HEATING STRUCTURE FOR A MOTOR VEHICLE

Description

[0001] The present invention relates to a heating structure intended in particular to be installed inside a vehicle passenger compartment, this structure being in particular a radiant panel.

[0002] Generally, a radiant panel comprises a plurality of electrodes configured to deliver heat by Joule effect by supplying electric current to a conductive coating. For example, reference may be made to document US 2016 / 0059669 which describes such a radiant panel.

[0003] EP 2 123 120 B1 (PANASONIC CORP [JP]) September 30, 2015 (2015-09-30) discloses a heating structure intended in particular to be installed inside a vehicle passenger compartment, this structure being in particular a radiant panel, the heating structure comprising at least one resistive layer arranged to produce a thermal release when this layer is crossed by an electric current.

[0004] WO 00 / 43225 A2 (CHIOVATERO ANTOINETTE EF [US]; ILLINOIS TOOL WORKS [US] ET AL.) July 27, 2000 (2000-07-27) relates to a self-regulating flexible heating structure suitable for use in automotive components, but which may be used in other applications, including, but not limited to, furniture, consumer articles, building materials, and other articles.

[0005] A radiant panel is a device generally comprising an electrical circuit configured to deliver heat by Joule effect by supplying resistive conductive elements with electric current. These may be wire elements or surface coatings. According to existing literature, the conductive coating may be, for example, a layer of paint comprising carbon particles and / or metal particles. A problem raised today is the difficulty of obtaining homogeneous heating over the entire surface of the radiant panel, i.e. a heating temperature that does not vary from one point to another on the surface of the radiant panel. Added to this disadvantage are geometric constraints since the radiant panel is intended to be placed in different parts of the passenger compartment (roof, door, pillar, glove box, etc.).

[0006] The object of the present invention is to provide improved radiant panels.

[0007] The present invention thus provides a heating structure intended in particular to be installed inside a vehicle passenger compartment, this heating structure being in particular a radiant panel, the heating structure comprising at least one resistive layer arranged to produce a thermal release when this layer is crossed by an electric current, this structure further comprising an electrode network comprising a plurality of contact electrodes arranged to be in electrical contact with the resistive layer to cause electric current to flow through this resistive layer, at least some of these contact electrodes being arranged with an inter-distance between successive electrodes which is variable.

[0008] It is known that the thermal power created by the Joule effect depends on the supply voltage U as well as the electrical resistance R between the two electrodes, here two contact electrodes, and verifies the law: P = U 2 < / R. The resistance R is proportional to the distance d between the two contact electrodes.

[0009] The applicant has found that the electrical consumption of each area of ​​the resistive layer, between two consecutive contact electrodes, results in a voltage drop along the distribution electrode, and therefore along the pairs of contact electrodes. As the potential difference for these areas is related to the power supplied by the area with the power formula P = U 2 < / R, the heating structure provides less and less heating capacity along the pairs of contact electrodes. The invention makes it possible to counteract this phenomenon of heating heterogeneity and to provide homogeneous heating, thanks to these inter-distances between contact electrodes which are adapted to reduce the electrical resistance between two contact electrodes and thus have a dissipated power as homogeneous as desired.

[0010] The invention allows, to obtain this homogeneity, to use the same resistive coating or resistive layer, in particular of the same conductivity, with the same thickness. This allows the manufacturing process of the heating structure to be kept simple.

[0011] According to one aspect of the invention, the contact electrodes are, at least for some of them, in particular for all the contact electrodes of the electrode network, parallel to each other.

[0012] According to one aspect of the invention, the electrode network comprises distribution electrodes arranged to conduct electric current from an electrical source to the contact electrodes, several contact electrodes being connected to a single distribution electrode.

[0013] According to one aspect of the invention, at least one of the distribution electrodes is rectilinear over at least part of its length, and the contact electrodes which are associated with this distribution electrode are connected, for example perpendicularly, to this distribution electrode.

[0014] Of course, the distribution electrodes can have different shapes, including curved ones with rounded edges. The distribution electrodes can be parallel to each other or not.

[0015] According to one aspect of the invention, the electrode array comprises at least two distribution electrodes which are parallel to each other over at least part of their length, and their associated contact electrodes are arranged between these two distribution electrodes and are alternated with an inter-distance which decreases in relation to the decrease in the voltage present between the pairs of electrodes so as to maintain the electrical power between the pairs of contact electrodes substantially uniform.

[0016] According to one aspect of the invention, the contact electrodes arranged between two distribution electrodes, these contact electrodes being part of the same group of contact electrodes, have only two inter-distance values, or at least three or more inter-distance values.

[0017] According to one aspect of the invention, the resistive layer is a layer deposited on a substrate, in particular by screen printing, this resistive layer extending in particular between the two distribution electrodes associated with the group of contact electrodes.

[0018] According to one aspect of the invention, the resistive layer notably comprises carbon.

[0019] According to one aspect of the invention, the electrodes are made of conductive material, in particular metallic material such as ink loaded with conductive particles, in particular silver or copper particles. If desired, the electrodes are metallic adhesive tapes, for example copper. If necessary, these electrodes may possibly be made by depositing a material on the substrate

[0020] According to one aspect of the invention, the resistive layer associated with the group of contact electrodes is a continuous layer, or alternatively comprises a plurality of discrete resistive elements forming this layer.

[0021] According to one aspect of the invention, the contact electrodes of the same group have the same length.

[0022] According to one aspect of the invention, the heating structure comprises a substrate which carries the resistive layer and the electrodes. The substrate is preferably less than 1 cm thick, for an area of ​​at least several cm2.

[0023] The invention also relates to a component of a motor vehicle interior, in particular a component to be integrated into a door of the vehicle, or in particular parts of the dashboard, footwell trim, roof, armrest, comprising a heating structure, in particular a radiant panel, as mentioned above.

[0024] According to one aspect of the invention, the passenger compartment component which comprises the heating structure, for example the radiant panel, is arranged to heat by thermal radiation (radiant panel) or by thermal conduction or thermal contact (contact heating structure), and not by convection heating, for example by heat transported by moving air. In particular, the heating structure is not crossed by any air flow intended to cool or heat the passenger compartment. Preferably, the panel is disconnected from the air movement system.

[0025] The vehicle's heating structure and HAVC can, if desired, be controlled in a coordinated manner.

[0026] The component forms, for example, an element of a glove box or a vehicle door panel, or a passenger compartment roof.

[0027] The invention also relates to a heating structure having a resistive layer and electrodes for heating this layer, this structure being configured to be integrated into a passenger compartment component which comprises a decoration visible from the interior of the passenger compartment, this decoration being for example a covering of the passenger compartment, such as for example a fabric, a leather or an aesthetic coating.

[0028] The invention also relates, independently or in combination with the above, to a heating structure intended in particular to be installed inside a vehicle passenger compartment, this structure being in particular a radiant panel, the heating structure comprising at least one resistive layer arranged to produce a thermal release when this layer is crossed by an electric current, this structure further comprising an electrode network comprising a plurality of contact electrodes arranged to be in electrical contact with the resistive layer to cause electric current to flow through this resistive layer, the contact electrodes and the resistive layer are carried on a substrate made of a flexible material capable of taking a predetermined shape by deformation, this substrate being in particular also extensible.In particular, the elements of the heating structure form an extensible assembly, namely the substrate, the resistive layer and the contact electrodes are extensible and flexible.

[0029] According to one aspect of the invention, the contact electrodes are formed by entangled wires, in particular woven or knitted, on or in a respectively woven or knitted substrate. The conductive wires forming the contact electrodes are in contact with the resistive layer.

[0030] According to one aspect of the invention, the substrate is a nonwoven. This nonwoven may comprise a mixture of polypropylene fibers and / or polyester fibers. Other fibers may be used, for example natural fibers.

[0031] Alternatively, the substrate is a fabric, especially with stretch yarns, or a knitted structure.

[0032] According to one aspect of the invention, the substrate may be a flexible plastic sheet or a foam such as TPU (thermoplastic polyurethane).

[0033] Advantageously, to remain substantially invisible and / or imperceptible, the contact electrodes and / or the resistive layer must be sufficiently thin, in particular with a thickness of less than 100 microns, and be flexible. These electrodes and the resistive layer may comprise an extensible conductive ink and / or be inside the substrate.

[0034] According to one aspect of the invention, the resistive layer may comprise a stretchable resistive sheet, a resistive paint layer or a resistive ink. The resistive sheet is a sheet capable of releasing heat when an electric current passes through it.

[0035] According to one aspect of the invention, the conductive ink can be added to the substrate by screen printing, offset printing, inkjet printing, hot stamping and transfer, electroplating.

[0036] According to one aspect of the invention, the substrate may be a decorative element of the passenger compartment, in particular an element visible to passengers in the passenger compartment. This type of decorative substrate may be chosen from: a leather or imitation leather substrate, containing in particular PVC, a textile which may or may not be of the 3D type, a decorative plastic film.

[0037] The invention also relates to a heating structure intended in particular to be installed inside a vehicle passenger compartment, this structure being in particular a radiant panel, the heating structure comprising a set of tangled wires, certain wires of which form heating conductive wires arranged to produce heat when these heating wires carry an electric current.

[0038] In an exemplary embodiment of the invention, the substrate may be a stretchable textile that incorporates yarns as a heating material. Alternatively, the substrate may be a stretchable textile or a stretchable knit that incorporates yarns used as contact electrodes and the resistive layer is placed on the surface. The resistive ink is assembled, for example, onto the textile by lamination, screen printing, or hot stamping and transfer.

[0039] The substrate may be a knitted structure with at least one of the following yarns: non-stretchable yarns for the substrate, non-stretchable conductive yarns for electrodes, single-strand or multi-strand copper yarns, a conductive copper yarn, and non-conductive yarns for reasons of mechanical strength or ease of manufacture.

[0040] The knitted structure has the advantage that, even if the support wire and the conductive wire that forms, for example, an electrode are not stretchable, the structure of the knitting stitch makes the knitted structure stretchable. With a non-stretchable copper wire, the elongation potential of the knitted fabric is approximately 14%, for example.

[0041] According to one aspect of the invention, the heating structure comprises an electrical distribution circuit comprising distribution electrodes which transport the current from the connectors to the contact electrodes which are in contact, for example, with a resistive layer.

[0042] The contact and distribution electrodes are made of copper wire, for example.

[0043] When the substrate is woven, the stretchable characteristic can be achieved either by the arrangement of the woven structure, namely by the weaving technique, or by the intrinsic stretchability of the yarns used for weaving.

[0044] In particular, if the potential elongation of the conductive yarn is different from that of the main fibers of the fabric, the end of each conductor must remain free to move inside or outside the fabric.

[0045] If several contact electrodes are connected together to one of the distribution electrodes, the connection between the distribution electrode and the contact electrodes can be achieved by integrating the distribution electrode into the weaving weft and the contact electrodes into the weaving warp or vice versa. By means of an alternating passage on both sides of the woven structure, the connection between the electrodes is secured.

[0046] In order to have a continuous manufacturing process of the knitted or woven structure, it is possible to connect both sides of the contact electrodes to the distribution electrodes and then electrically neutralize a portion of these contact electrodes from the distribution electrode by cutting the wires of the contact electrodes by stamping them in a stamped area, or by integrating an electrical insulator at the location where the electrical connection is to be interrupted in an interrupted area.

[0047] Alternatively, it is possible to have a connector at the end of each contact electrode, or an external distribution electrode connecting all the contact electrodes together.

[0048] The invention also relates to a method of manufacturing a heating structure, comprising the steps of weaving or knitting a substrate and providing on the substrate heating or radiant zones formed by threads woven or knitted with the substrate, or by depositing a resistive layer on the substrate.

[0049] The invention makes it possible, for example, to provide a heating structure forming a decorated part of an interior of a motor vehicle, a part of complex shape. These complex surfaces can have curvatures along the axes in three dimensions.

[0050] In a disadvantageous way, not using the invention, the surface can be decorated with a layer of plastic film, leather or textile that makes any roughness or weakness in the thickness of the surface visible. This leads to a feeling of damage in the design of the part.

[0051] A problem with this approach is that interposing a smoothing material between the heating structure and the decoration surface results in thermal insulation which reduces the temperature of the decoration surface and thus reduces the heating power supplied to the cabin environment.

[0052] The electrical power required to have sufficient heating power (e.g. greater than 500 W / m2) giving a positive feeling of comfort under low voltage (e.g. less than 50 Volts) requires a sufficient section of conductive lines which are difficult to hide behind a decorative layer.

[0053] The invention makes it possible to have a heating structure with very low thickness defects, and extensible to adapt to the complex shape while remaining substantially imperceptible.

[0054] It is understood that all of the above characteristics and configurations are in no way limiting. Other characteristics, details and advantages of the invention will emerge more clearly on reading the detailed description given below, and several exemplary embodiments given for informational and non-limiting purposes with reference to the appended schematic drawings, in which: There figure 1 [Fig. 1 ] is a schematic representation of an exemplary embodiment of a radiant panel according to an exemplary embodiment of the invention; The figure 2 [Fig. 2 ] is a schematic representation of components including the radiant panel of the invention, The figure 3 [Fig. 3 ] is a schematic representation of another heating structure of the invention, The figure 4 [Fig. 4 ] is a schematic representation of another heating structure of the invention, The figure 5 [Fig. 5 ] is a schematic representation of another heating structure of the invention.

[0055] There figure 1 represents radiant panel 1, forming a heating structure within the meaning of the invention, arranged to be installed inside a passenger compartment 3 of a vehicle.

[0056] The radiant panel 1 comprises a resistive layer 4 arranged to produce a thermal release when this layer 4 is crossed by an electric current.

[0057] The resistive layer 4 is, for example, an acrylic paint loaded with conductive or semi-conductive particles. The conductive filler is, for example, in the form of carbon and graphite flakes.

[0058] This panel 1 further comprises an electrode network 5 comprising a plurality of contact electrodes 6 arranged to be in electrical contact with the resistive layer 4 to cause electric current to flow through this resistive layer 4.

[0059] These contact electrodes 6 are arranged with an inter-distance D1, D2 ... Di between successive electrodes, inter-distance which is variable.

[0060] These contact electrodes 6 are rectilinear and parallel to each other in the example described.

[0061] The electrode network 5 comprises distribution electrodes 8 arranged to conduct electric current, one of these electrodes 8 being connected from an electrical source 9, for example of positive electrical polarity, to the contact electrodes 6. The other distribution electrode 8 is connected to the other polarity, being for example connected to a ground.

[0062] The electric current thus passes through a distribution electrode 8, which distributes it to the contact electrodes 6. The current then flows through the resistive layer 4 before being collected by the contact electrodes 6 connected to the other distribution electrode 8.

[0063] Several contact electrodes 6 are connected to the same distribution electrode 8.

[0064] The distribution electrodes 8 are rectilinear over part of their length, or even their entire length, and the contact electrodes 6 which are associated with these distribution electrodes 8 are connected perpendicularly to this associated distribution electrode 8.

[0065] Here the electrode network 5 comprises two distribution electrodes 8 which are parallel to each other, and their associated contact electrodes 6 are arranged between these two distribution electrodes 8 and are alternated with an inter-distance D1, D2.. Di which decreases in relation to the decrease in the voltage U1, U2... Ui present between the pairs of electrodes 6 so as to maintain the electrical power substantially uniform between the pairs of contact electrodes.

[0066] The contact electrodes 6 arranged between the two distribution electrodes 8, these contact electrodes being part of the same group 14 of contact electrodes, have a plurality of inter-distance values ​​D1, D2 ... Di. In the example described, we have D1>D2>D3> D4, and U1>U2>U3> U4 for the voltages between the electrodes 6.

[0067] The resistive layer 4 is a layer deposited on a substrate 16, in particular by screen printing, this resistive layer 4 extending in particular between the two distribution electrodes 8 associated with the group of contact electrodes.

[0068] Electrodes 6 and 8 are made of conductive material, in particular metallic material such as ink charged with conductive particles, in particular silver or copper particles.

[0069] In the example described, the resistive layer 4 associated with the group of contact electrodes is a substantially rectangular continuous layer. Other shapes are of course possible.

[0070] The contact electrodes 6 of the same group 14 have the same length. Alternatively, the electrodes 6 may be of different lengths.

[0071] In an example not shown, several pairs of distribution electrodes 8 can be provided, and there are then several groups 14 of contact electrodes 6.

[0072] A motor vehicle passenger compartment component 19, in particular a component to be integrated into a vehicle door, is provided with a radiant panel 1. Several components can be reviewed in the passenger compartment.

[0073] The component 19 may comprise a decorative layer applied to the radiant panel. The decorative layer may, for example, be impermeable to air, for example being leather.

[0074] The distribution electrodes 8 may, if desired, have more complex shapes, for example with one or more rounded elbows connecting rectilinear portions.

[0075] In the example described, all the inter-distance Ui values ​​of a group 15 are different. Alternatively, it is possible that some inter-distance values ​​of the same group are identical, and not all different.

[0076] The substrate can be a sheet or a canvas for example.

[0077] The contact electrodes 6 and their associated distribution electrodes 8 are arranged in the manner of nested combs.

[0078] In one variant, the heating structure is used in a passenger compartment component, being a passenger armrest, this structure being able to warm the arm of a passenger by thermal contact.

[0079] In the example described, the substrate 16 is extensible. In particular, the elements of the heating structure form an extensible assembly, namely the substrate 16, the resistive layer 4 and the contact electrodes 6 are extensible and flexible.

[0080] The contact electrodes 6 are formed by entangled wires, in particular woven or knitted, on a substrate 16 respectively woven or knitted.

[0081] The conductive wires forming the contact electrodes 6 are in contact with the resistive layer 4.

[0082] In another example of the invention, the substrate is a nonwoven. This nonwoven may comprise a mixture of polypropylene fibers and / or polyester fibers. Other fibers may be used, for example natural fibers.

[0083] Alternatively, the substrate 16 is a fabric, in particular with extensible yarns, or a knitted structure.

[0084] According to one aspect of the invention, the substrate may be a flexible plastic sheet or a foam such as TPU (thermoplastic polyurethane).

[0085] It has been represented on the figure 3 a heating structure 30 intended in particular to be installed inside a vehicle passenger compartment, this structure being a radiant panel, the heating structure comprising a set of tangled wires of which certain wires 31 form distribution electrodes 32, also called Busbar in English, and other tangled wires 33 form contact electrodes 34.

[0086] The substrate 35 on which the electrodes 32 and 34 are formed is here a knitted structure 35 which incorporates wires used as contact electrodes and the resistive layer 36 is placed on the surface. The resistive ink is assembled for example on the textile by lamination, screen printing or hot stamping and transfer.

[0087] The substrate 35 comprises at least one of the following wires: non-stretchable wires for the substrate, non-stretchable conductive wires for electrodes, single-strand or multi-strand copper wires, a copper conductive wire and non-conductive wires for reasons of mechanical strength or ease of manufacture.

[0088] The heating structure 30 comprises an electrical distribution circuit 39 comprising distribution electrodes 32 which transport the current from the connectors to the contact electrodes 34 which are in contact, for example, with a resistive layer.

[0089] The contact electrodes 34 and distribution electrodes 32 are for example made of copper wires.

[0090] When the substrate 35 is knitted, the stretchable characteristic can be obtained either by the arrangement of the knitted structure, namely by the knitting technique, or by the intrinsic stretchable character of the yarns used for knitting.

[0091] In particular, if the potential elongation of the conductive yarn is different from that of the main fibers of the knitted fabric, the end of each conductor must remain free to move inside or outside the knitted fabric.

[0092] Consider A as the number of contact electrodes 34 connecting to one of the distribution electrodes 32 and B as the number of wires used for each contact electrode, the distribution electrodes thus have AxB knitted wires. The knitted wires of the distribution electrodes are knitted to also form connection elements.

[0093] In order to have a continuous manufacturing process of the knitted or woven structure, it is possible to connect both sides of the contact electrodes 34 to the distribution electrodes 32 and then electrically neutralize a portion of these contact electrodes from the distribution electrode by cutting the wires of the contact electrodes by stamping them, as represented by the areas 41 on the figure 4 , or by integrating an electrical insulator into a zone 42 illustrated on the figure 5 , at the location where the electrical connection is to be interrupted. The figures 4 And 5 illustrate woven substrates 45.

[0094] It is possible to have a connector at the end of each contact electrode 36, or an external distribution electrode connecting all the contact electrodes together.

[0095] The wires used for the distribution electrodes are of larger diameter than the wires used to form the contact electrodes, or heating wires.

[0096] In the case of using heating wires, it is not mandatory to have a resistive layer, for example a resistive ink layer.

[0097] If several contact electrodes 34 are connected together to one of the distribution electrodes 32, as illustrated in the figure 3 , the connection between the distribution electrode 32 and the contact electrodes 34 can be achieved by integrating the distribution electrode into the weaving weft and the contact electrodes into the weaving warp or vice versa. By means of an alternating passage on both sides of the woven structure, the connection between electrodes is secured.

Claims

1. Heating structure (1) intended particularly to be installed inside a vehicle passenger compartment, said structure being particularly a radiant panel, the heating structure (30) comprising at least one resistive layer arranged to produce heat release when this layer (36) is traversed by an electric current, this structure further comprising a network of electrodes including a plurality of contact electrodes (34) arranged to be in electrical contact with the resistive layer to allow electric current to flow in this resistive layer, the contact electrodes (34) and the resistive layer are carried on a substrate (36) made of a flexible material capable of taking a predetermined shape by deformation, this substrate being particularly also extensible.

2. Heating structure according to the preceding claim, wherein the contact electrodes (34) are formed by interwoven, woven or knitted wires, on or in a respectively woven or knitted substrate.

3. Heating structure according to claim 1, wherein the substrate is a non-woven textile.

4. Heating structure according to any of the preceding claims, wherein the substrate is an extensible textile or extensible knit that incorporates wires used as contact electrodes and the resistive layer is placed on the surface.

5. Heating structure according to any of the preceding claims and claim 2, wherein several contact electrodes being connected together to a distribution electrode, the connection between the distribution electrode and the contact electrodes can be achieved by integrating the distribution electrode in the weaving weft and the contact electrodes in the weaving warp or vice versa.

6. Heating structure according to any of the preceding claims, wherein the contact electrodes (34) and distribution electrodes (32) are for example made of copper wires.

7. Component forming an element of a glove box or a vehicle door panel, comprising a heating structure according to any of the preceding claims.