Title:
BORING METHOD FOR FORMING TAPERING THROUGH HOLE IN WORK BY USING PRESS, AND BORING TOOL THEREFOR
Document Type and Number:
WIPO Patent Application WO/1996/009904
Kind Code:
A1
Abstract:
This invention provides a machining method capable of molding a tapering through hole at a stroke by one pressing operation. The boring of a work is done by using a smaller-diameter punching portion (1a) formed at a front end of a punch (1) fixed to a press. A hole (11) thus made by press molding has an opened lower end with a broken-out section. A tapering surface is formed on the inner side of the hole (11) by plastic machining by a tapering machining portion (1b), which has a diameter somewhat larger than that of the hole and a tapering surface (T), with this hole (11) used as a guide. Due to this plastic machining operation, a burn portion (3a) is going to be formed at an outer circumferential edge portion of the hole (11) but the actual formation of such a portion (3a) is prevented by a holding portion (1c) formed on the punch (1). If these steps are carried out by a single pressing operation, a through hole having a plurality of tapering sectional shapes can be molded more simply.
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Inventors:
TAKEUCHI HIROSATO (JP)
YASUDA SHIGERU (JP)
KUBO HARUO (JP)
YASUDA SHIGERU (JP)
KUBO HARUO (JP)
Application Number:
PCT/JP1995/001949
Publication Date:
April 04, 1996
Filing Date:
September 27, 1995
Export Citation:
Assignee:
NITTO KOHKI CO (JP)
TAKEUCHI HIROSATO (JP)
YASUDA SHIGERU (JP)
KUBO HARUO (JP)
TAKEUCHI HIROSATO (JP)
YASUDA SHIGERU (JP)
KUBO HARUO (JP)
International Classes:
B21C37/28; B21C37/29; F16L21/00; B21D28/16; B21D28/24; B21D28/34; B21K1/00; (IPC1-7): B21D28/24
Foreign References:
| JPS5677028A | 1981-06-25 | |||
| JPS6395623U | 1988-06-20 | |||
| JPS532437U | 1978-01-11 | |||
| JPS59174233A | 1984-10-02 |
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