| 摘要 |
PROBLEM TO BE SOLVED: To high-efficiently manufacture a two-point support structure having a middle run-off through a comparatively simple method as bearing performance is improved. SOLUTION: A core rod 22 is inserted in a material (a sintered substance) 1A uniform in an outside diameter and provided at one end part in an axial direction with the small part 3 of an inside diameter and the material 1A is pressed in the cavity of a molding hole 20 by an upper punch 23. By compressing the outside diameter surface of one end part in an axial direction of the material 1A is compressed toward the inside diameter side and its outside diameter is reduced and meanwhile, the outside diameters of the central part and the other end part in an axial direction is increased. Along with this deformation, the inside diameter surfaces of two end parts in an axial direction are forced into pressure contact with the core rod 22 and formed on respective pivotal support surfaces 12 to support a rotary shaft, and a middle run-off 13 which has an inside diameter larger than that of the pivotal support surface 12 and with which a rotary shaft makes no contact is formed between the pivotal support surfaces 12.
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