Electrical propulsion system including a plurality of electric motors coupled to the same input shaft of a transmission system, aircraft including at least one such electrical propulsion assembly

An electrical propulsion assembly including:

• a propeller having a rotation axis;
• at least two electric motors;
• a main drive shaft parallel to the rotation axis of the propeller;
• a transmission system configured to couple each electric motor to the propeller and including an output shaft connected to the propeller and an input shaft connected to the main drive shaft;
• wherein the at least two electric motors are coupled to the main drive shaft and offset relative to one another in a longitudinal direction parallel to the rotation axis of the propeller;
• wherein the electrical propulsion assembly includes, for each electric motor, a secondary drive shaft, and a coupling system coupling the secondary drive shaft and the main drive shaft, the secondary drive shaft being tubular and connected to the electric motor, coaxial and concentric with the main drive shaft;
• wherein a rear secondary drive shaft of the secondary drive shafts and a rear coupling system of the coupling systems is farthest from the transmission system, and a front secondary drive shaft of the secondary drive shafts and a front coupling system of the coupling systems is nearest the transmission system;
• wherein the secondary drive shafts are coaxial and concentric;
• wherein each secondary drive shaft has a constant inside diameter, and the secondary drive shafts are arranged such that the inside diameters increase from the front secondary drive shaft to the rear secondary drive shaft;
• and
• wherein each coupling system has an exterior surface connected to the corresponding secondary drive shaft by a permanent coupling and an inside surface connected to the main drive shaft by a permanent coupling, the coupling systems each having a substantially constant thickness, the coupling systems arranged so that the thicknesses of the coupling systems increase from the front coupling system to the rear coupling system.