Patent attributes
Herein disclosed is a shaft sealing apparatus which comprises a vacuum casing formed with a vacuum chamber, a driving shaft having an outer cylindrical surface and movably extending in the vacuum chamber of the vacuum casing, and a sealing ring in the form of an annular ring shape and including a sealing lip held in contact with the outer cylindrical surface of the driving shaft, an annular spring member operative to impart a force to the sealing lip to ensure that the sealing lip is held in tight contact with the outer cylindrical surface of the driving shaft, and a peripheral portion radially outwardly extending from the sealing lip, in which the outer cylindrical surface of the driving shaft is smaller in surface roughness Ra than 0.1 (μm).