SCREW FASTENING STRUCTURE WITH HIGH-STRENGTH SELF-FORMING SCREW

Title:

SCREW FASTENING STRUCTURE WITH HIGH-STRENGTH SELF-FORMING SCREW

Document Type and Number:

WIPO Patent Application WO/2010/007649

Kind Code:

A1

Abstract:

To provide a screw fastening structure for enhancing the strength of a bolt and fatigue strength by reducing the machining process without altering the shape of an associated member, and for achieving downsizing by keeping the fitting length of a thread almost the same as that of the prior art, thus contributing remarkably to weight reduction of a vehicle. A self-forming screw (1) having a strength 14T produced by form rolling before heat treatment is employed as a fastening bolt, and the self-forming screw is driven into a member (4) having an as-cast, nonthreaded rough hole (5). In a screw fastening structure to which a fixing member (6) is fastened, the catch rate of a female screw and a male screw formed by a self-form is 75-90%, the fitting length of the screw and the rough hole is d-2.5d (d is screw diameter), and no clearance appears at the contact surface of the male and female screws because of self-forming screw fastening.

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Inventors:

MORI SHIGETO (JP)
UMADA AKIHIDE (JP)
MATSUNO MAYUMI (JP)

Application Number:

PCT/JP2008/003641

Publication Date:

January 21, 2010

Filing Date:

December 08, 2008

Export Citation:

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Assignee:

TOPURA KK (JP)
MORI SHIGETO (JP)
UMADA AKIHIDE (JP)
MATSUNO MAYUMI (JP)

International Classes:

F16B5/02; F16B25/06

Foreign References:

JP2001289221A	2001-10-19
JP2008014344A	2008-01-24
JPS6452045A	1989-02-28
JP2008095793A	2008-04-24
JPH081340U	1996-09-03

Other References: