Abstract: A circular groove present on a journal on its end is utilized to provide a bayonet coupling on the journal without mechanical refinishing work to fix or clamp a ring piece axially on the journal. The clamped supporting elements of the bayonet coupling are formed as a divided supporting ring whose collar engages in the circular groove and is rigidly nonrotatably held in it. The circumferentially divided supporting surfaces of the supporting ring are assembled by attaching members correspond in the locked configuration with the interiorly directed circumferentially divided abutting surfaces of the clamped ring piece which form the rotatable portion of the bayonet coupling.