Flexible seal for motor vehicle and method of manufacturing the same

Abstract

The invention relates to a seal for a motor vehicle. Notably, the seal comprises a longitudinal profile (2) made of a rigid thermoplastic material and at least one element (3) made of an elastomeric material, the longitudinal profile (2) comprising a bottom (20) and two lateral longitudinal branches (21), wherein the longitudinal profile (2) comprises, over at least part of the length thereof, at least one bendable portion (25) having a corrugated structure, the corrugated structure portion (25) extending at least along one of two longitudinal connection regions (200), each extending between the base (20) and one of the two lateral branches (21), and wherein the corrugated structural portion (25) comprises a continuous series of corrugations without material interruption, the parallel planes of the parallel grooves of the plurality of corrugations being oriented perpendicular or substantially perpendicular to the longitudinal axis (X-X ') of the longitudinal profile (2).

Description

Technical Field

[0001] The invention relates to the field of motor vehicle equipment, such as in particular cars, trucks or tractors.

[0002] More specifically, the invention relates to a flexible seal for a motor vehicle, which is intended to be positioned at holes, for example in the body of the motor vehicle or on door panels (doors, hood and trunk lid), more specifically, at slots formed in these holes or on the door panels.

[0003] The invention also relates to a method for producing such a seal. Background Art

[0004] Such seals are known in the prior art and comprise a central metal frame around which a material, such as EPDM, is coextruded. Such a metal frame has an open structure of the "fishbone" type, which has a continuous solid and open structure.

[0005] However, new economic and ecological challenges related to reducing the weight of vehicles and the recyclability of their components require the development of lighter seals which can be recycled more easily, in particular by removing the original metal frame.

[0006] Additionally, such a seal must be flexible enough to be bent and mounted over a circular notch (radial clamp) in the vehicle body and must also be able to remain in the notch and not disengage from the notch over a wide range of vehicle operating temperatures.

[0007] A seal for motor vehicles is also known from document EP 3 409 522. However, this seal does not comprise a longitudinal profile with an open cross section, which is made of a rigid thermoplastic material and comprises corrugations whose concavities are oriented towards the interior of the longitudinal profile.

[0008] It can be seen that such a seal does not ensure both good flexibility in order to adapt to the shape of the support on which it is intended to be placed, and good clamping of this support in order to remain correctly thereon. Summary of the invention

[0009] The object of the present invention is therefore to propose a seal for a motor vehicle which is lighter and more easily recyclable than the seals of the prior art, which seal can be applied to slots, including slots with a smaller radius of curvature, and finally, which seal is able to clamp and remain on the slot within the normal operating range of the vehicle, that is to say typically between -30°C and 85°C.

[0010] To this end, the present invention relates to a flexible seal for a motor vehicle, which comprises a longitudinal profile configured to be positioned on a support (such as a groove) of the motor vehicle, and at least one element made of an elastomeric material, which element is selected from a longitudinal sealing lip and a support pad, the longitudinal profile having an open cross-section and comprising a bottom and two lateral longitudinal branches, the two lateral longitudinal branches extending from the bottom and on both sides thereof, respectively, so that the bottom and the two branches together form a clamp and define a longitudinal cavity opening opposite to the bottom, and the element made of an elastomeric material protrudes from the longitudinal profile toward the interior of the longitudinal cavity.

[0011] According to the invention, the longitudinal profile is made of a rigid thermoplastic material and comprises, over at least a portion of its length, at least one bendable portion having a corrugated structure, the corrugated structure portion comprising a continuous series of corrugations without material interruptions, the corrugations consisting of continuously alternating bridge members and joining sections, each bridge member having a back extended by two legs, the concave surface of the bridge member being oriented toward the interior of the longitudinal profile, and each joining section connecting the inner ends of the legs of the bridge member to the inner ends of the legs of the adjacent bridge member, the corrugated structure portion extending along at least one of the two longitudinal connecting areas, the two longitudinal connecting areas extending respectively between the bottom of the longitudinal profile and one of the two lateral branches and between the bottom and the other of the two lateral branches, and the parallel planes of the parallel grooves of the multiple corrugations being oriented perpendicularly or substantially perpendicularly to the longitudinal axis of the longitudinal profile.

[0012] Thanks to these features of the invention, there is a synergy between the two branches of the profile and the corrugations of the corrugated structure, which helps to increase the clamping effect of the profile and the overall retention of the seal when it is placed on a support, such as a notch, of a motor vehicle.

[0013] Furthermore, the corrugated structure gives the seal a bendable character both along the longitudinal axis of the profile and in the lateral direction, so that, for example, the seal can follow the curvature or sinusoidal shape of a support of a motor vehicle on which it is intended to be placed.

[0014] Additionally, the choice of materials makes the seals lighter and easier to recycle than those containing metal frames.

[0015] Finally, the element of elastomeric material protruding into the longitudinal cavity of the seal further enhances the retention of the seal when it is placed on the notch.

[0016] Other advantageous and non-limiting features according to the invention, considered alone or in combination:

[0017] The longitudinal profile comprises at least one portion, so-called "smooth" portion, without any corrugated structure.

[0018] The seal comprises, over at least a portion of the length of the longitudinal profile, an alternation of portions with a corrugated structure and portions with an open cross section and an alternation of portions with a smooth structure and portions with an open cross section.

[0019] The seal comprises, over at least part of the length of the longitudinal profile, a smooth portion extending over at least part of the width of the bottom, and a corrugated structure portion extending over the two lateral branches of the longitudinal profile.

[0020] The seal comprises, over at least a portion of the length of the longitudinal profile, a smooth portion extending over at least a portion of the height of at least one of the two lateral branches, and a corrugated structure portion extending over the width of the bottom.

[0021] - The at least one element made of elastomeric material is coextruded onto the longitudinal profile.

[0022] The longitudinal profile comprises at least one longitudinal damping tube made of elastomeric material, which projects outwards from the bottom or from one of the two lateral branches and which is coextruded on the longitudinal profile.

[0023] - The longitudinal profile is covered with a covering sleeve coextruded onto the profile, and wherein the longitudinal sealing lip and / or the support pad are made in one piece with the sleeve.

[0024] The covering sleeve further comprises at least one longitudinal damping tube protruding outwardly from the sleeve.

[0025] The depth of the corrugation at the free end of one of the two branches or at the free ends of both branches is equal to or greater than the depth of the same corrugation in the bottom section of the longitudinal profile.

[0026] The thickness of the thermoplastic material constituting the longitudinal profile is less in the two lateral branches than in the bottom and decreases towards the free ends of said branches.

[0027] The portion with the corrugated structure extends over the entire longitudinal profile and wherein the longitudinal profile is provided with outwardly protruding longitudinal ribs.

[0028] The outer surface of the back of the corrugations and / or the inner surface of the joining section is flat.

[0029] The invention also relates to a method for producing the above-mentioned seal.

[0030] According to the present invention, the method comprises the following steps:

[0031] - extrusion of a hollow initial longitudinal profile of closed cross section made of a rigid thermoplastic material,

[0032] - forming at least one bendable portion having a corrugated structure on at least a portion of the initial profile to obtain a corrugated profile,

[0033] - axially cutting the corrugated profile to obtain two longitudinal profiles with open cross-section,

[0034] - Coextrusion of at least one element made of elastomeric material, such as the longitudinal sealing lip or the support pad, to obtain said flexible seal.

[0035] Other advantageous and non-limiting features according to the invention, considered alone or in combination:

[0036] - The coextrusion of said at least one element made of elastomeric material is carried out simultaneously with the extrusion of the initial longitudinal profile.

[0037] The coextrusion of the at least one element made of elastomeric material is carried out on a longitudinal profile with open cross section after the cutting step. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features, objects and advantages of the present invention will appear from the following description, which is intended to be illustrative and not restrictive only and must be read in conjunction with the accompanying drawings, in which:

[0039] Figure 1 is a perspective view of a first embodiment of a seal for a motor vehicle according to the present invention.

[0040] Figure 2 It is along Figure 1 Detailed and longitudinal cross-sectional view of the seal taken along the cutting plane P2.

[0041] Figure 3 It is along Figure 1 Detailed and longitudinal cross-sectional view of the seal taken along the cutting plane P3.

[0042] Figure 4 is a perspective view of a first variant of the shape of the longitudinal profile of the seal according to the invention.

[0043] Figure 5 is a perspective view of a second variant of the shape of the longitudinal profile of the seal according to the invention.

[0044] Figure 6 is a perspective view of a third variant of the shape of the longitudinal profile of the seal according to the invention.

[0045] Figure 7 is a perspective view of a fourth variant of the shape of the longitudinal profile of the seal according to the invention.

[0046] Figure 8 is a perspective view of a second embodiment of a seal for a motor vehicle according to the present invention.

[0047] Fig. 9 is a perspective view of a third embodiment of a seal for a motor vehicle according to the present invention.

[0048] Fig.10 is a perspective view of a fourth embodiment of a seal for a motor vehicle according to the present invention.

[0049] Fig.11 is a perspective view of a fifth embodiment of a seal for a motor vehicle according to the present invention.

[0050] Fig.12 is a perspective view of a sixth embodiment of a seal for a motor vehicle according to the present invention.

[0051] Fig.13 is a perspective view of a seventh embodiment of a seal for a motor vehicle according to the present invention.

[0052] Fig.14 yes Fig.12 The seal shown is along Fig.12 A sectional view taken by cutting plane P14.

[0053] Fig.15 is a perspective view of an eighth embodiment of a seal for a motor vehicle according to the present invention.

[0054] Fig.16 yes Figure 1 A cross-sectional view of a seal.

[0055] Fig.17 is a schematic diagram showing a seal according to the present invention installed on a concave notch.

[0056] Fig.18 is a schematic diagram illustrating the first step of the experiment.

[0057] Fig.19 is a schematic diagram illustrating the second step of the experiment.

[0058] Fig. 20 is a graph illustrating the test results.

[0059] Fig.21 is a schematic diagram illustrating the different steps of an embodiment of a method for manufacturing a seal according to the invention. DETAILED DESCRIPTION

[0060] Now combine Figure 1 A first embodiment of a motor vehicle seal according to the present invention is described.

[0061] In this figure, it can be seen that the flexible seal 1 comprises a longitudinal profile 2 made of a rigid thermoplastic material and an element made of an elastomeric material 3 , such as a longitudinal sealing lip 30 .

[0062] The longitudinal profile 2 extends along a longitudinal median axis XX′. A longitudinal lip 30 extends along the same axis XX′ and projects along the profile.

[0063] The longitudinal profile 2 has an open cross section and comprises a base 20 and two lateral longitudinal branches 21 extending respectively from the base and from both sides of the base 20. These two branches 21 and the base 20 together form a fixture and thus define an open longitudinal cavity 22.

[0064] When the longitudinal profile 2 is positioned on a support, such as a notch, of a motor vehicle, this support, such as a notch, is received in the open longitudinal cavity 22 .

[0065] The profile 2 comprises two longitudinal connecting regions 200 extending respectively between the base 20 and one of the two branches 21 and between the base 20 and the other of the two branches 21 .

[0066] By “open cross-sectional profile” is meant that the open cavity 22 opens outwards via a hole 23 formed between two free ends 24 of the branches 21. In other words, the hole 23 is situated opposite the bottom 20.

[0067] exist Figure 1 In the exemplary embodiment shown, a longitudinal lip 30 projects from one of the two branches 21 , for example from the free end 24 thereof, towards the interior of the longitudinal cavity 22 .

[0068] Although not shown in the drawings, there may also be a second longitudinal lip 30 extending from the other of the two branches 21 , also protruding towards the interior of the longitudinal cavity 22 .

[0069] Finally, there may be a further longitudinal lip 30 extending from the bottom 20 towards the cavity 22 or from any point on the bottom 20 or on the branches 21 , but towards the outside of the profile 2 .

[0070] This lip or these lips participate in ensuring the airtightness when the seal 1 is in place on the notch of the motor vehicle. The lip 30 extending towards the inside of the cavity 22 also helps to keep the seal 1 on the notch.

[0071] Finally, the profile 2 comprises at least one portion having a corrugated structure 25 which extends at least along one of the two longitudinal connecting regions 200 and at Figure 1 In the exemplary embodiment of the present invention, the corrugated structure extends over the entire profile 2 .

[0072] As shown in the longitudinal section of the profile 2 Figure 2 and Figure 3 As can be seen better in the detailed view of , the corrugated structure portion 25 comprises a continuous series of corrugations 26 without interruptions in the material, that is to say without holes or openings passing through the profile 2 .

[0073] As in Figure 2 As can be seen in the figure, the series of corrugations 26 is composed of a continuous alternation of bridges 260 and junction sections 261. Each bridge 260 comprises a back 262 extended by two lateral legs 263, the concave surface of the bridge 2 being oriented towards the inside of the longitudinal profile 2, that is, towards the cavity 22. Each junction section 261 joins the inner end of a leg 263 of a bridge 260 to the inner end of a leg 263 of an adjacent bridge 260.

[0074] In the drawings, each bridge 260 has a U-shaped cross-section, and the two legs 263 of each bridge are parallel, however other shapes are possible, such as flared or bent legs.

[0075] Advantageously, the outer surface 264 of the back 262 is flat, such as Figure 2 This makes it easier to attach a coating that is coextruded with the profile 2, as will be described below.

[0076] The inner surface 265 of the engagement section 261 (that is to say the surface facing the cavity 22 of the profile) may be curved. However, advantageously, it may also be flat, although this is not shown in the figures.

[0077] Preferably, the parallel planes P4 of the different parallel grooves 266 of the corrugations 26 are oriented perpendicular or substantially perpendicular to the longitudinal axis XX′ of the profile 2. “Substantially perpendicular” means that the planes P4 form an angle of less than 10° with the axis XX′.

[0078] The depth H (or height) of the corrugation 26 measured between the outer surface 264 of the joining section 261 and the reference plane of the outer surface 267 , or more precisely the depth H (or height) of each bridge 260 , may be constant over the entire corrugated portion 25 of the profile 2 .

[0079] However, according to an advantageous variant embodiment, the depth of the corrugations 26 measured at the free end 24 of one of the two branches 21 or at the free ends of both branches 21 has a value H1 (see Figure 2 ), which is greater than the depth of the same corrugation 26 measured at the bottom 20 of the longitudinal profile 2 and which has a value H2 (see Figure 3 ). In other words, H1 is greater than H2.

[0080] Furthermore, the absence of material interruptions in the branches 21 and the presence of the corrugated portion 25 help prevent the two branches 21 from being separated from each other and promote the retention of the seal 1 on the notch F of the motor vehicle. As mentioned above, this effect is further enhanced when the depth H1 is greater than the depth H2. In fact, when the legs 263 are longer, the secondary moment of the bridge 260 increases.

[0081] However, it should be noted that in other embodiments, H2 may be greater than H1. The value of H1 may also be different in the two branches 21.

[0082] Preferably, the spacing P between one groove 266 and the next groove (see Figure 2 ) is constant. Also preferably, the pitch P is equal to or almost equal to the depth H (or height) of the corrugations 26.

[0083] Preferably, the pitch P is comprised between about 2 mm and 6 mm. Preferably, the depth H of the corrugations 26 is comprised between about 2 mm and 5 mm.

[0084] Advantageously, the height h of the lateral branch 21 (see Fig. 9 ) and the height H of the corrugation 26 (or more precisely the height H of each bridge-shaped member 260) is comprised between 2 and 20, more preferably between 3 and 8, or even better between 5 and 6.

[0085] Preferably, the height h of the lateral branches 21 of the profile 2 is comprised between approximately 10 mm and 40 mm.

[0086] Finally, preferably, the width L of the bottom 20 (see Fig. 9 ) is comprised between approximately 5 mm and 25 mm.

[0087] In combination Figure 1 In the exemplary embodiment described, it can be seen that the two branches 21 are straight and divergent (in other words, they are intended to move away from each other from the base 20 towards their free ends 24 ).

[0088] However, other shapes of the profile 2 are also conceivable. As a purely illustrative example, therefore, Figure 6In the embodiment in which two branches 21 are parallel to each other and perpendicular to the bottom 20, Figure 5 In the embodiment where the two branches 21 are straight and convergent, Figure 4 In the embodiment shown in FIG. 2 , the left branch 21 is straight and perpendicular to the bottom 20, while the right branch 21 is bent. In the latter case, the longitudinal profile 2 has an R-shaped cross section. This shape helps to further enhance the clamping effect of the two branches 21.

[0089] Finally, in Figure 7 In the embodiment in which the longitudinal profile 2 has a cross section with an open O-shape can be seen. In this case, the bottom 20 and the branches 21 are bent.

[0090] It is easily understood that many other cross-sectional shapes are conceivable for the longitudinal profile 2 without departing from the scope of the present invention, as long as the profile has an open cross-section as described above.

[0091] These different embodiments of the profile 2 being completely corrugated have particular application when the profile 2 must be able to bend in all planes.

[0092] According to other variant embodiments of the invention that will now be described, the longitudinal profile 2 comprises at least one portion having a corrugated structure 25 and at least one portion 27 referred to as “smooth”.

[0093] By "smooth portion" is meant a portion which does not have said corrugated structure. In other words, this portion 27 has only the thickness of the rigid thermoplastic material constituting the longitudinal profile 2 with an open cross section but which does not include the corrugations 26.

[0094] exist Figure 8 In the exemplary embodiment of , the longitudinal profile 2 comprises a smooth portion 27 extending over at least a portion of the width L of the base 20 and a corrugated structure portion 25 extending over the two lateral branches 21 .

[0095] This profile is used, for example, when a neutral fiber of the profile is needed only on the back (bent in the P3 plane), such as some trunk lid seals, for example, which may further include a damping tube on top of the bottom 20. Plane P3 corresponds to the median longitudinal plane of the profile 2 cutting the middle of the bottom 20.

[0096] exist Fig. 9In an exemplary embodiment of the longitudinal profile 2, the longitudinal profile 2 comprises a smooth portion 27 extending over at least a portion of the height h of at least one of the two lateral branches 21, here over the entire height h of the two lateral branches 21 but not over the connecting area 200; and also comprises a portion with a corrugated structure 25 extending over at least a portion of the width L of the bottom 20, here over the entire width L of the bottom 20 and over the area 200.

[0097] This profile is used, for example, when radial clamping is required only in the plane P2 or parallel to P2 , and the neutral fiber of profile 2 is then placed on one of the two branches (eg a hood seal). Plane P2 is located at the free end 24 of branch 21 .

[0098] exist Fig.10 In the exemplary embodiment of , the longitudinal profile 2 comprises an alternation of portions with a corrugated structure 25 and smooth portions 27. In this case, each portion with a corrugated structure 25 extends over the entire cross section of the profile, in other words over the branches 21 and the bottom 20, and each smooth portion 27 also extends over the entire cross section of the profile, in other words over the branches 21 and the bottom 20. The alternation of the different portions occurs over the length of the profile.

[0099] This type of arrangement allows, for example, to provide a portion with a corrugated structure 25 in a section of the seal 1 for matching the radius of curvature of the slot (for example at the corner of a vehicle door), and to provide a smooth portion 27 in a section of the seal 1 for opposing a straight section of the slot (for example a middle section of a vehicle door).

[0100] exist Fig.11 In the exemplary embodiment of the longitudinal profile 2 , the longitudinal profile 2 comprises a portion having a corrugated structure 25 on the bottom 20 and the branches 21 , and the profile 2 is further provided with longitudinal ribs 4 protruding towards the outside of the profile 2 .

[0101] The longitudinal rib 4 extends along the longitudinal axis XX′ of the profile 2. In the example shown, the longitudinal rib 4 is arranged on one of the two branches 21. The longitudinal rib may also be arranged along the bottom 20.

[0102] from Fig.12 and Fig.14 As can be seen in FIG. 2 , the profile 2 can also be provided with an outwardly protruding longitudinal damping tube 5 . The tube 5 extends parallel to the longitudinal axis XX′ of the profile 2 .

[0103] This tube 5 may be arranged along the lateral branch 21 or possibly along the bottom 20 .

[0104] This type of seal 1 is intended to be placed on a notch located in a hole in the body of the vehicle, opposite a door leaf, so that the tube 5 is oriented towards this leaf, such as a door, bonnet or trunk lid. Thus, when the door leaf is closed, the seal deforms and flattens the tube 5, which then performs its damping function.

[0105] Such a tube 5 may have a cross section of any shape. In the example shown, the cross section is substantially triangular.

[0106] Advantageously, the tube 5 is coextruded onto the profile 2 , for example simultaneously with the coextrusion of the sealing lip 3 .

[0107] One or more other elements made of elastomeric material may also be coextruded onto the profile 2, in this case in the form of support pads 51 protruding towards the cavity 22. These pads 51 strengthen the retention of the seal 1 on the support (notch).

[0108] In the embodiment just described, most of the corrugated structure 25 of the profile 2 is visible (except for the areas covered by the lip 3 or the tubes 5 or the uprights 51 ).

[0109] However, it is also possible to partially (e.g. Fig.12 or Fig.14 ) or completely (as shown in the embodiments of Fig.13 ) covers the longitudinal profile 2. Such a coating 6 can be used, for example, to change the aesthetic appearance of the longitudinal profile 2 by hiding it. The coating 6 is coextruded on the profile 2.

[0110] like Fig.15 As shown, according to another variant embodiment of the invention, it is possible to have a seal 1 in which the longitudinal profile 2 is covered with a covering sleeve 7. More precisely, the covering sleeve 7 is coextruded on the profile 2. In this case, the longitudinal sealing lip is integral with the sleeve 7 (made in one piece) and has the reference numeral 70. The longitudinal sealing lip extends parallel to the longitudinal axis XX′ of the profile 2 and can protrude at any point of the covering sleeve 7 towards the inside or outside thereof. If a support pad is present, it is also integral with the sleeve 7 (made in one piece).

[0111] Such a sleeve 7 can also be provided with a longitudinal damping tube.

[0112] In the case of using such a covering sleeve 7, the profile 2 is preferably constructed so that the outer surface 264 of each back 262 of the corrugation 26 is flat, and optionally also the inner surface 265 of the joining section 261 of the corrugation 26. The sleeve thus conforms better to these flat surfaces.

[0113] On the contrary, the use of such a tubular sleeve 7 allows avoiding having any material in the gaps between the two bridges 260 of the corrugations 26. This allows reducing the consumption of material used to make this sleeve 7, which gives the finished product (seal 1) a smoother appearance than that obtained with the use of a coating 6 in which the material is present in said gaps and, finally, a better flexibility than with the use of a coating 6.

[0114] Of course, depending on the intended use and positioning of the seal 1, the seals 1 just combined can be combined end to end over the entire length of the profile 2 as required. Figure 1 and Figures 8 to 15 A number of different embodiments are described. In all cases, the bendable portion 25 having a corrugated structure extends at least along one of the two longitudinal connecting regions 200, or even over both longitudinal connecting regions.

[0115] Finally, it is beneficial that Fig.16 As shown, which represents a cross section of a longitudinal profile 2, the thickness of the thermoplastic material constituting the profile 2 may vary. Thus, for example, the thickness may be less in the two lateral branches 21 than in the base 20 (the thickness e2 of the branch 21 is less than the thickness e1 of the base 20), and this thickness may decrease towards the free end of the branch 21 (the thickness e3 of the same branch measured at its free end is less than the thickness e2 measured in the middle section of the branch).

[0116] This thickness variation can be symmetrical or asymmetrical in the two branches.

[0117] This variation may allow the position of the neutral fiber of the seal 1 to be altered.

[0118] Material:

[0119] The profile 2 is made of a rigid thermoplastic material. "Rigid" refers to a structural material with a Young's modulus greater than 1500 MPa. For example, this material can be polypropylene (from the polyolefin polymer family), ABS (acrylonitrile butadiene styrene from the styrene polymer family), more or less filled with, for example, talc or glass fibers.

[0120] The other elements constituting the seal 1 (lips 30, 70, damping tube 5, support pad 51, longitudinal ribs 4, outer coating 6, sleeve 7) are made of a flexible elastomeric material, preferably a thermoplastic elastomer (TPE), such as vulcanized thermoplastic (VTP), thermoplastic styrene (TPS) or thermoplastic polyolefin (TPO). Porosity in these elements can be induced by using chemical or physical swelling agents (gas microcapsules). These flexible elements can be partially covered by coextrusion of a second lubricating thermoplastic elastomer TPE to reduce the friction coefficient with the surrounding parts.

[0121] Finally, the above elements, except the profile 2, may be made of an EPDM (ethylene-propylene-diene monomer) type elastomer. In this case, the seal 1 is less easily recyclable but retains its lightness and the economic advantages associated with the fact that no metal is used.

[0122] Positioning profile:

[0123] exist Fig.17 In the figure, the seal 1 is shown positioned on a notch F of a vehicle, which is concave and has a radius of curvature R. The notch F penetrates into the cavity 22. Although not shown in the figures, the notch F can also be convex. The corrugated portion 25 of the profile 2 allows the seal 1 to be easily bent to follow the radius of curvature R, which can be very small considering the good bending ability of the seal according to the invention.

[0124] Profile opening resistance test 2：

[0125] A comparative test of the opening resistance of the profile 2 was conducted by comparing different types of profiles.

[0126] from Fig.18 and Fig.19 It can be seen that each test profile A is arranged to straddle a support S, and the two sections of the support gradually separate to the left and right, respectively, and move from an initial position X0 to a final position X1. In the initial position, the profile is not subjected to force, while in the final position, the profile is subjected to force, so that the two branches of the profile tend to move away from each other.

[0127] The test results are as follows Fig. 20 , which shows the separation resistance F(X) at the two above-mentioned positions for a simple solid U-shaped profile (solid line result), a prior art profile in the shape of a fishbone (dashed line result) and finally a profile with a corrugated structure according to the invention (thick dashed line result), all three being considered to be the same rigid thermoplastic material.

[0128] It can be observed that the resistance generated when the two branches of the profile are open is about 2 times that of a simple U-shaped profile for the herringbone profile and about 6 times that of a simple U-shaped profile for the profile according to the invention.

[0129] These results demonstrate the synergy that exists between the clamp shape and the corrugated structure of the profile according to the invention and that this type of profile is particularly suitable for remaining fixed on a support (e.g. a notch) of a motor vehicle compared to other profiles made of the same material according to the prior art.

[0130] Manufacturing method:

[0131] Now combine Fig.21 An example of a possible embodiment of the manufacturing method is described. The method is implemented in an apparatus 9 .

[0132] First, an initial longitudinal profile 8 made of rigid thermoplastic material is extruded using an extruder 91. The profile formed is hollow and has a closed cross section. The extruder is fed by a reservoir 92 of rigid thermoplastic material.

[0133] Simultaneously, a coextrusion of at least one other element may be carried out using an extruder 91 fed by a reservoir 93 of elastomeric material. This other element is for example a sealing lip 30 or a support pad 51, since these elements may be added to the inside of the initial profile 8. In the same way, a coating made of a flexible thermoplastic material 6 may be added to the inside and / or outside of the profile 8 during this step.

[0134] The apparatus 9 also comprises a machine 94 for forming the corrugated portion 25. The initial profile 8 passes through the machine to form a portion with a corrugated structure 25 on at least a section of the profile. Thus, according to the above-described embodiment, a whole portion with a corrugated structure 25, or a series of portions with a corrugated structure 25 and a smooth portion 27 can be produced on a given profile length, and these different patterns can be repeated for mass production.

[0135] This forms a corrugated profile 8' which then passes through a cutting machine 95. As mentioned above, such a machine allows producing an axial cut of the profile with a closed cross section in order to obtain two longitudinal profiles 2 with an open cross section.

[0136] Each of these profiles 2 can then pass through a second die 96 supplied by one or more reservoirs 97, 97', 98, 98' of elastomeric material in order to co-extrude other elements required for use of the seal 1 on a vehicle, such as an outer lip, a damping tube 5, a coating 6, ribs 4 or a sheath 7.

[0137] In the case where all elements made of elastomeric material have been formed in the first die 91, there is no need to carry out a second coextrusion step in the second die 96. Conversely, it is possible to form all elements made of elastomeric material after the cutting step without carrying out a first coextrusion.

[0138] The direction of advancement inside the device 9 is indicated by arrow F.

Claims

1. A flexible seal (1) for a motor vehicle, the flexible seal comprising: a longitudinal profile (2) configured to be located on a support, such as a notch, of the motor vehicle; and at least one element (3) made of an elastomeric material selected from the group consisting of a longitudinal sealing lip (30, 70) and a support pad (51), The longitudinal profile (2) has an open cross section and comprises a bottom (20) and two lateral longitudinal branches (21) extending from the bottom (20) and on both sides thereof, respectively, so that the bottom (20) and the two branches (21) together form a fixture and define a longitudinal cavity (22) open opposite the bottom (20), The element (3) made of elastomeric material protrudes from the longitudinal profile (2) towards the interior of the longitudinal cavity (22), Features: The longitudinal profile (2) is made of a rigid thermoplastic material and comprises, over at least a portion of its length, at least one bendable portion having a corrugated structure (25), wherein the corrugated structural portion (25) comprises a continuous series of corrugations (26) without material interruptions, the corrugations (26) being composed of a continuous alternation of bridges (260) and joining sections (261), each bridge (260) having a back (262) extended by two legs (263), the concave surface of the bridge being oriented toward the interior of the longitudinal profile (2), and each joining section (261) connecting the inner end of a leg (263) of the bridge (260) to the inner end of a leg (263) of the adjacent bridge (260), The corrugated structure portion (25) extends at least along one of the two longitudinal connection areas (200), the two longitudinal connection areas extending respectively between the bottom (20) of the longitudinal profile (2) and one of the two lateral branches (21) and between the bottom (20) and the other of the two lateral branches (21), And wherein the parallel planes (P4) of the parallel grooves (266) of the plurality of corrugations (26) are oriented perpendicularly or substantially perpendicularly to the longitudinal axis (XX') of the longitudinal profile (2).

2. The seal for a motor vehicle according to claim 1, characterized in that: The longitudinal profile (2) comprises at least one portion (27), referred to as a "smooth" portion, without any corrugated structure.

3. The seal for a motor vehicle according to claim 2, characterized in that: The seal comprises, over at least a portion of the length of the longitudinal profile (2), an alternation of portions with a corrugated structure (25) and portions with an open cross section and an alternation of smooth portions (27) and portions with an open cross section.

4. The seal for a motor vehicle according to claim 2, characterized in that: The seal comprises, over at least a portion of the length of the longitudinal profile (2), a smooth portion (27) extending over at least a portion of the width (L) of the base (20), and a corrugated structure portion (25) extending over two lateral branches (27) of the longitudinal profile (2).

5. The seal for a motor vehicle according to claim 2, characterized in that: The seal comprises, over at least a portion of the length of the longitudinal profile (2), a smooth portion (27) extending over at least a portion of the height (h) of at least one of the two lateral branches (21), and a corrugated structure portion (25) extending over the width (L) of the base (2).

6. A seal for a motor vehicle according to any one of the preceding claims, characterised in that The at least one element (3) made of elastomeric material is coextruded onto the longitudinal profile (2).

7. A seal for a motor vehicle according to any one of the preceding claims, characterised in that The longitudinal profile (2) comprises at least one longitudinal damping tube (5) made of an elastomeric material, which projects outwards from the bottom (20) or from one of the two lateral branches (21), and wherein the longitudinal damping tube (5) is coextruded on the longitudinal profile (2).

8. The seal for a motor vehicle according to any one of claims 1 to 5, characterized in that: The longitudinal profile (2) is covered with a covering sleeve (7) which is coextruded onto the profile (2) and wherein the longitudinal sealing lip (70) and / or the support pad are made in one piece with the sleeve (7).

9. The seal for a motor vehicle according to claim 8, characterized in that: The covering sleeve (7) also comprises at least one longitudinal damping tube protruding outward from the sleeve (7).

10. A seal for a motor vehicle according to any one of the preceding claims, characterised in that The depth (H1) of the corrugation (26) at the free end (24) of one of the two branches (21) or at the free ends of the two branches (21) is equal to or greater than the depth (H2) of the same corrugation (26) in the bottom section (20) of the longitudinal profile (2).

11. A seal for a motor vehicle according to any one of the preceding claims, characterised in that The thickness of the thermoplastic material constituting the longitudinal profile (2) is less in the two lateral branches (21) than in the bottom (20) and decreases towards the free end (24) of the branch (27).

12. A seal for a motor vehicle according to any one of the preceding claims, characterised in that The corrugated structure portion (25) extends over the entire longitudinal profile (2), and wherein the longitudinal profile (2) is provided with outwardly protruding longitudinal ribs (4).

13. A seal for a motor vehicle according to any one of the preceding claims, characterised in that The outer surface (264) of the back (262) of the corrugation (26) and / or the inner surface (265) of the joining section (261) are flat.

14. A method for producing a flexible seal (1) according to any one of the preceding claims, characterized in that The method comprises the following steps: - extruding a hollow initial longitudinal profile (8) of closed cross section made of rigid thermoplastic material, - forming at least one bendable portion having a corrugated structure (25) on at least a portion of the initial profile (8) to obtain a corrugated profile (8'), - axially cutting the corrugated profile (8') to obtain two longitudinal profiles (2) with an open cross section, - Coextrusion of at least one element (3) made of elastomeric material, such as a longitudinal sealing lip (30, 70) or a support pad (51), to obtain said flexible seal (1).

15. The manufacturing method according to claim 14, characterized in that: The coextrusion of said at least one element made of elastomeric material is carried out simultaneously with the extrusion of said initial longitudinal profile (8).

16. The manufacturing method according to claim 14 or 15, characterized in that: The coextrusion of said at least one element made of elastomeric material is carried out on said longitudinal profile (2) with open cross section after said cutting step.

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