| 摘要 |
PURPOSE:To enable globe to be machined in high precision for a long period by engraving a V-shaped groove on the surface of a lower lap eccentrically against rotary axis, thereby suppressing abrasion of an upper lap. CONSTITUTION:While lapping powder being fed in the position of a globe 7, upper and lower laps 5, 6 are, respectively, rotated in the direction 10, 11, a V-shaped groove circle 13 on the lower lap 6 is rotated eccentrically against rotary axis line 14. Each of the globes is supported by three points, i.e. the lapping surface 12 of the upper lap 5, and both side walls of the V-shaped groove 13 and moves round by turning. However, since lapping speeds at these three points differ from each other, slipping motion takes place between the globe 7 surface and the upper and lower laps 5, 6, the globe 7 moves along the V-shaped groove 13. The whole surface of the globe 7 is uniformly lap- finished, its specified sphericality is attained, and moreover, abrasive progress of lapping surface 12 is suppressed. |
