METHOD FOR MANUFACTURING SINTERED BEARING WITH INTERIOR CIRCUMFERENTIAL GROOVE AND GROOVE WORK DEVICE

摘要

PROBLEM TO BE SOLVED: To be able to pull out securely a core rod used for forming an interior circumferential groove from bearing material having a less or almost no spring- back, and, as a result, to form securely the interior circumferential groove in such bearing material. SOLUTION: By pressing a part of the outer surface of the bearing material 10 with a rubber pattern 33 of a rubber press mechanism 30 toward shaft center of a core rod 20F, operation to impress a part of a larger diameter section 21 of the core rod 20F into the inner surface of the bearing material 10 by radial compression is repeated sequentially throughout the periphery of the bearing material 10 circumferentially. Thereby, an inside diameter of a bearing surface 12 of the bearing material 10 is allowed to be equivalent to or larger than the larger diameter section 21 of the core rod 20F and the core rod 20F can be made extractable.