Ultrahigh-pressure spherical sealing structure with anti-extrusion function

The invention relates to an ultrahigh-pressure spherical sealing structure with an anti-extrusion function, and belongs to the field of static strength assessment tests of aerospace products. The external spaceflight product is divided into a flange structure and a nozzle structure, and when the external spaceflight product is of the flange structure, the spherical sealing structure comprises a sealing flange, a spherical check ring, an O-shaped rubber ring, a fastener and a filler neck; wherein the sealing flange is axially and vertically butted with an external spaceflight product; a sealing groove is formed in the butt joint position of the sealing flange and the external spaceflight product. The spherical check ring is arranged in a sealing groove of the sealing flange; the O-shaped rubber ring is embedded into the bottom of the spherical check ring; after the sealing flange and the external spaceflight product are in butt joint, a fastener sequentially penetrates through the sealing flange and the extern