Gearless differential speed reducer structure

A gearless differential speed reducer structure comprising:

• a crank-shaped eccentric shaft having input and output ends, and disposed to receive a rotary movement;
• a second disc fixed to a stationary member in a manner to rotationally admit said eccentric shaft through a central hole provided within said second disc;
• an epicycloidal-related groove provided on a facing surface of said second disc to run continuously along a predetermined circle with a single wave as a lobe;
• a first disc rotationally mounted on said output end of said eccentric shaft through a bearing to adjacently face said surface of said second disc;
• a hypocycloidal-related groove provided on a facing surface of said first disc to run continuously along a predetermined circle with a single wave as a lobe;
• both said grooves being recessed in a direction perpendicular to the surface of said discs and having two opposed side walls of the same height and the width of each groove being uniform through the lobes thereof;
• rollable balls located on the groove of said first and second discs with the spherical surfaces thereof always contacting the walls of each groove and rolling along the grooves thereof upon actuation of said eccentric shaft, converting rotary movement of said first disc into a rotation component and a revolution component;
• a rectifier disc rotationally mounted on a shaft to face another surface opposite the grooved surface of said first disc so as to provide a speed reduction output;
• a rectifier means provided between said first disc and said rectifier disc to absorb the revolution component of said first disc and to transmit only the rotational component to said rectifier disc;
• and
• the difference between the number of lobes of said first disc and that of said second disc being two.