| 摘要 |
PURPOSE:To provide a magnetic detector for working amount which eliminates the necessity of a power source, improves a detecting precision, and is manufactured at a low cost, by a method wherein a magnetic code plate is located away from a pair of arm parts of a yoke member, whereto a permanent magnet is attached, with a space gap arranged therebetween, an inductive voltage is produced at an inducing coil because of a change in a gap as a result of movement of the code plate, and the voltage is processed to detect a working amount. CONSTITUTION:A code plate made of a magnetic material is pivotably supported by a center axis 1a, and projections 2a, 2b, 3a, and 3b, formed on forward ends of a pair of arm parts 2e and 3e of yoke members 2 and 3 made of the magnetic material, are located in a number of concavities and convexities 1c and 1b, formed in the outer periphery of the code plate 1, so that they are positioned facing and opposite to the parts 1a and 1b with a gap between. If the code plate 1 turns, a magnetic flux changes, and an induction voltage, corresponding to the change rate of the magnetic flux, is generated at an inducing coil 5. Additionally, a peripheral length of the one full convexity 1b is shorter than that of one full concavity 1c, whereby a rapid change in magnetic flux density occurs and an output wave is brought into a sharp peak. |
