Speed reducer for compact mud extruder

The utility model provides a compact deceleration machine with a clutch in the box body for extruder, which comprises a box body, a box cover, a plurality of shafts, a plurality of gears, a spline housing and a bearing, and is characterized in that: the deceleration machine box body is a unitary rectangle box made in ways of seaming or founding and provided with five shafts which are a high speed shaft, an intermediate shaft, a low speed shaft and two stirring shafts respectively; the driving gear of the low speed shaft is arranged on the right end of the spline housing and connected with the spline housing by a crescent hook head button; by rotating the crescent hook head button, the driving gear can be stopped from running, thereby the two stirring shafts stop mixing materials. The utility model has the advantages of whole box, stabile structure, reliable performance, simple manufacturing process and less leakage; the rotating key clutch is arranged on the low speed shaft, which can effectively avoid the material jam phenomenon when the extruder squeezes out of the feed opening and guarantee the normal operation and security of the equipment.