FR3105376A1 - Manufacturing process of a heating structure - Google Patents

Abstract

The invention relates to a method of manufacturing a heating structure (3) intended to be installed inside a passenger compartment (1) of a vehicle (2), the manufacturing method comprising in particular the steps of: create a substantially planar heating structure comprising a support (21) capable of assuming a shape determined by deformation, a dissipative layer (20) arranged to generate heat when it is traversed by an electric current, and electrodes (10) arranged to generate said electric current, overmold the heating structure (3) so as to integrate at least one additional component and / or at least one additional layer. Figure for the abstract: Fig. 3

Description

Process for manufacturing a heating structure

The field of the present invention relates to radiant panels arranged inside a vehicle cabin, for example an automobile. The invention relates more particularly to a method of manufacturing a heating structure intended to heat the passenger compartment.

Today, the management of the comfort and well-being of passengers in a vehicle follows developments in mobility (eco-sharing, carpooling, electrification, connectivity, etc.). In the age of autonomous driving and new sharing practices, user expectations have changed. The passenger compartment is no longer perceived as a waiting area but also as a space for relaxation and conviviality.

These heating structures actively contribute to the comfort of the users of the vehicle in the passenger compartment of which they are integrated. The surface of the structure heats the passengers by infrared radiation while heating the air located inside the passenger compartment by convection or by contact (for example in the case of an armrest). They have shapes and dimensions adapted to their location within the vehicle. They can for example be integrated into a seat, a dashboard, a roof, a pillar, an armrest, etc. A heating structure can therefore be perceived as an interface whose main function is to ensure thermal comfort within the passenger compartment of the vehicle.

A heating structure, in particular a radiant panel, is a device generally comprising an electric circuit configured to deliver heat by the Joule effect by supplying resistive conductive elements with electric current. These can be wireframe elements or surface coverings. According to the existing literature, the conductive coating can be, for example, a layer of paint comprising carbon particles and/or metallic particles. A problem raised today is the difficulty of obtaining homogeneous heating over the entire surface of the radiant panel, that is to say a heating temperature which does not vary from one point to another on the surface of the radiant panel. radiant panel. Added to this drawback are geometric constraints, including three-dimensional shaping, since the radiant panel is intended to be placed in different parts of the passenger compartment (roof, door, pillar, glove box, etc.).

The manufacture of such a structure is all the more complex as it is necessary to have limited thicknesses whether at the level of the heating structure and/or at the level of the decorative layer so as to be able to install it on any three-dimensional structure of the vehicle.

The object of the present invention is to remedy at least some of the aforementioned drawbacks by simplifying the manufacturing process.

The subject of the invention is a process for manufacturing a heating structure intended to be installed inside the passenger compartment of a vehicle, the manufacturing process comprising in particular the steps consisting in:

1. creating a substantially planar heating structure comprising a support capable of taking a determined shape by deformation, a dissipative layer arranged to generate heat when an electric current passes through it, and electrodes arranged to generate said electric current,
2. overmolding the heating structure so as to integrate at least one additional component and/or at least one additional layer.

Such a method thus makes it possible to manufacture the necessary heating structure before any deformation, using known standard methods. It is thus possible to imagine a simplified manufacture of the heating structures with shaping carried out in the last step of the process.

According to one or more characteristic(s) which can be taken alone or in combination, it can be provided that:

• the support can be a flexible material. It may, for example, be a non-woven fabric or even a stretch fabric or stretch knit;
• the substrate can be made of thermoplastic material;
• the method may include at least one step in which a deformation on at least part of the heating structure is carried out;
• the heating structure may include a thermal insulation layer;
• the thermal insulation layer may be placed at the rear of the heating structure, in particular against a wall of the passenger compartment;
• the heating structure may include a decorative layer, said decorative layer being preferably added on the dissipative layer side;
• the deformation can be achieved through a thermoforming process;
• the electrodes and/or the dissipative layer and/or the thermal insulation layer and/or the decorative layer can be produced by co-rolling;
• the electrodes and/or the dissipative layer and/or the thermal insulation layer and/or the decorative layer can be made by gluing;
• the electrodes and/or of the dissipative layer can be produced by screen printing, offset, ink jet printing, by additive manufacturing, by hot stamping and transfer or by electrodeposition;
• the thermal insulation layer and/or the decorative layer can be made of a thermoplastic material;
• the thermoplastic material is preferably chosen from the following list: a polycarbonate and/or a polyethylene terephthalate and/or a polymethyl methacrylate and/or a polybutylene terephthalate and/or a polyamide material and/or a polyolefin and/or a copolymer material and /or an elastomeric material;
• the support preferably has a thickness comprised between 5 μm and 2 mm, preferably greater than 50 μm;
• the thermal insulation layer may have a thickness of between 5µm and 20mm, preferably between 1mm and 5mm;
• the electrodes and/or the dissipative layer may have a thickness of less than 100 microns;
• the dissipative layer may comprise an extensible resistive sheet and/or a resistive paint layer and/or a resistive ink;
• the support may be electrically insulating;
• the electrical power supplied to the heating structure can be generated from a DC signal or from a pulse-width modulated (PWM) signal so as to supply an average power to the dissipative region;
• electrical connection elements can be added during the overmolding step;
• plastic connectors on the electrical connections can be added during the overmolding step;
• clips or any other means enabling the part to be assembled directly during the heating structure assembly step, arranged to install the heating structure in the passenger compartment, can be added during the overmolding step.

Other characteristics, details and advantages of the invention will become apparent on reading the description given below for information purposes in relation to drawings in which:

• Fig. 1 is a schematic view of a vehicle interior in which one or more heating structures according to the invention are positioned,
• Fig. 2 is a schematic representation of an embodiment of the heating structure of FIG. 1,
• Fig. 3 is a sectional view of the heating structure of Figure 2.

The features, variants and different embodiments of the invention may be associated with each other, in various combinations, insofar as they are not incompatible or exclusive of each other. One can in particular imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from to the state of the prior art.

In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

It should be noted that the figures expose the invention in detail to implement the invention. Said figures can of course be used to better define the invention, if necessary.

In the figures, the elements common to several figures retain the same reference.

Figure 1 illustrates a passenger compartment 1 of a motor vehicle 2 equipped with at least one heating structure 3 according to the invention. Heating structures 3 according to the invention are distributed within the passenger compartment 1 to locally generate heat in the direction of the areas intended to be occupied by one or more users of the motor vehicle 2. According to the example illustrated in FIG. 1, the structures heaters 3 according to the invention are arranged on different interior surfaces of the passenger compartment 1, such as for example a door 4, a roof 5, a seat 6, an element of a seat 6 (headrest, a backrest, a foot seat, etc.), a dashboard 7, a lower part of the dashboard such as a foot cellar 8 and/or an armrest 9. Of course, other interior surfaces could be equipped with heating structures 3 according to the invention according to the needs of each user and/or according to the configuration of the passenger compartment 1. By interior surface is meant any surface facing the areas of the passenger compartment 1 occupied by the passengers of the vehicle car 2.

FIG. 2 represents a radiant panel 3, forming a heating structure within the meaning of the invention, arranged to be installed inside the passenger compartment 1 of a vehicle.

Initially, the radiant panel 3 is produced in a known manner thanks to a multilayer process making it possible to integrate the various functionalities and create the two-dimensional heating structure.

Figure 2 shows a radiant panel 3 according to the invention comprising a dissipative layer 20 arranged to produce heat release when this layer 20 is traversed by an electric current. The dissipative layer 20 is shown in a rectangular shape but can, of course, take any other shape. It may, for example, be in an oval, square, circular or even trapezoidal shape depending on the layout within the passenger compartment 1. These shapes are given by way of illustrative and non-limiting examples of the present invention.

The dissipative layer 20 is for example an acrylic paint filled with conductive or semi-conductive particles. The conductive filler is for example in the form of flakes of carbon and graphite.

The radiant panel 3 further comprises a network of electrodes 10 comprising a plurality of contact electrodes 11 arranged to be in electrical contact with the dissipative layer 20 to cause electrical current to flow through this dissipative layer 20.

These contact electrodes 11 are rectilinear and parallel to each other in the example described. They may optionally have any shape desired by the user.

The network of electrodes 10 comprises distribution electrodes 12 arranged to conduct electric current, one of these electrodes 12 being connected from an electric source 13, for example of positive electric polarity, to the contact electrodes 11. another distribution electrode 12 is connected to the other polarity, being for example connected to ground.

The electric current thus passes through a distribution electrode 12, which distributes it to the contact electrodes 11. The current then flows through the dissipative layer 20 before being collected by the contact electrodes 11 connected to the other distribution electrode 12.

Several contact electrodes 11 are connected to the same distribution electrode 12.

In FIGS. 2 and 3, the dissipative layer 20 is deposited, for example, on a support 21, in particular by screen printing, this dissipative layer 20 extending in particular between the two distribution electrodes 12 associated with the group of contact electrodes 11 .

In an embodiment not shown, the dissipative layer 20 can also be deposited directly on a decorative layer, for example by screen printing. The technique of deposition by screen printing is, of course, given by way of example. A person skilled in the art can also use any other known deposition technique, such as, for example, by offset, by inkjet printing, by electrodeposition or even by stamping.

The electrodes 11 and 12 are made of conductive material, in particular metal such as ink loaded with conductive particles, in particular particles of silver or copper.

The support 21 is made of a deformable material which can for example be in the form of a thermoplastic material. This support 21 can for example be chosen from the following list:

• a polycarbonate,
• a polyethylene terephthalate,
• a polymethyl methacrylate,
• a polybutylene terephthalate,
• a polyamide material,
• a polyolefin,
• a copolymer material,
• an elastomeric material (for example a TPE (thermoplastic elastomer)).

The support 21 has, for example, a thickness of between 5 μm and 2 mm, preferably greater than 50 μm.

In a preferred embodiment, the radiant panel 3 according to the invention, manufactured as described in the preceding paragraphs, is deformed to create the desired shape for integration into the passenger compartment 1. This deformation is preferably carried out using processes known such as thermoforming or hot stamping. It can also be carried out by simple heating of the heating structure.

The maintenance of the radiant panel 3 is for example carried out by moving elements in a mould. These are preferentially retractable at the time of the injection carried out during the overmolding step.

Thus, complex surfaces having curvatures along the axes in three dimensions are created. The finished product is therefore ready to be directly installed in the passenger compartment 1 without requiring long and/or expensive processing. The installation can, for example, be carried out very easily thanks to clips previously installed on the radiant panel 3.

Substrate 21 can also be formed from a flexible material. In this embodiment, said substrate 21 automatically takes the shape of the mold before the overmolding step. This embodiment has the advantage of simplifying the method by excluding any additional heating step.

In a preferred embodiment of the invention, the method also comprises an overmolding step making it possible to add functional components and/or additional layers to the radiant panel 3 manufactured previously.

Figure 3 shows a section of a radiant panel 3 according to the invention. Thus, during the overmolding step, a thermal insulation layer 22 can be added to the panel 3. The thermal insulation layer 22 can, for example, be a layer of material having thermal insulation properties (sheet of felt or felt, polyurethane foam, polyethylene foam for example) and make it possible to avoid the dissipation of heat towards zones which do not allow the passenger compartment 1 to be heated.

The support 21 described above is arranged between the thermal insulation layer 22 and the dissipative layer 20. As shown in Figure 3, the dissipative layer 20 can also be integral with a decorative layer 23 serving as a covering conferring an aesthetic appearance. to the radiant panel 3.

The decorative 23 and thermal insulation 22 layers can be made of a thermoplastic material similar to or different from that used for the substrate 21. The thermoplastic materials can for example be:

• a polycarbonate,
• a polyethylene terephthalate,
• a polymethyl methacrylate,
• a polybutylene terephthalate,
• a polyamide material,
• a polyolefin,
• a copolymer material,
• an elastomeric material (for example a TPE (thermoplastic elastomer)).

In a preferred embodiment of the invention, the thermal insulation layer 22 and the decorative layer 23 are produced in a single overmolding step.

The material used for the overmolding step can be in the form of any plastic, preferably polypropylene.

During this same overmolding step, other components can also be added to the radiant panel 3. Thus, components such as:

• clips allowing the integration of the radiant panel 3 in the passenger compartment 1,
• electrical connections allowing the connection of the radiant panel 3 to the vehicle 2.

Thus, in a single overmolding step, the multilayer heating structure integrates the decorative and thermal insulation layers as well as the components allowing its integration into the passenger compartment 1. A finished product that is easy to install can therefore be supplied.

The functions that can be added are obviously not limited to those mentioned above. These examples are given for illustrative purposes. One could also add any component playing a role in the electrical and/or mechanical integration of the radiant panel 3. It is of course also possible to add decorative components to the radiant panel 3 during this same overmolding step.

Claims (10)

Process for manufacturing a heating structure (3) intended to be installed inside a passenger compartment (1) of a vehicle (2), the manufacturing process comprising in particular the steps consisting in:

1. create a substantially planar heating structure comprising a support (21) capable of taking a determined shape, a dissipative layer (20) arranged to generate heat when an electric current passes through it, and electrodes (10) arranged to generate said electric current,
2. overmoulding the heating structure (3) so as to integrate at least one additional component and/or at least one additional layer.

Method according to claim 1, in which the support (21) is a flexible material. Method according to Claim 1, in which the substrate (21) is made of thermoplastic material. Method according to Claim 3, in which at least one deformation on at least part of the heating structure (3) is carried out. Method according to one of Claims 1 to 4, in which the heating structure (3) comprises a thermal insulation layer (22). Method according to one of the preceding claims, in which the heating structure (3) comprises a decorative layer (23), said decorative layer (23) being preferably added on the side of the dissipative layer (20). Method according to one of the preceding claims, in which the thermal insulation layer (22) and/or the decorative layer (23) are made of a thermoplastic material. Process according to one of Claims 3 to 7, in which the thermoplastic material is chosen from the following list: a polycarbonate and/or a polyethylene terephthalate and/or a polymethyl methacrylate and/or a polybutylene terephthalate and/or a polyamide material and /or a polyolefin and/or a copolymer material and/or an elastomeric material. Method according to one of the preceding claims, in which the support (21) is electrically insulating. Method according to one of the preceding claims, in which electrical connection elements and/or clips arranged to install the heating structure (3) in the passenger compartment (1) are added during the overmolding step.