Patent ID: 6626020
Filing Date: 2003-09-30
Classification: B21J,B21K,F16F,Y10T

Abstract:
A method of producing a vibration-insulating bushing, comprising:providing a cylinder having an outer circumference on which a rubber elastomer is secured by vulcanization molding; and submitting an axial extremity of the cylinder to upsetting by cold plastic working comprising: (i) pressing a top surface of an upsetting jig onto an edge surface of the axial extremity of the cylinder, said top surface of the jig having a flattened conical surface with no elongated projection its center and having a constraint wall formed around the flattened conical surface for restricting the outward widening of the edge surface of the cylinder while moving the jig; (ii) moving the jig along the edge surface of the axial extremity of the cylinder, wherein the axis of the jig moves in a conical orbit around and on a point where the axis of the jig and the axis of the cylinder intersect, thereby widening the edge surface of the inner cylinder in an outward direction; and (iii) continuing the moving of the jig until the edge surface of the cylinder contacts the constraint wall and begins extending inward, thereby narrowing an inner diameter of the edge surface of the cylinder.