FR3028004A1 - SEMI-ELLIPTICAL PROJECTOR COMPRISING A RADIATOR - Google Patents

Abstract

Motor vehicle headlamp comprising a light source (S) a moving means and a movable optical element configured to be driven by said moving means and arranged to cut and / or reflect a light beam emitted by the source, characterized in that it comprises a radiator thermally connected to said moving means.

Description

The field of the present invention is that of automotive equipment and, more particularly, that of the light projectors for these motor vehicles. Motor vehicle headlamps generally comprise a lens and a reflector in which a light source is disposed. It is known to use a cutoff bar allowing various phases of occultation of the light beam. The bar is then actuated electrically by a motor to move, on command, between at least two angular positions in which it more or less obscures the light beam. This makes it possible to limit the range of the headlamp, for example to that of the dipped headlamps, called the code position, so as not to dazzle the drivers traveling in the opposite direction, or to that of the high beam, called the road position, in which it There is no occultation. This technology is commonly used with projectors having a high power light source, such as halogen lamp or xenon projectors, for which the loss of light power due to the interception of the flow by the bar is not really detrimental .

The heat released by the light source and the solar rays entering the optical module via the lens causes the heating of the internal environment of the optical module and therefore the engine. This phenomenon of warming is defined in particular by a so-called environmental temperature. The motor is caused to dissipate a lot of power in operation which causes a significant self-heating of the engine. This phenomenon of self-heating is defined in particular by a so-called self-heating temperature.

The temperature reached by the engine, that is to say the sum of the environment and self-heating temperatures, is important, which may damage the plastic housing on which the engine is mounted.

It is known to overcome this disadvantage to install an electronic card with the engine in the optical module. The electronic card in fact reduces the intensity of the current flowing through the motor and therefore its power and reduces the heat that it must dissipate. However, such an installation is expensive and cumbersome. Another known solution is to choose the metal housing because of its resistance to high temperatures, but this material has the disadvantage of being heavy and expensive. The invention aims to remedy these drawbacks. For this purpose, the subject of the invention is a motor vehicle headlamp comprising a light source, a moving means and a movable optical element configured to be driven by said moving means and arranged to cut and / or reflect a light beam emitted by the source, characterized in that it comprises a radiator thermally connected to said moving means.

Thus, thanks to the radiator, it optimizes the diffusion of the heat of the moving means and we can do without both an electronic card and a case of expensive metal.

According to one aspect of the invention, the projector comprises a reflector, said light beam being reflected by the reflector before being cut and / or reflected by the movable optical element. According to an exemplary embodiment of the invention, the light source 30 comprises at least one light emitting diode, called LED diode.

According to one aspect of the invention, the radiator is configured to dissipate the heat generated by the LED or diodes. The invention thus makes it possible to use a single radiator to dissipate heat from the moving means and that from the light source.

Advantageously, said reflector has the shape of a half-ellipsoid portion extending above a plane of symmetry of said ellipsoid, said source being positioned on the axis of symmetry of the ellipsoid.

According to one embodiment, the radiator is positioned below the plane of symmetry of said ellipsoid. According to an exemplary embodiment of the invention, the radiator is positioned upstream of the movable optical element in the emission direction of said light beam. Advantageously, said radiator is located at least partly inside said ellipsoid. According to one embodiment of the invention, the radiator is located between a bottom of the reflector and said movable optical element. According to an exemplary embodiment of the invention, said projector comprises an optical lens, said radiator being positioned at least partly in a volume defined by the cylindrical extension along an optical axis of the lens of a peripheral contour of the lens. to a transverse plane passing through the bottom of the reflector. It will be understood that the radiator is situated, at least in part, within a volume defined by a second half-ellipsoid portion, symmetrical to the first half-ellipsoid portion and forming with it said portion of ellipsoid. Thus, in addition to improving the diffusion of heat, the invention makes it possible to position the radiator so that the projector of the invention does not take up more space than an elliptical projector without a radiator.

According to one aspect of the invention, the moving means is located in the same area of the projector as the radiator. The invention thus makes it possible to improve the cooling of the moving means by virtue of the radiator while optimizing the size of the spotlight. Advantageously, the moving means is located upstream of the mobile optical element in the direction of emission of said light beam. The moving means is thus protected from sunlight penetrating the projector through the lens. According to one embodiment of the invention, said moving means is located below the plane of symmetry of said ellipsoid.

According to one aspect of the invention, said moving means is located at least partly inside said ellipsoid. According to an exemplary embodiment of the invention, said moving means is located below said light source.

According to one aspect of the invention, the moving means is located between a bottom of the reflector and said movable optical element. Advantageously, said projector comprises an optical lens, said moving means being positioned at least partly in a volume defined by the extension of a peripheral contour of the lens to a bottom of the reflector parallel to an optical axis of the lens. The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following detailed explanatory description of an embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the accompanying schematic drawings. In these drawings: FIG. 1 is a schematic view of a semi-elliptical headlight according to one embodiment of the invention, in the high beam position, FIG. 2 is a schematic view of the headlight of FIG. , in the low beam position. - Figure 3 is a front view of an embodiment of the projector of the invention. Referring to FIGS. 1 and 2, there is shown a half-elliptical headlamp 1 of a motor vehicle comprising a reflector 12 having the shape of a first half-ellipsoid portion extending above a plane of symmetry of the vehicle. 'ellipsoid. The projector also comprises a light source S comprising a light-emitting diode, called LED diode, positioned inside the reflector. The light source here comprises a plurality of LEDs. A second half-ellipsoid portion 15 forming an ellipsoid portion with the first half-ellipsoid portion 14 is shown in dotted lines for purposes of understanding but does not represent a real physical element of the half-elliptical projector. The second half-ellipsoid portion 15 is symmetrical with respect to the first half-ellipsoid portion 14 along the plane of symmetry of the ellipsoid. The first half-ellipsoid portion is axially limited by a plane M perpendicular to the axis of symmetry of the ellipsoid and intersecting the ellipsoid. The light source S is positioned on an axis of symmetry x of the ellipsoid portion, at a first focus of the first half-ellipsoid portion, on the bottom side of the reflector 12, the light source emitting only on a solid angle of 27 steradians, or in section along a vertical plane passing through the optical axis, as shown in the figure, on a sector of 1800 directed upwards. This configuration is particularly well suited to a light source formed by LED light emitting diodes, which emit only on a solid angle of 27 steradians. The axis of symmetry x of the ellipsoid is a longitudinal axis of symmetry of the ellipsoid. The plane of symmetry of the ellipsoid contains the axis of symmetry x of the ellipsoid.

The luminous flux is directed, after reflection on the reflector 12 towards the second focus F of the ellipsoid and then towards a convergent lens 3 of the projector 1 located downstream of the reflector in the direction of emission of the luminous flux and whose purpose is to project the luminous flux on the road. Due to this emission on 27 steradians, the light beam is directed only toward the lower half of the lens 3. As can be seen in FIGS. 1 and 2, a mobile optical element 4 arranged to cut and / or reflect the light beam emitted by the source and reflected by the reflector is positioned at the second focus F. This is a mirror 4. In another embodiment of the invention not shown, it could be a cutoff bar. The reflecting surface of the mirror 4 is directed upwards so as to be able to intercept the luminous flux coming from the reflector 12. This mirror 4 is mobile about a horizontal axis so as to position its reflective surface, ie in a horizontal plane passing by or parallel to the axis of symmetry of the ellipsoid x, or, in a plane inclined forward, in a so-called retracted position. In FIG. 1, the mirror 4 is inclined relative to the horizontal plane and is positioned outside the luminous flux, thus passing all the rays in the direction of the lens 3. These traverse the lower part of the lens and are straightened upwards to illuminate the road for a long distance. We thus find ourselves in road position without loss of the light power emitted by the source S.

On the other hand, in FIG. 2, the mirror 4 is in a horizontal position and its longitudinal span is sufficient to intercept all the rays coming from the reflector 12. All these rays are reflected upwards by the mirror 4 and are redirected by the mirror to the upper part of the lens 3. At the exit of the lens, the light rays are returned towards the front, but with a downward inflection, which makes it possible to illuminate the road over a given distance. We then find ourselves in a code position, this time again, without losing the luminous power emitted by the source S. The shape of the beam to meet the requirements of the European code standards is given either by a particular shape of the lens 3 either by an axial shift of the focus of the lens relative to the second focus F of the ellipsoid, or finally by a combination of both. Practically, it should be noted that, whatever the position given to the mirror 4, the light source S remains on, the beam it emits being directed either substantially horizontally in the high beam position, or directed downwards in the fire position. crossing. The operation of the light source is thus improved, in particular when it is carried out by LEDs, since it does not pass through successive phases of ignition and extinguishing.

The projector 1 comprises at least one moving means 20 configured to make the movable optical element 4 mobile. The moving means 20 is, for example, an actuator, a solenoid, a coil or, as here, an electric motor. It comprises here a motor shaft at the end of which is positioned a pinion 21 which rotates the movable optical element 4 via a toothed sector 22. According to the invention, the projector 1 comprises a radiator 30 configured to dissipate the heat from the moving means 20.

As illustrated in Figure 3, the radiator comprises fins 31. The fins 31 extend parallel to each other and perpendicular to the axis of symmetry x of the ellipsoid. The radiator 30 is in contact with a frame of the moving means. It is designed to increase the exchange surface with air. The radiator allows the electric motor to admit in its turns a current density of up to 6A / mm2 and dissipate this current in an environment of 1300 to 160 ° C without exceeding the critical temperature of the turns, which is around 220 ° C. The radiator is located closest to the light source S and in particular upstream of the mobile optical element 4 in the direction 40 of emission of the light beam. The direction 40 of emission of the light beam is the direction by which it leaves the projector for the purpose of being projected on the road. The term "upstream" means that the radiator is located upstream of a plane P perpendicular to the axis of symmetry x of the ellipsoid, the plane P itself being located upstream of the mobile optical element 4 .

The radiator 30 is located below the plane of symmetry of the ellipsoid, for example at least partly inside the second half-ellipsoid portion shown in dotted line, that is to say inside the the ellipsoid portion. The radiator 30 is positioned at least partly in a cylindrical volume V resting along the optical axis of the lens 3, on the peripheral contour 18 of the lens 3, and extending as far as the bottom 13 of the reflector 12 as illustrated in FIGS. 1 and 2. The peripheral contour 18 of the lens 3 is, in particular circular.

The moving means 20 is advantageously located in the same zone of the headlamp as the radiator 30. The moving means 20 is for example located upstream of the mobile optical element 4 in the beam emission direction 40 luminous.

The moving means 20 is situated below the plane of symmetry of the ellipsoid, for example at least partly inside the second half-ellipsoid portion represented in dotted line, that is to say at inside the ellipsoid portion. The invention thus improves the cooling of the moving means while optimizing the size of the projector. In addition, since the light source emits a light beam only towards the first half-ellipsoid portion, the majority of the heat released by the light source is not directed towards the moving means. The moving means 20 being cooled by means of the radiator 30, it is thus possible to position the moving means 20 as close as possible to the light source, without the risk of it becoming too heated, and thus to improve the the size of the projector. The moving means 20 can therefore be located below said light source S, that is to say, it is crossed by a plane 0 perpendicular to the axis of symmetry x of the portion of ellipsoid passing by the light source S. The moving means 20 is positioned at least partly in said volume V.

The projector of the invention may also include several half-elliptical reflectors 12 as shown in Figure 3. These reflectors 12 are for example positioned next to each other. Positioning the moving means 20 upstream of the mobile optical element 4 is all the more advantageous in this embodiment because it allows to bring the lens or lenses 3 of each of the reflectors without being disturbed by the presence of the moving means. Advantageously, the projector comprises a single means of movement 20 for all the reflectors 12, arranged to make the moving optical elements 4 of each reflector mobile.

The projector comprises, for example, a support 19 on which the moving means 20 is mounted. The assembly can be done by snapping with a metal or plastic flange, welding, screwing to any other means of rigid assembly. The invention has been described with a combination of a plane mirror 4 and a lens 3 which reverses the light rays and gives the desired shape to the beam. It could equally well be achieved by a single beam reversal member, such as a mirror having a complex shape that returns the light beam forward giving it the desired shape. The transition from the high beam configuration to the low beam headlamps remains, in this case, provided by a displacement of the complex-shaped mirror, which is thus movable as is the plane mirror of the configuration described.

Claims (10)

REVENDICATIONS1. Projector (1) for a motor vehicle comprising a light source (S), a moving means (20) and a movable optical element (4) configured to be driven by said moving means (20) and arranged to cut and / or reflect a light beam emitted by the source (S), characterized in that it comprises a radiator (30) thermally connected to said moving means (20). 2. The projector of claim 1, wherein the projector (1) comprises a reflector (12), said light beam being reflected by the reflector (12) before being cut and / or reflected by the movable optical element (4). ). 3. Projector (1) according to claim 2, wherein said reflector (12) has the shape of a half-ellipsoid portion extending above a plane of symmetry of said ellipsoid, said source (S) being positioned on the axis of symmetry (x) of the ellipsoid. 4. Projector (1) according to claim 3, wherein the radiator (30) is positioned below the plane of symmetry of said ellipsoid. 5. Projector (1) according to claim 3 or 4, wherein said radiator (30) is located at least partly inside said ellipsoid. 6. Projector (1) according to one of claims 2 to 5, wherein the radiator (30) is located between a bottom (13) of the reflector (12) and said movable optical element (4). 7. Projector (1) according to claim 6, wherein said projector (1) comprises an optical lens (3), said radiator (30) being positioned at least partly in a volume (V) defined by the cylindrical extension according to an optical axis of the lens from a peripheral contour of the lens (3) to a transverse plane passing through a bottom (13) of the reflector (12). 8. Projector (1) according to any one of claims 1 to 7, wherein the light source (S) comprises at least one light emitting diode, said LED diode. 9. Projector (1) according to claim 8, wherein the radiator (30) is configured to dissipate the heat generated by the LED or diodes. 10. Projector (1) according to any one of the preceding claims, wherein the radiator (30) is positioned upstream of the movable optical element (4) in the direction of emission of said light beam.