| 摘要 |
PROBLEM TO BE SOLVED: To provide a pre-load adjustable spindle in which, even if the posture of a spindle changes, a proper pre-load value is applied to a bearing at always without affected by a shaft weight, for improved precision in working. SOLUTION: In a pre-load adjustable spindle 10, a pre-load is applied on a front side bearing 13 by the spring force of a spring member 45 by way of a sleeve 15. The spring member 45 is interposed between an oil-pressure piston 43 that engages with an oil pressure chamber 41 and the sleeve 15. By contracting/expanding the spring member 45 by controlling the pressure of a working oil that is supplied to the oil pressure chamber 41, the spring force acting on the sleeve 15 is changed, to properly keep the pre-load value on the front side bearing 13 which is determined by change in posture of the pre-load adjustable spindle 10. COPYRIGHT: (C)2012,JPO&INPIT |
