Title:
METHOD OF MANUFACTURING DOOR HINGE FOR AUTOMOBILE
Document Type and Number:
WIPO Patent Application WO/2011/118378
Kind Code:
A1
Abstract:
Disclosed is a method of manufacturing a high-strength door hinge for an automobile from a tabular steel material at low cost, which comprises a pressing step in which a cylindrical bulging portion is formed at an end of the material in the breadth direction; a shaft-hole boring step in which a shaft hole is bored in the cylindrical bulging portion; and a shaft-hole finishing step. In the shaft-hole boring step, a shaft hole is bored using a first punch having a conical end and a first die having a clearance volume between the outer circumference of the cylindrical bulging portion and the inner wall of the die. The clearance volume has a size such that, during punching of the cylindrical bulging portion using the first punch, no punching debris is produced and the cylindrical bulging portion bulges outward at a hole portion to be formed between an end at which machining starts and a predetermined position and such that punching debris is produced and discharged from a hole portion to be formed when the first punch is located between the predetermined position and an end at which machining ends. In the shaft-hole finishing step, the shaft hole is finished from the end at which machining ends using a second die having substantially the same shape as the first die and a second punch having a conical or truncated conical end and a maximum diameter larger than that of the first punch.
Inventors:
OGAWA HIROSHI (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
Application Number:
PCT/JP2011/055321
Publication Date:
September 29, 2011
Filing Date:
March 08, 2011
Export Citation:
Assignee:
OGAWA HIROSHI (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
International Classes:
B21K1/76; B21D28/34; B21D53/40; B21J5/08; B21J5/10; B21J13/02; B21K13/02; B60J5/04
Foreign References:
| JPS56117850A | 1981-09-16 | |||
| JP2005238326A | 2005-09-08 | |||
| JP2005205498A | 2005-08-04 | |||
| JP2006068836A | 2006-03-16 | |||
| JP2006170331A | 2006-06-29 | |||
| JPH06240943A | 1994-08-30 | |||
| JPS50137354A | 1975-10-31 | |||
| JP2006214259A | 2006-08-17 | |||
| JPH08197952A | 1996-08-06 | |||
| JP2008223247A | 2008-09-25 |
Attorney, Agent or Firm:
SUGIMOTO KATSUNORI (JP)
Katsunori Sugimoto (JP)
Katsunori Sugimoto (JP)
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Claims:
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