To mold respective side pieces of a polygonal cylinder part of a yoke, including the polygonal cylinder part and an oval cylinder part, with good plane precision.
A yoke 4 is molded through the processes of: molding a base material 10 into a first intermediate body 11 in a bottomed cylinder shape; molding the first intermediate body 11 into a third intermediate body 13 having a hexagonal cylinder part 13b, an inclined cylinder part 13c, and a cylinder part 13d on the side of a bottom part 13a; and molding a fourth intermediate body 14 having a flat part corresponding part 14F which is long in a shaft core direction including the inclined cylinder part 13c and cylinder part 13d of the third intermediate body 13 as a flat plate corresponding part 14d. The flat part corresponding part 14F of the fourth intermediate body 14 to become a flat part F of the yoke 4 is molded using a die 15 having a projection piece 15h as a deformation stop part stopping an inner surface of the flat part corresponding part 14F from deforming on molding surfaces 15b, 15c opposed to the flat part corresponding part 14F.
TORISHIMA HIDEO
HORIUCHI HIDEKI
MICHIZAKI ATSUSHI
IMAMURA YUSUKE
| JP2010263689A | 2010-11-18 | |||
| JP2002160021A | 2002-06-04 | |||
| JP2003326323A | 2003-11-18 |
Suzuki Yuko