CORE ROD FOR FORMING BEARING SURFACE OF DYNAMIC PRESSURE TYPE POROUS OIL IMPREGNATED BEARING

PROBLEM TO BE SOLVED: To enable the precise formation of a bearing surface having dynamic pressure grooves on the inner peripheral surface of a cylindrical sintered metallic base stock formed into the bearing body of a dynamic pressure type porous oil impregnated bearing with a small man-hour. SOLUTION: On the outer peripheral surface 1a of a core rod 1 made of a cemented carbide, a forming part 1b having a first range 1b1 for forming the dynamic pressure groove on the bearing surface and a second range 1b2 for forming the range except the dynamic pressure groove, is arranged. The forming part 1b is formed by an etching. This core rod 1 is inserted into the inner diameter part of the sintered metallic base stock and the pressing force is applied on the sintered metallic base stock and the inner peripheral surface is pressurized to the forming part 1b of the core rod 1 to form the bearing surface having the shape corresponding to the forming part 1b on the inner peripheral surface.