| 摘要 |
PURPOSE:To effectively detect a magnetic flux for magnetizing to detect the rotating position or to control the rotating speed of a rotor by providing a shielding member made of a ring-shaped high magnetic permeability material between magnetized parts for detecting the rotating position. CONSTITUTION:A driving magnetized part 11 is concentrically formed on the cylindrical inner peripheral surface 3A of a cylindrical permanent magnet 3, and a magnetized part 12A for detecting the rotation and a magnetized part 13 for controlling the rotating speed are concentrically formed on the lower end surface, and a ring-shaped shielding member 5 made of a high magnetic permeability material is arranged between them. A leakage magnetic flux to the conductive pattern 14 of the magnetic flux of the magnetized part 13 and a leakage magnetic flux to a magnetic sensitive element 4A of the magnetized part 13 are magnetically shortcircuited by the operation of the member 5, thereby eliminating the interference between these magnetic fluxes to reduce the irregular rotation. |
