Three-ring hypocycloid reducer

The involute teeth of an inner gear on a ring plate in the three-ring hypocycloid reducer are converted into novel teeth, namely ring swing teeth, which belongs to curtate hypocycloidal teeth, the central sun gear is converted into a pin gear, and the ring swing teeth is in mesh transmission with the roller pin teeth, thereby forming a novel reducer, namely the three-ring hypocycloid reducer. The teeth of the involute gear can slide and bend, and can not be provided with bearings. The ring swing teeth can not slide or bend, and can be provided with roller pins. Therefore, when being used for transmitting high-power, high-transmission-efficiency and low-noise data, the indices of the three-ring hypocycloid reducer rank first and exceed those of the three-ring reducer and the cycloid pin gear reducer. The invention has the advantages of short transmission route, small size, low manufacturing cost, high reliability, good maintainability and long service life. The first-stage transmission ratio can reach 120, the