ITPI20100029A1 - METHOD FOR THE MANUFACTURE OF A FINNED BODY OF SUPPORT FOR POWER LED - Google Patents

Description

â € œMETHOD FOR MANUFACTURING A FINNED SUPPORT BODY FOR POWER LEDâ €,

DESCRIPTION

Scope of the invention

The present invention relates to the lighting sector, and more precisely it refers to a method for making a finned heat sink of a lighting device with power LEDs.

Furthermore, the invention refers to a lighting fixture with power LEDs with a high efficiency cooling system.

Description of the prior art

As is well known, thanks to the development of LED technology, lighting elements of ever greater efficiency are available. In fact, there are elements that use power LEDs, which are made with microelectronic technologies, dense side by side with very numerous arrays of single LEDs. A power LED can have a power of a few watts, normally from 1 Watt up to several tens of Watts, and is able to obtain a very high efficiency, for example with a luminous flux of over 100 lumen / watt.

One of the technological limitations of luminaires that use such lighting elements is cooling. In fact, as the temperature increases, the electronic components that are part of these lighting elements reduce their performance, and if not completely controlled in temperature they can "burn out" in a very short time.

It is therefore advisable that the power LED lighting element does not exceed a certain limit temperature, recommended by the manufacturer. Therefore, it is necessary to mount these elements on a support that absorbs a lot of heat and at the same time is able to disperse all the absorbed heat, keeping below this limit temperature.

In known LED lighting fixtures, cooling is obtained by means of finned radiator elements which, if exposed to the air of the external environment, ensure the dispersion of the heat adequately generated by a single power LED.

However, if you want to mount more power LEDs on the same support, in order to achieve a greater luminous flux, the problem arises of how to disperse all the heat.

For example, a projector on which one or more power LEDs are mounted, to reach higher powers cannot be made with current techniques without using a forced circulation of air against the finned radiator elements.

However, the forced circulation, obtained by means of fans, has the following drawbacks. In the first place, the use of a fan involves a certain energy consumption, penalizing one of the main advantages of high-power LED lighting fixtures, that is, their reduced energy consumption. Furthermore, the use of a fan affects the design of high-power LED lighting fixtures, limiting the designersâ € ™ creativity. In addition, the mechanical parts of the fan can deteriorate over time, compromising its efficiency and generating annoying noises.

An example of a lighting fixture that adopts a fan for cooling the power LED light sources is described in US20090323361. In this case, fins are provided to increase the efficiency of the heat exchange between the air flow generated by the fan and the components to be cooled.

EP2072893, on the other hand, describes a high-power LED lighting fixture without a fan. In this case, the cooling action is carried out exclusively by finned radiator elements which provide a series of heat exchange surfaces that extend radially starting from a cylindrical body.

Normally, a finned radiator element is produced by molding starting from materials with high thermal capacity. However, to disperse heat in a natural way, ie without the use of fan elements, very bulky finned surfaces are required.

Furthermore, to prevent the finned radiator elements from being exposed, containment casings of better aesthetic appeal can be used. This, however, can generally worsen the heat exchange at the expense of the life of the power LED.

Summary of the invention

It is therefore an object of the present invention to provide a finned support body for power LEDs which has a high heat dissipation efficiency and reduced overall dimensions.

It is also an object of the present invention to provide a lighting fixture which has such a finned support body for a power LED.

It is also an object of the present invention to provide a lighting device which allows a good heat exchange by using such a finned body inside a containment casing.

Another object of the present invention is to provide a method for manufacturing a finned support body for power LEDs which is simple to manufacture and economically advantageous.

These and other purposes are achieved by a finned body for a power LED lighting fixture comprising:

- a monoblock in heat conducting material, called monoblock having a front portion with a front seat for applying a power LED and a rear finned portion, in which said rear finned portion comprises:

- starting from a determined distance D from said front seat, a first flat notch ending in correspondence with a solid root with circular section of a determined diameter Φ, forming between said first notch and said frontal seat a support base of thickness D;

- starting from a determined distance D1 greater than D from said front seat, a second flat notch that ends in correspondence with a solid root of said material with a specific diameter section Φ1, forming between said first and second notch a first fin A1;

- starting from a determined distance D2 greater than D1 from said front seat, a third flat notch that ends in correspondence with a solid root of said material with a specific diameter section Φ2, forming between said second and third notch a second fin A2;

- further flat notches which together with said first, second, third notch form said rear finned portion, forming a respective fin Ai between two consecutive notches, each fin Ai of said rear finned portion being at a distance from a previous fin, and each fin extending from a circular root filled with said material with a section having a diameter Φi.

In particular, the distances are constant, while the diameters Φi are decreasing. In this way, the solid root from which the fins extend has a conical shape with a vertex converging towards a last fin An which is in the most distal position from the front seat of the block where the power LED is applied.

The conical shape of the root of the fins Ai with a decreasing trend optimizes the cooling phase, as the flow of heat and temperature has a substantially decreasing trend starting from the front seat where the power LED is applied towards the last fin. In this case, the maximum section of the root is located in correspondence with the hottest area, which is the central part of the support base, which acts as a heat accumulator, right next to the application site of a power LED, where the greatest flow of heat to be disposed of is concentrated.

Alternatively, the distances d and the diameters Φi are constant. In this case, the heat flow more easily reaches the fins more distal than the application site of a power LED.

Advantageously, all the fins Ai have a constant radius.

Alternatively, a first group of fins with radius r1 and a second group of fins with radius r2 greater than r1 are provided, starting from said front seat towards said last fin. In this way, by making fins with variable dimensions, the overall space on the front part of the finned body is reduced, facilitating recessed installation and maximizing the heat exchange surface. Preferably, said finned body comprises an externally threaded front attachment portion in correspondence with said support base designed to allow the coupling of the finned body with a support sleeve, adapted to support a reflector body and to allow recess, to example in countertops, walls, etc.

Advantageously, said threaded front attachment portion is treated with a thermal conductive paste, for example based on silver.

In particular, on said front seat there are obtained first through holes which pass through said finned body starting from said front seat towards said last fin, said first holes being suitable for receiving power supply cables of the power LED.

Advantageously, second through holes are obtained on said front seat, in particular arranged more externally than said first through holes which pass through said finned body starting from said front seat towards said last fin, said second holes being able to allow an axial flow of € ™ air and favor heat exchange, particularly in the case of a finned body enclosed in an external casing.

In particular, said finned body is anodized aluminum, preferably black anodized aluminum, achieving excellent thermal conductivity even on the surface, increasing the efficiency and duration of the power LED. For example, an aluminum alloy 6060, 6026 or 6082 with magnesium and silicon can be used, having excellent machinability characteristics for machine tools.

According to another aspect of the invention, a lighting device with power LEDs is characterized in that it comprises a finned body made according to the preceding claims, on said finned body being mounted, in correspondence with said front seat, said power LED , and a reflector body.

Advantageously, an external tubular casing is connected to said finned body having a bottom in which passage openings are obtained. In this way, the openings allow the power cables to pass through and favor the circulation and exchange of air inside the tubular casing by fresh air that laps the finned body.

In particular, said external tubular casing is fixed to said finned body by means of an annular ring nut having a plurality of axial holes which engage on said support base. In this way, the passage of air is allowed from a front space, which surrounds said reflector body, towards a rear space, which surrounds said finned body.

In particular, a perforated annular mask is provided between said tubular casing and said reflector body which allows the passage of air between the outside of said tubular casing and said front space. In particular, a flow of fresh air enters through the perforated mask into the front space surrounding the reflector body, passes through the holes of said annular ring nut, passes into said rear space that surrounds the finned body, touching said fins, and also passes through the holes in the finned body, regulating the temperature, and exits towards the outside through the passage openings obtained on the bottom of the tubular body.

In particular, the annular ring nut and the tubular body are made of heat conducting material, so that there is a flow of heat by conduction from said finned body to said tubular body, whose large external surface forms an ideal heat exchange surface. to adjust the temperature of the finned body and therefore of the power LED.

In a particular embodiment, a lighting device with power LEDs is characterized in that it comprises a plurality of finned bodies made according to the previous claims and mounted on a plate made of heat-conducting material so as to all protrude from a first face of said plate, and in such a way that each front seat of said finned bodies protrudes from a second face of said plate opposite to said first face, on each finned body being mounted, at said front seat, a respective power LED and a reflector body.

In this way, it is possible to realize a luminaire having any number of power LEDs. In particular, said plate acts as a support for an array of elementary lighting devices. By placing said plate with the first face upwards, the array of elementary lighting fixtures is automatically cooled whatever the lighting power of the fixture. For example, the plate can be suspended at the desired height with the second face facing down. The number of elementary luminaires in the array can be chosen according to the required luminance.

In a floor lamp type embodiment, the plate can have the first face facing downwards, and the second face facing upwards, to illuminate upwards, and a plurality of holes through the plate for the passage of hot air upwards through the plate.

According to a further aspect of the invention, an LED light spotlight is characterized in that it comprises a finned body made according to the preceding claims.

According to another aspect of the invention, the above purposes are also achieved by a method for manufacturing a finned body comprising the steps of:

â € “prepare a monobloc in heat-conducting material;

â € “create a seat for the application of a power LED on a front seat of said monobloc;

- bring said monobloc into rotation;

- make a first plane notch on said monoblock, with a cutting tool having a thickness of less than 3mm, starting from a certain distance D from said front seat, until leaving a solid root with a circular section of a determined diameter Φ ;

- move said cutting tool by a distance d1 greater than D from said front seat and make a second flat notch until leaving a circular root filled with said material with a section having a determined diameter Φ1;

- move said cutting tool by a distance d2 greater than d1 from said front seat and make a second flat notch until leaving a circular root filled with said material with a section of determined diameter Φ2;

- repeat this operation until a single finned body is obtained, in which each fin Ai is a distance from the previous fin, and each fin extends from a circular root filled with said material with a diameter Φi, called finned body ending with a last fin An.

Brief description of the drawings

The invention will be illustrated below with the following description of an embodiment thereof, given by way of non-limiting example, with reference to the attached drawings in which:

- figure 1 shows a sectional view of a finned body, according to the invention;

- figures 2 to 6 schematically show a method for producing the finned body of figure 1, for supporting a power LED, according to the invention;

Figure 7 is a perspective view of a lighting apparatus comprising the finned body of Figure 1;

- figure 8 shows a schematic front view of the lighting fixture in a seat of application of the power LED;

figure 9 shows a schematic view of the application seat of the power LED;

- figure 10 shows a lighting fixture equipped with a tubular casing which contains the finned body, according to the invention;

- figure 11 shows a sectional view of the lighting apparatus of figure 10 which highlights the flow of air that passes through it, suitable for regulating the temperature of the finned body and therefore of the power LED;

Figures 12 and 13 show a perspective view of a composite lighting apparatus formed by a plurality of lighting apparatus;

- figure 14 shows the composite lighting fixture of figures 12 and 13 used as a floor lamp.

Detailed description of some embodiments With reference to Figure 1, a finned body 100 has a plurality of fins Ai at a distance from each other, and each fin Ai extends from a solid root of material 3 with a circular section with a diameter Φi .

The root 3 extends from a support base 1 having a support seat or front seat 2, obtained on a front face 1a, for a power LED 20, shown below.

In the case of figure 6, the distances are constant, while the diameters Φi are decreasing. In this way, the root 3 from which the fins Ai extend has a conical shape with a vertex converging towards a last fin An, opposite to the front seat 2 of the block where the power LED 20 is applied.

The conical shape of the root 3 of the fins Ai with decreasing trend optimizes the cooling phase, as the heat generated by the power LED 20 accumulates in the central part of the support base 1 and is rapidly dissipated towards the fins Ai through the large section of the conical root 3. The conical shape allows the heat flow to reach all the fins starting from the support base 1, on whose support seat 2 the power LED 20 is applied, towards the last fin An.

In a way not shown, the diameters Φi are constant. In this case the root is cylindrical, and allows a high flow of heat towards the more distal fins, close to the last fin An, which are therefore able to dispose of more heat.

Each fin Ai can have a constant radius, or, as shown in Figure 6, a first proximal group of fins with radius r1 and a second distal group of fins with radius r2 greater than r1 is provided. Or, in a way not shown, the fins have an increasing diameter starting from the front seat 2 towards the last fin An. In this way, by making fins with variable dimensions, the overall space on the front part of the finned body is reduced, facilitating recessed installation or in protective casings, maximizing the heat exchange surface.

The finned body 100 has the support base 1 which comprises a threaded attachment portion 5, for connection with other constituent parts of the lamp shown further on. Furthermore, it has a first series of through holes 8a, for the passage of wires, and a second series of through holes 8b, for ventilation. The holes 8a, 8b can be made as shown in figure 8, of which figure 1 represents a cross section according to the arrows I-I. Figure 8 shows further holes 8c, for fixing the power LED 20 by means of screws (e.g. fig.8B, screws 63).

As shown schematically in Figures 2 to 6, a method for manufacturing the finned body 100 is described. In particular, the method comprises the steps of preparing a raw block 10 for example as the end portion of a bar made of heat conducting material. . In particular, the bar is made of anodized aluminum, in particular black anodized aluminum, achieving excellent thermal conductivity even on the surface, increasing the efficiency and duration of the power LED. For example, an aluminum alloy 6060, 6026 or 6082 with magnesium and silicon can be used, having excellent machinability characteristics for machine tools.

Initially, the support seat 2 for a power LED 20 is made on the front face 1a of the block 10. The machining involves the use of cutting tools 40, to flatten and machine the front seat 2 as well as a surface rolling external 5, 6 and 7. The front seat 2 can include a protruding border of reference 4. In particular, the various processes are carried out by means of a numerically controlled lathe.

Subsequently, as shown in the section of figure 3, longitudinal through holes 8a and 8b are made on the monobloc 10 by means of a drilling tool 41 starting from the front seat 2. For example, a drilling step can be carried out by means of multiple drilling tools.

Finning A1, A2, A3, â € ¦ An, Ai are then made on the monoblock 10 mounted on a lathe (Fig. 4) with a cutting tool 42, having a cutting width of less than 3mm, for example 2mm, starting from a determined distance D from the front seat 2, so as to form the support base 1 of thickness D. The first flat notch F1 is made by the cutting tool 42 until leaving a solid root with a circular section of a determined diameter Î ¦.

The tool 42 is then made to advance (Fig. 5) by a distance d1 from the front seat 2 greater than D, to make a second flat notch F2 until leaving a root full of material with a circular section of a determined diameter Φ1 (Fig. 4). The first fin A1 is created between the two notches F1 and F2.

In the same way (Fig. 6), by moving the cutting tool 42 by a distance d2 greater than d1 from the front seat 2, a third plane notch F3 is made until leaving a full circular root of the material with a section of a determined diameter Φ2 and the second fin A2.

By repeating these operations, the finned body 100 is obtained, shown in Figure 1, in which each fin Ai is at a distance of from the previous fin, and each fin Ai extends from a solid root of material with a circular section with a diameter Φi. In this way, the root from which the fins extend has a conical shape with a vertex converging towards the last fin An.

As described above, the threaded front attachment portion 5 (Fig. 1) serves to connect parts of a lighting fixture which uses the finned body 100 as a thermal regulating element of a power LED 20.

For example, Fig. 7 shows a recessed spotlight obtained by fixing to the finned body 100 a sleeve or socket 140 with stop flange 130. The assembly of the sleeve 140 can be achieved by adding a thermal conducting paste on the threaded front attachment portion 5 of Fig. 1, for example based on silver or any other suitable commercial product. In this way, the sleeve 140, made of thermal conductive material, also contributes to the cooling of the finned body 100.

Figure 7 shows how inside the flanged sleeve 140 a reflector 110 is arranged, closed by a protective glass or lens not shown. In the center of the reflector there is the power LED 20, mounted for example on an aluminum plate 21. The electrical connection is made possible by the electric cables 61, which reach the power LED 20 through the holes 8a.

The power LED 20 used can be with an external power supply, or in the form of an integrated circuit, for example a multi-core LED with a printed integrated circuit.

A remote power supply in wireless communication with the LED light source is also possible. The plate 21 and the chip 20 are better visible in Fig. 9, where the soldering points 62 of the cables 61 emerging from the holes 8a are visible, in correspondence with the angular notches 64 of the plate 21. The mounting screws 63 are also visible. , through the blind holes 8c (Fig. 8) to the seat 2 of the finned body 100.

With reference to figures 10 and 11, a different power LED lighting device has a finned body 100 (Fig. 11) to which, instead of a flanged sleeve, a cylindrical sleeve 140â € ™ can be connected, on the continuation of which is connected an external tubular casing 120 having a bottom 121 in which passage openings are obtained, for example made by means of a grid 180. In this way, the openings allow the power cables to pass and favor the circulation and exchange of air to the Inside of the tubular casing 120.

In particular, the tubular casing 120, or the sleeve 140â € ™, or a single tubular body not shown, is fixed to the finned body by means of an annular ring nut 145 having a plurality of axial holes 146 which engages on the support base 1. In this way, the passage of air is allowed from a front space 150, which surrounds the reflector body 110, to a rear space 170, which surrounds the finned body 100.

In particular, between the tubular sleeve 140â € ™ and the reflector body 110, fixed to the tubular sleeve 140â € ™ by a clamping ring 132, there is a perforated annular mask 130 which allows the passage of air 160 through holes 131 between the outside of the tubular casing and the front space 150. In particular, a flow of fresh air enters the front space 150 that surrounds the reflector body 110 through the perforated mask 130, passes through the holes 146 of the annular ring 145 , passes into the rear space 170 that surrounds the finned body 100, touching the fins Ai, and also passes through the holes 8b of the finned body, regulating the temperature, and exits towards the outside through the passage openings obtained on the grilled bottom 180 of the tubular body 120.

In particular, the annular ring 145 and the tubular body 120.140â € ™ are made of heat-conducting material, so that through it there is a flow of heat by conduction from the finned body 100 to the tubular body 120.140â € ™, whose large external surface forms an ideal heat exchange surface to regulate the temperature of the finned body 100 and therefore of the power LED 20.

Figure 11 also shows a protective glass 191, which can also be a lens, and a space 190 for the projection of the light generated by the LED 20. Furthermore, Figure 10 shows an attachment 122 for a support, not shown, of the € ™ lighting fixture.

In a further embodiment, shown in figures 12, 13 and 14, a lighting apparatus 200 with power LEDs is characterized in that it comprises a plurality of finned bodies 100 (Fig. 13) made in the manner described above, and mounted on a plate 201 made of heat-conducting material so as to all protrude from a first face 202 of the plate, and so that each front seat 2 of the finned bodies protrudes from a second face 203 of the plate 201 (Fig. 12) opposite to the first face 201. A respective power LED 20 and a reflector body 110 are mounted on each finned body 100 at the front seat 2.

The finned body 100 can be fixed to the plate 201 by screwing in correspondence with the threaded front attachment portion 5 of Fig. 1, adding to paint or conductive paste, for example based on silver or any other suitable commercial product. In this way, the plate 200, made of heat-conducting material, also contributes with its large surface to the cooling of the finned body 100. The external frame of the appliance 200 also favors heat exchange.

In such a multiple configuration, it is possible to realize a luminaire having any number of power LEDs. In particular, the plate acts as a support for the array of elementary lighting devices (in the figures an array of nine elements is shown purely by way of example). By placing the plate 200 with the first face 202 towards the top, the array of elementary lighting fixtures is automatically cooled whatever the lighting power of the fixture. For example, the plate can be suspended at the desired height as shown in Fig. 12 with the second face 203 facing downwards. The number of elementary luminaires in the array can be chosen according to the required luminance. In this way it is possible to create luminaires even with hundreds of elements, for example to illuminate large rooms such as gyms, theaters, warehouses.

In a floor lamp type embodiment (Fig. 14), the plate 201 can have the first face 202 facing downwards, and the second face 203 facing upwards, to illuminate upwards, and a plurality of holes 204 through the plate for the passage of hot air upwards through the plate 201 itself.

The first face 202 can be protected in a way that is not shown by a grille, capable of easily allowing a flow of air to pass.

The above description of a specific embodiment is able to show the invention from a conceptual point of view so that others, using the known technique, will be able to modify and / or adapt this specific embodiment in various applications without further research. and without departing from the inventive concept, and, therefore, it is understood that such adaptations and modifications will be considered as equivalent to the specific embodiment. The means and materials for carrying out the various functions described may be of various nature without thereby departing from the scope of the invention. It is understood that the expressions or terminology used have a purely descriptive purpose and therefore not limitative.

Claims (10)

CLAIMS 1. A finned body for a power LED lighting fixture comprising: - a monoblock in heat conducting material, called monoblock having a front portion with a front seat for applying a power LED and a rear finned portion, in which said rear finned portion comprises: - starting from a certain distance D from said front seat, a first flat notch ending in correspondence with a solid root with circular section of a given diameter Φ, forming between said first notch and said frontal seat a support base having thickness D; - starting from a determined distance D1 greater than D from said front seat, a second flat notch that ends in correspondence with a solid root of said material with a specific diameter section Φ1, forming between said first and second notch a first fin A1; - starting from a determined distance D2 greater than D1 from said front seat, a third flat notch that ends in correspondence with a solid root of said material with a specific diameter section Φ2, forming between said second and third notch a second fin A2; - further flat notches which together with said first, second, third notch form said rear finned portion, forming a respective fin Ai between two consecutive notches, until a last fin An is obtained, each fin Ai of said rear finned portion being a distance from a preceding fin, and each fin extending from a circular root filled with said material having a cross section with a diameter Φi. 2. A finned body, according to claim 1, in which the distances are constant, while the diameters Φi are decreasing. 3. A finned body, according to claim 1, in which a first group of fins with radius r1 and a second group of fins with radius r2 greater than r1 are provided, starting from said front seat towards said last fin An. 4. A finned body, according to claim 1, wherein said finned body comprises an attachment portion, front threaded externally at said support base, suitable for allowing the coupling of the finned body with a support sleeve, said support sleeve being able to support a reflector body and to allow recess, for example in false ceilings, walls, etc., in particular said threaded front attachment portion is treated with a thermal conductive paste, for example based on silver. 5. A finned body, according to claim 6, in which first through holes are formed on said front seat which pass through said finned body starting from said front seat towards said last fin, said first holes being adapted to receive power cables of said Power LEDs, in particular on said front seat there are obtained second through holes, in particular arranged more externally with respect to said first through holes which pass through said finned body starting from said front seat towards said last fin, said second holes being able to allow an axial flow of air and favor the heat exchange, in particular in the case of a finned body enclosed in an external casing. 6. A finned body, according to claim 1, in which said finned body is anodized aluminum, in particular black anodized aluminum, achieving excellent thermal conductivity even on the surface, increasing the efficiency and duration of the power LED. 7. A lighting device with power LEDs is characterized in that it comprises a finned body made according to the preceding claims, on said finned body being mounted, in correspondence with said front seat, said power LED, and a reflector body, in particular, an external tubular casing is connected to said finned body having a bottom in which passage openings are formed, in particular, said external tubular casing is fixed to said finned body by means of an annular ring having a plurality of axial holes engages on said support base, in particular, between said tubular casing and said reflector body there is provided a perforated annular mask which allows the passage of air between the outside of said tubular casing and said front space. 8. A lighting device with power LEDs is characterized in that it comprises a plurality of finned bodies made according to the preceding claims and mounted on a plate made of heat-conducting material so as to all protrude from a first face of said plate, and in such a way that each front seat of said finned bodies protrudes from a second face of said plate opposite to said first face, on each finned body being mounted, in correspondence with said front seat, a respective power LED and a reflector body. 9. An LED light spotlight is characterized in that it comprises a finned body made according to the preceding claims. 10. A method for manufacturing a finned body comprising the steps of: â € “prepare a monobloc in heat-conducting material; â € “create a seat for the application of a power LED on a front seat of said monobloc; - bring said monobloc into rotation; - make a first plane notch on said monoblock, with a cutting tool having a thickness of less than 3mm, starting from a certain distance D from said front seat, until leaving a solid root with a circular section of a determined diameter Φ ; - move said cutting tool by a distance d1 greater than D from said front seat and make a second flat notch until leaving a circular root filled with said material with a section having a determined diameter Φ1; - move said cutting tool by a distance d2 greater than d1 from said front seat and make a second flat notch until leaving a circular root filled with said material with a section of determined diameter Φ2; - repeat this operation until a single finned body is obtained, in which each fin Ai is at a distance of from the previous fin, and each fin extends from a circular root filled with said material with a diameter Φi, said body finned ending with a last fin An.