JP2020021858A - Reactor - Google Patents

Abstract

To provide a reactor that can efficiently release the heat of a coil to a core.SOLUTION: A flange portion 34 has a through hole 38, and a core 50 has a protrusion 64 protruding toward a bobbin 30 at a position facing the through hole 38, and the protrusion 64 is located on the root side and has a first protrusion 64r having a diameter larger than the through hole 38 and a second protrusion 64t located on the distal end side and having a diameter smaller than that of the through hole 38, and the axial length wt of the through hole 38 is longer than the axial length h2 of the second protrusion 64t, a gap (first gap 66) is formed between the coil 20 and the second protrusion 64t in a state in which the second protrusion 64t is inserted into the through hole 38, and the gap (first gap 66) is filled with a potting material 70.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reactor including a coil, a bobbin around which the coil is wound, a core that houses the coil and the bobbin, and a potting material that is filled inside the core.

  A vehicle driven by an electric motor has a power control unit (PCU) for controlling electric power of a battery, and the PCU has a DC-DC converter. The DC-DC converter may be provided with a reactor.

  Patent Literature 1 discloses a reactor in which a coil (coil winding) wound around a bobbin (support) is housed inside a core (ferrite base), and further filled with a potting material (resin). In this reactor, a recess is provided on the bottom (base) of the core, and a protrusion is provided on the flange (lower flange) of the bobbin. Good positional relationship is maintained.

JP 2008-91197 A

  The bobbin is often formed of a material having a low thermal conductivity, for example, polyphenylene sulfide (PPS) resin, and has relatively low heat radiation efficiency. Furthermore, when the projection is provided on the bobbin as in the reactor of Patent Document 1, the thickness of the portion where the projection is disposed becomes thick, so that the heat of the coil is hardly released.

  It is possible to improve the thermal conductivity by mixing a metal filler with the PPS resin. However, in such a case, the fluidity of the PPS resin is deteriorated, so that it is difficult to form the bobbin. For this reason, a technique of improving the thermal conductivity by mixing a metal filler with the PPS resin cannot be adopted.

  The present invention has been made in view of such problems, and has as its object to provide a reactor that can efficiently release heat of a coil to a core.

A first aspect of the present invention provides:
Coils and
A bobbin around which the coil is wound;
A core accommodating the coil and the bobbin therein;
And a potting material to be filled into the core,
The bobbin has a trunk on which the coil is wound, and a flange extending radially from an end of the trunk about an axis,
The collar has a through hole,
The core has a protrusion protruding toward the bobbin at a position facing the through hole,
The projection has a first projection located on the root side and having a diameter larger than the through hole, and a second projection located on the tip side and having a diameter smaller than the through hole,
In a state where the length of the through hole in the axial direction is longer than the length of the second protrusion in the axial direction, and the second protrusion is inserted into the through hole, the coil and the second protrusion are formed. And a gap is formed, and the gap is filled with the potting material.

A second aspect of the present invention provides:
Coils and
A bobbin around which the coil is wound;
A core accommodating the coil and the bobbin therein;
And a potting material to be filled into the core,
The bobbin has a trunk on which the coil is wound, and a flange extending radially from an end of the trunk about an axis,
The collar has a through hole,
The core has a protrusion protruding toward the bobbin at a position facing the through hole,
The through-hole has a first through-hole located on the projection side and having a diameter larger than the projection, and a second through-hole located on the coil side and having a diameter smaller than the projection. And
The length of the protrusion in the axial direction is longer than the length of the first through hole in the axial direction, and the coil and the protrusion are connected to each other in a state where the protrusion is inserted into the first through hole. A space is formed in the second through hole between the holes, and the space is filled with the potting material.

  According to the present invention, the contact area between the coil and the potting material can be increased, and the heat of the coil can be efficiently released to the core.

FIG. 1 is a perspective view of the reactor according to the first embodiment. FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 is a plan view of the flange portion. FIG. 4 is an enlarged cross-sectional view of a protrusion and a through hole according to the second embodiment.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a reactor according to the present invention will be described in detail with reference to the accompanying drawings, showing preferred embodiments.

[1. First Embodiment]
[1.1. Configuration of reactor 10]
As shown in FIGS. 1 and 2, the reactor 10 according to the present embodiment includes a coil 20, a bobbin 30 around which the coil 20 is wound, a core 50 accommodating the coil 20 and the bobbin 30 therein, and a core 50. And a potting material 70 filled therein. The central axes of the coil 20, the bobbin 30, and the core 50 coincide with each other, and this becomes the reactor 10 and the central axis (hereinafter, referred to as the axis A).

  The coil 20 is formed into a cylindrical shape around the axis A by winding the electric wire around the bobbin 30 (the body portion 32) in the circumferential direction. The electric wire may be any of a round wire, a square wire, and a flat wire. From the coil 20, a coil terminal 22a formed at one end of the electric wire and a coil terminal 22b formed at the other end of the electric wire are drawn out. The coil terminal 22a is drawn out of the core 50 from a drawing hole 60a described later. The coil terminal 22b is drawn out of the core 50 from a drawing hole 60b described later.

  The bobbin 30 is formed of, for example, PPS resin. The thermal conductivity of the PPS resin is about 0.3 W / m · K. The bobbin 30 has a body 32 and two flanges 34. The body 32 has a cylindrical shape around the axis A, and the coil 20 is wound around the outer peripheral surface. A flange portion 34 is formed on one and the other of the body portion 32 in the axial direction. The flange 34 extends in a radial direction about the axis A. As shown in FIG. 3, the flange portion 34 of the present embodiment has a plurality of band members 36 extending in different directions, and in the present embodiment, four band members 36. Each band member 36 is, for example, rectangular. The plurality of belt-shaped members 36 are arranged at equal intervals along the circumferential direction with respect to the trunk 32, and at 90 ° intervals in the present embodiment. Each band-shaped member 36 has a through hole 38 penetrating in the axial direction. The through hole 38 will be described in [1.2] below.

  The core 50 is formed of a magnetic material, for example, ferrite. As shown in FIG. 2, the core 50 has a first core 50a located on one side in the axial direction and a second core 50b located on the other side in the axial direction. Since the first core 50a and the second core 50b of the present embodiment have the same shape, the first core 50a will be mainly described here. The first core 50a has a bottom 52, a side 54, a center 56, and an opening 58. The bottom part 52 is located at one end of the first core 50a in the axial direction. The bottom part 52 has an inner bottom surface 62 facing the inside of the first core 50a. The same number of protrusions 64 as the through holes 38 of the bobbin 30 are formed on the inner bottom surface 62. The protrusion 64 will be described in [1.2] below. The side portion 54 has a cylindrical shape extending along the axial direction from the periphery of the bottom portion 52, and surrounds the coil 20. The center portion 56 has a cylindrical shape extending along the axial direction from the center of the bottom portion 52, and is inserted through the body portion 32 of the bobbin 30. The opening 58 is a circular opening located at the other end of the first core 50a in the axial direction. The first core 50a and the second core 50b have their bottoms 52 facing outward in the axial direction, and their ends on the opening 58 side are in contact with each other.

  As shown in FIG. 1, the side portion 54 of the first core 50a has a part of the lead holes 60a and 60b penetrating from the inner peripheral side to the outer peripheral side and opening to the second core 50b side. Similarly, the side portion 54 of the second core 50b has a part of the lead holes 60a and 60b penetrating from the inner peripheral side to the outer peripheral side and opening to the first core 50a side. In a state where the first core 50a and the second core 50b are combined, a part of the drawing hole 60a of the first core 50a and a part of the drawing hole 60a of the second core 50b are combined to form one drawing hole. 60a is formed. Similarly, in a state where the first core 50a and the second core 50b are combined, a part of the extraction hole 60b of the first core 50a and a part of the extraction hole 60b of the second core 50b are combined, and 1 One extraction hole 60b is formed. The lead holes 60a and 60b guide the coil terminals 22a and 22b from the inside of the core 50 to the outside. The extraction hole 60a is located closer to the bottom 52 of the first core 50a than the extraction hole 60b, and the extraction hole 60b is located closer to the bottom 52 of the second core 50b than the extraction hole 60a. Further, the extraction hole 60a and the extraction hole 60b are formed at different positions in the circumferential direction of the core 50 within a range of less than 180 ° around the axis A. Note that the lead hole 60a may be provided only in the first core 50a, and the lead hole 60b may be provided only in the second core 50b.

  The potting material 70 is a member having a higher thermal conductivity than the material of the bobbin 30. For example, it is a highly thermally conductive epoxy resin in which a metal filler such as alumina is mixed into an epoxy resin. By mixing a metal filler in the epoxy resin, the thermal conductivity of the epoxy resin can be increased to about 2.0 W / m · K. The potting material 70 fills the space inside the core 50, that is, the gap where the coil 20 and the bobbin 30 do not exist. For example, between the outer peripheral surface of the coil 20 and the inner peripheral surface of the side portion 54, between the inner peripheral surface of the body portion 32 and the outer peripheral surface of the central portion 56, a first gap 66 described in [1.2] below. And the second gap 68 and the like.

[1.2. Through hole 38 and projection 64]
The through hole 38 of the flange 34 will be described with reference to FIGS. Each through hole 38 is formed at the same distance from the axis A. Assuming that the thickness of the belt-shaped member 36 in the axial direction is wt, the length of the through hole 38 in the axial direction is wt. The through holes 38 have the same diameter (φt) from one side to the other side. The planar shape (shape viewed from the axial direction) of the through hole 38 is circular.

  The protrusion 64 of the bottom 52 will be described with reference to a partially enlarged view of FIG. The protrusion 64 is formed on the inner bottom surface 62 at a position facing the through hole 38 of the belt-shaped member 36. The protrusion 64 has a first protrusion 64r and a second protrusion 64t on the same axis. The first protrusion 64r is located on the root side of the protrusion 64 (the inner bottom surface 62 side). The diameter φ1 of the first protrusion 64r is larger than the diameter φt of the through hole 38. On the other hand, the second protrusion 64t is located on the tip side (the coil 20 side) of the protrusion 64. The diameter φ2 of the second protrusion 64t is smaller than the diameter φt of the through hole 38. As described above, the protrusion 64 has a stepped structure in which the second protrusion 64t can be inserted into the through hole 38 and the first protrusion 64r cannot be inserted into the through hole 38. The length (height) h2 of the second protrusion 64t in the axial direction is shorter than the length wt of the through hole 38 in the axial direction. With such a structure, when the second protrusion 64t is inserted into the through hole 38, the end surface of the first protrusion 64r abuts on the belt-shaped member 36, and the first gap 66 is provided between the coil 20 and the second protrusion 64t. Is formed. Further, since the first protrusion 64r functions as a spacer, a second gap 68 is formed between the flange 34 (the band-shaped member 36) and the bottom 52. As described above, the first gap 66 and the second gap 68 are filled with the potting material 70.

[1.3. Manufacturing method of reactor 10]
An electric wire is wound around the body 32 of the bobbin 30 to form the coil 20. At this time, the coil terminals 22a and 22b are pulled out in a predetermined direction. Next, the bobbin 30 is placed inside the first core 50a. At this time, the bobbin 30 is positioned by extracting the coil terminal 22a from the extraction hole 60a of the first core 50a and inserting the second protrusion 64t into the through hole 38 of the belt-shaped member 36. Next, the second core 50b is put on the first core 50a containing the bobbin 30. The first core 50a and the second core 50b are aligned using the lead holes 60a, 60b of the first core 50a and the lead holes 60a, 60b of the second core 50b. At this time, the coil terminal 22b is pulled out from the lead-out hole 60b of the second core 50b, and the second protrusion 64t is inserted into the through-hole 38 of the belt-shaped member 36.

  Next, the first core 50a and the second core 50b are fixed with a jig or the like, and the liquid potting material 70 is injected into the core 50 from one or both of the one or both of the drawing holes 60a and 60b. The potting material 70 penetrates into the gap inside the core 50 including the first gap 66 and the second gap 68. Note that the potting material 70 that enters the first gap 66 passes through a small gap between the protrusion 64 and the band-shaped member 36 and a small gap between the coil 20 and the band-shaped member 36. Next, heat is applied to the core 50. Then, the potting material 70 is cured, and the first core 50a and the second core 50b are bonded by the potting material 70. Thus, the reactor 10 in which the coil 20, the bobbin 30, the core 50, and the potting material 70 are integrated is obtained.

[1.4. Modification]
In the first embodiment, the planar shape of the through hole 38 is circular, but the planar shape of the through hole 38 can be arbitrarily set. The size of the through hole 38 (φt in the case of a circle) can also be set arbitrarily. Further, the shape and size of each through hole 38 may be different. The number of the belt-like members 36 can also be set arbitrarily. However, it is needless to say that the second protrusion 64t must be insertable into the through hole 38 and the first protrusion 64r is not insertable into the through hole 38.

  In the first embodiment, the flange 34 has a rectangular band shape (band-like member 36). Instead, the flange portion 34 may have a disk shape. Further, other shapes may be used. However, the use of the band-shaped member 36 can increase the contact area between the coil 20 and the potting material 70 as compared with the use of the disc-shaped flange 34, thereby releasing more heat of the coil 20. Can be.

  In the first embodiment, each of the first core 50a and the second core 50b has a protrusion 64, and one and the other flanges 34 of the bobbin 30 each have a through hole 38. Instead, only the first core 50a may have the protrusion 64, and only one flange 34 of the bobbin 30 may have the through hole 38.

  In the first embodiment, the first core 50a and the second core 50b have the same shape. However, if the core 50 has a cylindrical shape, the first core 50a and the second core 50b do not have to have the same shape. For example, the second core 50b may be a flat plate that closes the first core 50a. Further, instead of the core 50 being composed of two core members (the first core 50a and the second core 50b), the core 50 may be composed of three or more core members.

[2. Second Embodiment]
In the first embodiment, the through hole 38 has the same diameter (φt) from one side to the other side, and the projection 64 has a stepped structure. Conversely, as shown in FIG. 4, the protrusion 64 may have the same diameter (φp) from one side to the other, and the through hole 38 may have a stepped structure.

  The configuration of the second embodiment is substantially the same as the configuration of the first embodiment. Hereinafter, a configuration of the second embodiment that is different from the configuration of the first embodiment will be described.

  The through hole 38 has a first through hole 38a and a second through hole 38b on the same axis. The first through hole 38a is located on the protruding portion 64 side. The diameter φa of the first through hole 38a is larger than the diameter φp of the projection 64. The second through hole 38b is located on the coil 20 side. The diameter φb of the second through hole 38b is smaller than the diameter φp of the projection 64. As described above, the through hole 38 has a stepped structure in which the protrusion 64 can be inserted into the first through hole 38a and the protrusion 64 cannot be inserted into the second through hole 38b. The axial length wa of the first through hole 38a is shorter than the axial length (height) hp of the protrusion 64. With such a structure, when the projection 64 is inserted into the first through hole 38a, the end surface of the projection 64 abuts on the belt-shaped member 36, and the first gap 66 is formed between the coil 20 and the projection 64. . Furthermore, since the protrusion 64 functions as a spacer, a second gap 68 is formed between the flange 34 (the band-shaped member 36) and the bottom 52. The first gap 66 and the second gap 68 are filled with a potting material 70.

[3. Invention obtained from the embodiment]
The invention that can be grasped from the above embodiment and modifications will be described below.

A first aspect of the present invention provides:
A coil 20;
A bobbin 30 around which the coil 20 is wound;
A core 50 that houses the coil 20 and the bobbin 30 therein;
A potting material 70 filled in the core 50, the reactor 10 comprising:
The bobbin 30 has a body 32 around which the coil 20 is wound, and a flange 34 extending radially from the end of the body 32 around the axis A,
The flange portion 34 has a through hole 38,
The core 50 has a projection 64 protruding toward the bobbin 30 at a position facing the through hole 38,
The protrusion 64 has a first protrusion 64r located on the root side and having a diameter larger than the through hole 38, and a second protrusion 64t located on the tip side and having a diameter smaller than the through hole 38. ,
When the axial length wt of the through hole 38 in the axial direction is longer than the axial length h2 of the second projection 64t, and the second projection 64t is inserted into the through hole 38, the coil 20 and the second projection are formed. A gap (first gap 66) is formed between the gap and the first gap 66t, and the potting material 70 is filled in the gap (first gap 66).

  Comparing the bobbin 30 and the potting material 70, the thermal conductivity of the potting material 70 (2.0 W / m · K for epoxy resin) is better than that of the bobbin 30 (0.3 W / m for PPS resin). -It is larger than K). According to the above configuration, the potting material 70 fills the first gap 66 between the coil 20 and the second protrusion 64t in a state where the second protrusion 64t is inserted into the through hole 38 and the bobbin 30 is positioned. Therefore, the contact area between the coil 20 and the potting material 70 can be increased, and the heat of the coil 20 can be efficiently released to the core 50. In addition, since the through hole 38 is provided in the flange portion 34 of the bobbin 30, the bobbin 30 at the portion of the through hole 38 becomes thin (zero in thickness). From this viewpoint, the heat radiation efficiency is improved.

In the present invention,
The flange 34 may include a plurality of band-shaped members 36 extending in different directions.

  According to the above configuration, the contact area between the bobbin 30 and the coil 20 is smaller than that of the disc-shaped flange 34, and the contact area between the potting material 70 and the coil 20 is increased, so that the heat radiation efficiency is further improved. Further, since the band-shaped member 36 uses less material than the disc-shaped flange 34, the weight of the bobbin 30 can be reduced.

A second aspect of the present invention provides:
A coil 20;
A bobbin 30 around which the coil 20 is wound;
A core 50 that houses the coil 20 and the bobbin 30 therein;
A potting material 70 filled in the core 50, the reactor 10 comprising:
The bobbin 30 has a body 32 around which the coil 20 is wound, and a flange 34 extending radially from the end of the body 32 around the axis A,
The flange portion 34 has a through hole 38,
The core 50 has a projection 64 protruding toward the bobbin 30 at a position facing the through hole 38,
The through-hole 38 has a first through-hole 38a located on the protrusion 64 side and having a larger diameter than the protrusion 64, a second through-hole 38b located on the coil 20 side and has a smaller diameter than the protrusion 64, Has,
When the length hp of the protrusion 64 in the axial direction is longer than the length wa of the first through hole 38a in the axial direction, and the protrusion 64 is inserted into the first through hole 38a, the coil 20 and the protrusion 64 A gap (first gap 66) is formed in the second through hole 38b between the gaps, and the gap (first gap 66) is filled with the potting material 70.

  According to the above configuration, the potting material 70 is filled in the first gap 66 between the coil 20 and the projection 64 in a state where the projection 64 is inserted into the through hole 38 and the bobbin 30 is positioned. The contact area between the coil 20 and the potting material 70 can be increased, and the heat of the coil 20 can be efficiently released to the core 50. In addition, since the through hole 38 is provided in the flange portion 34 of the bobbin 30, the bobbin 30 at the portion of the through hole 38 becomes thin (zero in thickness). From this viewpoint, the heat radiation efficiency is improved.

  In addition, the reactor according to the present invention is not limited to the above-described embodiment, but may adopt various configurations without departing from the gist of the present invention.

Reference Signs List 10 reactor 20 coil 30 bobbin 32 trunk 34 flange 38a through hole 38a first through hole 38b second through hole 50 core 64 projecting part 64r first projecting part 64t second Projection 66: First void (void) 70: Potting material

Claims (3)

Coils and
A bobbin around which the coil is wound;
A core accommodating the coil and the bobbin therein;
And a potting material to be filled into the core,
The bobbin has a trunk on which the coil is wound, and a flange extending radially from an end of the trunk about an axis,
The collar has a through hole,
The core has a protrusion protruding toward the bobbin at a position facing the through hole,
The projection has a first projection located on the root side and having a diameter larger than the through hole, and a second projection located on the tip side and having a diameter smaller than the through hole,
In a state where the length of the through hole in the axial direction is longer than the length of the second protrusion in the axial direction, the coil and the second protrusion are inserted in a state where the second protrusion is inserted into the through hole. And a gap is formed between the reactor and the potting material. The reactor according to claim 1,
The reactor, wherein the flange has a plurality of band-shaped members extending in different directions. Coils and
A bobbin around which the coil is wound;
A core accommodating the coil and the bobbin therein;
And a potting material to be filled into the core,
The bobbin has a trunk on which the coil is wound, and a flange extending radially from an end of the trunk about an axis,
The collar has a through hole,
The core has a protrusion protruding toward the bobbin at a position facing the through hole,
The through hole has a first through hole located on the projection side and having a diameter larger than the projection, and a second through hole located on the coil side and having a diameter smaller than the projection. And
The length of the protrusion in the axial direction is longer than the length of the first through hole in the axial direction, and in a state where the protrusion is inserted into the first through hole, the coil and the protrusion are connected to each other. A reactor, wherein a void is formed in a second through hole between the two, and the void is filled with the potting material.

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