Porous circulation precise air floatation shaft system

The utility model discloses a porous circulation precise air floatation shaft system, and aims to provide an air floatation shaft system with uniform air gaps. The utility model relates to an air-cooled spindle, which comprises a spindle (9) arranged in a shaft sleeve (8) and end covers (5) fixed at the two ends of the spindle, a radial air gap (14) is arranged between the shaft sleeve (8) and the spindle (9), an upper end air gap (3) and a lower end air gap (11) are respectively formed between the two end covers (5) and the two ends of the spindle (9), and a pressure air chamber (13) in the shaft sleeve (8) is respectively communicated with the radial air gap (14), the upper end air gap (3) and the lower end air gap (11). The pressure air chambers (13) in the shaft sleeve (8) are evenly distributed around the axis of the shaft sleeve (8), the top ends and the bottom ends of the pressure air chambers (13) are communicated with the upper end air gap (3) and the lower end air gap (11) respectively, and the pres