| 摘要 |
The present invention provides a coil bobbin manufactured by injection molding a thermoplastic resin with a mold having a cavity of a predetermined shape corresponding to the coil bobbin. The coil bobbin includes a tubular main body consisting of a tubular wall having an upper end and a lower end, an upper flange being formed to surround the upper end of the tubular wall and having a thinner wall portion and a thicker wall portion, a lower flange being formed to surround the lower end of the tubular wall and having an upper face and a bottom face, and a pair of feet protruded downward from the bottom face of the lower flange. The thinner wall portion has a thickness of not greater than a predetermined thickness of the tubular main body, and the thicker wall portion has a thickness of not less than the predetermined thickness. The predetermined thickness is not greater than 0.5 millimeter, and more specifically not greater than 0.2 millimeter. This structure of the invention makes the thin tubular wall free from undesirable weld marks or air pockets and allows a longer lead wire to be wound on the tubular wall to enhance the response of the electromagnetic coil.
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