Power drive system for road vehicles

A power driven system for road vehicles, in particular public transportation and semitrailer vehicles in combination with the body and suspension structure of the vehicle, comprising at least one prime motor supported on the body structure of the vehicle and utilising a first type of energy source, at least one hydraulic pump on said body structure and driven by said prime motor thereby to convert the energy of said motor into first pressure fluid energy, at least one primary motor supported on said body structure at a distance from said prime motor and utilising a second type of energy source different from said first one, at least one second hydraulic pump on said body structure and driven by said primary motor thereby to convert the energy of said primary motor into second pressure fluid energy, at least one differential gear on at least one axle of said vehicle and at least one hydraulic motor transmissively connected with said differential gear, controllable means being provided connecting said first and second hydraulic pumps with said at least one hydraulic motor thereby to convey selectively said first and said second pressure fluid energy from said hydraulic pumps to said at least one hydraulic motor, said hydraulic motor driving said differential gear and the axle and the wheels mechanically connected therewith.