Friction joining element
AssigneeJfe Steel Corporation
InventorsNaoaki Munemura, Hiroshi Matsuda, Yoshiaki Murakami
Life of this patent
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Abstract
A friction joining element for mechanically joining a sheet set prepared by stacking two or more metal sheets including a high strength steel sheet as an upper sheet. The friction joining element includes a mandrel having an overall length adjusted to be equal to or less than the total thickness of the sheet set, and a collar disposed at an upper portion of the mandrel. The friction joining element has a screw thread on a side surface of a head-side portion of the mandrel.
Claims2
A friction joining element for mechanically joining a sheet set prepared by stacking two or more metal sheets including a high strength steel sheet as an upper sheet, the friction joining element comprising:
- a mandrel having an overall length adjusted to be equal to or less than a total thickness of the sheet set;
- a collar disposed at an upper portion of the mandrel, the collar having an umbrella shape;
- and
- a screw thread disposed on a side surface of a head-side portion of the mandrel, wherein:
- the screw thread includes a plurality of ridges formed continuously in a length direction of the mandrel,
- a plurality of ridges of the screw thread in a side surface region of the mandrel is from 2 to 20 inclusive,
- a distance between adjacent ridges of the plurality of ridges is in a range of 100 to 500 μm;
- an inclination angle of the screw thread is between 1° and 180°, and
- a forward end portion of the mandrel has a tapered shape protruding forward with an angle of the tapered shape being between 120 and 180°.
Dependencies are inferred from the claim text.