JP2017162867A - Coil, transformer, and method of manufacturing coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil which is excellent in heat dissipation while securing insulation property.SOLUTION: Disclosed is a coil 10 which is equipped with a wound winding and in which a hollow part is formed. This coil includes a resin layer formed by resin having heat dissipation and insulation property and covering the whole surface of the wound winding. The resin layer includes; a first resin layer 5 covering the outer peripheral surface of the wound winding and a second resin layer 8 covering surfaces (inner peripheral surface, upper surface, and bottom surface) except the outer peripheral surface.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a coil, a transformer, and a method for manufacturing a coil.

  For example, Patent Document 1 discloses a coil including a cylindrical bobbin and a winding wound along the outer periphery thereof as a coil used in a transformer.

JP 2003-92221 A

  The coil used for the transformer is required to have heat dissipation as well as insulation. However, although the coil currently disclosed by patent document 1 has ensured insulation using the cylindrical bobbin, heat dissipation is not considered.

  An object of the present invention is to provide a coil, a transformer, and a method of manufacturing a coil that are excellent in heat dissipation while ensuring insulation.

  A coil according to one embodiment of the present invention includes a wound winding and is a coil in which a hollow portion is formed, and is formed of a resin having heat dissipation properties and insulating properties. A resin layer covering the entire surface is provided.

  A transformer according to an aspect of the present invention includes a plurality of the coils, and a core on which a middle leg is inserted through each insertion hole of the plurality of coils, and the plurality of coils includes one primary side. A coil and at least one secondary coil.

  The method for manufacturing a coil according to one aspect of the present invention includes: winding a winding to create a first intermediate molded body having a hollow portion; and the first intermediate molded body formed on the first molded member. The first intermediate molded body is accommodated in a through-hole having a diameter larger than the outer diameter, and the space between the outer peripheral surface of the first intermediate molded body and the wall surface along the through-hole has heat dissipation and insulating properties. A second intermediate molded body having a first resin layer that covers the outer peripheral surface of the first intermediate molded body is formed by injecting resin, and the second intermediate molded body formed on the second molded member. The second intermediate molded body is accommodated in a recess having substantially the same shape as the outer shape, the resin is injected into a space between the second intermediate molded body and a surface other than the outer peripheral surface, and other than the outer peripheral surface of the molded body. A coil having a second resin layer covering the surface is created.

  According to the present invention, it is possible to provide a coil, a transformer, and a method for manufacturing a coil excellent in heat dissipation while ensuring insulation.

Explanatory drawing of the first formability process The perspective view which shows a 1st intermediate molded object A-A cross-sectional view of FIG. A perspective view and a top view showing the second intermediate molded body Explanatory drawing of the second molding process BB sectional view of FIG. The perspective view, side view, and top view which show the coil which concerns on embodiment of this invention 1 is an exploded perspective view showing an example of a transformer according to an embodiment of the present invention. The perspective view which shows the whole structure of an example of the transformer which concerns on embodiment of this invention The perspective view which shows the whole structure of an example of the transformer which concerns on embodiment of this invention The perspective view which shows an example at the time of taking out the coil which concerns on embodiment of this invention

  Embodiments of the present invention will be described below with reference to the drawings.

  A coil and a manufacturing method thereof according to an embodiment of the present invention will be described. The coil manufacturing method of the present embodiment includes a first molding step and a second molding step. The second molding process is performed after the first molding process.

  Hereinafter, the first molding process will be described with reference to FIG. FIG. 1 is an explanatory diagram of the first molding step.

  First, as shown in FIG. 1A, the winding 2 is wound around the protrusion 1 b of the mold 1 in a solenoid shape. The mold 1 has a flat plate 1a and a protruding portion 1b. The protrusion 1b has a columnar shape and is provided at the center of the flat plate 1a. The cross section of the protrusion 1b is, for example, a perfect circle. The winding 2 is a litz wire, for example, and is wound along the outer peripheral surface of the protrusion 1b. By this winding, the first intermediate molded body 10a is formed.

  Here, the first intermediate molded body 10a will be described with reference to FIG. FIG. 2 is a perspective view showing the first intermediate molded body 10a.

  As shown in FIG. 2, the 1st intermediate molded object 10a is comprised by the coil | winding 2 wound twice. An insertion hole 2a (an example of a hollow portion) having a columnar shape (the same shape as the protruding portion 1b) is formed in the central portion of the first intermediate molded body 10a. For example, a middle leg 12 (see FIG. 8) of a core 30 described later is inserted into the insertion hole 2a.

  In FIG. 2, d1 represents the inner diameter of the first intermediate molded body 10a (also referred to as the diameter of the insertion hole 2a). Moreover, d2 has shown the outer diameter of the 1st intermediate molded object 10a. Moreover, h1 has shown the height of the 1st intermediate molded object 10a.

  In the present embodiment, in the first intermediate molded body 10a shown in FIG. 2, f1 is defined as the outer peripheral surface, f2 is defined as the inner peripheral surface, and f3 is defined as the upper surface. Although illustration is omitted, a surface opposite to the upper surface f3 is defined as a bottom surface f4 (see FIG. 3). These definitions also apply to the second intermediate molded body 10b described later.

  The first intermediate molded body 10a has been described above. Hereinafter, the description returns to the first molding step.

  Next, as shown in FIG. 1B, a rectangular parallelepiped mold 3 (an example of a first molding member) in which a through hole 3a is formed in the central portion is disposed on a flat plate 1a. At this time, the protrusion 1b and the first intermediate molded body 10a are inserted through the through hole 3a.

  Next, as shown in FIG. 1C, a flat plate-shaped mold 4 is placed on the mold 3. The mold 4 is formed with injection holes 4a and 4b which are through holes. The injection holes 4a and 4b are formed so as to correspond to positions of a space s1 (see FIG. 3) described later. In the present embodiment, the number of injection holes is two, but the present invention is not limited to this.

  FIG. 3 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 3, the diameter d0 of the through hole 3a is longer than the outer diameter d2 of the winding 2. Therefore, a space s <b> 1 is formed between the outer peripheral surface f <b> 1 of the winding 2 and the wall surface F <b> 1 along the through hole 3 a of the mold 3. The space s1 communicates with the injection holes 4a and 4b.

  Next, resin is injected from the injection holes 4a and 4b to fill the space s1. Thereby, the 1st resin layer 5 (refer FIG. 4) along the outer peripheral surface f1 of the 1st intermediate molded object 10a is formed. The resin has heat dissipation and insulating properties. Further, the resin has a property of spreading between the windings 2 at the time of injection. Examples of such a resin include epoxy and silicon.

  Next, the first intermediate molded body 10a (hereinafter referred to as the second intermediate molded body 10b) on which the first resin layer 5 is formed is taken out from the molds 1, 3, and 4. An appearance of the second intermediate molded body 10b is shown in FIG. FIG. 4A is a perspective view of the second intermediate molded body 10b, and FIG. 4B is a top view of the second intermediate molded body 10b. As shown in FIGS. 4A and 4B, the second intermediate molded body 10b is a molded body in which the outer peripheral surface f1 of the first intermediate molded body 10a is covered with the first resin layer 5.

  The first molding process has been described above.

  Hereinafter, the second molding step will be described with reference to FIG. FIG. 5 is an explanatory diagram of the second molding step.

  First, as shown to Fig.5 (a), the 2nd intermediate molded object 10b is inserted in the recessed part 6a of the metal mold | die 6 (an example of a 2nd shaping | molding member). The recess 6 a is formed in the central part of the mold 6. The shape of the recess 6a is substantially the same as the outer shape of the second intermediate molded body 10b (see FIG. 6).

  Next, as shown in FIG. 5 (b), a plate-shaped mold 7 is placed on the mold 6. The mold 7 is formed with injection holes 7a and 7b which are through holes. The injection holes 7a and 7b are formed so as to correspond to positions of a space s2 (see FIG. 6) described later. In the present embodiment, the number of injection holes is two, but the present invention is not limited to this.

  The mold 7 is provided with a cylindrical protrusion 7c between the injection hole 7a and the injection hole 7b (see FIG. 6). The cross section of the protrusion 7c is, for example, a perfect circle.

  FIG. 6 is a cross-sectional view taken along the line BB in FIG. As shown in FIG. 6, the protruding portion 7c is inserted into the insertion hole 2a (reference numeral is not shown) of the second intermediate molded body 10b. The diameter d3 of the protrusion 7c is shorter than the diameter d1 of the insertion hole 2a. Therefore, a space (hereinafter referred to as a first space) is formed between the inner peripheral surface f2 of the second intermediate molded body 10b and the wall surface F2 of the protruding portion 7c.

  As shown in FIG. 6, a support 6b is formed in the recess 6a at a position h2 away from the bottom surface F3 of the recess 6a. The distance h2 can be said to be a distance between the bottom surface f4 (or the support portion 6b) and the bottom surface F3. The support portion 6b plays a role of supporting the first resin layer 5 when the winding 2 on which the first resin layer 5 is formed is inserted into the recess 6a. Thereby, a space (hereinafter referred to as a second space) is formed between the bottom surface f4 of the winding 2 and the bottom surface F3 of the recess 6a.

  As shown in FIG. 6, the mold 7 is formed with opening surfaces F4 of the injection holes 7a and 7b at positions away from the upper surface f3 by a distance h3. It can be said that the distance h3 is a distance between the upper surface f3 and the opening surface F4. The distance h3 is, for example, the same length as the distance h2. When the winding 2 on which the first resin layer 5 is formed is inserted into the recess 6a, a space (hereinafter referred to as a third space) is formed between the upper surface f3 of the winding 2 and the opening surface F4. Is formed.

  A space s2 in the figure is a space that is a combination of the first space, the second space, and the third space described above.

  Next, resin is injected from the injection holes 7a and 7b to fill the space s2. Thereby, the 2nd resin layer 8 (refer FIG. 7) along the internal peripheral surface f2, the upper surface f3, and the bottom face f4 of the 2nd intermediate molded object 10b is formed. This resin is, for example, the same resin used in the first molding step.

  A predetermined surface of the covering portion of the upper surface f3 and a predetermined surface of the covering portion of the bottom surface f4 of the second resin layer 8 are in contact with coil installation surfaces f5 (see FIG. 8) of core pieces 30a and 30b described later. Hereinafter, the surface in contact with the coil installation surface f5 in the second resin layer 8 is referred to as “contact surface”. The shape of the contact surface is preferably formed horizontally with respect to the coil installation surface f5. Thereby, the area which the 2nd resin layer 8 and the coil installation surface f5 contact can be enlarged, and more effective heat dissipation can be implement | achieved.

  Next, the second intermediate molded body 10b on which the second resin layer 8 is formed, that is, the coil 10 of the present embodiment is taken out of the molds 6 and 7. For example, by configuring the mold 6 to be separable, the coil 10 can be taken out from the molds 6 and 7 as shown in FIG.

  The appearance of the coil 10 thus taken out is shown in FIG. FIG. 7A is a perspective view of the coil 10, FIG. 7B is a side view of the coil 10, and FIG. 7C is a top view of the coil 10. As shown in FIGS. 7A to 7C, the coil 10 is a molded body in which the inner peripheral surface f2, the upper surface f3, and the bottom surface f4 of the second intermediate molded body 10b are covered with the second resin layer 8. is there.

  As shown in FIGS. 7A and 7C, the coil 10 is formed with an insertion hole 9 having a columnar shape (the same shape as the protruding portion 7c). The diameter of the insertion hole 9 is shorter than the diameter d0 (see FIG. 3) of the insertion hole 2a by the thickness of the second resin layer 8 covering the inner peripheral surface f2. A middle leg 12 (see FIG. 8), which will be described later, is inserted into the insertion hole 9.

  The surface 8a of the second resin layer 8 shown in FIGS. 7A to 7C is the contact surface described above, that is, of the covering portion of the upper surface f3 and the covering portion of the bottom surface f4 in the second resin layer 8. The surface is in contact with the coil installation surface f5 (see FIG. 8). As described above, the larger the area of the surface 8a, the more effectively the heat can be radiated. Therefore, the surface 8a is preferably formed horizontally with respect to the coil installation surface f5.

  The second molding process has been described above.

  As described above, according to the coil manufacturing method of the present embodiment, the first resin layer 5 and the second resin layer 8 are formed using a resin having an insulating property and a heat dissipation property, whereby a solenoid is formed. The coil which coat | covers the whole surface of the coil | winding 2 wound by shape can be manufactured. Thereby, since the area which can radiate heat can be enlarged, the coil excellent in heat dissipation can be provided, ensuring insulation.

  Further, according to the method for manufacturing a coil of the present embodiment, it is not necessary to provide a bobbin for winding the winding, even when a soft winding (for example, a litz wire) is used. Therefore, the cost of the bobbin can be reduced. In addition, since the winding and the resin are in direct contact without using a bobbin, a coil with excellent heat dissipation can be provided.

  Further, according to the manufacturing method of the present embodiment, the first resin layer 5 and the first resin layer 5 are formed using the molds 1, 3, 4, 6, and 7 in consideration of the outer shape of the winding 2 wound in a solenoid shape. Since the resin layer 8 of 2 is formed, waste of resin can be reduced compared with the case where the solenoid-like winding 2 is put in a box-shaped case in which the outer shape of the winding 2 is not considered and resin-sealed. it can.

  The coil 10 and the manufacturing method thereof according to the embodiment of the present invention have been described above.

  Hereinafter, a transformer including a coil manufactured by the above-described coil manufacturing method will be described with reference to FIGS. 8 to 10, the same components as those in FIGS. 1 to 7 are denoted by the same reference numerals, and the description thereof is omitted.

  First, the transformer 100 according to the present embodiment will be described with reference to FIGS. FIG. 8 is an exploded perspective view of the transformer 100. FIG. 9 is a perspective view showing the overall structure of the transformer 100.

  As shown in FIGS. 8 and 9, the transformer 100 includes a core 30 including core pieces 30 a and 30 b, a coil 10 as a primary side coil, and a coil 20 as a secondary side coil.

  The coil 20 is manufactured by the above-described method for manufacturing a coil according to the present embodiment, similarly to the coil 10, but the inner diameter (the diameter of the insertion hole) is different. That is, as shown in FIG. 8, the diameter of the insertion hole 13 of the coil 20 is equal to or greater than the outer diameter of the coil 10. Thereby, the coil 10 is inserted into the insertion hole 13 of the coil 20.

  Each of the core pieces 30a and 30b includes two outer legs 11 and a columnar middle leg 12 provided on the coil installation surface f5. The cross section of the middle leg 12 is, for example, a perfect circle, and its diameter is equal to or smaller than the diameter of the insertion hole 9 of the coil 10. The middle leg 12 is inserted through the insertion hole 9 of the coil 10 and the insertion hole 13 of the coil 20.

  8 and 9, the case where there is one secondary side coil is shown, but there may be two or more secondary side coils. For example, when another secondary coil having an insertion hole into which the coil 20 can be inserted is used, the coil 10 and the coil 20 are inserted into the insertion hole of the secondary coil.

  The transformer 100 has been described above.

  Next, the transformer 101 according to the present embodiment will be described with reference to FIG. FIG. 10 is a perspective view showing the overall structure of the transformer 101.

  As shown in FIG. 10, the transformer 101 includes a core 30 including core pieces 30a and 30b, and two coils 10 arranged so as to overlap in the vertical direction. One of the two coils 10 is used as a primary coil, and the other is used as a secondary coil.

  In addition, although FIG. 10 shows a case where there is one secondary coil, there may be two or more secondary coils.

  As described above, according to the transformers 100 and 101 of the present embodiment, since the coil manufactured by the manufacturing method of the present embodiment is used, a transformer having excellent heat dissipation while providing insulation is provided. it can.

  Further, according to the transformers 100 and 101 of the present embodiment, since the coil manufactured by the manufacturing method of the present embodiment is used, it is not necessary to provide a bobbin. Therefore, the cost of the bobbin can be reduced. In addition, when the bobbin is provided, a useless space may be generated between the primary side coil and the secondary side coil. In the present embodiment, the first resin layer 5 of the primary side coil is used. And the second resin layer 8 of the secondary side coil (in the case of the transformer 100), the second resin layer 8 of the primary side coil and the second resin layer 8 of the secondary side coil are brought into contact with each other Since it is possible (in the case of the transformer 101), useless space does not occur. Therefore, high integration is possible.

  In addition, according to the transformers 100 and 101 of the present embodiment, since the coil manufactured by the manufacturing method of the embodiment is used, a solenoid-like winding is used in a box-shaped case that does not consider the outer shape of the winding 2. Compared to the case of sealing with resin, waste of resin can be eliminated.

  Further, for example, in the case of configuring a transformer (for example, see the transformer 101 shown in FIG. 10) in which a plurality of coils 10 are stacked in the vertical direction, the vertical formation positions of the bottom surface F3 and the bottom surface f4 shown in FIG. By changing (in other words, changing the distance h2 and the distance h3), the second space (the space between the bottom surface f3 and the bottom surface F3), the third space (between the top surface f3 and the opening surface F4). It is possible to adjust the amount of resin filled in the space. That is, in the second resin layer 8, the thickness of the portion covering the upper surface f3 and the thickness of the portion covering the bottom surface f4 can be adjusted. Therefore, it can be adjusted to a desired leakage inductance (also referred to as leakage inductance).

  Further, for example, when configuring a transformer (for example, see the transformer 101 shown in FIG. 10) in which a plurality of coils 10 are stacked in the vertical direction, the thickness of the portion covering the upper surface f3 and the thickness of the portion covering the bottom surface f4 Can be reduced, the distance between the coils 10 can be reduced, and the transformer can be made compact in the vertical direction.

  Further, for example, using a plurality of coils 10 having different inner diameters (in other words, diameters of the insertion holes 9), the coil 10 having the shorter inner diameter is accommodated in the insertion hole 9 of the coil 10 having the longer inner diameter. 3 (for example, see the transformer 100 shown in FIGS. 8 and 9), the horizontal position (left-right direction) of the wall surface F1 shown in FIG. 3 is changed (in other words, the distance d0 and the distance). By changing the difference with d2, the amount of resin filled in the space s1 (that is, the thickness of the first resin layer 5) can be adjusted. Further, by changing the diameter d3 of the protrusion 7c shown in FIG. 6, the amount of resin filled in the first space (the space between the wall surface F2 and the inner peripheral surface f2) can be adjusted. That is, the thickness of the portion of the second resin layer 8 that covers the inner peripheral surface f2 can be adjusted. Therefore, it can be adjusted to a desired leakage inductance.

  Further, for example, using a plurality of coils 10 having different inner diameters (in other words, diameters of the insertion holes 9), the coil 10 having the shorter inner diameter is accommodated in the insertion hole 9 of the coil 10 having the longer inner diameter. When forming a transformer (for example, see the transformer 100 shown in FIGS. 8 and 9), the thickness of the first resin layer 5 and the thickness of the portion of the second resin layer 8 covering the inner peripheral surface f2 are reduced. Then, the distance between the coils 10 can be reduced, and the transformer can be made compact in the horizontal direction.

  The transformers 100 and 101 according to the embodiment of the present invention have been described above.

  Although the embodiments of the present invention have been described in detail so far, the present invention is not limited to the above-described embodiments, and various modifications are possible. Hereinafter, modified examples will be described.

(Modification 1)
In the embodiment, the case where the resins forming the first resin layer 5 and the second resin layer 8 are the same has been described as an example. However, the resin forming the first resin layer 5 and the second resin are the same. The resin forming the resin layer 8 may be different. However, any resin has insulating properties and heat dissipation properties, and has properties of spreading between the windings 2 at the time of injection.

(Modification 2)
In the embodiment, the case where the shape of the cross section of the middle leg 12 and the insertion holes 9 and 13 is a perfect circle has been described as an example, but the shape may be an ellipse or an ellipse.

(Modification 3)
In the transformers 100 and 101 described in the embodiment, for example, a heat conductive member such as an aluminum plate may be provided in contact with the first resin layer 5. Thereby, the heat dissipation effect can be further enhanced.

(Modification 4)
In the embodiment, the case where the winding 2 is solenoid-wound has been described as an example. However, the present invention is not limited to this, and for example, spiral winding may be used.

(Modification 5)
In the embodiment, the case where the coil installation surface f5 of the core pieces 30a and 30b is larger than the diameter of the coil 10 or the coil 20 is exemplified. Also good. In this case, it is preferable to increase the thickness of the resin in the vertical direction where the core pieces 30a and 30b are not in contact with the coil installation surface f5. For example, when it is arranged on the heat sink so that the bottom surface of the core piece 30b is in contact, the thickness of the resin in the downward direction at a portion not in contact with the coil installation surface f5 of the core piece 30b is increased, and the bottom surface of the second resin layer 8 is increased. It is preferable that 8a contacts the heat sink. Thereby, the heat dissipation effect can be further enhanced.

  The present invention is useful for coils, transformers, and methods for manufacturing coils.

1, 3, 4, 6, 7 Mold 1a Flat plate 1b, 7c Projection part 2 Winding 2a, 9, 13 Insertion hole 3a Through hole 4a, 4b, 7a, 7b Resin injection hole 5 First resin layer 6a Concave part 6b Support portion 8 Second resin layer resin 10, 20 Coil 10a First intermediate molded body 10b Second intermediate molded body 11 Outer foot 12 Middle foot 30 Core 30a, 30b Core piece 100, 101 Transformer

Claims (12)

A coil having a wound winding and having a hollow portion formed,
Formed of a resin having heat dissipation and insulating properties, and provided with a resin layer covering the entire surface of the wound winding,
coil. The resin layer is
A first resin layer covering the outer peripheral surface of the wound winding;
A second resin layer covering a surface other than the outer peripheral surface,
The coil according to claim 1. Surfaces other than the outer peripheral surface are the inner peripheral surface, the upper surface, and the bottom surface of the wound winding,
The coil according to claim 2. The shape of the surface in contact with the coil installation surface of the core of the second resin layer is horizontal to the coil installation surface.
The coil according to claim 2 or 3. The winding is wound in a solenoid shape,
The coil according to any one of claims 1 to 4. A plurality of coils according to any one of claims 1 to 5;
A core formed with a middle leg that is inserted through each insertion hole of the plurality of coils, and
The plurality of coils are:
Including one primary coil and at least one secondary coil;
Trance. The primary coil is disposed in an insertion hole of the secondary coil.
The transformer according to claim 6. The primary coil and the secondary coil are arranged so as to overlap in the vertical direction,
The transformer according to claim 6. Winding the winding, creating a first intermediate molded body with a hollow portion,
The first intermediate molded body is accommodated in a through hole having a diameter larger than the outer diameter of the first intermediate molded body formed in the first molded member, and the outer peripheral surface of the first intermediate molded body and the through hole are accommodated. Injecting a resin having heat dissipation and insulation into the space between the walls along the wall, creating a second intermediate molded body having a first resin layer covering the outer peripheral surface of the first intermediate molded body,
The second intermediate molded body is accommodated in a recess having substantially the same shape as the outer shape of the second intermediate molded body formed on the second molded member, and between the surfaces other than the outer peripheral surface of the second intermediate molded body. Injecting the resin into the space to create a coil having a second resin layer covering a surface other than the outer peripheral surface of the molded body,
Coil manufacturing method. Surfaces other than the outer peripheral surface are the inner peripheral surface, the upper surface, and the bottom surface of the wound winding,
The method for manufacturing a coil according to claim 9. The surface of the second resin layer that contacts the core installation surface of the core is formed horizontally with respect to the coil installation surface of the core.
The method for manufacturing a coil according to claim 9 or 10. Winding the winding in a solenoid shape;
The method for manufacturing a coil according to any one of claims 9 to 11.

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