Patent attributes
A speed reducer according to one aspect of the present disclosure includes: an input gear; a plurality of spur gears configured to rotate in mesh with the input gear; one or more eccentric cams formed on each of a plurality of shafts, each of the plurality of shafts being coupled to corresponding one of the plurality of spur gears; and one or more eccentric gears each having a plurality of first through-holes and a plurality of second through-holes, each of the plurality of first through-holes rotatably supporting corresponding one of the one or more eccentric cams, the second through-holes being disposed adjacent to the first through-holes and formed asymmetrically as viewed from a direction of a central axis, and the one or more eccentric gear are configured to rotate eccentrically relative to a rotational axis of the input gear in conjunction with rotation of the one or more eccentric cams.