JP2014203534A - Heat sink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sink with high heat radiation.SOLUTION: A heat sink 1 includes a heat sink base 11 to which heat generated in a heat generating source is transferred, and a plurality of radiation fins 12 which are provided in the heat sink base 11, in which irregularities are repeated in wave shapes in a vertical direction in the usage state of the heat generating source and which are arranged away from one another.

Description

  The present invention relates to a heat sink for dissipating heat generated by a heat generation source.

  As a heat generation source, for example, there is a light emitting diode (LED) element. In the LED element, when the element temperature rises, the resistance value decreases and the current flowing through the element increases, resulting in a change in luminance, a change in color tone, and the like. In addition, an increase in current causes a further increase in the element temperature and causes the LED element to deteriorate.

  Therefore, in an illuminating device using an LED element as a light source, it is important to appropriately design heat dissipation and suppress a temperature rise of the LED element.

  Patent Document 1 discloses a technique for radiating heat generated by an LED element with a heat sink in an automotive headlamp using the LED element as a light source.

JP 2005-166588 A

  However, even when a heat sink is used, in a situation where sufficient wind does not hit the heat sink including no wind, air having a high temperature due to heat transfer from the heat sink stays around the heat sink and the heat dissipation of the heat sink decreases.

  For example, in the case of an automotive headlamp as disclosed in Patent Document 1, the outside air introduced into the engine room by airflow from a running wind or an electric fan is led exclusively to an engine radiator, an air conditioner condenser, etc. Since it is not led to the heat sink of the automotive headlamp, this is likely to occur.

  This invention is made | formed in view of such a technical subject, and it aims at providing the heat sink with high heat dissipation.

  According to an aspect of the present invention, there is a heat sink thermally connected to a heat generation source, the heat sink base to which heat generated by the heat generation source is transmitted, and the unevenness provided on the heat sink base. There is provided a heat sink comprising a plurality of heat dissipating fins having a waveform repeated in the vertical direction in a use state of the heat generation source and arranged apart from each other.

  According to the above aspect, air having a low temperature continuously flows into the heat sink from the lower side of the gap due to upward natural convection generated in the gap between the fins, and the gap between the fins while the air meanders. Since it is suppressed that a temperature boundary layer develops on the surface of a radiation fin by flowing through, high heat dissipation can be realized.

It is the whole illuminating device perspective view which has a heat sink concerning the embodiment of the present invention. It is A arrow directional view of FIG. It is III-III sectional drawing of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is an overall perspective view of a lighting device 2 as a heat generation source having a heat sink 1 according to an embodiment of the present invention. In the drawing, the z-axis direction corresponds to the vertical direction in the usage state of the illumination device 2.

  The illuminating device 2 includes a light emitting diode (LED) element 3, a metal (for example, aluminum alloy) pedestal portion 4 on which the LED element 3 is mounted, and a metal (for example, an end portion of the pedestal portion 4). And an aluminum alloy) heat sink 1. In addition, when the illuminating device 2 is an automotive headlamp, it includes a reflector, a projection lens, a lamp cover, etc. (not shown).

  The LED element 3 has a light emitting chip 3a as a center, and is connected to a driving circuit (not shown) by wiring (not shown).

  The heat sink 1 includes a disk-shaped heat sink base 11 and a plurality of radiating fins 12 provided on the heat sink base 11.

  The radiating fin 12 is provided so that the unevenness is repeated in the vertical direction (z-axis direction in the figure), and the unevenness is concave or convex in the left-right direction (x-axis direction in the figure) parallel to the surface of the heat sink base 11. Corrugated fin.

  A plurality of the radiating fins 12 are arranged at intervals in the left-right direction so that the adjacent radiating fins 12 are parallel to each other, and a narrow and narrow gap 13 having a constant width is formed between the adjacent radiating fins 12. . Since the radiating fins 12 are corrugated, the gaps 13 meander left and right as shown in FIG.

  Further, as shown in FIG. 3, the heat dissipating fins 12 are thinner on the tip side than on the heat sink base 11 side. This is in order to improve releasability when the heat sink 1 is integrally formed by die casting or the like.

  In the present embodiment, in consideration of the heat transfer efficiency from the pedestal portion 4 to the heat sink 1, the heat sink 1 and the pedestal portion 4 are integrally formed by die casting.

  Then, the effect by employ | adopting the heat sink 1 of the said structure is demonstrated.

  The heat generated in the LED element 3 is transmitted to the heat radiating fins 12 through the pedestal 4 and the heat sink base 11. The heat transmitted to the radiation fins 12 is transmitted to the air around the radiation fins 12.

  As a result, the temperature of the air around the radiating fins 12 increases in temperature, the density thereof decreases, and the gap 13 between the adjacent radiating fins 12 increases. That is, upward natural convection occurs in the gap 13. As a result, the air whose temperature has increased due to heat exchange with the radiation fins 12 flows upward through the gap 13 and is discharged from above the gap 13. Then, air having a low temperature flows into the gap from below the gap 13.

  Moreover, since the radiation fin 12 has a waveform, the air rises through the gap 13 while meandering. Thereby, the air on the surface of the radiation fin 12 is disturbed and a temperature boundary layer is prevented from developing on the surface of the radiation fin 12, and heat radiation from the radiation fin 12 to the air flowing through the gap 13 can be promoted.

  Therefore, according to the heat sink 1 having the above structure, air having a low temperature continuously flows into the heat sink 1 by natural convection even in a situation where sufficient heat is not applied to the heat sink 1 including no wind. The development of the temperature boundary layer on the surface of the fin 12 is suppressed, and high heat dissipation can be realized.

  As a result, a rise in temperature of the LED element 3 and an increase in current caused thereby can be suppressed, the brightness and color tone of the LED element 3 can be stabilized, deterioration of the LED element 3 can be suppressed, and the life of the LED element 3 can be extended. .

  The embodiment of the present invention has been described above, but the above embodiment is merely a part of an application example of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

  For example, although the heat generation source has been described as the lighting device 2 in the above embodiment, the heat generation source may be a motor, a battery, an electronic component, a heat exchanger, or the like.

  Further, considering the heat transfer efficiency from the pedestal 4 to the heat sink base 11 and the heat transfer efficiency from the heat sink base 11 to the radiating fins 12, it is preferable to integrally form them as in the above embodiment, but these are separately formed. The structure may be formed and mechanically connected. If necessary, heat transfer grease and a heat transfer sheet are arranged in the connecting portion to suppress a decrease in heat transfer efficiency.

  In addition, the heat sink 1 and the pedestal portion 4 that are separately formed may be arranged apart from each other. In this case, a heat transfer member such as a heat pipe or a metal plate is disposed between the two and the heat sink 1 from the pedestal portion 4. Heat is transferred to 1.

  In addition, the radiating fins 12 are provided so that the unevenness is concave or convex in the left-right direction, but if a core material is erected on the heat sink base 11 and the radiating fins 12 are fixed to the core material, It is also possible to provide the unevenness so as to be concave or convex in a direction perpendicular to the surface of the heat sink base 11 (y-axis direction in the drawing) or in other directions. However, the heat dissipation is excellent in the configuration of the above embodiment in which heat is directly transferred from the heat sink base 11 to the heat radiating fins 12.

1 heat sink 2 lighting device (heat generation source)
3 Light emitting diode (LED) element 4 Base part 11 Heat sink base 12 Heat radiation fin

Claims (5)

A heat sink thermally connected to a heat generating source,
A heat sink base to which heat generated by the heat generation source is transmitted;
A plurality of heat dissipating fins provided on the heat sink base, wherein the irregularities have a waveform that is repeated in the vertical direction in the use state of the heat generation source, and are spaced apart from each other;
A heat sink characterized by comprising: The heat sink according to claim 1,
The plurality of heat radiation fins are provided on the heat sink base in a direction in which the unevenness is concave or convex in the left-right direction parallel to the surface of the heat sink base.
A heat sink characterized by that. The heat sink according to claim 1 or 2,
The plurality of radiating fins are arranged so that adjacent radiating fins are parallel to each other,
A heat sink characterized by that. A heat sink according to any one of claims 1 to 3,
The heat sink base and the plurality of heat radiating fins are integrally formed.
A heat sink characterized by that.   The heat sink according to any one of claims 1 to 4, wherein the heat generation source is integrally formed with a pedestal portion on which the heat generation source is mounted.

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