EP1818602B1 - Motor vehicle headlight - Google Patents

Description

The invention generally relates to a motor vehicle headlamp comprising a light cache mechanism having at least two rotating light caps to respectively produce at least two different beams of light.

The documents DE102004025228 or FR2769071 show such projectors.

More particularly, the invention relates to a dual-function projector capable of producing light beams of code and route for the two traffic modes on the right and traffic on the left.

It is known to the inventive entity a dual function projector having two rotating light covers. Light caches provide a break in the code light beams for right and left traffic. The rotation of the covers and their angular positioning are obtained by means of a stepper motor control. This step-by-step control solution has disadvantages. A stepper motor is an actuator that remains relatively expensive and requires a suitable electronics, capable of generating the various impulse signals necessary for its control. In addition, the problem of the loss of pitch is likely to introduce inaccuracy in the angular positioning of the covers which requires the implementation of special provisions for periodically referencing the angular position of the axis of the stepper motor.

The main purpose of the invention is to provide a technical alternative to the use of a stepper motor in this type of projector.

The motor vehicle headlight according to the invention comprises a light-shielding mechanism having at least first and second rotatable light caps for respectively producing at least first and second different light beams.

• au moins un moyen d'indexage mécanique de la position de repos du mécanisme de cache,
• un actionneur apte à faire tourner lesdits premier et second caches de lumière selon deux sens de rotation.

The invention relates to a motor vehicle headlamp comprising a light-shielding mechanism having at least first and second rotating light caps for respectively producing at least different first and second beams of light, such that said cache mechanism also includes

• at least one means for mechanical indexing of the rest position of the cache mechanism,
• an actuator adapted to rotate said first and second light caps in two directions of rotation.

Preferably, the mechanical indexing means is chosen from a retractable abutment or other mechanical means of the type roller, blasting, spring, spring latch. The term "rest position" is understood to mean the position towards which the cover naturally returns, especially in the event of failure of its actuating means. This is usually a position where the emitted beam is a cut-off beam (as opposed to an unbroken beam of the road type).

Note that the term "projector" used in the context of this text relates in fact, unless otherwise specified, the unit optical module may be incorporated later in a complete projector with other modules.

According to the invention, the cover mechanism comprises at least a first stop defining at least a first angular position of stop in cache rotation, the stop being retractable and able to allow a crossing of the first angular position stop in cache rotation by at least one of the first and second light caches when lighting mode switching is controlled in the projector.

The light cache mechanism also includes at least one second fixed-type stopper defining at least one second cache-off stop angular position for producing a road-type light beam.

According to another feature, the light cache mechanism also includes resilient means for causing and maintaining a light shield in the first rotational stopping angular position when the actuator is inactive.

In a particular embodiment capable of providing code-cut light beams for right-hand traffic and left-hand traffic modes, the light cache mechanism includes first and second light caches having profiles. respective ones capable of producing the light beams with code-type cutoff; and the first retractable stopper determines angular positions of the first and second covers for the production of the code-cut light beams.

According to another feature, the light cache mechanism comprises two fixed second stops located on either side of the retractable stop with predetermined angular offsets and preferably symmetrically, and each fixed second stop determines a second respective rotational stop angular position for each of the first and second covers, for producing a road-type light beam.

According to a particular embodiment, the retractable stop is elastic and flexes to allow a crossing of the first angular position by a light cover when a mechanical torque greater than a maximum threshold torque is applied against the retractable stop. In addition, the actuator comprises a DC motor and an electronic control circuit capable of controlling the motor in two directions of rotation. The electronic control circuit is advantageously equipped with electric current limiting means for limiting an electric current flowing in the motor when the latter is in a locked torque operating state.

According to another aspect, the invention also relates to a motor vehicle equipped with at least one projector (the unitary optical module or the complete projector) according to the invention.

• variante a : un code trafic à droite et un code trafic à gauche
• variante b : un code (soit trafic à droite soit trafic à gauche), et un faisceau conforme aux nouvelles réglementations dites AFS « Advanced Frontlighting Systems). Ce faisceau « AFS » est notamment choisi parmi le faisceau appelé faisceau autoroute (« motorway » en anglais), ou un faisceau de mauvais temps (« adverse weather » en anglais).
• Variante c : un code (ou un faisceau AFS) et un faisceau à coupure plate de type anti-brouillard.

According to embodiments of an optical module according to the invention, the first and second cut-off beams obtained with the cache mechanism are

• variant a: a traffic code on the right and a traffic code on the left
• variant b: a code (either traffic on the right or traffic on the left), and a bundle compliant with the new regulations called AFS "Advanced Frontlighting Systems". This beam "AFS" is chosen in particular from the beam called motorway beam ("motorway" in English), or a beam of bad weather ("adverse weather" in English).
• Variant c: a code (or AFS beam) and a fog-type flat beam.

For each of these variants, a third beam of the road type is also proposed, so as to obtain a tri-function optical module, which will correspond to a position of the mechanism of caches that it does not hide the rays emitted by the source directly or after reflection on the associated reflector.

• les Figs.1A à 1C montrent de manière simplifiée la structure générale d'un projecteur selon l'invention dans différents états de fonctionnement;
• la Fig.2 est un chronogramme de principe de la commande d'un moteur à courant continu inclus dans un mécanisme de cache du projecteur; et
• les Figs.3A et 3B montrent le mécanisme de cache dans deux états correspondant respectivement à la production d'un faisceau de code pour trafic à droite et d'un faisceau de code pour trafic à gauche.

Other aspects and advantages of the present invention will appear more clearly on reading the description of a particular embodiment which follows, this description being given by way of nonlimiting example and with reference to the appended drawings. , wherein :

• the Figs.1A to 1C show in a simplified manner the general structure of a projector according to the invention in different operating states;
• the Fig.2 is a timing diagram of the control of a DC motor included in a projector cover mechanism; and
• the Figs.3A and 3B show the cache mechanism in two states corresponding respectively to the production of a right-hand traffic code bundle and a left-traffic traffic code bundle.

With reference to Figs.1A to 1B and 2 , a particular embodiment of the invention is now described in the form of a dual-function code / road searchlight, identified globally 1, capable of automatically switching between a traffic flow mode on the right and a traffic mode. Traffic left.

The projector 1 described here is intentionally represented in a simplified manner to Figs.1A to 1B to facilitate the understanding of the invention.

The projector 1 is of elliptical type and is designed to emit a beam of illumination light along an optical axis AA passing through foci F1 and F2. The projector 1 essentially comprises a light source 10 located at a focus F1 of the headlamp 1, an elliptical reflector 11, a lens 12 and a light cache mechanism 13.

The light source 10, the reflector 11 and the lens 12 are known elements, similar to those usually included in such a lighting projector for a motor vehicle. For this reason, these elements 10, 11 and 12 will not be detailed here.

The cover mechanism 13 is located substantially at the focal point F2 of the projector 1.

As shown in more detail in Figs.3A and 3B , the cover mechanism 13 essentially comprises two integrally formed covers 130D and 130G 130, a motor actuator 131, a return spring 132 and three stops 133, 133D and 133G. In this particular embodiment, the stops 133D and 133G are located on either side of the stop 133, with determined angular offsets, preferably symmetrically.

The cache 130D is provided with a profile able to introduce a code-like break in the traffic flow mode on the right TD. Cache 130G is provided with a profile capable of introducing a code-like break in the left traffic traffic mode TG.

The motor actuator 131 controls rotations of the cover piece 130 around an axis PP perpendicular to the optical axis AA ( Fig.1 ) of the projector 1.

The actuator 131 essentially comprises an electric motor 1310 and an electronic control circuit 1311. The motor 1310 is preferably a DC motor. The electronic circuit 1311 controls the operation of the motor 1310 as a function of two input signals, namely, a C / R code / route mode control signal and a right / traffic traffic mode control signal. left TD / TG.

The circuit 1311 is powered by a DC voltage V and outputs a control voltage VM whose polarity is variable so as to control the direction of rotation of the motor 1310.

The functions of the stops 133, 133D and 133G as well as the operation of the motor actuator 131 will now be described in more detail.

The Figs.1A, 1B and 3A shows the headlamp 1 in states corresponding to the right traffic traffic mode TD.

In the Figs.1A and 3A , the projector 1 is in the code illumination mode, in TD traffic. This state corresponds to the time interval t1 shown in FIG. Fig.2 . The control voltage VM is at 0 volts and the motor 1310 then exerts no torque on the cover piece 130. A return torque Cr is instead exerted by the spring 132 in the clockwise direction SH of such way that the cover 130D is held in abutment against the stop 133.

According to the invention, the stop 133 is of the retractable type. In this particular embodiment, a resilience property is imparted to the abutment 133 in such a manner as to make it retractable. Of course, the function of the stop 133 can be carried out so different by the skilled person. For example, in the form of a sliding stop actuated by an electromagnet.

In this particular embodiment, the stop 133 no longer fulfills its function of stopping rotation of the cover piece 130 when the torque Cc applied to the cover piece 130 is greater than a maximum threshold threshold Cm of determined value. Thus, when the torque Cc applied to the cover piece 130 is greater than Cm, the mechanical force applied to the stop 133 by the cover 130D or 130G resting against it causes the stopper 133 to bend by elasticity. The bending of the stop 133 is then sufficient to release the piece of cover 130 and allow a continuation of the rotation thereof after crossing the stop 133.

In the state corresponding to the Fig.1A , the restoring torque Cr due to the spring 132 is less than the maximum threshold torque Cm and the stop 133 then fully fulfills its function of stopping the rotation of the cover 130, by contacting the cover 130D against it (cf. 3A ).

The Fig.1B shows the headlamp 1 in the road lighting mode, still in TD traffic. This state corresponds to the time interval t2 shown in FIG. Fig.2 .

The control voltage VM then has a value -Vm capable of producing a rotation torque of the motor 1310 in the inverse clockwise direction SHi. When the cover 130G comes into contact with the stop 133D, the rotation of the cover piece 130 stops. The voltage VM = -Vm is maintained in order to oppose the return torque Cr exerted by the spring 132 and to keep the cache piece 130 in the state shown in FIG. Fig.1B .

In this particular embodiment of the invention, in order to avoid a deterioration of the motor 1310 when the latter is in a locked torque state, a limitation of the current supplied to the motor is provided. The locked torque state occurs when the cover piece 130 comes into contact with the stop 133D in the TD traffic mode or the stop 133G in the TG traffic mode.

This limitation of the motor current 1310 is provided by the control circuit 1311. Those skilled in the art will usefully refer to the patent application FR-2854941 B of the applicant for details on how to achieve such a motor current limitation 1310.

With reference to the Fig.2 , the time interval t3 corresponds to the switching of the projector 1 to the left traffic mode TG.

During the time interval t3, the control voltage VM is reversed in polarity and becomes VM = + Vm. The motor 1310 then provides a mechanical torque in the clockwise direction SH which is added to the torque Cr exerted by the spring. The torque Cc applied to the cover piece 130 then takes a value which is greater than the torque Cm such that the retractable stop 133 flexes sufficiently and no longer impedes the rotation of the cover piece 130 which comes into the state shown in the Fig.1C . Of course, in order to have a correct operation of this switching to the traffic mode TG, the voltage VM must retain the value + Vm for a time sufficient to allow crossing of the stop 133 by the two screens 130D and 130G, as shown in FIG. the Fig.1C . After crossing the stop 133 by the cover 130G, the voltage VM can be brought back to 0 Volt to come into the code illumination mode in TG traffic or maintained at + Vm to come in the road lighting mode in TG traffic.

To the Figs.1C and 3B , the projector 1 is shown in the code illumination mode, in TG traffic. This state corresponds to the time interval t4 shown in FIG. Fig.2 . The control voltage VM is at 0 volts and the motor 1310 then exerts no torque on the cover piece 130. The restoring torque Cr is instead exerted by the spring 132 in the reverse clockwise direction SHi of such that the cover 130G is held in abutment against the stop 133, more precisely against a contact face of the stop 133 which is opposite to that serving to support the cache 130D in the TD traffic mode.

The abutment 133 operates here in the same manner as described above with respect to the TD traffic flow mode and is also retractable for switching from the traffic flow mode TG to the traffic circulation mode TD.

In the state corresponding to the Fig.1C , the return torque Cr due to the spring 132 is therefore less than the maximum threshold torque Cm and the stop 133 fully fulfills its function of stopping the rotation of the cover piece 130, by contacting the cover 130G against the stop 133 (cf. . 3B ).

The Fig.1d shows the headlamp 1 in road lighting mode, always in TG traffic. This state corresponds to the time interval t5 shown in FIG. Fig.2 .

The control voltage VM then has a value + Vm able to produce a rotation torque of the motor 1310 in the clockwise direction SH. When the cache 130D comes into contact against the stop 133G, the rotation of the cache piece 130 is interrupted. The voltage VM = + Vm is maintained in order to oppose the return torque Cr exerted by the spring 132 and to keep the cache piece 130 in the state shown in FIG. Fig.1d . The limitation of the current of the motor 1310 is here also provided to prevent deterioration thereof in locked torque.

The time interval t6 shown at Fig.2 corresponds to the switching of the projector 1 to traffic flow right TD, to return to the state of the time interval t1 or t2. The operation of this switching is similar to that described above for switching from TD mode to TG mode and will not be detailed here.

As is clear from the foregoing description of this first embodiment of the invention, the stops 133, 133D and 133G determine different angular positions of rotation stop caches.

The retractable stop 133 with its opposite contact faces determine two angular positions, one for the 130D cover and one for the 130D cover, these angular positions corresponding to TD traffic mode code illumination and TG traffic mode code illumination.

The fixed stops 133D and 133G determine two angular road illumination positions for the 130D and 130G caches, one for the TD traffic mode and the other for the TG traffic mode.

Of course, the present invention is not limited to the details of the particular embodiment described here by way of example, but extends instead to modifications within the scope of the art without departing from the scope of the invention.

Thus, the skilled person may not use a DC motor for the rotation of the cover piece 130 but use for example other types of actuator such as a stepper motor or an electromagnet. In the case of the use of a stepper motor, the presence of stops in accordance with the invention will bring a greater robustness of the angular positioning of the piece of cache, for example by allowing referencing in case of loss of step .

Claims (12)

1. Headlight for a motor vehicle, comprising a light shield mechanism (13, 131) with at least first and second rotary light shields (130D, 130G) in order to produce respectively at least first and second different light beams, the said shield mechanism also comprising:

   - at least one means for mechanical indexing of the position of rest of the shield mechanism;

   - an actuator (131) which can make the said first and second light shields (130D, 130G) rotate according to two directions of rotation,

   the headlight being characterised in that it comprises at least a first stop (133) which determines at least a first angular position of stoppage in rotation of the shield, the said stop (133) being retractable and able to permit clearance of the said first angular position of stoppage in rotation of the shield by at least one of the said first and second light shields (130D, 130G) when lighting mode switching (C/R, TG/TD) is commanded in the headlight (1),
   and in that it can also provide a light beam of the high-beam type, the said light shield mechanism (13, 131) also comprising at least one second stop of a fixed type (133D, 133G) which determines at least a second angular position of stoppage of rotation of the shield, for the production of a light beam of the high-beam type.
2. Headlight for a motor vehicle according to the preceding claim, characterised in that the mechanical indexing means is selected from amongst a retractable stop or another mechanical means of the roller, ball, spring, or spring lock type.
3. Headlight according to one of the preceding claims, characterised in that the said light shield mechanism (13, 131) also comprises resilient means (132) to bring one of the said light shields (130D, 130G) into the said first angular position of stoppage of rotation, and retain it there, when the said actuator (131) is inactive.
4. Headlight according to one of the preceding claims, which can provide light beams with cut-off of the low-beam type for traffic circulation modes on the right and on the left, characterised in that the said first and second light shields (130D, 130G) have respective profiles which can produce the said light beams with cut-off of the low-beam type; and
   the said first retractable stop (133) determines angular positions of the said first and second shields (130D, 130G) for the production of the said light beams with cut-off of the low-beam type.
5. Headlight according to one of the preceding claims, characterised in that the said first and second light shields (130D, 130G) have respective profiles which can produce respectively a first beam with low-beam cut-off, and a second beam with a different cut-off, in particular of the low-beam, motorway or anti-fog type.
6. Headlight according to one of the preceding claims 1 to 4, characterised in that the said first and second light shields (130D, 130G) have respective profiles which can produce respectively a first beam with low-beam cut-off for traffic on the right, and a second beam with low-beam cut-off for traffic on the left.
7. Headlight according to one of the preceding claims, which can provide a third light beam without cut-off, in particular of the high-beam type.
8. Headlight according to one of the preceding claims, comprising two second stops of a fixed type (133D, 133G) which are situated on both sides of the said retractable. (133), with predetermined angular offsettings, and preferably symmetrically, characterised in that each second stop of a fixed type (133D, 133G) determines a second respective angular position of stoppage of rotation for each of the said first and second shields (130D, 130G), for the production of a light beam of the high-beam type.
9. Headlight according to any one of claims 1 to 8, characterised in that the said retractable stop (133) is resilient, and bends in order to permit clearance of the said first angular position by a light shield (130D, 130G), when a mechanical torque (Cc) which is greater than a maximum threshold torque (Cm) is applied against the said retractable stop (133).
10. Headlight according to any one of claims 1 to 9, characterised in that the said actuator (131) comprises a direct current motor (1310) and an electronic control circuit (1311) which can control the said motor (1310) according to two directions of rotation.
11. Headlight according to claim 10, characterised in that the said electronic control circuit (1311) comprises electric current limitation means, in order to limit an electric current which circulates in the said motor (1310) when the latter is in an operating state with torque blocked.
12. Headlight according to any one of claims 1 to 11, characterised in that it comprises a reflector of an elliptical type (11).

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