Optical Casing Having A Reduced Weight For A Motor Vehicle, Optical Module, And Vehicle Body Part

The invention relates to an optical casing for a motor vehicle, including a top portion for receiving a glass panel, a bottom portion, and an assembly of lateral elements for connecting the top portion to the bottom portion, characterized in that the top portion forms a frame that is provided with a joint along the entire periphery thereof, said joint being designed to rest against a sealing surface of a housing in the vehicle.

FIELD OF THE INVENTION

This invention relates to the technical field of optical devices for motor vehicles. In particular, the invention relates to an optical casing to reduce the weight of the optical device.

BACKGROUND OF THE INVENTION

An optical casing is a casing adapted to receive a functional assembly, such as electrical, electronic and optical means, in order to fulfil the lighting function of a vehicle. Such an optical casing is closed by a transparent glass panel to form a sealed optical module.

Such an optical casing is assembled in a housing of a motor vehicle part (bumper, rear door, fender) provided for this purpose, by means of attachment points, and by fitting a seal between the back of the optical casing (opposite the glass panel) and the part (lining or skin in the case of a tailgate).

One disadvantage of this solution is that in order to access the functional assembly, for possible repairs, the optical casing must be removed completely from its housing.

Furthermore, with this solution, two groups of solid walls in parallel are required: the walls forming the casing of the optical module and the walls of the housing to which the optical module is attached. This leads to higher manufacturing costs (use of additional material) and makes the vehicle unnecessarily heavier.

To overcome this problem, an optical module is also known, whose casing is molded with the housing wall to which the optical module is attached (e.g. the lining of a tailgate).

However, with such a solution, the optical module which is in this case “integrated” cannot be removed, resulting in limited accessibility to the functional assembly.

SUMMARY OF THE INVENTION

The main objective of this invention is to overcome the above-mentioned disadvantages by providing an optical casing whose walls can be perforated in order to reduce the weight of the casing as well as to reduce the weight of the housing for which it is intended.

The invention achieves this objective by transferring the sealing area to the top portion of the optical casing, i.e. just under the portion designed for receiving the glass panel.

The invention thus relates to an optical casing for a motor vehicle, comprising a top portion for receiving a glass panel, a bottom portion, and an assembly of lateral elements for connecting the top portion to the bottom portion. The top portion forms a frame that is provided with a seal along the entire periphery thereof, the seal being designed to rest against a sealing surface of a housing in the vehicle.

Such an optical module reduces the quantity of plastic material used to manufacture the elements required for the lighting function on board a motor vehicle. This reduction of material through “strap” connections between the bottom and top portions is allowed both on the optical module and on the housing into which it will be fitted (on a skin or tailgate lining for example, or on a bumper skin).

Moreover, this solution allows greater accessibility via the various openings.

The device may further comprise one or more of the following characteristics, taken alone or in combination:the top portion comprises on its periphery a groove into which the seal is inserted;the opening of the groove is oriented towards the outside of the optical casing;the opening of the groove is oriented towards the bottom portion of the optical casing;the bottom portion forms a perforated wall;the bottom portion forms a frame;the lateral elements form perforated walls.

The invention also relates to an optical module comprising an optical casing according to the invention, a glass panel closing said optical casing, and an assembly of functional elements mounted on the bottom portion and/or on the lateral connection elements.

The invention also relates to a motor vehicle bodywork part comprising a housing for optical module, and comprising an optical casing according to the invention, attached inside said housing, the seal resting against a sealing surface of the housing.

According to the invention, the housing may comprise a shoulder forming the sealing surface and against which the seal in the groove of the optical casing rests sealably. Preferably, the housing comprises perforated walls.

Finally, according to a particular embodiment, at least one of the perforated walls of the housing coincides with at least one of the perforated walls of the optical casing to provide access inside the optical casing.

DETAILED DESCRIPTION OF THE INVENTION

We now refer toFIG. 1which illustrates an example of motor vehicle part1, a tailgate, comprising a housing50adapted to receive an optical casing10according to the invention.

FIGS. 2A and 2Billustrate in more detail a particular embodiment of the optical casing10for a motor vehicle according to the invention.

FIG. 2Ashows in three dimensions such an optical casing10, whileFIG. 2Bis a cross-section C-C of a portion of this optical casing10with its glass panel30and its housing50.

This optical casing10is adapted to receive a functional assembly20(electrical, electronic and optical means) and to be closed by a glass panel30, so as to form an optical module40.

Such an optical module40is designed to be attached in the housing50of the motor vehicle, provided for this purpose.

The optical casing10comprises a top portion60designed for receiving a glass panel: this portion is therefore designed to be positioned/oriented towards the outside of the vehicle. The optical casing10also comprises a bottom portion70designed to be positioned/oriented towards the inside of the vehicle, and an assembly of lateral elements80for connecting, preferably discontinuously (i.e. having at least one perforation), the top portion60to the bottom portion70.

The top portion60forms a frame that is provided with a seal90extending along the entire periphery of the frame60. This seal90is designed to rest against a sealing surface100of a housing50in the motor vehicle.

The seal90can be attached to the frame60in any way known by specialists.

According to an embodiment described onFIGS. 2A and 2B, the frame60is provided on its periphery with a groove110into which the seal90is inserted. Another structure for receiving the seal90could be used without leaving the scope of the invention, for example a rib onto which the seal having a slot provided for this purpose is pressed.

The opening of the groove110is oriented towards the bearing surface of the housing50against which the seal90is designed to rest so as to form a seal inside the housing50, i.e. between the outside of the vehicle and the inside of the optical module40.

Thus, according to an embodiment (FIGS. 2A, 2B, 3A and 5B), the opening of the groove110is oriented towards the outside of the optical casing10, and according to another example (FIGS. 3B and 5C), the opening of the groove110is oriented towards the bottom portion of the optical casing10.

According to a preferred embodiment, the bottom portion70forms a perforated wall, comprising one or more openings120. Since the inside of the optical casing10is sealed with the glass panel30and the seal90, the quantity of material used to manufacture the optical casing10can be limited. Thus, the area of the bottom portion can be minimized. For example, the bottom portion70can be designed like a simple frame, as illustrated onFIGS. 2A and 2B.

The only constraint on the assembly, consisting of the bottom portion70and the lateral elements80, is to be able to attach a functional assembly (electrical, electronic and optical means) thereon, as illustrated onFIG. 3A.

Advantageously, the optical casing10is manufactured using a lightweight material adapted to support the various lighting functions (lighting, reflector, mask, etc.). For example, plastic materials and metal materials can be used alone or in combination. For example, the reflector can be made of polypropylene (PP) coated with a metallization layer, the glass panel30can be made of polymethylmetacrylate (PMMA), the casing can be made of polypropylene (PP) for example.

The material used for the optical casing10may advantageously be selected to help dissipate the heat generated by the electronic components inside the optical module40. Aluminum parts are used to dissipate the heat generated by LED (Light Emitting Diode) lighting. Due to the openings in the casing10according to the invention, cooling parts of smaller size can be used, while nevertheless being capable of dissipating the heat given off by the lighting.

Optical Module

The invention also relates to an optical module40(FIG. 3A) comprising an optical casing10according to the invention, a glass panel30closing the optical casing10, and an assembly of functional elements20(bulb or LED22, mirror24, printed circuit board (PCB)26) mounted on the lower portion70and/or on the lateral connection elements80.

Motor Vehicle Part

Such an optical module40is designed to be attached in a motor vehicle housing50, provided for this purpose.

Thus, the invention also relates to a motor vehicle bodywork part1comprising a housing50for optical module40, and comprising an optical casing10according to the invention, attached inside the housing50, the seal90resting against a sealing surface of the housing50.

The housing50comprises a top portion51(towards the outside of the vehicle) and a bottom portion52(towards the inside of the vehicle) designed for receiving the bottom portion70of the optical module, and an assembly of lateral elements53for connecting the top portion51to the bottom portion52.

As illustrated onFIG. 4, the optical casing10is attached to housing50by attachment means. It can thus be screwed, clipped or attached by any other means in order to compress or stress the seal90.

FIG. 4illustrates an example according to which the bottom portion70of the optical casing10is a frame, having holes75distributed around the perimeter of the frame70. The housing50comprises bearing and attachment areas55designed to maintain the optical casing10in position. As illustrated onFIG. 4, an element projecting towards the inside of the housing50could be used, each projecting element having a hole opposite the holes75when the optical casing10is inserted in position in the housing50. The optical casing10now simply has to be attached to the housing50, by means of screw, nut, rivet, etc.

According to an embodiment, illustrated onFIGS. 4 and 5A to 5C, the housing50comprises perforated walls. Since the inside of the optical casing10is sealed by the glass panel30and the seal90, the quantity of material used to manufacture the housing50can be limited. Thus, the areas of the bottom portion52and the lateral walls53can be minimized. For example, the bottom portion52can be designed like a simple frame. The perforations in the housing50also improve the heat dissipation of the optical module.

FIG. 5Cshows an alternative embodiment to that shown onFIG. 5B, According to this embodiment, the top portion51of the housing50comprises a shoulder56, forming the sealing surface, and against which the seal90in the groove110of the optical casing10rests sealably. The advantage of a such an embodiment is that the force required to position the optical casing10in the housing50maintains the seal90in the groove110and improves the compression of the seal necessary for it to perform its sealing function.

Consequently, tightening the attachment means, such as screws, in the holes in order to attach the casing10in the housing50, crushes the seal90on the shoulder. The sealing can therefore be precisely adjusted.

Thus, according to an embodiment example (FIG. 5B), the opening of the groove110is oriented towards the outside of the optical casing10, and according to another example (FIG. 5C), the opening of the groove110is oriented towards the bottom portion of the optical casing10.

The openings, made possible due to the sealing system in the top portion of the casing10, at the bottom portion70, the lateral elements80and the walls of the housing50, reduce the quantity of material used to manufacture the optical casing10and the housing50, and therefore reduce the weight of the vehicle. These openings also allow easy maintenance, since the elements of the functional assembly20can advantageously be accessed through the openings.

For maintenance purposes, the openings120of the optical casing10are preferably located opposite the openings57of the housing. The defective element of the functional assembly20can therefore be removed, without removing the optical casing10, and therefore, without having to touch the sealing area. For example, at least one of the perforated walls of the housing50coincides with at least one of the perforated walls of the optical casing10to provide access to the bulb22in order to replace it.

As illustrated onFIG. 1, the part may be a motor vehicle tailgate.

Finally, the various elements, optical casing10, optical module40and motor vehicle part1, are preferably made of plastic material. The use of this material allows various perforations and complex forms to be made, in a single manufacturing step.

The invention is not limited to the embodiments described and other embodiments will be clearly apparent to those skilled in the art. The motor vehicle part may in particular be a bumper or any other outer bodywork part comprising a dedicated housing.