| 摘要 |
PROBLEM TO BE SOLVED: To provide a machine tool capable of simply preventing a rise in temperature of a bearing portion for supporting a tool holding shaft even if the tool holding shaft is continuously turned at high speed. SOLUTION: A lower end of the tool holding shaft 3 having its upper end 3f disposed in a cavity 12 is fitted into and held by an angular ball bearing 2 of a head 1 having a bearing hole 13 for holding the angular ball bearing 2 and the cavity 12 where the bearing hole 13 is opened. A cylinder 7 opened in the cavity 12 for blowing the air out toward the upper end 3f is attached to the head 1. The tool holding shaft 3 is cooled by the air blown out from the cylinder 7, thereby preventing rise in the temperature of the tool holding shaft 3. In turn, rise in temperature of the angular ball bearing 2 portion is suppressed by the tool holding shaft 3. COPYRIGHT: (C)2013,JPO&INPIT |
