To provide a pre-load variable type spindle capable of improving processing accuracy as a proper pre-load amount is always applied to a bearing, without being affected by a shaft weight even if the attitude of the spindle is changed from a vertical attitude to a horizontal attitude.
In the pre-load variable type spindle 10 in which a pre-load is applied to a front side bearing 13 by spring force of a spring member 45 via a sleeve 15, the spring member 45 is interposed between a hydraulic piston 43 fitted in a hydraulic chamber 41 and the sleeve 15. When the spindle 10 is in the vertical attitude, the spring member 45 is contracted by the hydraulic piston 43, so that pre-loads applied to the front side bearing 13 and a rear side bearing 14 are set. Further, when the attitude is changed to the horizontal attitude, pressure of hydraulic oil to be supplied to the hydraulic chamber 41 is controlled to extend the spring member 45, so that spring force acting on the sleeve 15 is changed to reduce the pre-loads and a pre-load amount of the front side bearing 13 associated with the attitude change of the variable pre-load type spindle 10 is properly maintained.
| JP3612783 | Main shaft device |
| JPH0735682 | [Name of invention] Spindle with built-in motor |
| WO/2021/054369 | ROTARY SHAFT MEMBER SUPPORTING DEVICE AND GRINDING MACHINE |
| JPS6432917U | 1989-03-01 | |||
| JP2005177908A | 2005-07-07 | |||
| JPH0724604A | 1995-01-27 | |||
| JP2010052100A | 2010-03-11 |
Hironori Honda
Toshimitsu Ichikawa