JP2007080989A - Heat sink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance heat sink which suppresses the rise of ventilating resistance (pressure loss) of a fin main body as a heat sink for a large heat capacity element to secure the sufficient flow rate of cooling air, and increase the heat dissipating function of the whole of heat sink as a result, thereby permitting the improvement of a cooling efficiency. <P>SOLUTION: Sub-fins 14a, 14b are formed between mutually neighbored main fins 13a, 13b so that the sub-fins 14a, 14b are formed so as to be shifted mutually to different positions in the direction of height H of the substrate 12. In this embodiment, the sub-fins 14a, 14b are arranged in so-called zigzag array, in which the sub-fins 14a, 14b are shifted respectively by the half width of respective forming pitch in the direction of height H, on the mutually neighbored main fins 13a, 13b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat sink, and more particularly to a heat sink for forcibly cooling a heat generating portion with a cooling fluid such as air flowing by a fan or the like.

  For example, in order to cool a large-capacity heating element, a method of cooling the element using a boiling cooler or a heat pipe has been generally used. FIG. 5 shows an external view of an example of a boiling cooler. The boiling cooler 100 has a pedestal 101 to which a heat generating element 104 is attached. A cooling tower 102 is connected to the pedestal 101, and a large number of fins 103 are installed on the outer peripheral surface of the cooling tower 102. .

  Further, the pedestal 101 and the cooling tower 102 are formed in an integral container, and a cooling medium 106 such as fluorocarbon which is easily vaporized and has a large heat of vaporization is enclosed therein. In this boiling cooler, the cooling medium 106 on the pedestal 101 at the lower part of the cooling tower 102 is vaporized by the heat generated by the element 104 and rises to the upper part of the cooling tower 102. The cooling medium that has risen to the upper part of the cooling tower 102 is condensed by the heat radiation of the fins 103 and then descends to the base 101 again. By repeating such circulation of the cooling medium, the amount of heat generated by the element is dissipated and the element is prevented from being heated to maintain a constant temperature.

  However, in recent years, boiling coolers and heat pipes that use refrigerants are being abolished due to environmental problems related to global warming, and there is a significant tendency to switch to dry high-performance heat sinks that do not use refrigerants. For example, a heat exchanger called a heat sink is installed in various heat generating parts of inverters, machine tools, etc., and a cooling fluid such as air is forced to flow through the heat sink by a fan or the like. Has been. The heat sink is made of a metal having good thermal conductivity, and is configured to suppress the temperature rise of various heating elements by increasing the surface area as much as possible to increase the contact area with the cooling medium.

Hereinafter, an example of a conventional heat sink of this type will be described.
6 to 8 are front views illustrating the configuration of a conventional heat sink. A conventional heat sink 111 shown in FIG. 6 includes a substantially rectangular planar substrate 112 on which electronic components (not shown) such as thyristors and transistors are fixed, and a number of corrugated plate bending layers stacked on the substrate 112. It is comprised from the fin 113 which has the fin body 113a. This heat sink is unsuitable for the purpose of dissipating a large amount of heat because the heat exchange efficiency of the plate bending fins is greatly reduced as the height increases.

  A conventional heat sink 121 shown in FIG. 7 includes a substantially rectangular planar substrate 122 on which electronic components (not shown) such as thyristors and transistors are fixed, and a lattice-shaped fin 123 made of an extrusion material attached on the substrate 122. It is configured. This heat sink has a minimum thickness of about 0.6 mm for the extruded material, so the pressure loss at the fins is large, and the cooling capacity is low because the required cooling fluid such as air cannot be obtained. It was difficult to increase the cooling efficiency.

  A conventional heat sink 131 shown in FIG. 8 includes a substantially rectangular planar substrate 132 on which electronic components (not shown) such as thyristors and transistors are fixed, and a large number of flat vertical plates standing on the substrate 132. It is comprised from the fin 133 which has the fin body 133a. The vertical fin bodies 133a are opposed to each other in a desired flow direction of the cooling fluid such as air (direction perpendicular to the paper surface in the drawing) with the side surfaces facing each other, and maintaining a proper gap G. Arranged in parallel.

These heat sinks are used for small and low-capacity elements with an element heat generation of 0.6 to 2 kW, and the air speed applied to the fins is 2 to 3 m / s and is cooled by using a sirocco fan or the like. Has been adopted.
JP-A-8-222665

  In recent years, the capacity of electronic devices has increased, and a device having a 3 kW type heat generation amount has been put into practical use, and electronic devices using a plurality of such large capacity devices have been adopted. In order to improve the performance of the heat sink in response to high heat generation elements, the fin surface area can be increased by increasing the surface area of the fins or reducing the spacing between the fins to increase the number of fins installed. A method of density arrangement is conceivable. Even with a structure in which fins are arranged at high density, there is a limit to increasing the number of fins. If the gap between the fins is narrowed, the airflow resistance (pressure loss) of cooling fluid such as air passing between the fins is limited. ) Increases, resulting in a problem that the amount of air passing through the fin body is reduced and the cooling efficiency cannot be improved.

  For example, heat sinks for control elements that generate a large amount of heat, such as modern vehicle control equipment, cannot be increased infinitely due to restrictions on the mounting location, and cooling can be achieved simply by devising the fin arrangement. It has been found that there is a limit to the improvement in performance and the required cooling performance cannot be satisfied.

  Therefore, a method of cooling with a large amount of cooling air by increasing the wind speed of the cooling air blown into the fins to 5 to 13 m / second has been attempted. However, when the wind speed is increased, the pressure loss rapidly increases in the lattice fins, and the problem arises that the air volume does not increase as expected.

  The object of the present invention is to suppress an increase in the ventilation resistance (pressure loss) of the fin body as a heat sink for a large heat capacity element, ensure a sufficient flow rate of cooling air, and as a result, improve the heat dissipation function of the entire heat sink, An object of the present invention is to provide a high-performance heat sink that can improve efficiency.

  In order to achieve the above object, according to the present invention, a substrate on which a heat source body is arranged on the back surface, a plurality of plate-like main fins rising in the height direction in parallel at a predetermined interval from the surface of the substrate, The main fins are extended from both side surfaces of the main fins toward the adjacent main fins, and the extension ends are spaced apart from the adjacent main fins and are intermittently formed in the height direction of the main fins. There is provided a heat sink comprising a plurality of sub-fins, wherein the sub-fins between the main fins adjacent to each other are formed at different positions in the height direction of the substrate. .

  The sub-fins between the main fins adjacent to each other need only be formed in a staggered arrangement with respect to each other in the height direction of the substrate. The main fins only need to be intermittently formed with rectifying fins extending so as to connect the adjacent main fins in the height direction of the substrate.

  The main fin may be formed with a thickness (T) in the range of 0.8 mm to 2.5 mm. The interval (P) between the main fins may be in the range of 3 mm to 10 mm. The sub-fins may be formed with a thickness (t) in the range of 0.4 mm to 1.2 mm. The sub fins may be formed so that the width (w) from the side surface of the main fin to the extended end is in the range of 20% to 50% of the interval (P) between the main fins.

  According to the heat sink of the present invention, since the sub fins are provided on the side surfaces of the main fins so as to be shifted from each other at least different positions in the height direction with respect to the adjacent main fins, the surface area where the cooling fluid and the heat sink contact each other. Therefore, it is possible to increase the efficiency of heat exchange as compared with a conventional heat sink. Thereby, even if it does not increase the thickness of the fin which comprises a heat sink, the formation pitch of fins can be raised and a heat sink with a sufficient cooling efficiency can be implement | achieved.

  In addition, since the sub fins adjacent to each other are arranged so as to be shifted from each other, the cooling fluid passing through the heat sink causes a moderate turbulent flow. By causing a turbulent flow in the cooling fluid, the cooling fluid is appropriately stirred in the heat sink, and it is possible to reduce the temperature unevenness of the cooling fluid and efficiently perform heat exchange.

  Then, by the rectifying fins extending so as to connect the main fins adjacent to each other, the space is completely separated at the upper and lower portions of the rectifying fins in the height direction of the substrate, and the cooling fluid has a height exceeding the rectifying fins. Suppressing in the direction H is suppressed. This prevents excessive turbulence from occurring in the height direction of the substrate that prevents the cooling fluid from smoothly passing along the depth direction while appropriately stirring the cooling fluid by the sub fins. .

  Hereinafter, the present invention will be described in detail with reference to the drawings. 1 and 2 show a heat sink of the present invention. FIG. 1 is an external perspective view thereof, and FIG. 2 is a sectional view of FIG. 1 when viewed from the front. Note that FIG. 1 shows only a part of FIG. 2, and the size ratio of each part does not necessarily reflect an actual dimension for easy understanding of the structure.

  As shown in FIGS. 1 and 2, the heat sink 11 of the present invention includes a square substrate 12 having a longitudinal dimension L and a lateral dimension W of about 600 mm, for example. For example, an electronic component (heat source body) 16 (not shown in FIG. 1) such as a thyristor or a transistor is mounted on the back surface 12b of the substrate 12. The shape of the substrate 12 is not limited to a square flat plate, and various shapes such as a planar rectangular shape, a planar elliptical shape, and a planar circular shape can be employed. As the material of the substrate 12, a metal having good thermal conductivity such as aluminum or copper is used. In particular, it is preferable to use aluminum or an aluminum alloy from the viewpoint of weight reduction.

  A plurality of main fins 13 a and 13 b are formed on the surface 12 a of the substrate 12 at a predetermined interval. The main fins 13a and 13b are formed of, for example, a metal plate having excellent thermal conductivity, and rise in parallel with each other in the height direction H perpendicular to the surface 12a of the substrate 12.

  Both side surfaces S extending along the height direction H of the main fins 13a and 13b extend toward the main fins 13a and 13b adjacent to each other (that is, extend in a horizontal direction perpendicular to the height direction H). ) A large number of plate-like sub fins 14a and 14b are formed. The sub fins 14a and 14b extend along the depth direction D of the heat sink 11, and the extended ends E of the sub fins 14a and 14b are formed so as to be spaced apart from the adjacent main fins 13a and 13b, respectively. In addition, the main fins 13a and 13b are intermittently formed at a predetermined pitch in the height direction H.

  The sub fins 14 a and 14 b are formed so that the sub fins 14 a and 14 b are shifted from each other in the height direction H of the substrate 12 between the main fins 13 a and 13 b adjacent to each other. That is, in this embodiment, the main fins 13a and the main fins 13b adjacent to each other are arranged in a so-called staggered arrangement in which the main fins 13a and the main fins 13b are shifted from each other by a half width of each formation pitch in the height direction H.

  Further, on both side surfaces S of the main fins 13a and 13b, rectifying fins 15 extending so as to connect the adjacent main fins 13a and 13b are intermittently formed in the height direction h of the substrate 12. Yes. The space is completely separated between the upper and lower portions of the rectifying fins 15 in the height direction H of the substrate 12.

  The main fins 13a and 13b, the sub fins 14a and 14b, and the rectifying fins 15 are preferably made of a metal having good thermal conductivity, such as aluminum or an aluminum alloy, and are integrally manufactured by extrusion molding of aluminum or an aluminum alloy. The And it brazes and fixes to the surface 12a of the board | substrate 12 using a brazing sheet.

  In the heat sink 11 having such a configuration, the flow direction of the cooling fluid is set along the depth direction D. For example, cold air is flowed as the cooling fluid along the depth direction D of the heat sink 11, thereby The heat generated from the heat source body such as the electronic component 16 disposed in 12b is cooled by heat exchange.

  FIG. 3 is a partially enlarged view of the heat sink 11 shown in FIG. The main fins 13a and 13b are formed with a thickness (T) in the range of 0.8 mm to 2.5 mm, for example. Further, the distance (P) between the main fins 13a and 13b may be in the range of 3 mm to 10 mm.

  On the other hand, the sub fins 14a and 14b may be formed with a thickness (t) in the range of 0.4 mm to 1.2 mm. Further, the sub fins 14a and 14b have a width (w) from both side surfaces S extending along the height direction H of the main fins 13a and 13b to the extension end E from 20% to 50% of the interval (P) between the main fins. %, For example, about 0.6 mm to 5 mm.

  Next, the operation of the heat sink of the present invention configured as described above will be described with reference to FIGS. The heat generated from the heat source body such as the electronic component 16 disposed on the back surface 12 b of the substrate 12 is propagated to the heat sink 11 through the substrate 12. Then, by flowing a cooling fluid, for example, cold air in the depth direction D of the heat sink 11 by a fan or the like, the heat of the heat sink 11 is transmitted to the cold air, the cold air is warmed and discharged, and the heat sink 11 is cooled. So-called heat exchange occurs. By this heat exchange, the heat source body such as the electronic component 16 disposed in contact with the heat sink 11 is cooled without the temperature continuously rising, and the occurrence of malfunction due to heat is prevented.

  Thus, when flowing the cooling fluid to the heat sink 11, the heat sink 11 of the present invention is arranged in a staggered arrangement with respect to the main fins 13a and 13b adjacent to each other on the side surfaces of the main fins 13a and 13b. Since the sub fins 14a and 14b are provided so as to be shifted from each other by a half width, it is possible to increase the surface area where the cooling fluid and the heat sink 11 are in contact with each other, and the heat exchange efficiency can be improved as compared with the conventional heat sink. It becomes possible. Thereby, even if it does not increase the thickness of the fin which comprises a heat sink, the formation pitch of fins can be raised and a heat sink with a sufficient cooling efficiency can be implement | achieved.

  In addition, since the sub fins 14a and 14b adjacent to each other are arranged in a staggered manner shifted by a half width, the cooling fluid passing through the heat sink 11 causes a moderate turbulent flow. By causing a turbulent flow in the cooling fluid, the cooling fluid is appropriately agitated in the heat sink 11, and it is possible to reduce the temperature unevenness of the cooling fluid and efficiently perform heat exchange.

  The space is completely separated between the upper and lower portions of the rectifying fins 15 in the height direction H of the substrate 12 by the rectifying fins 15 extending so as to connect the main fins 13a and 13b adjacent to each other. And the cooling fluid is prevented from moving up and down in the height direction H. Accordingly, the cooling fluid is moderately stirred by the sub fins 14a and 14b arranged in a staggered arrangement, but the cooling fluid is prevented from passing smoothly along the depth direction D in the height direction H of the substrate 12. Prevent excessive turbulence from occurring.

  The applicant has verified the effect of the heat sink of the present invention. In the verification, a suction type in which an axial fan is installed on the outflow side of the heat sink as shown in FIG. 4A, and an axial fan is installed in the inflow side of the heat sink as shown in FIG. 4B. In both indentation types, the heat sink of the present invention as shown in FIG. 1 is provided, a dummy heater (heat source body) having a calorific value of 1170 W is used, and an axial flow fan having a diameter of 100 mm pushes air in or out as a cooling medium. In both cases, the maximum temperature was measured by a thermocouple for temperature measurement.

  In addition, as a conventional comparative example, the combination shown in FIGS. 4A and 4B described above is used, and only the heat sink is formed in a lattice shape as shown in FIG. Was measured.

The results of such verification are shown below.
(Maximum temperature)
Example (Invention Example): Suction 64 ° C. Indentation 61.5 ° C.
Comparative example (conventional example): Suction 66 ° C Indentation 64 ° C

  From the verification results as described above, it was confirmed that the heat sink of the present invention was superior in cooling characteristics to a conventional heat sink having a lattice-like cross section in both pushing and sucking of the cooling medium.

It is an external appearance perspective view which shows an example of the heat sink of this invention. It is a top view which shows an example of the heat sink of this invention. FIG. 3 is a partially enlarged plan view of the heat sink of FIG. 2. It is explanatory drawing which shows the structure of the verification example of this invention. It is an external appearance perspective view which shows an example of the conventional heat sink. It is a top view which shows an example of the conventional heat sink. It is a top view which shows an example of the conventional heat sink. It is a top view which shows an example of the conventional heat sink. It is a top view which shows an example of the conventional heat sink.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Heat sink, 12 ... Board | substrate, 12 ... Control board, 13a, 13b ... Main fin, 14a, 14b ... Sub fin, 15 ... Rectification fin.

Claims (7)

  A substrate on which the heat source is arranged on the back surface, a plurality of plate-like main fins that rise in the height direction in parallel at a predetermined interval from the surface of the substrate, and adjacent main fins from both side surfaces of the main fins A plurality of sub-fins that are extended in the direction of the main fin and are intermittently formed in the height direction of the main fin, the extension ends of which are spaced apart from the adjacent main fin, and the main fins adjacent to each other The heat sink, wherein the sub-fins are formed so as to be shifted from each other at least different positions in the height direction of the substrate.   The heat sink according to claim 1, wherein the sub fins between the main fins adjacent to each other are formed in a staggered arrangement with each other in the height direction of the substrate.   The heat sink according to claim 1 or 2, wherein a rectifying fin extending so as to connect between adjacent main fins is intermittently formed in the main fin in the height direction of the substrate. .   The heat sink according to claim 1, wherein the main fin has a thickness (T) in a range of 0.8 mm to 2.5 mm.   The heat sink according to claim 1, wherein a distance (P) between the main fins is in a range of 3 mm to 10 mm.   The heat sink according to claim 1, wherein the sub fin has a thickness (t) in a range of 0.4 mm to 1.2 mm. The sub fin is formed such that a width (w) from a side surface to an extended end of the main fin is in a range of 20% to 50% of a distance (P) between the main fins. Item 2. The heat sink according to Item 1.

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