| 摘要 |
PURPOSE:To restrict vibration by providing radial bearing surfaces and thrust bearing surfaces to a housing member so that they are opposed to a spindle, and providing a clearance possessing damper-oil between the midposition of the radial bearing surfaces in two places and the shaft part of the spindle. CONSTITUTION:On the upper and lower end faces of the inside peripheral surface of a housing 3, gas bearing elements 4, 4 made of porous material are fixed, and the inside peripheral surfaces of the gas bearing elements 4, 4 are used as radial bearing surfaces 5, 5, while the sides of these elements are used as thrust bearing surfaces 6, 6. A shaft part 8, flange parts 9, 9 of a shaft member 7 inserted inside the housing 3 are respectively opposed to the radial bearing surfaces 5, 5 and the thrust bearing surfaces 6, 6. At mid-position of the radial bearing surfaces in two places, a recessed groove 24 is formed over the full length of the periphery of the shaft part to obtain the oil-storage effect and the sealing effect, and damper-oil 19 is held in a clearance between the shaft part 8 and the groove. Since the damper is located close to the radial bearing surfaces and at the portion of high bearing rigidity, vibration due to surface- deflection can be restricted. |
