摘要 |
A low cost, high tolerance molded coil is disclosed together with a method of constructing the same. A wound coil is provided with connection leads. A mold having a mold cavity therein for the formation of an integral outer core and for supporting the coil is provided. The mold also produces integral securing portions for securing the coil to the outer core. The wound coil is placed in the mold cavity and a pre-molded and pre-shrunk plastic inner core is positioned inside of the coil substantially along the coil's longitudinal center line. A heated molding plastic is injected into the mold cavity so as to form the integral outer core for supporting the coil and securing portions of the coil. The molded coil is cooled and removed from the mold without withdrawing the inner core from the molded coil, which thereafter remains in the finished product. By use of the pre-molded and pre-shrunk plastic inner core, shrinkage and other deformations of the outer core is prevented. Consequently, the coil inductance is maintained at a high tolerance.
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