Title:
MANUFACTURE OF CYLINDRICAL MEMBER FOR VEHICLE BODY STRUCTURE
Document Type and Number:
Japanese Patent JP3748093
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a rectangular section in which no shrinkage causing locally reduced wall thickness is generated in the case of bulging and forming a cylindrical member for vehicle body structure having a closed section of approximately rectangular shape.
SOLUTION: In a manufacturing method of a cylindrical member for vehicle body structure in which a cylindrical member 20 of closed section with its wall thickness changed in the peripheral direction is formed, and the bulging is effected by applying the pressure inside the cylindrical member at least in a condition that the cylindrical member is held in a bulging die to demarcate the outer contour of the final sectional shape of approximately rectangular shape, and the initial sectional shape 20' before the bulging is formed into the final sectional shape of approximately rectangular shape, the bulging is effected in a condition that areas in the vicinity of side wall contact points P1, P2 first in contact with a side wall of the bulging die are formed into a thick walled part 21c having gradually thinner wall thickness as the initial sectional shape 20' before the bulging goes close to a longitudinal wall equivalent part 21 to become a longitudinal wall of the final sectional shape from a lateral wall equivalent part 22 to become a lateral wall of the final sectional shape.
Inventors:
Nakagawa Shigeyuki
Kenji Kanamori
Kenji Kanamori
Application Number:
JP14333898A
Publication Date:
February 22, 2006
Filing Date:
May 25, 1998
Export Citation:
Assignee:
Nissan Motor Co., Ltd
International Classes:
B21D7/00; B21D26/033; B21D26/041; B21D53/86; B21D53/88; (IPC1-7): B21D26/02; B21D7/00; B21D53/86
Domestic Patent References:
| JP8168814A | ||||
| JP61273222A |
Attorney, Agent or Firm:
Janggi Motonori