Automatic separating device for sphericity error of large-scale ball and method thereof

The invention discloses an automatic separating device for a sphericity error of a large-scale ball and a method of the automatic separating device. A single-shaft air floating table and an air floating plate are utilized for replacing the function of a roundness measuring instrument to detect the sphericity error. The air floating flat plate is used for adjusting the eccentricity of the rotation axis of an air floating ball center and the eccentricity of the rotation axis of the single-shaft air floating table. An arc support is fixedly connected with a shaft sleeve base of the single-shaft air floating table. A micrometer dial is installed on the arc support to ensure that a sensitive direction of a measuring head points to the ball center. According to the automatic separating device, the function relationship between reading of the micrometer dial and the rotation angle of the single-shaft air floating table, an altitude angle where the micrometer dial is located, a dip angle rotation error of the single-shaft air floating table, a radial rotation error, an axial rotation error, an installing eccentricity error of the floating ball and the sphericity error of the air floating ball is set up, and then the error separating method is designed according to the function relation. The sphericity error of the large-scale ball can be detected, the measurement precision is 0.4 micrometer, and the sphericity error can be separated more accurately and conveniently and faster.