Manufacture of coil core for stepper motor e.g. for internal combustion engine flow control valve, by fitting yokes into positioning device in molding die and injecting resin

摘要

A molding die (40) is provided with a positioning device (50) for holding multiple yokes in a predetermined position. With the die open, the yokes are consecutively fitted into the positioning device to form a stack. The die is then closed, and a melted synthetic resin is injected into the die, to form a coil core (20) of synthetic resin, containing the yokes. Independent claims are included for a molding die, and for a yoke set.