Title:
METHOD FOR EXTRUSION-MOLDING DIFFERENTIAL-THICKNESS PIPE, AND DEVICE FOR EXTRUSION-MOLDING DIFFERENTIAL-THICKNESS PIPE
Document Type and Number:
WIPO Patent Application WO/2021/044689
Kind Code:
A1
Abstract:
Through the present invention, in extrusion processing in which diameter reduction is performed by pressing a pipe stock having a core metal inserted therein into a die having a small-inside-diameter part on the distal-end side thereof, a differential-thickness pipe having a thick-walled part at the distal end thereof can easily be molded by using a core metal in which a small-cross-section part is formed at the distal end thereof. Specifically, a differential-thickness pipe can be manufactured with high production efficiency and at low cost. By using a pipe stock in which a thin-walled part is formed at the distal end thereof, it is also possible to mold a differential-thickness pipe having a thick-walled part at a position midway along the axial direction thereof. This pipe stock in which a thin-walled part is formed at the distal end thereof can be molded through an extrusion step in which there is used a core metal that does not comprise a small-cross-section part at the distal end thereof, prior to the step for forming the thick-walled part as described above, for example. Furthermore, when higher dimensional precision is required, a so-called "counterpunch" may be used in the step for forming the thick-walled part.
More Like This:
| JPS60174804 | PRODUCTION OF PIPE |
Inventors:
NOZU KENTARO (JP)
NAKAGAKI MICHIHARU (JP)
NAKAGAKI MICHIHARU (JP)
Application Number:
PCT/JP2020/022822
Publication Date:
March 11, 2021
Filing Date:
June 10, 2020
Export Citation:
Assignee:
SANGO CO LTD (JP)
International Classes:
B21C23/08; B21C25/08
Domestic Patent References:
| WO2017154481A1 | 2017-09-14 |
Foreign References:
| JPS56168902A | 1981-12-25 | |||
| JP2016068088A | 2016-05-09 | |||
| JPS61135419A | 1986-06-23 | |||
| JPS5973115A | 1984-04-25 |
Attorney, Agent or Firm:
PROSPEC PATENT FIRM (JP)
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