Cooling system for cooling a light source in a light module

Abstract

Cooling system (1) for cooling a light source (11) in a light module (10) of a lighting device of a vehicle, in particular a headlight, comprising a receiving body (12) of the light module (10) for receiving the light source (11) and a heat sink (13) arranged at a distance from the receiving body (12), and wherein a heat transfer medium is arranged between the receiving body (12) and the heat sink (13) by means of a heat pipe (14) for heat transfer, wherein the heat pipe (14) is connected to the receiving body (12) with a hot side and to the heat sink (13) with a cold side, wherein the heat pipe (14) has at least a section of a flexible area (15) so that the receiving body (12) is movable relative to the heat sink (13) while maintaining heat transfer, wherein the flexible area (15) is limited to a section of the heat pipe (14).such that the heat pipe (14) has, through the flexible section (15), a first pipe section (14a) connected to the receiving body (12) and a second pipe section (14b) connected to the cooling element (13), wherein the pipe sections (14a, 14b) are movable relative to each other and form a two-part outer pipe (18), wherein the flexible section (15) is formed by at least one flexible sleeve (16, 17) made of a plastic or of a natural rubber, wherein the pipe sections (14a, 14b) are connected to each other by the flexible sleeve (16, 17), and wherein a continuous capillary structure (20) is arranged on the inside of the outer pipe (18) and the flexible sleeve (16, 17), which is configured to follow a flex movement of the flexible sleeve (16, 17).

Description

[0001] The present invention relates to a cooling system for cooling a light source in a light module of a lighting device of a vehicle, in particular a headlight, comprising a receiving body of the light module for receiving the light source and a heat sink arranged at a distance from the receiving body. A heat pipe comprising a heat transfer medium is arranged between the receiving body and the heat sink for heat transfer. The heat pipe is connected to the receiving body with a hot side and to the heat sink with a cold side. Furthermore, the invention is directed to a lighting device for a vehicle, in particular a headlight, comprising such a cooling system. STATE OF THE ART

[0002] DE 10 2004 017 454 B4 discloses a cooling system for cooling a light source in a light module of a lighting device, and the lighting device is designed as a headlight for a vehicle. The housing of the lighting device accommodates several light modules, and the light modules form a light field with mutually different light distribution patterns, for example, for generating a low beam for a vehicle. The light modules are rigidly connected to one another via a common mounting body, and a heat transfer tube is arranged on the mounting body. A heat sink is located in an opening in the housing and is rigidly connected to the mounting body via the heat transfer tube, and thus rigidly connected to all the light modules in the housing of the lighting device.The unit consisting of the light modules is movable in the housing of the lighting device by means of several alignment screws, for example for the basic adjustment of the light modules in the lighting device.

[0003] In principle, the accommodation of light modules in the housing of a lighting device requires mobility in order to carry out the basic adjustment of the light modules in the housing at least at the factory. Furthermore, lighting devices are known which require the movement of at least one light module even during operation of a vehicle, for example to enable headlight range adjustment or a cornering light function. Since the heat sink is rigidly connected to the light modules via the heat pipe, the heat sink must also execute every adjustment movement of the light modules. For this purpose, a seal is provided for the alignment adjustment, which sits in the opening in the housing of the lighting device and completely encloses the heat sink. The seal must be dimensioned such that sufficient freedom of movement of the heat sink is possible in the opening in the housing.

[0004] The adjustment mechanism for the light modules in the lighting unit's housing is based on alignment screws, which only allow for a factory-set basic adjustment of the light modules in the housing. The cooling system shown, with its rigid connection between the heat sink and the light modules, does not allow for movement of the heat sink for headlight range adjustment or cornering light functions, as the adjustment ranges would be too large.

[0005] The fanless cooling system shown is advantageous for energy-saving reasons. However, light modules that feature headlight range adjustment or cornering light functions should generally be designed with the lowest possible mass to minimize inertial and acceleration forces acting on the light module's suspension. Mechanically decoupling a light module from a required heat sink is advantageous, which is particularly achieved when the heat sink is located remotely from the light module. Particularly effective heat dissipation from lamps within the housing of a lighting device can be achieved, in particular, when a heat sink is arranged at least partially on the outside of the housing of the lighting device.

[0006] DE 20 2010 014 452 U1 discloses a flexible cooling device comprising a heat conducting element having a main body which has a heat receiving part and a first connecting part, wherein the first connecting part forms a sphere at the end facing away from the main body, and a cooling element having a base part and a cooling part which are connected to one another, as well as a second connecting part, wherein the second connecting part forms a sphere trough for receiving the sphere at the end facing away from the base part, whereby the sphere is freely movable.

[0007] CN 103 292 195 A discloses a multi-part LED lamp comprising: a heat sink having a metal cavity, the top of the heat sink being provided with a vapor outlet; an LED chip mounted on the outer surface of the bottom of the heat sink; a heat sink having a metal cavity and a vapor inlet at the bottom of the heat sink; a metal bellows having one end connected to the vapor outlet of the heat sink and the other end connected to the vapor inlet of the heat sink; a power supply mounted on the top of the heat sink, the power supply being electrically connected to the LED chip; and a plurality of fins mounted on the outer side wall of the heat sink.

[0008] US 2008 / 0247177 A1 discloses a luminescence device comprising: a light source; a housing for accommodating the light source; a heat dissipation member including a heat transfer portion and a heat dissipation portion and extending through the housing, wherein the heat transfer portion is attached to the light source and the heat dissipation portion is disposed outside the housing; a sealing portion for sealing a gap between the heat dissipation member and the housing; and an optical axis adjusting device for adjusting an optical axis of the light source, wherein the heat transfer portion or the sealing portion is deformable to follow an angular change of the optical axis of the light source by the optical axis adjusting device. DISCLOSURE OF THE INVENTION

[0009] The object of the invention is to further develop a cooling system for cooling a lamp in a light module of a lighting device, which overcomes the disadvantages of the prior art described above. In particular, the cooling system should be designed in such a way that, with a heat sink arranged decoupled from the light module, an expanded range of motion of the light module is created.

[0010] This object is achieved by a cooling system according to the preamble of claim 1 and by a lighting device according to the preamble of claim 4 with the respective characterizing features. Advantageous developments of the invention are specified in the dependent claims.

[0011] The invention includes the technical teaching that the heat pipe has a flexible region at least in sections, so that the receiving body is movable relative to the heat sink while maintaining the heat transport, wherein the flexible region is limited to a section of the heat pipe, so that the heat pipe has a first pipe section connected to the receiving body and a second pipe section connected to the heat sink through the flexible region, wherein the pipe sections are movable relative to one another and form a two-part outer pipe, wherein according to the invention the flexible region is formed by at least one flexible sleeve made of a plastic or of a natural rubber, wherein the pipe sections are connected to one another by the flexible sleeve, and wherein on the inside of the outer pipe and the flexible sleeve a continuous capillary structure is arranged, which is designed toto follow a flex movement of the flexible cuff.,

[0012] The invention is based on the basic idea of ​​making the heat pipe flexible, at least in sections, so that the light module can be moved within the housing of the lighting device, while the heat sink can be arranged stationary in or on the housing. This advantage is achieved by a flexible region in the heat pipe that is formed at least in sections, wherein the flexible region is located between the hot side and the cold side of the heat pipe. The hot side can thus be arranged on the receiving body, and the cold side can be connected to the heat sink, so that despite a rigid connection of the hot side to the receiving body and the cold side to the heat sink, mobility of the receiving body relative to the heat sink is created.The at least one flexible region of the heat pipe should be designed in such a way that sufficient mobility of the light module in the housing is possible, while the heat sink is essentially fixed in place in or on the housing.

[0013] According to the invention, the flexible region is limited to a section of the heat pipe, so that the heat pipe, through the flexible region, has a first pipe section connected to the receiving body and a second pipe section connected to the heat sink. The pipe sections are movable relative to one another and can be rigid in themselves. In particular, the pipe sections can be rigid over their substantial length and each border the flexible region.

[0014] The flexible section is formed by a flexible sleeve. The heat pipe has an outer tube, and the outer tube of the respective first and second pipe sections can be inserted into the flexible sleeve. The heat transfer medium can flow back and forth through the flexible sleeve between the hot side and the cold side.

[0015] According to an advantageous embodiment, the lighting device can have a housing, wherein the heat sink is accommodated in an opening in the housing or wherein the heat sink is arranged outside the housing and wherein the heat pipe extends through the opening in the housing. Advantageously, only the heat pipe in the region of the housing passage through the opening needs to be sealed with a sealing element. If the heat sink is arranged outside the housing of the lighting device, particularly effective heat dissipation of the illuminants of the at least one light module can be achieved, for example, by the vehicle's airflow.

[0016] With further advantage, the light module can be movably accommodated in the lighting device for basic adjustment, for forming a headlight range adjustment and / or for forming a cornering light function, wherein the mobility is made possible by the flexible area in the heat pipe.

[0017] The invention further relates to a lighting device for a vehicle, in particular for a headlight, with a cooling system for cooling a light source of a light module accommodated in the lighting device, with a receiving body of the light module for receiving the light source and with a heat sink arranged at a distance from the receiving body, and wherein a heat pipe comprising a heat transport medium is arranged between the receiving body and the heat sink for heat transport, wherein the heat pipe is connected with a hot side to the receiving body and with a cold side to the heat sink, wherein according to the invention the heat pipe has at least a flexible region in sections, so that the receiving body is movable relative to the heat sink while maintaining heat transport, wherein the flexible region is limited to a section of the heat pipe,so that the heat pipe has a first pipe section connected to the receiving body and a second pipe section connected to the heat sink through the flexible region, wherein the pipe sections are movable relative to one another and form a two-part outer pipe. According to the invention, the flexible region is formed by at least one flexible sleeve made of a plastic or natural rubber, wherein the pipe sections are connected to one another by the flexible sleeve, and wherein a continuous capillary structure is arranged on the inside of the outer pipe and the flexible sleeve, which capillary structure is designed to follow a flexing movement of the flexible sleeve. The above-mentioned further features and associated advantages of the cooling system are also taken into account for the lighting device according to the invention. PREFERRED EMBODIMENT OF THE INVENTION

[0018] Further measures improving the invention are described in more detail below, together with the description of a preferred embodiment of the invention, with reference to the figures. It shows: Fig. 1 a schematic view of a cooling system with a heat pipe as a flexible connection between a light module and a heat sink, Fig. 2 a detailed view of the flexible region of the heat pipe according to a first embodiment, Fig. 3 a detailed view of the flexible region of the heat pipe according to a second embodiment not according to the invention and Fig. 4 a detailed view of the flexible region of the heat pipe according to a third embodiment.

[0019] Fig. 1 shows a schematic view of a cooling system 1 for cooling a light source 11 in a light module 10. The light module 10, at least comprising the light source 11 and a receiving body 12 for receiving the light source 11, can be movably accommodated in the housing 21 of a lighting device. The light source 11 is designed as a semiconductor light source and can, for example, comprise an LED or a laser emitter. During operation, the light source 11 can radiate light 25 into a reflector 26, and if the light module 10 is moved, shown by way of example with a double arrow in the receiving body 12, the generated light 25 can also be moved with a corresponding light distribution, as indicated by another double arrow in the beam path of the light 25.

[0020] The light source 11 is cooled via the receiving body 12, wherein the light source 11 is connected to the receiving body 12 in such a way that heat which is generated in the light source 11 during operation is transferred into the receiving body 12.

[0021] The cooling system 1 further comprises a heat sink 13, which is accommodated in an opening 22 in the housing 21 of the lighting device and faces halfway towards the outside of the housing 21. A sealing element 24 serves to seal the heat sink 13 in the housing 21, wherein the arrangement of the heat sink 13 in the opening 22 is shown merely by way of example, and the heat sink 13 is fixedly seated in the opening 22 of the housing 21. The sealing element 24 creates a seal between the heat sink 13 and the housing 21, and the heat sink 13 can be particularly advantageously dissipated by outside air, which flows around the lighting device, in particular with a headwind during operation of a vehicle, in particular by cooling fins 23 facing the outside of the housing 21.

[0022] A heat pipe 14 extends between the receiving body 12 and the heat sink 13; according to an advantageous embodiment, a heat body 14 can also be referred to as a so-called heat pipe. The heat pipe 14 has a flexible region 15, exemplified by a corrugated structure 19 in an outer tube 18 of the heat pipe 14. Within the outer tube 18, which is closed at both its ends, there is a heat transport medium which evaporates on the hot side, formed by contact with the receiving body 12, and flows through the heat pipe 14 towards the cold side, the cold side being formed by contact with the heat sink 13.On the cold side, the heat transport medium condenses again in the outer tube 18, so that the evaporation and subsequent condensation generate a cooling effect on the receiving body 12, and the heat that is removed from the receiving body 12 by the cooling effect is transferred to the cooling body 13 via condensation on the cooling body.

[0023] The flexible section 15 divides the heat pipe 14 into a first pipe section 14a and a second pipe section 14b. The first pipe section 14a is rigidly connected to the receiving body 12, and the second pipe section 14b is rigidly connected to the heat sink 13. The respective connection of the pipe sections 14a and 14b to the receiving body 12 and to the heat sink 13 can be provided in a materially bonded manner, for example, by means of a thermally conductive adhesive, by soldering, or by welding.

[0024] By means of the flexible region 15 according to the invention, for example formed by a wave structure 19 in the outer tube 18 of the heat pipe 14, mobility of the receiving body 12 with the illuminant 11 is achieved, while the cooling body 13 is fixed and thus immovable in the opening 22 in the housing 21.

[0025] Fig. 2 shows an enlarged view of the heat pipe 14 with the flexible region 15, wherein the flexible region 15 according to the illustrated embodiment comprises a flexible sleeve 16. The outer tube 18 is divided into the two tube sections 14a and 14b, and the end sides of the outer tube 18 are seated in receiving ends of the flexible sleeve 16. Because the sleeve 16 is flexible, the first tube section 14a can be moved relative to the second tube section 14b, as indicated by a double arrow. The sleeve 16 is made of a plastic or a natural rubber, for example, PTFE.

[0026] The heat transfer medium shown within the outer tube 18 flows in a vapor phase from the first tube section 14a through the flexible sleeve 16 into the second tube section 14b. A continuous capillary structure 20 is formed on the inside of the divided outer tube 18, for example, comprising copper strands, which are suitable for also carrying out the flexing movement of the flexible sleeve 16. Within the capillary structure 20, the heat transfer medium can flow back in a condensed, liquid state from the second tube section 14b into the first tube section 14a based on a capillary effect, which is also referred to as the wick effect. The vapor flow and the liquid flow are based on a mass flow equilibrium, so that circulation over the entire length of the heat pipe 14 is not disrupted by the subdivision in the outer tube 18 and through the flexible region 15.

[0027] Fig. 3 shows a further exemplary embodiment of the flexible region 15 in the heat pipe 14, which is not according to the invention, wherein the flexible region 15 divides the heat pipe 14 into the first pipe section 14a and the second pipe section 14b. The outer pipe 18 has a corrugated structure 19 designed such that the flexible region 15 is formed as a compliance region in the outer pipe 18. The capillary structure 20 can also be based on an arrangement of copper strands on the inside of the outer pipe 18, and the continuous course of the capillary structure 20 is not negatively influenced by the corrugated structure 19. The mobility of the first pipe section 14a relative to the second pipe section 14b is also indicated by a double arrow.

[0028] Fig. 4 shows yet another exemplary embodiment for forming the flexible region 15 in the heat pipe 14, wherein the outer pipe 18 is again divided into two parts, namely a first part forming the first pipe section 14a, and a second part forming the second pipe section 14b. Both pipe sections 14a, 14b are connected to one another by a flexible sleeve 17, for example formed by a plastic hose section, for example comprising PTFE. The mobility of the first pipe section 14a relative to the second pipe section 14b is again indicated by a double arrow. On the inside of the outer pipes 18 is the capillary structure 20, which also extends beyond the area of ​​the flexible sleeve 17.A central steam flow and a return transport of the condensed heat transport medium by capillary action are therefore not interrupted even when a flexible sleeve 17 is arranged in the manner of a hose section.

[0029] The embodiments for the formation of the flexible area 15 in the heat pipe 14 according to the Fig. 2, Fig. 3 and Fig. 4 show that circulation of the heat transfer medium is not interrupted even when a flexible region 15 is introduced into the heat pipe 14. Consequently, circulation of the heat transfer medium can occur between the two end sides of the heat pipe 14, i.e., between the hot side and the cold side, as shown by the arrows in the gas phase and in the liquid phase of the heat transfer medium.

[0030] The invention is not limited in its implementation to the preferred embodiment described above. Rather, a number of variants are conceivable, which utilize the presented solution even in fundamentally different embodiments. All features and / or advantages apparent from the claims, the description, or the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in a wide variety of combinations. List of reference symbols 1 cooling system 10 light modules 11 light bulbs 12 receiving bodies 13 heat sinks 14 Heat pipe 14a first pipe section 14b second pipe cut 15 flexible area 16 flexible cuff 17 flexible cuff 18 Outer tube 19 Wave structure 20 Capillary structure 21 housings 22 Opening 23 cooling fins 24 Sealing element 25 light 26 Reflector

Claims

[1] Cooling system (1) for cooling a light source (11) in a light module (10) of a lighting device of a vehicle, in particular a headlight, comprising a receiving body (12) of the light module (10) for receiving the light source (11) and a heat sink (13) arranged at a distance from the receiving body (12), and wherein a heat pipe (14) comprising a heat transport medium is arranged between the receiving body (12) and the heat sink (13) for heat transport, wherein the heat pipe (14) is connected with a hot side to the receiving body (12) and with a cold side to the heat sink (13), wherein the heat pipe (14) has at least in sections a flexible region (15) so that the receiving body (12) is movable relative to the heat sink (13) while maintaining heat transport, wherein the flexible region (15) is limited to a section of the heat pipe (14),such that the heat pipe (14) has, through the flexible region (15), a first pipe section (14a) connected to the receiving body (12) and a second pipe section (14b) connected to the cooling body (13), wherein the pipe sections (14a, 14b) are movable relative to one another and form a two-part outer pipe (18), wherein the flexible region (15) is formed by at least one flexible sleeve (16, 17) made of a plastic or natural rubber, wherein the pipe sections (14a, 14b) are connected to one another by the flexible sleeve (16, 17), and wherein a continuous capillary structure (20) is arranged on the inside of the outer pipe (18) and the flexible sleeve (16, 17), which capillary structure is designed to follow a flexing movement of the flexible sleeve (16, 17). [2] Cooling system (1) according to claim 1, characterized bythat the lighting device has a housing (21), wherein the heat sink (13) is received in an opening (22) of the housing (21) or wherein the heat sink (13) is arranged outside the housing (21) and wherein the heat pipe (14) extends through the opening (22) in the housing (21). [3] Cooling system (1) according to one of the preceding claims, characterized by that the light module (10) is movably accommodated in the lighting device for basic adjustment, for forming a headlight range adjustment and / or for forming a cornering light function, wherein the mobility is made possible by the flexible area (15) in the heat pipe (14). [4] A lighting device for a vehicle, in particular a headlight, comprising a cooling system (1) for cooling a light source (11) of a light module (10) accommodated in the lighting device, comprising a receiving body (12) of the light module (10) for receiving the light source (11), and comprising a heat sink (13) arranged at a distance from the receiving body (12), and wherein a heat pipe (14) comprising a heat transport medium is arranged between the receiving body (12) and the heat sink (13) for heat transport, wherein the heat pipe (14) is connected with a hot side to the receiving body (12) and with a cold side to the heat sink (13), wherein the heat pipe (14) has a flexible region (15) at least in sections, so that the receiving body (12) is movable relative to the heat sink (13) while maintaining heat transport, wherein the flexible region (15) is limited to a section of the heat pipe (14),such that the heat pipe (14) has, through the flexible region (15), a first pipe section (14a) connected to the receiving body (12) and a second pipe section (14b) connected to the cooling body (13), wherein the pipe sections (14a, 14b) are movable relative to one another and form a two-part outer pipe (18), wherein the flexible region (15) is formed by at least one flexible sleeve (16, 17) made of a plastic or natural rubber, wherein the pipe sections (14a, 14b) are connected to one another by the flexible sleeve (16, 17), and wherein a continuous capillary structure (20) is arranged on the inside of the outer pipe (18) and the flexible sleeve (16, 17), which capillary structure is designed to follow a flexing movement of the flexible sleeve (16, 17). [5] Lighting device according to claim 4 with a cooling system (1) according to one of claims 2 or 3.

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