Main shaft supporting device of screw medium-pressure machine

A main shaft supporting device of a screw medium-pressure machine comprises a shell and a main shaft, wherein a first tapered roller bearing, a second tapered roller bearing and a third tapered roller bearing are arranged on the shaft neck supporting surface of the rear end of the main shaft sequentially; the outer diameters of the first tapered roller bearing, the second tapered roller bearing and the third tapered roller bearing are fixed in shell mating holes; the first tapered roller bearing and the second tapered roller bearing are arranged in the same direction; the second tapered roller bearing and the third tapered roller bearing are arranged in opposite directions; an inner regulating ring is arranged between a first tapered roller bearing inner ring and a second tapered roller bearing inner ring; and an outer regulating ring is arranged between a first tapered roller bearing outer ring and a second tapered roller bearing outer ring. The device has the advantages of simple structure, convenience in m