| 摘要 |
PURPOSE:To obtain a small size and simple magnetic detecting sensor with excellent speed response by concentrically forming a plurality of magnetic thin film tracks on one surface of a rotating plate connected to a rotating shaft. CONSTITUTION:A plurality of magnetic thin film tracks 3 with a magnetic pole pitches different from one another are concentrically formed on the surface of a rotating plate 2. A magnetic detecting element 7 wherein a high frequency exciting coil 5 and a detecting coil 6 are lap-wound around amorphous alloy thin wires 4 is perpendicularly and oppositely provided to the tracks 3 so that the distal ends of the thin wires 4 approach the tracks 3. As a result, the surface leakage magnetic field of the magnetic poles of the tracks 3 is taken out from the coil 6 for every track 3 as amplitude- modulated high frequency induced voltage by utilizing the magnetic saturation of the thin wires 4. The amplitude-modulated components of the amplitude-modulated high frequency induced voltage are taken out and converted to binary signals in a position detecting circuit 26. The circumferential direction position of the rotating plate 2 is detected by combining the binary signals from the tracks 3. The rotational angle and rotating speed of the rotating plate 2 are detected by counting the binary signals from the specific track 3.
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