Patent ID: 8123644

Claim:
A traction-drive type driving-force transmission mechanism comprising: a sun roller having a central axis and being rotatable about said first central axis; a plurality of planetary roller units each provided in such a manner as to be orbitally movable along an outer peripheral surface of said sun roller; and a pressing member which has a pressing surface surrounding said planetary roller units to press each of said planetary roller units toward the outer peripheral surface of said sun roller, and allows a driving force to be transmitted through means of a traction force between said sun roller and each of said planetary roller units, wherein each of said planetary roller units includes: first and second shaft members having respective first and second peripheral axes extending in parallel relation to said central axis and in spaced-apart relation to each other; a first planetary roller rotatably supported by said first shaft member, and adapted to be orbitally moved along the outer peripheral surface of said sun roller; and a second planetary roller rotatably supported by said second shaft member while allowing an outer peripheral surface thereof to be in contact with an outer peripheral surface of said first planetary roller and said pressing surface, and adapted, during orbital movement of said planetary roller unit along the outer peripheral surface of said sun roller, to press the outer peripheral surface of said first planetary roller against the outer peripheral surface of said sun roller.