| 摘要 |
PURPOSE:To remove uneven load at zooming, to reduce noises and to prevent image vibration and image fading by arranging plural bearings so that each bearing is brought into contact with only one side of a groove. CONSTITUTION:Two bearings B2a, B2b are formed on one groove by using a shaft 6 as a coaxial. The B2a and B2b are brought into contact with the left groove surface 3a and the right groove surface 3b respectively and engaged with each other through spacers 5a, 5b. Since only one out of the bearings is allowed to contact with one side of the groove, load unevenness and refractive resistance at the time of loading are reduced and a clearance between the bearing and the groove side can be kept at a small value. >=2 bearings may be adopted, and in this case, at least one bearing should be allowed to contact with each of two sides of the groove respectively. The bearings 2a, 2b are engaged with the shaft 6 through eccentric shafts 8a, 8b respectively. |
