ROTATION MECHANISM AND INTERNAL UNIT OF ROTATION MECHANISM

摘要

A rotation mechanism includes: a casing which is configured to be vertically split into two portions and includes an upper half portion on the upper side and a lower half portion on the lower side; an internal unit which is disposed in the casing and has a configuration in which a rotor which rotates around an axis thereof, a bearing portion which rotatably supports the rotor, and an annular seal portion which seals a gap surrounding a circumferential surface of the rotor so as to enable the rotor to rotate are integrated; an axial movement restricting portion which includes a fitting concave portion provided on one of the casing and the internal unit and a fitting convex portion provided on the other thereof to be fitted into the fitting concave portion as a pair and restricts relative movement between the casing and the internal unit in a direction of axis; and a tapered surface which is formed on each of the fitting concave portion and the fitting convex portion so that a width thereof in the direction of axis increases toward an inner circumferential side in a radial direction.