DYNAMIC PRESSURE GAS BEARING DEVICE

摘要

PROBLEM TO BE SOLVED: To improve stability of rotation and reliability, in a dynamic gas bearing device. SOLUTION: A shaft 4 in an outer peripheral surface 4b of which a radial dynamic pressure generating groove 9 is formed is fixed on the upper surface of a thrust flange 3 through a protrusion shaft part 4a. A sleeve 7 integrally situated at a hub 5 is rotatably engaged with the shaft 4 and fixed at the hub 5. An approximate annular thrust bearing plate 8 having a hole in which the protrusion shaft part 4a is inserted and dynamic pressure generating grooves 10a and 10b in a thrust direction formed in upper and under surfaces is situated such that it enters a gap between the under surface of the bearing 4 and the upper surface of the thrust flange 3. In this case, by forming a radial dynamic pressure generating groove 11 also in an inner peripheral surface 7a of the sleeve 7, a radial dynamic pressure is increased when the sleeve 7 is relatively rotated based on the shaft 4, and improvement of rotation stability and reliability is practicable.