Abstract:Aimed at the shortcoming of the precision machine tool spindle composed of two static gas radial bearings,shch that the installation accuracy is difficult to guarantee and it can not realize selfaligning,a new gas bearing spindle supported by hydrostatic gas radial and hemispherical bearings was designed.Based on the maximum load and stiffness principle,the structure of the static pressure gas radial and hemispherical bearings was designed and optimized.The flow field characteristics of radial bearing and hemispherical bearing were analyzed by Fluent software to obtain the bearing characteristics of radial and hemispherical bearings under different eccentricity and speed.The results show that the bearing capacity of radial bearing and ball bearing is increased with the increase of eccentricity and gas pressure,and the stiffness is increased with the increase of gas supply pressure,but decreased with the increase of eccentricity.When the gas supply pressure is 0.5 MPa and the eccentricity is 0.5,the bearing capacity and static stiffness of the spindle can meet the requirements of precision machining.