Patent ID: 7273436

Claim:
A planetary-roller-type continuously variable transmission comprising: a planetary-roller speed-increasing mechanism whose input shaft is a carrier and whose output shaft is a sun roller; a planetary-roller speed-reduction mechanism whose input shaft is a sun roller and whose output shaft is a carrier; and a roller ring driving mechanism for rotationally driving a roller ring which is in contact with planetary rollers of the planetary-roller mechanism positioned at the output side from among the planetary-roller speed-increasing mechanism and the planetary-roller speed-reduction mechanism, wherein the output shaft of the planetary-roller speed-increasing mechanism and the input shaft of the planetary-roller speed-reduction mechanism are linked, or the output shaft of the planetary-roller speed reduction mechanism and the input shaft of the planetary-roller speed-increasing mechanism are linked, and wherein at least one of the planetary-roller speed-increasing mechanism and the planetary-roller speed-reduction mechanism includes a friction drive system that limits slippage among a planetary roller, a sun roller, and a roller ring by a frictional force generated therebetween, and wherein the roller ring, in contact with planetary rollers of the planetary-roller mechanism positioned at the input side from among the planetary-roller speed-increasing mechanism and the planetary-roller speed-reduction mechanism, is placed in a state wherein outer splines provided on the outer circumference thereof are engaged with inner splines provided on the inner circumference of a housing and which allows a motion in the radial direction.