Cycloid reducer is a poor use of KHV few teeth novel principle of planetary transmission gear. Its transmission process is as follows: the input shaft equipped with a 180-degree dislocation of the double eccentric sets, as are two eccentric put to the roller bearing arm, the formation of H, the two cycloid round hole at the centre which is eccentric upload sets of roller bearings Arm Road, and the needle round by the cycloid of meshing gears, gear components for the poor meshing slowdown in the body.