Arrangement of a heatsink in a headlamp

An arrangement of a heatsink for insertion in a headlamp, and a holder being provided in the headlamp, in which the heatsink is held. At least one semiconductor light source is provided, which can be cooled with the heatsink (10). A clamping element is provided, with which the heatsink is arranged in a holding manner on the holder and by means of which one or more semiconductor light sources are directly or indirectly held on the heatsink.

CROSS REFERENCE

This application claims priority to German Application No. 10 2014 109114.0, filed Jun. 30, 2014, the entirety of which is hereby incorporated by reference.

FIELD OF TECHNOLOGY

The present invention relates to an arrangement of a heatsink for insertion in a headlamp, a holder being provided in the headlamp, in which the heatsink is held and wherein at least one semiconductor light source is provided, with which the heatsink can be cooled,

Such arrangements of a heatsink for insertion in a headlamp form so-called light-modules, and the holder can for example form the housing of the headlamp or a carrier frame, on which the heatsink is supported. By this means, the heatsink can for example be arranged rigidly in the housing of the headlamp. The semiconductor light source comprises for example one or several LEDs and for constant operation, the semiconductor light source must often be cooled, the cooling being executed with the heatsink. Herein, the semiconductor light source is either supported directly or via a carrier PCB on the heatsink, and usually the heatsink has machined surfaces for the arrangement on the holder and/or for holding the semiconductor light source, which makes the provision of a heatsink correspondingly more expensive.

BACKGROUND

EP 2 378 323 A2 shows, for example, a heatsink having several functional surfaces, whose manufacture requires milling/cutting. Furthermore, the heatsink has bores, and for the manufacture of the milled or drilled structural characteristics of the heatsink, tool inserts and production steps are required which make the heatsink more expensive. Especially whenever the heatsink is manufactured by means of a pressure die-casting process or a metal extrusion process, the advantages of a finished contour of the heatsink can only be used conditionally, as a respective further, chip-producing treatment is required for the provision of the heatsink.

SUMMARY OF THE INVENTION

The problem of the invention is the arrangement of a heatsink in a headlamp, which is executed as simple as possible and wherein the heatsink design is free from surfaces produced by means of chip-producing processes

The invention includes the technical teaching that a clamping element is provided, with which the heatsink is arranged in a holding manner on the holder and by means of which one or more semiconductor light sources are directly or indirectly held on the heatsink.

Herein, the clamping element according to the invention covers two tasks. First, the heatsink is held on the holder by the clamping element, and second, the semiconductor light source is directly or indirectly held on the heatsink. The arrangement of the semiconductor light source in the sense of the present invention does not require an immediate body contact between the semiconductor light source and the heatsink, an indirect arrangement, for example via a carrier PCB is also possible. Decisive for the use of the advantages according to the invention is, however, that the clamping element holds the heatsink in an elastically prestressed manner on the holder and/or one or more semiconductor light sources on the heatsink. The clamping element may, of course, comprise several parts and may for example comprise a spring element.

By using a clamping element according to the invention, the advantage is achieved that the heatsink is embodied free from machined surfaces and that the heatsink can be manufactured in a simple manner by means of an impact extrusion process, an extrusion process or a pressure die-casting process. If the heatsink is manufactured by means of an impact extrusion process, for example by means of aluminum die-cast or a pressure die-cast or a normal die-cast of alternative, equally suitable materials for the provision of a heatsink, it may then be immediately introduced, e.g. directly or e.g. after a following surface treatment to the arrangement according to the invention. Due to the use of the clamping element, no surfaces or holes requiring cutting or drilling are necessary on the heatsink, as the clamping element serves for the fastening of the heatsink on the holder or for the fastening of the semiconductor light source on the heatsink and as e.g. screws or other elements are not needed.

In addition to the possibility of making a heatsink e.g. from a die-cast part, the fastening according to the invention can also be used for a heatsink being made from a sheet metal part or from a combination of different manufacturing processes.

A heatsink which is for example manufactured in an extrusion process, may also be free from surfaces which have been machined in a chip-producing manner. A saw cut may, however, be necessary to separate the heatsink from a large extruded workpiece. In the sense of the present invention, therefore, a surface which is free from chip-producing machining, refers to processes such as cutting, drilling and such like, to achieve the immediate fastening of the heatsink on the holder or the fastening of the semiconductor light source on the heatsink.

According to an advantageous embodiment for the arrangement of the semiconductor light source, a carrier PCB may be provided, on which the semiconductor light source is supported, wherein the carrier PCB is arranged between the clamping element and a cooling side of the heatsink. When the clamping element clamps the semiconductor light source against the heatsink, the carrier PCB may be in the force flow between the semiconductor light source and the cooling side of the heatsink. The clamping element may for example be embodied and prestressed so that it presses the carrier PCB with direct contact onto the cooling side of the heatsink without the force flow being led through the semiconductor light source itself. To this end, the clamping element may have an opening through which the semiconductor light source can emit light, for example into a light guide element.

According to a further advantage, the clamping element may have centering bosses by means of which the carrier PCB is held in its position on the heatsink. The centering bosses may for example be arranged on the side of the clamping elements facing the cooling side of the heatsink, and the centering bosses, for example in a double arrangement, run through bores in the carrier-PCB and fit in those. The heatsink may have recesses corresponding with the positions of the centering bosses so that the mechanical tension of the clamping element is applied via the carrier PCB to the cooling side of the heatsink. Herein the centering bosses may protrude into the recesses, the recesses themselves having already been produced in the extrusion process or in the impact extrusion process. In an exemplary embodiment, the recesses may be formed as round or rectangular indentations, if the heatsink is manufactured by means of the impact extrusion process, and if the heatsink is manufactured by means of an extrusion process, the recesses may be executed as a continuous longitudinal groove.

According to a further advantageous embodiment of the arrangement according to the invention, it may comprise a light guide element being held in position for the semiconductor light source. On the clamping element, for example, holding shapes can be molded-on, which limit the opening through which the semiconductor light source emits the light; and if the light guide element is arranged in the opening in the clamping element, the light guide element can be held in its position by the molded-on holding shape. Herein, the clamping element has a further function, as by means of the clamping element, the light guide element is held in its position above the semiconductor light source.

According to a further advantageous embodiment of the clamping element according to the invention, it can have a plane extension, beyond which, for example, the centering bosses and/or molded-on holding shapes extend. In particular the clamping element can be fastened to the holder by means of at least one fastening element, preferably executed as a screw-fastening element. By means of this fastening to the holder, the heatsink can be clamped-on at the same time, and the clamping element can, for example, be made from a metal or a plastic material. The clamping element can particularly comprise at least one snap-fastening hook, with which the heatsink is at least partially held. The snap-fastening hook can for example clasp the edge of the heatsink Furthermore, the heatsink can be tightened with the pretensioned clamping element against a clamping edge on the holder, while the tension is deflected through the carrier PCB into the heatsink. The fastening element can therefore serve to arrange the clamping element and therefore also the heatsink on the holder, and at the same time the fastening element applies the pretension to the clamping element. The geometric dimensions between the clamping element, the heatsink and the holder can be embodied so advantageously relative to one another, that by fastening the screw-fastening element the pretension is applied to the clamping element, and the heatsink is fastened on one hand by the snap-fastening hook and on the other hand for example on an opposite side on the clamping edge of the holder.

DETAILED DESCRIPTION OF THE DRAWINGS

The FIGURE shows an arrangement of a heatsink10, as it can for example be inserted in a headlamp, while forming a light module. The arrangement is shown arranged on a holder11, wherein the holder11can for example form the housing of the headlamp, which does not have to be encompassed by the arrangement.

The arrangement has a semiconductor light source12, which is represented exemplarily as a SMD-LED. The semiconductor light source12can radiate into a light guide element17during operation, to fulfil, for example, a light signal function in a vehicle headlamp. Herein, the semiconductor light source12is cooled via the heatsink10, the cooling being achieved by means of and/or through a carrier PCB14, on which the semiconductor light source12is held. The carrier PCB14can for example comprise a respective metal portion or provide a high thermal conductivity by another means.

The heatsink10is held by a clamping element13, and the clamping element13is made from a plastic material, for example by means of an injection molding process. The clamping element13has a plane extension and covers essentially a cooling side10aof the heatsink10. In the position of the semiconductor light source12on the cooling side10aof the heatsink10, the clamping element13has an opening in which a light guide element17is received, so that during operation of the semiconductor light source12, emitted light is radiated into the light guide element17.

The clamping element13is held on the holder11via a fastening element18, which is for example executed as a screw-fastening element19. On the side opposite the fastening element18on the holder, the clamping element13has a snap-fastening hook20which clasps a longitudinal edge of the heatsink. On the side of the fastening element18, the heatsink10sits on a clamping edge21on the holder11, and by tensing the clamping element13by means of the fastening element18a tension is created in the clamping element13. This tensioning results in the pressing of the carrier PCB14with the semiconductor light source12onto the cooling side10aof the heatsink10. At the same time, the heatsink10is held on the holder11by the clamping element and the heatsink10is pressed against the clamping edge21. Therefore, the clamping element fulfils the function of a seat for the heatsink10on the holder11, and the clamping element fulfils the function of the arrangement of the semiconductor light source12on the cooling side10aof the heatsink.

In order to position the light guide element17above the semiconductor light source12in a holding manner according to a further function of the clamping element13, the clamping element13has molded-on holding shapes22, between which the light guide element17is held, and the molded-on holding shapes22limit for example the opening in the clamping element13. In a manner not shown in detail, the light guide element17can for example be snap-fastened to the clamping element13and particularly to the molded-on holding shapes22.

Furthermore, the clamping element13has centering bosses15, which are positioned on the side of the clamping elements13on which the carrier PCB14is arranged and which faces in the direction of the cooling side10aof the heatsink10. The centering bosses15penetrate the carrier PCB14through the added bores, so that the carrier PCB14is held in its position and the semiconductor light source12, which is for example fastened on the carrier PCB14in a conventional manner, is held in the opening in the clamping element13.

According to the shown embodiment, the heatsink10can be embodied free from surfaces which have been machined with chip-producing processes. Except from this embodiment of the heatsink10is a surface of the heatsink10, which is formed by means of a saw cut, for example to cut the heatsink10from an extruded profile.

In an exemplary embodiment, the heat sink10has not screw bores or other surfaces machined with chip-producing processes, particularly due to the fastening method with the clamping element13, and also in the position, in which the carrier PCB14is arranged on the cooling side10aof the heatsink10, there are no surface treatments with chip-producing processes necessary. The surface which can be produced by means of an extrusion process or an impact extrusion process, for example when the heatsink10is made from aluminum, can be sufficient to achieve a face-to-face cooling contact for example with the carrier PCB14. In order for the centering bosses15not to sit on the cooling side10aof the heatsink10and weaken the tensioning of the carrier PCB14, the cooling side10ahas recesses16which can also be already produced by means of an extrusion process or impact extrusion process. The recesses16merely show in an exemplary embodiment, that the heatsink10acan have respective contours which are for example necessary for a carrier PCB14, despite missing chip-producing processes.

The clasping of the clamping element13around the outer edge of the heatsink10is merely shown in an exemplary embodiment with the snap-fastening hook20. Exemplarily, the lateral side of the heatsink10can be profiled accordingly, and achieve a form-fit also in a different manner, particularly with the clamping element13, but also with the holder11.

In its execution, the invention does not relate solely to the preferred design example described above. On the contrary, a number of variants that use the solution as represented above are conceivable, even on designs that are fundamentally different. All characteristics resulting from the claims, the description or the drawings and/or advantages, including design details, arrangements in space and process steps can be essential for the invention on their own as well as in any combination.

LIST OF REFERENCE SIGNS