| 摘要 |
PURPOSE:To enable accurate, short-time assembly without galling nor movement by forming the center hole of a polygon mirror and a motor shaft in conforming projection-recess shapes of different size, positioning them by matching the projection-recess shapes, and rotating and engaging projection parts. CONSTITUTION:The center hole 1a of the polygon mirror 1 consists of two peripheral surfaces where three projection parts 1b and recessed parts 1c are formed alternately, the engagement surface 2b of a flange part 2 consists of recessed parts 2d and projection parts 2e similar to the hole 1a, and the inner periphery of the center hole 1a and the outer peripheral surface of the engage ment surface 2b have the same diameter and minimum clearance. Therefore, when the projection parts 1b and recessed parts 2d are matched with each other and the flange part 2 is rotated by 60 deg., the projection parts 1b and projec tion parts 2e can be engaged in the minimum clearance state. Then the fixation member composed of a pressure spring member 4 and a stopper member 5 is assembled to enable accurate coupling without causing the movement of the mirror nor the galling of the hole part. |
