Welding, positioning and clamping mechanism for automobile tail door

The invention discloses a welding, positioning and clamping mechanism for an automobile tail door, and belongs to the technical field of automobile part machining. A turnover plate with a clamping assembly is arranged on a transfer frame and used for clamping the upper end face and the lower end face of the edges of the two sides of a tail door frame; the opposite end faces of the upper clamping plate and the lower clamping plate are provided with an upper profiling groove and a lower profiling groove which are matched with the upper end face and the lower end face of the end edge of the tail door frame correspondingly, the contact tightness with the tail door frame can be improved, and compared with simple pressing and positioning of a pressing plate, the clamping stability is improved; welding operation of different parts is completed in a front-back conveying mode, machining operation of an assembly line is achieved, a lifting structure is additionally arranged on each welding station, an overturning plate