Planetary roller transmission

A planetary roller transmission comprising:

• a lidded housing;
• a fixed ring provided in the housing with a central axis extending horizontally;
• a sun shaft provided on an inner side, in a radial direction, of the fixed ring concentrically with the fixed ring;
• a plurality of planetary rollers interposed between the fixed ring and the sun shaft;
• a carrier that has a plurality of support shafts that support the planetary rollers via bearing portions and that revolves together with the plurality of planetary rollers;
• and
• an annular flange ring provided on one side, in an axial direction, of the fixed ring and the planetary rollers, wherein:
• an inside diameter of the flange ring is smaller than a diameter of a circumscribed circle circumscribed by the plurality of bearing portions which are arranged in a circumferential direction;
• an oil storage portion that receives oil that has climbed over the flange ring from a side of the planetary rollers is provided between a side surface of the flange ring and an inner wall surface of the housing;
• and
• a passage that allows oil to permeate from the oil storage portion to the side of the planetary rollers is provided
• the housing is provided with an oil discharge hole that discharges oil to an outside, the oil discharge hole opening at the same height as a region on a lower side of a passage region through which the bearing portions pass in the case where the planetary rollers revolve.