Fastening element for friction welding and method for friction welding a fastening element onto a planar workpiece

Abstract

A fastening element for friction welding onto a planar workpiece includes a nut head, a through-bore extending at least locally within the nut head, a friction welding face on one end side of the nut head, and a cutting device for introducing a drilled hole into the workpiece on the one end side of the nut head having the friction welding face.

Claims

1. A fastening element for friction welding onto a planar workpiece, the fastening element comprising: a nut head having an end face; a welding component attached to the end face of the nut head and defining a friction welding face; a through-bore extending at least locally within the nut head; and a shaft portion extending from the end face of the nut head and including a cutting device configured to drill a hole into the workpiece to allow the shaft portion to be inserted into the hole, wherein the shaft portion has an elongated configuration and has a length greater than a diameter of the shaft portion, the welding component being made of a material different from that of the nut head and configured to be melted when the welding component frictionally and rotationally contacts the planar workpiece during rotation of the fastening element.

2. The fastening element according to claim 1, wherein the shaft portion extends from the end face of the nut head in a direction away from the nut head and along a longitudinal central axis of the nut head and has at least one cutting element.

3. The fastening element according to claim 2, wherein the shaft portion includes a free end portion opposite the nut head, wherein the at least one cutting element is on the free end portion of the shaft portion.

4. The fastening element according to claim 3, wherein the shaft portion is a hollow cylinder arranged concentrically with the longitudinal central axis of the nut head.

5. The fastening element according to claim 4, wherein the shaft portion has an end edge in the shape of a ring or a ring segment opposite the nut head, wherein multiple cutting elements are provided at least locally on the end edge.

6. The fastening element according to claim 1, wherein at least one cutting element in the form of a saw tooth or a cutting segment is arranged on the cutting device.

7. The fastening element according to claim 1, wherein the friction welding face is in the form of a circular ring surrounding the shaft portion and the cutting device.

8. The fastening element according to claim 7, wherein the friction welding face surrounds the shaft portion and the cutting device concentrically.

9. The fastening element according to claim 1, wherein the nut head and the cutting device are one piece.

10. The fastening element according to claim 1, wherein the through-bore extends continuously through the nut head and the cutting device.

11. The fastening element according to claim 10, wherein the through-bore has an internal thread.

12. A fastening element for friction welding onto a workpiece, the fastening element comprising: a nut head having an end face; a welding component attached to the end face of the nut head and defining a friction welding face; a shaft portion extending from the end face of the nut head; a cutting device disposed at the shaft portion and configured to drill a hole into the workpiece to allow the shaft portion to be inserted into the hole; and a through-bore extending within the nut head and the shaft portion, wherein the shaft portion has an elongated configuration and has a length greater than a diameter of the shaft portion, the welding component being made of a material different from that of the nut head and configured to be melted when the welding component frictionally and rotationally contacts the planar workpiece during rotation of the fastening element.

13. The fastening element according to claim 12, wherein the through-bore has an internal thread.

14. The fastening element according to claim 12, wherein the shaft portion includes a free end portion opposite the nut head and at least one cutting element on the free end portion of the shaft portion.

15. The fastening element according to claim 12, wherein the shaft portion is a hollow cylinder including an end edge in the shape of a ring or a ring segment opposite the nut head.

16. The fastening element according to claim 15, wherein multiple cutting elements are at least locally on the end edge.

17. The fastening element according to claim 16, wherein the multiple cutting elements are in the form of a saw tooth on the cutting device.

Description

DRAWINGS

(1) In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

(2) FIG. 1 shows a schematic sectional view of a fastening element according to the teachings of the present disclosure,

(3) FIG. 2 shows a schematic plan view of a nut head of the fastening element according to FIG. 1,

(4) FIG. 3 shows a sectional view of the fastening element according to FIG. 1 in a first process step of a friction welding procedure according to the teachings of the present disclosure,

(5) FIG. 4 shows a sectional view of the fastening element according to FIG. 1 in a second process step of the friction welding procedure according to the teachings of the present disclosure, and

(6) FIG. 5 shows a sectional view of the fastening element according to FIG. 1 in a third process step of the friction welding procedure according to the teachings of the present disclosure.

(7) The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

(8) The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

(9) FIG. 1 shows a schematic sectional view of a fastening element 1 according to the present disclosure. FIG. 2 shows a plan view of the fastening element 1 according to FIG. 1. A fastening element 1 of this kind may also be referred to as a friction welding nut. This fastening element 1, or this friction welding nut, can be welded onto a workpiece 2 by means of a friction welding procedure, as illustrated in FIGS. 3 to 5.

(10) In the friction welding procedure, the fastening element 1 is pressed against the workpiece 2 and rotated. The resulting friction heat causes the fastening element 1 and/or the workpiece 2 to melt, at least in the region of the contact faces, so that, after the end of the rotary movement and the subsequent cooling and solidification of the melts of both components, a welded connection is established.

(11) The welded-on fastening element 1 provides a possibility for fastening further components to the workpiece 2, which are for example screwed to the workpiece 2 by means of a screw connection with the fastening element. For example, this can be desired in the case of thin-walled sheet-metal parts since the small wall thickness of such parts makes it difficult or impossible to introduce threaded bores.

(12) The fastening element 1 has a nut head 3 and a cutting device 4. An outer contour of the nut head 3 has a key face, for example a hexagonal nut, as shown in the plan view according to FIG. 2. The nut head 3 can be of any size or have any key width. Equally, the outer contour of the nut head 3 can be designed as a square nut or any other known nut shape, or equally may have a cylindrical outer contour.

(13) The nut head 3 has a through-bore 5 which extends along a longitudinal central axis 6 (FIG. 1) of the fastening element 1. The through-bore 5 has an internal thread 7 so that a screw can be screwed into the through-bore 5. The internal thread 7 can be provided either partially or completely along the length of the through-bore 5. In some variations, the internal thread 7 is formed in the through-bore 5 in the region of the nut head 3.

(14) The cutting device 4 is provided on an end side 8 of the nut head 3. A friction welding face 9 is formed on this end side 8. This friction welding face 9 serves to establish the friction-welded connection between the fastening element 1 and the workpiece 2. The friction welding face 9 can be formed either directly by the end side 8 of the nut head 3, or it is possible for a welding component 10, which forms the friction welding face 9, to be provided on the end side 8. The welding component 10 can for example be arranged in the form of a welding ring or annular ring on the end side 8. Providing the welding component 10 makes it possible to use different materials for the nut head 3 and the friction welding face 9. The friction welding face 9 can be designed in the form of a circular ring or a segment on the end side 8, and surrounds the cutting device 4.

(15) The cutting device 4 provided on the end side 8 of the nut head 3 is designed as a cylindrical cutting shaft 11. This cutting shaft 11 extends along the longitudinal central axis 6 from the nut head 3, and has a free end portion 12 at the opposite end from the nut head 3. Multiple cutting elements 13 are arranged at the end portion 12 of the cutting shaft 11. In at least one variation the lateral face of the cutting shaft 11 has a smooth surface. The fastening element 1, or at least the cutting shaft 11, can furthermore be provided with a coating, for example a coating for corrosion protection.

(16) As illustrated in FIG. 1, the cutting shaft 11 is designed as a hollow cylinder. Thus, in some variations the through-bore 5 extends through both the nut head 3 and the hollow-cylindrical cutting shaft 11. In at least one variation the hollow-cylindrical cutting shaft 11 has an internal diameter which corresponds to the internal diameter of the through-bore 5 in the nut head 3. In such a variation the external diameter of the hollow-cylindrical cutting shaft 11 is designed to be smaller than the diameter or key width of the nut head 3.

(17) An end edge 14 is formed on the end portion 12 of the hollow-cylindrical cutting shaft 11. The cutting elements 13 are created or formed on the end edge 14. The cutting elements 13 are arranged along the end edge 14 in the form of a ring or a ring segment, and in some variations designed in the shape of saw teeth. Alternatively, the cutting elements 13 can be designed as cutting segments and provided at a distance from one another on the end edge 14.

(18) By virtue of this configuration, the hollow-cylindrical cutting shaft 11 forms a hole saw, core drill or drill crown. This creates a self-cutting fastening element 1 or a self-cutting friction welding nut. This self-cutting fastening element 1 makes it possible to introduce a drilled hole 15 into the workpiece 2 (i.e., to drill the hole 15 into the workpiece 2) and to friction weld the fastening element 1 to the workpiece 2 in one process step.

(19) The process steps of this combined drilling and friction welding procedure, with the fastening element 1, are illustrated in FIGS. 3 to 5. The fastening element 1 is accommodated by a tool 16 and is placed, with the end edge 14 and the cutting elements 13 provided thereon, against a surface 17 of the workpiece 2, as illustrated schematically in FIG. 3. The tool 16 can be a motor-driven rotary device.

(20) The tool 16 imparts, to the fastening element 1, a rotational movement R about the longitudinal central axis 6, and presses the fastening element 1 against the surface 17 with a force F oriented toward the workpiece 2. Owing to the rotational movement R of the fastening element 1, the cutting elements 13 provided on the end edge 14 execute a rotating cutting motion by means of which the drilled hole 15 is introduced into the workpiece 2.

(21) Once the drilled hole 15 has been introduced into the workpiece 2, the force F moves the fastening element 1 further in the direction of the workpiece 2 until the friction welding face 9 of the end side 8 bears against the surface 17 of the workpiece 2 and a contact face is formed. This is shown in FIG. 4.

(22) Owing to the rotational movement R of the fastening element 1 and the resulting friction heat, the friction welding face 9, or the welding component 10, and/or the surface 17 of the workpiece 2 are/is melted in the region of the contact face. After ending of the rotational movement R and the subsequent cooling and solidification of the melt of the friction welding face 9, or of the welding component 10, and/or of the workpiece 2, a strong friction-welded connection 18 is established between the fastening element 1 and the workpiece 2.

(23) Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

(24) As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

(25) The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.