Title:
SCREW AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2018/158845
Kind Code:
A1
Abstract:
[Problem]
To provide a screw that can be screwed in until the screw closely adheres to the surface of a workpiece.
[Solution]
A screw wherein a complete male screw section 21 forming a helical complete male thread crest shape and an incomplete male screw section 22 forming an incomplete male thread crest shape continuous with the complete male screw section 21 are formed by carrying out rolling on a raw material leg part 6 the diameter of which has been set so as to be substantially the same as the effective diameter ⌀A of the male screw. The raw material leg part 6 is integrally provided with an effective diameter shaft section 6c the effective diameter of which is set to ⌀A, and an annular groove 6b having a smaller diameter than the effective diameter shaft section 6c. The annular groove 6b has a diameter that is smaller than the effective diameter ⌀A and larger than the valley diameter ⌀H of the complete male screw section 21. The raw material leg part 6 is elastically deformed by rolling to form a screw leg part 20 wherein a screw portion 20c comprising the complete male screw section 21 and the incomplete male screw section 22, and an annular groove portion 20b having a shorter axial length than the annular groove 6b are formed. The incomplete male screw section 22 forms an incomplete male thread crest shape that is gradually reduced in the diameter direction from the effective diameter shaft section 6c toward the annular groove 6b of the raw material leg part 6.
Inventors:
OMORI YUUSAKU (JP)
YOKOTA MASANORI (JP)
YOKOTA MASANORI (JP)
Application Number:
PCT/JP2017/007939
Publication Date:
September 07, 2018
Filing Date:
February 28, 2017
Export Citation:
Assignee:
NITTO SEIKO KK (JP)
International Classes:
F16B33/02; B21H3/02
Foreign References:
| JPS56146115U | 1981-11-04 | |||
| JP2003247522A | 2003-09-05 | |||
| JP2002020839A | 2002-01-23 | |||
| JPH07310723A | 1995-11-28 | |||
| JPH02268935A | 1990-11-02 | |||
| JPS56141932A | 1981-11-05 |
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