| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor built-in spindle device which prevents the seizure of a bearing by suppressing a rise of temperatures of the bearing and a rotating shaft caused by the heat generation of a rotor, and can improve processing accuracy.SOLUTION: In an axial direction, an external peripheral side annular groove 76 and an internal peripheral side annular groove 77 are formed at an internal peripheral face and an external peripheral face of a rotating shaft 12 only between a front-side bearing 50 and a position in which a rotor 20 is fit to the rotating shaft 12, and only between a rear-side bearing 60 and a position in which the rotor 20 is fit to the rotating shaft 12. Carbon fiber composite materials 73 whose heat transfer coefficients are smaller than that of the rotating shaft 12 are arranged in the external peripheral side annular groove 76 and the internal peripheral side annular groove 77.SELECTED DRAWING: Figure 3 |
