Title:
METAL FITTING, ROLLING DIE, AND METHOD FOR FORMING MALE THREAD
Document Type and Number:
WIPO Patent Application WO/2018/097043
Kind Code:
A1
Abstract:
Through the present invention, a male thread is appropriately formed. A thread part provided to a cylindrical metal fitting according to the present invention includes a first thread formation portion and a second thread formation portion. The thickness of the second thread formation portion in a groove bottom thereof is greater than the thickness of the first thread formation portion in a groove bottom thereof. The thread height in the first thread formation portion is less than the thread height in the second thread formation portion. A roll forming die according to the present invention has a roll forming part including a groove part and a crest part. The groove depth in a first thread roll-forming portion of the roll forming part for forming a male thread in a first metal fitting portion where a metal fitting is thin is less than the groove depth in a second thread roll-forming portion in the roll forming part for forming a male thread in a second metal fitting portion where the metal fitting is thick. The metal fitting is caused to roll in relative fashion along the roll forming part in a state in which the roll forming die such as described above is pressed against the metal fitting, and a male thread is thereby formed in the metal fitting.
Inventors:
HASEGAWA NORIYASU (JP)
Application Number:
PCT/JP2017/041386
Publication Date:
May 31, 2018
Filing Date:
November 17, 2017
Export Citation:
Assignee:
NGK SPARK PLUG CO (JP)
International Classes:
B21H3/04; F16B35/00
Foreign References:
| JP2005511319A | 2005-04-28 | |||
| JP2001349313A | 2001-12-21 | |||
| JP2016167429A | 2016-09-15 | |||
| JP2016078094A | 2016-05-16 |
Attorney, Agent or Firm:
NAKAJIMA Hiroki et al. (JP)
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