JP5556531B2 - Electronic module mounting structure - Google Patents

Description

  The present invention relates to an electronic module mounting structure in which an electronic module in which a heat generating element is mounted on a heat radiating plate is mounted on a heat radiating body.

  Conventionally, as an electronic module mounting structure of this type, an electronic module including a heat generating element and a heat-dissipating heat dissipation plate having a heat generating element mounted on one surface side is opposed to the other surface of the heat dissipating plate. There has been proposed one that is attached to the one surface side of the heat dissipating body so as to transmit heat from the heat dissipating plate to the heat dissipating body (see, for example, Patent Document 1).

JP 2002-134669 A

  However, in recent years, further improvement in heat dissipation has been demanded as the power of heating elements is increased. In particular, when the temperature rises due to heat generation of the heating element or an increase in environmental temperature, the amount of heat generated increases, so high heat dissipation is required.

  The present invention has been made in view of the above problems, and in an electronic module mounting structure in which an electronic module in which a heat generating element is mounted on a heat radiating plate is mounted on a heat radiating body, heat dissipation at the time of temperature increase is improved. The purpose is to let you.

  In order to achieve the above-mentioned object, the present inventor first sets the opposing surfaces of the heat dissipation plate and the heat dissipating member of the electronic module to have a concavo-convex shape in order to improve heat dissipation from the electronic module to the heat radiating member. It was considered that if the meshing contact was made, the contact area would be larger and the heat dissipation would be improved compared to the case where both surfaces were flat. The invention described in claim 1 was created by paying attention to such an idea.

That is, in the first aspect of the present invention, the one surface (2c) of the radiator (2) includes the radiator-side convex portion (2a) protruding toward the other surface (20b) of the radiator plate (20) and the heat dissipation. It is made into the uneven | corrugated shape which consists of the recessed part (2b) between body side convex parts (2a),
The other surface (20b) of the heat radiating plate (20) is a concave portion (21) between the heat radiating plate side convex portion (21) protruding toward the one surface (2c) of the heat radiating body ( 2 ) and the heat radiating plate side convex portion (21). 22) and the heat-radiating-side convex portion (2a) enters the concave portion (22) between the heat-radiating plate-side convex portions (21) so that the both convex portions (2a, 21) are engaged with each other. And
The bottom surface of the recess (22) between the bottom surface of the heat sink side concave portion (2b) of the one surface (2c) of the heat radiator (2) and the heat sink plate side convex portion (21) of the other surface (20b) of the heat sink plate (20). A receiving portion (5) for fastening the heat radiating plate (20) and the heat radiating body (2) is interposed between the radiating plate and the linear expansion coefficient of the radiating plate (20) than the linear expansion coefficient of the receiving portion (5). The coefficient and the coefficient of linear expansion of the radiator (2) are larger,
The heat radiating plate (20), the receiving portion (5), the screw (3) passing through the receiving portion (5) and reaching the inside of the heat radiating body (2), the heat radiating plate (20), the receiving portion (5), And the part of one surface (2c) of the said heat radiating body (2) which the said heat radiating body (2) is fastened and is contacting the said receiving part (5), and the part of the other surface (20b) of the said heat radiating plate (20) Is fixed by the fastening force of the screw (3),
When the receiving portion (5), the heat radiating plate (20), and the heat radiating body (2) are thermally expanded, the distance (a1) between the tip surface of the heat radiating plate side convex portion (21) and the bottom surface of the heat radiating body side concave portion (2b). ), The distance (a2) between the front end surface of the radiator-side convex portion (2a) and the bottom surface of the concave portion (22) between the radiator plate-side convex portion (21), and the radiator-side convex portion (2a) and the The distance (a3) between the side surfaces facing each other with the heat radiating plate side convex portion (21) is reduced.

  According to this, the other surface (20b) of the heat radiating plate (20) and the one surface (2c) of the heat radiating body (2) facing each other have the above-mentioned concavo-convex shape, and the heat radiating side convex portion (2a) 21) Since the convex portions (2a, 21) are engaged with each other by entering the concave portion (22) between the convex portions (2), each convex portion (2a, 21) and the concave portion (2b, 22) on the other side. Since a heat radiation path is formed not only between the bottom surfaces of the two but also between the opposing side surfaces of the convex portions (2a, 21), the heat radiation area can be increased.

  Moreover, even if unevenness is provided on both opposing surfaces (20b, 2c) of the heat radiating plate (20) and the heat radiating body (2) in this way and the both concavo-convex shapes are engaged, the unevenness on the heat radiating plate (20) side is provided. There is a considerable gap between the projections and depressions on the side of the radiator (2). This gap becomes an air layer, which greatly impairs heat dissipation.

  Therefore, in consideration of this point, in the present invention, the linear expansion coefficient of the heat radiating plate (20) and the linear expansion coefficient of the heat radiating body (2) are made larger than the linear expansion coefficient of the receiving portion (5). Thus, when the receiving portion (5), the heat radiating plate (20), and the heat radiating body (2) are thermally expanded, the front end surface of the heat radiating plate side convex portion (21) and the bottom surface of the heat radiating body side concave portion (2b) Distance, distance between the front end surface of the radiator-side convex portion (2a) and the bottom surface of the recess (22) between the radiator plate-side convex portion (21), and the radiator-side convex portion (2a) and the radiator plate-side convex portion (21 The distance between the side surfaces facing each other is reduced.

  As described above, according to the present invention, when the temperature rises, each part is thermally expanded, and the gap between the unevenness on the heat radiating plate (20) side and the unevenness on the heat radiator (2) side is reduced. Therefore, according to this invention, since the layer of the air which inhibits heat dissipation at the time of temperature rising can be shrunk | reduced, heat dissipation can be improved.

Here, as in the invention according to claim 2, in the electronic module mounting structure according to claim 1, the bottom surface of the radiator-side recess (2b) and the one surface (2c) of the radiator (2) are flush with each other. The bottom surface of the heat sink plate side recess (22) and the other surface (20b) of the heat sink plate (20) are flush with each other, and the receiving portion (5) is flush with the heat sink side recess (2b). Between one surface (2c) of the heat radiating body (2) and the concave portion (22) between the convex portions (21) on the heat radiating plate and the other surface (20b) of the heat radiating plate (20) which is flush with each other. If it is provided, it is easy to provide the receiving portion (5) between the two surfaces, and the radiator (2) and the radiator plate (20) can be easily fastened.

  In the invention according to claim 3, in the electronic module mounting structure according to claim 1 or 2, when the receiving portion (5), the heat radiating plate (20), and the heat radiating body (2) are thermally expanded. The distances (a1, a2, a3) are 0, and the two concavo-convex shapes are in contact with each other. Thus, the air layer which inhibits heat dissipation can be eliminated by the contact of the two concavo-convex shapes as a whole. Therefore, the heat dissipation can be significantly improved.

  In the case of each of the above means, ideally, due to thermal expansion, the timing when the tip surface of the heat radiation plate side convex portion (21) contacts the bottom surface of the concave portion (2b) between the heat radiator side convex portions (2a), It is desirable that the tip of the radiator-side convex portion (2a) contacts the bottom surface of the concave portion (22) between the heat-radiating plate-side convex portions (21) at the same time.

  However, in each of the above means, at the time of thermal expansion, the radiator-side convex portion (2a) having a larger linear expansion coefficient has a higher degree of expansion in the protruding direction than the heat-radiating plate-side convex portion (21) having a smaller linear expansion coefficient. large.

  Therefore, in consideration of this point, in Claim 4, in the electronic module mounting structure according to any one of Claims 1 to 3, the front end surface of the heat radiating plate side convex portion (21) and the heat radiating member side convex portion. The distance (a1) between the bottom surface of the recess (2b) between (2a) is the distance between the tip surface of the radiator-side convex portion (2a) and the bottom surface of the recess (22) between the radiator plate-side convex portions (21) ( It is smaller than a2).

  According to this, the timing at which the tip surface of the heat radiating plate side convex portion (21) contacts the bottom surface of the concave portion (2b) between the heat radiator side convex portions (2a) and the tip surface of the heat radiator side convex portion (2a) are This is preferable in that the timing of contacting the bottom surface of the concave portion (22) between the heat radiating plate side convex portions (21) is made as much as possible.

  Here, in the invention according to claim 5, in the electronic module mounting structure according to any one of claims 1 to 5, the heating element (10) is on the side opposite to the heat dissipation plate (20). , Electrically connected to the connector (4) for taking out the signal from the heating element (10) to the outside, the heat radiating plate (20) is configured as a lid of the connector (4) covering the heating element (10) It is characterized by being made.

  According to this, since the heat generating element (10) connected to the connector (4) is covered with the heat radiating plate (20), the heat radiating element (10) is removed from the connector (4). ) Can be prevented.

  Further, in the electronic module mounting structure according to any one of claims 1 to 5, as in the invention according to claim 6, the heating element (10) is disposed on the wiring board on the heat sink (11). (12) The electronic components (13) are sequentially laminated, and the laminate is sealed with the mold resin (14), and a part of the heat sink (11) is exposed from the mold resin (14). The portion of the heat sink (11) exposed from the mold resin (14) can be in contact with one surface of the heat radiating plate (20).

  Moreover, in invention of Claim 7, in the attachment structure of the electronic module as described in any one of Claim 1 thru | or 6, the cross-sectional shape along the protrusion direction protrudes in the heat sink side convex part (2a). The trapezoidal shape is narrowed toward the tip side, and the heat radiating plate side convex portion (21) has a trapezoidal shape whose cross-sectional shape along the protruding direction is narrowed toward the protruding tip side. It is said.

  According to this, even when warpage occurs due to the difference in thermal expansion coefficient between the radiator (2) and the radiator plate (20) at the time of temperature rise, the convex portions (2a, 21) having a trapezoidal cross section are engaged with each other. Therefore, it is possible to efficiently secure the heat radiation path without interference between the convex portions.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a schematic sectional drawing which shows the attachment structure of the electronic module which concerns on 1st Embodiment of this invention. It is a figure which shows each unevenness | corrugation in the one surface of a heat radiator, and the other surface of a heat sink, (a) is a schematic plan view of one surface of a heat radiator, (b) is a schematic plan view of the other surface of a heat sink. It is a schematic sectional drawing which expands and shows the meshing part of both the unevenness | corrugations of a heat sink and a heat radiator. It is a schematic sectional drawing which shows the principal part of the attachment structure of the electronic module which concerns on 2nd Embodiment of this invention. It is a schematic plan view which shows each unevenness | corrugation in the one surface of the heat radiator which concerns on 3rd Embodiment of this invention, and the other surface of a heat sink.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, parts that are the same or equivalent to each other are given the same reference numerals in the drawings for the sake of simplicity.

(First embodiment)
FIG. 1 is a diagram showing a schematic cross-sectional configuration of an electronic module 1 mounting structure in which an electronic module 1 according to a first embodiment of the present invention is mounted on a radiator 2. The electronic module 1 is an electronic device mounted on a vehicle of an automatic engine, for example, and the heat radiator 2 in that case is a block body such as a valve body of the engine.

  The electronic module 1 includes a heating element 10 that generates heat during driving and a plate-like heat dissipation plate 20 made of a metal such as a metal having thermal conductivity, and is disposed on one surface (upper surface in FIG. 1) 20a of the heat dissipation plate 20. The heating element 10 is mounted. Examples of the heating element 10 include an IC chip having a power element, a mold IC, and the like.

  In the present embodiment, the heating element 10 is a mold IC, and a wiring board 12 and an electronic component 13 are sequentially laminated on a heat sink 11, and a laminated body formed by laminating these is sealed with a mold resin 14, and a heat sink 11 is exposed from the mold resin 14.

  Here, the heat sink 11 is a plate made of a material such as a metal having excellent heat dissipation such as aluminum, copper, and molybdenum. The wiring substrate 12 is a ceramic substrate, for example, and is mounted on the heat sink 11 and fixed by adhesion or the like.

  The electronic component 13 is a component that generates a large amount of heat, such as a power transistor element, and a passive element such as a resistor or a capacitor is also included in the electronic component 13 as necessary. These electronic components 13 are electrically connected to the wiring board 12 by, for example, wire bonding, flip chip, conductive adhesive, solder, or the like.

  The heat generating element 10 includes a lead 15 made of a conductive material such as copper, like a general mold IC. The lead 15 is sealed with a mold resin 14 and the outer lead is molded. It protrudes from the resin 14.

  Here, the lead 15 and the wiring substrate 12 are electrically connected within the mold resin 14 by a bonding wire 16 such as gold or aluminum. A signal from the wiring board 12 is taken out of the mold resin 14 by the outer lead.

  The mold resin 14 is made of a mold material such as a general epoxy resin, and is molded by, for example, a transfer mold method. The surface of the heat sink 11 opposite to the mounting surface of the wiring board 12 is exposed from the mold resin 14, and the surface of the heat sink 11 exposed from the mold resin 14 is in contact with one surface of the heat radiating plate 20. Yes.

  Here, the heat generating element 10 is fixed to the heat radiating plate 20 via the bracket 17. Specifically, the bracket 17 is integrated as a part of the heat generating element 10 by the mold resin 14, similarly to the lead 15, and the portion of the bracket 17 protruding from the mold resin 14 is connected via the screw 3. Fastened to the heat dissipation plate 20.

  Further, as shown in FIG. 1, the heating element 10 is electrically connected to the connector 4 on the side opposite to the heat dissipation plate 20. The connector 4 is a member for taking out a signal from the heating element 10 to the outside (for example, an external circuit such as an ECU of a vehicle), and is configured as a resin molded product having a terminal terminal and the like built therein.

  Here, the outer lead of the lead 15 of the heating element 10 is electrically connected to a terminal terminal (not shown) of the connector 4 by welding or soldering. Thereby, the heating element 10 of the electronic module 1 is electrically connected to the connector 4, and the heating element 10 and the outside are electrically connected via the connector 4.

  Moreover, in this embodiment, the heat radiating plate 20 is comprised as a cover of the said connector 4 attached to the connector 4 so that the heat generating element 10 may be covered. Here, for fixing the heat radiating plate 20 and the connector 4, well-known joining means such as screw tightening and system connection can be employed.

As described above, the electronic module 1 of the present embodiment includes the heat generating element 10 and the heat radiating plate 20 on which the heat generating element 10 is mounted on the one surface 20a side. In the present embodiment, the electronic module 1, one surface 2c is attached to the other surface (lower surface in FIG. 1) 20 b and is disposed so as to face the one surface of the heat radiating member 2 of the radiating plate 20 .

  The heat generated in the heat generating element 10 is transmitted from the heat radiating plate 20 to the heat radiating body 2 to radiate heat. Specifically, heat generated in the electronic component 13 and the wiring board 12 of the heating element 10 is radiated from the heat sink 11 to the heat radiating body 2 through the heat radiating plate 20.

  Here, as described above, the heat radiating body 2 is a block body such as a valve body, but one surface 2c of the heat radiating body 2 is directed toward the other surface 20b of the heat radiating plate 20 as shown in FIG. It is made into the uneven | corrugated shape which consists of the recessed part 2b dented compared with the heat sink side convex part 2a between the heat sink side convex part 2a which protrudes, and the heat radiator side convex part 2a. If it says further, the bottom face of the recessed part 2b between the heat sink side convex parts 2a will correspond to the base surface of the heat radiator side convex part 2a. That is, the bottom surface of the recess 2b in the present embodiment is continuous with the one surface 2c of the radiator 2.

Further, the receiving portion 5 is interposed between the one surface 2 c of the radiator 2 and the other surface 20 b of the heat radiating plate 20. Specifically, the receiving part 5 is interposed between the bottom surface of the heat sink side concave portion 2b of the one surface 2c of the heat radiator 2 and the bottom surface of the heat sink plate side concave portion 22 described later of the other surface 20b of the heat sink plate 20. It supports the heat radiating plate 20. The heat radiating plate 20 and the heat radiating body 2 are fastened through the receiving portion 5.

Specifically, the receiving part 5 is cylindrical, and the screw 3 passes through the bracket 17, the heat radiating plate 20, and the receiving part 5 and reaches the inside of the heat radiating body 2. Here, by forming a female screw that is screw-coupled to the screw 3 in the hollow portion of the receiving portion 5 and inside the radiator 2, these respective portions are fastened via the screw 3 .

  Moreover, in this embodiment, the unevenness | corrugation corresponding to the uneven | corrugated shape of the heat radiator 2 is formed in the site | part which opposes the uneven | corrugated shaped part in one surface 2c of the heat radiator 2 among the other surfaces 20b of the heat sink plate 20. FIG. That is, the unevenness of the heat dissipation plate 20 is a recess that is recessed as compared with the heat dissipation plate side convex portion 21 between the heat dissipation plate side convex portion 21 and the heat dissipation plate side convex portion 21 that protrudes toward the one surface 2c of the radiator 2. An uneven shape consisting of 22 is formed. If it says further, the bottom face of the recessed part 22 between the heat sink plate side convex parts 21 will correspond to the base face of the heat sink plate side convex part 21.

  That is, the bottom surface of the recess 22 in this embodiment is continuous with the other surface of the heat dissipation plate 20. The receiving portion 5 is provided between one surface 2c of the radiator 2 that is flush with the recess 2b and the other surface 20b of the radiator plate 20 that is flush with the recess 22. Thereby, it becomes easy to provide the receiving part 5 between the said both surfaces, and the fastening of the heat radiator 2 and the heat radiating plate 20 becomes easy.

  And the heat sink side convex part 2a of the heat sink 2 has penetrated into the recessed part 22 between the heat sink plate side convex parts 21 in the heat radiating plate 20, so that the heat radiator side convex part 2a and the heat sink plate side convex part 21 are formed. It is in a meshed state.

  Here, FIG. 2 is a diagram showing the irregularities on the one surface 2c of the heat radiating body 2 and the other surface 20b of the heat radiating plate 20. FIG. 2A is a schematic plan view of the one surface 2c of the heat radiating body 2, and FIG. 4 is a schematic plan view of the other surface 20b of the heat dissipation plate 20. FIG. In addition, in these FIG. 2, the receiving part 5 is also shown, and also in FIG.2 (b), the heat sink side convex part 2a in the state which the said both convex parts 2a and 21 engaged is shown with the broken line.

  As shown in FIG. 2, in the present embodiment, convex portions 2 a and 21 having a rectangular parallelepiped shape are provided on the one surface 2 c of the radiator 2 and the other surface 20 b of the radiator plate 20, respectively. In other words, on one surface 2c of the radiator 2, a plurality of rectangular parallelepiped radiator-side convex portions 2a are arranged in a direction perpendicular to the longitudinal direction with the longitudinal directions aligned. And between each heat sink side convex part 2a is made into the recessed part 2b (henceforth the heat radiator side recessed part 2b).

  On the other hand, on the other surface 20b of the heat radiating plate 20, a plurality of rectangular parallelepiped heat radiating plate-side convex portions 21 are arranged in a direction perpendicular to the longitudinal direction with the longitudinal directions aligned. And between each heat sink plate side convex part 21 is made into the recessed part 22 (henceforth the heat sink plate side recessed part 22).

  Then, as shown in FIG. 2B, the radiator-side convex portion 2a is engaged with the heat-radiating plate-side concave portion 22 so that the radiator-side convex portion 2a and the heat-radiating plate-side convex portion 21 are engaged with each other. . In addition, it is only necessary that the heat radiator 2 and the heat radiation plate 20 have irregularities so that the both convex portions 2a and 21 are engaged with each other, and it is of course not limited to the irregular shapes as shown in FIG. It is. For example, irregularities may be formed in an irregular island shape.

  As described above, in this embodiment, the other surface 20b of the heat radiating plate 20 and the one surface 2c of the heat radiating body 2 facing each other are formed in the above-described concavo-convex shape, and the heat radiating member side convex portion 2a enters the heat radiating plate side concave portion 22, Both convex parts 2a and 21 are in a state of being engaged with each other.

  Therefore, in this embodiment, a heat radiation path is formed not only between the respective convex portions 2a, 21 and the bottom surfaces of the counterpart concave portions 2b, 22, but also between the opposing side surfaces of the respective convex portions 2a, 21. Therefore, in this embodiment, compared with the case where the other surface 20b of the heat radiating plate 20 and the one surface 2c of the heat radiating body 2 are flat surfaces, the heat radiating area can be increased, and the heat radiation performance is improved.

  As described above, in the present embodiment, the heat radiating plate 20 and the heat radiating body 2 fastened through the receiving portion 5 are configured as the heat radiating members 2 and 20 that radiate the heat generated in the electronic module 1, The electric signal of the electronic module 1 does not flow.

  Here, in the case of the configuration as in the present embodiment, even if both the unevenness of the heat radiating plate 20 and the heat radiating body 2 are engaged, there is little difference between the unevenness on the heat radiating plate 20 side and the unevenness on the heat radiating body 2 side. A gap occurs. This gap is an air layer, which greatly impairs heat dissipation.

  Therefore, in the present embodiment, the heat radiating members 2, 20 and the receiving portion 5 have a large amount of generated heat and require a high heat radiating property at the time of temperature rise to be between the heat radiating plate 20 and the heat radiating body 2. In order to appropriately secure the heat radiation path, the relationship between the linear expansion coefficients of the respective parts 2, 5, and 20 is defined. This relationship will be described in more detail with reference to FIG. FIG. 3 is an enlarged schematic cross-sectional view showing a meshing portion of both the heat radiation plate 20 and the heat radiating body 2.

  That is, in this embodiment, the linear expansion coefficient of the heat radiating plate 20 is larger than the linear expansion coefficient of the receiving portion 5, and the linear expansion coefficient of the radiator 2 is larger than the linear expansion coefficient of the heat radiating plate 20. It is getting bigger. That is, for the linear expansion coefficient, the magnitude relationship of the receiving portion <the heat radiating plate <the heat radiating body is defined.

  As long as such a magnitude relationship is established, the material of each of the parts 2, 5, and 20 is not particularly limited. For example, in this embodiment, the receiving part 5 is made of SPCC made of carbon steel. The heat radiating plate 20 is made of copper, and the heat radiating body 2 is made of aluminum.

  And according to the relationship of such a linear expansion coefficient, at the time of temperature rising, that is, at the time of thermal expansion of each of the parts 2, 5, and 20, the receiving part 5 is the minimum for the degree of expansion of the three parties 2, 5, and 20. The heat radiating plate 20 is the middle, and the heat radiating body 2 is the largest. For example, the radiator 2 can be Al (linear expansion coefficient α = 23), the radiator plate 20 can be Cu (α = 17), and the receiving portion 5 can be SPCC (α = 11).

  Here, since the part of the one surface 2c of the heat radiating body 2 that is in contact with the receiving part 5 and the part of the other surface 20b of the heat radiating plate 20 are fixed by the fastening force, deformation due to expansion is substantially ignored. The Therefore, at the time of the thermal expansion, with respect to the heat radiation path between the heat radiator 2 and the heat radiation plate 20, the degree of expansion of the heat radiator side convex portion 2a and the heat radiation plate side convex portion 21 is dominant.

  And in this embodiment, the expansion degree of the heat sink side convex part 2a is the expansion degree of the heat radiating plate side convex part 21 in the protrusion direction of each convex part 2a, 21 and the direction orthogonal to it from the relationship of the said linear expansion coefficient. Is bigger than.

  Then, at the time of the thermal expansion, a distance a1 between the tip surface of the radiator plate-side convex portion 21 and the bottom surface of the radiator-side concave portion 2b, a distance a2 between the tip surface of the radiator-side convex portion 2a and the bottom surface of the radiator plate-side concave portion 22, and The distance a3 between the side surfaces of the radiator-side convex portion 2a and the heat-radiating plate-side convex portion 21 facing each other is reduced. These distances a1, a2, and a3 are shown in FIG.

  As described above, according to the electronic module mounting structure of the present embodiment, the heat dissipation area between the heat dissipation plate 20 and the heat dissipating body 2 of the electronic module 1 can be increased by the above-described concavity and convexity configuration. The gap between the concaves and convexes can be reduced by the relationship between the linear expansion coefficients of the respective parts 2, 5 and 20. Therefore, according to this embodiment, the heat dissipation at the time of temperature rise can be improved.

  In addition, as will be described with reference to FIG. 3, in the present embodiment, ideally, the tip surface of the heat radiating plate-side convex portion 21 radiates heat due to the thermal expansion of each of the portions 2, 5, 20 when the temperature rises. It is desirable that the timing at which the bottom surface of the body-side recess 2b comes into contact with the timing at which the tip surface of the radiator-side projection 2a contacts the bottom surface of the radiation plate-side recess 22 is the same.

  That is, due to the thermal expansion, the distance a1 between the front end surface of the heat radiation plate side convex portion 21 and the bottom surface of the heat radiator side concave portion 2b shown in FIG. 3, the front end surface of the heat radiator side convex portion 2a, and the bottom surface of the heat radiation plate side concave portion 22 It is ideal that the distance a2 to be zero at the same time.

  However, in this embodiment, at the time of thermal expansion, the radiator-side convex portion 2a having a large linear expansion coefficient has a higher degree of expansion in the protruding direction than the heat-radiating plate-side convex portion 21 having a small linear expansion coefficient.

  Therefore, for example, when the distances a1 and a2 are the same, at the time of thermal expansion, the tip of the radiator-side convex portion 2a having a large linear expansion coefficient is more than the heat-dissipating plate-side convex portion 21 having a small linear expansion coefficient. It quickly comes into contact with the bottom surface of the recess on the other side. That is, at that time, a gap remains between the heat radiation plate side convex portion 21 and the bottom surface of the heat radiator side concave portion 2b. Thereafter, when the temperature is further increased and both are thermally expanded, the tips of the heat-radiating-side convex portions 2 a that are in contact with each other are pressed against the bottom surface of the heat-dissipating plate-side concave portion 22 so as to separate the heat-radiating body 2 and the heat-dissipating plate 20. In such a state, if the temperature is continuously raised until the tip of the heat radiation plate side convex portion 21 comes into contact with the bottom surface of the heat radiator side concave portion 2b, an excessive load is generated on the receiving portion, which is not preferable.

  Therefore, in the present embodiment, as a preferable form, the distance a1 between the front end surface of the heat radiating plate side convex portion 21 and the bottom surface of the heat radiating member side concave portion 2b is set to the distance between the front end surface of the heat radiator side convex portion 2a and the bottom surface of the heat radiating plate side concave portion 22. It is desirable that the distance is smaller than the distance a2. According to this, at the time of thermal expansion, it is possible to make the timing when both the convex portions 2a and 21 contact the mating concave portions 2b and 22 as much as possible. In this case, since an air layer that inhibits heat dissipation does not exist between the both end surfaces and the bottom surface, the heat dissipation at the time of temperature rise can be remarkably improved.

  Moreover, in this embodiment, at the time of thermal expansion, the contact between the distal end surface of the heat radiation plate side convex portion 21 and the bottom surface of the heat radiator side concave portion 2b during the distance a1, and the front end of the heat radiator side convex portion 2a between the distance a2. It is preferable that the contact between the side surface of the heat radiation plate side convex portion 21 and the side surface of the heat radiator side convex portion 2a within the distance a3 is realized earlier than the contact between the surface and the bottom surface of the heat radiation plate side concave portion 22.

  At the time of thermal expansion, it is ideal that all the facing surfaces are simultaneously in contact between the distances a1 to a3. Here, for example, when the contact between the opposing surfaces during the distance a1 and the contact between the opposing surfaces during the distance a2 are earlier than the contact between the side surfaces during the distance a3, the distance a3 Further, as described above, each convex portion expands so as to push up the mating member and damages the mating member between the distance a1 and the distance a2. There is a risk of giving.

  In that respect, such a problem can be avoided by making the contact between the side surfaces between the distances a3 faster than the contact between the opposing surfaces between the distances a1 and a2. Furthermore, if all the facing surfaces are in contact with each other at the same time between the distances a1 to a3 during thermal expansion, there will be no air layer that impedes heat dissipation between both irregularities. Can contribute greatly. In addition, about this, by appropriately setting the protrusion height of each unevenness on the heat radiating plate 20 side and the heat radiating body 2 side, the width of each convex part and the concave part, each distance a1 to a3, and further each linear expansion coefficient. Is possible.

  Further, in the mounting structure of the present embodiment shown in FIG. 1, the heat generating element 10 is attached to the connector 4 and the heat radiating plate 20 is attached to the connector 4 and the heat generating element 10. Assembling is completed by fastening the radiator 2.

  Here, as described above, in the present embodiment, the heat radiating plate 20 is configured as a lid of the connector 4. In this case, the heat generating element 10 is shielded by the heat radiating plate 20 in the space in the connector 4 by attaching the heat generating element 10 to the connector 4 and further attaching the heat radiating plate 20 to the connector 4 during the assembly.

  Therefore, when the heat radiating plate 20 is subsequently attached to the heat radiating body 2, the heat radiating element 10 can be prevented from falling off from the connector 4 by the heat radiating plate 20, so that improvement in handleability in the attachment is expected.

(Second Embodiment)
FIG. 4 is a schematic cross-sectional view showing the main part of the mounting structure for an electronic module according to the second embodiment of the present invention, where (a) shows a state before warpage and (b) shows a state after warpage. ing. The present embodiment is different from the first embodiment in that the uneven shape on both sides between one surface of the radiator 2 and the other surface of the heat radiating plate 20 is modified, and this difference is mainly described. And

  As shown in FIG. 4, in the present embodiment, the radiator-side convex portion 2a has a trapezoidal shape in which the cross-sectional shape along the projecting direction is narrowed toward the projecting tip side, The section 21 has a trapezoidal shape in which the cross-sectional shape along the protruding direction is narrowed toward the protruding tip side. Both the convex portions 2a and 21 have a trapezoidal cross section corresponding to mesh with each other.

  According to this, when the temperature rises, as shown in FIG. 4B, even when warpage occurs due to the difference in thermal expansion coefficient between the radiator 2 and the radiator plate 20, the taper in the convex portions 2 a and 21 is mutually. It is expected that the protrusions 2a and 21 are less likely to interfere with each other due to the trapezoidal side surface, that is, the trapezoidal side surface, and as a result, it is expected to easily secure a heat dissipation path efficiently.

(Third embodiment)
FIG. 5: is a schematic sectional drawing which shows the principal part of the attachment structure of the electronic module which concerns on 3rd Embodiment of this invention. 5A and 5B are diagrams showing irregularities on one surface of the heat radiating body 2 and the other surface of the heat radiating plate 20. FIG. 5A is a schematic plan view of one surface of the heat radiating body 2, and FIG. FIG. In FIG. 5, the receiving portion 5 is also shown, and further, in FIG. 5B, the radiator-side convex portion 2 a in a state where the both convex portions 2 a and 21 are engaged is indicated by a broken line.

  The irregularities on one surface of the radiator 2 and the other surface of the radiator plate 20 are not limited to FIG. 2 described above. For example, the convex portions 2a and 21 are columnarly arranged in a staggered manner. The part recessed from the convex parts 2a and 21 may be the concave parts 2b and 22. Furthermore, it goes without saying that various uneven shapes other than those shown in FIGS. 2 and 5 are possible.

(Other embodiments)
In addition, as a fastening method of the thermal radiation plate 20 and the thermal radiation body 2 via the receiving part 5, it is not limited to the method using the said screw 3, Various known fastening means are possible.

  Moreover, in the said embodiment, although the thermal radiation plate 20 of the electronic module 1 was comprised as a lid | cover of the connector 4 which covers the heat generating element 10, the said thermal radiation plate 20 is limited to the lid | cover of the connector 4. FIG. Of course not.

  Further, the heating element 10 is not limited to the mold IC as long as it generates heat during driving and requires heat dissipation, and may be a bare chip or an electronic component other than a semiconductor element.

DESCRIPTION OF SYMBOLS 1 Electronic module 2 Heat sink 2a Heat sink side convex part 2b Heat sink side concave part 4 Connector 5 Receiving part 10 Heating element 11 Heat sink 12 Wiring board 13 Electronic component 14 Mold resin 20 Heat sink plate 21 Heat sink plate side convex part 22 Heat sink plate side concave part a2 Heat dissipation Distance between the front end surface of the body side convex portion and the bottom surface of the heat sink plate side concave portion a3 Distance between the side surfaces facing each other of the heat radiator side convex portion and the heat sink plate side convex portion

Claims (7)

An electronic module (1) comprising a heat generating element (10) and a heat-dissipating heat dissipation plate (20) having the heat generating element (10) mounted on one surface (20a) side, the one surface (2c) It is attached to the one surface ( 2c ) side of the radiator (2) provided to face the other surface (20b) of the radiator plate (20), and heat from the radiator plate (20) is transferred to the radiator (20). 2) In the electronic module mounting structure that is communicated to
One surface (2c) of the heat radiating body (2) has a heat sink side convex portion (2a) protruding toward the other surface (20b) of the heat radiating plate (20) and a concave portion between the heat radiator side convex portion (2a) ( 2b) is an uneven shape,
The other surface (20b) of the heat radiating plate (20) is between the heat radiating plate side convex portion (21) projecting toward the one surface (2c) of the heat radiating body ( 2 ) and the heat radiating plate side convex portion (21). While forming the uneven | corrugated shape which consists of a recessed part (22), the said heat sink side convex part (2a) enters into the recessed part (22) between the said heat sink plate side convex part (21), and the said both convex part (2a, 21) Are in a state of being engaged,
Of the one surface (2c) of the radiator (2), a recess (between the bottom surface of the radiator side recess (2b) and the other surface (20b) of the radiator plate (20 ) between the convex portions (21) of the radiator plate (20). 22), a receiving portion (5) for fastening the heat radiating plate (20) and the heat radiating body (2) is interposed between the bottom surface of the heat radiating plate (20),
The linear expansion coefficient of the heat radiating plate (20) and the linear expansion coefficient of the heat radiating body (2) are larger than the linear expansion coefficient of the receiving part (5),
The heat radiating plate (20), the receiving portion (5), the screw (3) passing through the receiving portion (5) and reaching the inside of the heat radiating body (2), the heat radiating plate (20), the receiving portion (5), And the part of one surface (2c) of the said heat radiating body (2) which the said heat radiating body (2) is fastened and is contacting the said receiving part (5), and the part of the other surface (20b) of the said heat radiating plate (20) Is fixed by the fastening force of the screw (3),
When the receiving portion (5), the heat radiating plate (20), and the heat radiating body (2) are thermally expanded, a tip surface of the heat radiating plate side convex portion (21) and a bottom surface of the heat radiating body side concave portion (2b) Distance (a1), the distance (a2) between the tip surface of the radiator-side convex portion (2a) and the bottom surface of the recess (22) between the radiator plate-side convex portion (21), and the radiator-side convex portion ( 2a) and the heat radiation plate side convex portion (21), the distance (a3) between the side surfaces facing each other is reduced. The bottom surface of the heat sink side recess (2b) and one surface (2c) of the heat radiator (2) are flush with each other.
The bottom surface of the heat radiation plate side recess (22) and the other surface (20b) of the heat radiation plate (20) are flush with each other.
The receiving portion (5) has a recess (22) and a surface between the one surface (2c) of the radiator (2) and the radiator plate-side convex portion (21) which are flush with the radiator-side concave portion (2b). 2. The electronic module mounting structure according to claim 1, wherein the electronic module mounting structure is provided between the heat dissipation plate and the other surface (20 b). Before Symbol receiving unit (5), said heat radiating plate (20), and wherein when the heat radiating body (2) is thermally expanded, the respective distances (a1, a2, a3) said two uneven across the contact becomes 0 The electronic module mounting structure according to claim 1, wherein the electronic module mounting structure is provided. And it is increased in linear expansion coefficient before Symbol radiating plate (20) the radiator than the linear expansion coefficient of the (2),
The distance (a1) between the front end surface of the heat radiating plate side convex portion (21) and the bottom surface of the concave portion (2b) between the heat radiating body side convex portion (2a) is equal to the front end surface of the heat radiating body side convex portion (2a). The electronic module mounting structure according to any one of claims 1 to 3, wherein the mounting structure is smaller than a distance (a2) between a bottom surface of the concave portion (22) between the heat radiation plate side convex portions (21). Before SL heating element (10), said the heat radiating plate (20) on the opposite side, are electrically connected to a connector (4) for taking out a signal from the heating element (10) to the outside,
5. The electronic module according to claim 1, wherein the heat radiating plate is configured as a cover of the connector covering the heat generating element. Mounting structure. Before SL heating element (10), the wiring board on the heat sink (11) (12), are sequentially laminated electronic component (13), as well as sealed by these laminate molding resin (14), the heat sink ( 11) is partly exposed from the mold resin (14),
The part of the heat sink (11) exposed from the mold resin (14) is in contact with one surface (20a) of the heat radiating plate (20). The electronic module mounting structure described. Before SL radiator side protrusion (2a), the cross-sectional shape along its projecting direction is a narrowed trapezoidal shape toward the protruding tip end side,
The heat dissipation plate side convex portion (21) has a trapezoidal shape in which a cross-sectional shape along the protruding direction is narrowed toward the protruding tip side. The electronic module mounting structure described.

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