1. Technical Field
The invention relates to a ball joint, especially for steering and transmission rods of motor vehicles. The ball joint includes a bearing shell made of plastic which has a lower shell and an upper shell for the support of a ball head in a joint housing. The lower shell is turned toward a housing opening for a ball stud, and the upper shell is supported against a housing cover through a spring element. The lower shell is joined elastically with the outer rim of the upper shell.
2. Background Art
From German Disclosure 2,405,160 is known a ball joint of this kind. The ball joint includes a lower shell and an upper shell which are joined and sealed together by a circumferential elastic joining. The elastic joining includes a sealing lip of the upper shell made of elastic material. The sealing lip sealingly engages in a ring groove on the upper rim of the lower shell. For this purpose, the sealing lip is inserted in the ring groove under the pressure of a closing cover.
The mounting of this previously known ball joint is expensive because the upper shell and lower shell must be assembled, and are only secured after rolling in the closing cover. Also, the upper shell made of an elastomer material has poor friction, wear and fatigue properties. This may lead to a change of its prestress and the operation characteristics of the ball joint.
In German Disclosure 2,913,700 is disclosed a ball joint having a lower shell and an upper shell. The upper shell is supported by a spring against a housing cover. On the upper shell are formed axially directed flanges which engage form-fitting in corresponding openings of the lower shell. However, the form-fitting connection between the lower shell and the upper shell exists only with the ball joint assembled, and must be produced in the mounting.