| 摘要 |
PROBLEM TO BE SOLVED: To provide a coil with core which provided less amount of eddy current loss caused by a leakage magnetic flux from a gap. SOLUTION: A polyester film 6 is inserted between end portions of semi- annular ferrite pieces 4a, 4b to form a gap 5 between end portions. Under this condition, the surfaces of ferrite pieces 4a, 4b and coated with a coating resin 6. A coil 3 is formed by coiling a copper wire including insulating coating is around a core 2 for the predetermined number of turns. In this case, at the position corresponding to the gap 5 in the coil 3, density of copper wire becomes rougher than the other portions of coil 3. Since the number of copper wires through which the leakage magnetic flux is generated at the area near the gap 5 is rather small, eddy current loss generated by the leakage magnetic flux of copper wire is also reduced. |
