고속 주축의 진동 특성 향상을 위한 베어링의 위치 선정

This paper presents analysis of dynamic characteristics of a high-speed milling spindle with a built-in motor. The spindle system with a built-in motor can be used to simplify the structure of machine tools, to improve the machining flexibility of machine tools, and to perform the high speed machining. In this system the shaft is usually assumed as a rigid rotor. In the spindle system design, it is very important to improve modal characteristics, and modal analysis is performed in the first place. Therefore in this paper, on the assumption that supporting bearings of spindle was selected most suitable condition, analyzed dynamic characteristics of a high-speed spindle according to its position. Optimal design was applicated to select most suitable position of bearings. Considered the mass and stiffness effects of the built-in motor`s rotor are analyzed by numerical method. The result shows the natural frequency of 1st bending mode of spindle.