Trailer hitch

The ball part (2) of the towing unit (1) can be either joined to the trailer or to the vehicle. The socket part (3) is assembled of two swivel mounted calotte-shaped parts (7, 8) which can be separated for the insertion of the ball (2). The inner surface of each of the parts (7, 8) is partly made of plane segments (24, 25, 27) and comprises an area with several grooves (28) to be used for lubrication. A dust receptacle (30) in the shape of a recess is also integrated in the inner surface of the socket part (3), keeping metal particles away from the moving parts.