Rear-floor spare tire well structure of sedan

The utility model discloses a rear-floor spare tire well structure of a sedan. The rear-floor spare tire well structure is characterized by comprising a bottom surface (1); the bottom surface (1) adopting a three-level stepped structure is concave step by step; a lug boss (2) is arranged at the central position of the bottom surface (1); a group of reinforcing ribs, namely concave ribs (3), are radially distributed in directions from the bottom surface (1) to a lateral wall in a pulling-through manner, and centered with the lug boss (2). The rear-floor spare tire well structure has the advantages that due to the staggered arrangement of the reinforcing ribs, the rigidity and the modality of a spare tire well are obviously improved; during welding, the problem of plastic deformation caused by treading on the spare tire well is solved; the NVH performance of the whole sedan is improved; the low frequency resonance phenomenon occurring during sedan driving is avoided; the risk that the spare tire well cracks during a road test is reduced; during electrophoretic coating, electrophoretic liquids are collected on the lowest central surface along the step surfaces of the concave ribs (3) and the bottom surfaces (1), so that one or two liquid leakage holes are reduced. Therefore, the quantity of blocking pieces and the cost can be reduced, and the rear-floor spare tire well structure is worth of industrial popularization and application.