| 摘要 |
PURPOSE:To improve vibration controlling effect and reliability for various speeds of revolution by forming concave cavity on a bearing enclosure serving as an oil reservoir and disposing a floating bearing having a ball seat supporting a rotary shaft in the concave cavity. CONSTITUTION:A concave cavity 5 is formed on a bearing enclosure 1 serving as an oil reservoir 3 which is filled with lubricating oil 2, and a plurality of rider piece receiving members 6 and a bearing metal 10 are fixed in the concave cavity 5. A floating bearing member 15 is disposed in the concave cavity 5 with a gap 1b therebetween, and a ball seat 17 for supporting the end spherical dynamic pressure bearing portion 20a of a rotary shaft 20 is mounted at the central portion of the top surface of the floating bearing member 15. Thus, the rotary shaft 20 is started, oil is fed from a pump 32 to oil feed holes 13, 30, so that a turning force is received by both the dynamic pressure bearing portion 20a and the floating bearing member 15, and when the number of rotations increases, the pump is stopped, so that a turning force is received only by the dynamic pressure bearing portion. |
