Compression coil spring and manufacturing device and manufacturing method for coil spring

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 8695956
APP PUB NO 20120013059A1
SERIAL NO

13244529

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Abstract

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Bending deformation exceeding a yield stress is applied by winding a material on a mandrel. Coiling is performed simultaneously with the application of the bending deformation, and the load is removed after the coiling. This spring includes an outside surface region having a compressive residual stress and a compressive stress reduction region in which the compressive residual stress is reduced from the outside surface region toward the center of the material. A stress change portion at which a change from the compressive residual stress to a tensile residual stress occurs exists between the outside surface region and the center of the material. The spring further includes a tensile stress peak portion, tensile stress reduction region, and inside surface region. The inside surface region has the tensile compressive residual stress having an absolute value smaller than that of the outside surface region.

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Patent Owner(s)

Patent OwnerAddress
NHK SPRING CO LTDKANAGAWA KANAGAWA

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Hamano, Toshio Yokohama, JP 32 769
Okada, Hideki Yokohama, JP 148 614
Yamamotoya, Kenji Yokohama, JP 6 29

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