Heat sink and lighting fixture

Abstract

To obtain a heat sink with a configuration capable of suppressing increase in the maximum value of a tongue ratio when increasing a total surface area.SOLUTION: A heat sink is composed of: a plate-shaped first base 131 having a first surface 1311 and a second surface 1312 that is a back surface parallel to the first surface 1311, and extending in a vertical direction Z; a plurality of plate-shaped heat dissipation fins 134 provided on the first surface 1311 of the first base 131, and extending in the vertical direction Z; a plate-shaped connection part 133 provided on the second surface 1312 of the first base 131, and extending in the vertical direction Z; and a plate-shaped second base 132 having a third surface 1321 that faces the second surface 1312 of the first base 131 and is partially connected to the connection part 133, and extending in the vertical direction Z.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a heat sink for use in a lighting fixture or the like, and to a lighting fixture having a heat sink. [Background technology]

[0002] To prevent the heat generated by the light source of a lighting fixture from affecting other components of the lighting device, conventional lighting devices are provided with a heat dissipation component such as a heat sink that absorbs the heat generated by the light source and dissipates it to the outside. For example, Patent Document 1 discloses a lighting device that includes a substrate on which a light source is mounted and a heat sink located on the back side of the substrate, which is the rear side of the mounting surface. This heat sink has a cylindrical shaft extending vertically from the back side of the substrate and multiple heat dissipation fins protruding laterally from the shaft. A shape like this heat sink, in which the cross section perpendicular to the axial direction of the cylinder has the same cross-sectional shape at any position along the axial direction, can be formed using extrusion molding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-13640 A Summary of the Invention [Problem to be solved by the invention]

[0004] The heat dissipation performance of a heat sink increases with the heat dissipation area, so in order to increase the total surface area of ​​the heat sink in order to improve the heat dissipation performance of a heat sink configured as described above, it is necessary to increase the area of ​​each heat dissipation fin or increase the number of heat dissipation fins. In order to increase the area of ​​each fin in such a heat sink, it is necessary to increase the length and width of the fin, i.e., the axial length of the shaft and the length of the fin protruding from the shaft. If the length of the shaft of the fin is limited, it is necessary to increase the length of the fin protruding from the shaft. Furthermore, if the number of fins in such a heat sink is increased, the gap between adjacent fins will become smaller. On the other hand, when a heat sink having the above-described configuration is extrusion-molded, the difficulty of processing increases as the tongue ratio, which is the ratio of the length of the heat sink protruding from the shaft to the length of the gap between adjacent heat sinks, increases. That is, a large tongue ratio increases the difficulty of processing due to the increased friction between the material and the mold during extrusion molding. The optimum tongue ratio for successful extrusion molding depends on various conditions during extrusion molding, the heat sink material, etc. In a heat sink configured as described above, if the length of the heat dissipation fins protruding from the shaft is increased in order to increase the total surface area, or if the gap between adjacent heat dissipation fins is reduced in order to increase the number of heat dissipation fins, the maximum value of the tongue ratio becomes larger.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to obtain a heat sink configured to prevent the maximum value of the tongue ratio from increasing when the total surface area is increased. [Means for solving the problem]

[0006] The heat sink of the present disclosure comprises a plate-shaped first base extending in a first direction and having a first surface and a second surface which is a back surface parallel to the first surface, a plurality of plate-shaped heat dissipation fins provided on the first surface of the first base and extending in the first direction, a plate-shaped connecting portion provided on the second surface of the first base and extending in the first direction, and a plate-shaped second base extending in the first direction and having a third surface which faces the second surface of the first base and has a third surface which is partially connected to the connecting portion. [Effects of the Invention]

[0007] The heat sink of the present disclosure has a first base having a first surface on which a plurality of heat dissipation fins are provided and a second surface which is an opposite surface parallel to the first surface, and a second base which faces the second surface of the first base and is connected to the first base by a connecting portion.This increases the total surface area by the surface area of ​​the second base, and when the total surface area is increased, it is possible to prevent the maximum value of the tongue ratio between adjacent heat dissipation fins from becoming too high. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a lighting fixture according to a first embodiment, viewed obliquely from below. [Figure 2] FIG. 2 is an exploded perspective view showing a light-emitting unit and a heat sink according to the first embodiment. [Figure 3] 1 is a perspective view of a heat sink according to a first embodiment, viewed obliquely from above. [Figure 4] 1 is a top view of a heat sink according to a first embodiment. FIG. [Figure 5] 1 is a top view of a heat sink arrangement plate and a heat sink according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 The heat sink and lighting fixture according to the first embodiment will be described below with reference to the drawings. In the following drawings, the same reference numerals are used to denote the same or corresponding parts. Furthermore, throughout the specification, directional terms are used as appropriate, but these terms are for explanatory purposes and do not limit the lighting fixture. Terms used to represent directions include, for example, the vertical direction Z, the depth direction X, and the width direction Y. In this embodiment, the first direction is the vertical direction Z, the second direction is the depth direction X, and the third direction is the width direction Y. The vertical direction Z, depth direction X, and width direction Y are perpendicular to each other. The vertical direction Z is the direction of the Z axis shown in FIG. 1 and indicates the up-down direction of the lighting fixture 1. The direction toward the mounting surface such as the ceiling is called the upward direction Z1, and the direction toward the floor is called the downward direction Z2. The depth direction X is the direction of the X axis shown in FIG. 1 and indicates the depth direction of the lighting fixture 1. The width direction Y is the direction of the Y axis shown in FIG. 1 and indicates the width direction of the lighting fixture 1. The plane formed by the depth direction X and the width direction Y is called the plane XY.

[0010] The configuration of lighting fixture 1 according to embodiment 1 will be described with reference to Figs. 1 to 4. Fig. 1 is a perspective view of lighting fixture 1 according to embodiment 1, viewed obliquely from below. Fig. 2 is an exploded perspective view of light-emitting unit 12 and heat sink 13, which will be described later, of lighting fixture 1 in Fig. 1, viewed from above. Fig. 3 is a perspective view of heat sink 13 in Fig. 2, viewed obliquely from above. Fig. 4 is a top view of heat sink 13 in Fig. 2, viewed from above.

[0011] 1, the lighting fixture 1 has a light source unit 10 and a power supply device 100 arranged alongside the light source unit 10 in the depth direction X. The power supply device 100 is electrically connected to the light source unit 10 via a harness 101, and adjusts the power supplied from an external power source and supplies it to the light source unit 10. The light source unit 10 is a unit that emits light in a downward direction Z2 using the power supplied from the power supply device 100. The light source unit 10 includes a light-emitting section 12 that emits light, two heat sinks 13 that dissipate heat generated by the light-emitting section 12 into the atmosphere, and a reflecting section 11 that is formed in a truncated conical cylindrical shape with an opening that exposes the light-emitting section 12 and an opening on the downward Z2 side, and that reflects a portion of the light emitted from the light-emitting section 12 toward the downward Z2 direction. The lighting fixture 1 of embodiment 1 is a fixture that is installed by exposing the light-emitting part 12 and the reflecting part 11 to an opening formed in the mounting part, such as a ceiling (not shown), and embedding it inside the mounting part.

[0012] Figure 2 is an exploded perspective view showing the light-emitting unit 12 and the heat sink 13 in an exploded state. As shown in Figure 2, the light-emitting unit 12 includes a light source unit 121 that emits light using power supplied from the power supply unit 100 and emits light downward, a lens 124 as an optical element that controls the distribution of light emitted from the light source unit 121, a heat dissipation sheet 122 that is provided in contact with the back surface of the light source unit 121, a placement plate 123 that is provided in contact with the heat dissipation sheet 122 and to which the light source unit 121 is fixed, and a housing 125 that is fastened to the placement plate 123 with screws or the like and that houses the light source unit 121, the lens 124, and the heat dissipation sheet 122.

[0013] The light source section 121 has a light emitting element such as an LED (Light Emitting Diode).

[0014] The heat dissipation sheet 122 is a sheet-like member made of a material with high thermal conductivity, and is disposed between the light source unit 121 and the arrangement plate 123. The heat dissipation sheet 122 facilitates the transfer of heat generated by the light source unit 121 as the light source unit 121 emits light to the arrangement plate 123. That is, the heat dissipation sheet 122 comes into close contact with the light source unit 121 and the arrangement plate 123, thereby lowering the thermal resistance compared to air, etc., and facilitating the transfer of heat from the light source unit 121 to the arrangement plate 123.

[0015] The arrangement plate 123 is a disk-shaped member, and the light source unit 121 is attached to the underside, which is one surface of the arrangement plate 123, via a heat dissipation sheet 122 using a fixing member such as a screw, and two heat sinks 13 are attached to the upper surface, which is the other surface opposite to the one surface. The arrangement plate 123 dissipates heat from the light source unit 121 transmitted via the heat dissipation sheet 122 into the atmosphere and also transfers the heat to the heat sinks 13, and is preferably made of a metal with high thermal conductivity such as an aluminum alloy.

[0016] The housing 125 has an opening that exposes the lens 124, and houses the light source unit 121, the heat dissipation sheet 122, and the lens 124 while covering them from below. The housing 125 is attached to the mounting plate 123 using fixing members such as screws.

[0017] 3 is a perspective view of the heat sink 13 as viewed obliquely from above, and FIG. 4 is a top view of the heat sink 13 as viewed from above. As shown in FIGS. 3 and 4, the heat sink 13 has a first surface 1311 facing another heat sink 13 arranged in the width direction Y and a second surface 1312 that is a back surface parallel to the first surface 1311, and includes a plate-like first base 131 extending in the up-down direction Z, which is a first direction, and a plurality of plate-like members that are provided on the first surface 1311 so as to protrude in the width direction Y from the first surface 1311 of the first base 131 and extend in the up-down direction Z similarly to the first base 131. The first base 131 includes a plate-shaped heat dissipation fin 134, a plate-shaped connecting portion 133 that is provided on the second surface 1312 of the first base 131 so as to protrude from the second surface 1312 in the width direction Y and extends in the vertical direction Z, and a plate-shaped second base 132 that has a third surface 1321 that faces the second surface 1312 of the first base 131 and connects to the connecting portion 133, and a fourth surface 1322 that is a back surface parallel to the third surface 1321 and is formed in a flat shape, and that extends in the vertical direction Z. The first base 131 has a flat first side surface 1313 formed at an end in the depth direction X, and the second base 132 has a second side surface 1323 formed at an end in the depth direction X.

[0018] The heat sink 13 having such a configuration can be integrally formed by extrusion molding with the vertical direction Z as the extrusion direction, with the first base 131, second base 132, connecting portion 133, and heat dissipation fins 134 formed by this extrusion molding extending in the vertical direction Z.

[0019] Here, the two heat sinks 13 are attached to the upper surface of the arrangement plate 123 with the fourth surfaces 1322 of the second bases 132 spaced apart and facing each other. Since the two heat sinks 13 are spaced apart, heat can be dissipated from the fourth surfaces 1322 of the second bases 132 to the atmosphere. Furthermore, since the second base 132 of the heat sink 13 has a flattened fourth surface 1322, the heat sink 13 extruded from the mold by extrusion molding using the extrusion molding device is stably placed on the mounting table of the extrusion molding device, thereby preventing the extruded heat sink 13 from changing its position or rolling over and becoming damaged.

[0020] As shown in FIG. 4, the connecting portion 133 is provided on a portion of the second surface 1312 of the first base 131 and connects a portion of the second surface 1312 of the first base 131 to a portion of the third surface 1321 of the second base 132. Here, as shown in FIG. 4, the ratio of the length A in the depth direction X from the connecting portion 133 to the first side surface 1313 of the first base 131 divided by the length B in the width direction Y between the second surface 1312 of the first base 131 and the third surface 1321 of the second base 132 is called the base tongue ratio. When the heat sink 13 is molded by extrusion molding, the higher the base tongue ratio, the greater the frictional resistance between the material and the mold, making processing more difficult. The optimum value for the base tongue ratio is determined depending on various conditions during extrusion molding, the material of the heat sink 13, etc. Therefore, in the first embodiment, the maximum value of the tongue ratio that is allowable in manufacturing is called the optimum value of the tongue ratio of the base, and the optimum value of the tongue ratio of the base is not limited to a specific value.

[0021] As shown in FIG. 4 , the heat dissipation fins 134 are fins that protrude in the width direction Y from the first surface 1311 of the first base 131. The fins include a first heat dissipation fin 1341 located at the center of the first surface 1311 of the first base 131 and multiple second heat dissipation fins 1342 located adjacent to the first heat dissipation fin 1341 in the depth direction X. As shown in FIG. 4 , the ratio of the length C of the heat dissipation fin 134 from the first surface 1311 to its tip to the distance D between adjacent heat dissipation fins 134 is called the tongue ratio of the heat dissipation fin 134. When the heat sink 13 is molded by extrusion molding, the higher the tongue ratio of the heat dissipation fin 134, the greater the frictional resistance between the material and the mold, making processing more difficult. The optimum tongue ratio of the heat dissipation fin 134 depends on various conditions during extrusion molding, the material of the heat sink 13, and other factors. Therefore, in the first embodiment, the maximum value of the tongue ratio allowed in manufacturing is called the optimum value of the tongue ratio of the heat dissipation fins 134, and the optimum value of the tongue ratio of the heat dissipation fins 134 is not limited to a specific value.

[0022] 5 is a top view of the arrangement plate 123 and one heat sink 13 combined together, and as shown in Fig. 5, the first heat dissipation fin 1341 arranged in the center of the first surface 1311 is formed to a length such that its tip in the width direction Y protrudes to the vicinity of the outer edge of the arrangement plate 123. Increasing the length of the first heat dissipation fin 1341 in this way makes it possible to increase the heat dissipation area. The first heat dissipation fin 1341 is formed to have a thickness in the depth direction X that is thicker than the second heat dissipation fin 1342.

[0023] 5, the plurality of second heat dissipation fins 1342 arranged adjacent to the first heat dissipation fin 1341 in the depth direction X are formed to have a length such that the tip of each in the width direction Y protrudes to the vicinity of the outer edge of the arrangement plate 123. Increasing the length of each of the plurality of second heat dissipation fins 1342 in this way makes it possible to increase the heat dissipation area. 5, when the arrangement plate 123 is formed in a disk shape, the multiple second heat dissipation fins 1342 are formed so that their lengths in the width direction Y become shorter as they are arranged from the center to the end in the depth direction X of the first base 131. In this way, when heat dissipation fins 134 with long lengths in the width direction Y and heat dissipation fins 134 with short lengths are mixed, even if the spacing between the short heat dissipation fins 134 and the adjacent heat dissipation fins 134 is made shorter than the spacing between the long heat dissipation fins 134 and the adjacent heat dissipation fins 134, the tongue ratio of the short heat dissipation fins 134 can be made the same as the tongue ratio of the long heat dissipation fins 134. In other words, when the lengths of the heat dissipation fins 134 and the spacing between the heat dissipation fins 134 are set so that the tongue ratio is within an upper limit value, such as a predetermined optimum value, for all of the first bases 131, the shorter the length of the heat dissipation fins 134, the shorter the spacing between adjacent heat dissipation fins 134 can be. By shortening the intervals between the heat dissipation fins 134, it is possible to increase the number of heat dissipation fins 134 provided on the first base 131. In the example of Fig. 5, the second heat dissipation fin 1342 is arranged so that the interval between the first heat dissipation fin 1341 or the second heat dissipation fin 1342 arranged adjacent to it in the depth direction X becomes shorter as the second heat dissipation fin 1342 is formed to have a shorter length in the width direction Y.

[0024] Next, we will explain the operation of the lighting fixture 1 configured as described above and the function of the heat sink 13 provided in the lighting fixture 1. When the power supply device 100 adjusts the power supplied from the external power source and supplies it to the light source unit 10, the light-emitting section 12 of the light source unit 10 emits light and emits light in the downward direction Z2. At this time, heat generated in the light-emitting section 12 is transferred to the two heat sinks 13 via the heat dissipation sheet 122 and the arrangement plate 123 on the back surface of the light source section 121, and is then dissipated from the heat sinks 13 to the atmosphere. Here, the relationship between the shape of the heat sink 13 and the heat dissipation performance will be described. The heat dissipation performance of the heat sink 13 increases as the total surface area of ​​the heat sink 13 that is in contact with the air increases. Note that the surface of the heat sink 13 that is in contact with the placement plate 123 does not come into contact with the air, and therefore does not dissipate heat. Hereinafter, the total surface area is referred to as the total surface area of ​​the heat sink 13, excluding the surface that is in contact with the placement plate 123. In general, lighting fixture 1 needs to be designed to fit within a predetermined size, taking into consideration factors such as the installation location. Heat sink 13 according to embodiment 1 is designed such that its length in the depth direction X, width direction Y, and up-down direction Z is limited, and its outline projected onto plane XY is generally contained within the outer edge of arrangement plate 123, which is generally disk-shaped. Under these constraints, heat sink 13 is designed such that the surfaces of first base 131 and the plurality of heat dissipation fins 134 provided on first base 131 contribute to an increase in the total surface area, and second base 132, which is connected to and faces second surface 1312 of first base 131, also contributes to an increase in the total surface area. In a heat sink 13 having this shape, compared to a heat sink formed only with a first base 131 and heat dissipation fins 134, the surface area of ​​each heat dissipation fin 134 is reduced because each heat dissipation fin 134 is shorter by the length of the connecting portion 133, but the total surface area can be increased by adding the surface area of ​​the connecting portion 133 and the second base 132. Furthermore, the shortening of the length of the heat dissipation fins 134 as a result of providing the second base 132 as described above acts to reduce the tongue ratio of each heat dissipation fin 134. Therefore, when there is a constraint that the tongue ratio must be kept within an appropriate value, this heat sink 13 can shorten the spacing between each heat dissipation fin 134 compared to when it is formed only with the first base 131 and the heat dissipation fins 134, and as a result, the total surface area can be increased by increasing the number of heat dissipation fins 134 on the first base 131.

[0025] As described above, the heat sink 13 has a plate-shaped first base 131 extending in the vertical direction Z and having a first surface 1311 and a second surface 1312 which is the back surface parallel to the first surface 1311, a plurality of plate-shaped heat dissipation fins 134 provided on the first surface 1311 of the first base 131 and extending in the vertical direction Z, a plate-shaped connecting portion 133 provided on the second surface 1312 of the first base 131 and extending in the vertical direction Z, and a plate-shaped second base 132 extending in the vertical direction Z and having a third surface 1321 which faces the second surface 1312 of the first base 131 and has a portion which connects to the connecting portion 133. Therefore, compared to a heat sink formed only with the first base 131 and the heat dissipation fins 134, the total surface area of ​​the heat sink 13 is increased by adding the surface area of ​​the connecting portion 133 and the second base 132, and by shortening the length of the heat dissipation fins 134, the maximum value of the tongue ratio between adjacent heat dissipation fins 134 can be prevented from becoming too high.

[0026] Furthermore, since the heat sink 13 of embodiment 1 has a configuration having the connecting portion 133 and the second base 132 as described above, the length of the heat dissipation fins 134 is shorter than that of a heat sink formed only with the first base 131 and the heat dissipation fins 134, and the numerator of the tongs ratio is smaller.Therefore, when there is a constraint that the tongs ratio must be kept within an appropriate value, the spacing between the heat dissipation fins 134, which is the denominator of the tongs ratio, can be shortened, and the total surface area can be increased by increasing the number of heat dissipation fins 134 on the first base 131. That is, the adjacently arranged heat dissipation fins 134 are spaced apart at intervals corresponding to the length from the first surface 1311 to the tip of each heat dissipation fin 134. This correspondence means that the length of each heat dissipation fin 134 and the intervals between the heat dissipation fins 134 are determined so that the tongue ratio falls within an appropriate value. Furthermore, within the range in which this correspondence is maintained, the intervals between adjacently arranged heat dissipation fins 134 can be shortened as the length of each heat dissipation fin 134 becomes shorter, thereby allowing the number of heat dissipation fins 134 to be increased.

[0027] Furthermore, since the heat sink 13 of the first embodiment is attached to the disk-shaped arrangement plate 123 and the tips of the heat dissipation fins 134 are formed to a length that protrudes to the vicinity of the outer edge of the arrangement plate 123, the lengths of the plurality of heat dissipation fins 134 can be made longer as they are closer to the center in the depth direction X of the first base 131. Therefore, by shortening the intervals between the heat dissipation fins 134 and arranging the plurality of heat dissipation fins 134 as close to the center as possible, the length of each heat dissipation fin 134 can be made longer, and the total surface area can be increased.

[0028] In the first embodiment, the two heat sinks 13 are described as being attached to the upper surface of the arrangement plate 123 with the fourth surfaces 1322 of the second bases 132 facing each other at a distance, but the heat sinks 13 may also be attached to the upper surface of the arrangement plate 123 with the fourth surfaces 1322 of the second bases 132 abutting against each other. The heat sink 13 is prevented from dissipating heat into the atmosphere by the fourth surfaces 1322 of the second bases 132, but the position of the second bases 132 is closer to the light-emitting unit 12 on the arrangement plate 123, making it easier for heat to be transferred from the light-emitting unit 12 to the second bases 132. Furthermore, the number of heat sinks 13 attached to the upper surface of the arrangement plate 123 is not limited to two, and three or more may be attached.

[0029] Furthermore, in embodiment 1, it was explained that the heat sink 13 extruded from a mold by extrusion molding using an extrusion molding device can be stably placed on the mounting table of the extrusion molding device due to the presence of a flattened fourth surface 1322 on the second base 132 of the heat sink 13. However, as shown in FIG. 4, the first side surface 1313 of the first base 131 and the second side surface 1323 of the second base 132 can be formed to overlap the same imaginary plane P, and during extrusion molding using the extrusion molding device, these first side surface 1313 and second side surface 1323 can be placed on the mounting table of the extrusion molding device, so that the extruded heat sink 13 can be stably placed on the mounting table.

[0030] In the first embodiment, the light source unit 121 is described as having a light-emitting element such as an LED, but the light-emitting element may be any element that emits light when supplied with power, such as a laser element or an organic EL (Electro Luminescence).

[0031] Furthermore, in the first embodiment, the arrangement plate 123 is described as being disk-shaped, but the arrangement plate 123 is not limited to being disk-shaped, and may be elliptical, rectangular, or polygonal.

[0032] Furthermore, in the first embodiment, the means for attaching the heat sink 13 to the arrangement plate 123 is screwed, but this is not limited to screws, and the attachment may be performed using fixing members such as welding or rivets. [Explanation of symbols]

[0033] 1 lighting fixture, 10 light source unit, 11 reflecting portion, 12 light emitting portion, 121 light source portion, 122 heat dissipation sheet, 123 arrangement plate, 124 lens, 125 housing, 13 heat sink, 131 first base, 1311 first surface, 1312 second surface, 1313 first side surface, 132 second base, 1321 third surface, 1322 fourth surface, 1323 second side surface, 133 connecting portion, 134 heat dissipation fin, 1341 first heat dissipation fin, 1342 second heat dissipation fin, 100 power supply unit, 101 harness.

Claims

1. a plate-shaped first base having a first surface and a second surface that is a back surface parallel to the first surface and extending in a first direction; a plurality of plate-shaped heat dissipation fins provided on the first surface of the first base and extending in the first direction; a plate-shaped connecting portion provided on the second surface of the first base and extending in the first direction; a plate-shaped second base extending in the first direction and having a third surface that faces the second surface of the first base and a portion of which is connected to the connecting portion; A heat sink equipped with

2. The heat sink according to claim 1 , wherein the plurality of heat dissipation fins are arranged adjacent to each other on the first surface of the first base.

3. 3. The heat sink according to claim 2, wherein the adjacently arranged heat dissipation fins are arranged at intervals corresponding to the length from the first surface to the tip of each heat dissipation fin.

4. A light-emitting portion; a circular arrangement plate having one side surface on which the light emitting unit is attached and another side surface opposite to the one side surface; The heat sink according to claim 1 , attached to the other surface of the arrangement plate; A lighting fixture equipped with

5. The lighting fixture according to claim 4 , wherein the heat dissipation fins of the heat sink are formed to a length such that their tips protrude from the first surface of the first base to an outer edge of the arrangement plate.

6. two heat sinks are attached to the other surface of the arrangement plate; The lighting fixture of claim 4, wherein the two heat sinks are attached to the mounting plate with their fourth surfaces, which are back surfaces parallel to the third surface of the second base, facing each other at a distance.

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