| 摘要 |
PROBLEM TO BE SOLVED: To provide a proximity sensor capable of preventing reduction in detection sensitivity even if a thick surface is to be detected and the sensor is placed by being embedded in a mounting metal member formed of a magnetic metal, such as iron or the like. SOLUTION: The magnetic flux FL1 from a detection coil 6 to a side part 24 is induced in the direction toward the mounting metal member, so that a part of the magnetic flux FL1 reaches the mounting metal member as the magnetic flux FL3. Eddy current is generated by the magnetic flux FL1 in the side part 24; the magnetic flux FL2 is generated in the direction toward a detection coil 6 by the eddy current, and the magnetic flux FL4 is generated toward the mounting metal member 51. The magnetic fluxes FL2 and FL4 cause loss due to the eddy current in the mounting metal member 51. Since the magnetic flux passes easily in the side part 24, the loss due to the eddy current decreases in the side part 24, but it increases in the mounting metal member 51. By adjusting oscillation frequencyω, the loss due to the leak magnetic flux is adjusted so that it does not change irrespective of existence of the mounting metal member 51. COPYRIGHT: (C)2007,JPO&INPIT
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