JP3941704B2 - Heat dissipation structure for electronic components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat dissipation structure for an electronic component in which heat of the electronic component is transmitted to a heat radiating portion to be dissipated.
[0002]
[Prior art]
In an electronic device configured by housing a circuit board on which an electronic component is mounted, for example, in a metal casing, heat from a heat generating electronic component such as a power transistor is transmitted to itself or other electronic components. In order not to adversely affect, the heat is radiated from the outer wall of the housing. As the heat dissipation structure at that time, the tongue piece formed by cutting and raising the casing, and the tongue formed by cutting and raising the metal inner cover that is thermally connected to the casing It is known that heat of a heat generating component is transmitted to a housing via both tongue pieces to radiate heat by pressing the portion so as to overlap the heat generating component (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-233982
[Problems to be solved by the invention]
However, in the conventional heat dissipation structure, since the heat transfer tongue piece is pressed against the heat dissipation surface of the electronic component without any gaps, high dimensional accuracy is required for the assembly of each part. In addition, since excessive stress acts on the electronic component, there is a problem that the structure must be able to withstand the stress.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a heat dissipation structure for an electronic component that can perform efficient heat dissipation without applying excessive stress to the electronic component.
[0006]
[Means for Solving the Problems]
In the heat dissipation structure for an electronic component according to the first aspect of the present invention, heat of the electronic component is transmitted to the heat dissipation portion through two or more heat transfer blocks having good thermal conductivity in order, and heat dissipation is performed. However, the heat transfer blocks are thermally connected by the fitting structure of the concave grooves and the ridges. In this case, the wall surfaces of the concave grooves and the ridges contact each other between the heat transfer blocks to transfer heat, so that the pressure on the wall surfaces is canceled in each heat transfer block, and extra stress acts on the electronic components and the like. There is nothing. Also, by increasing the number of grooves and ridges, the contact area can be increased as compared with the case where contact is made on one flat surface, so that the heat transfer efficiency and thus the heat dissipation efficiency can be increased. .
[0007]
Furthermore, the heat transfer block can move in the direction in which the groove and the ridge extend, and also in the depth direction of the groove, a clearance is provided between the bottom of the groove and the tip of the ridge. By providing, the shift movement between the heat transfer blocks becomes possible. Therefore, since a slight positional shift between the heat transfer blocks can be absorbed, high dimensional accuracy of each part in assembly is not necessary.
[0008]
[0009]
[0010]
[0011]
[0012]
Then, the grooves and projections are provided extending radially from the center portion of the heat transfer block. According to this, since the coefficient of thermal expansion is different between the heat transfer blocks, even when the degree of expansion between the heat transfer blocks is different at the time of use, by forming the grooves and ridges radially extending, It becomes possible to absorb the difference in the degree of expansion by sliding between the two. In other words, it is possible to use materials having different coefficients of thermal expansion between the heat transfer blocks.
[0013]
Further, at this time, as in the invention of claim 2 , the radially extending concave grooves and ridges are formed so that the number on the outer peripheral side is larger than the inner peripheral side of the heat transfer block, and the number is A ring-shaped groove can be formed in the changing portion. According to this, it is possible to ensure an appropriate width of the concave grooves and ridges on the inner peripheral side of the heat transfer block, and even when the degree of expansion between the heat transfer blocks differs as described above, the ring By providing the groove, the protrusions can be prevented from interfering with each other.
[0014]
The electronic component referred to in the present invention is not only a single component but also a hybrid integrated circuit (multi-chip circuit) in which a plurality of chips are mounted on a wiring board (for example, a multilayer wiring board made of thermoplastic resin manufactured by batch heat pressing). Chip module). Further, in this case, in a module based on a metal, the metal base can also be used as one heat transfer block. In a monolithic IC, a wafer such as silicon is used as a heat transfer block, fine irregularities are formed by wafer processing technology, and the heat transfer block combined therewith can be formed by photoetching similar to printed circuit board pattern formation. As a material of the heat transfer block, not only a metal such as aluminum but also a ceramic having good thermal conductivity may be used. Furthermore, the heat transfer block is not limited to a rectangular block shape, and may be in various shapes such as a plate shape.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, actual施例embodying the present invention will be described with reference to the drawings.
Also not a, the basic configuration of the electronic apparatus 1, described with reference to FIG. The Figure 1, electronic equipment shows a configuration of a main part of the (electronic circuit unit) 1 schematically.
[0016]
Here, the electronic device 1 is configured by disposing a printed circuit board 3 in a housing 2. An electronic component 4 such as a power transistor having a large calorific value is mounted almost at the center of the surface (the lower surface in the figure) of the printed circuit board 3. Although not shown, the printed circuit board 3 is mounted with various components in addition to the electronic component 4 to form an electronic circuit. Further, the housing 2 is a good metal for example aluminum thermal conductivity, the housing 2 of this is also functions as a heat radiating portion. A lid 2 a is provided on the upper surface opening of the housing 2.
[0017]
In the electronic device 1, the heat of the electronic component 4 is radiated from the outer wall surface of the housing 2 to the outside so that the heat generated by the electronic component 4 does not adversely affect itself or other electronic components. To be done . Heat radiation structure is provided as follows.
[0018]
That is, in this heat dissipation structure, a plurality of heat transfer blocks 5 and 6 (the first heat transfer block 5 and the second heat transfer block 5 are made of a metal material having good heat conductivity, such as aluminum (extruded product). (Referred to as heat transfer block 6). The heat of the electronic component 4 is transmitted to the wall surface of the housing 2 as a heat radiating section through the first heat transfer block 5 and the second heat transfer block 6 in this order.
[0019]
At this time, the first heat transfer block 5 is formed in a rectangular block shape as a whole, and the lower surface thereof extends in the front-rear direction in the figure, and a plurality of, in this case, three concave grooves 5a are formed relatively deeply. Has been. Accordingly, the portions other than the concave groove 5a are formed into four convex strips 5b that protrude downward, and the convex strips 5b and the concave grooves 5a are provided alternately (in a so-called comb shape) with substantially the same width. Will be. The upper surface of the first heat transfer block 5 is fixed to the lower surface (heat radiating surface) of the electronic component 4 by brazing, for example.
[0020]
On the other hand, the second heat transfer block 6 as a whole has a rectangular block shape slightly larger in the left-right direction in the drawing than the first heat transfer block 5, and the upper surface side extends in the front-rear direction in the drawing. Five convex strips 6b and four concave grooves 6a are formed alternately and with a width and depth (height) substantially equal to the convex strips 5b and concave grooves 5a. The lower surface of the second heat transfer block 6 is fixed to the inner bottom surface of the housing 2 by, for example, brazing.
[0021]
As a result, the first heat transfer block 5 and the second heat transfer block 6 are assembled by fitting the protrusion 5b into the groove 6a and the protrusion 6b into the groove 5a. Combined and thermally connected. In this case, there are gaps between the bottoms of the grooves 5a and 6a and the tips of the ridges 6b and 5b, and the walls of the grooves 5a and 6a and the ridges 6b and 5b are in contact with each other. It is like that. In addition, the contact surface between the heat transfer block 5,6 together, i.e. grooves 5a, 6a and projections 6b, the side wall surface of 5b, thermal conductivity and lubricity good liquid, for example, silicon grease (thermal grease) is It has been applied.
[0022]
In the above configuration, the heat of the electronic component 4 is transmitted to the housing 2 as the heat radiating part through the first and second heat transfer blocks 5 and 6 having good heat conductivity in order to radiate heat. However, at this time, between the heat transfer blocks 5 and 6, the wall surfaces of the concave grooves 5a and 6a and the ridges 6b and 5b are in contact with each other to transmit heat, so compared with the case where they are in contact with one flat surface. The contact area is remarkably increased, and high heat transfer efficiency and consequently heat dissipation efficiency can be obtained. At the same time, unlike the case where the heat transfer tongue piece is pressed against the heat radiating surface of the electronic component, the pressure acting on the wall surfaces of the concave grooves 5a, 6a and the ridges 6b, 5b is applied to the heat transfer blocks 5, 6 respectively. The electronic components 4 and the like are not subjected to excessive stress.
[0023]
The heat transfer blocks 5 and 6 can move relative to each other in the extending direction (front-rear direction) of the grooves 5a and 6a and the ridges 6b and 5b, and the depth direction (vertical direction) of the grooves 5a and 6a. ) Can also be displaced between the heat transfer blocks 5 and 6. Therefore, in order to bring the heat transfer tongue piece into close contact with the electronic component without any gap, a slight positional deviation between the heat transfer blocks 5 and 6 is required, unlike the configuration that requires high dimensional accuracy for the assembly of each part. Since it can absorb, the high dimensional accuracy of each part in an assembly | attachment becomes unnecessary. In addition, at this time, silicon grease having good thermal conductivity and lubricity is applied to the contact surface between the heat transfer blocks 5 and 6, so that heat can be efficiently transferred between the heat transfer blocks 5 and 6. The shift movement can be smoothed.
[0024]
As a result, such as a heat radiation structure of traditional, with high dimensional accuracy in assembling of the components required, those extra stress on the electronic components had to a structure capable of withstanding the stress to act and In contrast, while being able to perform efficient heat dissipation, it is possible to eliminate the need for applying excessive stress to the electronic component 4 and to eliminate the need for high dimensional accuracy for assembling each part. Can be obtained. In particular, the Ryoden'netsu blocks 5 and 6, by which the extrusion molding of aluminum, it is possible to obtain an advantage capable of performing their formation easily.
[0025]
In the above configuration , a single component is taken as an example of the electronic component 4, but the electronic component is a hybrid integrated circuit (multi-chip module) in which a plurality of chips including heat generating components are mounted on a wiring board. May be. As the wiring board, those made of thermosetting resin or ceramic are generally used. However, the present applicant includes, for example, polyether ether ketone (PEEK) resin, polyether imide (PE Products using multilayer wiring boards made of thermoplastic resin such as PEI resin have been developed. In this case, for example, a metal base module in which a multilayer wiring board is formed by laminating a large number of thermoplastic resin films having a conductive foil pattern formed on a metal base and collectively pressing the film. There is.
[0026]
In such a metal base module, a concave groove (and / or protrusion) is formed in advance in the metal base (for example, a shape equivalent to that of the first heat transfer block 5). It can be used as two heat transfer blocks. At this time, in order to prevent deformation of the groove or the ridge during hot pressing, the second heat transfer block or a metal block having a shape equivalent to the second heat transfer block is combined with the metal base to perform hot pressing. It is preferable.
[0027]
In the following, the actual施例 modifications and the present invention the heat transfer block, with reference respectively to FIGS. The electronic component 4 and the housing 2 (heat radiating portion), etc., are common with the basic configuration described above, for their common parts, the use in common reference numerals, and new illustration and detailed description , below, we describe the different points.
[0028]
FIG. 2 shows a modification of the heat transfer block . In this modified example , first, second, and third three heat transfer blocks 11, 12, and 13 are provided in order between the electronic component 4 and the inner bottom surface (heat radiating portion) of the housing 2. Among them, the first heat transfer block 11 has an upper surface fixed to the lower surface of the electronic component 4 by brazing, for example, and has three concave grooves 11a and four ridges extending in the front-rear direction in the front view on the lower surface side. 11b are alternately formed with the same width. The lower surface of the third heat transfer block 13 is fixed to the inner bottom surface of the housing 2 by brazing, for example, and five concave grooves 13a and six extending in the left-right direction in the front view are formed on the upper surface side. The ridges 13b are alternately formed with the same width.
[0029]
Then, the second heat transfer block 12 has five front surfaces extending in the front-rear direction on the upper surface side and fitted to the concave grooves 11a and the convex strips 11b of the first heat transfer block 11. Convex ridges 12b and four concave grooves 12a are formed, and at the same time, on the lower surface side thereof, extend in the left-right direction in the front view, and the concave grooves 13a and ridges 13b of the third heat transfer block 13 Five protruding ridges 12d and four recessed grooves 12c are formed to be fitted to each other.
[0030]
Thus, the first heat transfer block 11 and the second heat transfer block 12 are combined by fitting the convex strips 11b into the concave grooves 12a and the convex strips 12b into the concave grooves 11a, respectively. These wall surfaces are in contact with each other to transmit heat, and the second heat transfer block 12 and the third heat transfer block 13 have the protruding stripes 12d as the concave grooves 13a and the convex stripes 13b as the concave grooves 12c, respectively. They are assembled by fitting together so that their wall surfaces come into contact with each other and transfer heat.
[0031]
At this time, in this configuration , the direction in which the concave grooves 11a and 12a and the ridges 11b and 12b extend between the first and second heat transfer blocks 11 and 12 (the front-rear direction), and the second and third heat transfer The extending direction (left-right direction) of the concave grooves 12c, 13a and the ridges 12d, 13b between the blocks 12, 13 is different by 90 degrees. Moreover, these 1st-3rd heat-transfer blocks 11-13 are assembled | attached in the state which has the clearance gap also in the up-down direction as a whole.
[0032]
In addition, although the said heat-transfer block 11, 12, 13 can also be comprised from the material which has a good heat conductivity, for example, the extrusion molding product of aluminum, about the 2nd heat-transfer block 12, at this time, An upper half part and a lower half part can be formed separately, and they can be constituted by bonding them by brazing, for example. Similarly to the above basic configuration , for example, silicon grease is applied to the contact surfaces of the heat transfer blocks 11, 12, 13.
[0033]
In the above configuration, the heat of the electronic component 4 is transmitted to the housing 2 as the heat radiating section through the first, second, and third heat transfer blocks 11, 12, and 13 in order, and the heat is radiated. However, at this time, similarly to the above basic configuration , a large contact area between the heat transfer blocks 11, 12, and 13 can be obtained, so that high heat transfer efficiency and consequently heat dissipation efficiency can be obtained. No extra stress acts on 4 mag. And between the 1st heat transfer block 11 and the 3rd heat transfer block 13, it can mutually shift and move in any direction of front and back, right and left, and up and down via the 2nd heat transfer block 12. Therefore, the effect of absorbing the positional deviation can be made high.
[0034]
FIG. 3 shows another modification of the heat transfer block . In this example , similarly to the basic configuration described above, the heat of the electronic component 4 is transferred to the housing 2 (heat dissipating part) through the first heat transfer block 21 and the second heat transfer block 22 made of aluminum in order, for example. To dissipate heat. On the lower surface side of the first heat transfer block 21, a plurality of concave grooves 21 a extending in the front-rear direction are formed in portions excluding the left and right ends in the drawing, and the second heat transfer block 22 On the upper surface side, a plurality of ridges 22a fitted into the respective concave grooves 21a are formed extending in the front-rear direction.
[0035]
The tip of this time, the corners of the front Stories tip of each groove 21a of the first heat transfer block 21 (inlet) (the edge of the corner), and the second respective projections 22a of the heat transfer block 22 The corners are cut diagonally (so-called chamfering is performed).
[0036]
As shown only on the left side, an inclined surface is formed on the left end portion of the first heat transfer block 21 from the lower surface to the left side surface, and thus an alignment portion 23 is provided. On the other hand, the left end portion of the second heat transfer block 22 is provided with a rising wall portion that rises upward and has an inner wall portion that is an inclined surface. An alignment unit 24 that performs alignment in the left-right direction between the heat transfer blocks 21 and 22 is provided. Moreover, the corner | angular part inside the upper end of the rising wall part of the 2nd heat-transfer block 22 is also notched diagonally. Note that a similar alignment portion is also formed symmetrically at the right end (not shown).
[0037]
In the above configuration, when the heat transfer blocks 21 and 22 are combined, since the corners of the tips of the concave groove 21a and the ridge 22a are cut obliquely, even if there is a slight misalignment between them, The chamfered portions are guided to each other in the fitting direction so that the positioning is automatically performed, so that the fitting between the groove 21a and the protrusion 22a is performed more smoothly, and the assembling property is improved. Can be increased.
[0038]
Furthermore, by providing the alignment portions 23 and 24 on the outer peripheral portions of the heat transfer blocks 21 and 22, the heat transfer blocks 21 and 22 can be roughly aligned at the time of assembling. Can be increased. Both In the example of this, and the notch District constituting the corner portion obliquely the tip of the concave grooves 21a and ridges 22a, a structure provided with positioning portions 23, 24 on the outer periphery of the heat transfer block 21 However, any one of them may be omitted.
[0039]
Figure 4 shows a first embodiment of the present invention. The figure shows the configuration of one heat transfer block 31, which is also formed in a rectangular block shape (plate shape) from aluminum or the like, and a plurality of concave grooves 31a on the upper surface side thereof. And the protruding item | line 31b is extended in the radial direction from the center part, and is formed by turns in the circumferential direction. Although not shown, the heat transfer block combined with the heat transfer block 31 is formed with concave grooves and ridges having a reverse concavo-convex relationship on the lower surface side, and is combined by a fitting structure. ing.
[0040]
In the said structure, since the thermal expansion coefficient differs between the heat-transfer blocks 31 combined by forming the concave groove 31a and the protruding item | line 31b of the heat-transfer block 31 extending radially, mutual expansion | swelling is carried out at the time of use. Even when the degrees are different, it is possible to absorb the difference in the degree of expansion by slipping between them, and stress is applied to the grooves 31a or the ridges 31b to deform the heat transfer block 31 and thus the electronic component 4. It is possible to prevent adverse effects on In other words, it is possible to use materials having different coefficients of thermal expansion between the heat transfer blocks 31 to be combined.
[0041]
Figure 5 shows a second embodiment of the present invention. The heat transfer block 41 in this embodiment should be referred to as a modification of the heat transfer block 31 of the first embodiment, and a plurality of concave grooves and ridges radiate from the center on the upper surface side. In this case, the number of the grooves and the protrusions on the outer peripheral side is larger than the inner peripheral side of the heat transfer block 41, and the number of the grooves changes. A ring-shaped groove is formed in the portion to be formed.
[0042]
Specifically, for example, at the center portion (innermost peripheral portion) of the heat transfer block 41, two concave grooves 41a and ridges 41b are provided, and the outer peripheral side thereof is provided with a ring-shaped groove 41c. Twelve concave grooves 41d and convex ridges 41e are provided, and 24 concave grooves 41g and convex ridges 41h are provided on the outer peripheral side thereof via ring-shaped grooves 41f. The ring-shaped grooves 41c and 41f are formed with a depth equivalent to the recessed grooves 41a, 41d and 41g. Although not shown in the figure, the heat transfer block combined with the heat transfer block 41 is formed with concave grooves, ridges, and ring grooves that have an opposite concave-convex relationship on the lower surface side.
[0043]
According to the said structure, even if the thermal expansion coefficient between the heat-transfer blocks 41 combined differs similarly to the said 1st Example, it becomes possible to absorb the difference in an expansion degree. And with this, the appropriate width (ratio of width to height) of the grooves 41a and 41d and the ridges 41b and 41e on the inner peripheral side of the heat transfer block 41 can be ensured, and the number of the change portions can be changed. By providing the ring-shaped grooves 41c and 41f, the protrusions can be made without interfering with each other.
[0044]
In addition, this invention is not limited to each above-mentioned Example, A various expansion and change are possible within the range which does not deviate from a summary. For example, the material of the heat transfer block is not limited to aluminum, and other metals, ceramics with good thermal conductivity, and the like can also be used. In this case, not only extrusion molding but also various methods can be used. Various deformations can be considered as the shape of the heat transfer block.
[0045]
It is also possible to combine the heat transfer blocks by shifting an integral number of grooves. This can be used to absorb a large positional shift at the time of combination. As for the heat radiating portion, the housing (outer wall) may not be a heat radiating portion, but a heat radiating portion having heat radiating fins may be provided separately.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view showing a basic configuration of an electronic device and showing a schematic configuration of the electronic device. FIG. 2 shows a modification example of a heat transfer block in which three heat transfer blocks are combined. Front view (a) and right side view (b)
FIG. 3 shows a different modification of the heat transfer block, and is a partial front view of a state in which the heat transfer blocks are combined. FIG. 4 shows the first embodiment of the present invention and shows one heat transfer block. Top view (a) and side view (b)
FIG. 5 is a view corresponding to FIG. 4 showing a second embodiment of the present invention.
In the drawings, 2 is a housing (heat radiation part), 4 is an electronic component, 5, 6, 11, 12, 13, 21, 22, 31, 41 are heat transfer blocks, 5a, 6a, 11a, 12a, 12c, 13a. , 21a, 31a, 41a, 41d, 41g are concave grooves, 5b, 6b, 11b, 12b, 12d, 13b, 22a, 31b, 41b, 41e, 41h are ridges, 23, 24 are alignment parts, 41c, 41f Indicates a ring-shaped groove.

Claims (2)

It is configured to transmit the heat of the electronic component to the heat radiating part through two or more heat transfer blocks having good thermal conductivity in order,
Between the heat transfer blocks, due to the fitting structure between the groove and the ridge, the wall surfaces of the groove and the ridge are in contact with each other to transmit heat ,
The heat dissipation structure for an electronic component, wherein the concave grooves and the ridges are provided to extend radially from a central portion of the heat transfer block . The concave grooves and the ridges are formed so that the number on the outer peripheral side is larger than the inner peripheral side of the heat transfer block, and a ring-shaped groove is formed in a portion where the number changes. radiating structure for an electronic component according to claim 1, wherein the that.

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