Multi-shaft differential gear

The invention provides a multi-shaft differential gear. The multi-shaft differential gear comprises a primitive I, a primitive II, a primitive III,..., a primitive N-2 and a primitive N-1 which are sequentially connected in series, wherein N is a positive integer larger than or equal to 4; main rotation centers of all the units are coaxially arranged; the primitive I comprises a primitive I firststraight-tooth sun gear, a primitive I second straight-tooth sun gear and a primitive I transverse shaft; the element I transverse shaft is a main rotating shaft of the primitive I; the primitive I first straight-tooth sun gear and the primitive I second straight-tooth sun gear are arranged on the primitive I transverse shaft in a sleeving mode and rotate around the primitive I transverse shaft; the structures of the primitive II, the primitive III,..., and the primitive N-2 are the same; the primitive I transverse shaft is fixedly connected with an inner gear of the primitive II; and the connection modes among the pr