Main shaft rear end internal oil blocking structure

The utility model relates to a main shaft, in particular to an oil blocking structure inside the rear end of the main shaft. A spindle core of the spindle penetrates through the water jacket, the oil cylinder assembly is arranged at the rear end of the spindle, the piston is arranged in the oil cylinder assembly, one end of the fixing ring is fixed to the end face of the rear end of the water jacket, and the oil cylinder assembly is fixed to the other end of the fixing ring. A movable ring is arranged between the fixed ring and the shaft core in a spaced mode, the movable ring is fixed to the outer wall of the shaft core and rotates along with the shaft core, an oil collecting ring groove is formed in the end face, facing the piston, of the fixed ring, and a radial protruding ring is arranged at the end, facing the piston, of the movable ring and extends to the outer side of the oil collecting ring groove. A gap with an L-shaped section is formed among the movable ring, the radial convex ring and the fixed ri