Device and method of producing ball joint

Abstract

A ball jointincludes a first memberhaving a ball sectionand a second memberhaving a socket. Ball sectionis accommodated and supported inside socket. A pair of diessandwich a wallsurrounding an openingof the socket, and are configured to approach each other gradually, utilizing small repetitive vibrations that include an approaching and separating action, thereby intermittently pressing the wall in an inward radial direction. During each interval of the intermittent pressing action, a supporting and rotating devicerotates socket(second member) in small increments about a central axis Cof socket. Consequently, diesandsuccessively press against a multitude of points on the circumference of the outer surface of wallof the socket, thereby bending wallinward so as to reduce the diameter thereof.