Torque transmission system having multiple torque transmission pathways from a driving shaft to a driven shaft, and a vehicle

A torque transmission system comprising:

• a driving shaft extending longitudinally along an axis of rotation upwards from bottom to top in an elevation direction from a lower segment to an upper segment with an intermediate segment extending between and connecting the lower segment to the upper segment of the driving shaft;
• a hollow driven shaft mounted to move in rotation about the axis of rotation, the driven shaft comprising longitudinally a first segment connected to a second segment, the first segment disposed inside the driving shaft, the second segment disposed outside the driving shaft;
• the transmission system further comprising an upper bearing co-operating with the upper segment and a lower bearing co-operating with the lower segment;
• the torque transmission system further comprising:
• a nominal spline coupling comprising main splines on the intermediate segment that mesh with main splines on the first segment in a nominal operating mode without any failure;
• a backup spline coupling between the driving shaft and the driven shaft, the backup spline coupling disposed above the nominal spline coupling in the elevation direction and in view of the axis of rotation, the backup spline coupling being inactive in the nominal operating mode;
• and
• a backup radial guide device disposed between the driving shaft and the driven shaft, the backup radial guide device disposed below the nominal spline coupling in the elevation direction and in view of the axis of rotation, and the backup radial guide device being inactive in the nominal operating mode.

A torque transmission system comprising a driving shaft and a driven shaft, the driving shaft being hollow and mounted to move in rotation about an axis of rotation, the driving shaft extending along the axis of rotation upwards from bottom to top in an elevation direction from a lower segment to an upper segment via an intermediate segment, the driven shaft comprising a first segment integrally connected to a second segment, the first segment arranged inside the driving shaft, the second segment arranged outside the driving shaft, and the transmission system further comprising an upper bearing co-operating with the upper segment and a lower bearing co-operating with the lower segment;

• wherein the torque transmission system further comprises:
• a nominal spline coupling comprising main splines on the intermediate segment that are active and mesh with main splines on the first segment in a nominal operating mode without any failure;
• a backup spline coupling between the driving shaft and the driven shaft, the backup spline coupling being arranged above the nominal spline coupling in the elevation direction and in view of the axis of rotation, and the backup spline coupling being inactive in the nominal operating mode;
• and
• a backup radial guide device between the driving shaft and the driven shaft, the backup radial guide device being arranged below the nominal spline coupling in the elevation direction and in view of the axis of rotation, and the backup radial guide device being inactive in the nominal operating mode.