FR3121286A1 - Body part with an internal antenna - Google Patents

Abstract

The invention relates to a bodywork part (10) comprising a volume (20) delimited by walls (30) made of plastic material, characterized in that the volume (20) comprises a wall (40) on which at least one wire conductor (50) is deposited so as to form a wave transmission/reception means of an antenna. Figure for abstract: Figure 4

Description

Body part with an internal antenna

The invention relates to the field of motor vehicles, and more particularly to the field of antennas, installed on such vehicles, for the reception of electromagnetic waves.

A conventional antenna is a device comprising at least one conductive element used to react to an electromagnetic field, by creating an alternating current in the antenna and a voltage between its terminals. The conductive elements used in conventional antennas are typically made from solid conductive materials.

It is known to position one or more antennas on the roof of a vehicle, for example inside a device having the shape of a shark fin.

However, such a device offers resistance to the wind which generates disturbances in the flow of air around the vehicle, generating noise and slightly increasing fuel consumption.

It is also known to integrate radio aerials (AM/FM/DAB) on the rear window of the vehicle or under the spoiler, on films or even in a wired form.

But such solutions have the following drawbacks:

• the geometry of the antenna depends on the support part;
• the film is fragile;
• the film is sensitive to the vibrations of the vehicle which alters the quality of the signal.

Furthermore, car body parts are increasingly made of plastic, and it is therefore not possible to take advantage of the conductive elements of the vehicle to capture electromagnetic waves.

The object of the invention is in particular to remedy these drawbacks by providing a body part incorporating an antenna in a compact plastic environment while obtaining a satisfactory radio signal.

To this end, the subject of the invention is a body part comprising a volume delimited by walls made of plastic material, in which the volume comprises a wall on which at least one conductive wire is deposited so as to form a transmission means /reception of waves from an antenna.

The antenna thus produced is robust and offers low sensitivity to vehicle vibrations. Thanks to this antenna integration, the body part can be positioned at a sufficient height above the ground, offering good reception quality.

The use of a wall of an internal volume allows the antenna to have sufficient dimensions for the reception of the vertical and horizontal components of the signal.

The fact of integrating the antenna in a plastic environment makes it possible to move the antenna away from metal parts of the vehicle which disturb the radio signal.

Most of the current antennas made by screen printing on the back glass or positioned in a plastic environment require a radio frequency ground plane (a flat metal surface forming part of the antenna) in order to improve the low quality of the received signal due to low wire length. Thanks to the new antenna integration according to the invention, it is possible to use antenna wires having a suitable length (sufficiently long) to produce a pattern making it possible to receive the signal while avoiding the use of a ground plane.

Finally, this integration into compact spaces preserves the exterior appearance of the bodywork.

According to other optional characteristics of the part taken alone or in combination:

• the wall provided with the conductive thread is one of said walls delimiting the volume;
• the bodywork part includes a plastic plate added inside the volume, said plate including the wall provided with the conductive wire;
• the wall provided with the conductive wire has ribs, the conductive wire being at least partially deposited on said ribs;
• the conductive thread is deposited by ultrasound on the wall, or the conductive thread is attached by clipping onto the wall in notches or flexible elements;
• the bodywork part comprises a first part forming a lining and a second part forming a skin, the two parts being fixed to each other so as to provide a space between the two parts forming the volume;
• the body part constitutes a motor vehicle roof, or a motor vehicle tailgate, or a motor vehicle spoiler.

Brief description of figures

The invention will be better understood on reading the following description given solely by way of example and made with reference to the appended drawings in which:

there illustrates an example of a body part according to the invention.

there illustrates a first embodiment of a body part according to the invention.

there illustrates a second embodiment of a body part according to the invention.

there illustrates a third embodiment of a body part according to the invention.

there illustrates a variant of the third embodiment of the , comprising an amplifier.

there illustrates another example of a body part according to the invention.

detailed description

There illustrates a body part 10 comprising an internal volume 20. The volume 20 is delimited by walls 30 made of plastic material. The volume 20 constitutes an available space within the vehicle, forming a box capable of favoring the reception of a radio signal.

According to the example illustrated in this figure, it is a bodywork part comprising:

• a first part 12 forming a lining;
• a second part 14 forming a skin.

The two parts 12 and 14 are fixed to each other so as to leave a space between them. This space forms volume 20.

Such a body part 10 can for example be a motor vehicle roof, a motor vehicle tailgate ( ), or a motor vehicle spoiler ( ).

But the invention is not limited to this type of volume, and any body part comprising an internal volume falls within the scope of the present invention.

According to the invention, the volume 20 comprises a wall 40 on which at least one conductive wire 50 is deposited so as to form a means for transmitting/receiving waves from an antenna. It is therefore more advantageous to place the conductive wire 50 of the antenna within a volume located high up in the vehicle.

Conductive wire 50 is deposited forming a pattern specific to the type of antenna. The antenna can, for example, be of the type:

• AM antenna: allows you to receive amplitude-modulated sound broadcasting;
• FM1/FM2 antennas: used to receive frequency modulation sound broadcasting; the FM2 antenna is active within a diversity system (multi-antenna);
• DAB antenna (T-DMB Terrestrial Digital Mobile Broadcasting): digital radio allows you to receive radio broadcasts.

For each type of antenna, the length and the pattern formed by the conducting wire 50 are defined. The other parameters of the conductive wire 50, such as its composition or its diameter, can remain identical.

Preferably the wall 40 comprises several wires 50, each wire having a length, a material and describing a particular pattern corresponding to a type of antenna. Thus, the wall 40 comprises a plurality of antennas. Figures 4 and 5 illustrate an example in which the wall 40 comprises four different types of antenna: the wall comprises four wires 50 of different lengths, and the wires 50 form different patterns, specific to their function.

According to exemplary embodiments, the conducting wire 50 has a length comprised between 20 and 40cm, preferably approximately 30cm, and it has a diameter comprised between 150 μm and 300 μm, preferably approximately 220 μm. Conductor wire 50 is preferably a copper or, alternatively, aluminum conductor wire.

Preferably, the conductive wire 50 is connected to one or more amplifiers 90. According to a variant embodiment, the bodywork part 10, for example the roof, comprises openings in order to cool the amplifiers 90 by air.

Conductive wire 50 can be attached to wall 40 in different ways:

1. The conductive wire 50 is fixed on a film, and the film is adhesive-coated on the wall 40.
2. The conductive wire 50 is deposited by ultrasound on the wall 40. It is possible, for example, to use a sonotrode, making it possible to very locally melt the plastic material of the wall 40, and to push the conductive wire 50 into this molten plastic material. Such a process has the advantage of being less fragile and less sensitive to vehicle vibrations compared to film.
3. The conductive wire 50 is attached by insertion into the wall 40. According to this variant, the wall 40 has notches made by molding, into which the conductive wire 50 is inserted.
4. The conductive wire 50 is attached by clipping onto the wall 40. According to this variant, the wall 40 comprises flexible elements, such as clips, also made by molding.

These methods of depositing the conductive wire 50 on the wall 40 can be combined. For example, when the conductive wire 50 is introduced into a notch, hot spots can be produced locally in order to melt the plastic material which will crimp the conductive wire 50 while hardening (ultrasound riveting, etc.).

We will now describe three embodiments of the invention.

First embodiment ( )

According to this first embodiment, and as illustrated in the , the wall 40 provided with the conductive wire 50 is one of the walls 30 delimiting the volume 20.

Preferably one chooses from the walls 30 delimiting the volume 20, a wall having an angle with the horizontal, so as to improve the reception of the waves by the antenna.

Second embodiment ( )

According to this second embodiment, and as illustrated in the , the wall 40 provided with the conductive wire 50 is one of the walls 30 delimiting the volume 20 comprising ribs 70, forming a network of structural ribs.

It is common for plastic body parts to have a network of structural ribs. The purpose of these ribs is to stiffen part of the part intended to be visible from outside the vehicle. For example, a rear spoiler, fixed on the roof or on the tailgate of a vehicle, comprises a lining constituting the structural part of the spoiler and on which is fixed an external skin. The liner usually has a network of ribs to perform its structural function.

As illustrated by , according to this second embodiment, the conducting wire 50 is at least partially deposited on these ribs 70.

Conductive wire 50 is deposited forming a pattern specific to the antenna. To respect this pattern, the conductive thread 50 can follow the crests of the ribs, or on the contrary, the conductive thread 50 can pass between two crests of the ribs, or certain segments of the conductive thread 50 can follow the crests and other segments can form a bridge from one rib to another.

As illustrated on the , preferably, the conductive wire 50 is fixed to the ribs by means of notches. Thus the conductive thread is clipped punctually to the rib. This clipping in the notch can advantageously be accompanied by partial melting during the installation of the conductive wire in order to improve the maintenance of the film.

The segments of the conductive wire 50 following the crest line of a rib, can be fixed by means of welding with sonotrode. The sonotrode can be guided by resting on the sides of the rib.

According to a variant, the bodywork part comprises additional ribs in order to serve as a support for the conductive wire 50. There is therefore a first network of structural ribs, the primary function of which is to ensure the mechanical strength of the bodywork part 10, and there is a second network of ribs whose primary function is to provide support for the conductive wire 50 in order to obtain the desired pattern depending on the type of antenna.

Third embodiment (figure s 4 and 5 )

According to this third embodiment, and as illustrated in the , the body part 10 comprises a support plate 60 made of plastic material attached to the interior of the volume 20. The support plate 60 comprises the wall 40 provided with the conductive wire 50.

The support plate 60 can be made of polycarbonate (PC), polypropylene (PP) or any type of plastic material. The plastic material may include talc in order to provide stiffness to the support plate 60.

According to an exemplary embodiment, the support plate 60 is made of polypropylene (PP) loaded with 10% talc, and has the following characteristics:

• length between 250mm and 850mm, preferably substantially equal to 430mm;
• width between 50mm and 200mm, preferably substantially equal to 100mm;
• thickness between 1mm and 5mm, preferably substantially equal to 2mm.
• volume between 12.5 cm ³ and 850 cm ³ , preferably substantially equal to 81.91 cm ³ ;
• Projected surface between 125cm ² and 1700cm ² , preferably substantially equal to 409.60cm ² ; And
• Mass between 20g and 120g, preferably substantially equal to 80g.

The support plate 60 is fixed inside the volume 20 by any means: clipping, screwing, riveting, gluing, gluing, etc. Preferably, the support plate 60 is positioned in the volume 20 so as to present an angle with the 'horizontal, in order to improve the reception of the waves by the antenna. Indeed, such an angle allows the antenna, or each of the antennas when there are several wires 50, to have a component in the vertical plane, and thus to optimize the reception of the radio signal. Furthermore, this angle can be chosen so as to favor the repeatability of its assembly by the operator on the bodywork part.

Advantageously, the angle is preferably chosen between 25° and 40°.

According to an exemplary embodiment, the support plate 60 comprises means for adjusting its inclination with respect to the horizontal plane. For example, it may be tenons, removable or not, of different lengths distributed on one face, preferably at the angles, of the support plate 60.

Advantageously (figures 4 and 5), support plate 60 includes pins 80 to which the ends of conductive wire 50 are soldered. Preferably, the pins pass through the thickness of support plate 60 through a through opening made in support plate 60. Tests have shown that through-hole pins offer better strength than non-through pins and better resistance to wire pull-out and greater durability.

According to a variant embodiment ( ), amplifiers 90 are fixed to the support plate 60. As a result, the antenna (conductive wire 50) and the amplifier 90 are close (a few millimeters to a few centimeters) to each other, which allows save the installation of a connecting element between the antenna and the amplifier. Thus, the signal is not subject to any degradation linked to such a connecting element, and the resonance frequency of the antenna is then better controlled.

However, according to a variant, the amplifiers are deported outside the volume 20, for maintenance reasons or to save space around the antenna.

According to a variant embodiment, the support plate 60 comprises stiffening ribs, on which the conductive wire 50 is at least partially deposited.

Figures 4 and 5 illustrate an example in which the wall 40 comprises four different types of antenna: the wall comprises four wires 50 of different lengths, and the wires 50 form different patterns, specific to their function.

List of references

10: body part

12: first part of the body part forming a lining

14: second part of the bodywork part forming a skin

20: internal volume of the bodywork part

30: set of plastic walls delimiting the volume 20

40: wall on which at least one conductive wire 50 is deposited

50: conductive wire deposited on the wall 40 so as to form a means of receiving waves from an antenna

60: plastic support plate added in volume 20

70: ribs of the wall 40

80: support plate pins 60

90: amplifiers

Claims (7)

Bodywork part (10) comprising a volume (20) delimited by walls (30) made of plastic material, characterized in that the volume (20) comprises a wall (40) on which at least one conductive wire (50) is deposited so as to form a means of transmitting/receiving waves from an antenna. Bodywork part (10) according to claim 1, in which the wall (40) provided with the conducting wire (50) is one of the said walls (30) delimiting the volume (20). Bodywork part (10) according to Claim 1, comprising a plate (60) of plastic material added inside the volume (20), the said plate (60) comprising the wall (40) provided with the conductive wire (50). Bodywork part (10) according to one of the preceding claims, in which the wall (40) provided with the conductive wire (50) comprises ribs (70), the conductive wire (50) being at least partially deposited on the said ribs ( 70). Part according to Claim 1, in which the conductive wire (50) is deposited by ultrasound on the wall (40), or the conductive wire (50) is added by clipping onto the wall (40) in notches or flexible elements. Bodywork part (10) according to one of the preceding claims, comprising a first part (12) forming a lining and a second part (14) forming a skin, the two parts (12, 14) being fixed to one other so as to provide a space between the two parts (12, 14) forming the volume (20). Body part (10) according to one of the preceding claims, constituting a motor vehicle roof, or a motor vehicle tailgate, or a motor vehicle spoiler.