Aluminum alloy rear auxiliary frame of double-arch structure

The utility model provides an aluminum alloy rear auxiliary frame with a double-arch structure, which comprises symmetrically arranged mounting seats, a rear cross beam, a middle cross beam and a front cross beam are sequentially arranged between the two mounting seats from back to front, any one mounting seat is an arch beam, and the other mounting seat is an arch beam. The two arched beams are respectively welded with the rear cross beam, the middle cross beam and the front cross beam through CMT to form a double-arched structure; any arched beam is of a C-shaped structure, an opening of the C-shaped structure faces the side away from the middle cross beam, an L-shaped supporting foot is arranged on the side, facing the middle cross beam, of the closed end of the C-shaped structure, and the included angle of the L-shaped supporting foot is an obtuse angle. The rear cross beam, the middle cross beam and the front cross beam are respectively welded with the two mounting seats to form a double-arch structure,