FR3060470B1 - BODY PIECE OF A MOTOR VEHICLE HAVING A COATING FORMING AN ELECTRICAL SENSOR - Google Patents

Abstract

The object of the invention relates to a bodywork part (10) of a motor vehicle made of plastics material comprising at least one face (20) provided with a coating (30), characterized in that the part (10) comprises means (90) for connecting the coating (30) to a means (40) for measuring a variation of an electrical parameter related to the coating 30.

Description

The present invention relates to the field of the automotive industry, and more particularly to object detection systems of the electric sensor type, with contact (touch) or without contact (capacitive), for an opening of a motor vehicle. An electrical sensor is a sensor that detects a change in an electrical parameter.

There are known rear openings equipped with a motor intended to perform the opening and closing functions of the opening. Such openings can be equipped with object detection systems, with or without contact, such as anti-pinch devices or activation / opening / closing control devices.

In the case of an anti-pinch device, the object detection system makes it possible to avoid jamming of an object obstructing the opening, and at least one adjacent fixed element when the opening is closed. , in particular in the case where this object is a part of the body of a user.

In the case of a control device, the object detection system allows the opening of the opening by simple approach or by simple contact with a part of the opening.

Various types of object detection system are known, such as mechanical sensors of the switch type, resistive sensors, acoustic sensors, optical sensors, or even capacitive sensors.

The latter, capacitive sensors make it possible to detect, with or without contact, objects of all kinds, metallic or non-metallic. These sensors are based on the detection of a variation in capacity. The capacity between an active electrode of the sensor and the electrical potential of the earth is measured. An object placed between this active electrode and the electrical potential of the earth influences the value of this capacity.

The existing solutions constitute sensors manufactured independently of the part, and attached to the bodywork part. It follows: a complex architecture and a difficulty of installation because the space allocated in the vehicle is often very limited; a multiplicity of components to be assembled on the part; a need for many assembly operations, modifying conventional assembly lines.

In addition, by adding an element to the part, it is often necessary to restrict the detection area.

Finally, such sensors constitute unattractive visible elements. The invention aims to remedy these drawbacks by providing a part provided with a sensor using a coating of the part as a detection means.

Thus, the object of the invention relates to a motor vehicle body part made of plastic material comprising at least one face provided with a coating, as well as means for connecting the coating to a means for measuring a variation in an electrical parameter linked to the coating.

Thanks to such a part, it is possible to cover a larger detection area than most sensors.

This solution allows a higher level of integration than existing solutions: solution integrated into the coating when painting is finished, for example.

This solution is discreet because it does not consist of components to be mounted in an area visible to an operator.

Finally, this solution is compact because it only concerns a micro thickness between 10 and 50 micrometers of coating.

The part can also include one or more of the following characteristics, taken alone or in combination: the coating is capable of adhering to the plastic of the part, and has an electrical resistance of less than 20 kΩ at 300 K, preferably less than 5ku, more preferably less than 3kO; the coating contains electrically conductive charges, chosen alone or in combination from the following group of charges: graphite, metals, such as copper, silver, iron, indium, alloy of graphite and metal, carbon black; the coating contains more than 10% by weight of conductive filler, preferably between 20% and 60% by weight; the coating is chosen from the following group of coatings: a paint for bodywork; a primary; a base ; a varnish ; a metallic film; an electrically conductive substrate; an electrically conductive coating; the coating is covered with at least one other coating chosen from the following group of coatings: an anti-fouling protective varnish, a base, a paint varnish; the connection means are overmolded in the part or connected to an extended coating part on an invisible surface of the part; the part constitutes an opening of a motor vehicle; the face of the bodywork part covered by the coating and the measurement means define a tactile or capacitive sensor, said sensor constituting an anti-pinch system for the opening; the face of the bodywork part covered by the coating and the measurement means define a tactile or capacitive sensor, said sensor constituting a system for controlling the opening of the opening; the face of the bodywork part covered by the coating, is positioned in the area of the police plate of the tailgate-type opening; the measuring means is a means of measuring the capacitance between the coating and the electrical potential of the earth; the covering is covered with a plastic wall; the measuring means is a means of measuring a variation in electrical charges of the coating. The invention also relates to an assembly of a motor vehicle body part according to the invention and a means of measuring the capacity between the coating and the electrical potential of the earth. The invention will be better understood on reading the appended figures, which are provided by way of examples and have no limiting character, in which: FIG. 1 illustrates an example of a body part of a motor vehicle according to the invention; FIGS. 2A and 2B illustrate a detail of FIG. 1, in order to illustrate well the connection means between the coating and the measurement means; Figure 3 illustrates an example of a motor vehicle body part according to the invention, the coating of which forms a capacitive sensor; FIGS. 4A to 5B illustrate two exemplary embodiments, in which the positioning of the coating, and / or the covering of the coating are different, and form a capacitive sensor; - Figure 6A illustrates the skin of an opening constituting an example of a part according to the invention; FIG. 6B illustrates the lining of an opening constituting an example of a part according to the invention; 7 shows a section along A of Figure 6B, illustrating an anti-pinch system between the tailgate and the vehicle body, provided with a capacitive sensor; FIG. 8 illustrates an example of a part constituting a tailgate-type opening, mounted on a vehicle, in the closed position; FIG. 9 represents a section along A of FIG. 8, illustrating a system for controlling the opening of a tailgate, provided with a capacitive sensor; FIGS. 10A and 10B illustrate an exemplary embodiment of a touch sensor, in which the coating is covered with a varnish; Figure 11 shows a section along A of Figure 6B, illustrating an anti-pinch system between the tailgate and the vehicle body, forming a touch sensor; FIG. 12 represents a section along A of FIG. 8, illustrating a system for controlling the opening of a tailgate, provided with a touch sensor.

Referring now to FIG. 1, which illustrates an example of a body part 10 of a motor vehicle, made of plastic material, comprising at least one face 20 provided with a coating 30. The body part 10 comprises means for connection 90 of the coating 30 to a means 40 for measuring a variation of an electrical parameter linked to the coating 30.

FIGS. 2A and 2B illustrate a detail in FIG. 1, in order to illustrate well the connection means 90 between the coating 30 and the measurement means 40.

The coating 30 is a coating suitable for exterior bodywork parts made of plastic. Thus its formulation must in particular allow the coating 30 to be able to adhere to the plastic material (for example a treated polypropylene) of the part 10.

In the description, all the resistance values are values measured using an ITW Ransburg resistivity meter, using electrodes 25mm apart and positioned in the center of a rectangular plate of 200mm by 600mm. These measurements are carried out for coatings having a thickness of between 10 and 30 microns, at a temperature of 300K.

A primer conventionally used in an automotive bodywork paint chain has a resistance greater than 30kQ and less than 1ΜΩ.

According to the invention, a superconductive coating is used, that is to say having a low electrical resistance, making it possible to transport an electrical signal and transmit any alteration of the latter. Such a superconductive coating is defined as a coating having a resistance of less than 20kQ. According to the invention, a coating is used having a resistance of less than 20kQ, preferably less than 5kQ, more preferably less than 3kQ.

The superconductive coating 30 thus ensures better conductivity at the surface of the part 10.

According to one embodiment, the coating 30 is a coating enriched with electrically conductive pigments. The quantity of pigments is defined as a function of the conductivity of the pigment used, therefore as a function of the nature of the pigment. The fillers, conductive pigments, can be chosen alone or in combination from the following group of fillers: graphite in its different forms (tube, nanotubes, powders), metals such as copper, silver, iron, indium. .., in different forms (tube, powder, wire), an alloy of graphite and metal.

In general, the coating 30 comprises more than 10% by weight of pigments, preferably between 20% and 60% by weight.

The particle size of the pigments is preferably less than 25 micrometers. Such a particle size also makes it possible to obtain better dispersibility and to increase the distribution of the graphite pigments in the coating.

The coating 30 can be chosen from the following coatings: a paint for a bodywork part; a primer, that is to say the first coating applied to the surface of the part in a paint chain; a base, that is to say the coating applied to the primer in a paint chain; a varnish, that is to say the coating applied to the base in a paint chain; a metallic film; an electrically conductive substrate; an electrically conductive coating.

Thus, according to one embodiment, the coating 30 is a primer for an automobile body part enriched with electrically conductive pigments.

In a conventional painting process, a primer, a base and then a varnish are applied to obtain a painted surface. It will be recalled that the painting step of a plastic motor vehicle part generally includes a surface treatment step, followed by steps for applying three different coatings to the part. A first coating, called primer, has the function of favoring the grip on the part of the second coating, by improving the conductivity and the adhesion of the base (color layer). Thus, in a usual painting process, the primer constitutes a conductive coating serving to retain and attract the following coating layers by electrostatism. A second coating, called base, has the function of giving color to the room. Finally, a third coating, called varnish, has the function of protecting the base layer against external aggressions.

According to this embodiment, the coating 30 comprises: a primer; such a primer can comprise a polyurethane resin compound, one or two components, conductive fillers of the carbon black type and an organic solvent of the xylene, butyl acetate, butyl acetate glycol type ... the primer can also include a solvent for water base, glycol ether and / or pyrrolidone; loads of conductive pigments; such fillers can be chosen alone or in combination from the following group of fillers: graphite in its different forms (tube, nanotubes, powders), metals such as copper, silver, iron, indium, etc. in different forms (tube, powder, wire), graphite and metal alloy, carbon black.

According to one embodiment, the coating 30 can be applied to a conductive primer covering the face 20.

According to one embodiment, the coating 30 can be covered with one or more other coatings 100. These other coatings 100 can be chosen alone or in combination from the following coatings: an anti-fouling protective varnish, making it possible to avoid an erroneous detection of the made of the presence of a disturbing element such as rain, dirt ...; a base, that is to say the coating applied to the primer in a paint chain; a varnish, that is to say the coating applied to the base in a paint chain; preferably the varnish is an anti-fouling varnish, making it possible to avoid an erroneous detection due to the presence of disturbing element of the rain, dirt type;

According to one embodiment, the coating 30, or the succession of coatings, can also be covered with a plastic wall, allowing optimal protection of the coating 30.

FIGS. 2A and 2B illustrate a detail in FIG. 1, in order to illustrate well the connection means 90 between the coating 30 and the measurement means 40.

According to a first example (FIG. 2A), the connection means 90 “pass through” the thickness of the part 10. To do this, either a recess is provided during the molding of the part 10, or the recess is produced after molding and by machining. The connection means 90 are then passed through this recess in order to reach the coating 30. Another solution consists in overmolding a metal insert acting as connection means 90. This solution allows a simple assembly, and ensures good contact between the coating and the coating 30.

According to another exemplary embodiment (FIG. 2B), the connection means 90 come into contact with the coating 30 at the edge of the part. To do this, the coating 30 is extended to a non-visible area of the part 10, in order to come into contact with the connection means 90.

Capacitive type system

According to a first embodiment, illustrated by FIG. 3, the bodywork part 10 comprises means of connection 90 of the covering 30 to a means 40 for measuring the variation of the capacity between the covering 30 and the electrical potential of the earth 50. Such a means 40 is known to specialists.

The coating 30 forms the measuring electrode of a capacitive sensor 60, the electrical potential of the earth 50 forming the other electrode.

Indeed, the face 20 of the bodywork part covered by the coating 30, defines, with the measuring means 40 and the electrical potential of the earth 50, a capacitive sensor 60 which allows, by detecting a change in the capacitance of the sensor, detecting that a person or an object 70 is approaching the face 20 of the part. The measuring means 40 measure the variations in capacity between the earth and the measuring electrode, which is constituted by the covering 30. This capacity is modified for example when a part of a person's body 70 touches the covering 30, or comes close enough to the covering 30, the person 70 being itself capacitively connected to the ground by means of the ground.

According to this embodiment of the capacitive type, when a person or an object 70 approaches the covering 30, or when the covering 30 itself approaches a person or an object 70, this induces a variation of capacitance between the two electrodes (earth and the measuring electrode). This variation is detected by the measuring means 40 which sends an instruction to a control unit 80.

Examples of realization

Figures 4A to 5B illustrate two exemplary embodiments. In these figures, the axes X, Y and Z correspond to the usual orientation axes of motor vehicles: • X: longitudinal axis X (depending on the length of the vehicle), the X axis being oriented towards the rear of the vehicle; • Y: transverse axis Y (depending on the width of the vehicle); • Z: vertical axis Z (depending on the height of the vehicle).

According to the example of FIG. 4A, of which FIG. 4B represents the detail at the level of the connection, the coating 30 is applied to the non-visible face 20 of the part 10. The visible face is successively covered, and conventionally, by three coatings 100: a primer, a base and a varnish. According to this embodiment, the coating 30 is a conductive metallic film applied to the non-visible face of the external part 10. According to an advantageous example, the part 10 comprises on its non-visible face, facing the interior of the vehicle, a coating 110 forming an electromagnetic shield, in order to detect a variation in capacity only on one side of the room. This coating 110 also makes it possible to improve the sensitivity of the measurement, because in fact, the measurement is less subject to disturbances. The covering 110 is connected to the ground of the vehicle, in order to perfectly fulfill its role of electromagnetic shield.

According to the example of FIG. 5A, of which FIG. 5B represents the detail at the level of the connection, the coating 30 is applied to the visible face 20 of the part 10. The coating 30 is covered with two other coatings 100. According to this embodiment, the coating 30 is a primer covered with a base and a varnish. The base can be of the polyurethane type. Such a base can comprise, for example, a mono or bi-component polyurethane system, coloring pigments (for example TiO2), flakes (for example of the aluminum type) and fillers of the talc or calcium carbonate type. The varnish can be of the polyurethane type. Such a varnish can comprise, for example, a mono or bi-component polyurethane system, optionally with an acrylic resin. The latter can be an epoxy resin comprising an organic or aqueous solvent (water = glycol ether or pyrrolidone derivatives).

According to a particular embodiment of the invention, illustrated in FIGS. 6A and 6B, the capacitive sensor 60 constitutes an anti-pinch system for a door leaf of a motor vehicle.

FIG. 6A illustrates the skin 12 of the tailgate-type opening, which constitutes the visible face of the tailgate 10.

FIG. 6B illustrates the lining 14 of the tailgate-type opening, which constitutes the non-visible face of the tailgate 10.

The coating 30 is applied to the periphery of the lining, and to the visible face 20 of the lining (the other face is attached to the skin 12). This face constitutes an interior face, that is to say a face facing the interior of the vehicle, when the tailgate 10 is mounted and closed on the vehicle.

According to one example, the coating 30 is applied to the surface delimited by the interior contour of the sealing track and the exterior contour of the opening.

According to another example, the coating 30 is applied in the non-visible technical areas of the lining 14 which is delimited by an area going from the bottom of the upright to the bonding tracks of the window and the skin 12.

FIG. 7B represents a section along A of FIG. 6B, illustrating the anti-pinch system between the tailgate 10 and the body 120 of the vehicle.

As illustrated in FIG. 7B, the anti-pinch system can operate as a capacitive sensor, that is to say by remote detection, without contact with the person or object 70.

When the measurement means 40 detects a variation in capacity, it sends an instruction to a control unit 80 making it possible to stop or even reverse the actuation of the tailgate 10.

According to another particular embodiment of the invention, illustrated in FIG. 8, the capacitive sensor 60 constitutes a system for controlling the opening of a door leaf of a motor vehicle.

FIG. 8 illustrates a tailgate-type opening, mounted on a vehicle, in the closed position.

The coating 30 is applied in the police plate area; on a hidden side (near the lighting) seen from the rear of the vehicle. This face, generally not coated with paint, constitutes an external face, that is to say a face facing the outside of the vehicle, when the tailgate 10 is mounted and closed on the vehicle.

According to another example, the coating 30 is applied to a visible surface, in the form of decoration while fulfilling its technical function.

FIG. 9B represents a section along A of FIG. 8, illustrating the tailgate opening control system 10.

As illustrated in FIG. 9B, the opening control system can function as a capacitive sensor, that is to say by remote detection, without contact with the body part of a person 70.

When the measuring means 40 detects a variation in capacity, it sends an instruction to a control unit 80 making it possible to actuate the opening of the tailgate 10.

Touch-type system

According to a second embodiment, illustrated by FIG. 1, the bodywork part 10 comprises means of connection 90 of the covering 30 to a means 40 for measuring the variation of electrical charges of the covering 30. Such means 40 are known from specialists.

The coating 30 forms an electrical charge accumulation surface. When a part of the body of a person 70 touches the covering 30, a part of its loads is transferred to the person 70, or vice versa, being itself connected to the ground by the ground.

Thus, according to this tactile type operation, when a person 70 touches the coating 30, it modifies the electrical charges of the coating 30 which constitutes a touch sensor 60 with the measurement means 40. This modification is detected by the measurement means 40 which sends an instruction to a control unit 80.

Examples of realization

Figures 10A to 10B illustrate an exemplary embodiment. In these figures, the axes X, Y and Z correspond to the usual orientation axes of motor vehicles, as described above.

According to the example of FIG. 10A, of which FIG. 10B represents the detail at the level of the connection, the coating 30 is applied to the visible face 20 of the part 10. The coating 30 is covered with a second coating 100, such than an anti-fouling varnish. According to this embodiment, the coating 30 can be a conductive decoration film.

According to the particular embodiment of the invention, illustrated in FIGS. 6A and 6B, and already described, the anti-pinch system can function like a tactile sensor, that is to say by contact with a foreign body 70 ( hand, arm, head or object), as shown in Figure 11.

When the measurement means 40 detects a variation in the electrical charges of the covering 30, it sends an instruction to a control unit 80 making it possible to stop or even reverse the actuation of the tailgate 10.

According to the particular embodiment of the invention, illustrated in FIG. 8, and already described, the sensor 60 constitutes a system for controlling the opening of a door leaf of a motor vehicle.

As illustrated in Figure 12, the opening control system can function as a touch sensor, that is to say by contact with a part of the body of a person 70 (a hand, one or fingers).

When the measuring means 40 detects a variation in the electrical charges of the covering 30, it sends an instruction to a control unit 80 enabling the opening of the tailgate 10. The invention is not limited to the embodiments presented and other embodiments will be apparent to those skilled in the art. It is in particular possible that the part 10 constitutes a mobile spoiler, or aerodynamic flaps ("active shutter").

List of references 10: bodywork part 12: little of the tailgate-type door leaf 14: lining of the tailgate-type door leaf 20: face of the bodywork part 10 30: coating 40: means of measuring a variation d '' an electrical parameter linked to the coating 30. 50: electrical potential of the earth 60: capacitive sensor 60 70: person or object 80: control unit 80 90: connection means between the coating 30 and the measurement means 40 100: coating (s) covering the covering 30 110: covering forming an electromagnetic shield 120: body of the motor vehicle

Claims (14)

claims 1. Bodywork part (10) of a plastic motor vehicle comprising at least one face (20) provided with a coating (30), characterized in that the part (10) comprises connection means (90) of the coating (30) to a means (40) for measuring a variation of an electrical parameter linked to the coating 30 and in that the connection means (90) are overmolded in the part (10) or connected to a coating part (30) extended over an invisible surface of the part (10). 2. Piece (10) according to the preceding claim, in which the coating (30) is able to adhere to the plastic of the piece (10), and has an electrical resistance of less than 20kQ at 300K, preferably less than 5kQ, still preferably less than 3kQ. 3. Piece (10) according to the preceding claim, in which the coating (30) contains electrically conductive charges, chosen alone or in combination from the following group of charges: graphite, metals, such as copper, silver, iron, indium, alloy of graphite and metal, carbon black. 4. Piece (10) according to the preceding claim, wherein the coating (30) contains more than 10% by weight of conductive filler, preferably between 20% and 60% by weight. 5. Part (10) according to one of the preceding claims, in which the coating is chosen from the following group of coatings: a paint for bodywork; a primary; a base ; a varnish ; a metallic film; an electrically conductive substrate; an electrically conductive coating. 6. Part (10) according to one of the preceding claims, in which the coating (30) is covered with at least one other coating chosen from the following group of coatings: an anti-fouling protective varnish, a base, a varnish of painting. 7. Part (10) according to one of the preceding claims, constituting an opening of a motor vehicle. 8. Part (10) according to claim 7, wherein the face (20) of the part (10) of the body covered by the coating (30) and the measuring means (40) define a sensor (60) touch or capacitive , said sensor (60) constituting an anti-pinch system for the opening (10). 9. Part (10) according to claim 7, wherein the face (20) of the part (10) of the body covered by the coating (30) and the measuring means (40) define a sensor (60) touch or capacitive , said sensor (60) constituting a system for controlling the opening of the opening (10). 10. Part (10) according to claim 9, wherein the face (20) of the part (10) of bodywork covered by the coating (30), is positioned in the area of the police plate of the tailgate type opening (10). 11. Part (10) according to one of the preceding claims, in which the measuring means (40) is a means for measuring the capacity between the coating (30) and the electrical potential of the earth (50). 12. Part (10) according to the preceding claim, wherein the coating (30) is covered with a plastic wall. 13. Part (10) according to one of the preceding claims, in which the measuring means (40) is a means of measuring a variation in electrical charges of the coating (30). 14. Assembly of a bodywork part (10) of a motor vehicle according to one of the preceding claims and a means of measurement (40) of the capacity between the coating (30) and the electrical potential of the earth (50).