| 摘要 |
PROBLEM TO BE SOLVED: To facilitate the smooth rotation and the adjusting operation of a ferrite core, and to prevent breakage, by a method wherein the ferrite core has a fluororesin film and the fluororesin film is formed by tetrafluoro-echylene. SOLUTION: Tetrafluoro-echylene powder is uniformly adhered to the screw part 4 of a ferrite core 1. At this point, when the tetrafluoro-echylene powder is uniformly adhered to the screw part 4 of the ferrite core 1, the ferrite core 1 is put in a heating oven and it is retained at 330 to 395 deg.C for at least 20 minutes. Besides, the weight of the part to be coated should be 1.0 to 3.0 wt.% against the weight of the ferrite core 1, and the film thickness of the screw part 4 should be 15 to 45 μm Also, the rotary torque of the ferrite core 1, where tetrafluoro-echylene films 2a and 2b are formed, should be 20 to 50 gf cm. |
