Large-span gantry machining center cross beam structure

The utility model discloses a cross beam structure of a large-span gantry machining center. A cross beam body comprises a front side wall, a rear side wall, an upper side wall, a lower side wall, a left side wall and a right side wall, an upper guide rail mounting surface, a rack mounting surface and a lower guide rail mounting surface are arranged on the front side surface of the front side wall;the height difference between the upper guide rail mounting surface and the lower guide rail mounting surface is matched with the height difference between the upper sliding block and the lower sliding block; stand column joint mounting surfaces are symmetrically arranged at the bottom of the lower side wall; the height difference between the upper surface of the upper side wall and the stand column joint installation face is 1.5-1.9 times of the height difference between the upper guide rail installation face and the lower guide rail installation face, and the length of the cross beam body is 5.0-7.0 times of the he