| 摘要 |
PURPOSE:To obtain a rotary supporting device for a polygon mirror which is hardly deformed irregularly even in the case of high-speed rotation by specularly machining an aluminum-made rotor itself and providing an intermediate ring between a ceramic-made rotor and the aluminum-made rotor. CONSTITUTION:The rotor 28 constituting a rotary body R is provided on the outer periphery of a shaft sleeve 27 of the outer periphery of a fixed shaft 25, and an upper thrust plate 29 and a lower thrust plate 30 are provided vertically across the rotor and receive a thrust load in the axial direction of the rotary body R. A yoke is provided by shrinkage fitting on the outer periphery of the lower part of the rotor 28, a magnet 33a is fitted inside a ring part 32 extending to below the yoke 31, and the aluminum rotor 33 which has a specular surface M on its outer peripheral surface is positioned above the yoke 31. The intermediate ring 34 is arranged between the rotors 28 and 33 and provided on the outer peripheral surface of the rotor 28 by shrinkage fitting, and the rotor 33 is provided on the outer peripheral surface of the intermediate ring 34 by shrinkage fitting. When the rotary body R rotates at a high speed, the quantity of elastic deformation due to the centrifugal force is reduced by the intermediate ring 34. |
