| 摘要 |
PURPOSE:To attain the miniaturization and wt. reduction of the titled detection apparatus while enhancing detection accuracy, by forming a magnetic closed loop and providing a magnetic sensor in said loop while arranging a magnet and the magnetic sensor at a position where magnetic flux is largely changed. CONSTITUTION:A sensor part 12 constituted of a non-magnetic material comprising an epoxy resin is provided at a position where a metal sphere passing a pass route 11 constituted of a non-magnetic substance must be detected. The sensor part 12 has a frame formed so as to surround the route 11 and a noise removing shield plate 13 is provided in the frame. On the other hand, a magnetic path 16 comprising a ferromagnetic body has a right angle bent part and a permanent magnet 14 and a hole element 15 are arranged at an angle of 90 deg.C with respect to the center point of the route 11. When the metal sphere passing the route 11 reaches a position piercing the permanent magnet 14 and the hole element 15, magnetic flux density piercing the hole element reaches a max. value. The value at this time is detected by the sensor part 12 and the signal thereof is amplified by an amplifier 22 and easily separated by a Schmidt trigger circuit 23 to make it possible to certainly detect the metal sphere. |
