| 摘要 |
A cylindrical bearing member, which can hold lubricating oil in blind grooves as oil reservoirs for a long period of time to exhibit a lubricating function sufficiently, the blind grooves being efficiently mass-produced on the inside of the cylindrical member at low cost. The cylindrical bearing member has an inner circumferential surface having a plurality of blind grooves and is formed as a hollow open-ended cylindrical member with a bottom from a circular column-shaped crude material or blank. The blank includes a tapered inner circumferential surface at its open end. A groove forming die pin DP6 including groove forming protrusions DP62 is pushed from the open end towards the bottom to obtain a cylindrical member in which a plurality of grooves are formed on the inner surface. The grooving die pin is removed, then the tapered inner circumferential surface of the cylindrical member 107 is returned and straightened to a cylindrical shape to close the grooves at the open end of the member, and then the bottom is removed from the cylindrical member. A flared groove forming die pin may also be used. |
