Cycloidal gear reducer is a principle adopted K-H-V Planetary Gear less innovative gear. Its transmission process as follows : input shaft equipped with a 180-degree dislocation of the double eccentric sets, replaced with two eccentric turn as a roller bearing arm, the formation of H-, two cycloid round hole at the center shall uplink Eccentric Roller Bearings arm, which cycloidal gear needle round and meshing phase, comprising a difference of the teeth meshing with the gearbox.