JP2012227374A - Heat radiation structure of electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat radiation structure of an electronic apparatus which reduces a burden of the manufacturing operation by providing the heat radiation structure and reduces the manufacturing cost.SOLUTION: A heat radiation structure has a heat sink 4 fixed to the exterior of a case 3 housing a semiconductor element 2 that is a heating element; and rivets 5 serving as fixing means which fixes the heat sink 4 to the case 3. The fixing means contacts with the heating element in the case 3 thereby transmitting heat generated in the heating element to the heat sink 4. The fixing means is formed by at least one of aluminium and copper.

Description

  The present invention relates to a heat dissipation structure for an electronic device, and more particularly, to a heat dissipation structure for effectively radiating heat-generating elements housed in a case.

  An electronic device is used in a state in which various components such as an electronic circuit are stored in a case (housing). As a component housed in the case, an element having a high calorific value such as a semiconductor element may be used. The exothermic element may be destroyed due to an abnormally high temperature by causing the element to generate heat, or may adversely affect peripheral components. For this reason, a measure for heat dissipation is required for an element having a high heat generation amount.

  In general, the elements housed in the case are dissipated by attaching a heat sink to the elements in the case. However, since the temperature in the sealed case increases with time, the efficiency of heat dissipation by the heat sink in the case gradually deteriorates, resulting in an increase in the temperature of the element.

  In this regard, for example, Patent Document 1 proposes a heat dissipation device in which an opening is provided on one surface constituting the case and a heat sink is attached so as to close the opening from the outside of the case. The element in the case can be radiated to the outside of the case by being fixed to the heat sink at the opening.

JP 2000-244157 A

  However, in the structure in which the heat sink is attached to the opening provided in the case, there is a concern that dust or water may enter through a slight gap generated between the heat sink and the opening. Intrusion of dust or water in electronic equipment may cause insulation failure of internal circuits. Therefore, a structure for attaching a heat sink to the opening portion requires a structure for dustproofing and waterproofing to prevent intrusion of dust and water.

  Furthermore, in the structure in which the heat sink is attached to the opening, it is necessary to prepare a case provided with the opening. For this reason, the standard case cannot be used as it is, and an additional process for forming the opening is required, or a special product is used. As described above, according to the conventional technique, there is a problem in that the burden of the manufacturing work and the increase in the manufacturing cost due to the addition of the configuration accompanying the provision of the heat dissipation structure and the addition of the processing steps are problematic.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a heat dissipation structure for an electronic device that can reduce the burden of manufacturing work and reduce the manufacturing cost by providing the heat dissipation structure.

  In order to solve the above-described problems and achieve the object, the present invention includes a heat sink fixed to the outside of a case that houses a heating element, and a fixing unit that fixes the heat sink to the case. The fixing means is configured to be able to propagate heat generated by the heating element to the heat sink by contacting the heating element in the case.

  According to the present invention, since the opening for attaching the heat sink is not necessary in the case of the heat dissipation structure, it is not necessary to perform dustproof and waterproof treatment between the heat sink and the case. Further, a processing step for providing an opening in the case is not necessary. The heat dissipation structure can be easily manufactured because it can have a simple configuration using a fixing means such as a rivet. As a case, a standard case can be used without using a special product. Thereby, it becomes possible to reduce the burden of the manufacturing work by providing the heat dissipation structure and to reduce the manufacturing cost.

FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of a heat dissipation structure for an electronic device according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a heat dissipation structure when a wide gap semiconductor element is used. FIG. 3 is a schematic cross-sectional view illustrating a heat dissipation structure when a wide gap semiconductor element is used. FIG. 4 is a schematic cross-sectional view illustrating a schematic configuration of the heat dissipation structure of the electronic device according to the first embodiment of the present invention.

  Embodiments of a heat dissipation structure for an electronic device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of a heat dissipation structure for an electronic device according to a first embodiment of the present invention. The electronic device 1 includes a heat dissipation structure including a heat sink 4 and a rivet 5, a case 3, and an electronic circuit including a semiconductor element 2 that is a heating element. In the present embodiment, only elements necessary for the description of the present invention in the electronic device 1 are illustrated, and elements unnecessary for the description of the present invention are not illustrated.

  The semiconductor element 2 is assumed to be one of the elements that generate the highest amount of heat during driving in the electronic circuit inside the case 3. The case 3 is a housing of the electronic device 1 and houses an electronic circuit including the semiconductor element 2. The case 3 may be configured using any material such as a metal material or a resin material.

  The heat sink 4 is fixed to the outside of the case 3, for example, on a plate member 6 forming one surface constituting the case 3 by using rivets 5 as fixing means. The semiconductor element 2 is disposed in contact with the rivet 5 inside the case 3. The semiconductor element 2 and the heat sink 4 are connected by a rivet 5 with a plate member 6 interposed therebetween. The rivet 5 is made of a material having high thermal conductivity, for example, aluminum or copper.

  The rivet 5 receives heat generated in the semiconductor element 2 from a portion in contact with the semiconductor element 2 and propagates it to the heat sink 4. The heat propagated to the heat sink 4 through the rivet 5 is released from the heat sink 4 to the outside of the case 3. In this way, the heat dissipation structure releases the heat generated in the semiconductor element 2 to the outside of the case 3. Note that the number of semiconductor elements 2 to be radiated by the radiating structure may be any number.

  If heat radiation of the semiconductor element 2 is performed only inside the case 3, effective heat radiation of the semiconductor element 2 may be difficult due to an increase in temperature inside the case 3. The heat dissipation structure according to the present embodiment enables the heat from the semiconductor element 2 to be released to the outside of the case 3, thereby suppressing an increase in the temperature inside the case 3 as a whole, and the effective use of the semiconductor element 2. Heat dissipation is possible.

  According to the present embodiment, the heat dissipation structure adopts a configuration in which heat is propagated from the inside of the case 3 to the outside by the rivet 5, so that an opening for attaching the heat sink 4 to the case 3 becomes unnecessary. Therefore, the intrusion of dust and water due to the provision of the heat dissipation structure can be greatly suppressed as compared with the case where the opening is provided in the case 3. According to the present embodiment, there is no need for a processing step of providing an opening in the case 3 for the heat dissipation structure, and dustproofing and waterproofing such as sealing in the heat dissipation structure.

  Since the heat dissipation structure has a simple configuration using the rivet 5 as a fixing means, it can be easily manufactured. As the case 3, a standard case can be used without using a special product. Thereby, it becomes possible to reduce the burden of the manufacturing work by providing the heat dissipation structure and to reduce the manufacturing cost.

  By using the rivet 5 composed of a member having high thermal conductivity, the heat dissipation structure promotes thermal conduction from the semiconductor element 2 to the heat sink 4, and enables effective heat dissipation of the semiconductor element 2. Furthermore, the heat dissipation structure may be applied to a portion of the semiconductor element 2 that contacts the rivet 5 with a silicon compound for reducing the contact thermal resistance. In addition, the heat dissipation structure may be provided with a buffer material having thermal conductivity between the semiconductor element 2 and the rivet 5. Accordingly, the heat dissipation structure promotes heat conduction from the semiconductor element 2 to the rivet 5, and enables effective heat dissipation of the semiconductor element 2.

  Although two rivets 5 are shown in FIG. 1, any number of rivets 5 may be used. The heat dissipation structure can promote heat conduction from the semiconductor element 2 to the heat sink 4 as the number of rivets 5 is increased. When a plurality of rivets 5 are provided, each rivet 5 is disposed outside the case 3 so as to fix the heat sink 4 and be in contact with the semiconductor element 2 inside the case 3.

  When the rivet 5 is used as the fixing means, the heat sink 4 can be firmly fixed to the case 3. Since the heat sink 4 is provided outside the case 3, for example, it may be susceptible to wind and rain, external impact, or the like. The heat dissipating structure enables the heat sink 4 to be firmly fixed by the rivet 5, thereby allowing heat dissipation through the rivet 5 to be continued for a long period of time.

  The fixing means may be a rivet 5 as long as the heat of the semiconductor element 2 can be transmitted to the heat sink 4 by fixing the heat sink 4 outside the case 3 and contacting the semiconductor element 2 inside the case 3. Not limited to cases. The fixing means may be a screw, for example. When bolts and nuts are used as fixing means, since the bolts and nuts have many flat portions, effective heat dissipation can be achieved by ensuring a wide contact area with the semiconductor element 2.

  The heat dissipation structure may be configured to contact the rivet 5 with the semiconductor element 2 or may be configured to contact the rivet 5 with an electronic circuit including the semiconductor element 2. In this case, the heat dissipation structure can effectively dissipate heat by propagating heat generated in the electronic circuit, which is a heating element, to the heat sink 4 via the rivet 5.

  If the surface of the semiconductor element 2 that contacts the rivet 5, that is, the surface facing the plate member 6, is the heat dissipation surface, the larger the number of rivets 5, the smaller the area of the heat dissipation surface per rivet 5 and the heat dissipation effect. Becomes higher. Here, a comparison between the case of using a normal semiconductor element using Si and the case of using a wide gap semiconductor element using SiC or the like will be described.

  FIG. 2 is a schematic cross-sectional view illustrating a heat dissipation structure when a wide gap semiconductor element is used. In general, the wide gap semiconductor element 7 has a large dielectric breakdown electric field and can handle a large current density. Therefore, the wide gap semiconductor element 7 is downsized as compared with a normal semiconductor element. The heat dissipating structure should have the same heat dissipating surface area per rivet 5 even if the number of rivets 5 is reduced in accordance with the reduction of the heat dissipating surface due to the application of the downsized wide gap semiconductor element 7. Thus, an equivalent heat dissipation effect can be obtained. As for the wide gap semiconductor element 7, even if the heat dissipation structure is simpler than that of a normal semiconductor element, the same heat dissipation effect can be obtained.

  As shown in FIG. 3, if the number of rivets 5 is the same as that of a normal semiconductor element with respect to the wide gap semiconductor element 8, the area of the heat radiating surface per rivet 5 is reduced. A high heat dissipation effect can be obtained.

  In the heat dissipation structure, when the contact pressure between the semiconductor element 2 and the rivet 5 decreases due to variations in the component size and assembly of the electronic device 1, the heat dissipation efficiency increases because the contact thermal resistance between the semiconductor element 2 and the rivet 5 increases. There is concern about the decline. In order to allow the semiconductor element 2 to dissipate a certain amount of heat, it is possible to take measures such as application of a silicon compound or the intervention of a thermally conductive buffer material.

  The wide gap semiconductor elements 7 and 8 have high temperature resistance as compared with a normal semiconductor element using Si. When wide-gap semiconductor elements 7 and 8 are used, even if there is a decrease in the heat dissipation effect due to variations in contact pressure, there is a margin in the permissible range for the increase in junction temperature due to the effect compared to normal semiconductor elements. It becomes. Therefore, when the wide gap semiconductor elements 7 and 8 are used, compared to the case of using a normal semiconductor element, it is less susceptible to the influence of variations in contact pressure, and the highly reliable electronic device 1 can be configured. It becomes possible.

Embodiment 2. FIG.
FIG. 4 is a schematic cross-sectional view illustrating a schematic configuration of the heat dissipation structure of the electronic device according to the second embodiment of the present invention. The electronic device 11 includes a heat dissipation structure including the heat sink 4, the rivet 5, and the heat dissipation plate 13, a case 3, and an electronic circuit including a plurality of semiconductor elements 12 that are heating elements. The same parts as those in the first embodiment are denoted by the same reference numerals, and repeated description will be omitted as appropriate. Note that the number of semiconductor elements 12 to be radiated by the radiating structure may be any number.

  The heat radiating plate 13 is fixed inside the case 3 by rivets 5 as fixing means. The heat radiating plate 13 is made of a material having high thermal conductivity, for example, aluminum or copper. The rivet 5 is attached through the heat radiating plate 13. The semiconductor element 12 is disposed so as to contact the heat radiating plate 13 or the rivet 5 and the heat radiating plate 13. The semiconductor element 12 and the heat sink 4 are connected by a rivet 5 with the heat radiating plate 13 and the plate member 6 interposed therebetween.

  The heat generated in the semiconductor element 12 propagates to the rivet 5 directly or through the heat radiating plate 13, and further propagates from the rivet 5 to the heat sink 4. The heat propagated to the heat sink 4 through the rivet 5 is released from the heat sink 4 to the outside of the case 3. In this way, the heat dissipation structure releases the heat generated in the semiconductor element 12 to the outside of the case 3.

  According to the present embodiment, by providing the heat dissipation plate 13 in the heat dissipation structure, the heat of the semiconductor element 12 can be efficiently propagated to the heatsink 4, and more efficient heat dissipation is possible.

  As described above, the heat dissipation structure for an electronic device according to the present invention is suitable for heat dissipation of an electronic device including a semiconductor element.

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Semiconductor element 3 Case 4 Heat sink 5 Rivet 6 Plate member 7, 8 Wide gap semiconductor element 11 Electronic device 12 Semiconductor element 13 Heat sink

Claims (6)

A heat sink fixed outside the case for storing the heating element;
Fixing means for fixing the heat sink to the case,
The heat dissipating structure for an electronic device according to claim 1, wherein the fixing means is capable of propagating heat generated in the heat generating element to the heat sink by contacting the heat generating element in the case. A heat sink fixed inside the case by the fixing means;
The heat dissipation structure for an electronic device according to claim 1, wherein the heat dissipation plate is in contact with the heating element.   3. The heat dissipation structure for an electronic device according to claim 1, wherein the fixing unit is configured using at least one of aluminum and copper.   The heat dissipating structure for an electronic device according to claim 1, wherein the fixing means is a rivet.   5. The heat dissipation structure for an electronic device according to claim 1, wherein the heating element is a semiconductor element. 6.   6. The heat dissipation structure for an electronic device according to claim 5, wherein the semiconductor element is a wide gap semiconductor element.

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