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Patent Searching and Data


Title:
HOLE-WIDENING MACHINING METHOD, MOLDING TOOL, MOLDING AND MACHINING METHOD
Document Type and Number:
WIPO Patent Application WO/2017/038976
Kind Code:
A1
Abstract:
This hole-widening machining method has a preparation step for preparing a workpiece formed with a pilot hole and a molding tool having a widening diameter part having a wider diameter from a tip end side toward a rear end side and a linear protrusion formed to protrude from the surface of the widening diameter part to the outside, and a hole widening step for gradually widening the pilot hole in the workpiece by pressing the molding tool into the pilot hole so that the linear protrusion of the molding tool touches a portion of the circumferential edge of the pilot hole at least twice to form a stretch flange.

Inventors:
NITTA JUN (JP)
YONEMURA SHIGERU (JP)
SHIRAKAMI SATOSHI (JP)
YASUTOMI TAKASHI (JP)
Application Number:
PCT/JP2016/075802
Publication Date:
March 09, 2017
Filing Date:
September 02, 2016
Export Citation:
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Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
B21D19/08
Foreign References:
JP2001239325A2001-09-04
JP2001212625A2001-08-07
JPH0739948A1995-02-10
JP2000326018A2000-11-28
US6931901B22005-08-23
JPH0739945A1995-02-10
JPH0739946A1995-02-10
Other References:
See also references of EP 3345690A4
Attorney, Agent or Firm:
SHIGA Masatake et al. (JP)
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