Radial piston damped torsional coupling and machine using same

A machine comprising:

• an engine with a drive shaft;
• a hydraulic piston pump with a pump shaft;
• the drive shaft being torsionally coupled to the pump shaft by radial piston damped torsional coupling;
• and
• a damping liquid source fluidly connected to a radial variable volume chamber of the radial piston damped torsional coupling;
• the radial piston damped torsional coupling including a first coupler attached to the drive shaft, a second coupler attached to the pump shaft, and one of the first coupler and second coupler including a plurality radially oriented pistons and barrels with contact ends in contact with respective non-circular flutes on a fluted perimeter surface of an other of the first coupler and second coupler;
• and
• a torsional stiffness adjustor that includes a damping liquid pressure regulator.

A method of driving rotation of a work shaft, comprising the steps of:

• applying a torque from a drive shaft to the work shaft through a radial piston damped torsional coupling;
• the applying step includes rotating a first coupler relative to a second coupler away from a neutral torque orientation;
• rolling a roller of one of the first coupler and the second coupler back and forth in a non-circular flute that follow a contour of a superellipse of a fluted perimeter surface of an other of the first coupler and the second coupler responsive to a torsional vibration;
• and
• damping relative rotation of the first coupler relative to the second coupler by displacing damping liquid by moving a piston relative to a barrel.