High-precision rotary cylinder

The invention discloses a high-precision rotary cylinder. The high-precision rotary cylinder comprises a cylinder body. A gear shaft is installed at the center of the cylinder body and connected with a rack. An air inlet is formed in the cylinder body. A rack end cover is arranged at the tail end of the rack. The rack end cover is located to the cylinder body through threads. Lock pins are arranged on the inner side of the cylinder body and beside the gear shaft. The central axes of the lock pins pass through the central axis of the gear shaft. Each lock pin is connected with a piston through a screw. A lock pin end cover is arranged at the tail end of each lock pin. Each lock pin end cover is fixed with a check ring through a hole. Anti-rotation pins are installed on the cylinder body and prevent the lock pins from rotating. The high-precision rotary cylinder can accurately rotate by 90 degrees. Meanwhile, the high-precision rotary cylinder can bear heavy-load cutting and be widely applied to the occasion where 90-degree rotation is needed at a computerized numerical control (CNC) machining center. Five product surfaces can be machined at a time when the high-precision rotary cylinder is used in cooperation with a four-axis numerical control indexing plate, and therefore the machining efficiency is greatly improved.