FASTENING ELEMENT, ASSEMBLY COMPRISING SAID FASTENING ELEMENT, FRONT END MODULE COMPRISING SAID FASTENING ELEMENT, AND METHOD FOR FASTENING SAID FASTENING ELEMENT

Abstract

Fastening element (10, 20, 30, 40) provided with a first end (16, 26, 36, 46) and a cavity (11) for receiving a complementary element therein, wherein the cavity (11) extends from the first end (16, 26) of the fastening element (10, 20, 30, 40) in an axial direction with respect to said fastening element (10, 20, 30, 40) towards a second end (17, 27, 37, 47), the fastening element (10, 20, 30, 40) having an outer wall which extends between the first end (16, 26, 36, 46) and the second end (17, 27, 37, 47), the outer wall comprising a wavy surface. The invention also relates to an assembly comprising an article and such a fastening element, and also to a front end module for a motor vehicle and to the fastening method comprising such a fastening element.

Claims

1. A fastening element comprising: a first end; a cavity configured to accept a complementary element, wherein the cavity extends from the first end of the fastening element in an axial direction with respect to said fastening element towards a second end; and an exterior wall which extends between the first and the second ends, the exterior wall comprising a wavy surface.

2. The fastening element as claimed in claim 1, in which the exterior wall comprises waves extending in the radial direction of the fastening element.

3. The fastening element as claimed in claim 1, wherein the exterior wall comprises waves extending in a direction that makes an acute angle with the axial direction of the fastening element.

4. The fastening element as claimed in claim 3, wherein the waves extend over a first part of the exterior wall in a first direction that makes an acute angle with the axial direction of the fastening element and over a second part of the exterior wall in a second direction that makes an acute angle with the axial direction of the fastening element.

5. The fastening element as claimed in claim 1, in which the exterior wall is also provided with a groove.

6. The fastening element as claimed in claim 1, wherein the fastening element is provided with a flange.

7. The fastening element as claimed in claim 1, wherein the fastening element is made at least partly from metal.

8. An assembly comprising an object and a fastening element as claimed in claim 1.

9. A front end module for a motor vehicle comprising an assembly as claimed in claim 8.

10. A method for fastening a fastening element as claimed in claim 1, in an object, comprising the following steps: positioning the fastening element in a mold designed to receive a material; closing the cavity with a closure element; and filling the mold with plastics material to fasten the fastening element in the plastics material within said object.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The object, subject matter and features of the present invention, together with the advantages thereof, will become more clearly apparent from reading the following description of preferred embodiments of a fastening element designed for an overmolding method according to the invention, which description is given with reference to the drawings in which:

[0032] FIG. 1 schematically shows the introduction of a plastics material containing fibers into a mold according to an overmolding method according to a first example of the prior art,

[0033] FIG. 2 schematically shows the introduction of a plastics material containing fibers into a mold according to an overmolding method according to a second example of the prior art,

[0034] FIG. 3 schematically shows a first embodiment of a fastening element according to the invention,

[0035] FIG. 4 schematically shows the introduction of a plastics material containing fibers according to an overmolding method using the fastening element of FIG. 3,

[0036] FIG. 5 schematically shows a perspective view of the fastening element of FIG. 3,

[0037] FIG. 6 schematically shows a second embodiment of a fastening element comprising a flange according to the invention,

[0038] FIG. 7 schematically shows the fastening element according to FIG. 6, with a first alternative form of said fastening element, and

[0039] FIG. 8 schematically shows the fastening element according to FIG. 6, with a second alternative form of said fastening element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The detailed description hereinafter is aimed at explaining the invention in a manner that is sufficiently clear and complete, notably using examples, but must not be considered to limit the scope of the protection to the particular embodiments and examples set out hereinafter.

[0041] FIG. 3 shows, in a face-on view, a first embodiment of a fastening element 10 according to the invention. The fastening element 10 according to FIG. 3 has a shape that is designed and optimized for fastening said fastening element 10 within an object (not shown) made of plastics material. Optimized fastening of the fastening element 10 according to FIG. 3 is achieved using an overmolding method. The fastening element 10 has a wavy exterior surface, shown in a radial direction with a concave part 13 and a convex part 14.

[0042] The fastening element 10 comprises a cavity 11, more particularly a tapping or thread, in the form of a screw thread, at its center and allowing a complementary element such as a threaded screw to be fastened. The cavity 11 and the concave part 13 are a determined minimum thickness 12 apart. The cavity 11 and the convex part 14 are a maximum thickness 15 apart. The minimum thickness 12 is determined to take into consideration the mechanical strength required for use of the fastening element 10.

[0043] One first advantage of the embodiment of the fastening element 10 according to FIG. 3 is explained with reference to FIG. 4. FIG. 4 schematically shows the introduction of a plastics material containing fibers 400 into a mold 100 during an overmolding method. A fastening element 10 according to the invention is fastened inside said mold 100. A cylinder 300 is positioned inside the fastening element 10 so as to avoid introduction of plastics material into said fastening element 10. Because the fastening element 10 has no flat surface, the flow of the plastics material containing fibers 400 occurs without said fibers 400 impacting on a flat surface. Thus, the integrity of the fibers 400 during introduction of the plastics material into the mold 100 is guaranteed. The end-product resulting at the end of the overmolding process therefore comprises a fastening element 10 positioned in an object made of plastics material and provided with fibers 400 that have not been impaired in any way as the plastics material was introduced into the mold 100.

[0044] Furthermore, the transfer of the forces exerted by the fastening element 10 toward the plastics material of the object to which said fastening element 10 is fastened is optimal. After the assembly made up of the object made of plastics material and of the fastening element 10 has been obtained, said assembly offers advantages by comparison with the assemblies produced in the prior art, as shown in FIGS. 1 and 2.

[0045] According to the present invention, if a force is exerted on the fastening element 10 in the radial direction, there is no concentration of said force. Thus, the force exerted on the fastening element 10 is transferred uniformly to the plastics material. As a result, by comparison with the fastening element 2 according to the prior art, the fastening element 10 according to the invention thus offers optimal breaking strength.

[0046] FIG. 5 shows a perspective view of the fastening element 10 according to the present invention. The fastening element 10 has, at its axial ends, two flat surfaces 16, 17. The outside of the fastening element 10 is formed by an exterior wall, or wavy or striated surface, which exhibits no flat surface between said flat surfaces 16, 17 and which extends in a radial direction of the fastening element 10. The fastening element 10 is provided with a groove 18 the purpose of which is to allow a determined quantity of plastics material to penetrate. Thus, when the fastening element is fastened within the plastics material, the presence of the groove 18 improves the pull-out strength resisting the pulling of said fastening element 10 out of the object made of plastics material in which said fastening element 10 is positioned.

[0047] FIG. 6 shows a second embodiment of a fastening element 20 according to the present invention. The fastening element 20 comprises a wavy exterior surface, as described in FIGS. 3, 4, 5. The fastening element 20 is provided with a groove 28 that has the same functionalities as the groove 18 as shown in FIG. 5. In order to improve the fastening of the fastening element 20 within an object made of plastics material, said fastening element 20 is provided with a flange 29. The flange 29 makes it possible to modify the diameter along the axial length of the fastening element 20. Thus, the pull-out strength of said fastening element 20 once it has been fastened within an object made of plastics material is improved.

[0048] According to the embodiment of the fastening element 10 as shown in FIGS. 3, 4, 5 and the embodiment of the fastening element 20 as shown in FIG. 6, the waves that form the radial exterior surface of the fastening elements 10, 20 are directed in a rectilinear direction between the surfaces that form the ends 16, 17 in the case of the fastening element 10, and the ends 26, 27 in the case of the fastening element 20.

[0049] According to an alternative embodiment 30, as shown in FIG. 7, the grooves 38 make an angle with the axial direction of the fastening element 30. Because the waves are inclined by a determined angle between the surfaces that form the ends 36, 37, this improves the fastening of the fastening element 30 in the plastics material and guarantees optimal breaking strength and pullout strength.

[0050] The fastening element 30 is provided with a groove 38 that has the same functionality as the groove 18 as shown in FIG. 5. In order to improve the fastening of the fastening element 30 within the object made of plastics material, said fastening element 30 is provided with a flange 39. The flange 39 makes it possible to alter the diameter along the axial length of the fastening element 30. Thus, the pull-out strength of said fastening element 30 resisting it being pulled out once it has been fastened within an object made of plastics material is improved.

[0051] According to an alternative embodiment 40 as shown in FIG. 8, the grooves 40 make an angle with the axial direction of the fastening element 40. Because the waves are inclined at two angles between the surfaces that form the ends 46, 47, that improves the fastening of the fastening element 40 in the plastics material and guarantees optimal breaking strength and pull-out strength.

[0052] The fastening element 40 is provided with a groove 48 that has the same functionality as the groove 28 as shown in FIG. 6. In order to improve the fastening of the fastening element 40 within an object made of plastics material, said fastening element 40 is provided with a flange 49. The flange 49 makes it possible to modify the diameter along the axial length of the fastening element 40. Thus, the pull-out strength of said fastening element 40 resisting its being pulled out after it has been fastened within an object made of plastics material is improved.