US Patent 11566657 Vibration resistant torsionally compliant transmission shaft

A transmission shaft is provided comprising an input side for inputting torque, an output side for outputting torque, and a rod extending in a longitudinal direction between the input side and the output side to transfer torque along the transmission shaft. The rod comprises a first end provided at the input side, a second end provided at the output side and a torsional compliant section extending therebetween providing the transmission shaft with a torsional stiffness. The torsional compliant section comprises a cross-section which extends in the longitudinal direction to define a central core for transmitting torque directly from the first end to the second end and a radially outer section. This section also comprises a plurality ribs which extend radially and longitudinally from an outer periphery of the central core for increasing transverse stiffness of the rod.