FASTENING ELEMENT

Abstract

The invention relates to a fastening element for fastening to a workpiece, said fastening element comprising at least a first workpiece element having a first opening and a second workpiece element having a second opening aligned with the first opening, wherein the fastening element has a first contact section having a first contact surface for contact with a region of the first workpiece element surrounding the first opening and a second contact section having a second contact surface for contact with a region of the second workpiece element surrounding the second opening, with the first contact section and the second contact section being connected to one another by means of a reshaping section, and with a rivet section extending from the second contact section in a direction facing away from the reshaping section. The invention further relates to a corresponding component assembly and to a method of manufacturing such a component assembly.

Claims

1. A fastening element for fastening to a workpiece, said fastening element comprising: at least a first workpiece element having a first opening and a second workpiece element having a second opening aligned with the first opening, wherein the fastening element has a first contact section having a first contact surface for contact with a region of the first workpiece element surrounding the first opening and a second contact section having a second contact surface for contact with a region of the second workpiece element surrounding the second opening, wherein the region of the second workpiece element faces the first workpiece element, and wherein the first workpiece element and the second workpiece element are arranged spaced apart from one another at least in the regions surrounding the first and second openings, with the first contact section and the second contact section being connected to one another by means of a reshaping section extending in a longitudinal direction of the fastening element, and with a rivet section extending from the second contact section in a direction facing away from the reshaping section.

2. The fastening element in accordance with claim 1, wherein at least one of the reshaping section and the rivet section is formed substantially symmetrically in a cross-section perpendicular to the longitudinal direction.

3. The fastening element in accordance with claim 1, wherein at least one of the reshaping section and the rivet section is arranged coaxially.

4. The fastening element in accordance with claim 1, wherein the second contact section is formed at an axial end of the reshaping section remote from the first contact section.

5. The fastening element in accordance with claim 1, wherein an outer periphery of the rivet section is smaller than an outer periphery of the reshaping section; and/or wherein a longitudinal extent of the rivet section is smaller than a longitudinal extent of the reshaping section.

6. The fastening element in accordance with claim 1, wherein a free end of the rivet section is chamfered.

7. The fastening element in accordance with claim 1, wherein the reshaping section has a reshaping device that is designed such that a force acting in an axial direction can be converted into a widening of the reshaping section.

8. The fastening element in accordance with claim 1, wherein at least one of the first contact section, the reshaping section, the second contact section, and the rivet section has a hollow space extending in the longitudinal direction.

9. The fastening element in accordance with claim 8, wherein the reshaping device is arranged in the hollow space of the reshaping section.

10. The fastening element in accordance with claim 7, wherein the reshaping device is arranged in a hollow space of the reshaping section extending in the longitudinal direction, and wherein the reshaping device comprises at least one step.

11. The fastening element in accordance with claim 8, wherein the hollow space is at least sectionally cylindrical and/or at least sectionally has an internal thread.

12. The fastening element in accordance with claim 8, wherein a wall thickness of the reshaping section varies in the longitudinal direction.

13. The fastening element in accordance with claim 1, wherein at least one of the first contact surface and the second contact surface is annular.

14. The fastening element in accordance with claim 1, wherein at least one of the first contact surface and the second contact surface has at least one feature providing security against rotation.

15. The fastening element in accordance with claim 1, wherein at least one of the first contact surface and the second contact surface comprises at least one recess.

16. The fastening element in accordance with claim 1, wherein at least one of an outer side of the reshaping section and an outer side of the rivet section has at least one feature providing security against rotation.

17. The fastening element in accordance with claim 1, wherein the fastening element is formed in one piece.

18. The fastening element in accordance with claim 1, wherein the fastening element is one of a nut element and a bolt element.

19. A component assembly, comprising: a workpiece that comprises at least a first workpiece element having a first opening and a second workpiece element having a second opening aligned with the first opening, wherein the first workpiece element and the second workpiece element are arranged spaced apart from one another at least in a respective region surrounding the first and second openings, and wherein the region of the second workpiece element faces the first workpiece element; and a fastening element having a first contact section having a first contact surface for contact with the region of the first workpiece element surrounding the first opening and having a second contact section having a second contact surface for contact with the region of the second workpiece element surrounding the second opening, wherein the first contact section and the second contact section are connected to one another by means of a reshaping section extending in the longitudinal direction of the fastening element, and wherein a rivet section extends from the second contact section in a direction facing away from the reshaping section, wherein the reshaping section is at least sectionally widened such that the first workpiece element is clamped between the first contact surface and a widened portion of the reshaping section, and wherein the rivet section is at least sectionally widened such that the second workpiece element is clamped between the second contact surface and a widened portion of the rivet section.

20. The component assembly in accordance with claim 19, wherein the second opening is smaller than the first opening.

21. The component assembly in accordance with claim 19, wherein the spacing of the region of the first workpiece element surrounding the first opening from the region of the second workpiece element surrounding the second opening is smaller than a longitudinal extent of the reshaping section before the fastening of the fastening element to the workpiece.

22. A method of manufacturing a component assembly, the component assembly comprising: a workpiece that comprises at least a first workpiece element having a first opening and a second workpiece element having a second opening aligned with the first opening, wherein the first workpiece element and the second workpiece element are arranged spaced apart from one another at least in a respective region surrounding the first and second openings, and wherein the region of the second workpiece element faces the first workpiece element; and a fastening element having a first contact section having a first contact surface for contact with the region of the first workpiece element surrounding the first opening and having a second contact section having a second contact surface for contact with the region of the second workpiece element surrounding the second opening, wherein the first contact section and the second contact section are connected to one another by means of a reshaping section extending in the longitudinal direction of the fastening element, and wherein a rivet section extends from the second contact section in a direction facing away from the reshaping section, wherein the reshaping section is at least sectionally widened such that the first workpiece element is clamped between the first contact surface and a widened portion of the reshaping section, and wherein the rivet section is at least sectionally widened such that the second workpiece element is clamped between the second contact surface and a widened portion of the rivet section, wherein the fastening element is introduced in the longitudinal direction of the fastening element first into the opening of the first workpiece element and then into the opening of the second workpiece element by means of a setting device by a setting movement that comprises at least a first movement phase and a second movement phase, wherein the rivet section cooperates with a die during the first movement phase in order to widen the rivet section, wherein the die is arranged at the side of the second workpiece element remote from the first workpiece element, and wherein a widening of the reshaping section is brought about during the second movement phase.

23. The method in accordance with claim 22, wherein the widening of the reshaping section and the widening of the rivet section take place offset in time and/or the first movement phase and the second movement phase are offset in time; and/or wherein the first movement phase and the second movement phase are coordinated with one another such that the widening of the reshaping section only starts after the widening of the rivet section has started or has been completed; and/or wherein the first movement phase and the second movement phase are coordinated with one another such that the widening of the reshaping section only starts after the second contact surface has been brought into contact with the region of the second workpiece surrounding the second opening; and/or wherein the first movement phase and the second movement phase merge into one another or overlap partly or completely; and/or wherein the first movement phase and the second movement phase are coaxial movements and/or have the same direction of movement; and/or wherein the setting device has a punch that projects into a hollow space of the reshaping section extending in the longitudinal direction and that cooperates with a reshaping device in order to widen the reshaping section; and/or wherein the reshaping device comprises at least one step that cooperates with the punch; and/or wherein the punch is moved relative to a section of the setting device cooperating with the first contact section in the longitudinal direction of the fastening element in order to bring about the second movement phase.

Description

[0046] The present invention will be explained in the following purely by way of example with reference to advantageous embodiments and to the enclosed drawings. There are shown:

[0047] FIGS. 1 and 2 a first embodiment of the fastening element in accordance with the invention in a perspective view in each case;

[0048] FIG. 3 the fastening element in accordance with the first embodiment in an axial view;

[0049] FIG. 4 the fastening element in accordance with the first embodiment in a longitudinal section or in a side view;

[0050] FIGS. 5 and 6 the process of inserting the fastening element in accordance with the first embodiment into a workpiece;

[0051] FIG. 7 the fastening element in accordance with the first embodiment in a state fixed to the workpiece (component assembly);

[0052] FIG. 8 the fastening element in accordance with the second embodiment in an axial view;

[0053] FIG. 9 the fastening element in accordance with the second embodiment in a longitudinal section or in a side view;

[0054] FIGS. 10 and 11 the process of inserting the fastening element in accordance with the second embodiment into a workpiece; and

[0055] FIG. 12 the fastening element in accordance with the second embodiment in a state fixed to the workpiece (component assembly).

[0056] FIGS. 1 and 2 show a first embodiment 10 of the fastening element in accordance with the invention. The element 10 has a central opening O and is—here by way of example—rotationally symmetrical about a longitudinal axis A and comprises a flange-like first contact section 12 and a second contact section 14. A reshaping section 16 extends between the contact sections 12, 14. A rivet section 18 extends from the contact section 14 in a direction that faces away from the reshaping section 16.

[0057] A contact surface 20 of the contact section 12 facing the reshaping section 16 serves for contact with a first component of a workpiece. The contact surface 20 is designed in an annular and substantially planar manner. Contrary to what is shown, it can also be provided with elevated portions and/or recesses that, on contact with said component, counteract a rotation of the element 10. A flange surface 11 is arranged at the side of the contact section 12 opposite the contact surface 20 and cooperates with a setting device, not shown, in a setting process.

[0058] The outer surface of the reshaping section 16 has a cylindrical base shape. If necessary, it can likewise be provided with features providing security against rotation that cooperate with walls of a hole in the first workpiece component. Such features providing security against rotation can, for example, be ribs (not shown) that extend in the axial direction of the reshaping section 16.

[0059] The contact section 14, which—like the contact section 12—is substantially annular, and a contact surface 22 for contact with a second component of the workpiece arranged spaced apart from the first component are arranged at the axial end of the reshaping section 16 remote from the contact section 12. To facilitate the introduction of the reshaping section 16 into a hole of the first component of the workpiece, the reshaping section 16 is provided with a (curved) chamfer 24. The contact surface 22 has an annular groove 26 that is bridged by ribs 27 extending in the radial direction. The ribs 28 are preferably uniformly distributed in the peripheral direction. It is understood that the features described with respect to the contact surface 22 can also be present at the contact surface 20 (and vice versa) if this should be necessary in the respective present application.

[0060] The rivet section 18 has a cylindrical base body 28 that merges into a curved end section 30 toward the free ends of the rivet section 18. The end section 30 can also have a slope. The end section 30 forms an introduction aid for inserting the rivet section 18 into a hole of the second workpiece component. The free end of the rivet section 18 is provided with a chamfer 32 around the opening O to facilitate the introduction of a die, not shown, into the rivet section 18.

[0061] FIG. 3 shows the element 10 in an axial view with a view of the contact surfaces 20, 22, whereby the rotationally symmetrical design of the element 10 can easily be recognized. In general, the contact surfaces 20, 22, the reshaping section 16, and/or the rivet section 18 can have other contours or cross-sections, e.g. oval or polygonal contours or cross-sections.

[0062] FIG. 4 shows a longitudinal section (left of the axis A) and a side view (right of the axis A) of the element 10. It can be recognized in the longitudinal section that the central opening O does not have a constant diameter. It has two steps S1, S2, whereby the diameter decreases, viewed from the contact section 12. For example, an internal thread can be provided in a region B below the step S2 and can serve for the connection to an object that should be coupled to the workpiece.

[0063] The opening O can also be considered as a combination of a plurality of mutually connected and mutually aligned hollow spaces of the sections 12, 14, 16, 18 that each do not necessarily have to have a constant diameter.

[0064] How the element 10 is fastened to a workpiece 34 will now be illustrated with reference to FIGS. 5 and 6. The workpiece 34 comprises two components 34A, 34B that, in the present example, are of different thicknesses and are arranged spaced apart in parallel from one another. It is understood that the components 34A, 34B can generally be of any desired design. In the context of the present invention, it is merely essential that they do not directly contact one another in regions around holes 36A, 36B in the components 34A and 34B that receive the element 10, but rather that a spacing D is present between the regions. The material of the components 34A, 34B can also be freely selected.

[0065] With the aid of a setting device 38 that engages at the flange surface 11 by means of a setting head 39 and that has a punch 40 that is fixedly connected to the setting head 39 and that projects into the opening O, the element 10 is first introduced into the hole 36A in a straight-line setting movement E. A conically shaped punch surface 42 contacts the step S1 in this respect. No deformation of the element 10 initially takes place.

[0066] Finally, the free end of the rivet section 18 penetrates into a gap between the margin of the hole 36B and a die 44 provided to reshape the rivet section 18. The introduction of the rivet section 18 into the hole 36B is promoted by the design of the end section 30. The chamfer 32 in turn facilitates the penetration of the die 44 into the lower end of the opening O.

[0067] As soon as the rivet section 18 comes into contact with the die 44 in the course of the setting movement E, its reshaping starts. It is bent over outwardly due to the shape of the die 44 and thus engages behind the workpiece 34B. On a progression of the setting movement E, the contact surface 22 comes into contact with the surface of workpiece component 36B facing the workpiece component 34A in a region around the hole 36B (see FIG. 6). The setting movement E therefore ultimately has the result that the rivet section 18 is supported on the die, while the contact surface 22 is pressed against the component 34B from above so that the region around the hole 36B is pressed into the annular groove 26.

[0068] However, the setting movement E not only results in a reshaping of the rivet section 18, but also in a widening of the reshaping section 16. When this starts, depends—in addition to the properties of the material of the element 10—also on its geometric design. As soon as the rivet section 18 namely cooperates with the die 44, a force occurs that counteracts the setting movement E. The conical punch surface 42 then cooperates with the step S1 and urges it outwardly on the progression of the movement E, whereby the reshaping section 18 forms a bulge. Due to this bulge 46, which can be easily seen in FIG. 6, a clamping connection is produced. In other words, the workpiece component 34A is clamped between the contact surface 20 and the bulge 46. The settling movement E is completed when the desired axial compression of the reshaping section 16 has been achieved and the contact surface 20 securely contacts the surface of the component 34A. The setting device 38 can then be removed.

[0069] The result of the above-described setting process, namely a component assembly 48 comprising the workpiece 34 having the components 34A, 34B and the element 10 reliably fastened thereto, is shown in FIG. 7. It can be recognized that the setting process did not result in a substantial change of the spacing D. An object can now be fastened to the workpiece 34 in a simple manner, for example, by means of a bolt. Due to the bulge 46 and the support of the reshaping section 16 on the workpiece component 34B, the element 10 acts as a stabilizing spacer.

[0070] Since the reshaping section 16 is compressed in the axial direction during the setting process, the spacing between the surfaces 20, 22 in an undeformed element 10 is slightly greater than the spacing D. This oversize corresponds to the axial compression. In general, it is also possible not to provide an oversize or even to provide an undersize if a reduction of the spacing D in the region of the holes 36A, 36B is deliberately intended to be achieved.

[0071] When the creation of the bulge 46 starts and how pronounced it is depends, among other things, on the geometry of the die, on the amplitude of the setting movement E, on the stability or the wall thickness of the reshaping section 16, and on the design of the step S1 and of the punch surface 42. These parameters are freely selectable and can be adapted to the respective present demands. The decisive factor is at what point in time the force directed against the setting movement E is so great that the radial force generated by the cooperation of the punch surface 42 with the step S1 exceeds the stability of the wall of the section 16 so that the widening of said section 16 starts. This point in time can be reached as soon as a reshaping of the rivet section 18 starts or a certain degree of reshaping of the rivet section 18 is achieved, for example, as soon as it sufficiently engages behind the component 34B so that an axial support is ensured. However, it can also be the point in time at which the contact surface 22 comes into contact with the surface of the component 34B. The element 10 can also be designed such that the two conditions occur substantially simultaneously. The reshaping of the reshaping section 18 can also only start when the reshaping of the rivet section 16 has already been substantially completed.

[0072] In other words: The setting process comprises at least two phases that are associated with the reshaping of the rivet section 18 (phase P1), on the one hand, and with the widening of the reshaping section 16 (phase P1), on the other hand. These two phases can be separated in time, can merge into one another or can at least partly overlap. In the above-described example, the phases P1, P2 overlap. The phase P1 starts before the phase P2 that, however, ends after the phase P1. In this respect, the setting movement E is a continuous linear movement in the present example. However, it is conceivable to provide a movement E that varies in time. The use of a punch 40 that is movable relative to the setting head 39 and that produces the deformation of the reshaping section 16 through its own movement, e.g. through an impact movement after the completion of a reshaping of the rivet section 18, is also conceivable.

[0073] A further embodiment 10′ of the fastening element in accordance with the invention will be described with reference to the following FIGS. 8 to 12. Externally, it resembles the element 10′ so that perspective views are omitted. There are also no decisive differences in the axial view (cf. FIG. 8).

[0074] It can, in contrast, be recognized from FIG. 9 that a slope Z (cf. the longitudinal section to the left of the axis A) is provided instead of the steps S1, S2 of the element 10. The element 10′ does not require a punch 40, as can be seen from FIGS. 10 and 11. The component assembly 48′ obtained by the setting process shown in FIGS. 10 and 11 is shown in FIG. 12.

[0075] The reshaping of the section 16 also takes place here if the force opposite to the setting movement E (e.g. generated by the reshaping of the rivet section 18) exceeds the stability of the wall of the reshaping section 16. A kink K between the otherwise cylindrical inner wall of the section 16 and the slope Z functionally forms a weakness zone that determines the start of the widening. The geometry of the slope Z (e.g. the inclination, the axial position, . . . ) and the wall thickness at a region disposed axially above the slope Z thus form a kind of reshaping device that produces the desired widening without an additional punch if a threshold value of an axial load is exceeded.

[0076] Since a punch can be dispensed with, the concept of the element 10′ is well suited for bolt elements. With said bolt elements, a bolt section of the element can project upwardly from the contact section 12 into a central opening O′ of the setting head 39.

REFERENCE NUMERAL LIST

[0077] 10, 10′ fastening element [0078] 11 flange surface [0079] 12, 14 contact section [0080] 16 reshaping section [0081] 18 rivet section [0082] 20, 22 contact surface [0083] 24, 32 chamfer [0084] 26 annular groove [0085] 27 rib [0086] 28 cylindrical base body [0087] 30 end section [0088] 34 workpiece [0089] 34A, 34B workpiece component [0090] 36A, 36B hole [0091] 38 setting device [0092] 39 setting head [0093] 40 punch [0094] 42 punch surface [0095] 44 die [0096] 46 bulge [0097] 48, 48′ component assembly [0098] A longitudinal axis [0099] O, O′ central opening [0100] D spacing [0101] S1, S2 step [0102] B threaded region [0103] E setting movement [0104] Z slope [0105] K kink