Coil component

Abstract

To provide a coil component which prevents cracking of a core caused by a resin and can improve reliability of the coil component.SOLUTION: A coil component 1 includes a bobbin 10 having cylinder parts 23 and 31, coils 3 and 7 wound around the cylinder parts 23 and 31, and a cover component 21 which is mounted on the bobbin 10 and covers the coils 3 and 7 from the outside, wherein the cover component 21 forms a resin filling space between the cylinder parts 23 and 31 by mounted on the bobbin 10, and forms an injection port for injecting a filling resin.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a coil component.

Background Art

[0002] Patent Document 1 discloses a coil component (reactor) in which a winding (coil) is wound around a cylindrical bobbin, and a core composed of two E-shaped core pieces is attached to the bobbin. In the coil component of Patent Document 1, resin is filled in a case that houses the bobbin, the winding, and the core, etc., and the bobbin, the winding, and the core are covered with the resin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the coil component of Patent Document 1, since the core is also covered with resin, stress is applied to the core due to thermal deformation of the resin in contact with the core and expansion and contraction of the resin due to moisture absorption. When stress acts on the core, the core may crack, so there is a problem that the reliability of the coil component is low.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a coil component that can prevent cracking of the core caused by resin and improve the reliability of the coil component.

Means for Solving the Problems

[0006] One aspect of the present invention includes a bobbin having a cylindrical portion, a winding wound around the cylindrical portion, and a cover component attached to the bobbin and covering the winding from the outside. By being attached to the bobbin, the cover component forms a resin filling space between itself and the cylindrical portion and forms an injection port for injecting resin. The bobbin has a first bobbin having a first cylindrical portion and a second bobbin having a second cylindrical portion through which the first cylindrical portion is inserted. The first cylindrical portion has an overlapping portion that overlaps the second cylindrical portion in the radial direction and a non-overlapping portion that is located adjacent to the overlapping portion in the axial direction and does not overlap the second cylindrical portion in the radial direction. The cover component has a first cover structure that overlaps the outside of the second cylindrical portion in the radial direction and a second cover structure that is formed adjacent to the second cylindrical portion in the axial direction, overlaps the outside of the first cylindrical portion in the radial direction, and is arranged axially with respect to the first cover structure. It is a coil component. Another aspect of the present invention includes a bobbin having a cylindrical portion, a winding wound around the cylindrical portion, and a cover component attached to the bobbin to cover the winding from the outside. By being attached to the bobbin, the cover component forms a resin filling space between the cover component and the cylindrical portion and forms an injection port for injecting resin. The bobbin has a first bobbin having a first cylindrical portion and a second bobbin having a second cylindrical portion located adjacent to the first cylindrical portion in the axial direction. The cover component is a coil component having a first cover structure that overlaps the outside of the second cylindrical portion in the radial direction and a second cover structure that is formed adjacent to the second cylindrical portion in the axial direction, overlaps the outside of the first cylindrical portion in the radial direction, and is arranged axially with respect to the first cover structure. Another aspect of the present invention includes a bobbin having a cylindrical portion, a winding wound around the cylindrical portion, and a cover component attached to the bobbin and covering the winding from the outside. The cover component, when attached to the bobbin, forms a resin filling space between itself and the cylindrical portion and forms an injection port for injecting resin. The bobbin includes a first bobbin having a first cylindrical portion, a second bobbin having a second cylindrical portion through which the first cylindrical portion is inserted, and a partition wall portion that partitions the resin filling space into a first space formed radially outside the first cylindrical portion and radially inside the second cylindrical portion and a second space formed radially outside the second cylindrical portion. The first cylindrical portion has an overlapping portion that overlaps the second cylindrical portion in the radial direction. The injection port includes a first injection port provided radially outside the first cylindrical portion, communicating with the first space, and opening radially outward, and a second injection port provided radially outside the second cylindrical portion, communicating with the second space, and opening radially outward, and is a coil component.

Advantages of the Invention

[0007] According to the coil component of the present invention, by being attached to the bobbin, the cover component forms a resin filling space between itself and the cylindrical portion and forms an injection port for injecting resin. As a result, since the core and the resin are separated by the bobbin and the cover component, the resin does not come into contact with the core. Therefore, even if the resin expands and contracts due to thermal deformation or moisture absorption of the resin, it is possible to prevent stress from being applied to the core based on the expansion and contraction of the resin. Thus, cracking of the core caused by the resin can be prevented, and the reliability of the coil component can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 7

Figure 8

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Figure 10

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Figure 14

Figure 15

Mode for Carrying Out the Invention

[0009] 〔First Embodiment〕 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. In the present embodiment, as shown in FIGS. 1 and 2, the coil component 1 is applied to the transformer 1A. The coil component 1 includes a bobbin case 2, a first winding 3, a second winding 7, a filling resin 4 (corresponding to the "resin" in the claims), a core 5, and a terminal block 8.

[0010] The bobbin case 2 is made of a material having electrical insulation properties such as hard plastic. The bobbin case 2 is formed of, for example, epoxy resin, urethane resin, silicone resin, or the like. As shown in FIG. 2, the bobbin case 2 includes a bobbin 10 and a cover component 21.

[0011] The bobbin 10 has a first bobbin 20 and a second bobbin 30. The first bobbin 20 has a cylindrical first cylinder portion 23 around which the first winding 3 is wound, a wall portion 24a disposed at the axial center of the first cylinder portion 23, and a first flange portion 24 disposed at one axial end of the first cylinder portion 23. The wall portion 24a and the first flange portion 24 each project radially outward from the outer peripheral surface of the first cylindrical portion 23. Hereinafter, the axial direction of the first cylindrical portion 23 will simply be referred to as the "axial direction", the radial direction of the first cylindrical portion 23 will simply be referred to as the "radial direction", and the circumferential direction of the first cylindrical portion 23 will simply be referred to as the "circumferential direction".

[0012] As shown in FIGS. 3 and 4, the first bobbin 20 is composed of a first bobbin constituent body 20a and a second bobbin constituent body 20b that are axially aligned and connected to each other. The first bobbin constituent body 20a has a wall portion 24a and an overlapping portion 23a that is disposed on the opposite side of the first flange portion 24 in the axial direction with respect to the wall portion 24a in the first cylindrical portion 23. A concave portion 23c that is recessed radially outward is formed in a portion of the inner peripheral surface of the overlapping portion 23a that corresponds to the wall portion 24a. The concave portion 23c is formed in an annular shape along the circumferential direction. The second bobbin constituent body 20b has a first flange portion 24 and a non-overlapping portion 23b that is disposed on the first flange portion 24 side in the axial direction with respect to the wall portion 24a in the first cylindrical portion 23. The non-overlapping portion 23b is located adjacent to the overlapping portion 23a in the axial direction. The outer diameter dimension of the non-overlapping portion 23b is smaller than the outer diameter dimension of the overlapping portion 23a. The outer diameter dimension of the non-overlapping portion 23b is equal to the inner diameter dimension of the overlapping portion 23a at the portion where the concave portion 23c is formed. The inner diameter dimension of the non-overlapping portion 23b is equal to the inner diameter dimension of the portion of the overlapping portion 23a excluding the portion where the concave portion 23c is formed. One end portion of the second bobbin constituent body 20b on the first bobbin constituent body 20a side in the non-overlapping portion 23b is inserted inside the concave portion 23c. Thereby, the second bobbin constituent body 20b is connected to the first bobbin constituent body 20a. In a state where the first bobbin constituent body 20a and the second bobbin constituent body 20b are connected, the inner peripheral surface of the non-overlapping portion 23b of the second bobbin constituent body 20b is flush with the inner peripheral surface of the overlapping portion 23a of the first bobbin constituent body 20a.

[0013] In the wall portion 24a, two guide passages 24a1 and 24a2 through which the wire of the first winding 3 passes through the wall portion 24a in the axial direction are formed at intervals in the circumferential direction. The first guide passage 24a1 is inclined in the circumferential direction with respect to the axial direction. The second guide passage 24a2 is orthogonal to the circumferential direction.

[0014] As shown in FIGS. 2 and 4, the second bobbin 30 is disposed radially outside the overlapping portion 23a of the first cylindrical portion 23. The second bobbin 30 is assembled to be axially slidable and relatively movable with respect to the first bobbin 20. The second bobbin 30 has a second cylindrical portion 31 and a second flange portion 32. The second cylindrical portion 31 is formed in a cylindrical shape. The axial length of the second cylindrical portion 31 is equal to the axial length of the first bobbin component 20a. The inner diameter dimension of the second cylindrical portion 31 is larger than the outer diameter dimension of the first cylindrical portion 23. By inserting the first cylindrical portion 23 into the second cylindrical portion 31, the second cylindrical portion 31 is coaxially disposed with the first cylindrical portion 23. The second cylindrical portion 31 is disposed so as to overlap the overlapping portion 23a of the first cylindrical portion 23 in the radial direction and not to overlap the non-overlapping portion 23b of the first cylindrical portion 23 in the radial direction. The second flange portion 32 is disposed at one end of the second cylindrical portion 31 on the side of the wall portion 24a in the axial direction. The second flange portion 32 projects radially outward from the outer peripheral surface of the second cylindrical portion 31.

[0015] The cover component 21 has an end wall portion 26 and a cover portion 27. The end wall portion 26 is provided on the side opposite to the first bobbin 20 with the second bobbin 30 interposed therebetween in the axial direction. The end wall portion 26 is formed in a plate shape with the axial direction as the thickness direction. The outer shape of the end wall portion 26 is the same as the outer shape of the first flange portion 24 when viewed from the axial direction. An insertion hole 26a penetrating the end wall portion 26 in the axial direction is formed in the end wall portion 26. The insertion hole 26a is formed in the same shape as the inner peripheral surface of the first cylindrical portion 23 when viewed from the axial direction. The insertion hole 26a communicates with the first cylindrical portion 23.

[0016] The cover portion 27 opens radially outward at a circumferential part of the outer edge of the end wall portion 26. The cover portion 27 has a first cover component 27a and a second cover component 27b arranged axially. The first cover component 27a extends axially from the outer edge of the end wall portion 26 to the outer edge of the second flange portion 32 of the second bobbin 30. Thereby, the first cover component 27a overlaps the overlapping portion 23a of the first cylindrical portion 23 and the outside of the second cylindrical portion 31 in the radial direction. The second cover component 27b is formed adjacent to the second cylindrical portion 31 axially. The second cover component 27b extends axially from the outer edge of the second flange portion 32 to the outer edge of the first flange portion 24 of the first bobbin 20. Thereby, the second cover component 27b overlaps the outside of the non-overlapping portion 23b of the first cylindrical portion 23 in the radial direction and is arranged axially with respect to the first cover component 27a. The above-described cover component 21 is attached to the bobbin 10 using, for example, an adhesive or the like. By being attached to the bobbin 10, the cover component 21 surrounds the outside of the first cylindrical portion 23 and the second cylindrical portion 31 in the radial direction. Thereby, a resin filling space S is formed between the first cylindrical portion 23 and the second cylindrical portion 31 and the cover component 21. The resin filling space S is filled with a filling resin 4 having electrical insulation properties. The opening of the cover portion 27 formed at a circumferential part of the outer edge of the end wall portion 26 serves as an injection port 2a formed in the bobbin case 2. The injection port 2a is for injecting the filling resin 4 into the resin filling space S. The injection port 2a opens to the outside in the radial direction of the first cylindrical portion 23.

[0017] The first winding 3 is an input-side primary winding connected to a power circuit (not shown). The first winding 3 is formed by winding a wire around the outer peripheral surface of the first cylindrical portion 23 in its circumferential direction. That is, the first winding 3 is formed in a cylindrical shape by being wound around the core 5 via the first bobbin 20. The wire of the first winding 3 is a litz wire in which a plurality of enameled wires are twisted together. The first winding 3 is covered from the outside by the cover component 21. Both ends 3a of the wire of the first winding 3 are drawn out to the outside of the bobbin case 2 from the injection port 2a. The second winding 7 is a secondary winding on the output side connected to a load device (not shown). The second winding 7 is formed by winding a wire around the outer peripheral surface of the second cylindrical portion 31 in its circumferential direction. That is, the second winding 7 is formed in a cylindrical shape by being wound around the core 5 via the second bobbin 30. A second cylindrical portion 31 is interposed between the second winding 7 and the first winding 3. Thereby, the second winding 7 is wound outside the first winding 3 in the radial direction while being insulated from the first winding 3 by the second bobbin 30. The wire of the second winding 7 is a Litz wire in which a plurality of enameled wires are twisted together. The wire diameter of the wire of the second winding 7 is larger than the wire diameter of the wire of the first winding 3. The second winding 7 is covered from the outside by a cover component 21. Both end portions 7a of the wire of the second winding 7 are drawn out to the outside of the bobbin case 2 from the injection port 2a.

[0018] The core 5 is a member made of a magnetic material such as ferrite, for example. As shown in FIG. 2, the core 5 is formed by two core pieces 50. Since the two core pieces 50 are substantially the same, only one of the core pieces 50 will be described. The core piece 50 has an inner piece 51 formed in a columnar shape, two outer pieces 52 disposed on both sides in the radial direction with respect to the inner piece 51, and a connecting piece 53 that connects the two outer pieces 52 in the radial direction.

[0019] The axial length of the inner piece 51 is longer in the core piece 50 on the first bobbin 20 side among the two core pieces 50. Each of the two outer pieces 52 is formed in a rectangular plate shape in which the thickness direction coincides with the direction orthogonal to the opening direction of the injection port 2a in the radial direction. The two outer pieces 52 are spaced apart on both sides of the inner piece 51 in the radial direction. The axial length of the outer piece 52 is longer in the core piece 50 on the first bobbin 20 side among the two core pieces 50. The connecting piece 53 is formed in a rectangular plate shape with its thickness direction coinciding with the axial direction. The axial end of the inner piece 51 is continuous with the connecting piece 53. A recess 53a is formed in the end face of the connecting piece 53 on the side where the injection port 2a opens. The recess 53a is formed in a tapered shape that widens from its bottom 53a2 toward the end face of the connecting piece 53 where the recess 53a opens. The recess 53a has a flat bottom 53a2 and two flat side portions 53a1 that extend obliquely from both sides of the bottom 53a2 to the end face of the connecting piece 53.

[0020] The above-described core piece 50 is formed in an E shape when viewed from the opening direction of the injection port 2a. The two core pieces 50 are attached to the bobbin case 2 by inserting their respective inner pieces 51 into the inside of the first cylindrical portion 23 of the bobbin case 2 from opposite sides in the axial direction. The inner pieces 51 of the two core pieces 50 inserted into the inside of the first cylindrical portion 23 are spaced apart in the axial direction inside the first cylindrical portion 23. In a state where the two core pieces 50 are attached to the two bobbin cases 2, the tips of the outer pieces 52 of the two core pieces 50 abut against each other. The abutting outer pieces 52 of the two core pieces 50 are fixed, for example, by adhesion or the like. In a state where the two core pieces 50 are attached to the bobbin case 2, the connecting pieces 53 of the two core pieces 50 are arranged so as to sandwich the bobbin case 2 in the axial direction. The core 5 attached to the bobbin case 2 is isolated from the resin filling space S by the bobbin case 2.

[0021] The terminal blocks 8 are provided one by one on the end wall portion 26 of the cover component 21 and the first flange portion 24 of the first bobbin 20. The terminal blocks 8 are provided at the ends in the opening direction of the injection port 2a in the end wall portion 26 and the first flange portion 24. The terminal block 8 includes a terminal block main body 8a and a pedestal 8b. Only the terminal block 8 on the side of the end wall portion 26 among the two terminal blocks 8 will be described. Since the terminal block 8 on the side of the first flange portion 24 has the same configuration as the terminal block 8 on the side of the end wall portion 26, the description thereof will be omitted. The terminal block 8 is integrally formed with the end wall portion 26. The terminal block main body 8a projects axially outward from the end wall portion 26. The terminal block main body 8a extends in a direction orthogonal to the axial direction and the opening direction of the injection port 2a. The end face of the terminal block main body 8a on the side opposite to the opening direction of the injection port 2a is along the recess 53a. Thereby, the terminal block main body 8a is fitted into the recess 53a. The pedestal 8b is a rectangular plate-shaped member provided at both longitudinal ends of the terminal block main body 8a. The thickness direction of the pedestal 8b coincides with the opening direction of the injection port 2a. The pedestal 8b is placed on the end face of the connecting piece 53 on the side where the recess 53a opens. A nut placement portion 8c for arranging a hexagonal nut is formed on the pedestal 8b. The nut placement portion 8c is a recess formed in a hexagonal shape when viewed from the side opposite to the opening direction of the injection port 2a. Each pedestal 8b has a terminal 9 attached thereto.

[0022] The terminal 9 is formed of a metal material such as copper, for example. The terminal 9 has a terminal main body 9a and a support portion 9b. The terminal main body 9a is formed in a rectangular plate shape with the thickness direction coinciding with the opening direction of the injection port 2a. The terminal main body 9a is placed on the pedestal 8b. The terminal main body 9a has a claw portion extending toward the pedestal 8b side and is fixed to the pedestal 8b by snap fitting by the claw portion. A through hole 9c penetrating the terminal main body 9a in the thickness direction is provided in the terminal main body 9a. A hexagonal nut is arranged between the terminal main body 9a and the pedestal 8b. The hexagonal nut is non-rotatably arranged within the nut placement portion 8c of the pedestal 8b. A terminal (not shown) of an external power circuit is connected to the terminal main body 9a, for example, by bolt fastening. The support portion 9b is provided inside a pair of terminal main bodies 9a. The support portion 9b extends along the axial direction. The axially outer end of the support portion 9b is located axially outside the terminal main body 9a. The axially outer end of the support portion 9b is formed in a U shape that opens inward in the facing direction of the pair of terminal main bodies 9a when viewed from the axial direction. Inside the axially outer end of the support portion 9b, the end portions 3a, 7a of the wire rods constituting the windings 3, 7 are arranged. The end portions 3a, 7a are fixed to the support portion 9b by, for example, welding in a state of being clamped to the axially outer end of the support portion 9b.

[0023] Here, with reference to FIGS. 2 and 4, an example of the method for assembling the transformer 1A will be described. To assemble the transformer 1A, first, a wire is wound around the non-overlapping portion 23b of the first cylindrical portion 23 in three layers, and the wire is wound around the overlapping portion 23a of the first cylindrical portion 23 in one layer to form the first winding 3. Note that the number of winding layers of the first winding 3 can be appropriately changed.

[0024] Subsequently, a wire is wound around the outer peripheral surface of the second cylindrical portion 31 of the second bobbin 30 in one layer to form the second winding 7. Note that the number of winding layers of the second winding 7 can be appropriately changed. Subsequently, the overlapping portion 23a of the first cylindrical portion 23 is inserted into the second cylindrical portion 31, and the first bobbin 20 and the second bobbin 30 are assembled so that the first cylindrical portion 23 and the second cylindrical portion 31 are coaxial. In the state where the first bobbin 20 and the second bobbin 30 are assembled, the non-overlapping portion 23b of the first cylindrical portion 23 is covered by the second cover member 27b. The assembled first bobbin 20 and the second bobbin 30 are joined with an adhesive.

[0025] Subsequently, the overlapping portion 23a of the first cylindrical portion 23 of the first bobbin 20 and the second cylindrical portion 31 of the second bobbin 30 are inserted inside the first cover member 27a of the cover component 21, and the cover component 21, the first bobbin 20, and the second bobbin 30 are assembled so that the insertion hole 26a of the cover component 21 and the first cylindrical portion 23 and the second cylindrical portion 31 are coaxial. The cover component 21 and the second bobbin 30 are joined with an adhesive. Thereby, the bobbin case 2 is formed. Thereafter, the resin 4 is injected into the resin filling space S from the injection port 2a of the bobbin case 2. Thereby, the first winding 3 and the second winding 7 are covered by the resin 4. After the resin 4 is solidified, the inner piece 51 of the two core pieces 50 constituting the core 5 is inserted into the first cylindrical portion 23. The outer pieces 52 of the two core pieces 50 are joined with an adhesive to attach the core 5 to the bobbin case 2. In this way, the transformer 1A is assembled.

[0026] In transformer 1A, the electrical coupling between the first winding 3 and the second winding 7 is dense at the overlapping portion 23a and sparse at the non-overlapping portion 23b. Therefore, the leakage inductance generated between the first winding 3 and the second winding 7 becomes small at the overlapping portion 23a and large at the non-overlapping portion 23b. For this reason, by adjusting the number of turns of the first winding 3 at the non-overlapping portion 23b, the leakage inductance can be changed and adjusted to an appropriate value. Also, by changing the relative positional relationship between the first winding 3 and the second winding 7, the number of turns of the first winding 3 and the second winding 7 at the overlapping portion 23a, the wire diameters of the first winding 3 and the second winding 7, etc., the leakage inductance can be changed and adjusted to an appropriate value.

[0027] As described above, according to the coil component 1 according to the first embodiment, the cover component 21 is attached to the bobbin 10, thereby forming a resin filling space S between the cylindrical portions 23 and 31 and forming an injection port 2a for injecting the filling resin 4. As a result, since the core 5 and the filling resin 4 are isolated by the bobbin 10 and the cover component 21, the filling resin 4 does not touch the core 5. Therefore, even if the filling resin 4 expands and contracts due to thermal deformation or moisture absorption of the filling resin 4, it is possible to prevent stress from being applied to the core 5 based on the expansion and contraction of the filling resin 4. Therefore, it is possible to prevent cracking of the core 5 caused by the filling resin 4 and improve the reliability of the coil component 1.

[0028] In the first embodiment, the first cylindrical portion 23 has an overlapping portion 23a that overlaps the second cylindrical portion 31 in the radial direction, and a non-overlapping portion 23b that is located adjacent to the overlapping portion 23a in the axial direction and does not overlap the second cylindrical portion 31 in the radial direction. Thereby, by adjusting the ratio between the overlapping portion 23a and the non-overlapping portion 23b in the first cylindrical portion 23, the density of the electrical coupling and the leakage inductance between the first winding 3 and the second winding 7 can be adjusted. Therefore, it is possible to provide a coil component 1 with excellent versatility that can freely adjust the leakage inductance.

[0029] In the first embodiment, the cover component 21 has a first cover structure body 27a that overlaps the outside of the second cylindrical portion 31 in the radial direction, and a second cover structure body 27b that is formed adjacent to the second cylindrical portion 31 in the axial direction, overlaps the outside of the first cylindrical portion 23 in the radial direction, and is arranged axially with respect to the first cover structure body 27a. Thereby, after the first winding 3 is wound around the first cylindrical portion 23, the second cover structure body 27b can be arranged radially outside the first cylindrical portion 23, and after the second winding 7 is wound around the second cylindrical portion 31, the first cover structure body 27a can be arranged radially outside the second cylindrical portion 31. Therefore, the first winding 3 can be easily wound around the first cylindrical portion 23, and the second winding 7 can be easily wound around the second cylindrical portion 31.

[0030] In the first embodiment, the first winding 3 and the second winding 7 are covered with a filled resin 4 filled in the resin filling space S. For this reason, the heat generated in the first winding 3 and the second winding 7 due to energization can be dissipated to the filled resin 4 and the bobbin case 2, and the temperature rise of the first winding 3 and the second winding 7 can be suppressed.

[0031] In the first embodiment, compared with a conventional coil component that covers both the windings 3, 7 and the core 5 with resin, the amount of the filled resin 4 used is reduced, so that the coil component 1 can be made lighter and smaller.

[0032] In the first embodiment, the first winding 3 and the second winding 7 may be pre-formed in a cylindrical shape in a state before being attached to the first cylindrical portion 23 and the second cylindrical portion 31, respectively. That is, the cylindrically formed first winding 3 may be attached to the first cylindrical portion 23, and the cylindrically formed second winding 7 may be attached to the second cylindrical portion 31.

[0033] Next, with reference to FIGS. 5 to 12, four modified examples of the coil component 1 described above will be described.

[0034] A first modified example of the coil component 1 will be described. In the first modified example, the same reference numerals are given to the same components as those in the first embodiment described above, and the description thereof will be omitted. Figures 5 and 6 show a first modified example of the coil component 1 (transformer 1A). In the coil component 1 of the first modified example, the terminal block 8 and the terminal 9 are not provided.

[0035] The first bobbin 20 has a third flange portion 25 disposed at the other end of the first cylindrical portion 23 in the axial direction, opposite to the first flange portion 24. The second bobbin 30 has a fourth flange portion 33 disposed at the other end of the second cylindrical portion 31 in the axial direction, opposite to the second flange portion 32. The second cylindrical portion 31 and the second flange portion 32 of the second bobbin 30 constitute a partition wall portion 34.

[0036] The partition wall portion 34 divides the resin filling space S into a first space S1 formed radially outside the first cylindrical portion 23 and a second space S2 formed radially outside the second cylindrical portion 31. A part of the first space S1 is covered radially outward by the second cylindrical portion 31 of the partition wall portion 34. The first winding 3 is disposed in the first space S1. The second winding 7 is disposed in the second space S2.

[0037] Unlike the first embodiment, the cover portion 27 is not divided into a first cover constituent body 27a and a second cover constituent body 27b (see FIG. 2). The cover portion 27 is provided on the cover component 21 and extends axially from the end wall portion 26 of the cover component 21 to the outer edge of the first flange portion 24 of the first bobbin 20. Thus, the first cylindrical portion 23, the second cylindrical portion 31, and the cover portion 27 are constituted by separate components (the first bobbin 20, the second bobbin 30, and the cover component 21).

[0038] The inlet 2a of the bobbin case 2 is partitioned by the partition wall portion 34 into a first inlet 2a1 for injecting the filling resin 4 into the first space S1 and a second inlet 2a2 for injecting the filling resin 4 into the second space S2. The first inlet 2a1 and the second inlet 2a2 open to the outside in the radial direction of the first cylindrical portion 23 and the second cylindrical portion 31, respectively, and are arranged axially. The first inlet 2a1 communicates with the first space S1. From the first inlet 2a1, the end portion 3a of the wire of the first winding 3 is drawn out to the outside of the coil component 1. The second inlet 2a2 communicates with the second space S2. From the second inlet 2a2, the end portion 7a of the wire of the second winding 7 is drawn out to the outside of the coil component 1.

[0039] In the first modification, the bobbin 10 includes a partition wall portion 34 that partitions the resin filling space S into a first space S1 formed radially outside the first cylindrical portion 23 and a second space S2 formed radially outside the second cylindrical portion 31. Thereby, the first winding 3 and the second winding 7 can be covered with different filling resins 4, respectively. Specifically, the first winding 3 and the second winding 7 can be covered with filling resins 4 having different thermal conductivities, respectively. For example, a filling resin 4 having a high thermal conductivity can be injected into the space in which the winding with a large heat generation is arranged among the first space S1 and the second space S2. In this case, compared with the case where the resin filling space S is not partitioned into the first space S1 and the second space S2 and only the filling resin 4 having a high thermal conductivity is injected into the resin filling space S, the amount of the filling resin 4 having a high thermal conductivity used can be reduced. Generally, since the filling resin 4 having a high thermal conductivity has a higher cost than the resin having a low thermal conductivity, the manufacturing cost of the coil component 1 can be reduced by reducing the amount of the filling resin 4 having a high thermal conductivity used.

[0040] In the first modification, the inlet 2a has a first inlet 2a1 communicating with the first space S1 and a second inlet 2a2 communicating with the second space S2. This is suitable for injecting different filling resins 4 into the first space S1 and the second space S2, respectively.

[0041] In the first modification example, the first cylindrical portion 23, the second cylindrical portion 31, and the cover portion 27 are constituted by separate components (the first bobbin 20, the second bobbin 30, and the cover component 21). As a result, after assembling the first bobbin 20 and the second bobbin 30, the radially outer sides of the first bobbin 20 and the second bobbin 30 can be covered with the cover portion 27. Therefore, after assembling the first bobbin 20 and the second bobbin 30, the number of turns of the first winding 3 and the second winding 7 can be adjusted to adjust the leakage inductance. After adjusting the leakage inductance, the cover portion 27 can be assembled to the first bobbin 20 and the second bobbin 30. Thus, a coil component 1 excellent in versatility capable of freely adjusting the leakage inductance can be provided.

[0042] In the first modification example, the first injection port 2a1 and the second injection port 2a2 open to the radially outer sides of the first cylindrical portion 23 and the second cylindrical portion 31, respectively. As a result, the end portion 3a of the wire material of the first winding 3 wound around the first cylindrical portion 23 can be easily drawn out to the outside of the bobbin 10 from the first injection port 2a1, and the end portion 7a of the wire material of the second winding 7 wound around the second cylindrical portion 31 can be easily drawn out to the outside of the bobbin 10 from the second injection port 2a2. That is, the first injection port 2a1 also functions as an outlet for the end portion 3a of the wire material of the first winding 3, and the second injection port 2a2 also functions as an outlet for the end portion 7a of the wire material of the second winding 7. Thereby, in one step, the filling resin 4 can be injected into the first space S1, and the end portion 3a of the wire material of the first winding 3 can be fixed in a state of being drawn out from the first injection port 2a1. Also, in one step, the filling resin 4 can be injected into the second space S2, and the end portion 7a of the wire material of the second winding 7 can be fixed in a state of being drawn out from the second injection port 2a2. Therefore, the coil component 1 can be efficiently manufactured.

[0043] A second modification example of the coil component 1 will be described. In the second modification example, the same reference numerals are given to the same components as those in the above-described first embodiment and the first modification example, and the description thereof is omitted. Figures 7 and 8 show a second modified example of the coil component 1 (transformer 1A). In the second modified example, the axial length of the second cylindrical portion 31 is equal to the axial length of the first cylindrical portion 23. For this reason, the axial length of the second winding 7 wound around the second cylindrical portion 31 becomes equal to the axial length of the first winding 3 wound around the first cylindrical portion 23. That is, in a state where the first cylindrical portion 23 is inserted inside the second cylindrical portion 31, the entire first winding 3 and the first cylindrical portion 23 in the axial direction overlap the second winding 7 and the second cylindrical portion 31 in the radial direction, respectively. The fourth flange portion 33 of the second bobbin 30 is formed in the same shape as the second flange portion 32 of the second bobbin 30 when viewed from the axial direction. The partition wall portion 34 is constituted by the second cylindrical portion 31, the second flange portion 32, and the fourth flange portion 33 of the second bobbin 30.

[0044] A first bulging portion 28 is formed on the first flange portion 24 of the first bobbin 20. The first bulging portion 28 is formed on the outer edge portion of the first flange portion 24 located on the injection port 2a side. The first bulging portion 28 is formed so as to bulge outward from the first flange portion 24 to the outside of the bobbin case 2 in the axial direction. The outer shape of the first bulging portion 28 is formed in substantially the same shape as the concave portion 53a of the connecting piece 53 when viewed from the axial direction. When the transformer 1A is assembled, the first bulging portion 28 enters the concave portion 53a, and the axial end surface of the first bulging portion 28 becomes flush with the end surface of the connecting piece 53 orthogonal to the axial direction. In a state where the transformer 1A is assembled, the first bulging portion 28 constitutes a first passage portion 28a that opens radially outward on the first flange portion 24 side in the axial direction of the first space S1 covered by the second cylindrical portion 31. The first passage portion 28a constitutes a part of the first injection port 2a1.

[0045] On the end wall portion 26 of the cover component 21, a second bulging portion 29 is formed. The second bulging portion 29 is formed at the outer edge portion of the end wall portion 26 located on the injection port 2a side. The second bulging portion 29 is formed so as to bulge outward from the end wall portion 26 to the outside of the bobbin case 2 in the axial direction. The outer shape of the second bulging portion 29 is formed to be substantially the same shape as the concave portion 53a of the connecting piece 53 when viewed from the axial direction. When the transformer 1A is assembled, the second bulging portion 29 enters the concave portion 53a, and the axial end surface of the second bulging portion 29 is flush with the end surface of the connecting piece 53 perpendicular to the axial direction. In the state where the transformer 1A is assembled, the second bulging portion 29 constitutes a second passage portion 29a that opens radially outward on the end wall portion 26 side in the axial direction of the second cylindrical portion 31 for the first space S1 covered by the second cylindrical portion 31. The second passage portion 29a constitutes a part of the first injection port 2a1. A pair of first injection ports 2a1 are provided on both outer sides in the axial direction rather than the second cylindrical portion 31 and open radially outside the second cylindrical portion 31.

[0046] The first winding 3 is wound around the outer peripheral surface of the first cylindrical portion 23 in one layer. Both end portions 3a of the wire material of the first winding 3 are respectively drawn out from the first passage portion 28a and the second passage portion 29a to the outside of the transformer 1A.

[0047] In the second modification, the first injection ports 2a1 are provided on both outer sides in the axial direction rather than the second cylindrical portion 31 and open radially outside the second cylindrical portion 31. Thereby, even if the entire first cylindrical portion 23 is covered by the second cylindrical portion 31, the filling resin 4 can be injected into the first space S1 through the first injection ports 2a1. Further, by injecting the filling resin 4 into the first space S1 from one of the first injection ports 2a1, the air in the first space S1 can be discharged to the outside of the coil component 1 from the other first injection port 2a1. Thereby, it is possible to suppress the remaining of air bubbles (voids) in the filling resin 4 filled in the first space S1.

[0048] In the second modification example, the first injection port 2a1 that opens the first space S1 covered by the second cylindrical portion 31 to the radially outer side is not limited to being formed outside the second cylindrical portion 31 in the axial direction. For example, it may be configured by a pipe portion that extends radially outward from the outer peripheral surface of the second cylindrical portion 31 and communicates with the inside of the second cylindrical portion 31. In the configuration in which the pipe portion is provided in the second cylindrical portion 31, the filling resin 4 can be injected from the opening on the radially outer side of the pipe portion into the inside of the second cylindrical portion 31, that is, the first space S1.

[0049] A third modification example of the coil component 1 will be described. In the third modification example, the same reference numerals are given to the same components as in the above-described first embodiment and each modification example, and the description thereof is omitted. FIGS. 9 and 10 show a third modification example of the coil component 1 (transformer 1A). In the third modification example, the second bobbin 30 is formed in substantially the same shape as the first bobbin 20. That is, the shapes of the second cylindrical portion 31, the second flange portion 32, and the fourth flange portion 33 of the second bobbin 30 are substantially the same as the shapes of the first cylindrical portion 23, the first flange portion 24, and the third flange portion 25 of the first bobbin 20, respectively. The second cylindrical portion 31 of the second bobbin 30 is located adjacent to the first cylindrical portion 23 of the first bobbin 20 in the axial direction. The second cylindrical portion 31 is coaxial with the first cylindrical portion 23.

[0050] The partition wall portion 34 is constituted by the second flange portion 32 of the second cylindrical portion 31. The partition wall portion 34 divides the resin filling space S of the bobbin case 2 into a first space S1 and a second space S2 arranged in the axial direction.

[0051] The first winding 3 is wound around the outer peripheral surface of the first cylindrical portion 23 in three layers. The second winding 7 is wound around the outer peripheral surface of the second cylindrical portion 31 in three layers. The second winding 7 is arranged axially aligned with the first winding 3. The second winding 7 has the same axial and radial lengths as the first winding 3. The wire diameter of the wire of the second winding 7 is the same as the wire diameter of the wire of the first winding 3.

[0052] In the third modification example, the bobbin 10 includes a first bobbin 20 having a first cylindrical portion 23 and a second bobbin 30 having a second cylindrical portion 31 positioned adjacent to the first cylindrical portion 23 in the axial direction. Thereby, by adjusting the axial gap between the first winding 3 and the second winding 7, the closeness of the electrical coupling and the leakage inductance between the first winding 3 and the second winding 7 can be adjusted. Therefore, it is possible to provide the coil component 1 excellent in versatility capable of freely adjusting the leakage inductance.

[0053] A fourth modification example of the coil component 1 will be described. In the fourth modification example, the same components as those in the first embodiment and each modification example described above are denoted by the same reference numerals, and the description thereof will be omitted. FIGS. 11 and 12 show a fourth modification example of the coil component 1 (transformer 1A). In the fourth modification example, the second bobbin 30 does not have the second flange portion 32 and the fourth flange portion 33 (see FIGS. 5 and 6), and is composed only of the second cylindrical portion 31. Therefore, unlike the second embodiment, the resin filling space S is not partitioned into the first space S1 and the second space S2 (see FIG. 6).

[0054] In the fourth modification example, the second bobbin 30 is composed only of the second cylindrical portion 31. Thereby, even when the first bobbin 20 is inserted into the second bobbin 30, the filling resin 4 can be easily injected into the entire resin filling space S. Therefore, the coil component 1 can be efficiently manufactured.

[0055] 〔Second Embodiment〕 Next, a second embodiment of the present invention will be described with reference to FIGS. 13 to 15. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0056] As shown in FIGS. 13 to 15, the coil component 1 of the present embodiment has the same configuration as the coil component 1 of the first embodiment, but is different from the coil component 1 of the first embodiment in the following points.

[0057] The bobbin 10 is composed of the first bobbin 20. The bobbin case 2 includes a fixing portion 22 in addition to the first bobbin 20 and the cover component 21. The fixing portion 22 has a first fixing portion 22a and a second fixing portion 22b. The first fixing portion 22a is provided at an end of the first flange portion 24 of the first bobbin 20 on the side opposite to the inlet 2a in the radial direction. The first fixing portion 22a is a rectangular plate-like member extending axially on the side opposite to the first cylindrical portion 23. Two first fixing portions 22a are provided spaced apart in a direction orthogonal to the axial direction. The second fixing portion 22b is provided at an end of the end wall portion 26 of the cover component 21 on the side opposite to the inlet 2a in the radial direction. The second fixing portion 22b is a rectangular plate-like member extending axially toward the side opposite to the first cylindrical portion 23. Two second fixing portions 22b are provided spaced apart in a direction orthogonal to the axial direction, similarly to the first fixing portion 22a. The first fixing portion 22a and the second fixing portion 22b are each bolted to the heat dissipation member 6. Thereby, the bobbin case 2 is in close contact with the heat dissipation member 6.

[0058] Here, with reference to FIGS. 14 and 15, an example of the method of assembling the coil component 1 will be described. To assemble the coil component 1, first, a wire is wound around the outer peripheral surface of the first cylindrical portion 23 in three layers between the first flange portion 24 and the third flange portion 25 of the first bobbin 20 to form a first winding 3. Note that the number of winding layers of the first winding 3 can be changed as appropriate.

[0059] Subsequently, the first cylindrical portion 23 of the first bobbin 20 is inserted inside the cover portion 27 of the cover component 21, and the cover component 21 is assembled to the first bobbin 20 such that the insertion hole 26a in the end wall portion 26 of the cover component 21 and the first cylindrical portion 23 of the first bobbin 20 are coaxial. The cover component 21 and the first bobbin 20 are joined with an adhesive. Thereby, the bobbin case 2 is formed. Thereafter, the filling resin 4 is injected into the resin filling space S from the injection port 2a of the bobbin case 2. Thereby, the first winding 3 is covered with the filling resin 4. After the filling resin 4 has solidified, the inner piece 51 of the two core pieces 50 constituting the core 5 is inserted inside the first cylindrical portion 23, and the outer pieces 52 of the two core pieces 50 are joined with an adhesive, thereby attaching the core 5 to the bobbin case 2. In this way, the coil component 1 is assembled. The coil component 1 is attached by being bolted to the heat dissipation member 6 at the fixing portion 22. In the above-described method for assembling the coil component 1, the attachment of the core 5 to the bobbin case 2 may be, for example, after the bobbin case 2 is formed and before the filling resin 4 is injected into the resin filling space S.

[0060] In the second embodiment, the bobbin case 2 is made of a material having electrical insulation properties and has a fixing portion 22 for bringing the bobbin case 2 into close contact with the heat dissipation member 6. Therefore, even if the heat dissipation member 6 has conductivity such as an aluminum block or the like, the bobbin case 2 can be brought into direct close contact with the heat dissipation member 6 without separately interposing an insulating member therebetween.

[0061] As described above, the embodiments according to the present invention have been described. However, the present invention is not limited to the above-described embodiments and modifications, and various changes can be made without departing from the gist of the present invention. For example, in the transformer 1A, the first winding 3 may be used as the secondary winding and the second winding 7 may be used as the primary winding. Also, the wire diameter of the wire material of the second winding 7 may be larger or smaller than the wire diameter of the wire material of the first winding 3.

[0062] In the present invention, the transformer 1A may not include the second bobbin 30. For example, an insulating tape may be wound around the outer peripheral surface of the first winding 3, and the second winding 7 may be wound on top of the insulating tape. In the present invention, the injection port 2a may open not only in the radial direction but also in the axial direction. That is, the filling resin 4 may be injected into the resin filling space S of the bobbin case 2 from the axial direction.

[0063] The coil component of the present invention may be applied to a choke coil or the like. The coil component 1 only needs to include at least a bobbin case 2, a first winding 3, a filling resin 4, and a core 5. The bobbin case 2 only needs to have at least a first bobbin 20 and a cover component 21.

Explanation of Reference Numerals

[0064] 1 Coil component 2a Injection port 2a1 First injection port 2a2 Second injection port 3 First winding (winding) 4 Resin (filling resin) 7 Second winding (winding) 10 Bobbin 20 First bobbin 21 Cover component 23 First cylindrical part (cylindrical part) 23a Overlapping part 23b Non - overlapping part 27a First cover structure 27b Second cover structure 30 Second bobbin 31 Second cylindrical part (cylindrical part) 34 Partition wall part S Resin filling space S1 First space S2 Second space

Claims

1. A bobbin having a cylindrical portion, A winding wound around the cylindrical portion, A cover component attached to the bobbin and covering the winding from the outside, Comprising: By being attached to the bobbin, the cover component forms a resin filling space between the cover component and the cylindrical portion, and forms an injection port for injecting resin. The bobbin: A first bobbin having a first cylindrical portion, A second bobbin having a second cylindrical portion through which the first cylindrical portion is inserted, Having: The first cylindrical portion: An overlapping portion that overlaps the second cylindrical portion in the radial direction, A non-overlapping portion that is located adjacent to the overlapping portion in the axial direction and does not overlap the second cylindrical portion in the radial direction, Having: The cover component: A first cover structure that overlaps the outside of the second cylindrical portion in the radial direction, A coil component having a second cover structure that is formed adjacent to the second cylindrical portion in the axial direction, overlaps the outside of the first cylindrical portion in the radial direction, and is arranged axially with respect to the first cover structure.

2. A bobbin having a cylindrical portion, A winding wound around the cylindrical portion, A cover component attached to the bobbin and covering the winding from the outside, Comprising: By being attached to the bobbin, the cover component forms a resin filling space between the cover component and the cylindrical portion, and forms an injection port for injecting resin. The bobbin: A first bobbin having a first cylindrical portion, A second bobbin having a second cylindrical portion located adjacent to the first cylindrical portion in the axial direction, Having: The cover component: A first cover structure that overlaps the outside of the second cylindrical portion in the radial direction, A coil component having a second cover structure that is formed adjacent to the second cylindrical portion in the axial direction, overlaps the outside of the first cylindrical portion in the radial direction, and is arranged axially with respect to the first cover structure.

3. The coil component according to claim 1 or claim 2, wherein the bobbin includes a partition wall portion that partitions the resin filling space into a first space formed radially outside the first cylindrical portion and a second space formed radially outside the second cylindrical portion.

4. A bobbin having a cylindrical portion, A winding wound around the cylindrical portion, A cover component attached to the bobbin and covering the winding from the outside, Comprising: By being attached to the bobbin, the cover component forms a resin filling space between the cover component and the cylindrical portion, and forms an injection port for injecting resin. The bobbin: A first bobbin having a first cylindrical portion, A second bobbin having a second cylindrical portion through which the first cylindrical portion is inserted; A partition wall portion that partitions the resin filling space into a first space formed radially outside the first cylindrical portion and radially inside the second cylindrical portion, and a second space formed radially outside the second cylindrical portion; having; The first cylindrical portion has an overlapping portion that overlaps the second cylindrical portion in the radial direction; The injection port is; a first injection port provided radially outside the first cylindrical portion, communicating with the first space, and opening radially outward; a second injection port provided radially outside the second cylindrical portion, communicating with the second space, and opening radially outward; a coil component having.

5. The coil component according to claim 4, wherein a pair of the first injection ports are provided on both outer sides in the axial direction of the second cylindrical portion and open radially outside the second cylindrical portion.

Images