シェービングねじ成形接合法による薄板重ね継手の形成

抄録

Shave joining with a screw was experimentally confirmed as very promising for forming a single lap joint between sheets such as mild steel, aluminum, plastics, and fiber-reinforced plastics. Here, an external screw of hard steel serves as a rivet, but its threads shave a machined bore of lapped sheets into an internal screw. The press insertion force is much smaller than that of riveting, resulting in a decrease in working noise. The joint surface can be flat when using a flat-headed screw. Although the engagement between screw and bore is tight through lapped sheets, its joint can essentially be disassembled, when required. The strength of the lap joint under tensile stress is markedly improved as the screw pitch decreases or screw number increases. Furthermore, the value becomes maximum using a headed screw, thereby upsetting the stem bottom. Such effects are successfully caused by control of specimen curling or screw pullout in testing. The screw should be harder than sheets to be joined. Softening of plastics and its composites by a heated screw is utilized to fasten the screw and bore wall closely.