Abstract: A dynamic pressure type bearing is applicable to a precision mechanical equipment. The bearing includes a hollow inner cylinder to fit a rotatable shaft. The inner cylinder is made of a thermosetting resin containing a 5 wt % to 75 wt % heat treated phenol resin powder and a 5 wt % to 75 wt % silicon dioxide, the total content of the phenol resin powder and the silicon dioxide being 50 wt % to 80 wt %. A spindle unit includes the bearing and a spindle made of an alloy containing aluminum as a main element. The bearing has a superior wear resistance, frictional characteristic and molding accuracy of the inner cylinder. The superior frictional characteristic of the inner cylinder allows a relatively soft spindle to be used in a spindle unit.

Abstract: A housing has a vertically extending cylindrical bore, with a radical bearing surface formed on the inner peripheral surface, and a thrust bearing surface formed on the inner bottom surface of the cylindrical bore. A shaft member which is supported rotatably in the cylindrical bore of the housing has a radial receiving surface and a thrust receiving surface respectively formed on the outer peripheral surface and the bottom surface. A dynamic pressure generating groove of a spiral shape is formed in at least one of the radial bearing surface and ther radial receiving surface. When the shaft member is rotated, a gas in the housing is sucked by the pumping action of the dynamic pressure generating groove and flows into a pressure chamber between the thrust bearing surface and the thrust receiving surface through a radial space between the radial bearing surface and the radial receiving surface. The pressure in the pressure chamber maintains the shaft member in a floating position by a predetermined amount.