Tailstock pre-tightening device of turning center

The utility model discloses a tailstock pre-tightening device of a turning center. The tailstock pre-tightening device comprises a shell, a pre-tightening force adjusting part, a spring, a bearing seat and a pre-tightening wheel, wherein the shell is provided with an inner cavity; the pre-tightening force adjusting part, the spring and the bearing seat are sequentially arranged in the inner cavityof the shell from bottom to top; and the pre-tightening force adjusting part is used for pushing the spring to ascend to drive the bearing part and the pre-tightening wheel arranged on the bearing seat to ascend vertically. By adjusting the pre-tightening force adjusting part, the spring is compressed to push the bearing seat to ascend, the pre-tightening wheel abuts against the bottom of the machine body guide rail to form a pre-tightening force, and when the tailstock moves, the pre-tightening force ensures that the tailstock is always attached to the machine body guide rail in a pressing mode, so that a gap betwee