Ball joint, in particular steering or suspension ball joint for motor vehicles and, method for making a bearing for same

A ball joint, especially a motor-vehicle steering or suspension ball joint, comprising a pivot provided with a spherical head, a ball-joint case provided with a housing to receive the pivot head, and a bearing shell of plastic material interposed between the pivot head and the case housing, wherein the bearing shell of the ball joint comprises a one-piece molded cup, closed at a bottom side and provided, by molding,

• with a spherical inside surface extending over a solid angle corresponding to more than one hemisphere,
• with a circular orifice, whose diameter is smaller than a diameter of the spherical inside surface and which is disposed opposite the bottom side, and
• with a plurality of rupture zones of small thickness distributed over a circumference of the orifice, while extending from the orifice toward an equatorial plane of the spherical inside surface disposed parallel to a plane of the said orifice, the rupture zones having a conformation that each undergoes predefined rupture into two sections during a first expansion of the orifice and that, after insertion of the head of the pivot into the bearing shell, elastic constriction of the orifice is permitted together with exact repositioning of the two sections of each rupture zone around the pivot head.