Patent ID: 6105250
Filing Date: 2000-08-22
Classification: B22F,F16C,Y10T

Abstract:
A method of producing a hydrodynamic pressure type porous bearing, comprising the steps of;forming a cylindrical porous material having at one end a larger-outer-diameter portion and at the other end a smaller-outer-diameter portion whose outer diameter is smaller than that of the larger-outer-diameter portion,forming an outer peripheral surface of a core rod with a pair of axially spaced forming portions for forming bearing surfaces having axially inclined hydrodynamic pressure generating grooves,placing the core rod in an inner peripheral portion of the porous material such that an inner peripheral surface of the larger-outer-diameter portion and an inner peripheral surface of the smaller-outer-diameter portion are opposed to the forming portions of the core rod, respectively, whereupon with this state maintained, the porous material is pressed into a forming hole having a cylindrical portion smaller in diameter than the larger-outer-diameter portion and a drawing portion decreased in diameter to be smaller than the smaller-outer-diameter portion,radially inwardly pressurizing the larger-outer-diameter portion of the porous material by the cylindrical portion of the forming hole and the smaller-outer-diameter portion of the porous material by the drawing portion of the forming hole, respectively, so as to press the inner peripheral surfaces of the larger and smaller-outer-diameter portions against the forming portions of the core rod, thereby forming the respective inner peripheral surfaces with said bearing surfaces having shapes corresponding to the forming portions.