| 摘要 |
PURPOSE:To enhance coaxialness while using ceramic by forming the shaft supporting part and rotary shaft from ceramic, and by fitting a bearing ring of ceramic in each shaft supporting hole with a metal ring interposed. CONSTITUTION:Spindle table 7 of a lathe is formed of ceramic at its peripheral part, while the shaft supporting parts 8 are also made of ceramic. A shaft supporting hole 8 is provided in each shaft supporting part 8 prior to the baking process of ceramic. A metal ring 10 with small wall thickness is fitted by pressure in each shaft supporting hole 9, and the inner wall of this ring shall undergo an extra-precision processing for centering alignment. Thereafter a bearing ring 11 of ceramic is fitted in this metal ring 10, and a rotary shaft 12 of ceramic is fitted in this bearing ring 11 to be borne thereby. This extra-precision centering processing of the bore of the metal ring 10 assures high coaxialness with the bearing ring 11 of ceramic fitted therein. |
