| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide substantially uniform hardness, rigidity and a supporting force for a spindle in its entire operation range by attaching a spindle shaft to the inside of a housing frame and utilizing a static pressure bearing. SOLUTION: A spindle shaft 14 has static bearing pads 20 around both of front and rear ends 14a and 14b. Preferably, four pads 20 are formed at equal intervals around the front and rear ends 14a and 14b of the shaft 14. The axial direction distances of the front and rear bearing pads 20 are relatively short, and thus the spindle shaft 14 is attached to the inside of a housing 12 so as to have hardness and high-level motion rigidity even if it is rotary-driven by a motor 16. Further, the full length of the spindle shaft 14 containing a part protruded over a bearing 18 is relatively short. Thus, a high cutting speed and a load are dealt with and the resonance vibration of the shaft 14 is prevented while work piece precision cutting is provided.</p> |
