Patent attributes
A small-bored cylindrical bearing member which can enhance the maintainability for a lubricating oil therein. The member has blind grooves in a seamless cylindrical central body portion of the interior hollow cylindrical surface of the bearing member. A method of manufacturing the cylindrical bearing member having blind grooves with blocked-in end portions extending in the longitudinal direction of the cylindrical portion and spaced from the ends of the member. The grooves can be easily formed in the central body portion of the inner circumferential cylindrical surface of the central body portion with the blocked-in ends spaced from the opposite ends of the seamless bearing member. The seamless member is first formed with a tapered or flared portion at one open end which is later narrowed into a round cylindrical form. Before narrowing the tapered or flared portion, the blind grooves are formed by a groove punch pushed through the open end into the central body cylindrical portion. After narrowing, the blind grooves have blocked end portions spaced from the opposite ends of the bearing in the longitudinal direction.
