EP1749171B1 - Headlight with heat exchanger for cooling the lighting means - Google Patents

Abstract

A headlight, in particular a motor vehicle headlight, has the following features: the headlight has a compression aggregate (1) for generating a conveying force for a coolant which is conveyed through the headlight for cooling the lighting means (6, 7); the headlight has a heat exchanger (2) for conveying heat from the coolant to the headlight surroundings; and the headlight has means for controlling and/or regulating the compression aggregate (1).

Description

The invention relates to a headlight, in particular a motor vehicle headlight with the features of the preamble of claim 1.

Such a headlight is for example from the publication with the publication number DE 102 13 680 A1 known. In this document, a cooling circuit is provided in which the heated air from the lamp by means of a printing unit, it is a fan, is sucked out of the housing of the headlamp and is passed through a heat exchanger to cool the air. At the heat exchanger, the air is then transported back into the housing of the headlamp.

A disadvantage of the disclosed in the document headlight is that regardless of the temperature, which has the air in the housing headlamp, and regardless of the current cooling capacity of the heat exchanger, the printing unit is switched on with the same power. The cooling capacity of the heat exchanger is to a considerable extent dependent on which temperature and which flow velocity the cooling medium has, with which the heat exchanger is flown in order to cool the air transported in the cooling circuit. Due to the constant operation of the printing unit printing units are required, which have a long life, which leads to increased costs.

The invention is therefore based on the object to propose a headlight in which the printing unit is not stressed so much.

From the prior art, a headlamp is also known, in which the air flow is directed so that it is passed directly to the bulbs and / or heat sinks of the bulbs. As a result, a better dissipation of heat from the lamps and the heat sinks is effected. The headlight, as in the publication DE 198 14 300 A1 is disclosed, has in its housing through openings, which allows an exchange of air between the environment of the headlamp and the headlight interior. Thus, the headlight can be flowed through, for example during a drive of the motor vehicle by the wind, which then enters the housing of the headlamp, is passed past the bulbs to cool them and then exits from further passages again. A disadvantage of this headlight is that through the openings in the housing moisture and dirt can penetrate into the headlight. This is not desirable.

The invention is therefore also the object of the publication DE 198 14 300 train known headlights so that moisture in the headlight housing can no longer occur.

ADVANTAGES OF THE INVENTION

This object is achieved with a headlamp with the features of claim 1. Such a headlight has in addition to the features mentioned in the preamble of claim 1 second illuminant. The second lighting means are arranged on a second separating element, which in the region of Second light emitting means has passage openings for the fluidic connection of the second air duct section with the third air duct section. Incidentally, the second separating member separates the second air guiding portion from the third air guiding portion. Such a headlight unites on the one hand, the concept of the closed cooling circuit, as it is basically from the document DE 102 13 680 A1 is known with the idea to selectively flow to the cooling lamps and their heat sink with the cooling medium. In this case, the invention makes use of the further knowledge that not all lamps must be cooled in parallel alike cooled by the heat exchanger air. Thus, it is quite possible to group bulbs so that the first bulbs are first flowed, while only then the second bulbs are then flown with the then already warmed by the first bulbs air. In order to implement this concept, the air guiding sections arranged one behind the other are provided in the invention.

An inventive headlight has a means for controlling and / or controlling the printing unit.

By the means for controlling and / or controlling the printing unit, the power of the printing unit can be adjusted according to the temperature of the recirculated in the headlight or the secondary side of the cooling medium and / or according to the flow rate at the secondary side of the heat exchanger.

Advantageously, such a headlamp on at least one sensor for the flow rate and / or a temperature sensor, with the means for controlling and / or Rules connected. Depending on the flow velocity measured by the sensor or the temperature measured by the temperature sensor, the power of the pressure generator can then be regulated by the means for controlling and / or regulating. For example, the secondary side of the heat exchanger can be flown with the ambient air, wherein the flow rate changes depending on the speed of the motor vehicle in which the headlamp may be installed. At a high outside temperature and in particular at standstill of the vehicle then the air in the headlight must be circulated at a higher speed than for example at lower ambient temperatures and very high speed of the motor vehicle. Temperature sensors may also be adapted to directly detect the temperature of the recirculated air and then to control the temperature of this recirculated air to prevent overheating of the illuminants.

The danger of overheating of bulbs is particularly important in modern headlamps, when light emitting diodes are used as the light source. Light-emitting diodes usually tolerate a temperature of about 120 to 130 ° C. If this temperature, the so-called junction temperature, is exceeded, the light-emitting diodes are destroyed.

Preferably, a housing of the heat exchanger, a holder for the printing unit and a housing of the printing unit can be made of the same plastics as a housing of the headlamp itself. The material may be, for example, PP-TV. The housing of the heat exchanger and the housing of the blower can be more integral Be part of the housing of the headlamp. Furthermore, it is advantageous if a possibility is provided in the heat exchanger to dissipate liquid precipitating in the housing of the headlight. A drainage opening provided for this purpose can simultaneously serve as a pressure compensation opening for the headlight housing.

On the secondary side, the heat exchanger can be connected to a low-temperature cooling circuit, for example, an air conditioner.

The air duct sections may be formed in whole or in part by one or more air ducts. These air ducts can in turn be formed by pipes and / or hoses.

The first luminous means and / or the second luminous means can be arranged in the passage openings of the first separating element or the second separating element or project into these passage openings. The first lighting means and / or the second lighting means can also be connected with a heat sink. Then, the heat sink can be arranged in the passage openings of the separating elements or protrude into these passage openings. The first separating element and / or the second separating element can be arranged pivotably in the housing, so that it is possible to pivot the first and / or the second lighting means in the housing in order to control the direction of the For example, to change headlamps of leaking light for headlamp leveling.

In a particularly advantageous embodiment of the headlamp and individual light sources can be pivotally mounted on the separating elements. This can be advantageous for a headlamp with a so-called cornering light.

DRAWINGS

Fig. 1

eine schematische Darstellung eines ersten erfindungsgemäßen Scheinwerfers im Schnitt,

Fig. 2

eine schematische Darstellung eines zweiten erfindungsgemäßen Scheinwerfers im Schnitt,

Fig. 3

ein schwenkbar in einem erfindungsgemäßen Scheinwerfer angeordnetes Leuchtmittel,

Fig. 4

einen Wärmetauscher eines erfindungsgemäßen Scheinwerfers,

Fig. 5

einen Wärmetauscher eines weiteren erfindungsgemäßen Scheinwerfers,

Fig. 6

einen Schnitt durch ein Innenrohr eines Wärmetauschers gemäß Fig. 5 in einer alternativen Ausführung und

Fig. 7

einen Schnitt durch das Innenrohr eines Wärmetauschers gemäß Fig. 5 in einer weiteren alternativen Ausführung.

Embodiments of inventive headlights and details inventive headlights are described in more detail with reference to the drawing. It shows

Fig. 1

a schematic representation of a first headlamp according to the invention in section,

Fig. 2

a schematic representation of a second headlamp according to the invention in section,

Fig. 3

a lamp arranged pivotally in a headlight according to the invention,

Fig. 4

a heat exchanger of a headlight according to the invention,

Fig. 5

a heat exchanger of a further headlight according to the invention,

Fig. 6

a section through an inner tube of a heat exchanger according to Fig. 5 in an alternative embodiment and

Fig. 7

a section through the inner tube of a heat exchanger according to Fig. 5 in a further alternative embodiment.

DESCRIPTION OF THE EMBODIMENTS

The in Fig. 1 shown inventive headlamp has a housing 13, 14, which consists of a lower housing part 13 and an upper housing part 14, wherein the upper housing part is transparent and the light emitted by the light sources 6, 7 light from the headlight housing 13, 14 allows.

In the lower housing part, an outlet opening for a heat exchanger 2 is provided. The heat exchanger 2 serves to dissipate the heat generated by the lighting means 6, 7 during the generation of the light from the housing of the headlight 6, 7. The heat exchanger 2 is connected to the suction side of a pressure unit 1, in the present case is a fan. The pressure side of the printing unit 1 is connected to a first air duct 3 of the headlamp. The air conduction region 3 is delimited by a tube 11 and first separating elements 8 which separate the first air conduction region 3 from a second air conduction region 4. Only via passage openings 10 in the first separating element 8, the first air duct 3 is connected to the second air duct 4.

In the passage openings 10 are connected to the first lighting means 6 connected cooling body 12, or protrude the heat sink 12 partially into the passage openings 10 into it. Lenses 15 are assigned to the first light sources 6, which focus the light generated by the first light means 6 and direct them in the direction of the transparent upper housing part 14.

The sucked by the printing unit 1 from the heat exchanger 2 air can be blown during operation of the printing unit via the first air duct 3 through the passage openings 10 on the heat sinks 12 and the first light means 6 over in the second air duct 4. In this case, the cool air sweeps past the heat sink 12 of the first light-emitting means 6 and to these light-emitting means 6 itself and dissipates heat from the heat sink 12 or the first light-emitting means 6.

The thus heated air is supplied to the heat exchanger 2. For this purpose, a third air duct 5 is provided. This third air guiding region 5 is delimited by a pipe 11 and a second separating element 9. The second separating element 9, like the first separating element 8, has passage openings 10. About this there is a connection to the second air duct 4. Also in these openings 10 bulbs, namely second light source 7 are arranged. These second lighting means are also connected to a heat sink 12, which protrude into the passage openings 10 of the second separating element 9.

One of these second light sources 7 is assigned a reflector 16, which focuses the light generated by this second light source 7 and directs it in a desired direction. The remaining second light sources 7 are associated with lenses 15, which focus the light of these bulbs 7 and direct in the direction of the transparent upper housing part 14.

The third air duct 5 is not only connected to the second air duct 4, but also - as already stated - with the heat exchanger 2. This creates a closed circuit for the air. From one side of the heat exchanger 2, the cold air through the pressure unit through the first air guide 1 at the first light sources 6 transported over into the second air duct 4. In this case, the air from the first light means 6 generates heat. The air is then transported past the second light-emitting means 7 past the second air-conduction region 4 through the passage openings 10 into the third air-conduction region 5. In this case, the air already heated by the first lighting means 6 passes the second lighting means 7 and the cooling bodies 12 associated with these second lighting means 7 and also absorbs heat from these lighting means 7. In the heat exchanger 2, the air is removed from the heat, so that on the cold air side of the heat exchanger again cold air is available in sufficient quantity to the bulbs on to bring the desired operating temperature.

The bulbs are according to the representation of the Fig. 1 In order to light-emitting diodes, in principle, however, such a headlight is also conceivable with other light sources.

The Indian Fig. 2 illustrated inventive headlamp has features that according to the features of the headlamp according to at least in their function Fig. 1 correspond. These features are in the Fig. 2 Therefore, provided with the same reference numerals as in Fig. 1 , So the headlight according to Fig. 2 in particular a heat exchanger 2, a printing aggregate 1, a first air conduction region 3, a second air conduction region 4, a third air conduction region 5, first illumination means 6, second illumination means 7, heatsinks 12 and lenses 15 associated with the illumination means, and a first separation element 8 and a second separation element 9 on.

Unlike the headlight according to Fig. 1 However, the first air duct 3 and the second air duct 4 is not bounded by a pipe. Instead, the first air-conducting region 3 and the third air-conducting region 5 are bounded by the housing 13 and the first separating element 8 or the second separating element 9. A third separating element 23, 24 also adjoins the first air-conducting region 3 against the third air-conducting region 5 and vice versa.

The first separating element 8, the second separating element 9 and a first part 23 of the third separating element 23, 24 are integrally connected to one another. This thus formed total separating element 8, 9, 23 is rotatably mounted in a rotary bearing 18 on the lower housing part 13 of the housing 13, 14. This allows, for example, a headlight range adjustment of the headlight. By pivoting the entire separating element 8, 9, 23 with the attached first light means 6, second light sources 7, heat sinks 12 and lenses 15, it is possible to adjust the direction of the light emerging from the transparent upper housing part 14 light beam.

By sealing regions 17 between the first separating element 8 and the second separating element 9 on the one hand and the lower housing part 13 on the other hand and by a sliding connection between the first part 23 and a second part 24 of the third separating element 23, 24 ensures that even after or during a pivoting of the Total separation element 8, 9, 23 with the associated attachments the desired path of the air from the first air duct 3 to the second air duct 4 is further specified in the third Luftleitabschnitt 5 and a fluidic short circuit is excluded, for example, between the first air duct 3 and the third Luftleitabschnitt 5, as well as a direct transition of the air from the first air duct 3 into the second air duct 4, or from the second air duct 4 into the third air duct 5, bypassing the Through openings 10. As a result, the constant flow of the heat sink 12 and the first light source 6 and the second light source 7 is secured.

That in the Fig. 3 shown detail of a headlight according to the invention shows a first or second lighting means 6, 7, which is pivotally mounted in a first and second separating element 8, 9 is arranged. On the separating element 8, 9 two opposite tabs 25 are provided for this purpose, which are arranged on both sides of the passage opening 10 of the separating element 8, 9. At these tabs 25, the heat sink 20, 21, which is assigned to the bulbs 6, 7, rotatably mounted. At this heat sink 20, 21 then both the light source 6, 7 and the lens 15 associated with the lamp is attached.

The heat sink 20, 21, 26 has a sleeve-like left portion 26, which rests tightly against the separating element 8, 9 via a sealing region 27. The sealing region 27 between the separating element 8, 9 and the left portion 26 is formed by a ball or cylindrical surface around the pivot axis 19 of the heat sink. This ensures that air which passes through the passage openings 10 is passed through the left portion 26 of the heat sink, and can not pass between the separator 8, 9 and the left portion 26 of the heat sink. In the left portion 26 of the heat sink 20, 21, 26 radial webs 21 are provided. At a core in the center of the heat sink, the light source 6, 7 is attached. At the left portion 26 close in a right portion of the heat sink to holding webs on which the lens 15 is attached.

At the left end of the lower portion 26 of the heat sink, a pivot lever 22 is pivotally mounted, via which a force can be exerted on the heat sink to the Heatsink to pivot with the attachments attached thereto about the pivot axis 19. This makes it possible to change the direction of the light generated by the bulbs 6, 7 by an actuation of the pivot lever 22. This may be necessary, for example, in motor vehicle headlights for the dynamic cornering light.

The in Fig. 4 illustrated heat exchanger of a headlight according to the invention has first channels 31 and second channels 32, which are alternately guided side by side through the heat exchanger. The second channels 32 serve to transport the circulated in the headlight air, while the first channels 31 serve to receive air from the outside. The air taken in from the outside is passed through the heat exchanger in countercurrent to the air circulated in the headlight and the second channels 32. By dividing into a plurality of first channels 31 and second channels 32, the surface between the first channels 31 and the second channels 32 is increased, which allows efficient heat exchange between the channels 31, 32 in a small space. Between the channels very thin-walled metal sheets or plastic walls may be used to minimize the heat transfer resistance.

The in Fig. 5 illustrated heat exchanger of a heat exchanger according to the invention has a first channel 31 through which the outside air is guided to cool the guided through a second channel 32 in the headlight circulated air. The first channel 31 is formed by a tube (inner tube), which is concentrically surrounded by a second tube. This second tube is widened at its ends and also lies close to the first tube. Via lateral connecting pieces 32a, 32b, the air circulated in the headlight is conveyed into or out of the intermediate space between the first pipe and the second pipe. The air streams through the first channel 31 and the second channel 32 are thereby transported in countercurrent, so that an efficient cooling of the circulated in the headlight air is possible.

Instead of the first tube, the separation between the first and the second channel 31, 32 can also be formed by a ribbed, extruded hollow profile, as shown in FIG Fig. 6 is shown in section. In this extruded hollow profile, the surface between the first channel and the second channel is increased, which allows a more efficient heat exchange.

Likewise, a tube folded from sheet metal can be used as it is in Fig. 7 is shown in section.

Claims (9)

1. Headlamp, and in particular an automotive headlamp with the following characteristics:

   - The headlamp comprises a pressure unit (1) to generate a transport force for a cooling medium being guided through the headlamp for the cooling of light sources (6, 7);

   - The headlamp comprises a heat exchanger (2) for the transport of heat from the cooling medium to an environment of the headlamp,

   - The headlamp comprises a first air duct section (3), a second air duct section (4), a third air duct section (5) and first light sources (6);

   - The first air duct section (3) is connected fluidically to the pressure side of the pressure unit (1);

   - The first light sources (6) are arranged on a first separating element (8) having openings (10) in the region of the first light sources (6) for the fluidic connection of the first air duct section (3) with the second air duct section (4) and, in addition, separating the first air duct section (3) from the second air duct section (4);

   - The third air duct section (5) is connected fluidically with the intake side of the pressure unit (1) by means of the heat exchanger (2).
   Characterized in that

   - The headlamp comprises second light sources (7),

   - The second light sources (7) are arranged on a second separating element (9) having openings (10) in the region of the second light sources (7) for the fluidic connection of the second air duct section (4) with the third air duct section (5) and, in addition, separating the second air duct section (4) from the third air duct section (5), and

   - The headlamp comprises a means for the controlling of the pressure unit (1).
2. Headlamp according to claim 1, characterized in that the headlamp comprises at least one pressure sensor and/or one temperature sensor being connected with the means for controlling, and that, depending on the pressure measured by the pressure sensor, or the temperature measured by the temperature sensor the performance of the pressure unit (1) is controllable by means of the control means.
3. Headlamp according to claim 1 or 2, characterized in that the first air duct section (3) and / or the second air duct section (4) comprises on or more air ducts.
4. Headlamp according to claim 3, characterized in that the air ducts are formed by means of pipes (11) and or hoses.
5. Headlamp according to one of the claims 1 to 4, characterized in that the first light sources (6) and/ or the second light sources (7) are arranged in the opening (10) of the first separating element (8) and the second the second separating element (9) respectively or protrude into this opening (10).
6. Headlamp according to one of the claims 1 to 5, characterized in that the first light sources (6) and/or the second light sources (7) are connected to one cooling element (12) each.
7. Headlamp according to claim 6, characterized in that the cooling elements (12)are arranged in the openings (10) of the first separating element (8) and in the second separating element (9) respectively, or protrude into these openings (10).
8. Headlamp according to one of the claims 1 to 7, characterized in that the first separating element (8) and/or the second separating element (9), is arranged swiveling in the housing (13, 14).
9. Headlamp according to one of the claims 1 to 8, characterized in that the first light sources (6) and/ or the second light sources (7) are supported on the separating elements (8, 9) at least partly in a swiveling manner.

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