Planetary transmission speed reducer for sand mixer

The invention provides a planetary transmission speed reducer for a sand mixer, and belongs to the technical field of speed reducers, the planetary transmission speed reducer comprises a box body and a multi-stage planetary transmission structure in the box body, the whole speed reducer is vertically arranged, an output shaft is arranged on the upper portion, and an input shaft is arranged on the lower portion; an oil pool and an oil conveying pipe are arranged outside the box body; an oil hole a, an oil hole b and an oil hole c are formed in the box body, an oil pump is arranged outside the oil pool, the oil conveying pipe is communicated with the oil pool, the output shaft is connected with the box body through a bearing a, a bearing b and a bearing c, the oil hole a, the oil hole b and the oil hole c correspond to the bearing a, the bearing b and the bearing c respectively, and the oil hole a, the oil hole b and the oil hole c are communicated with the oil conveying pipe through an oil hole d. An oil outle