| 摘要 |
PURPOSE: To detect the whole motion range of a piston by providing a sensor in a cylinder cover to estimate with an electric estimation device provided corresponding to the sensor. CONSTITUTION: An operation cylinder 10 is provided on both sides with a non- magnetic material made cylinder pipe 13 closed by cylinder covers 11, 12. Also, the cover 11 is provided in a notch with a sensor 20 and switch 21. This sensor 20 consists of an electrified coil and an alternating field is generated through an end face facing to a piston 14 to produce eddy current on a metallic plate 15. The energy loss reduces impedance in the sensor 20 and a load on the coil is successively increased with the reduction of a gap between the sensor 20 and metallic plate 15. Thus, the whole motion range of the piston 14 can be detected by the use of a graph representing the relationship between the gap between the piston 14 and sensor 20 and the output voltage of the sensor 20. |
