Title:
METHOD FOR MANUFACTURING DOOR HINGE FOR AUTOMOBILE
Document Type and Number:
WIPO Patent Application WO/2012/081454
Kind Code:
A1
Abstract:
The present invention enables a high strength door hinge for an automobile to be manufactured at low cost from a steel round bar by hot forging, punching, etc.
A method for manufacturing a door hinge for an automobile manufactures the door hinge by forming, by hot forging a steel round bar, a forged product (33a) provided with a mounting section, an arm section, and a column-shaped section (7a) which has a circular horizontal cross-section, and by forming a shaft hole (6), in which a hinge pin is inserted so as to penetrate through the axis of the column-shaped section (7a), in the column-shaped section (7a) by means of punching using a specialized die (52a) and a punch (51). The die (52a) is provided with a gap which is formed so that, in forming the shaft hole (6), when the punch (51) is moved from the start position of punching by a predetermined distance, the punch (51) forms a hole while causing the column-shaped section (7a) to swell outward without producing punch debris, and when the punch (51) is moved to the end position of punching from the position at the predetermined distance from the start position of punching, the punch (51) forms a hole while producing punch debris which is discharged through the gap. The method enables the shaft hole (6) to have a height which is two or more times as large as the diameter of the punched hole, and as a result, the door hinge for an automobile has sufficient strength and can be manufactured at low cost.
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Inventors:
OGAWA HIROSHI (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
Application Number:
PCT/JP2011/078240
Publication Date:
June 21, 2012
Filing Date:
December 07, 2011
Export Citation:
Assignee:
OGAWA HIROSHI (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
OGAWA KAZUYA (JP)
YOKOYAMA MICHIHIRO (JP)
International Classes:
B21K13/02; B21D53/40; B21D53/88; B21J5/02; B21J5/10; B21J13/02
Domestic Patent References:
| WO2006126622A1 | 2006-11-30 |
Foreign References:
| JPS57127541A | 1982-08-07 | |||
| JPH10205200A | 1998-08-04 | |||
| JPH0544765U | 1993-06-15 | |||
| 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: