Frictional drive unit

A frictional drive unit, comprising:

• a frame;
• a pair of drive disks rotatably supported by the frame, arranged coaxially, and opposed to each other;
• a plurality of drive rollers provided on an outer circumferential portion of each drive disk and arranged at intervals in a circumferential direction of the drive disk, each drive roller being supported to rotate around an axis inclined relative to the circumferential direction of the drive disk;
• a pair of actuators configured to independently rotate the pair of drive disks;
• and
• a main wheel formed in an annular shape, arranged between the pair of drive disks, coming into contact with the drive rollers, and configured to rotate around a central axis and an annular axis,
• wherein each drive roller includes a roller shaft and a round roller body provided on an intermediate portion of the roller shaft,
• each drive disk includes plural pairs of bearing grooves each receiving both ends of the roller shaft of each drive roller, and
• bearing grooves open toward the main wheel.