Main shaft system of three-shaft thread rolling machine

The utility model discloses a main shaft system of a three-shaft thread rolling machine. The main shaft system comprises a main rotating shaft and a bearing seat, the outer surface of the main rotating shaft is sequentially sleeved with a first bearing, a second bearing, a thread rolling wheel and a pressing cover from right to left, bearing space rings are arranged between bearings of the first bearing and the second bearing and the outer wall of the main rotating shaft, an oil injection hole is formed in the top end of a bearing seat, and oil guide openings are symmetrically formed in the edges of the top end and the bottom end of a ring body of each bearing space ring. Annular grooves are annularly distributed in the side wall of a ring body of the bearing space ring; lubricating oil can smoothly enter a lubricating point, the oil way path is shortened, the risk of unsmooth oil ways is reduced, circulating center water cooling can be carried out under the cooperation of the swivel joint and the cooling ste