| 摘要 |
PROBLEM TO BE SOLVED: To provide a spindle device having a sufficient damping performance on a free side bearing and capable of obtaining a stable operation even at a high-speed rotation. SOLUTION: The spindle device 1 is equipped with a rotatable rotary shaft 2, a front side bearing 3 with an inner ring inner peripheral surface fitted to a front part of the rotary shaft 2 and an outer ring outer peripheral surface fixed to a housing 50, a rear side bearing 5 with the inner ring inner peripheral surface fitted to a rear part of the rotary shaft 2, a bearing sleeve 6 externally fitted to the outer ring outer peripheral surface of the rear side bearing 5, a plurality of hydraulic pistons 7 for applying a constant-pressure preload to the bearing sleeve 6, a hydraulic pump 8 for supplying a hydraulic working oil to the hydraulic piston 7, and throttle valves 27 provided between the hydraulic pump 8 and the hydraulic piston 7. The throttle valves 27 are provided at hole parts 37, 40, 9 communicating with a pressure chamber 25 disposed with the hydraulic piston 7. COPYRIGHT: (C)2009,JPO&INPIT
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