JP2017021912A - Heat sink and lighting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of obtaining satisfactory heat radiation efficiency in a heat sink having a to-be-cooled object disposed at a center thereof.SOLUTION: This heat sink 20 comprises: a plate substrate part 21 having a to-be-cooled object disposed at a center of a lower surface thereof; a columnar strut part 22 rising from the substrate 21 upward; and a heat radiation part 23 having plate-like fins. The heat radiation part 23 includes inner fins 31 extending radially about the strut part 22; intermediate fins 32 bifurcated from outer ends of the inner fins 31 and extending radially outward; outer fins 33 extending from outer ends of the intermediate fins 32 radially outward; and auxiliary fins 34 disposed between the outer fins 33 adjacent circumferentially. The intermediate fins 32 each include an intermediate bent part bent to one circumferential side as being closer to a radially outward side. A maximum curvature of the intermediate bent part is larger than maximum curvatures of the outer fins 33 and the auxiliary fins 34.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat sink and an illumination device using the heat sink.

  2. Description of the Related Art Conventionally, in a lighting device using a light source that generates a large amount of heat, a method of suppressing an excessive temperature rise of the lighting device by arranging a heat sink on the back surface of a light source that is a heat source is known. In recent years, LEDs (light-emitting diodes) have become widespread as light sources with high luminous efficiency and low heat generation. However, high-power LED modules with power consumption exceeding several tens of watts have a large amount of heat generation and need to be cooled. .

  2. Description of the Related Art Conventionally, as a heat sink that arranges an object to be cooled in the center, a heat sink provided with a plurality of fins extending radially outward from the vicinity of the object to be cooled is known. A conventional heat sink is disclosed in Patent Document 1, for example.

JP 2008-91644 A

  In the heat sink described in Patent Document 1, the heat dissipating area is increased by arranging fins densely (FIG. 1). In this heat sink, although the distance between the fins is narrow, efficient heat radiation is possible by aggressive ventilation by a fan used with the heat sink. However, there are cases in which a fan cannot be used together with a heat sink because of demands for low power consumption and cost reduction. When there is no positive air blowing by the fan, the flow of gas between the fins is suppressed, and there is a possibility that the heat radiation efficiency is lowered.

  This invention is made | formed in view of such a situation, and it aims at providing the technique in which favorable heat dissipation efficiency is obtained in the heat sink which arrange | positions a to-be-cooled object in the center.

  In order to solve the above-mentioned problem, the first invention of the present application is a plate-like substrate portion in which an object to be cooled is arranged at the center of the lower surface, a columnar column portion standing upward from the upper surface of the substrate portion, and the substrate. A plurality of plate-like fins erected upward from the portion, and the plurality of fins extend radially outward from the center of the support column and are substantially equal in the circumferential direction. A plurality of inner fins arranged at intervals, a plurality of intermediate fins bifurcated from the radially outer end of the inner fin and extending radially outward, and extending radially outward from the radially outer end of the intermediate fin A plurality of outer fins arranged at substantially equal intervals in the circumferential direction, and a plurality of auxiliary fins arranged in a substantially circumferential center of the outer fins adjacent in the circumferential direction and extending in the radial direction, Is the circumferential direction as it goes radially outward A plurality of the intermediate curved portions are arranged at substantially equal intervals in the circumferential direction, and the maximum curvature of the intermediate curved portions is the maximum curvature of the outer fin and the auxiliary fin. Larger than the heat sink.

  2nd invention of this application is a heat sink of 1st invention, Comprising: The said outer side fin and the said auxiliary | assistant fin curve to the one direction of the circumferential direction one side and the circumferential direction other side and the same direction as going to radial direction outer side. An outer curved portion.

  3rd invention of this application is a heat sink of 1st invention or 2nd invention, Comprising: The radial direction outer end of the said support | pillar part and each radial direction inner end of the said inner side fin are formed in a line, The said inner side fin The respective radial outer ends of the two and the radial inner ends of the two intermediate fins branched from the inner fin are formed in a continuous manner.

  4th invention of this application is a heat sink in any one of 1st invention thru | or 3rd invention, Comprising: The ratio for which the said intermediate fin occupies radial direction with respect to the diameter of the said thermal radiation part is 30% or more and 40% or less is there.

  5th invention of this application is a heat sink in any one of 1st invention thru | or 4th invention, Comprising: The ratio for which the said outside fin occupies the radial direction with respect to the diameter of the said thermal radiation part is 35% or more and 45% or less is there.

  A sixth invention of the present application is the heat sink according to any one of the first to fifth inventions, wherein a straight line connecting the center of the support column and the inner end of the intermediate curved portion, the center of the support column, and the intermediate The angle formed by the straight line connecting the outer end of the curved portion is 15 ° or more and 40 ° or less.

  A seventh invention of the present application is the heat sink according to any one of the first to sixth inventions, wherein the support column has a recess recessed downward from the upper surface.

  An eighth invention of the present application is the heat sink according to any one of the first to seventh inventions, wherein the number of the inner fins is twelve, the number of the intermediate fins, the number of the outer fins, and the auxiliary fins The numbers are all 24.

  A ninth invention of the present application is the heat sink according to any one of the first to eighth inventions, wherein an interval between the curved portions of the adjacent intermediate fins, and an interval between the adjacent outer fins and the auxiliary fins. Are both 5 mm or more and 8 mm or less.

  A tenth invention of the present application is an illuminating device including the heat sink according to any one of the first to ninth inventions, and a light source that is an object to be cooled disposed in the center of the lower surface of the substrate portion.

  According to 1st invention-10th invention of this application, in the heat sink which arrange | positions a to-be-cooled object in the center, a thermal radiation area can be increased, without narrowing the space | interval between fins. As a result, good heat dissipation efficiency can be obtained.

  In particular, according to the second invention of the present application, the rigidity in the vicinity of the radially outer end of the heat radiating portion can be improved.

  In particular, according to the third invention of the present application, the heat dissipation efficiency can be improved.

  In particular, according to the fourth to sixth inventions of the present application, it is possible to suppress an increase in channel resistance between the fins while increasing the heat radiation area in the intermediate fins.

It is sectional drawing of the illuminating device which concerns on 1st Embodiment. It is a perspective view of the heat sink concerning a 1st embodiment. It is a top view of the heat sink concerning a 1st embodiment. It is a perspective view of the heat sink concerning a 2nd embodiment. It is a top view of the heat sink concerning a 2nd embodiment. It is a perspective view of the heat sink concerning a 3rd embodiment. It is a top view of the heat sink concerning a 3rd embodiment. It is sectional drawing of the heat sink which concerns on 3rd Embodiment.

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

<1. First Embodiment>
<1-1. Configuration of lighting device>
FIG. 1 is a cross-sectional view of a lighting device 1 according to the first embodiment of the present invention. This illuminating device 1 is a ceiling-embedded LED downlight. The lighting device of the present invention is not limited to a ceiling-embedded downlight, and may be a spotlight or a standlight.

  The lighting device 1 includes an LED module 11, a hood portion 12, a cover 13, and a heat sink 20.

  The LED module 11 includes a base 111 and a substrate 112. The base 111 is made of metal and is formed in a disk shape. The substrate 112 is formed by mounting a COB (Chip On Board) type LED on the central portion of a substrate formed of glass or epoxy resin. The substrate 112 is fixed to the lower surface of the base 111.

  The upper surface of the base 111 is in contact with the lower surface of the heat sink 20. Thereby, heat generated in the LED mounted on the substrate 112 is transmitted to the heat sink 20 via the base 111. The contact surface between the base 111 and the heat sink 20 is preferably as smooth as possible. By smoothing the contact surfaces, the thermal coupling between the base 111 and the heat sink 20 is enhanced. Further, a material having high thermal conductivity such as silicon grease may be applied to the bonding surface between the base 111 and the heat sink 20. If it does so, the adhesion degree of adhesion surfaces will increase and the thermal coupling | bonding of the base 111 and the heat sink 20 will increase.

  The hood part 12 includes a frame part 121, a reflection part 122, and a lens 123. The frame part 121 is a cylindrical member extending in the vertical direction. The reflecting portion 122 is an umbrella-like member that is recessed from the lower end portion of the frame portion 121 toward the upper side. The reflector 122 reflects the light emitted from the LED chip. An opening 124 is provided at the upper end of the reflecting portion 122. The upper end of the reflecting portion 122 is fixed to the LED module 11 so that the LED mounted on the substrate 112 is exposed from the opening 124. The lens 123 is an optical component for adjusting the light distribution, which is disposed at the lower end of the frame 121. The frame part 121 and the reflection part 122 of this embodiment are die-cast products integrally formed of aluminum. In addition, the frame part 121 and the reflection part 122 may be shape | molded by a separate member.

  The cover 13 is a housing that houses the LED module 11, the hood portion 12, and the heat sink 20 therein. An opening for irradiating light from the LED module 11 to the outside is provided in the lower part of the cover 13. The cover 13 is fixed to the ceiling board by a fixture 131 provided on the outer peripheral surface thereof.

  The heat sink 20 is a heat radiating member formed of a material having a relatively high thermal conductivity such as aluminum, copper, or a copper alloy. In the present embodiment, an aluminum alloy is used as the material of the heat sink 20. When the lower surface of the heat sink 20 comes into contact with the upper surface of the base 111 of the LED module 11, the heat generated from the LED module 11 is dissipated into the surrounding gas through the heat sink 20. The detailed configuration of the heat sink 20 will be described later.

<1-2. Heat sink configuration>
Next, the configuration of the heat sink 20 will be described with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of the heat sink 20. FIG. 3 is a top view of the heat sink 20.

  As shown in FIGS. 2 and 3, the heat sink 20 includes a substrate part 21, a support part 22, and a heat dissipation part 23. In this embodiment, the board | substrate part 21, the support | pillar part 22, and the thermal radiation part 23 are integrally shape | molded by cold forging.

  The substrate part 21 is a disk-shaped part. In the center of the lower surface of the substrate unit 21, the LED module 11 that is an object to be cooled is disposed. The column portion 22 is a columnar portion that stands upward from the upper surface of the substrate portion 21 in the approximate center of the substrate portion 21. The support column 22 is disposed above the object to be cooled, so that the heat transmitted from the object to be cooled to the substrate unit 21 can be efficiently transmitted to the heat radiating unit 23 and can be radiated.

  The heat dissipating part 23 includes 12 inner fins 31, 24 intermediate fins 32, 24 outer fins 33, and 24 auxiliary fins 34. Each of these fins 31 to 34 is a plate-like heat radiating fin, and stands up from the substrate portion 21.

  The twelve inner fins 31 extend radially from the support column 22 outward in the radial direction. Each of the inner fins 31 has a wide portion 311 having a larger thickness in the circumferential direction than the other portion at the radially outer end thereof.

  Each of the intermediate fins 32 is bifurcated from the radially outer end of the inner fin 31 and extends radially outward. Of the intermediate fins 32, one that branches from the inner fin 31 to the one side in the circumferential direction is referred to as a first intermediate fin 321, and one that branches from the inner fin 31 to the other side in the circumferential direction is referred to as a second intermediate fin 322. In FIG. 3, the boundary between the inner fin 31 and the intermediate fin 32 is indicated by a broken line B1. Thus, the boundary between the inner fin 31 and the intermediate fin 32 is a branching point that is divided into two.

  Here, in this application, the direction in the circumferential direction in which an intermediate bending portion described later curves as it goes radially outward is referred to as a circumferential one side. In addition, the direction opposite to the one side in the circumferential direction is referred to as the other side in the circumferential direction. In the present embodiment, one side in the circumferential direction is a clockwise direction when viewed from above as shown in FIG. Further, the other side in the circumferential direction is a counterclockwise direction as viewed from above as shown in FIG.

  Each of the outer fins 33 extends radially outward from the radially outer end of each intermediate fin 32. In FIG. 3, the boundary between the intermediate fin 32 and the outer fin 33 is indicated by a broken line B2. Each of the auxiliary fins 34 is disposed substantially at the center in the circumferential direction of the outer fins 33 adjacent to each other in the circumferential direction, and extends in the radial direction along the outer fins 34.

  The twelve inner fins 31 are arranged at substantially equal intervals in the circumferential direction. The radially inner end of the inner fin 31 is connected to the support column 22 from the upper end to the lower end. Thereby, heat efficiently conducts from the LED module 11 disposed at the center of the lower surface of the substrate portion 21 to the inner fins 31 via the substrate portion 21 and the support column portion 22.

  Further, the lower end portion of the inner fin 31 is connected to the substrate portion 21. For this reason, heat is efficiently conducted from the object to be cooled disposed at the center of the lower surface of the substrate portion 21 to the inner fin 31 via the substrate portion 21.

  As shown in FIGS. 2 and 3, the inner fin 31 is thicker than the intermediate fin 32, the outer fin 33, and the auxiliary fin 34. Thereby, the heat transmitted from the LED module 11 to the substrate portion 21 and the column portion 22 can be efficiently conducted radially outward and upward. That is, the inner fin 31 can conduct heat to the intermediate fin 32 efficiently. Moreover, since the thickness of the wide part 311 is made larger than the other part of the inner side fin 31 as mentioned above, compared with the case where the thickness of the inner side fin 31 is substantially uniform, the radial direction of the 1st intermediate | middle fin 321 is sufficient. The space | interval of the circumferential direction of an inner end and the radial direction inner end of the 2nd intermediate | middle fin 322 can be taken large.

  The first intermediate fin 321 includes a first branch portion 41 that extends straight from the one end in the circumferential direction of the wide portion 311 to the radially outer side and one side in the circumferential direction, and a radially outer side from the radially outer end of the first branch portion 41. And an intermediate curved portion 42 extending to the center. The second intermediate fin 322 includes a second branch portion 43 extending straight from the other circumferential end of the wide portion 311 to the radially outer side and the other circumferential side, and a radially outer end from the radially outer end of the second branch portion 43. And an intermediate curved portion 44 extending to the front. In FIG. 3, the boundary between the first branch portion 41 and the intermediate bending portion 42 and the boundary between the second branch portion 43 and the intermediate bending portion 44 are indicated by a two-dot chain line B3.

  The intermediate curved portions 42 and 44 are curved in an arc shape toward one side in the circumferential direction as going outward in the radial direction. The curvatures of the intermediate curved portions 42 and 44 are larger than the maximum curvatures of the outer fins 33 and the auxiliary fins 34 and are substantially constant from the radially inner end to the radially outer end. The 24 intermediate curved portions 42 and 44 are arranged at substantially equal intervals in the circumferential direction. In this application, “curvature” refers to the reciprocal of the radius of curvature.

  Each of the outer fins 33 includes a first rectilinear portion 45 that extends straight from the radially outer end of the intermediate fin 32 to the radially outer side, and an outer curved portion 46 that extends radially outward from the radially outer end of the first rectilinear portion 45. Have. Each of the auxiliary fins 34 includes a second rectilinear portion 47 that extends straight in the radial direction and an outer curved portion 48 that extends radially outward from the radial outer end of the second rectilinear portion 47. The outer curved portions 46 and 48 are curved in an arc shape toward one side in the circumferential direction as going outward in the radial direction. That is, the outer curved portions 46 and 48 are curved in the same direction as the intermediate curved portions 42 and 44. In FIG. 3, the boundary between the first rectilinear portion 45 and the outer curved portion 46 and the boundary between the second rectilinear portion 47 and the outer curved portion 48 are indicated by a two-dot chain line B4.

  Thus, the outer fin 33 and the auxiliary fin 34 have substantially the same shape according to the radial position. However, the radially outer end of the second rectilinear portion 47 and the radially outer end of the first rectilinear portion 45 have substantially the same radial position, but the radially inner end of the second rectilinear portion 47 is the first It arrange | positions in the radial direction outer side from the radial direction inner end of the rectilinear advance part 45. FIG.

  The 24 outer fins 33 are arranged at substantially equal intervals in the circumferential direction. In addition, each auxiliary fin 34 is disposed at the substantially center in the circumferential direction of the outer fins 33 adjacent in the circumferential direction. That is, the 24 outer fins 33 and the 24 auxiliary fins 34 are alternately arranged at substantially equal intervals in the circumferential direction.

  Here, the gas flow around the heat sink 20 will be described with reference to FIG. In the present embodiment, the LED module 11 that is an object to be cooled is disposed at the center of the lower surface of the substrate portion 21 of the heat sink 20. Therefore, when the LED module 11 is driven and the LED module 11 generates heat, an ascending air current is generated around the center of the heat sink 20. Thereby, as shown by a solid line arrow and a broken line arrow in FIG. 3 as an example, an air flow is generated between the fins 31 to 34 of the heat sink 20 from the radially outer side to the radially inner side.

  As an example in FIG. 3, between the space A <b> 1 between the inner fins 31 adjacent in the circumferential direction, the surface on the one circumferential side of the first intermediate fin 321, and the surface on the other circumferential side of the second intermediate fin 322. The air flow generated in the space A2 is indicated by a solid line arrow. Further, a space A3 between the surface on one circumferential side of the outer fin 33 and the surface on the other circumferential side of the auxiliary fin 34, the surface on one circumferential side of the auxiliary fin 34, and the other circumferential surface of the outer fin 33 on the other circumferential side. The air flow generated in the space A4 between the surfaces is indicated by a solid arrow. The radial outer end of the space A1 and the radial inner end of the space A2, the radial outer end of the space A2 and the radial inner end of the space A3, the radial outer end of the space A2, and the radial inner end of the space A4 Each end is connected.

  When an upward air flow is generated upward from the heat sink 20, an air flow directed radially inward along the shapes of the inner fin 31 and the intermediate fin 32 is generated in the space A <b> 1 and the space A <b> 2. Thereby, gas is drawn in from the radial direction outer side of the heat sink 20, and the airflow which goes to space A3 and A4 radial inside is produced.

  Further, in FIG. 3, a space A5 between the surface on one circumferential side of the second intermediate fin 322 and the surface on the other circumferential side of the first intermediate fin 321 and the surface on one circumferential side of the outer fin 33. And the airflow generated in the space A6 between the surfaces on the other circumferential side of the auxiliary fin 34 and the space A7 between the surface on the one circumferential direction of the auxiliary fin 34 and the surface on the other circumferential side of the outer fin 34, It is indicated by a dashed arrow. The radially outer end of the space A5 and the radially inner end of the space A6 are connected to the radially outer end of the space A5 and the radially inner end of the space A7, respectively.

  In the present embodiment, as described above, the radially inner end of the auxiliary fin 34 is disposed on the radially outer side than the radially inner end of the outer fin 33. As a result, in the vicinity of the connection portion between the intermediate fin 32 and the outer fin 33, the airflow in the space A3 and the airflow in the space A4 are easily joined and headed toward the space A2. Similarly, in the vicinity of the connection portion between the intermediate fin 32 and the outer fin 33, the airflow in the space A6 and the airflow in the space A7 are easily merged and headed toward the space A5. That is, the flow path resistance of the gas flowing between the fins 31 to 34 can be reduced.

  Like the heat sink 20, in the heat sink in which the object to be cooled is disposed substantially in the center, the heat from the object to be cooled is easily conducted toward the inside in the radial direction, and the cooling efficiency is high. Therefore, it is preferable to increase the surface area of the inner fin 31 and the intermediate fin 32. However, when the number of the inner fins 31 and the intermediate fins 32 is simply increased, the interval between the fins 31 and 32 is narrowed, and the flow resistance of the gas flowing between the fins 31 and 32 is increased. In that case, since the speed of the airflow flowing between the fins 31 and 32 becomes slow, there is a possibility that the cooling efficiency cannot be improved even if the inner fin 31 and the intermediate fin 32 have a large surface area. Therefore, it is preferable to increase the surface area of the inner fin 31 and the intermediate fin 32 without reducing the interval between the fins 31 to 34.

  Therefore, in the heat sink 20, the intermediate fin 32 branches off from the inner fin 31. Thereby, it is possible to reduce the number of inner fins 31 that are arranged on the innermost side in the radial direction and in which fins tend to be densely packed. Therefore, it is suppressed that the space | interval of inner fins 31 becomes narrow. Further, the intermediate fin 32 has intermediate curved portions 42 and 44. Thereby, the surface area in the intermediate fin 32 can be increased without narrowing the space between the intermediate fins 32. That is, good heat dissipation efficiency can be obtained. Further, since the intermediate fin 32 has the intermediate curved portions 42 and 44, the rigidity of the intermediate fin 32 is improved.

  In the heat sink 20, the outer fins 33 and the auxiliary fins 34 have outer curved portions 46 and 48 at their radially outer ends. Thereby, the rigidity of the outer fin 33 and the auxiliary fin 34 is improved. On the other hand, as described above, the intermediate curved portions 42 and 44 have a curvature larger than the maximum curvature of the outer fin 33 and the auxiliary fin 34. That is, the curvatures of the outer curved portions 46 and 48 are smaller than the curvatures of the intermediate curved portions 42 and 44. As described above, since the bending of the outer curved portions 46 and 48 is small, an increase in the channel resistance in the vicinity of the outer fin 33 and the auxiliary fin 34 is suppressed. Thereby, it is suppressed that the speed of the air current in the vicinity of the inner fin 31 and the intermediate fin 32 decreases. That is, the heat radiation efficiency in the inner fin 31 and the intermediate fin 32 can be improved.

  The heat sink 20 of this embodiment has a diameter of 125 mm. The length in the radial direction of one intermediate fin 32 is 21 mm. For this reason, the ratio that the intermediate fins 32 occupy in the radial direction with respect to the diameter of the heat radiating portion 23 is 33.6%. When the intermediate fins 32 are lengthened, the heat radiation area is increased, while the flow path resistance of the heat radiation portion 23 as a whole is increased. Therefore, as described above, it is preferable that the ratio of the intermediate fins 32 in the radial direction is 30% or more and 40% or less with respect to the diameter of the heat dissipation portion 23. Thereby, the increase in flow path resistance can be suppressed while increasing the heat radiation area.

  The length of one outer fin 33 in the radial direction is 25 mm. For this reason, the proportion of the outer fins 33 in the radial direction with respect to the diameter of the heat radiating portion 23 is 40%. If the outer fins 33 are lengthened, gas can be easily drawn from the radially outer side of the heat radiating portion 23. On the other hand, if the outer fin 33 is lengthened, the length of the intermediate fin 32 having the highest heat dissipation efficiency cannot be made long. Thus, as described above, it is preferable that the ratio of the outer fins 33 in the radial direction with respect to the diameter of the heat radiating portion 23 is 35% or more and 45% or less.

  In the heat sink 20 of this embodiment, the number of inner fins 31 is twelve, and the number of intermediate fins 32, outer fins 33, and auxiliary fins 34 is all twenty-four. Thereby, the space | interval of adjacent intermediate | middle curved part 43 and the space | interval of the adjacent outer side fin 33 and the auxiliary | assistant fin 34 become about 6-7 mm. As described above, in the heat sink 20 having a diameter of 100 mm to 200 mm, the interval between the adjacent intermediate curved portions 43 and the interval between the adjacent outer fin 33 and the auxiliary fin 34 are both 5 mm or more and 8 mm or less. preferable. If it does so, the fall of the speed of the airflow between the fins 31-34 can be suppressed efficiently.

  Further, in the heat sink 20 of the present embodiment, a straight line connecting the center 220 of the column part 22 and the inner end of the intermediate curved part 43 and a straight line connecting the center 220 of the column part 22 and the outer end of the intermediate curved part 43. The angle formed is about 26 °. When the circumferential positions of the inner end and the outer end of the intermediate curved portion 43 are greatly different, the flow path resistance in the vicinity of the intermediate curved portion 43 increases. Therefore, in this way, the angle formed by the straight line connecting the center 220 of the support column 22 and the inner end of the intermediate bending portion 43 and the straight line connecting the center 220 of the support column 22 and the outer end of the intermediate bending portion 43, The angle is preferably 15 ° or more and 40 ° or less. Thereby, the increase in flow path resistance can be suppressed while increasing the heat radiation area in the intermediate curved portion 43.

<2. Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a perspective view of a heat sink 20A according to the second embodiment. FIG. 5 is a top view of the heat sink 20A.

  As shown in FIGS. 4 and 5, the heat sink 20A includes a substrate portion 21A, a support column portion 22A, and a heat dissipation portion 23A. The heat radiating portion 23A includes a plurality of inner fins 31A, a plurality of intermediate fins 32A, a plurality of outer fins 33A, and a plurality of auxiliary fins 34A. In FIG. 5, the boundary between the inner fin 31A and the intermediate fin 32A is indicated by a broken line C1, and the boundary between the intermediate fin 32A and the outer fin 33A is indicated by a broken line C2.

  The plurality of inner fins 31 </ b> A extend radially outward in the radial direction with the support post 22 </ b> A as the center, and are arranged at substantially equal intervals in the circumferential direction. Each of the intermediate fins 32A is bifurcated from the radially outer end of the inner fin 31A and extends radially outward. Of the plurality of intermediate fins 32A, the one that branches from each inner fin 31A to the one circumferential side is referred to as a first intermediate fin 321A, and the one that branches from each inner fin 31A to the other circumferential side is the second intermediate fin 322A. Called.

  Here, in the present embodiment, intermediate curved portions 42A and 44A, which will be described later, are curved toward the radially outer side, and the direction in the circumferential direction is a counterclockwise direction when viewed from above. Therefore, “one side in the circumferential direction” in the present embodiment is a counterclockwise direction when viewed from above.

  Each of the first intermediate fins 321A has a first branch portion 41A extending straight from the inner fin 31A to the radially outer side and the other circumferential side, and an intermediate curved portion 42A extending radially outward from the radially outer end of the first branch portion 41A. And have. Each of the second intermediate fins 322A includes a second branch portion 43A that extends straight from the inner fin 31A to the radially outer side and one circumferential side, and an intermediate curved portion 44A that extends radially outward from the radially outer end of the second branch portion 43A. And have. The intermediate bending portions 42A and 44A are curved in an S shape toward the one side in the circumferential direction as going outward in the radial direction. In FIG. 5, the boundary between the first branch portion 41A and the intermediate curved portion 42A and the boundary between the second branch portion 43A and the intermediate curved portion 44A are indicated by a two-dot chain line C3.

  Each of the outer fins 33A extends radially outward from the radially outer end of the intermediate fin 32A. A part of the outer fin 33A including the radially outer end is curved in an arc shape toward the other side in the circumferential direction toward the radially outer side. That is, the outer curved portions 46A and 48A are curved in the opposite direction to the intermediate curved portions 42A and 44A. As a result, the continuous inner fin 32A and outer fin 33A are integrally bent in an S shape. Each of the auxiliary fins 34A is disposed substantially at the center in the circumferential direction of the outer fins 33A adjacent in the circumferential direction, and extends in the radial direction along the adjacent outer fins 33A. That is, a part of the auxiliary fin 34A including the radially outer end is curved in an arc shape toward the other circumferential side as it goes radially outward. As shown in FIG. 5, the maximum curvatures of the intermediate curved portions 42A and 44A are larger than the maximum curvatures of the outer fins 33A and the auxiliary fins 34A.

  In the heat sink 20A of the present embodiment, the intermediate curved portions 42A and 44A of the intermediate fin 32A are curved in an S shape. For this reason, a corner | angular part does not arise in the connection location of the intermediate | middle fin 32A and the outer side fin 33A. Therefore, the airflow directed radially inward between the outer fins 33A and the auxiliary fins 34A can smoothly flow into the space between the intermediate fins 32A. That is, the flow path resistance at the connection point between the intermediate fin 32A and the outer fin 33A can be reduced. Further, in the heat sink 20A of the present embodiment, the radially inner end of the auxiliary fin 34A is disposed on the radially inner side of the radially inner end of the outer fin 33A. Thus, the auxiliary fin 34A may be longer than the outer fin 33A.

<3. Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a perspective view of a heat sink 20B according to the third embodiment. FIG. 7 is a top view of the heat sink 20B. FIG. 8 is a cross-sectional view taken along line AA of the heat sink 20B.

  This heat sink 20B is different from the heat sink 20 according to the first embodiment only in the shapes of the support portion 22B and the inner fin 31B. Description of the configuration of the heat sink 20B that is the same as that of the heat sink 20 according to the first embodiment is omitted.

  As shown in FIGS. 6 and 7, the strut portion 22B of the heat sink 20B has a larger diameter than the strut portion 22 of the first embodiment. Correspondingly, the inner fin 31B has a shorter radial length than the inner fin 31 of the first embodiment. Moreover, as shown in FIGS. 6-8, the support | pillar part 22B has the recessed part 221B recessed toward the downward direction from an upper surface. In FIG. 8, the boundary between the substrate portion 21B, the support column portion 22B, and the heat radiation portion 23B, and the boundary between the support column portion 22B and the inner fin 31B are indicated by broken lines.

  In the present embodiment, the heat sink 20B is formed by cold forging. When forming a heat sink by cold forging, it is preferable to make the pressure concerning each part as uniform as possible. In order to make the pressure uniform, it is conceivable to reduce the diameter of the support column or to provide a recess in the support column so that the support column has an annular shape. However, if the diameter of the column part is reduced, the cross-sectional area of the connection portion between the column part and the substrate part is reduced, so that the thermal conductivity from the LED module to the column part is lowered and the heat radiation efficiency is lowered. In addition, if the concave portion is provided to the lower end of the support column, the volume of the connection part of the support column to the substrate unit is reduced, and the heat capacity that can be stored is reduced. Efficiency is reduced.

  Therefore, as shown in FIG. 8, in the heat sink 20B of the present embodiment, a recess 221B is provided in the support column 22B. That is, the column portion 22B includes a columnar column portion 222B and an annular portion 223B formed in an annular shape around the recess 221B on the upper side of the column portion 222B.

  Since the cylindrical portion 222B having a large horizontal sectional area is connected to the substrate portion 21B, heat is efficiently conducted from the LED module to the cylindrical portion 222B through the substrate portion 21B. Further, by providing the annular portion 223B in which the concave portion 221B is disposed, it is possible to suppress a decrease in the molding accuracy of the heat sink 20B.

  In the present embodiment, the vertical length of the recess 221B is about 58.3% of the vertical length of the support column 22B. Thus, by making the vertical length of the concave portion 221B be 50% or more and 70% or less, it is possible to improve the heat conduction efficiency from the LED module to the column portion 22B and to suppress a decrease in the molding accuracy of the heat sink 20B. .

  In addition, the recessed part 221B may extend to the lower end part of the support | pillar part 22B. In that case, it is preferable to fill a part including at least the lower end portion of the concave portion 221B with a material having high thermal conductivity such as a high thermal conductive resin. If it does so, the fall of the shaping accuracy of heat sink 20B can further be controlled, suppressing the fall of the heat conduction efficiency from LED module to supporter part 22B.

<4. Modification>
As mentioned above, although main embodiment of this invention was described, this invention is not limited to said embodiment.

  In the above embodiment, the outer fin and the auxiliary fin have the outer curved portion, but the present invention is not limited to this. The outer fin and the auxiliary fin may be configured by only the first rectilinear portion and the second rectilinear portion that are not curved and extend straight in the radial direction.

  In the above embodiment, the heat sink cools the LED module, but the present invention is not limited to this. The heat sink of the present invention may cool other objects to be cooled, such as electronic components, that generate a large amount of heat.

  In the above embodiment, the inner fin, the intermediate fin, and the outer fin are continuously formed from the support column to the outer periphery of the heat sink, but the present invention is not limited to this. For example, an inner fin, an intermediate fin, an outer fin, and a connection portion between the fins may be provided with a gap that is divided in the radial direction or a cut that extends downward from the upper end.

  Moreover, in this invention, the bending direction of each fin is not limited to the example of said embodiment. The bending direction of the intermediate bending portion and the outer bending portion may be the same direction or may be opposite directions. In addition, each fin may be curved in the opposite direction to the above-described embodiment and may have the same shape as the mirror image of the above-described embodiment.

  In the present invention, the number of fins is not limited to the example of the above embodiment. The number of fins is preferably adjusted as appropriate depending on the diameter of the heat radiating portion, the type of material, the thickness of each fin, and the like.

  Moreover, you may combine arbitrarily each element which appeared in said each embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Illuminating device 11 LED module 20,20A, 20B Heat sink 21,21A, 21B Substrate part 22,22A, 22B Support | pillar part 23,23A, 23B Radiating part 31,31A, 31B Inner fin 32,32A Intermediate fin 33,33A Outer fin 34, 34A Auxiliary fins 42, 42A, 44, 44A Intermediate curved part 46, 46A, 48, 48A Outer curved part 220 Center 221B Recessed part

To solve the above problems, a first invention of the present application, radiator having a plate-shaped substrate section object to be cooled is placed in the center of the lower surface, the upright plate-shaped fins upwardly from the front Stories substrate portion includes a part, wherein the plurality of fins includes an intermediate fin multiple, and a plurality of outer fins which are placed radially outside the radially outer end of the previous SL intermediate fins, said intermediate fins has an intermediate curved portion that is curved to one circumferential direction toward the radially outer side, the maximum curvature of the front Symbol intermediate curved portion is greater than the maximum curvature of the outer Fi down a heat sink.

The second invention of the present application relates to a heat sink of the first invention, the outer Fi down the outer curvature curving either one and the same direction in one circumferential direction and the other circumferential side toward the radially outer side Part.

A third invention of the present application is the heat sink of the first invention or the second invention, wherein the plurality of fins further includes a plurality of inner fins inside the substrate than a radially inner end of the intermediate fin, The plurality of intermediate fins are bifurcated from the radially outer end of the inner fin and extend radially outward .

A fifth invention of the present application is the heat sink according to any one of the first to fourth inventions, wherein the straight line connecting the center of the substrate portion and the inner end of the intermediate curved portion, the center of the support column portion, and the intermediate portion. The angle formed by the straight line connecting the outer end of the curved portion is 15 ° or more and 40 ° or less .

A sixth invention of the present application is the heat sink according to any one of the first to fifth inventions, and includes a columnar column portion standing upward from the center of the substrate portion, and the column portion is downward from the upper surface. It has a concave part that is recessed .

A seventh invention of the present application is the heat sink according to any one of the first to sixth inventions , wherein the intermediate fin and the outer fin are provided with a gap between the intermediate fin and the outer fin. Therefore, it is divided in the radial direction .

An eighth invention of the present application is an illuminating device including the heat sink according to any one of the first to seventh inventions, and a light source that is an object to be cooled disposed in the center of the lower surface of the substrate portion.

According to the first to eighth inventions of the present application, in the heat sink in which the object to be cooled is arranged in the center, the heat radiation area can be increased without narrowing the interval between the fins. As a result, good heat dissipation efficiency can be obtained.

In particular, according to the fourth and fifth inventions of the present application, it is possible to suppress an increase in flow resistance between the fins while increasing the heat radiation area of the intermediate fins.

Claims (10)

A plate-like substrate portion in which an object to be cooled is arranged at the center of the lower surface;
A column-shaped column portion standing upward from the upper surface of the substrate portion;
A heat radiating portion having a plurality of plate-like fins erected upward from the substrate portion;
Have
The plurality of fins are:
A plurality of inner fins extending radially outward in the radial direction centered on the support column and disposed at substantially equal intervals in the circumferential direction;
A plurality of intermediate fins bifurcated from the radially outer end of the inner fin and extending radially outward;
A plurality of outer fins extending radially outward from the radially outer end of the intermediate fin and arranged at substantially equal intervals in the circumferential direction;
A plurality of auxiliary fins arranged in the circumferential center of the outer fins adjacent in the circumferential direction and extending in the radial direction;
Including
The intermediate fin has an intermediate bending portion that curves toward one side in the circumferential direction as it goes radially outward,
The plurality of intermediate curved portions are arranged at substantially equal intervals in the circumferential direction,
The maximum heat sink of the said intermediate | middle curved part is a heat sink larger than the maximum curvature of the said outer side fin and the said auxiliary | assistant fin. The heat sink according to claim 1,
The outer fin and the auxiliary fin have an outer curved portion that is curved in either the same direction or the circumferential one side and the other circumferential side as going radially outward. A heat sink according to claim 1 or claim 2,
The radially outer end of the support column and each radially inner end of the inner fin are formed in a continuous manner,
A heat sink, wherein the radially outer ends of the inner fins and the radially inner ends of the two intermediate fins branched from the inner fins are connected together. A heat sink according to any one of claims 1 to 3,
The ratio that the intermediate fin occupies in the radial direction with respect to the diameter of the heat radiating portion is 30% or more and 40% or less. A heat sink according to any one of claims 1 to 4,
The proportion of the outer fin in the radial direction with respect to the diameter of the heat radiating portion is 35% or more and 45% or less. A heat sink according to any one of claims 1 to 5,
An angle formed by a straight line connecting the center of the support column and the inner end of the intermediate bending portion and a straight line connecting the center of the support column and the outer end of the intermediate bending portion is 15 ° or more and 40 ° or less. ,heatsink. A heat sink according to any one of claims 1 to 6,
The said support | pillar part is a heat sink which has a recessed part dented toward the downward direction from an upper surface. A heat sink according to any one of claims 1 to 7,
The number of the inner fins is twelve;
The heat sink, wherein the number of intermediate fins, the number of outer fins, and the number of auxiliary fins are all 24. A heat sink according to any one of claims 1 to 8,
The heat sink, wherein both the interval between the curved portions of the adjacent intermediate fins and the interval between the adjacent outer fin and the auxiliary fin are 5 mm or more and 8 mm or less. A heat sink according to any one of claims 1 to 9,
A light source that is an object to be cooled disposed in the center of the lower surface of the substrate portion;
A lighting device.

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