JP2004281974A - Heat radiation structure of electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat radiation structure by which the heat radiation effect is improved with a radiating route shortened, high airtightness is secured and downsizing is attained when packaged. <P>SOLUTION: A substrate 3 wherein an electronic component 2 having a radiating face 2A and a second face at an opposite side of the radiating face is provided in a protrudent manner is fixed to a case 10 of thermal conductivity. Within the case a supporting wall 18 oppositely arranged on an inner peripheral face of the case at a position estranged from the inner peripheral face is integrally provided with the case. A springy fixture 20 is mounted in a state of elastic deformation between the supporting wall and the second face of the electronic component to make the radiating face 2A come closely into contact with the inner peripheral face of the case 10. As the electronic component is directly brought into contact with the case facing the air, the radiating route is shortened. As the fixture is retained in space between the case and the supporting wall and does not protrude from an opening end face of the case, it does not interfere with a lid when the opening end face of the case is covered by the lid, and airtightness is secured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat dissipation structure for an electronic component, and more particularly to a heat dissipation structure for an electronic component having airtightness.
[0002]
[Prior art]
As shown in FIG. 6, a conventional heat radiating structure for electronic components includes a plurality of electronic components 102 protruding from a substrate 103 in a line, for example, a heat-generating transistor having one end face formed of a heat conductive casing. In a state where the fixing member 120 is opposed to the inner surface of the body 110, one of the legs of the fixture 120 having a U-shaped cross section having a spring property is brought into contact with the outer surface of the housing 110, and the other leg of the fixing member 120 is attached to the electronic component 102. The one end surface of the electronic component 102 is brought into close contact with the inner surface of the housing 110 by being brought into contact with the other end surface opposite to the one end surface side and straddling the wall of the housing 110 by the elastic force of the fixture 120 so as to straddle the wall of the housing 110. The heat of the electronic component 102 was released to the housing 110. (For example, see Patent Document 1)
[0003]
According to another conventional heat dissipating structure for electronic components, as shown in FIG. 7, one end surface of a plurality of heat generating electronic components 202 protruding from the substrate 203 in a line is provided with a heat conductive screw. In a state where the plurality of electronic components 202 are sandwiched between the housing 210 and the holding plate 218, the holding plate 218 is arranged along the other end surface side of the electronic component 202 so as to face the inner surface of the housing 210 in which the hole 210 a is formed. In addition, the holding plate 218 is fixed to the housing 210 with the screw 220, and the electronic component 202 is brought into close contact with the housing 210 and the holding plate 218 by urging the holding plate 218 in the housing direction. (See, for example, Patent Document 1).
[0004]
In another conventional heat dissipation structure for electronic components, as shown in FIG. 8, a guide plate 318 is slightly separated from the inner surface of a bracket 317 on the inner surface side of a case 310 made of metal and integrally provided with fins 313. A groove G is provided between the inner surface of the housing and the guide plate 318, and one end surface of the electronic component 302 is arranged to face the inner surface side of the guide plate 318 to form a U-shaped section having a spring property. One leg of the fixture 320 is inserted into the groove G, and the other leg straddles the end face of the guide plate 318 and abuts on the other end face of the electronic component 302 so that the electronic component 302 is brought into contact with the guide plate 318. To achieve heat dissipation. After the electronic component 302 is set, the housing 310 is covered with the lid 331, and the fixing tool 320 is pressed by the lid 331. (For example, see Patent Document 2).
[Patent Document 1]
JP-A-1-165655 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-183575
[Problems to be solved by the invention]
However, in the conventional heat dissipation structure of an electronic component shown in FIG. 6, for example, when the upper end surface of the housing 110 is covered, the fixture 120 is attached across the outer surface and the inner surface of the housing 110. Therefore, a discontinuous step is formed by the upper end surface of the housing 110 and the fixture 120, and it is difficult to realize an airtight structure. Further, in the conventional heat radiating structure of an electronic component shown in FIG. 7, not only is it troublesome to hold the electronic component 202 in the housing 210, but also a screw hole 210 a that allows the screw 220 to pass through the housing 210 must be formed. , Resulting in impaired airtightness.
[0006]
Further, in the conventional heat radiating structure of the electronic component shown in FIG. 8, since the electronic component 302 is in close contact with the inner surface of the guide plate 318, the heat radiating path is from the guide plate 318 to the bracket 317 supporting the guide plate 318, the casing. The fin 313 is indispensable because the body 310 becomes complicated and long, and the heat radiation effect from the housing 310 in contact with the outside air is not sufficient.
[0007]
Therefore, an object of the present invention is to provide a heat radiation structure for an electronic component that can shorten the heat radiation path to enhance the heat radiation effect of the electronic component, has high airtightness, and can be downsized when packaged. And
[0008]
[Means for Solving the Problems]
Means for Solving the Problems In order to achieve the above object, the present invention provides a heat conductive housing for housing a substrate on which an electronic component having a heat radiating surface and a second surface opposite to the heat radiating surface is provided, and the electronic component A heat-dissipating structure for an electronic component, comprising: a fixture having a spring property for disposing the electronic component facing the housing; and a position fixed to the housing and separated from an inner peripheral surface of the housing. A support wall portion is provided so as to face the inner peripheral surface, and the heat radiating surface of the electronic component is directly opposed to the inner peripheral surface of the housing, and the electronic component faces the inner peripheral surface. The fixture is interposed between the support wall and the second surface of the electronic component while being elastically deformed, so that the casing has a cylinder having an opening at one end and an opening at the other end. A first lid and a second lid are fixed to the one end opening and the other end opening, respectively, so that the housing, the first lid and the A package structure is formed by the two lids, and the fixing tool dissipates heat of the electronic component held in the space between the housing and the support wall without engaging with the opening end face of the opening facing the lid. Offering structure.
[0009]
Here, the substrate has a first substrate surface facing the first lid and a second substrate surface facing the second lid on a side opposite to the first substrate surface, and is biased toward the one end opening. It is preferable that the support wall is located on the second substrate surface side. Further, it is preferable that the substrate is disposed in the housing so as to have the same shape and substantially the same size as the inside contour of the one end opening.
[0010]
Further, it is preferable that endless sealing materials are respectively mounted between the one end opening and the first lid, and between the other end opening and the second lid. Further, a heat radiation grease is applied or a heat radiation sheet is disposed on a heat radiation surface of the electronic component, and the heat radiation surface is in close contact with the inner peripheral surface of the housing via the heat radiation grease or the heat radiation sheet. Is preferred. Further, it is preferable that a radiation fin is integrally provided on the outer peripheral surface side of the housing.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
A heat dissipation structure of an electronic component according to a first embodiment of the present invention will be described with reference to FIGS. The cooling structure 1 according to the present embodiment is, for example, in the form of a board package as an on-board engine ignition control device, and is a space sealed by a housing 10, a first lid 31, and a second lid 32 (FIG. 5). Is defined.
[0012]
The housing 10 is a tubular body having a rectangular cross section having a first opening end 11 and a second opening end 12, and a heat-dissipating rib or fin 13 is integrally provided on the outer peripheral surface side. A plurality of attachments for fixing the first lid 31 and the second lid 32 to the first opening end 11 and the second opening end 12 at the corners of the housing 10 with screws (not shown), respectively. The parts 14 and 15 are provided integrally. A board mounting portion 16 (FIG. 5) in which a female screw is screwed protrudes from the inner peripheral surface of the housing 10 at a position close to the first opening end 11. The casing 10 is cast from a material that can exhibit desired rigidity and has a high thermal conductivity, such as an Al—Mg alloy or copper.
[0013]
A plurality of brackets 17 protrude inward from the inner peripheral surface of the housing 10, and a U-shaped support wall 18 is fixed to the brackets 17 integrally. The support wall portion 18 is located on the opposite side to the first opening end 11 with respect to the substrate mounting portion 16, and is separated from the inner peripheral surface of the housing 10 and extends parallel to the wall surface of the housing 10. A gap S is defined. The support wall 18 is formed integrally with the housing 10.
[0014]
The board 3 is formed in a rectangular shape having substantially the same dimensions as the inside contour of the opening of the first opening end 11 and is fixed on the board mounting section 16 by screws 19 (FIG. 5). Therefore, the substrate 3 is fixed to the housing 10 at a position biased toward the first opening end 11 in the housing 10, that is, at a position near the first lid 31. A plurality of heat-producing electronic components 2 to be cooled have a heat radiating surface 2A and a second surface 2B that is opposite to the heat radiating surface and is parallel to the heat radiating surface. (See FIG. 5). When the substrate 3 is set on the housing 10, the heat radiating surface 2 </ b> A of the electronic component 2 is in a positional relationship directly facing the inner peripheral surface of the housing 10.
[0015]
In order to increase the thermal conductivity from the electronic component 2 to the housing 10, heat radiation grease is applied to the heat radiation surface 2A. Even if the inner peripheral surface of the housing 10 is not smooth but rough, the heat radiation grease is buried in the concave portions of the rough surface, so that the adhesion between the electronic component 2 and the housing 10 can be improved. It can be used in the as-cast state after casting, so that the inner peripheral surface machining can be omitted.
[0016]
In order to press the electronic component 2 against the inner peripheral surface of the housing 10 and make the electronic component 2 come into close contact with the inner peripheral surface, the fixing tool 20 is provided in the gap S between the support wall portion 18 and the inner peripheral surface. Are interposed from the second opening end 12 side of the housing 10 while being elastically deformed between the second surfaces 2B. The fixing members 20 are made of a material having a spring property, for example, SUS, and three sets are provided so as to face each side of the U-shaped support wall portion 18 in plan view. As shown in FIG. 5, each fixture 20 extends in the direction in which the support wall 18 extends, and has a base 21 having a folded portion that is locked to the top surface 18A (FIG. 4) of the support wall 18. And a plurality of U-shaped elastic portions 23 extending independently of each other from the base 21 in parallel with each other and abutting on the second surface 2B of each electronic component 2.
[0017]
When the insertion of the fixture 20 into the gap S is completed, the folded portion of the base 21 abuts on the top surface 18A of the support wall 18, and one arm of the U-shaped elastic portion 23 presses the vertical of the support wall 18. Then, since the other arm presses the second surface 2B of the electronic component 2, the heat radiation surface 2A of the electronic component 2 is securely adhered to the inner peripheral surface of the housing 10 via the heat radiation grease. In this state, the U-shaped elastic portion 23 of the fixing device 20 is not locked so as to straddle between the front surface and the back surface of the second opening end, but the space between the housing 10 and the support wall portion 18. Since it is only held at S, a part of the fixing tool 18 is not exposed on the opening end surface of the second opening end portion 12 and no step occurs.
[0018]
A packing (O-ring) 33 as an endless sealing material that follows the shape of the opening end surface of the first opening end 11 and a packing (O-ring) 34 as an endless sealing material that follows the shape of the opening end surface of the second opening end 12 are provided. Can be The first lid 31 abuts on the first opening end 11 of the housing 10 via the packing 33 and is fixed by screws via the lid mounting portion 14, and the second lid 32 is It comes into contact with the second opening end 12 via a packing 34, and is fixed by screws via a lid mounting portion 15. Thus, the hermeticity of the package defined by the first lid 31, the second lid 32, and the housing 10 is ensured. At this time, as described above, since a part of the fixture 18 is not exposed on the opening end surface of the second opening end portion 12, the opening end surface is kept smooth without any step, and airtightness can be improved.
[0019]
The U-shaped elastic portions 23 are provided separately from each other so as to reliably apply a pressing force to each electronic component 2. When the U-shaped elastic portion is provided integrally as in the case of the base portion 21, for example, a central electronic component of a plurality of electronic components arranged in a row may be strongly pressed, and pressing on the electronic components at both ends may be insufficient. Therefore, the U-shaped elastic portion 23 is provided independently for each electronic component.
[0020]
The heat radiation structure of the electronic component according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. For example, in the above-described embodiment, the heat radiation grease is applied to the heat radiation surface 2A of the electronic component 2, but a heat radiation sheet may be stuck instead of the heat radiation grease. Further, if a predetermined surface accuracy can be obtained by machining the inner peripheral surface of the housing 10, a heat radiation grease or a heat radiation sheet is unnecessary.
[0021]
Further, in the present embodiment, the electronic component 2 is directly in close contact with the housing 10 facing the outside air, and has a very good heat dissipation structure with a short heat dissipation path. Therefore, the fins 13 may be omitted. As a result, the external dimensions can be reduced and a small package can be obtained.
[0022]
Further, in the above-described embodiment, the support wall 18 is formed integrally with the housing 10, but the support wall 18 may be manufactured separately from the housing 10 and fixed to the housing 10 with screws or the like. In addition, various materials can be applied to the housing as long as it has predetermined mechanical strength and thermal conductivity. Further, the substrate does not necessarily have to have substantially the same dimensions and the same shape as the contour inside the opening of the first opening 11, and the substrate mounting portion extending from the housing is provided at an appropriate place different from the corner, and A substrate having a size smaller than the opening area of one opening may be attached.
[0023]
【The invention's effect】
According to the heat dissipating structure of the electronic component according to the first aspect, the support wall portion fixed to the housing and opposed to the inner peripheral surface at a position separated from the inner peripheral surface of the housing is provided in the housing. The heat radiating surface of the electronic component is disposed directly opposite to the inner peripheral surface of the housing, and a fixture for pressing the electronic component in the inner peripheral surface direction and closely contacting the electronic component is provided between the support wall and the second surface of the electronic component. The electronic components come into direct contact with the housing because they are elastically deformed, and the heat generated by the electronic components is directly transmitted to the housing facing the outside air, and the heat is radiated without passing through the complicated heat radiating route. Can be shortened, the heat radiation effect can be enhanced, and the production of a complicated heat radiation path becomes unnecessary, and the production cost can be reduced.
[0024]
The housing has a cylindrical shape having an opening at one end and an opening at the other end. A first lid and a second lid are fixed to the opening at one end and the opening at the other end, respectively. The first lid and the second lid form a package structure, and the fixture is held in the space between the housing and the support wall without being locked to the opening end face of the housing opening facing the lid. Therefore, a part of the fixture does not intervene between the housing and the first lid and between the housing and the second lid, and thus the airtightness between the opening and the lid can be ensured. Therefore, it is possible to provide an electronic device package having both good heat dissipation and high airtightness and waterproofness.
[0025]
According to the heat dissipating structure for an electronic component of the present invention, the substrate has a first substrate surface facing the first lid and a second substrate surface facing the second lid on a side opposite to the first substrate surface. The support wall is disposed so as to be biased toward the opening, and the support wall is disposed on the second substrate surface side. Therefore, the fixture can be disposed on the second substrate surface side to hold the electronic component. .
[0026]
According to the heat dissipating structure for an electronic component according to the third aspect, the substrate is disposed in the housing in the same shape having substantially the same dimensions as the inside contour of the opening at one end, so that the opening area of the opening at one end is maximized. Therefore, the degree of freedom in the layout of electronic elements on the substrate can be increased, and the size of the entire package can be reduced.
[0027]
According to the electronic component heat dissipation structure of the present invention, the endless sealing material is provided between the one end opening of the housing and the first lid, and between the other end opening of the housing and the second lid. Since it is mounted, the airtightness between the housing and the lid can be further enhanced.
[0028]
According to the heat radiating structure of the electronic component according to the fifth aspect, the heat radiating grease is applied or the heat radiating sheet is disposed on the heat radiating surface of the electronic component that is in close contact with the inner peripheral surface of the housing. Even when the inner peripheral surface is not smooth, the adhesiveness between the electronic component and the housing can be maintained, so that the housing can be used as cast and the inner peripheral surface machining can be omitted.
[0029]
According to the heat dissipation structure of the electronic component according to the sixth aspect, since the heat dissipation fins are integrally provided on the outer peripheral surface side of the housing, heat dissipation from the housing is promoted.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional schematic front view of a package adopting an electronic component heat dissipation structure according to an embodiment of the present invention, with a lid removed.
FIG. 2 is a plan view of the package of FIG. 1 as viewed from the direction of arrow II of FIG. 1;
FIG. 3 is a plan view of the substrate package of FIG. 1 as viewed from the direction of arrow III of FIG. 1;
FIG. 4 is a partial perspective view showing a heat radiation structure of the electronic component in the package of FIG. 1 according to the embodiment of the present invention;
FIG. 5 is an exploded perspective view of a package adopting a heat radiation structure of an electronic component according to an embodiment of the present invention.
FIG. 6 is a partial perspective view showing a heat dissipation structure of a conventional electronic component.
FIG. 7 is a partial perspective view showing a heat dissipation structure of another conventional electronic component.
FIG. 8 is a partial perspective view showing another conventional heat dissipation structure of an electronic component.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Heat dissipation structure of electronic component 2 ... Electronic component 2A ... Heat dissipation surface 2B ... 2nd surface 3 ... Substrate 10 ... Case 11 ... 1st open end part 12 ··· Second opening end 13 ··· Fins 14 and 15 ··· Lid mounting part 16 ··· Board mounting part 18 ··· Supporting wall part 20 ··· Fixing element 31 ··· First lid body 32 ... Second lids 33, 34 ... Endless packing

Claims (6)

A housing having thermal conductivity for accommodating a substrate on which an electronic component having a heat radiating surface and a second surface opposite to the heat radiating surface is provided, and having a spring property for disposing the electronic component facing the housing; In a heat dissipation structure of an electronic component having a fixture,
In the housing, a support wall portion fixed to the housing and disposed opposite to the inner peripheral surface at a position separated from the inner peripheral surface of the housing is provided,
The heat dissipating surface of the electronic component is directly opposed to the inner peripheral surface of the housing, and the fixture is attached to the support wall in order to press and adhere the electronic component in the inner peripheral surface direction. The electronic component is interposed between the second surfaces while being elastically deformed,
The housing has a cylindrical shape having an opening at one end and an opening at the other end, and a first lid and a second lid are fixed to the opening at the one end and the opening at the other end, respectively. And a package structure including the first lid and the second lid, wherein the fixing member is provided between the housing and the support wall without being locked to an opening end surface of an opening facing the lid. A heat dissipation structure for electronic components, which is held in a space. The substrate has a first substrate surface facing the first lid and a second substrate surface facing the second lid on a side opposite to the first substrate surface, and is disposed so as to be biased to the one end opening. 2. The heat radiating structure for an electronic component according to claim 1, wherein the support wall is located on the second substrate surface side. 3. The heat dissipation structure for an electronic component according to claim 2, wherein the substrate has the same shape and substantially the same size as an inner contour of the opening of the one end opening, and is disposed in the housing. 4. An endless sealing material is provided between the one end opening and the first lid, and between the other end opening and the second lid, respectively. A heat dissipation structure for an electronic component according to any one of the preceding claims. A heat radiation grease is applied or a heat radiation sheet is disposed on a heat radiation surface of the electronic component, and the heat radiation surface is in close contact with an inner peripheral surface of the housing via the heat radiation grease or the heat radiation sheet. A heat dissipation structure for an electronic component according to claim 1. 6. The heat radiating structure for an electronic component according to claim 1, wherein a heat radiating fin is integrally provided on an outer peripheral surface side of the housing.

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