Friction drive device and transmission using the friction drive device

A friction drive transmission for transmitting torque by frictional contact between rollers, the friction drive transmission comprising:

• a casing;
• a drive roller supported for relative rotation with respect to the casing, the drive roller including a first plurality of different diameter rollers;
• a driven roller supported for relative rotation with respect to the casing, the driven roller including a second plurality of different diameter rollers;
• a cam mechanism pressing the drive roller and the driven roller into contact with each other, the cam mechanism including:
• a cam surface disposed at an angle with respect to a tangent of the contact between the drive roller and the driven roller;
• and
• a rotational support part being disposed on the surface and supporting one of the drive roller and the driven roller, wherein displacement along the cam surface by the rotational support part maintains the frictional contact for transmitting the torque;
• a damper reducing vibration of the rotational support part;
• and
• a shifter selectively and independently contiguously engaging one of the first plurality of different diameter rollers with a corresponding one of the second plurality of different diameter rollers.