Body component element including a heating film

Abstract

The present invention relates to a method for manufacturing an element (1) for a vehicle body part, the method comprising the following successive steps: - Step A: implementing a support element (10, 20) having a first face (11, 21) on which a support sheet (3) including at least one connection member (4) is fixed, - Step B: placing at least one heating track (5) on the support element (10, 20), the heating track (5) being arranged on the first face (11, 21) of the support element (10, 20), - Step C: connecting the heating track (5) to the connection member (4), - Step D: placing the support element (10, 20) in a mold cavity that defines the shape of the element for the vehicle body part, the first face (11, 21) of the support element (10, 20) facing the interior of the mold cavity, and then injecting a plastic material into the mold cavity to cover the heating track (5).

Description

Field of the Invention

[0001] The present invention relates to the field of motor vehicles. More particularly, it relates to the field of manufacturing plastic elements intended to be mounted on body parts. Background Art

[0002] Many modern vehicles are equipped with plastic body parts, for example, which can be mounted on the rear tailgate, door panels, front and rear bumpers, or the roof, etc.

[0003] In particular, due to the introduction of driving assistance systems, it is necessary to arrange various types of sensors on certain plastic body parts in order to measure external physical parameters characterizing the external environment of the motor vehicle. All values of these parameters form information that is available in real time for the vehicle environment.

[0004] Then, we use a body element attached to the body part and having, for example, the function of a radome, that is to say, the element is transparent to electromagnetic waves and protects and hides the sensors. Generally, "transparent" should be understood as: the ability of a material to transmit more than 90% of the incident wave flux passing through it. Hereinafter, the term "transparent" will be used to refer to this definition.

[0005] For example, bumpers are now often equipped with proximity radars that assist the driver during the low-speed parking phase.

[0006] When the temperature is below 10 degrees Celsius, some sensors (such as those in the above example) are damaged in their normal operation due to the presence of ice, snow or frost. The frost layer disrupts the normal passage of electromagnetic waves, which is a source of error when evaluating external physical parameters.

[0007] To avoid frosting, which not only makes the assistance system unusable but also generates false alarms, it is necessary to provide a de-icing system on the elements of the body part, for example, the area of the body part that serves as a radome.

[0008] Such a de-icing (or defrosting) system is traditionally formed by heating tracks, which are composed of wires capable of converting electrical energy into heat energy and are connected to two connection plates arranged at each end of the heating track to supply current to it. The system is located on the body part element near the sensor. The heat energy thus released enables local defrosting in the case of the formation of a frost layer.

[0009] For example, a heated radome is known from patent document US2018 / 0269569, which includes a flexible printed circuit (or PCB: printed circuit board) forming a film, and the film is molded on the back with a thermoplastic material. The printed circuit includes a metal structure made of linear strips. The radome also includes a connector for connecting the printed circuit to a power source. The radome as described in this document requires a film large enough to cover the entire area to be heated, which is equivalent to the surface of the radome. Therefore, two layers of plastic are separated from each other by a film with a large coverage area, which makes the radome not very strong and not very waterproof. Additionally, since the heating element is supported by the thin film, the thin film exists over the entire area to be heated. Due to the presence of the thin film, the transparent area of the radome will be reduced. Therefore, the aesthetic quality of the radome decreases. Summary of the Invention

[0010] An object of the present invention is in particular to provide an element, such as a radome, intended to be mounted on a vehicle body part, which is more robust and aesthetically pleasing.

[0011] To this end, the subject of the present invention is a method for manufacturing an element for a vehicle body part, which method successively comprises the following steps:

[0012] - Step A: Implement a support element having a first face on which a support sheet including at least one connection member is fixed,

[0013] - Step B: Place at least one heating track on the support element, the heating track being arranged on the first face of the support element,

[0014] - Step C: Connect the heating track to the connection member,

[0015] - Step D: Place the support element in a cavity of a mold, the cavity defining the shape of the element for the vehicle body part, with the first face of the support element facing the inside of the cavity, and then inject a plastic material into the cavity to cover the heating track.

[0016] The method proposed by the present invention makes it possible to arrange one or more heating tracks where heat input is required, which increases the defrosting efficiency. Additionally, substantially all of the support element is separated from the molded layer only by the heating track, which makes it possible to reduce the space between the layers and increase the strength of the final part. Since there is almost no liner on all elements, the aesthetic quality of the vehicle body part element is also improved. In fact, the support sheet including the connection member can be easily moved to an area that is hardly visible from the outside of the vehicle.

[0017] According to the present invention, the support sheet is a flexible sheet, such as a flexible printed circuit, which can withstand mechanical torsion and save space compared to using a rigid circuit or manual wiring. The connecting member can be formed by a conductive plate or a metal pin, and the heating track can be formed by a conductive wire.

[0018] According to other optional features of the manufacturing process, the following can be used alone or in combination:

[0019] - The support element is a film made of plastic material, and step A includes the following steps:

[0020] - Implement a film made of plastic material,

[0021] - Fix a support sheet including at least one connecting member to the first face of the film.

[0022] Fixing the support sheet to the film ensures the firmness of the support sheet during the overmolding step of the film. This fixing can be done by gluing, welding or even using tape. The film is obtained by extrusion or lamination, but existing films on the market can also be used.

[0023] - The manufacturing method includes the following step: applying a coating to the second face of the support element opposite to the first face. This coating improves the resistance of the support element to ultraviolet rays or scratches. The coating can be a varnish or a coating obtained by a hard coating treatment.

[0024] - The support element is a molded part, and step A includes the following steps:

[0025] - Arrange the support sheet in the cavity of the mold, the support sheet includes at least one connecting member, the cavity defines the shape of the support element, the first face of the support sheet faces the inside of the cavity, and then inject plastic material into the cavity to obtain a molded part covering the first face of the support sheet,

[0026] - Arrange at least one connecting element on the second face of the support sheet opposite to the first face.

[0027] - Before step D, the following step is included: placing a protection device for the connecting member on the support sheet to protect at least a part of the connecting member from the plastic material injected in step D. The protection device has a space for accommodating at least part of the connecting member, so that the connecting member is isolated from the plastic material injected during molding, while maintaining its channel for connection to the power supply.

[0028] - The heating track is connected to the connecting device by welding. The type of the weld can have different properties, such as TC welding (or thermocompression welding in French) or electric welding.

[0029] - The support sheet includes a plurality of connecting elements electrically connected to each other by connecting means integrated in the support sheet. Steps B and C consist in arranging a corresponding number of heating tracks on the support element and connecting each heating track to one connecting element. The heating tracks can then be arranged independently, which is beneficial for distributing the heating zones as needed and improving the aesthetic appearance of the radome.

[0030] - The heating tracks are fixed to the support element by bonding or by locally melting the support element; - The heating tracks include a material selected from copper, tungsten, or an alloy of copper and tungsten.

[0031] - The support sheet is made of a sheet of silicone, polyolefin (polyethylene or polypropylene), thermoplastic elastomer (TPE), polyester, or polyamide. The support sheet can also be made of epoxy resin. The material overmolded on the support sheet is selected such that it can be chemically compatible with the film to ensure good bonding and ensure minimal interfacial defects.

[0032] The subject of the invention is also an element for a vehicle body part, which includes a first transparent plastic layer, a second transparent plastic layer, and heating tracks arranged between the transparent plastic layers and connected to a connecting member, the heating tracks being in direct contact with the first layer and the second layer. Description of the Drawings

[0033] The present invention will be better understood by reading the following description, which is given by way of example only and with reference to the accompanying drawings, in which:

[0034] - Figure 1 is a perspective view of an element for a vehicle body part according to the invention;

[0035] - Figure 2 is a perspective view of an element of a vehicle body part equipped with a protection device Figure 1 ;

[0036] - Figure 3 is a set of diagrams ( Figure 3 a - 3e) showing the different steps of the manufacturing process of an element of a vehicle body part according to a first embodiment;

[0037] - Figure 4 is a set of diagrams ( Figure 4 a - 4f) showing the different steps of the manufacturing process of an element of a vehicle body part according to a second embodiment;

[0038] - Figure 5 is a perspective view of a vehicle body element partially cut in a plane orthogonal to the support sheet obtained according to the second embodiment. Detailed Description

[0039] InFigure 1 and Figure 2 shows an element of a body part represented by the general reference numeral 1, which is manufactured according to the method proposed by the present invention. The manufacturing process includes a first step in which a support element 10 or 20 having first surfaces 11, 21 is manufactured, on which a support sheet 3 including at least one connecting member 4 is fixed. The connecting member 4 is formed of a conductive plate. The connecting member 4 connects at least one heating track 5 to an energy source. As described below, the support sheet 3 may include one or more connecting elements 4' connected to each other and to the connecting member 4, and each connecting element 4' may be connected to the heating track 5. Those skilled in the art understand that the various possibilities for manufacturing the circuits for connecting the various aforementioned elements will not be the subject of a detailed description in this application.

[0040] In Figure 3 and Figure 4 two embodiments are respectively shown and will be described in detail below. In both embodiments, the heating track 5 is arranged on the support elements 10, 20 and is located on the first face 11 or 21 of the support element 10 or 20. The heating track 5 may be formed of a wire conductor. Then, the heating track 5 is connected to the connecting member 4 (e.g., by soldering), and the support element 10 or 20 is arranged in a mold cavity defining a mold shape. For the body part, the first face 11 or 21 of the support members 10, 20 faces the inside of the mold cavity, and a plastic material is injected into the mold cavity to cover the heating track 5.

[0041] During the (plastic material) injection process, a protective device 7 for the connecting member 4 may be placed around the connecting member 4 to protect the connecting member 4 from the subsequently injected plastic material by isolating it therefrom, thus ensuring its connection to the power supply device.

[0042] Advantageously, the protective device 7 is a connector base that enables the connecting member 4 to be connected to the power supply device by accommodating a connector (not shown). Thus, the formed assembly already includes means for fixing the connector.

[0043] In the case where the protective device 7 includes an opening that enables the connecting member 4 to be connected to a connector (e.g., if the protective device 7 is a connector base including a wall (or column frame) 72 around the connecting member), the mold for injecting the plastic material includes a groove (or notch) 8 (see the numbering in Figure 4 a), and the wall 72 is then received in the groove to close the opening, thereby preventing the plastic material from entering the interior of the protective device 7 and then covering the connecting member 4 through the adjustment between the wall 72 and the groove 8.

[0044] As will be described later, the number of moldings can vary according to the embodiment. Thus, the design configuration of closing the opening in the groove 8 can be repeatedly implemented for the protection of the connecting member 4 in each molding.

[0045] Now, we will describe the first embodiment visible in Figure 3 a-3e. According to this embodiment, the support element 10 is a film made of plastic material as shown in Figure 3 a. Before fixing the support sheet 3 including at least one connecting member 4 on the first face 11 of the film (as shown in Figure 3 b), the film can be prepared by extrusion or lamination. Commercially available films can also be used. The film forms the first transparent layer.

[0046] As shown in Figure 3 c, a heating track 5 is arranged on the film, and the heating track 5 is provided on the first face 11 of the support element 10. Then, the heating track 5 is connected to the connecting member 4 of the support element 10, for example, by welding. The heating tracks 5 are uniformly distributed over the entire surface of the film and are attached thereto by adhesion or local melting of the film.

[0047] Then, a molding step is carried out, in which the support element 10 is placed in the mold cavity (forming cavity) of the mold, the mold cavity defining the shape of the element for the body part, the first face 11 of the support element 10 facing the inside of the mold cavity, and plastic material is injected into the mold cavity to cover the heating track 5. Thus, a second transparent layer 13 is obtained, as shown in Figure 3 d. The mold cavity of the element of the body part is arranged such that after molding, the connecting member 4 can be connected to a power source. Therefore, the thickness of the second transparent layer 13 is less than the thickness of the connecting member 4. Also during this step, the protection of the connecting member 4 can be achieved by placing the protection device 7 as described above before this step.

[0048] To increase the resistance of the element to ultraviolet rays and protect it from scratches, a coating 6 can be applied on the second face 12 of the film opposite to the first face 11, as shown in Figure 3 e. This step can also be provided in the second embodiment shown in Figure 4 and 5 .

[0049] According to the second embodiment of the present invention, the support element 20 is a molded part forming the first transparent layer, which is obtained by the following steps: placing a support sheet 3 including at least one connecting member 4 in the mold cavity of the mold, the mold cavity defining the shape of the part to be molded, as shown in Figure 4 a. The first face 31 of the support sheet 3 is placed facing the inside of the mold cavity. When the mold is closed, as shown in Figure 4As shown in Fig. b, a plastic material, such as a thermoplastic material, is injected into the mold cavity to obtain a molded part that covers the first surface 31 of the support sheet 3, as shown in Figure 4 Fig. c. The mold cavity of the molded part 20 is arranged such that the thickness of the molded part 20 is less than the thickness of the connecting member 4, so that the connecting member 4 can be connected to the power supply. As can be seen in Figure 4 Figs. 4a to 4c, the protection device 7 can be placed around the connecting member 4 during this first molding to isolate it from the injected plastic material as described above.

[0050] Subsequently, as Figure 4 shown in Fig. d, a plurality of connecting elements 4' are provided on the second surface 32 of the support sheet 3 opposite to the first surface 31, and these connecting elements 4' are electrically connected to each other through connecting means integrated into the support sheet 3. Moreover, all the connecting elements 4' are also connected to the connecting member 4 located on the first surface 31.

[0051] After the overmolding of the transparent first layer (or support element 20), and as Figure 4 shown in Fig. e, the heating tracks 5 are arranged on the first layer, and each heating track 5 is connected to the connecting element 4' on the second surface 32 of the support sheet 3 by welding. For example, it can be a plurality of wires as described above that form a heating area (for the first embodiment of the present invention, such a design structure with a plurality of connecting elements 4' and a plurality of heating tracks 5 is also feasible). The heating tracks 5 are evenly distributed on the entire surface of the transparent first layer and are fixed thereto by adhesion or local melting of the first layer.

[0052] Finally, the assembly including the first layer, the support sheet 3 and the heating tracks 5 is placed in the mold cavity of the mold, and the mold cavity defines the shape of the element for the vehicle body part, and the first surface 21 of the support element 20 faces the inside of the mold cavity. As Figure 4 shown in Fig. f, another plastic material, such as thermoplastic polyurethane (TPU), is injected into the mold cavity to cover the heating tracks 5. Similarly, the protection device 7 can protect the connecting member 4 (for example, the opening of the protection device 7 can be placed in the notch 8 again).

[0053] According to the first or second embodiment, an element 1 for a vehicle body part is obtained, which simultaneously includes a first transparent plastic layer (corresponding to the support element 10 or 20), a second transparent plastic layer 13, 23, and at least one heating track 5. The heating track 5 is arranged between the transparent plastic layers and is connected to the connecting member 4, and the heating track 5 is in direct contact with the first and second layers.

[0054] Such an element 1 obtained by the manufacturing method according to the second embodiment is visible in Figure 5 which shows another aspect of the present invention, which relates to the protection device 7 of the connecting member. AsFigure 1 and Figure 2 As shown in Figure 2 , the protection device 7 includes a base 71 designed to abut against the support sheet 3 and a wall 72 extending from the base 71 and defining a space for accommodating at least a part of the connection member 4, so that the latter is isolated from the plastic injected during the molding process while maintaining its connection path to the power supply.

[0055] The present invention is not limited to the presented embodiments, and other embodiments will be obvious to those skilled in the art. In particular, a plurality of connection members can be arranged and electrically connected together in the first embodiment. When the elements are assembled on a vehicle, a ring or an opaque technical area can also be provided to hide the support sheet.

[0056] List of reference numerals:

[0057] 1: Element

[0058] 10, 20: Support elements (first layer)

[0059] 13, 23: Second layer

[0060] 11, 21: First face of the support element

[0061] 12: Second face of the support element

[0062] 3: Support sheet

[0063] 31: First face of the support sheet

[0064] 32: Second face of the support sheet

[0065] 4,: Connection member

[0066] 4’: Connection element

[0067] 5: Heating track

[0068] 7: Protection device

[0069] 71: Base of the protection device

[0070] 72: Wall of the protection device

[0071] 8: Groove or notch

Claims

1. A manufacturing method for manufacturing an element (1) for a vehicle body part, the method comprising the following sequential steps: - Step A: Implement a support element having a first face, on which a support sheet (3) including at least one connection member (4) is fixed. - Step B: Place at least one heating track (5) on the support element, the heating track (5) being arranged on the first face of the support element. - Step C: Connect the heating track (5) to the connection member (4). - Step D: Place the support element in a cavity of a mold, the cavity defining the shape of the element for the vehicle body part, the first face of the support element facing the interior of the cavity, and then inject a plastic material into the cavity to cover the heating track (5). Among them, Before step D, the following steps are further included: - Place a protection device (7) of the connection member (4) on the support sheet to protect at least a part of the connection member (4) from the plastic material injected in step D.

2. The manufacturing method according to claim 1, wherein The support element is a film made of plastic material, and step A includes the following steps: - Implement a film made of plastic material. - Fix a support sheet (3) including at least one connection member (4) to the first face of the film.

3. The manufacturing method according to any one of the preceding claims, including the following step: - Apply a coating (6) to the second face (12) of the support element opposite to the first face.

4. The manufacturing method according to claim 1, wherein The support element is a molded part, and step A includes the following steps: - Arrange a support sheet (3) including at least one connection member (4) in a cavity of a mold, the cavity defining the shape of the support element, the first face (31) of the support sheet (3) facing the interior of the cavity, and then inject a plastic material into the cavity to obtain a molded part covering the first face (31) of the support sheet (3). - Arrange at least one connection element (4') on the second face (32) of the support sheet (3) opposite to the first face (31).

5. The manufacturing method according to claim 1 or 2, wherein The heating track (5) is connected to the connection member (4) by welding.

6. The manufacturing method according to claim 1 or 2, wherein The support sheet (3) includes a plurality of connection elements (4') electrically connected to each other through connection means integrated in the support sheet (3). Steps B and C consist in arranging a corresponding number of heating tracks (5) on the support element and connecting each heating track (5) to one connection element (4').

7. The manufacturing method according to claim 1 or 2, wherein, The heating track (5) is fixed to the support element by adhesion or by local melting of the support element.

8. The manufacturing method according to claim 1 or 2, wherein The heating track (5) includes a material selected from copper, tungsten, or an alloy of copper and tungsten.

9. The manufacturing method according to claim 1 or 2, wherein The support sheet (3) is made of a sheet of silicone resin, polyolefin, thermoplastic elastomer (TPE), polyester, or polyamide.

10. The manufacturing method according to claim 9, wherein, The support sheet (3) is made of a sheet of polyethylene or polypropylene.

11. An element for a vehicle body part, including a first transparent plastic layer, a second transparent plastic layer (13, 23), and a heating track (5) arranged between the transparent plastic layers and connected to a connection member, the heating track (5) being in direct contact with the first and second layers. Characterized in that, The element further comprises a protection device (7) for the connecting member (4), the protection device (7) being arranged on a support tab (3) comprising the connecting member (4) so as to protect at least a portion of the connecting member (4) from the plastic material injected during the step of moulding the element for a bodywork part.

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