Double-speed-ratio speed reducer for coal mine well hoisting winch

The invention provides a double-speed-ratio speed reducer for a coal mine well hoisting winch, and relates to the technical field of speed reducers. The problems that helical teeth on a worm are prone to fracture due to overlarge fatigue in the using process, oil flushing of a gear cannot be achieved in a linkage mode, a fixing plate is only fixed through bolts, and no auxiliary alignment and fixing structure exists are solved. The double-speed-ratio speed reducer for the coal mine well hoisting winch comprises a main body plate, wherein the fixing plate is fixedly connected to the main body plate, and a transmission box is further fixedly connected to the main body plate; a first winding roller and a second winding roller are rotationally connected to the fixing plate and the transmission box, and a limiting cleaning structure is further rotationally connected to the fixing plate and the transmission box. Due to the fact that a gear F is meshed with a gear E and a gear G, when an adjusting rod rotates, a rot