transformer may have a ring-shaped first coil 3 and a ring-shaped second coil 4. As described above, the transformer has a second coil 4 that is insert molded into the bobbin 2. Alternatively, the transformer may have a second coil 4 that is attached to the bobbin 2 after molding.

As described above, the first coil 3 has a protrusion 33 that protrudes radially outward from the first coil body 30. Alternatively, the first coil 3 may have a protrusion 33 that protrudes radially inward from the first coil body 30. As described above, the protrusion 33 is formed on the first end 31 of the first coil body 30 of the first coil 3. Alternatively, the protrusion 33 may be formed on the second end 32 of the first coil body 30 of the first coil 3. As described above, the first coil 3 is positioned on the bobbin 2 so as to be brought closer to the lower end side (E-shaped core member 6 side) of the bobbin 2. Alternatively, the first coil 3 may be positioned on the bobbin 2 so as to be brought closer to the upper end side (I-shaped core member 7) of the bobbin 2.

As described above, the installation grooves 14, 20 in which the first coil 3 is installed are formed on the first side 13 and the third side 19 of the bobbin 2. Alternatively, one of the installation grooves 14, 20 may be formed on the second side 17 of the bobbin 2. In other words, it is sufficient that the installation groove is formed in at least one of the first side 13 to the third side 19 of the bobbin 2. As described above, the openings of the installation grooves 14, 20 are formed downward. Alternatively, the openings of the installation grooves 14, 20 may be formed upward.

As described above, the first openings 15, 21 that face the inner circumferential surface 40a of the second coil 4 and the outer circumferential surface 30b of the first coil 3 are formed in the first side 13 and the third side 19 of the bobbin 2. Alternatively, the first openings 15, 21 may be formed in the second side 17 of the bobbin 2. In other words, it is sufficient that the first openings are formed in at least one of the first side 13 to the third side 19 of the bobbin 2.

As described above, the second openings 16, 22 that face the inner circumferential surface 30a of the first coil 3 and the outer circumferential surface 60b of the core leg 60 of the E-shaped core member 6 of the core body 9 are formed in the first side 13 and the third side 19 of the bobbin 2. Alternatively, the second openings 16, 22 may be formed in the second side 17 of the bobbin 2. In other words, it is sufficient that the second openings are formed in at least one of the first side 13 to the third side 19 of the bobbin 2.

As described above, the core body 9 has two core members (E-shaped core member 6, I-shaped core member 7). Alternatively, the core body 9 may have one core member. As described above, the shapes of the two core members of the core body 9 are E-shaped and I-shaped. Alternatively, the shapes of the two core members of the core body 9 may be E-shaped and E-shaped.

As described above, the bobbin 2 is annular by utilizing the second coil 4. Alternatively, the bobbin 2 may be annular by utilizing the first coil 3. As described above, the bobbin 2 is inserted into three sides of the second coil 4 (a total of three sides: a side corresponding to the first side portion 13, a side corresponding to the second side portion 17, and a side corresponding to the third side portion 19). Alternatively, the bobbin 2 may be inserted into two sides of the second coil 4 (a total of two sides: a side corresponding to the first side portion 13 and a side corresponding to the third side portion 19). Alternatively, the bobbin 2 may be inserted into at least one side of the second coil 4 (at least one side of the side corresponding to the first side portion 13, a side corresponding to the second side portion 17, and a side corresponding to the third side portion 19). Also, the bobbin 2 may be inserted into only the corners of the second coil 4.
The first coil 3 and the second coil 4 may be arranged inside and outside the core body 9 in a reversed manner. Also, instead of inserting them, the first coil 3, the second coil 4, and the bobbin 2 may be prepared separately and then assembled.

1 Transformer 2 Bobbin 3 First coil (coil)
4 Second coil 6 E-shaped core member 7 I-shaped core member 9 Core body 14 Installation groove 15 First opening 16 Second opening 20 Installation groove 21 First opening 22 Second opening 25 Second insertion tube 25a Insertion hole 25b Positioning portion 27 Positioning portion 27a Positioning surface 30a Inner peripheral surface 30b Outer peripheral surface 31 First end portion 32 Second end portion 33 Protrusion 34 First terminal (terminal)
35 Second terminal (terminal)
35a Protruding portion 35b Protruding tip 40a Inner peripheral surface 60 Core leg portion 62 Core arm T Axis

Claims (3)

A transformer,
A cylindrical bobbin;
A coil is wound around the outer periphery of the bobbin and along an axis,
The coil has a protrusion protruding in a radial direction,
the bobbin has a positioning portion facing the protruding portion of the coil in the axial direction, the positioning portion cooperating with the protruding portion to restrict movement of the coil relative to the bobbin in the axial direction ,
The protrusion protrudes radially outward from a first end of the coil in the axial direction, and the first end of the coil abuts in the axial direction against a core arm extending radially from an end of a core leg of a core body that penetrates the bobbin . 2. The transformer according to claim 1,
The protrusion protrudes radially outward from a first end of the coil in the axial direction, and the coil has a terminal extending from the protrusion toward a second end opposite the first end. 3. A transformer according to claim 1 or 2,
a transformer having a second coil extending along an outer periphery of the bobbin, the bobbin having a holding portion that holds the second coil, an installation groove formed on the inner periphery of the holding portion and that accommodates the coil, a first opening that allows the inner periphery of the second coil to face the outer periphery of the coil, and a second opening that allows the inner periphery of the coil to face the core leg of the core body inserted into the bobbin, and wherein thermal conduction is possible between the inner periphery of the second coil and the outer periphery of the coil via a filler filled in the first opening.

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