To achieve a manufacturing method capable of reducing weight and costs of a cage.
A first intermediate material 13a shown in (A) is formed by performing punching work on a metallic plate as a raw material first, and then bent portions 24, 24 are intermittently formed on an inner peripheral edge portion to form a spare intermediate material 25 shown in (B). Then a plurality of through holes 14, 14 are formed to form a second intermediate material 16a shown in (C). Then burring work is performed on the second intermediate material 16a to obtain a third intermediate material 19a shown in (C). A width dimension of a part of each of strip portions 17a, 17a can be prevented from being excessively reduced in burring work on the basis of the existence of each of bent portions 24, 24.
NAKAMURA TOSHIO
WADA YOSHIHIKO
| JP2001038440A | 2001-02-13 | |||
| JP2005090740A | 2005-04-07 | |||
| JP2004293730A | 2004-10-21 |
Nakai Shun
Kinzo Koyama