| 摘要 |
PROBLEM TO BE SOLVED: To provide a main spindle device capable of restricting unevenness of dynamic characteristics around the main spindle to the minimum by controlling the pre-load of a bearing and capable of stable cutting independently of a cutting mode by controlling the pre-load by considering the direction of the cutting force in addition.SOLUTION: In the main spindle device, the main spindle 2 is rotatably supported by a housing through an angular ball bearing, and a pre-load is applied to a spacer of the angular ball bearing. An outer ring spacer 8 as a part of the spacer is equally divided into eight in the circumferential direction of the bearing. The main spindle device includes a pre-load control section to control the pre-load to be applied to each of the divided spacers 8a-8h. The pre-load control section obtains compliance and cross-compliance of the main spindle 2 and the direction of the cutting force to be applied to the main spindle 2 during the cutting operation, and controls the dynamic characteristic of the spindle 2 by changing the pre-load of each of the divided spacers 8a-8h. |
