Friction bit joining of materials using a friction rivet

Patent metadata

Field	Value
Publication number	US-9764375-B2
Application number	US-201414153814-A
Country	US
Kind code	B2
Filing date	Jan 13, 2014
Priority date	Mar 2, 2012
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A system and method of joining at least two workpieces together using a friction rivet and a friction rivet cap that are friction stirred together after a cutting tip or cutting feature on the friction rivet cuts through workpieces and is then bonded to the friction rivet cap, and wherein the friction rivet cap may be excluded if the friction rivet includes a hollow in the cutting tip, the hollow being flared after the friction rivets cuts through the workpieces to thereby create an integral rivet cap in the end of the friction rivet.

First claim

What is claimed is:

1. A joint system for joining at least two workpieces using a friction rivet, said joint system comprised of:
a first workpiece and a second workpiece, the first workpiece including a first metallic material and the second workpiece including a second metallic material, wherein the first workpiece is adjacent to and contacting the second workpiece;
a friction rivet joining tool having an attaching end and a shoulder, the shoulder configured to at least partially contact the first metallic material, the friction rivet joining tool being configured to rotate the attaching end, the friction rivet joining tool having a variable rotation speed, the variable rotation speed configured to selectively increase or decrease a rotation speed of the attaching end;
a friction rivet that is held by the friction rivet joining tool at the attaching end, wherein the friction rivet includes a cutting tip configured to cut through the first workpiece and the second workpiece, wherein the friction rivet is joined to the first workpiece and the second workpiece at least in part as a result of friction heating and plasticization of at least one of the friction rivet, the first metallic material or the second metallic material, the friction heating and plasticization incurred by applied pressure and rotation of the friction rivet on the first metallic material and the second metallic material; and
a friction rivet cap attached to the friction rivet, the cutting tip passing through the friction rivet cap after passing through the first metallic material and the second metallic material.

2. The joint system as defined in claim 1 wherein the friction rivet has a threaded outer surface.

3. The joint system as defined in claim 1 wherein the joint system is further comprised of a hollow disposed in the cutting tip of the friction rivet.

4. The joint system as defined in claim 3 wherein the joint system is further comprised of a flaring tool for flaring the friction rivet at the hollow, to thereby cause an end of the friction rivet to flare outwards to create an integral rivet head, the integral rivet head forming at least in part a mechanical interface used to hold the friction rivet and friction rivet cap in place, the integral rivet head at least partially metallurgically bonded to the friction rivet cap.

5. A joint system for joining at least two workpieces using a friction rivet, said joint system comprised of:
a first workpiece and a second workpiece, the first workpiece including a first metallic material and the second workpiece including a second metallic material;
a friction rivet joining tool having an attaching end and a shoulder, the shoulder configured to at least partially contact the first metallic material, the friction rivet joining tool being configured to rotate the attaching end, the friction rivet joining tool having a variable rotation speed, the variable rotation speed configured to selectively increase or decrease a rotation speed of the attaching end;
a friction rivet including a cutting tip and a hollow disposed in the cutting tip, wherein the cutting tip is configured to cut the first workpiece and the second workpiece by the cutting tip and becomes flared following cutting of the first workpiece and the second workpiece, wherein the friction rivet is joined to the first workpiece and the second workpiece at least in part as a result of friction heating and plasticization of at least one of the friction rivet, the first metallic material or the second metallic material, the friction heating and plasticization incurred by applied pressure and rotation of the friction rivet on the first metallic material and the second metallic material;
a friction rivet cap attached to the friction rivet, the friction rivet passing at least partially through the friction rivet cap; and
an integral rivet head formed by flaring the cutting tip of the friction rivet following cutting of the first metallic workpiece and the second metallic workpiece to hold the friction rivet in place.

6. The joint system as defined in claim 5 wherein the joint system is further comprised of a threaded outer surface on the friction rivet.

7. The joint system as defined in claim 5 wherein the joint system is further comprised of a pre-cut hole disposed through the at least two workpieces.

8. The joint system as defined in claim 2 , wherein the friction rivet cap includes a threaded inner surface.

9. A joint system for joining at least two workpieces using a friction rivet, said joint system comprised of:
a friction rivet including a cutting tip and a hollow disposed in the cutting tip, wherein the cutting tip is configured to cut through a first metallic workpiece and a second metallic workpiece, the hollow longitudinally extending through the cutting tip and at least partway into the friction rivet, the hollow facilitating cutting of the first metallic workpiece and the second metallic workpiece; and
a friction rivet cap configured to receive and join to the friction rivet, the friction rivet cap is configured to contact the second metallic workpiece on an opposite side of the second metallic workpiece from the first metallic workpiece and from a surface of the second metallic workpiece through which the cutting tip of the friction rivet cuts, the friction rivet cap having a pre-cut hole extending therethrough wherein at least a portion of the cutting tip of the friction rivet extends through the friction rivet cap and from the second metallic workpiece when joined to the friction rivet.

10. The joint system as defined in claim 9 , wherein the friction rivet is a portion of a multi-segmented friction rivet.

11. The joint system as defined in claim 9 , wherein an outer surface of the friction rivet has planar sides.

12. The joint system as defined in claim 9 , wherein the friction rivet and friction rivet cap comprise different materials.

13. The joint system as defined in claim 9 , wherein an inner surface of the pre-cut hole is threaded.

14. The joint system as defined in claim 9 , wherein an outer surface of the friction rivet is threaded.

15. The joint system as defined in claim 9 , wherein both an inner surface of the pre-cut hole and an outer surface of the friction rivet are threaded.

16. The joint system as defined in claim 1 , wherein the friction rivet cap includes a pre-cut hole and an inner surface of the pre-cut hole is threaded.

17. The joint system as defined in claim 1 , wherein the friction rivet is part of a plurality of friction rivets, connected together lengthwise to form a multi-segmented bit.

18. The joint system as defined in claim 1 , wherein the friction rivet and friction rivet cap comprises the same material to enable diffusion bonding therebetween.

19. The joint system as defined in claim 1 , wherein at least a portion of the cutting tip is exposed.

Assignees

• Megastir Tech Llc
• Univ Brigham Young

Inventors

• Miles Michael P
• Fleck Rodney Dale
• Steel Russell J

Classifications

• B23K20/1255 Primary

  Tools therefor, e.g. characterised by the shape of the probe · CPC title

• B23K20/1215

  for other purposes than joining, e.g. built-up welding · CPC title

• Y10T29/5377

  Riveter · CPC title

• B23K20/1265

  Non-butt welded joints, e.g. overlap-joints, T-joints or spot welds · CPC title

• B23K20/127

  Friction stir welding involving a mechanical connection · CPC title