JP5608152B2 - Heat sink for in-vehicle LED lighting - Google Patents

Description

  The present invention relates to a heat sink for LED lighting, in which LED lighting using a light emitting diode (LED) element as a light source radiates heat generated during light emission to the surrounding space.

  Lighting that uses a light emitting diode (LED) element as a light source is gradually penetrating the market due to its low power consumption and long life. Among these, in-vehicle LED lighting (vehicle lamps, vehicle headlamps) such as automobile headlights has attracted particular attention in recent years, and replacement with LED elements has begun. In addition, by applying this in-vehicle LED lighting, replacement with LED lighting has begun in embedded lighting in other fields such as buildings.

  However, the LED element which is a light emitting source of this LED illumination is very weak to heat, and there is a problem that when the temperature exceeds the allowable temperature, the light emission efficiency is lowered, and further, the life is affected. In order to solve this problem, since it is necessary to dissipate heat at the time of light emission of the LED element to the surrounding space, the LED lighting is provided with a large heat sink.

  Many LED lighting heat sinks made of aluminum (including an aluminum alloy) by die-casting or extrusion are used. For example, Patent Documents 1 to 3 show representatives of these. A typical heat sink configuration is disclosed. These heat sinks have a substrate part in which the LED light source is arranged and fixed on the front side, and a plurality of parallelly arranged fin parts protruding at intervals on the back side of the substrate part. In addition, by increasing the surface area of the fin portion, the heat dissipation increases, and a certain heat dissipation property can be obtained.

  On the other hand, heat sinks that have been further reduced in weight and cost have been proposed. For example, Patent Document 4 proposes a heat sink formed by bending a metal plate having a high thermal conductivity such as aluminum as a heat sink of a vehicle lamp. This heat sink is made by bending a flat metal plate with a thickness of about 1 mm to 3 mm into a ladle cross section, and a heat radiating portion of a ladle portion with a U-shaped vertical cross section and an LED light source with a ladle handle portion with a vertical cross section. And a supporting part for supporting. The overall shape of the heat sink is such that a large number of slit-like openings obtained by chopping the heat dissipating part at regular intervals are provided in the longitudinal direction (or width direction), and a large number of narrow openings and narrow widths are provided. The heat dissipating part is a comb tooth shape alternately arranged in parallel.

JP 2007-193960 A JP 2009-277535 A JP 2010-278350 A JP 2010-146817 A

  The basic structure of the conventional heat sink H by the die-casting or the extruded profile is as shown in FIG. 6, a substrate portion 30 with an LED element (light source) L arranged and fixed on the front side, and the substrate portion 30. A plurality of parallelly arranged fin portions 40 projecting at an interval on the back side of the housing, and this is incorporated in a housing and used for in-vehicle lighting such as an automobile headlight and tail lamp. In this case, it is installed in a limited narrow space.

  For this reason, the heat radiation space where the substrate part 30 and the fin part 40 are located is also in a closed volume and there is almost no air convection, so in such an installation environment almost no heat dissipation by convection can be expected, Heat dissipation by radiation is the center, and the heat sink structure in which the heat radiation side area is increased by fins or the like as in the prior art has a problem that heat radiation by radiation is insufficient, and efficient heat dissipation cannot be achieved as a whole.

  That is, in the case of radiation, the size of the projected area in the X, Y, and Z axis directions (three-dimensional directions) displayed in the lower right of FIG. 6 affects the efficiency. Radiation efficiency will be improved. In this regard, in the heat sink of FIG. 6, the projected area in the Y direction may be the sum of the plane of the substrate portion 30 and the plane of the fin portion 40. However, the projected area in the Z direction is a comb-like shape with a total of the side surface of the substrate unit 30 and the side surface of the fin unit 40, and has a large space. Therefore, the total area obtained by multiplying the length of the substrate unit 30 and the height of the fin unit 40 is The area is less than 50%. Further, the projected area in the X direction is the total of the front surface of the substrate portion 30 and the front surface of the fin portion 40. Even though there are, for example, four fin portions 30, these overlap and have the same projected area as one. Yes, radiation efficiency per area on the heat radiation side is low.

  On the other hand, the heat sink formed by bending the metal flat plate can be lighter than the conventional heat sink H made of the die-cast or extruded profile shown in FIG. In addition, since the slit-shaped opening is provided adjacent to the heat radiating portion, air convection through the lamp chamber flows into the heat radiating portion, and at the same time, air flows through the opening. The heat dissipation efficiency can be improved by the generation of the air flow (convection).

  However, it is difficult to increase the dimensional accuracy of the heat sink formed by bending the metal flat plate, due to the springback that is inevitably generated in the bending process, and additional bending is required to ensure dimensional accuracy. In addition, precision is also required for the cutting process that provides the large number of narrow slit-like openings, and a process of joining some surfaces after bending a metal plate as a material is also required. is there. Therefore, the cost is higher than that of the die-cast or extruded profile shown in FIG. The width of the slit-like opening is inevitably narrow due to a large restriction for ensuring the size of the heat sink itself and the area on the side of the heat dissipation part. For this reason, when applied and installed in a closed space such as a vehicular lamp, the improvement in heat dissipation efficiency due to the convection of the air is not exhibited as expected.

  The present invention has been made in view of such problems, and the object of the present invention is that it can be manufactured from an aluminum plate by a relatively simple processing method, and there is no or little convection due to air (air Heat radiation for LED lighting that has a radiation-based heat dissipation property that can efficiently radiate heat from the LED light source even when installed in a closed space. Is to provide.

In order to achieve the above-mentioned object, the gist of the in- vehicle LED lighting heat sink of the present invention is that the LED element mounting surface and the heat radiating side surface continuous with the LED element mounting surface are integrated and continuous by drawing a single aluminum sheet. A heat sink for in- vehicle LED lighting formed, wherein the LED element mounting surface is a top portion and the heat radiating side surface is a barrel portion formed in a rectangular tube shape, and an opening in an internal space surrounded by these surfaces is also provided It is formed into a hollow rectangular cylindrical body having a radiation heat radiation surface continuously directed in any of the three dimensions by the front and back surfaces of the LED element mounting surface and the heat radiation side surface. That is.

  According to the present invention, it is possible to obtain a heat sink for LED lighting in which an LED element mounting surface and a heat radiating side surface are continuously and integrally formed from one metal thin plate by drawing. Thus, the shape of the heat sink formed by drawing is a cylindrical body in which the LED element mounting surface is the top and the heat radiating side is the body, and the front and back surfaces of the LED element mounting surface and the heat radiating side are 3 A cylindrical body continuously having a heat radiating surface facing in any direction of the dimension can be obtained. At the same time, an opening can be provided in the internal space of the cylindrical body.

  Thereby, it is possible to dissipate heat conducted from the LED elements installed on the LED element mounting surface from the continuous front and back surfaces facing in any of the three-dimensional directions. Therefore, even in a space where the projected area in the three-dimensional direction of the heat sink is large, and therefore there is little or no convection due to air with its application and installation location (place) closed (almost no heat dissipation due to air convection) Heat from the LED light source can be efficiently radiated. Therefore, the heat sink can be a radiation-based heat radiation rather than air convection, and the heat radiation can be advantageously improved as a whole.

Further, the present invention is a heat sink having a cylindrical body structure integrally formed by drawing from a thin metal plate such as an aluminum thin plate. Therefore, it is only necessary to draw a thin sheet such as a sheet or a coil, or a thin sheet processed by extrusion or the like, which is generally used for forming the thin sheet (including trimming and the like in a series of drawing processes). The shape and structure can be integrally formed and manufactured relatively easily.
Furthermore, since the metal thin plate is drawn using a press die, the spring back that occurs in the bending process hardly occurs, and high dimensional accuracy can be obtained. Further, in the present invention, the heat sink has no obstacle such as a slit that divides the heat conduction path as in the prior art. For this reason, the heat conduction path in the heat sink is not divided, and heat from the LED element is transmitted to each part constituting the heat sink, so that extremely high heat dissipation is ensured. Moreover, since it is an integral structure formed by drawing, high component rigidity and strength are also realized.

  Furthermore, since the present invention is made of a light metal thin plate, the heat sink of the cylindrical body structure can be reduced in weight as compared with the die-casting or casting, and can be used for LED lighting such as in-vehicle use. Suitable as a heat sink.

It is a perspective view which shows one aspect | mode of this invention heat sink. It is a perspective view which shows the other aspect of this invention heat sink. It is a perspective view which shows the other aspect of this invention heat sink. It is a perspective view which shows the other aspect of this invention heat sink. It is explanatory drawing which shows the processing method of this invention heat sink. It is a perspective view which shows the conventional heat sink.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol. Here, the embodiment of FIG. 1 is a reference example that is out of the scope of the present invention. Further, the following description “metal sheet” refers to an aluminum sheet.

(FIG. 1, one embodiment of heat sink)
In FIG. 1, one Embodiment of the heat sink 1 for LED illumination of this invention is shown. As shown in FIG. 1, a heat sink 1 for LED lighting of the present invention is formed by integrally forming a thin metal plate 1 having a certain plate thickness, such as aluminum, for example, and has a hollow cylindrical shape (cylindrical cup shape) as a whole. It has the three-dimensional shape. That is, the LED illumination heat sink 1 of the present invention shown in FIG. 1 is formed by integrally and continuously forming the LED element mounting surface 2 and the heat radiating side surface 3 from one metal thin plate by drawing.

  More specifically, in the case of the heat sink 1 of FIG. 1, the LED element mounting surface 2 is a disk (disk) -shaped top portion, and the heat radiating side surface 3 is connected to the cylindrical (circular tubular) body portion (side portion). It is formed to be. For this reason, the LED element mounting surface 2 and the heat radiating side surface 3 each have two continuous surface-side surfaces (outer surface = surface) 2a, 3a facing in any of three-dimensional X, Y, and Z directions. In addition, a total of four heat radiation surfaces, that is, two surfaces on the back side (inner surface = back surface) 2b and 3b are formed. Hereinafter, the side surface of the cylindrical body connected to the LED element mounting surface is referred to as a heat radiating side surface, and the heat radiating side surface and the surface capable of radiating heat such as the LED element mounting surface are referred to as a heat radiating surface.

  10 on the bottom side of the cylindrical body is a space where no heat dissipation surface exists, and an internal space surrounded by the LED element mounting surface 2 and the heat dissipation side surface 3 of the cylindrical body is opened to the outside. (Space part). Since the heat sink 1 in FIG. 1 is cylindrical, the opening 10 has the same area as the LED element mounting surface 2 when the angle formed by the LED element mounting surface 2 and the heat radiating side surface 3 is 90 degrees, for example. . For this reason, it has a comparatively large area with respect to the heat radiation side area of the heat sink 1, and the air in the internal space and the outside air convect inside and outside the heat sink 1 through the opening 10. The structure is sufficient. Such an opening includes not only the bottom side of the cylindrical body but also the bottom side of the cylindrical body, or instead of the bottom side of the cylindrical body, including other embodiments described later. Although it may be provided on the LED element mounting surface 2, if the opening is too large, heat conduction from the LED element to the heat radiation side will be hindered. If provided, it should be applied in a limited manner. Therefore, when an opening is selectively provided on the LED element mounting surface, it is preferable to use a slit-like relatively small opening having a width of about 5 mm at the maximum.

  Here, the angle formed by the LED element mounting surface 2 and the heat radiating side surface 3, that is, the inclination of the cylindrical body portion (side portion) is determined according to the design conditions of the heat sink 1, and is not necessarily 90 degrees. The longitudinal section of the cylindrical body of the heat sink 1 may be trapezoidal in which either the LED element mounting surface 2 or the opening 10 is large. However, in any case, it is necessary to secure a sufficient area for exciting or inducing convection of air inside and outside the heat sink 1, which is a function of the opening 10.

  In the case of FIG. 1, it has a shape having a flat disk-shaped LED element mounting surface 2 and a heat radiating side surface 3 forming a cylindrical curved surface, and both are formed by drawing from a single aluminum plate. Therefore, the LED element mounting surface 2 and the heat radiating side surface 3 are integrally continuous with the ridgeline of the LED element mounting surface 2 end (corner portion). In other words, the front and back surfaces 2a, 2b, 3a, and 3b of the LED element mounting surface 2 and the heat radiating side surface 3 are continuous by the LED element L installed on the top LED element mounting surface 2 and a single metal thin plate. ing.

  Here, the LED element mounting surface 2 faces in the Y direction in FIG. 1, the front surface 2a of the LED element mounting surface 2 faces upward in the drawing, and the back surface 2b of the LED element mounting surface 2 faces downward in the drawing. . Moreover, since the heat radiating side surface 3 is cylindrical, both the front surface 3a and the back surface 3b of the heat radiating side surface 3 are oriented in the X direction and the Z direction (lateral direction). For this reason, the LED element mounting surface 2 and the heat radiating side surface 3 together constitute a heat radiating surface facing in any of the three-dimensional X, Y, and Z directions.

  With the configuration described above, the heat sink 1 for LED illumination of the present invention is directly transmitted from the LED element L to each of the surfaces 2a, 3a, 2b, and 3b, and the three-dimensional direction of the heat toward each surface. Heat radiation in any of X, Y, and Z directions is possible.

(Principles of heat dissipation, effects)
The principle (action) of heat dissipation when LED lighting is performed by installing the heat sink 1 having such a cylindrical cup shape in a space free from air convection will be described. When the LED element L mounted on the LED element mounting surface 2 emits light, the heat generated by the LED element L is transmitted to the LED element mounting surface 2 through a mounting portion (not shown) at the bottom of the LED element L. Is done. Subsequently to this, the heat conducted to the LED element mounting surface 2 is conducted to the heat radiation side surface 3.

  The heat Q transmitted to the LED element mounting surface 2 is radiated from the entire surface 2a and back surface 2b of the flat surface of the mounting surface 2 to the surrounding closed space (heat radiation space). As described above, the LED element mounting surface 2 faces in the Y direction (vertical direction) in FIG. 1, the front surface 2a of the LED element mounting surface 2 is upward, and the back surface 2b of the LED element mounting surface 2 is lower in the figure. Facing the direction. Therefore, the heat Q is outside the cylindrical structure in the direction perpendicular to the heat transfer direction (X and Z directions in FIG. 1 where the mounting surface 2 extends) (Y direction in FIG. 1 = vertical direction). And inside each enclosed space (heat dissipating space).

  Moreover, the heat radiating side surface 3 is cylindrical as described above, and both the front surface 3a and the back surface 3b of the heat radiating side surface 3 are oriented in the X direction and the Z direction (lateral direction in FIG. 1). Therefore, the heat Q transmitted to the heat radiating side surface 3 is transferred from the entire surface 3a and back surface 3b of the flat surface of the heat radiating side surface 3 to the heat transfer direction (Y direction in FIG. 1 where the heat radiating side surface 3 extends). In the perpendicular direction (X, Z direction = horizontal direction in FIG. 1), the light is radiated to the closed space (heat radiation space) around the outside and inside of the cylindrical structure.

  Therefore, the heat generated by the LED element L is radiated in any of the three-dimensional X, Y, and Z directions. The heat radiation from the back surface 2b of the LED element mounting surface 2 and the back surface 3b of the heat radiation side surface 3 is heat radiation to the internal space surrounded by the cylindrical (cup) -shaped heat radiation side surface 3. For this reason, heat radiation by convection from these surfaces is of course performed, and by convection inside and outside the heat sink 1 through the opening 10 between the air inside the cylindrical body and the outside air. Heat dissipation to the outside of the heat sink 1 is also guaranteed. However, since the heat radiated to the internal space is absorbed by the back surface portion of the heat radiating side surface 3 facing, the amount of heat radiated is smaller than the heat radiated from the surface 3a on the surface side (outside) of the heat radiating side surface 3. .

  As described above, the heat sink 1 having the cylindrical shape (cup shape) of FIG. 1 and including the LED element mounting surface 2 and the heat radiating side surface 3 constituting the cup shape is air whose heat dissipation efficiency is governed by radiation. Even in a closed heat radiating space in a lighting fixture with little convection, the projected area in the X, Y, Z direction, that is, the three-dimensional direction, is very large. For this reason, radiation efficiency is high and it has excellent heat dissipation. Further, since the projected area of the heat sink 1 does not overlap in the radiation direction to the heat radiation space, the heat radiation efficiency per heat radiation unit area is good while being a simple structure that can be easily drawn (formed).

  That is, the heat sink of the present invention is optimal in a usage (installation) environment in which the surrounding heat radiation space is closed and the volume is small and there is almost no air convection, and heat radiation due to air convection is hardly expected. is there. In such a use environment, for heat dissipation, it is necessary to focus on heat dissipation by radiation, and in the conventional heat sink structure, which is mainly heat dissipation performance of convection of air by increasing the surface area of the heat dissipation surface such as fins, Heat radiation due to this radiation becomes insufficient, and efficient heat radiation cannot be achieved as a whole. On the other hand, the heat sink of the present invention is a heat sink that is optimal for use (installation) environments where heat dissipation by heat radiation from the heat radiating surface such as the heat radiating side is mainly used and heat dissipation by air convection is hardly expected.

Moreover, since the LED element mounting surface 2 and the heat radiating side surface 3 have an integral structure without a joint surface therebetween, contact thermal resistance that occurs when both of these manufactured separately are joined does not occur. For this reason, the heat conduction between the LED element mounting surface 2 and the heat radiation side surface 3 is easy, and as a result, the heat radiation performance of the entire heat sink is remarkably enhanced.
In addition, the structure of the heat sink 1 is configured such that the LED element mounting surface 2 and the heat radiating side surface 3 are configured by a continuous heat radiating surface facing in any of the three-dimensional X, Y, and Z directions. high. For this reason, even if it is a use which receives a vibration in vehicle-mounted illumination etc., the shape can be maintained without using a special reinforcement member etc., and maintenance-free and lifetime improvement can be achieved. The principle and operational effects of such heat dissipation are basically the same in the following other embodiments.

(FIG. 2, another embodiment of heat sink)
FIG. 2 shows another embodiment of the heat sink for LED lighting according to the present invention. The heat sink 1 for LED illumination shown in FIG. 2 is formed by integrally forming a thin metal plate 1 having a certain plate thickness such as aluminum as in FIG. 1, but the whole as shown in FIG. It has a hollow rectangular tube shape (square tube cup shape). However, the LED lighting heat sink 1 of the present invention shown in FIG. 2 is formed by integrally forming the LED element mounting surface 2 and the four heat dissipating side surfaces 4, 5, 6, and 7 from a single metal thin plate by drawing. This is the same as in FIG.

  As shown in FIG. 2, the heat sink 1 for LED lighting has a shape in which five surfaces of a rectangular parallelepiped are connected, and the LED element mounting surface 2 and four surfaces 4 of the four heat radiation side surfaces forming a plane, The shape has 5, 6, and 7.

  More specifically, in the case of the heat sink 1 for LED illumination of FIG. 2, the LED element mounting surface 2 is a rectangular rectangular plate-shaped top portion, and the four heat radiation side surfaces 4, 5, 6, and 7 are each a square connected to this. It is molded so as to be a square cylindrical body (side). Therefore, the LED element mounting surface 2 and the four heat dissipating side surfaces 4, 5, 6, 7 each have three continuous surface-side surfaces (outside) facing in any of the three-dimensional X, Y, and Z directions. Surface = front surface) 2a, 4a, 5a, 6a, 7a and backside five surfaces (inner surface = back surface) 2b, 4b, 5b, 6b, 7b are formed.

  10 on the bottom side of the cylindrical body is an opening (space part) in which the internal space of the cylindrical body is open toward the outside, where no heat dissipation surface exists. Since the heat sink 1 in FIG. 2 has a rectangular tube shape, for example, when the angle formed by the LED element mounting surface 2 and the four surfaces 4, 5, 6, and 7 of the heat radiating side is 90 degrees, It has the same area as the LED element mounting surface 2. For this reason, it has a comparatively large area with respect to the heat radiation side area of the heat sink 1, and the air in the internal space and the outside air convect inside and outside the heat sink 1 through the opening 10. The structure is sufficient. Here, the relationship between the selection of the angle formed by the LED element mounting surface 2 and the heat radiating side surfaces 4, 5, 6, 7 and the size of the opening 10 and the position of the opening 10 are the same as in FIG.

  In the case of FIG. 2, it has a shape having a flat rectangular LED element mounting surface 2 and four surfaces 4, 5, 6, and 7 of heat radiation side surfaces forming a rectangular tube-shaped rectangular surface. However, since both are formed by drawing from a single aluminum plate as in FIG. 1, the LED element mounting surface 2 and the four heat dissipating side surfaces 4, 5, 6, and 7 are the LED element mounting surfaces. It is continuously continuous with a ridgeline at two ends (corners). In other words, these LED element mounting surface 2 and the front and back surfaces 2a, 4a, 5a, 6a, 7a and 2b, 4b, 5b, 6b, 7b of the four surfaces 4, 5, 6, 7 of the heat radiation side surface are the top LEDs. The LED element L installed on the element mounting surface 2 is continuous with one metal thin plate.

  Here, the LED element mounting surface 2 faces in the Y direction of FIG. 2 as in the case of FIG. 1, and the front surface 2a of the LED element mounting surface 2 is the upward direction of the figure, and the back surface 2b of the LED element mounting surface 2 Is pointing downward in the figure. On the other hand, the four surfaces 4, 5, 6, 7 on the heat radiating side surface are the front and back surfaces 4a, 5a, 6a, 7a and 4b, 5b, 6b, 7b on the four surface 4, 5, 6, 7 on the heat radiating side surface. Are respectively oriented in the X direction and the Z direction (lateral direction). For this reason, the LED element mounting surface 2 and the four heat dissipating side surfaces 4, 5, 6, and 7 together constitute a heat dissipating surface facing in any of the three-dimensional X, Y, and Z directions.

  With the above configuration, the LED illumination heat sink 1 of FIG. In addition, heat is directly conducted from the LED element L to each of the surfaces 2b, 4b, 5b, 6b, and 7b, and the heat is directed to any one of the three-dimensional X, Y, and Z directions toward the heat radiation surfaces. The heat dissipation of each is also possible.

  In the case of the embodiment of FIG. 2, even if the volume is the same as that of the cylindrical cup shape of FIG. For this reason, there is an effect that the projected area onto the heat dissipation space is further increased and the heat dissipation is further improved.

(FIG. 3, another embodiment of heat sink for LED lighting)
FIG. 3 shows another embodiment of the heat sink for LED lighting according to the present invention. A heat sink 1 for LED illumination shown in FIG. 3 is formed by integrally forming a thin metal plate 1 having a certain thickness such as aluminum, as in FIG. (Cylinder cup shape). The heat sink 1 for LED illumination of the present invention shown in FIG. 2 is that the LED element mounting surface 2 and the heat radiating side surface 3 are integrally formed from a single metal thin plate by drawing. Is the same.

  The LED lighting heat sink 1 in FIG. 3 has an LED element mounting surface 2 and four flat heat radiation side surfaces 4, 5, 6, and 7, and is one step higher than the LED element mounting surface 2. It has an L-shaped or step-shaped hollow rectangular parallelepiped or cup shape having a step surface 8 in the Y direction (vertical direction) and a flat top surface 9 that is flat and rectangular.

  More specifically, in the case of the heat sink 1 for LED illumination of FIG. 3, the LED element mounting surface 2 which is a flat rectangular top portion whose top portions are continuous with each other on the step surface 8, and further than the LED element mounting surface 2 It has a flat, rectangular top surface 9 that is one step higher. And the four surfaces 4, 5, 6, and 7 on the heat radiation side are the same rectangular planar shape as in FIG. 2, and the two surfaces 5 and 7 are L-shaped planar shapes unlike FIG. Thus, it is shaped so as to be a rectangular tube (square tube) body (side).

  For this reason, the LED element mounting surface 2, the flat and rectangular top surface 9, the step surface 8 connecting them, and the four heat radiation side surfaces 4, 5, 6, 7 are each three-dimensional X, Y , Z in the continuous direction facing in any direction of Z (outer surface = surface) 2a, 4a, 5a, 6a, 7a, 8a, 9a, and back side 7 surface (inner surface = back surface) 2b Heat radiation surfaces with 4b, 5b, 6b, 7b, 8b, and 9b are formed.

  The flat and rectangular top surface 9 can be used as a place to attach a fixture when fixing a heat sink in LED lighting. Or it can utilize as a place at the time of connecting and fixing other components required for LED illumination, for example, a reflecting plate. Therefore, in the case of FIG. 3, the LED element mounting surface 2 which is a cylindrical top has a two-step staircase shape, but if drawing processing is possible, the LED element mounting surface is necessary. Of course, the number of steps of 2 may be a stepped shape of three or more steps with the stepped surface 8 and a continuous flat rectangular top increased.

  As in FIG. 2, 10 on the bottom side of the cylindrical body is an opening (space part) that is open toward the outside of the internal space of the cylindrical body and does not have a heat radiating side surface. Since the heat sink 1 in FIG. 3 has a rectangular tube shape, for example, when the angle formed by the LED element mounting surface 2 and the four surfaces 4, 5, 6, and 7 of the heat radiating side is 90 degrees, The total area of the LED element mounting surface 2 and the flat and rectangular top surface 9 is the same. For this reason, it has a comparatively large area with respect to the heat radiation side area of the heat sink 1, and the air in the internal space and the outside air convect inside and outside the heat sink 1 through the opening 10. The structure is sufficient. Here, the relationship between the selection of the angle formed by the LED element mounting surface 2 and the heat radiating side surfaces 4, 5, 6, 7 and the size for exhibiting the function of the opening 10 is the same as in the case of FIG. 2.

  In the case of FIG. 3 as well, since both are formed by drawing from a single aluminum plate as in FIG. 2, the LED element mounting surface 2 and the flat and rectangular top surface 9 are connected in the vertical direction. The step surface 8 in the (Y direction) and the four surfaces 4, 5, 6, and 7 that are heat radiation side surfaces are the ridgelines of the LED element mounting surface 2 and the top surface 9 or the end (corner) of the step surface 8. Along with it, it is continuous continuously. In other words, the LED element mounting surface 2, the top surface 9, the step surface 8, and the front and back surfaces 2a, 9a, 8a, 4a, 5a, 6a, 7a, and 2b of the four heat radiation side surfaces 4, 5, 6, and 7 and 2b. , 9b, 8b, 4b, 5b, 6b, 7b are continuous with the LED element L installed on the top LED element mounting surface 2 by a single metal thin plate.

  Here, the LED element mounting surface 2 and the top surface 9 are oriented in the Y direction of FIG. 3, and the surface 2a of the LED element mounting surface 2 and the surface 9a of the top surface 9 are the upward direction of the figure, the LED element mounting surface. The back surface 2b of 2 and the back surface 9b of the top surface 9 face downward in the figure. On the other hand, the four heat radiating side surfaces 4, 5, 6, 7 and the stepped surface 8 are front and back surfaces 4a, 5a, 6a, 7a, 8a and 4b, 5b, 6b, 7b, 8b are respectively X Direction and Z direction (lateral direction). Therefore, the LED element mounting surface 2 and the top surface 9, the heat radiation side surfaces 4, 5, 6, 7 and the step surface 8 are combined to radiate in any of the three-dimensional X, Y, and Z directions. Make up surface.

  With the above configuration, the heat sink 1 for LED illumination of FIG. 3 also has the front surface 2a, back surface 2b, top surface 9a, back surface 9b, and heat radiation side surfaces 4, 5, 6, 7 of the LED element mounting surface 2. Heat is directly conducted from the LED element L to the front and back surfaces 4a, 5a, 6a, 7a and 4b, 5b, 6b, 7b, and the front and back surfaces 8a, 8b of the stepped surface 8, and these heat Heat radiation in any of the three-dimensional X, Y, and Z directions facing each surface is also possible. And compared with the cylindrical cup-shaped or rectangular parallelepiped heat sinks of FIGS. 1 and 2, the projected area to the heat radiation space is further increased by having more surface area such as the top surface 9 even if the volume is the same. The heat dissipation as a heat sink increases.

(FIG. 4, another embodiment of heat sink)
FIG. 4 shows another embodiment of the heat sink for LED lighting according to the present invention. The heat sink 1 for LED illumination shown in FIG. 4 has the same overall shape as FIG. 2, but does not have the heat radiating side surface 6 in FIG. The space has an opening (space portion) 11 that is open to the outside.

  The opening 11 is provided in a range that does not hinder the rigidity of the heat sink 1, and has a larger area sufficient for the heat radiation side area of the heat sink 1 together with the opening 10 on the bottom side. it can. Therefore, the convection function inside and outside the heat sink 1 through the openings 10 and 11 between the air in the internal space and the external air is improved. As a result, although the heat radiation side area is smaller than the case of FIG. 2, the heat radiation side area is reduced, but the air convection function is improved and the heat radiation performance is still excellent.

(Common items of the embodiment)
The above LED element mounting surface and heat radiating side face have a part mounting space, slit, or partial shape depending on the application and mounting location of the heat sink 1, and a process in which these surfaces are cut out to a part of each surface. Alternatively, it may be provided by a molding process that provides unevenness. Furthermore, the heat radiating side surface may have its surface or a part of the surface omitted as shown in FIG.

(Production method of heat sink)
Next, the manufacturing method of the heat sink of the present invention will be described by taking the shape shown in FIG. 1 as an example.

(Material metal sheet)
The metal thin plate, which is a material for drawing (or heat sink), is preferably made of 1000 series pure aluminum as defined in AA to JIS standards in view of the heat conduction characteristics and heat dissipation characteristics required of the heat sink. However, depending on the required properties such as required strength, drawability (formability), corrosion resistance, heat resistance, etc., the same 1000 series or other 3000 series, 5000 series, 6000 series, etc. are suitable aluminum alloys. ya refining conditions Ru is selected.

  The thickness (thickness) of the thin metal plate is selected from the range of 0.4 mm to 2 mm in consideration of the weight reduction of the heat sink, the required strength and rigidity, and the drawability (formability). If this plate thickness is too thin, the required strength and rigidity of the heat sink or drawability (formability) cannot be ensured. On the other hand, if the plate thickness is too thick, the weight reduction of the heat sink is sacrificed, and the drawability (formability) is also lowered.

  When pure aluminum or aluminum alloy is a raw material example, a pure aluminum plate or aluminum alloy plate having a predetermined thickness is manufactured by a normal plate-shaped material manufacturing method such as rolling or extrusion. Next, the manufactured aluminum plate is cut out or punched out into a plate piece having a size capable of forming the outer shape of the heat sink to obtain a flat blank.

(Drawing)
As shown in FIG. 5, the blank 20 is subjected to a drawing process using a press molding apparatus including a punch 22, a die (die) 21, and a plate presser 23 each having a shape corresponding to the shape of the heat sink to be molded. The cylindrical body (hollow cup shape) shape in which the inside becomes a space is molded at room temperature (room temperature). Fig.5 (a) shows the state before the drawing process which set the blank 20 to the press molding apparatus. In FIG. 5B, the punch 20, the die (die) 21, and the plate holder 23 are relatively moved up and down as shown by arrows, and the blank 20 is drawn into the shape of the heat sink 1 shown in FIG. The state during processing is shown. In FIG. 5B, the plate pressing portion 24, which is a surplus portion around the periphery of the heat sink 1 (blank 20), is trimmed during this series of steps.

  Drawing (drawing) by such a press forming apparatus can be applied not only to the heat sink of FIG. 1 but also to the heat sink 1 of FIGS. 2 to 4. It can be easily and inexpensively manufactured by a molding process or a pressing device. This can also be said compared to a heat sink in which a metal flat plate as in Patent Document 4 is manufactured by bending. In addition, since the present invention is a drawing process, there is an advantage that it is easy to ensure dimensional accuracy.

(Surface emissivity of metal sheet)
In order for the heat sink of the present invention to obtain high heat dissipation, the surface emissivity ε of the metal thin plate is preferably 0.6 or more. For this reason, you may give the pre-coating process (coating film) of a black coating material with a high heat dissipation rate before a drawing process to the whole surface of a raw metal thin plate. Alternatively, after the drawing process, after-coating treatment (paint film) of a black paint having a high emissivity may be performed. As a result, the amount of heat transferred by radiation as a heat sink can be increased. This pre-coating process also serves as a lubricant in the drawing process if it is applied to the metal sheet in advance before the drawing process.

  This emissivity ε is a ratio with respect to a theoretical value of thermal radiation of an actual object (a thermal radiation of a black body which is an ideal thermal radiator), and actual measurement is disclosed in Japanese Patent Application Laid-Open No. 2002-234460. The described method may be used, and measurement may be performed by a portable emissivity measuring apparatus developed by the Japan Aerospace Exploration Agency.

The mounting of the heat sink of the present invention to an in-vehicle LED lamp or the like can be performed in the same manner as the mounting of a heat sink that has been widely used so far, and this is also an advantage.
Usually, an in-vehicle LED lamp (vehicle lamp) includes an LED board on which an LED element as a light source is mounted, a reflector that reflects light from the LED forward in the light irradiation direction, and surrounds the LED board and the reflector. And an outer lens made of a transparent material for closing the open front end of the housing, and a heat sink disposed in thermal contact with the LED substrate. The reflector is formed of a resin material and includes a parabolic reflecting surface having a focal point near the LED on the LED substrate. Here, the heat sink of the present invention is used as the LED substrate or a heat sink disposed in thermal contact with the LED substrate.

  According to the vehicle-mounted LED lamp 10 having such a configuration, the LED element is driven to emit light, and the light emitted from the LED element is reflected by the reflector and forwards in the light irradiation direction through the outer lens. Irradiated towards. Here, as described above, the heat generated from the LED is transmitted to the heat sink of the present invention and released to the outside of the housing, and the temperature rise of the LED element is suppressed.

  As described above, the heat sink of the present invention is mainly radiated by radiation of heat from the radiating surface such as the radiating side, and has almost no air convection (almost no heat radiated by air convection can be expected). ) Is the best heat sink. For this reason, in addition to the heat radiating component for vehicle lighting lamps, in addition to the general lighting device, it can be used for a heat radiating component for electronic components and the like.

1: heat sink, 2: LED element mounting surface, 3, 4, 5, 6, 7: heat radiation side surface, 8: step surface, 9: top surface, 10, 11: opening

Claims (2)

A heat sink for in- vehicle LED illumination, in which an LED element mounting surface and a heat dissipation side surface continuous with the LED element mounting surface are integrally and continuously formed on a single aluminum thin plate by drawing, and the LED element mounting surface Is formed into a hollow rectangular tube having an inner space surrounded by these surfaces, and the LED element mounting surface. A heat sink for in- vehicle LED illumination, which has a radiation heat radiation surface continuously facing in any three-dimensional direction by front and back surfaces of the heat radiation side surface and the heat radiation side surface. The onboard LED lighting heat sink of claim 1 the plate thickness of the aluminum sheet is the range of 0.4Mm～2mm.