| 20100327486 | Manufacturing Method of Cylindrical Member and Manufacturing Method of Vibration Damping Rubber Bushing Having the Cylindrical Member - A method of manufacturing a cylindrical member having anti-slip projections formed on axial end faces, the method comprising the steps of: employing a roller die, which is provided with a circumferential die groove of annular form extending through a medial section in a generatrix direction of a die face defined by an integral tapered outside peripheral face, and with a plurality of sloping die grooves extending in a tapered slope direction of the die face situated to both large-diameter and small-diameter sides of the circumferential die groove; providing plastic working to the axial end face with the small-diameter side of the roller die facing towards an inner peripheral side of the cylindrical member and with the large-diameter side facing towards an outer peripheral side, by pushing the die face against the axial end face while rotating circumferentially; and forming simultaneously an annular water barrier projection and the anti-slip projections. | 12-30-2010 |
