JP6015419B2 - Reactor and its manufacturing method - Google Patents

Description

  The present invention relates to a reactor and a manufacturing method thereof.

  The reactor includes a reactor body including a reactor core (hereinafter sometimes simply referred to as “core”) made of a laminated body of magnetic steel sheets or a dust core, and a coil wound around the reactor core, A housing for housing or a housing such as a case.

In order to avoid the entire reactor from becoming high temperature due to heat generated from the coil and / or core during operation, the following heat dissipation structure is adopted.
Generally, a heat radiating plate (hereinafter referred to as “heat sink”) is provided below the bottom of the housing, or the bottom of the housing itself is used as a heat sink. Furthermore, a cooler for circulating cooling water or air is provided below the heat sink.
In accordance with the above structure, a heat radiating material is also used between the housing and the reactor main body.
FIG. 4 of Patent Document 1 describes a structure in which a resin is filled between a casing and a reactor main body and heat is radiated through the resin. However, large equipment is required for filling and curing the resin, and the processing cost is high.
FIG. 1 of Patent Document 1 discloses a structure in which a heat dissipation sheet is interposed between the bottom of the housing and the reactor main body. With this structure, a heat dissipation structure can be obtained at a low cost with a simple process.

JP 2012-124401 A

  However, since the heat dissipation sheet has flexibility, it is easy to bend, and an air layer may remain between the bottom of the housing and the heat dissipation sheet. If there is a layer of air, heat conduction is hindered and heat dissipation performance is degraded.

  This invention is made | formed in view of the said situation, and it aims at providing the reactor which can improve heat dissipation at low cost, and its manufacturing method.

The reactor of the present invention is
A reactor body including a reactor core and a coil wound around the reactor core;
A housing for housing the reactor body;
A reactor comprising a heat dissipation sheet interposed between the casing and the coil of the reactor body and compressed in the thickness direction by the coil;
The heat radiating sheet has at least one vent hole that is formed through the heat radiating sheet in the thickness direction and is closed by compression by the coil.

The method for producing the reactor of the present invention is as follows.
A reactor body including a reactor core and a coil wound around the reactor core;
A housing for housing the reactor body;
A reactor manufacturing method comprising a heat dissipation sheet interposed between the casing and the coil of the reactor body,
Placing a heat radiating sheet having at least one vent hole formed through the casing in the thickness direction; and
A step of attaching the reactor main body in the casing so that the heat radiating sheet is compressed in the thickness direction by the coil and the air hole is closed by the compression.

  ADVANTAGE OF THE INVENTION According to this invention, the reactor which can improve heat dissipation at low cost, and its manufacturing method can be provided.

It is a manufacturing-process figure of the reactor of one Embodiment which concerns on this invention. It is a manufacturing-process figure of the reactor of one Embodiment which concerns on this invention. It is a manufacturing-process figure of the reactor of one Embodiment which concerns on this invention. It is a manufacturing-process figure of the reactor of one Embodiment which concerns on this invention. It is a perspective view of a thermal radiation sheet. It is sectional drawing which shows the design change of a thermal radiation sheet.

With reference to drawings, the reactor of one Embodiment which concerns on this invention, and its manufacturing method are demonstrated.
1A to 1D are manufacturing process diagrams. In these drawings, the core and coil of the reactor main body are shown in a side view, and the others are shown in a sectional view.
FIG. 2 is a perspective view of the heat dissipation sheet.
FIG. 3 is a cross-sectional view showing a design change of the heat dissipation sheet.
Both figures are schematic diagrams.

First, as shown in FIG. 1A, a housing 20 such as a housing or a case is prepared.
The housing 20 includes a bottom portion 21 and a side portion 22, and an upper portion is open.

Next, as shown in FIG. 1B, the heat dissipation sheet 30 is placed on the inner surface (hereinafter referred to as “inner bottom surface”) 21 </ b> S of the bottom 21 of the housing 20. At this time, the heat radiating sheet 30 may be attached to the inner bottom surface 21S of the housing 20 using an adhesive or the like.
The heat dissipation sheet 30 is an insulating sheet having thermal conductivity and flexibility (flexibility).
As a material of the heat dissipation sheet 30, a resin having excellent heat resistance, good thermal conductivity, and elasticity is preferable, and a silicone resin and a urethane resin are preferable.

In this embodiment, as shown in FIG. 1B and FIG. 2, a heat radiating sheet 30 having at least one vent hole 31 penetrating in the thickness direction is used.
The heat dissipation sheet 30 of this embodiment has a single layer structure.
As the heat radiating sheet 30, a commercially available heat radiating sheet that has been processed to open the air holes 31 using a drill or the like can be used.
When a commercially available heat radiation sheet is punched out so as to fit the reactor housing size, the air holes 31 can be formed by punching at the same time. In this case, the processing steps of the heat dissipation sheet 30 do not increase, which is preferable.
In the illustrated example, a plurality of ventilation holes 31 are formed in an array in a matrix in plan view in the heat dissipation sheet 30. The number and arrangement of the air holes 31 in the heat dissipation sheet 30 can be appropriately designed.

Next, as shown in FIG. 1C and FIG. 1D, a reactor including a reactor core 11 made of a laminated body of magnetic steel sheets or a dust core and a coil 12 wound around the reactor core 11 in a casing 20. The main body 10 is attached.
In this step, the heat dissipation sheet 30 is compressed in the thickness direction by the coil 12.
As shown in the enlarged view in FIG. 1D, the coil 12 has a plurality of convex portions 12 </ b> A projecting downward at the lower end portion thereof. Due to the concavo-convex shape of the plurality of convex portions 12A, compressive stress is applied not only to the thickness direction but also to the surface direction with respect to the vent hole 31 of the heat dissipation sheet 30. By this action, the vent hole 31 is closed.
In the enlarged view in FIG. 1D, hatching of the heat radiating sheet 30 is omitted for easy visual recognition. In the enlarged view in FIG. 1D, the compressive stress in the surface direction with respect to the vent hole 31 is schematically indicated by an arrow.

The reactor 1 is manufactured as described above.
When trying to attach the heat dissipation sheet 30 or the reactor main body 10 in the housing 20, the vent hole 31 of the heat dissipation sheet 30 is open, so that the air enters between the bottom 21 of the housing 20 and the heat dissipation sheet 30. Excess air is discharged upward through the vent hole 31. Therefore, an air layer remains between the housing 20 and the reactor main body 10 after the reactor main body 10 is attached, and a reduction in heat dissipation performance is suppressed.

  After completing the installation of the reactor main body 10 in the housing 20, the air holes 31 of the heat dissipation sheet 30 are closed by compressive stress. Therefore, it is suppressed that the heat dissipation performance falls by the air in the vent hole 31.

Reactor 1 is
A reactor body 10 including a reactor core 11 and a coil 12 wound around the reactor core 11;
A housing 20 for housing the reactor body 10;
A heat dissipating sheet 30 interposed between the casing 20 and the coil 12 of the reactor body 10 and compressed in the thickness direction by the coil 12 is provided.
In the reactor 1, the heat radiating sheet 30 has at least one vent hole 31 formed so as to penetrate the heat radiating sheet 30 in the thickness direction and closed by compression by the coil 12.

Before the installation of the reactor main body 10 is completed, an effect of releasing excess air through the vent hole 31 is effectively obtained, and after the installation of the reactor main body 10 is completed, the vent hole 31 is satisfactorily closed. The non-compressed hole diameter d (μm) of the thirty vent holes 31 preferably satisfies the following formula (X).
0.1 (μm) ≦ d (μm) ≦ (t × A) / 100 (μm) (X)
(In the formula, t represents the thickness (μm) of the heat dissipation sheet before compression, and A represents the compression ratio (%) of the heat dissipation sheet by the coil.)

  In this specification, the compression rate (%) of the heat dissipation sheet by the coil is defined as the minimum thickness after compression / thickness before compression × 100 (%).

If the hole diameter d in the uncompressed state of the vent hole 31 is less than 0.1 μm, the effect that excess air between the bottom portion 21 of the housing 20 and the heat dissipation sheet 30 is released upward through the vent hole 31 is effective. There is a risk that it cannot be obtained.
If the uncompressed hole diameter d of the vent hole 31 of the heat radiating sheet 30 exceeds (t × A) / 100 μm, the vent hole 31 may not be sufficiently closed after the reactor body 10 is completely installed in the housing 20. There is.

The thickness t before compression of the heat dissipation sheet 30 is not particularly limited, and is preferably 0.5 to 3 mm, for example.
The compression rate A of the heat radiation sheet 30 is not particularly limited, and is preferably 20 to 80%, for example.

Before attaching the heat radiation sheet 30, it is preferable that the inner bottom surface 21 </ b> S (the surface on which the heat radiation sheet 30 is placed) of the housing 20 is roughened in advance.
In this case, a minute gap is formed between the inner bottom surface 21S of the housing 20 and the heat radiating sheet 30 due to minute irregularities formed on the inner bottom surface 21S by the roughening process.
When the heat radiating sheet 30 or the reactor main body 10 is to be installed in the housing 20, excess air that has entered between the bottom 21 of the housing 20 and the heat radiating sheet 30 is laterally passed through the minute gap. It becomes easy to be released from. The minute gap is closed after the heat dissipation sheet 30 is compressed by the coil 12.
Examples of the roughening treatment include shot blasting and chemical etching.

Since the effect of releasing excess air through the minute gap is effectively obtained before the installation of the reactor body 10 is completed, and the minute gap is satisfactorily closed after the installation of the reactor body 10 is completed. The arithmetic average roughness Ra of the 20 inner bottom surfaces 21S preferably satisfies the following formula (Y).
5 (μm) ≦ Ra (μm) ≦ t / 2 (μm) (Y)
(In the formula, t is the thickness (μm) of the heat dissipation sheet before compression.)

If the arithmetic average roughness Ra of the inner bottom surface 21S is less than 5 μm, the effect of releasing excess air from the side may not be obtained effectively.
When the arithmetic average roughness Ra of the inner bottom surface 21S exceeds t / 2 μm, a minute gap remains between the bottom portion 21 of the housing 20 and the heat radiating sheet 30 after compression, and the heat radiation performance may be deteriorated.

  In die-casting or the like, the surface roughness of the inner bottom surface 21S of the housing 20 is originally large and the above formula (Y) may be satisfied. In this case, it can be used as it is without roughening.

  In the present embodiment, unlike the structure in which resin is filled between the housing and the reactor main body and heat is radiated through the resin, the heat radiation sheet 30 is inserted between the housing 20 and the reactor main body 10. A structure for radiating heat through the heat radiating sheet 30 is employed. Therefore, a resin filling and curing facility is unnecessary, and the reactor 1 can be manufactured at low cost.

  In the present embodiment, since the heat radiating sheet 30 having the air holes 31 is used, it is possible to suppress an air layer from remaining between the housing 20 and the heat radiating sheet 30. The vent hole 31 is closed after being compressed by the coil 12. Therefore, in the present embodiment, a decrease in heat dissipation performance due to excess air is suppressed.

  As shown in the example of the design change shown in FIG. 3, it has a multilayer structure of a high hardness layer 42 having a relatively high hardness and a low hardness layer 43 having a relatively low hardness, and is formed so as to penetrate in the thickness direction of the sheet. The heat radiating sheet 40 having at least one vent hole 41 may be used.

It is preferable that the conventional general heat-dissipating sheet is a low-hardness layer 43 and a high-hardness layer 42 having a higher hardness than the low-hardness layer 43 is laminated on one surface thereof.
In the heat dissipation sheet 40 having the multilayer structure, the high hardness layer 42 is preferably on the inner bottom surface 21S side of the housing 20.
By making the heat-dissipating sheet 40 have the above-mentioned multilayer structure, the heat-dissipating sheet 40 is prevented from being bent when the air vent 41 is opened, and the opening work of the air vent 41 is facilitated. In addition, since the high hardness layer 42 is on the inner bottom surface 21S side of the housing 20, the heat radiation sheet 40 is less bent on the inner bottom surface 21S side of the housing 20, so the inner bottom surface 21S of the housing 20 and the heat radiation sheet 40 are reduced. Excess air is prevented from entering between the two.

The hardness of the high hardness layer 42 is preferably durometer A50 to 95, for example.
The hardness of the low hardness layer 43 is preferably, for example, Asker C5-30.
As a method of laminating the high hardness layer 42 and the low hardness layer 43, for example, after placing a sheet to be the high hardness layer 42 in the mold, the material of the low hardness layer 43 is injected into the mold and cured. The method is preferred.

  As described above, according to the present invention, it is possible to provide a reactor 1 that can improve heat dissipation at low cost and a method for manufacturing the same.

DESCRIPTION OF SYMBOLS 1 Reactor 10 Reactor main body 11 Reactor core 12 Coil 12A Convex part 20 Case 21 Bottom part 21S Inner bottom face 22 Side part 22 Coil 30,40 Heat radiation sheet 31,41 Vent hole 42 High hardness layer 43 Low hardness layer

Claims (6)

A reactor body including a reactor core and a coil wound around the reactor core;
A housing for housing the reactor body;
A reactor comprising a heat dissipation sheet interposed between the casing and the coil of the reactor body and compressed in the thickness direction by the coil;
The heat dissipation sheet has a multilayer structure of a high hardness layer having a relatively high hardness and a low hardness layer having a relatively low hardness, and is formed through the heat dissipation sheet in the thickness direction, and is compressed by the coil. A reactor having at least one vent hole blocked by.   The reactor according to claim 1, wherein the heat dissipation sheet is installed with the high hardness layer as an inner bottom surface side of the housing.   The reactor according to claim 1 or 2, wherein the hardness of the high hardness layer is durometer A50 to 95, and the hardness of the low hardness layer is Asker C5 to 30. The reactor according to any one of claims 1 to 3, wherein an uncompressed hole diameter d (µm) of the vent hole satisfies the following formula (X).
0.1 (μm) ≦ d (μm) ≦ (t × A) / 100 (μm) (X)
(In the formula, t represents the thickness (μm) of the heat dissipation sheet before compression, and A represents the compression ratio (%) of the heat dissipation sheet by the coil.) The reactor in any one of Claims 1-4 in which the arithmetic mean roughness Ra of the mounting surface of the said thermal radiation sheet satisfies the following formula (Y) in the said housing | casing.
5 (μm) ≦ Ra (μm) ≦ t / 2 (μm) (Y)
(In the formula, t is the thickness (μm) of the heat dissipation sheet before compression.) A reactor body including a reactor core and a coil wound around the reactor core;
A housing for housing the reactor body;
A reactor manufacturing method comprising a heat dissipation sheet interposed between the casing and the coil of the reactor body,
The housing has a multilayer structure of a high hardness layer having a relatively high hardness and a low hardness layer having a relatively low hardness, and has at least one vent hole formed so as to penetrate in the thickness direction. A step of placing the sheet;
And a step of attaching the reactor main body in the housing such that the heat radiating sheet is compressed in the thickness direction by the coil and the air hole is closed by the compression.

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