JP2008159757A - Cooling structure of heat generating substance, and manufacturing method of same cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure of a heat generating substance which is compact and exhibits a high cooling performance, and provide a method capable of advantageously manufacturing the cooling structure. <P>SOLUTION: In the cooling structure 2 of a heat generating substance, a plurality of inner tubes 6 having a small diameter are inserted into an outer tube 4 having a large diameter to closely contact them with each other; the outer peripheral surface of each inner tube 6 is brough into close contact with the inner peripheral surface of the outer tube 4 and/or the outer peripheral surface of each other inner tube 6 is brough into close contact with the inner peripheral surface of the outer tube 4. Further, at least one flat plane 8 for attaching thereto a heat generating substance 10 is disposed on the outer peripheral surface of the outer tube 4 and a cooling liquid is forced to flow through the inside of each inner tube 6 and the entire clearance between each inner tube 6 and the outer tube 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling structure for cooling a heating element such as an electric / electronic component and a method for advantageously manufacturing the same.

  Conventionally, various types of water-cooled (liquid-cooled) heat sinks and cooling devices with excellent cooling capabilities have been proposed as cooling structures for heating elements composed of electronic components, for example, In JP 2002-170915 A (Patent Document 1), the opening of a pan-shaped casing having a flat bottom is closed with a base plate to form a flat flow path inside, and in the flow path, A water-cooled heat sink having a structure in which a corrugated inner fin is arranged and a partition plate for a return pass is arranged so as to press the valley or top of the wave of the inner fin is disclosed. In 2005-123260 (patent document 2), as an improvement technique of the heat sink disclosed in the cited document 1, water constructed by inserting an inner fin into a flat tube so as to be in close contact with the heat sink is disclosed. It revealed the expression sink, where the as an inner fin, an offset fin made aimed at stirring effect of the cooling water aluminum is also disclosed.

  Furthermore, in Japanese Patent Laid-Open No. 2006-202800 (Patent Document 3), as one of conventional devices related to a cooling device for a semiconductor element, a cooling structure comprising a so-called flat multi-hole tube formed by extrusion. However, in the invention of Patent Document 3, in order to improve the cooling performance by causing disturbance in the flow of the refrigerant and promoting it, such flattened It has been proposed that the partition wall of the hole tube has a structure in which irregularities are provided or the partition wall is cut and raised.

  By the way, in this kind of cooling device, it is generally desired to make it as compact as possible because space is limited during installation, and the amount of heat generated from the heating element is increasing more and more. Therefore, there is a need for further higher cooling performance. However, in the cooling structure of a heating element that has been proposed so far, such compactness and higher cooling performance are achieved. It is not possible to fully respond to this request, and various problems are inherent.

  For example, in a water-cooled heat sink having a configuration disclosed in Patent Document 1, brazing is performed by combining a pan-shaped casing and a base plate in order to form a flow path space. Therefore, inevitably, in addition to the problem of reliability of the sealing performance of the joint between these parts, in Patent Document 1 and Patent Document 2, corrugated inner fins are arranged in the internal space. Since it is supposed to be fixed by brazing or the like, the adhesion between the inner fin and the casing is not sufficient, and there is a limit in improving the heat transfer characteristics between them. As in Patent Document 3, when unevenness is provided on the partition wall of a flat multi-hole tube or when the partition wall is cut and raised, the operation is not easy, which reduces the product cost. It has also become factors that allowed to rise.

  Under such circumstances, the cooling structure composed of a flat multi-hole tube, which is clarified as the prior art in FIG. 5 of Patent Document 3, is a relatively simple structure and has no joint part such as brazing. From the point of view of the product, it is preferable from the viewpoint of the reliability of the seal. However, there is a problem that the cooling performance is limited when the cooler is made compact. That is, in order to make the cooler compact, it is necessary to secure a sufficiently large coolant flow path in a limited cross section and also sufficiently secure the heat transfer surface of the coolant and the tube. However, it is not possible to fully meet such demands. By the way, in the cooler using a flat multi-hole tube, the inner wall of the tube is made as thin (thin) as possible, and the cooling performance is improved by increasing the number, but in the extrusion process, It is not easy to form many thin inner walls in a small cross-sectional shape of a hollow tube.

  Moreover, when the tube material is aluminum or aluminum alloy with good extrudability, the hollow material can be extruded by porthole extrusion, but the small cross section and the complicated cross section as described above. Extrusion of the shape becomes extremely difficult, and when using copper or copper alloy with good thermal conductivity as the tube material, the hollow tube as described above is formed by extrusion It was almost impossible to do.

JP 2002-170915 A JP-A-2005-123260 JP 2006-202800 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to provide a cooling structure for a heating element that is compact and exhibits high cooling performance. Another object is to provide a method capable of advantageously producing a cooling structure for a heating element having such excellent performance.

  In the present invention, in order to solve such a problem, a heating element having a structure in which a plurality of thin inner pipes are inserted into a thick outer pipe and closely arranged. In the cooling structure, the outer peripheral surface of the inner tube is in close contact with the inner peripheral surface of the outer tube and / or the outer peripheral surface of the inner tube in close contact with the inner peripheral surface of the outer tube, and An outer peripheral surface of the outer tube is provided with at least one flat surface to which the heating element is attached, and the coolant is allowed to flow through the inner tube and the entire gap between the inner tube and the outer tube. The gist of the cooling structure for the heating element, characterized in that it is configured as described above.

  According to a desirable aspect of the cooling structure for a heating element according to the present invention, the outer tube and the inner tube are each composed of copper or a copper alloy, and according to another desirable aspect, The inner tube is formed of a thin tube body than the outer tube.

  In order to manufacture such a cooling structure for a heating element according to the present invention, in the present invention, after inserting the plurality of inner tubes into the outer tube, the outer surface of the outer wall of the outer tube The outer tube is compressed and deformed by applying an external force to the inner tube so that the outer surface of the inner tube is in close contact with the inner surface of the outer tube and / or the inner surface of the outer tube. A method of manufacturing a cooling structure for a heating element, which includes a step of bringing the surface into close contact with the surface, is preferably employed.

  Therefore, in the cooling structure for a heating element according to the present invention as described above, a predetermined heating element is attached to a flat surface provided on the outer peripheral surface of the outer pipe, while the outer pipe and the outer pipe and the inner pipe are attached. In the outer pipe to which the heating element is attached, the inner pipe is in close contact with the inner pipe so that the cooling liquid is circulated through the entire gap between them. The heat spreads to the entire tube wall of the outer tube by heat conduction, and heat is transferred from the tube wall of the outer tube to the tube wall of the inner tube. As a result, not only the inner surface of the outer tube, The inner and outer surfaces of the inner pipe also serve as heat transfer surfaces to the coolant, so the heat transfer area to the coolant can be effectively increased and high cooling capacity can be demonstrated. It becomes.

  Moreover, such a cooling structure for a heating element according to the present invention has an integrated structure in which a plurality of thin inner pipes are inserted into a thick outer pipe and closely arranged. In addition, since it is not necessary to have a brazed joint or an O-ring mounting portion, the compactness can be advantageously realized. Also, in terms of structure, a small diameter is provided within a large diameter outer tube. Since it is constructed by inserting a plurality of inner pipes, it is possible to form a large number of inner walls to be heat transfer surfaces in a small cross-sectional shape without adopting a special operation such as extrusion. Easy to do.

  In particular, according to the method for manufacturing a cooling structure for a heating element according to the present invention, after inserting a plurality of inner tubes into the outer tube, an external force is applied to the outer wall surface of the outer tube to compress and deform the outer tube. Therefore, a structure in which the outer tube and the inner tube are brought into close contact with each other can be easily realized, so that no work such as brazing is required, and only simple compression deformation is required. The characteristic feature is that the tube constituting the target cooling structure can be easily formed.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows an embodiment of a cooling structure for a heating element according to the present invention in a cross-sectional view that is a cross section perpendicular to the axis. The cooling structure 2 includes an outer tube 4 having a large diameter and a thick rectangular flat shape, and three inner tubes 6 which are housed in the outer tube 4 and have a small diameter and a thin elliptical shape. These three inner pipes 6 are inserted and arranged with their outer peripheral surfaces in close contact with each other and with the inner peripheral surface of the outer pipe 4. Moreover, the upper and lower outer peripheral surfaces of the outer tube 4 having a flat and substantially rectangular shape are flat surfaces 8 and 8, respectively, which are heating element mounting surfaces. All of the inside of the inner tube 6 (inside the tube) and the gap between the inner tube 6 and the outer tube 4 serve as a coolant flow path.

  And, as shown in FIG. 2 (a) or (b), the cooling structure 2 has, on one of the upper and lower flat surfaces 8, 8 provided on the outer peripheral surface of the outer tube 4, Alternatively, the heating element 10 to be cooled is attached to both of them and used.

  Therefore, in the cooling structure 2 having such a configuration, a plurality of (here, three) inner tubes 6 are in close contact with the inner peripheral surface of the outer tube 4 to which the heating element 10 is attached. However, since the cooling liquid introduced from the end portion is circulated in the gap between the inner pipe 6 and the outer pipe 4 together with the inside of the inner pipe 6 from the place where the insertion is arranged. Thereby, the heat of the high heat density of the heating element 10 attached to the flat surface 8 of the outer tube 4 spreads to the entire tube wall of the outer tube 4 by heat conduction, and from the tube wall of the outer tube 4 to the inner tube. Therefore, heat is transferred to the 6 tube walls. For this reason, not only the inner surface of the outer tube 4 but also the inner and outer surfaces of the inner tube 6 become heat transfer surfaces to the cooling liquid, and thus the heat transfer area to the cooling liquid. Can be effectively increased, and a high cooling capacity can be exhibited.

  The outer tube 4 and the inner tube 6 that also function as a heat transfer body of heat from the heating element 10 constituting the cooling structure 2 are here made of copper or copper alloy having good thermal conductivity. As a result, the cooling capacity of the cooling structure 2 is further improved.

  Thus, in the heating element cooling structure 2 according to the present invention, in order to transfer the heat of the heating element 10 from the outer tube 4 to the inner tube 6, the inner peripheral surface of the outer tube 4 and the inner tube 6. The outer peripheral surface of the inner tube 6 and the outer peripheral surface of the inner tube 6 that is in close contact with the inner peripheral surface of the outer tube 4 need to be in thermal contact with each other in order to easily obtain such thermal contact. In this case, after the inner tube 6 is inserted into the outer tube 4, a process of compressing and deforming the outer tube 4 by applying an external force to the outer wall surface of the outer tube 4 is advantageously employed. . By adopting such a process, the desired cooling structure 2 is manufactured, so that a work such as brazing is not required, and a tube constituting the cooling structure 2 is formed only by simple compression deformation. Because you can. In this case, the means for applying an external force to the outer tube 4 and compressing and deforming it is not particularly limited. For example, a known means such as drawing or pressing with a diameter reducing die is appropriately employed. It is possible. Further, due to the compression deformation of the outer tube 4, the inner tube 6 is also deformed, and as shown in FIGS. 1 and 2, the inner tube 6 is deformed into an elliptical shape, and the inner tube 6 and the outer tube are deformed. The closeness between the four can also be advantageously increased.

  Here, as the outer tube 4 for providing the cooling structure 2, it is possible to use a tube in which at least one flat outer peripheral surface (8) is formed in advance, or a tube formed in a flat shape. However, by using a tube having a simple circular cross-sectional shape and applying an external force to the outer wall surface as described above, the flat surface 8 may be formed on the outer surface simultaneously with the inner tube 6. Is possible. Further, as the inner tube 6, it is advantageous in terms of cost if a tube having a simple circular cross section is used. Even in the case where a tube having a simple circular cross section is used as the inner tube 6, in the manufacturing method as described above, an external force is applied to the outer wall surface of the outer tube 4 to compress and deform it, as shown in FIG. Thus, it becomes an elliptical shape.

  Further, as described above, when an external force is applied to the outer wall surface of the outer tube 4 to compress and deform it, the inner tube 6 is connected to the outer tube 4 from the outer tube 4 in order to improve the adhesion between the outer tube 4 and the inner tube 6. The inner tube 6 used for this purpose is preferably a thin-walled tube whose wall thickness is thinner than that of the outer tube 4, as shown in FIG. Thus, the adhesion between the outer tube 4 and the inner tube 6 in the obtained cooling structure 2 is improved.

  It should be noted that the structure of the cooling structure 2 shown in FIG. 1 is only one of the typical embodiments of the present invention, and is merely an example, and the present invention is not limited to such implementation. It should be understood that the present invention is not construed as being limited in any way by the specific description of the form.

  For example, the number of the inner pipes 6 that are inserted into the outer pipe 4 and closely arranged is not limited to the three illustrated, but depends on the thickness of the outer pipe 4 and the inner pipe 6 that are used. An appropriate number is selected, and even in the arrangement form, not only one line but also a multi-stage arrangement form can be adopted as appropriate. In the embodiment shown in FIG. 3, the 13 inner pipes 6 are closely arranged in the outer pipe 4 in a form in which the inner pipes 6 are alternately stacked in two upper and lower stages. Here, each inner tube 6 has a structure in which the inner tube 6 is in close contact with the inner peripheral surface of the outer tube 4.

  FIG. 4 shows an example in which seven inner pipes 6 are inserted in two stages in the outer pipe 4 and are arranged closely, in which the heating element 10 on the outer peripheral surface of the outer pipe 4 is disposed. The flat surface 8 to be attached is provided only at one place, and the other surfaces are curved. In this case as well, six of the seven inner pipes 6 are all in direct contact with the inner peripheral surface of the outer pipe 4, and one of the inner pipes 6 at the lower center is adjacent to the inner pipe 6. 6 is brought into close contact with the inner peripheral surface of the outer tube 4.

  Further, in the example shown in FIG. 5, twelve inner pipes 6 are stacked in three stages and are closely arranged in the outer pipe 4 having a rectangular cross-sectional shape. In the form, the two inner pipes 6 on the inner side of the second stage are not directly in contact with the inner peripheral surface of the outer pipe 4 but from the heating element 10 via the inner pipe 6 in contact with the outer pipe 4. Heat transfer is performed.

  In addition, even in the arrangement form of the inner tube 6 in the cooling structure 2, as shown in FIG. 6A, the inner tube 6 is a single tube body that is continuous in the axial direction (coolant flow direction). 6B, as shown in FIG. 6B, the inner tube 6 is divided in the middle of the outer tube 4 in the axial direction, and the divided inner tube 6 is separated by a predetermined distance in the axial direction. A configuration in which they are arranged apart from each other is also advantageously employed. Thus, when the inner pipes 6 are arranged in the form divided in the middle, the cooling liquid becomes turbulent flow in the divided part, a stirring effect is produced, and heat transfer is promoted. The present invention is advantageously employed. Further, as shown in FIG. 6 (c), such a divided portion is one in which inner pipes 6 and 6 in a form divided in the tube axis direction are connected at a part thereof (connecting portion 7). However, in addition to being able to exert the same effect, the distance between the separated inner pipes 6 and 6 can be fixed and maintained. It is also a form.

  In addition, although not enumerated one by one, the present invention can be carried out in an embodiment to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the invention.

  Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. It goes without saying.

Example 1
As shown in FIG. 1, a cooling structure 2 having a structure in which three inner pipes 6 are inserted and arranged in an outer pipe 4 was manufactured. That is, after inserting the three inner tubes 6 into the outer tube 4 using the outer tube 4 having a thickness of 2 mm and the inner tube 6 having a thickness of 1 mm, each made of phosphorous deoxidized copper. 1 and formed into a rectangular flat shape as shown in FIG. 1, the outer tube 4 and the inner tube 6 were brought into close contact with each other, and the flat surface 8 on which the heat source (heating element 10) was installed was formed at the same time. . Note that the outer tube 4 formed in a rectangular flat shape has a width in the left-right direction in FIG. 1 of 50 mm and a thickness in the up-down direction of 15 mm.

The coolant flow path cross-sectional area in the cross section of the cooling structure 2 thus obtained is about 390 mm ² , and the cross-sectional space occupied by the cooling structure 2 is 50% or more with respect to 750 mm ² (50 mm × 15 mm). Secured in proportion. The area of the heat transfer surfaces, the length of the cooling structure 2: a 100mm per about ^{33000mm 2 (330mm 2 / mm)} . As a result, a compact and good cooling performance can be obtained.

-Comparative Example 1-
For comparison with the cooling structure 2 of the first embodiment, an extruded tube 20 having a three-hole structure as shown in FIG. 8 (a) in the same cross-sectional area (50 mm × 15 mm; the same cross-sectional space is occupied) is made of aluminum. It was formed by extrusion of an alloy, and a structure in which three flow paths 24 extending in parallel to each other were provided by two inner walls 22 having a wall thickness of 2 mm. In addition, since such an extruded tube 20 cannot be extruded with copper or a copper alloy, it is manufactured here using an aluminum alloy.

The thus obtained extruded tube 20 shown in FIG. 8A has a cross-sectional area of the coolant flow path of about 450 mm ² , and 750 mm ² (50 mm × 15 mm) with respect to the cross-sectional space occupied by the cooler. About 60%. Then, the area of the heat transfer surface is cooler Length: a 100mm per about ^{15000mm 2 (150mm 2 / mm)} .

  Therefore, the extruded tube 20 of Comparative Example 1 has a larger flow path cross-sectional area than the cooling structure 2 of Example 1, but the area of the heat transfer surface is significantly reduced. It is recognized that it is difficult to transfer heat sufficiently and the cooling performance is poor.

-Comparative Example 2-
A 7-hole aluminum alloy extruded tube 26 having a cross-sectional area similar to that of the extruded tube 20 of Comparative Example 1 as shown in FIG. 8B was obtained by extrusion. The wall thickness of the six inner walls 30 partitioning the seven flow paths 28 was 1.7 mm.

The cross-sectional area of the coolant flow path in the cross section of the obtained extruded tube 26 is about 390 mm ^2, which is equivalent to the cooling structure 2 of Example 1, but the area of the heat transfer surface is the length of the cooler: a 100mm per ^{22000mm 2 (220mm 2 / mm)} , becomes approximately 2/3 of the cooling structure 2 of example 1, it is found to be that the cooling capacity is poor.

-Example 2-
A cooling structure 2 having the cross-sectional shape shown in FIG. 4 and having 13 inner tubes 6 inserted and arranged in two stages in the outer tube 4 was produced in the same manner as in Example 1. The outer tube 4 and the inner tube 6 were made of phosphorous deoxidized copper. The outer tube had a thickness of 2 mm and the inner tube had a thickness of 0.8 mm.

The coolant flow passage cross-sectional area in the cross section of the cooling structure 2 thus obtained is about 320 mm ² , and is secured at a ratio of 40% or more with respect to the cross-sectional space occupied by the cooler: 750 mm ² (50 mm × 15 mm). Has been. Further, the heat transfer surface area is cooler Length: a per 100mm about ^{56000mm 2 (560mm 2 / mm)} , as compared to the cooler of the first embodiment, although the flow path cross-sectional area is reduced, heat transfer surfaces It was revealed that the cooling area was about 1.5 times larger.

It is sectional explanatory drawing which shows an example of the cooling structure of the heat generating body according to this invention. It is sectional explanatory drawing which shows the example of attachment of the heat generating body with respect to the cooling structure of the heat generating body shown by FIG. 1, (a) is the example which attached one heat generating body, (b) attached two heat generating bodies. Each example is shown. It is sectional explanatory drawing which shows the example from which the cooling structure of the heat generating body according to this invention differs. It is sectional explanatory drawing which shows the further different example of the cooling structure of the heat generating body according to this invention. It is sectional explanatory drawing which shows another example of the cooling structure of the heat generating body according to this invention. It is a perspective explanatory view which shows the example of different arrangement | positioning of the inner pipe | tube in the cooling structure of the heat generating body shown by FIG. 1, (a) shows the example which arranged the continuous one inner pipe | tube, (b) FIG. 2 shows an example in which inner pipes divided in the tube axis direction are arranged, and FIG. 1C shows a state in which an intermediate portion of one inner pipe is divided and a part of the inner pipes is connected. It is a perspective explanatory view about an inner pipe. It is sectional explanatory drawing which shows the example from which the extrusion tube which gives the conventional integrated cooling structure used in the comparative examples 1 and 2 differs, Comprising: (a) is the thing of the 3 hole type, (b) is the 7 Each hole type is shown.

Explanation of symbols

2 Cooling structure 4 Outer pipe 6 Inner pipe 7 Connecting part 8 Flat surface 10 Heating element 12 Header

Claims (4)

  A cooling structure of a heating element having a structure in which a plurality of thin inner pipes are inserted into a thick outer pipe and arranged closely, and the outer peripheral surface of the inner pipe is the inner pipe of the outer pipe. At least one flat surface that is in close contact with the peripheral surface and / or the outer peripheral surface of the inner tube that is in close contact with the inner peripheral surface of the outer tube, and to which the heating element is attached to the outer peripheral surface of the outer tube And a cooling structure for a heating element, characterized in that a cooling liquid is circulated in the inner pipe and the entire gap between the inner pipe and the outer pipe.   The cooling structure for a heating element according to claim 1, wherein each of the outer tube and the inner tube is made of copper or a copper alloy.   The cooling structure for a heating element according to claim 1 or 2, wherein the inner tube is configured by a tube body that is thinner than the outer tube. A method for manufacturing a cooling structure for a heating element according to any one of claims 1 to 3,
After the plurality of inner pipes are inserted into the outer pipe, an outer force is applied to the outer wall surface of the outer pipe to compress and deform the outer pipe, so that the outer peripheral surface of the inner pipe becomes the outer pipe. A method of manufacturing a cooling structure for a heating element, comprising the step of being brought into close contact with an inner peripheral surface of a tube and / or an outer peripheral surface of an inner tube in close contact with the inner peripheral surface of the outer tube .

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