The cover engages round all the rotating parts lying in the transmission path between engine (13) and drive axle (16) and round the drive axle itself at least on the top and side faces. The cover interacts with the otherwise supporting and lining vehicle parts so that the rotating parts are still only accessible from below. The cover can engage from above and at the sides round the engine shaft. A first belt disc (20) is fixed on it, and there is a drive axle, a second belt disc (21) fixed on it and a drive belt (22) tensioned between the two belt discs.
