The cycloidal pinwheel reducer is a novel transmission device that utilizes the K-H-V planetary transmission principle with a small tooth difference, as shown in the figure. The tooth difference between the sun gear (pin gear) Zz and the planetary gear (cycloidal gear) ZB is 1, i.e., Zz - ZB = 1. The transmission process is as follows: a double eccentric sleeve with a 180° offset is mounted on the input shaft. Two roller bearings, referred to as swing arms, are installed on the eccentric sleeve, forming the H mechanism. The central holes of the two cycloidal gears serve as the raceways for the swing arm bearings on the eccentric sleeve. The cycloidal gears mesh with a set of annularly arranged pin teeth on the true gear, forming an internal meshing reduction mechanism with a tooth difference of one tooth (to reduce friction, pin sleeves are used on the pin teeth in reducers with small speed ratios). When the input shaft rotates one full revolution with the eccentric, due to the characteristics of the tooth profile curve on the cycloidal gear and the constraints imposed by the pin teeth on the pin gear, the motion of the cycloidal gear becomes a planar motion with both revolution and rotation. When the input shaft completes one full revolution in the forward direction, the eccentric sleeve also completes one full revolution in the forward direction, while the cycloidal gear rotates in the opposite direction by one tooth, achieving speed reduction. Through the W output mechanism, the low-speed rotation of the cycloidal gear is transmitted to the output shaft via the pin shaft, resulting in a lower output speed.