Methods of manufacturing rotor core for motor-driven valve, rotor feed screw and rotor

摘要

To improve methods of manufacturing a rotor core, a rotor feed screw, and a rotor for motor-driven valves and reduce manufacturing cost of the motor-driven valves. A method of manufacturing the rotor core comprising the steps of: using an openable/closable die device 23 defining a molding recess 28 for the sleeve 14; forming to the die device 23 a molding recess 24a for the valve closing limit stopper 14a and a first positioning portion 27a positionally corresponding to the molding recess 24a; forming to the bushing 11 a second positioning portion 11c such that when the second positioning portion 11c coincides with the first positioning portion 27a a thread-cut leading end 11b of the female screw 11a and the molding recess 24a for the valve closing limit stopper 14a are positionally corresponding to each other; mounting the bushing 11 to the die device 23 such that the second positioning portion 11c coincides with the first positioning portion 27a; and closing the die device 23 and casting molten resin into the molding recess 28 to manufacture the rotor core 19. In the same manner as described above, a rotor feed screw 20 and a rotor 40 can be manufactured.