CAR BODY ELEMENT WITH CONTROLLED DEFORMATION

Description

[0001] The invention relates to controlled deformation bodywork elements of motor vehicles, for example deflector devices mounted on motor vehicles.

[0002] Among the deflectors found on a motor vehicle, one example is a movable deflector that can be mounted at the front of the vehicle under the front bumper. In any case, regardless of their positioning on the vehicle, such deflectors aim to reduce vehicle drag and consequently fuel consumption, particularly at high speeds, by diverting airflow in the opposite direction to the vehicle's forward motion.

[0003] At low speeds, the air deflector, which is usually a rigid blade with varying aerodynamic shapes and heights depending on the vehicle, is folded down under the front bumper to protect it from potential impacts with obstacles such as curbs. This position is therefore suitable for low-speed city driving or on roads with dips and bumps.

[0004] When the vehicle's speed reaches a threshold value, the blade is deployed, usually by a rotational movement, to oppose the airflow and thus reduce the vehicle's drag. The drag reduction can be, for example, on the order of 5% at a speed of 130 km / h. Alternatively, this deployment can be achieved by translation in a vertical plane, as described in US patent 8,702,152.

[0005] However, such a device has drawbacks.

[0006] First, deployment at relatively high speeds requires the use of actuation and holding devices in the deployed position. Such devices require significant power and are therefore energy-intensive. The movable deflector deploys by rotation, increasingly resisting a high-pressure airflow. Once deployed, the pressure exerted on the deflector is very high. The pressure distribution is such that the front face is under positive pressure, on the order of the dynamic pressure, and the rear face is under negative pressure, on the order of 30-40% relative to the front face. These two effects combine to create a substantial longitudinal force for deflection. For example, the pressure exerted on the deflector can reach 200 N at 130 km / h.

[0007] Furthermore, the movable deflector can encounter obstacles, even when the vehicle is traveling at high speed. The deflector, made of rigid material, and the entire system—that is, the actuator and clutch—can then be damaged. To prevent this, a rapid retraction and / or disengagement mechanism for the deflector is necessary.

[0008] French patent application FR 3 064 585 A1 describes a movable deflector for a motor vehicle comprising a deformable wall. However, it is also necessary to provide an actuation device to deploy this wall by deformation, located behind it. This device could be inflatable bladders, a system including hydraulic cylinders, or even movable roll bars. Such devices require the installation of a deformation element as well as a control and actuation system for this deformation element, which makes the assembly complex, relatively heavy, or bulky.

[0009] More generally, and for any bodywork element that can be deformed in a controlled manner, whether to improve the vehicle's aerodynamics (as described above), to locally modify the vehicle's shape for aesthetic purposes, or to increase resistance to low-amplitude impacts (for example, to protect a door from impacts), the use of a deformable panel requires a deformation device as described above. An example of such an application is described in application FR 3 075 721 A1, which discloses means of protecting a body panel comprising an elastically deformable skin. Documents EP 2 172 369 A1 and FR 3 039 805 A1 disclose devices for protecting a bodywork component comprising a movable part between a rest position and a protected position, with document FR 3 039 805 A1 disclosing the use of an elastically deformable panel.

[0010] US document 4 030 779 A describes a controlled-deformation body element according to the preamble of claim 1.

[0011] The invention aims in particular to provide a controlled deformation bodywork element that can be easily deployed and held in position while in the most compact and structurally simple state.

[0012] To this end, the invention relates to a controlled deformation body element for a motor vehicle comprising an elastically deformable main body, the main body comprising a network of channels, each channel being configured to be pressurized by a flow of compressed air in order to move the controlled deformation body element from a rest position to a deployed position, at least one air-controlled deformation body element stiffening element extending inside at least a portion of the channels.

[0013] Thus, a bodywork element is obtained that integrates, within the structure of an elastically deformable body, the means of deforming that body. Indeed, pressurizing the channels, which are therefore closed-section channels, allows the main body to deform from a rest position to an deployed position. In this deployed position, when the bodywork element is an air deflector, it diverts an airflow opposing the moving vehicle, or protects a body panel when the bodywork element is a protective device. It is therefore no longer necessary to provide a structure independent of the main body that deforms it when required.

[0014] The stiffening element, for its part, increases the bodywork component's resistance in its deployed position. Indeed, when the bodywork component is an air deflector, it allows the main body, in its deployed position, to resist tangential forces exerted on the sides of the deployed deflector by the aerodynamic air pressure generated by the vehicle's forward movement. This ensures proper deflection of the airflow and prevents deformation of the main body upon contact with this airflow. When the bodywork component protects a body panel, it withstands impacts of greater intensity than protective devices according to the prior art.More generally, and depending on the type of deformable bodywork element, the presence of the stiffening element can increase the resistance of the bodywork element in the deployed position, for example to a low-amplitude impact.

[0015] Depending on other optional features of the controlled-deformation body element, taken alone or in combination: The channel network is configured to allow deformation of the main body in a primary direction and more restricted deformation in directions perpendicular to the primary direction. This allows for precise control of the shape of the deformation-controlled body element, which only deforms in the desired direction. The main body is made of an elastomer, such as thermoplastic polyurethane, silicone, natural latex and mixtures thereof, or a mixture of styrene, ethylene-butylene styrene, and polypropylene. The channel network is a continuous network, with the main body including at least one air injection port within the channel network. This results in a relatively simple architecture for pressurizing the channel network.the main body comprises main channels and secondary channels connecting the main channels together, the stiffening member extending inside at least a part of the main and / or secondary channels; secondary parts of the stiffening member extending into secondary channels are configured to deform when the controlled-deformation body element moves from its rest position to its deployed position; the stiffening member is made of a material having a higher elastic modulus than the main body, preferably made of a material selected from steel, aluminum, glass fiber or talc-reinforced polypropylene, glass fiber-reinforced polyamide; the main body has a thickness of between 1 mm and 20 mm, preferably less than 10 mm, and even more preferably substantially equal to 5 mm;A gap is provided between the stiffening element and at least part of the wall of the channel containing it when the bodywork element is in its rest position. This ensures good passage of pressurized air, allowing the controlled-deformation bodywork element to move from its rest position to its deployed position; the stiffening element includes at least one depression configured to allow the passage of air between the stiffening element and an internal wall of at least one channel; and the main body comprises several channel networks configured to be controlled independently of each other, i.e., to be pressurized by compressed air flow independently of each other; the controlled-deformation bodywork element is an air deflector device.

[0016] The invention also relates to a method for manufacturing a bodywork element with controlled deformation according to the invention, comprising the following steps: manufacturing of the stiffening element, placement of the stiffening element in a mold, and overmolding of the main body around the stiffening element.

[0017] Such a process makes it possible to manufacture a controlled deformation bodywork element according to the invention in a relatively rapid manner.

[0018] Depending on other optional characteristics of the manufacturing process, taken alone or in combination: The stiffening element is molded. This allows for the design of all the components forming the deformation-controlled body panel by molding; the main body is molded using a material that does not adhere to the stiffening element. This ensures optimal passage of pressurized air through the channels along the stiffening structure when the deformation-controlled body panel moves from the retracted to the deployed position; and the overmolding of the main body around the stiffening element is followed by initial pressurization before the deformation-controlled body panel is used. This ensures optimal operation at the end of the manufacturing process, regardless of the shape of the stiffening structure or the materials used for molding the main body.

[0019] The invention also relates to a method for manufacturing a bodywork element with controlled deformation according to the invention, comprising the following steps: manufacturing of the stiffening element, molding of a first part of the main body including the channel network, the channels being open, placement of the stiffening element inside the channels of the first part of the main body remaining in the mold, and closing by molding the channels using a second part of the main body. Brief description of the figures

[0020] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which: [ Fig. 1 ] there figure 1 is a side view of a controlled-deformation bodywork element, here an air deflector device according to the invention in its deployed configuration, [ Fig. 2 ] there figure 2 is a front view of a controlled-deformation bodywork element, here an air deflector, according to the invention; [ Fig. 3 ] there figure 3 is a cross-sectional view along cutting plane AA of a portion of a controlled-deformation bodywork element according to a first embodiment of the invention, the controlled-deformation bodywork element being in its rest position, [ Fig. 4 ] there figure 4 is a cross-sectional view along a cutting plane AA of a portion of a controlled-deformation bodywork element according to the first embodiment of the invention, the controlled-deformation bodywork element being at the beginning of its deployment, [ Fig. 5 ] there figure 5 is a cross-sectional view along a cutting plane AA of a portion of a controlled-deformation bodywork element according to a second embodiment of the invention, the controlled-deformation bodywork element being in the rest position, [ Fig. 6 ] there figure 6is a cross-sectional view along a cutting plane AA of a portion of a controlled-deformation bodywork element according to the second embodiment of the invention, the controlled-deformation bodywork element being at the beginning of its deployment, [ Fig. 7 ] there figure 7 is a cross-sectional view along a cutting plane AA of a portion of a controlled-deformation bodywork element according to a third embodiment of the invention, the controlled-deformation bodywork element being in a rest position, [ Fig. 8 ] there figure 8 is a cross-sectional view along a cutting plane AA of a portion of a controlled-deformation bodywork element according to the third embodiment of the invention, the controlled-deformation bodywork element being at the beginning of its deployment, [ Fig. 9 ] there figure 9 is a top view of an air deflector device according to the invention, [ Fig. 10 ] there Figure 10is a top view of the stiffening device according to a first embodiment of the invention, [ Fig. 11 ] there figure 11 is a top view of the stiffening device according to a second embodiment of the invention, [ Fig. 12 ] there figure 12 is a cross-sectional view of a stiffening element installed in a part of a main body, the stiffening device having a first form, [ Fig. 13 ] there figure 13 is a cross-sectional view of a stiffening element installed in a part of a main body, the stiffening device having a second form, [ Fig. 14 ] there figure 14 is a cross-sectional view of the main body of the air deflector device according to the invention after overmolding of a second part of the main body. Detailed description

[0021] There figure 1This illustrates an example of a controlled-deformation body element. The description below will focus on an air deflector device 2, in this case a movable deflector that can be mounted at the front of the vehicle under the front bumper. As explained previously, this air deflector can also be placed in a different area of ​​the vehicle. For example, it could be a device mounted on a door or on a tailgate.

[0022] More broadly, this description applies to controlled-deformation body components other than air deflectors, for example, a door protection device comprising a controlled-deformation body. The technical principles described below, which apply to an air deflector 2, can also be applied to any other controlled-deformation body component. In other words, the detailed description below only describes, in a non-limiting manner, one example of a controlled-deformation body component (i.e., an air deflector 2).

[0023] The deployment and retraction direction of the air deflector device 2, which will be discussed later, depends on its positioning on the vehicle. For example, in the case of an air deflector device 2 mounted at the front of the vehicle under the front bumper 3, this direction corresponds to the downward vertical direction Z of the vehicle (according to conventional motor vehicle directions: longitudinal direction X, transverse direction Y, and vertical direction Z; see the reference mark on the figure 1 ).

[0024] There figure 1Figure 2 illustrates an air deflector device in its deployed position. In this position, its deployed shape deflects the relative airflow moving in the opposite direction to the vehicle's forward motion, represented here by arrow 5. This airflow deflection improves the vehicle's aerodynamics. The air deflector device 2 can be deployed when the vehicle reaches a certain speed in order to perform its function.

[0025] The deployment along a given direction, here the Z direction, corresponds to the main deformation. This is the greatest deformation of the air deflector device. Deformation along other directions, for example along the longitudinal X and transverse Y directions, is possible but less significant.

[0026] Furthermore, the deployment amplitude can vary. For example, the maximum deployment amplitude may exceed 10 times the thickness of the main body 4 of the air deflector device 2. Depending on factors such as vehicle speed, wind strength or direction, and road surface conditions, a greater or lesser deployment amplitude can be anticipated. This variation in deployment amplitude can be achieved by adapting the deployment mechanism described below. This greater or lesser deployment can also be adjusted based on the flexibility of the material forming the main body 4.

[0027] The air deflector device 2 can be deployed transversely to the direction of the airflow around the device, which can prevent increasing resistance to the airflow during rotational deployment. Indeed, depending on the direction of rotation of a movable air deflector device located at the front of the vehicle and under the front bumper, it can impede the airflow during its rotational deployment or retraction, particularly when the vehicle is traveling at potentially high speeds. For example, a movable air deflector device might deploy against an airflow when the vehicle is traveling at a speed exceeding 70 km / h.

[0028] In its deployed position, the first face of the air deflector device 2 (the one opposing, for example, an airflow) forms an angle between 30° and 90°, preferably between 50° and 80°, with a plane comprising the longitudinal axis X and the transverse axis Y of the vehicle. This angle deflects the air arriving at the first face of the air deflector device 2. A second face forms an angle between 0° and 90°, preferably between 0° and 45°, and even more preferably between 10° and 30°, with the plane described above. This angle is sufficient to maintain the airflow in contact with the air deflector device 2 as it passes from the first face to the second face and in contact with the vehicle at the rear of the air deflector device 2.

[0029] The air deflector device 2 comprises a main body 4 that is elastically deformable (according to the largest deformation described above) and includes a network of channels 6 (only some channels 6 are referenced in the figures), each channel 6 being configured to be pressurized by a flow of compressed air in order to move the air deflector device 2 from a rest position, or retracted position (for example, substantially flat), to an extended position. It is therefore understood that the channels 6 have a closed cross-section in order to be pressurized.

[0030] This main body 4 can be made from an elastomer, in particular thermoplastic polyurethane, silicone, natural latex and mixtures thereof, or from a mixture of styrene, ethylene-butylene styrene, and polypropylene. More generally, the material forming the main body has a lower elastic modulus than a stiffening element 8. For example, the main body 4 is made of an elastomer with an elastic modulus, measured at 23°C according to standard NFT 46-002, between 10 kPa and 200 MPa. Alternatively, a material with a hardness between 20 and 80 Shore A, preferably approximately 50 Shore A, can be chosen.

[0031] The channel network 6 is configured to allow deformation of the main body 4 in a first direction, with almost no deformation in planes perpendicular to the first direction. In the case of an air deflector device 2 mounted at the front of the vehicle under the front bumper 3, the main body 4 deploys in the vertical direction Z with restricted deployments in the longitudinal direction X and transverse direction Y.

[0032] The deformation of the main body 4 is achieved through the presence of at least one air injection orifice in the channel network 6. The number of air injection orifices can vary. Compressed air can be injected into the channel network 6 through the air injection orifice(s). For example, the channel network 6 can be a continuous network, with the main body 4 including at least one air injection orifice within the channel network. Alternatively, the channel network 6 can be formed from several independent portions, each portion including at least one air injection orifice.

[0033] The injection of compressed air thus allows a deformation of the main body 4, at least part of the channels 6 forming deformation plateaus (or contour lines) of varying heights following the direction of deployment of the air deflector device 2. The amplitude of deformation and the direction of deformation of the main body 4 is notably a function of the density of the channels 6 and their orientation, flexibility of the material forming the main body 4, as well as the pressure of the injected compressed air.

[0034] The macroscopic metric of the main body 4 in its deployed position differs from the macroscopic metric of the same main body 4 in its resting position. The "macroscopic metric of the main body 4" refers to the set of distances separating any two different points on the median surface defined within the main body 4, between its upper and lower surfaces. Thus, at least some distances between different points on the median surface have changed during the transition from the resting to the deployed configuration.

[0035] Furthermore, in the deployed position, the radius of curvature of an outer surface of the main body 4, measured with respect to each channel 6 adjacent to the outer surface, is greater than twice the size of the channel 6 adjacent to the outer surface. Thus, the channels 6 enable the stretching of the main body 4.

[0036] The main body 4 preferably has a thickness between 1 mm and 20 mm, preferably less than 10 mm, and even more preferably approximately 5 mm. The thickness is understood to be the smallest dimension of the main body 4 extending in the direction of deployment of the main body 4.

[0037] The main body 4, and in particular its shape, its properties, the materials forming it, the network of channels 6 (including their size within the main body 4) or its operation are described in application FR 3 084 010 A1. We are therefore talking about a baromorphic material (i.e. taking a different shape depending on the air pressure in the channels 6).

[0038] The air deflector device 2 further includes a stiffening element 8 of the air deflector device 2 extending inside at least a part of the channels 6.

[0039] As explained previously, the stiffening element 8 increases the resistance of the air deflector device 2 in its deployed position. This allows the main body 4, in its deployed position, to resist tangential forces exerted by an airflow opposing the vehicle's forward movement, ensuring proper airflow deflection and preventing deformation of the main body upon contact with this airflow. The presence of a stiffening element 8 within the channels reduces the air volume inside them. This allows for faster pressurization compared to channels without this structure and / or enables the use of a less powerful compressor.

[0040] As explained above, the stiffening element 8 can be made of a material with a higher elastic modulus than the material forming the main body 4. For example, it can be made of a material chosen from steel, aluminum, polypropylene reinforced with glass or talc fibers, or polyamide reinforced with glass fibers. The choice of material for the stiffening element 8, as well as its dimensions, particularly its thickness, are governed by the expected resistance performance of the air deflector device 2 to the tangential forces exerted by an airflow opposing the forward movement of a vehicle equipped with the air deflector device 2.

[0041] The figures in this application illustrate a scenario in which all the channels 6 include a stiffening element 8. This scenario will be described later. Alternatively, only some of the channels 6 may include a stiffening element 8. It is also possible for the air deflector device 2 to include several stiffening elements 8 extending into different portions thereof.

[0042] When compressed air is injected into the channel network 6, this leads to an expansion of the channels 6, as can be seen in the figures 4, 6 And 8 Compressed air passes around the stiffening element 8 to allow the deployment of the air deflector device 2.

[0043] In its resting state, the space occupied by the stiffening element 8 in the channels 6 can vary. In the illustrated examples, the channels 6 have a rectangular cross-section when the air deflector device 2 is in the retracted position, as do the portions of the stiffening element 8 (this shape varies slightly for the second embodiment illustrated in figures 5 and 6 (and described later). These shapes can obviously vary, for example by forming a polygon other than a rectangle, or by being circular or elliptical in section.

[0044] According to a first embodiment of the invention illustrated in the figure 3The stiffening element 8 occupies the entire volume of the channels 6. The forced passage of compressed air will lead to a separation of at least part of the internal walls 10 (only one internal wall is referenced per figure) of the stiffening element 8 in order to allow the deployment of the air deflector device 2.

[0045] According to a second embodiment illustrated in figures 5 and 6 and a third embodiment illustrated in figures 7 and 8 At least one gap can be provided between the stiffening member 8 and at least one internal wall 10 of at least one channel when the deflector device 2 is in the retracted position, preferably continuously along the channels 6. This ensures optimal passage of compressed air when deploying the air deflector device 2. As will be seen later, such configurations can be related to the manufacturing method of the air deflector device 2.

[0046] According to the second embodiment of the invention, the stiffening element comprises, on three of its faces (this number may vary, particularly depending on the shape of the stiffening element 8 or on the constraints related to its manufacture), at least one depression 9 allowing the passage of compressed air injected into the network of channels 6 (only a portion of the depressions 9 are referenced in the figures). The passage of compressed air will increase the size of the gap between the internal walls 10 of the channels 6, as can be seen in the figure 6 .

[0047] According to the third embodiment of the invention, the stiffening element 8 does not include a depression 9 but, more generally, a continuous gap is maintained between three inner faces of the channels 6 (this number may vary, particularly depending on the shape of the stiffening element 8 and the shape of the cross-section of the channels 6), even when the air deflector device 2 is retracted. The injection of pressurized air also accentuates this gap, as can be seen in the figure 8 .

[0048] There figure 9 illustrates a complete air deflector device 2 (i.e., including the main body 4 and the stiffening element 8), the Figures 10 and 11 illustrating, for their part, a stiffening element with or without a fixing interface.

[0049] The air deflector device 2 can therefore be fixed to a vehicle via at least one fixing interface 12 (four shown on the figures 9And 10 forming a fixing frame). This fixing interface 12 provides static reinforcement of the fixing at the edge of the main body 4. These fixing interfaces 12 may, for example, include one or more threaded through holes to allow the air deflector device 2 to be screwed onto a vehicle. Other conventional fixing methods may be used. These fixing interfaces 12 may or may not be connected to the stiffening element 8.

[0050] The main body 4 may include main channels, which are the channels allowing the deformation of the latter described above (i.e. baromorphic deformation), and secondary channels, or inter-channels, connecting the main channels together, and allowing for example the passage of compressed air from one main channel to another (i.e. connecting the main channels of the same channel network 6).

[0051] The stiffening element 8 can extend inside at least part of the main and / or secondary channels. In the example illustrated on the figure 9 The stiffening member 8 is made in one piece extending into all the main and secondary channels of the main body 4. It would be possible to vary the implantation of the stiffening member(s) 8 in the channels, for example by using several stiffening members 8 extending into the main channels without having a stiffening member 8 in the secondary channels.

[0052] The main channels dilate during the injection of compressed air, as illustrated in the figures 4, 6 And 8 However, apart from this expansion, they do not deform. The main parts 14 (only a part referenced on the figures 9 to 11The stiffening element 8 therefore does not deform. The secondary channels, however, can stretch during the deployment of the air deflector device 2. Consequently, the secondary parts 16 (only a part referenced on the figures 9 to 11 ) of the stiffening element 8 can deform with the secondary channels. They can for example adopt a folded shape comprising several segments extending into secondary channels themselves comprising a folded shape with several segments, the secondary channels and the secondary parts 16 of the stiffening element 8 unfolding during the deployment of the air deflector device 2.

[0053] The cross-section of the secondary channels may be reduced during the deployment of the air deflector device 2 due to a possible stretching during the deployment of the air deflector device 2. It is therefore possible to dimension the secondary parts 16 of the stiffening element 8 so that they do not disrupt the passage of compressed air in such a case, or it is possible to consider leaving the secondary channels without a stiffening element 8.

[0054] According to one embodiment, the controlled-deformation body element 2 comprises a main body 4 equipped with several (at least two) independent channel networks 6, i.e., the networks are configured to be pressurized by compressed air flow independently of each other. Thus, each channel network 6 can be controlled individually, separately.

[0055] For example, it is possible to pressurize the channels of a first network by a first flow of compressed air, thus deforming a first part of the main body 4. Then, independently, but possibly at the same time, it is possible to pressurize the channels of a second network by a second flow of compressed air, thus deforming a second part of the main body 4.

[0056] Thus, different variants of the shape of the bodywork element 2 can be obtained by alternately activating one or more networks of independent (pneumatically) channels.

[0057] Regarding the manufacturing processes of the air deflector device 2, two will be described later.

[0058] According to a first manufacturing method for the air deflector device 2, the first step consists of manufacturing the stiffening element 8. The manufacturing method may vary depending on the material chosen for its production. The stiffening element 8 can, for example, be molded if it is made of plastic, for example, using the plastics illustrated above. The connection interfaces 12 can also be molded.

[0059] Once the stiffening member 8 has been manufactured, it is placed inside a mold in order to overmold the main body 4 onto the stiffening member 8.

[0060] During this overmolding process, it is possible to use a material to form the main body 4 that does not adhere to the material forming the stiffening element 8. For example, it is advantageous to make the main body 4 out of silicone because this material has the advantage of adhering to very few other materials. The following material pairs can also be used: a main body 4 of thermoplastic polyurethane and a stiffening element 8 of talc-filled or glass fiber polypropylene, a main body 4 of thermoplastic polyurethane and a stiffening element 8 of glass fiber-filled polyamide, a main body 4 of silicone and a stiffening element 8 of glass fiber-filled polypropylene, a main body 4 of silicone and a stiffening element 8 of glass fiber-filled polyamide, a main body 4 made of a styrene ethylene-butylene styrene and polypropylene mixture, and a stiffening element 8 of glass fiber-filled polyamide.

[0061] Alternatively or in addition to the use of a material that does not adhere to the stiffening element 8, it is possible to mold the latter using a material containing an additive to prevent adhesion, or to carry out an anti-adherent surface treatment after the manufacture of the stiffening element 8.

[0062] The advantage of molding the stiffening element 8 is that it allows for the molding of all the elements forming the air deflector device 2. For example, it is possible to produce the stiffening element 8 and the main body 4 within the same mold. This could be, for example, a mold comprising the same die but two punches to mold the stiffening element 8 and then the main body 4. Other processes known to those skilled in the art, which allow for molding the stiffening element 8 and then overmolding the main body 4, can be implemented.

[0063] Alternatively, or in addition to using a material that does not adhere to the stiffening element 8, a stiffening element 8 can be manufactured comprising one or more depressions 9. These depressions ensure the passage of compressed air between the stiffening element 8 and the internal walls 10 of the channels 6. In particular, this passage will allow the main body 4 to be separated from the stiffening element 8 in the event of adhesion between them due to the nature of the materials used in their construction. Advantageously, the depressions 9 are sized taking into account the viscosity of the material used to mold the main body 4, thus preventing the viscosity from entering the depressions 9 during overmolding and trapping air there.

[0064] Advantageously, the overmolding of the main body 4 is followed by an initial pressurization before use of the air deflector device 2. This is a first injection of compressed air to ensure the optimal passage of compressed air in the channels 6, or even to carry out the initial separation of the stiffening element 8 and the main body 4 explained above.

[0065] According to a second manufacturing process for the air deflector device 2, the first step still consists of manufacturing the stiffening element described above.

[0066] In parallel with this manufacturing process, a first part 18 of the main body 4 is molded. This first part includes the network of open channels 6, that is to say, accessible (or open) in order to place the stiffening element(s) 8 into them. The latter is then placed in the channels 6 to obtain the intermediate structure 22 visible on the figure 12 .

[0067] There figure 13 illustrates a variant of the figure 12 in which a stiffening element 8 comprising depressions 9 is placed in the first part 18 of the main body 4. In general, this manufacturing process allows the implementation of the three embodiments illustrated in figures 3 to 8 For example, it would be possible to design channels 6 with a cross-section larger than that of the various parts of the stiffening element 8 so that a constant clearance is maintained between the latter and the internal walls 10 of the channels 6 (third embodiment illustrated in figures 7 and 8 ).

[0068] After placement of the stiffening element(s) 8 in the channels 6, a second part 20 of the main body 4 can be molded onto the intermediate structure 22 to close the channels 6. The second part 20 of the main body 4 can also be attached to the first part 18 of the main body 4. The figure 14 includes two dotted lines illustrating two different separations between the first part 18 of the main body 4 and the second part 20 of the main body 4. List of references

[0069] 2: Controlled deformation body element / air deflector device 3: Front bumper 4: Main body 5: Airflow direction 6: Channels 8: Stiffening element 9: Recesses 10: Channel inner walls 12: Mounting interface 14: Main parts of the stiffening element 16: Secondary parts of the stiffening element 18: First part of the main body 20: Second part of the main body 22: Intermediate structure

Claims

1. Controlled-deformation bodywork element (2) for a motor vehicle, comprising an elastically deformable main body (4), the main body (4) comprising a network of channels (6), each channel (6) being configured to be pressurized by a flow of compressed air from a compressor so as to move the controlled-deformation bodywork element (2) from a rest position to a deployed position, characterized in that at least one stiffening member (8) of the controlled-deformation bodywork element (2) extends inside at least a portion of the channels (6).

2. Bodywork element (2) according to claim 1, wherein the network of channels (6) is configured to allow deformation of the main body (4) in a first direction and a more limited deformation in directions perpendicular to the first direction.

3. Bodywork element (2) according to any one of the preceding claims, wherein the network of channels (6) is a continuous network, the main body (4) comprising at least one air injection orifice into the network of channels (6).

4. Bodywork element (2) according to any one of the preceding claims, wherein the main body (4) comprises main channels and secondary channels interconnecting the main channels, the stiffening member (8) extending inside at least a portion of the main and / or secondary channels.

5. Bodywork element (2) according to claim 4, wherein secondary portions (16) of the stiffening member (8) extending into secondary channels are configured to deform when the bodywork element (2) moves from its rest position to its deployed position.

6. Bodywork element (2) according to any one of the preceding claims, wherein the stiffening member (8) is made of a material having an elastic modulus greater than that of the main body (4), preferably of a material selected from steel, aluminum, glass-fiber- or talc-filled polypropylene, or glass-fiber-filled polyamide.

7. Bodywork element (2) according to any one of the preceding claims, wherein the main body (4) has a thickness between 1 millimeter and 20 millimeters, preferably less than 10 millimeters, and more preferably substantially equal to 5 millimeters.

8. Bodywork element (2) according to any one of the preceding claims, wherein a clearance is provided between the stiffening member (8) and at least one internal wall (10) of at least one channel (6) when the bodywork element (2) is in the rest position.

9. Bodywork element (2) according to the preceding claim, wherein the stiffening member (8) comprises at least one recess (9) configured to allow air to pass between the stiffening member (8) and an internal wall (10) of at least one channel (6).

10. Bodywork element (2) according to any one of the preceding claims, wherein the main body (4) comprises several channel networks (6) configured to be controlled independently of one another.

11. Bodywork element (2) according to any one of the preceding claims, wherein the bodywork element (2) is an air deflector device (2).

12. Method of manufacturing a controlled-deformation bodywork element (2) according to any one of the preceding claims, comprising the steps of: - manufacturing the stiffening member (8), - placing the stiffening member (8) in a mold, and - overmolding the main body (4) around the stiffening member.

13. Manufacturing method according to claim 12, wherein the stiffening member (8) is molded.

14. Manufacturing method according to claim 12 or 13, wherein the main body (4) is molded from a material that does not adhere to the stiffening member (8).

15. Manufacturing method according to any one of claims 12 to 14, wherein the overmolding of the main body (4) around the stiffening member (8) is followed by an initial pressurization before use of the controlled-deformation bodywork element (2).

16. Method of manufacturing a controlled-deformation bodywork element (2) according to any one of claims 1 to 11, comprising the steps of: - manufacturing the stiffening member (8), - molding a first portion (18) of the main body (4) comprising the network of channels (6), the channels (6) being open-ended, - placing the stiffening member (8) inside the channels (6) of the first portion (18) of the main body (4) while it remains in the mold, and - closing the channels (6) by molding a second portion (20) of the main body (4).