Standard unit mechanism in automobile welding fixture

The utility model provides a standard unit mechanism in an automobile welding fixture. The standard unit mechanism in the automobile welding fixture comprises an angle seat and a support plate which is arranged on the angle seat. A support block is arranged on the support plate, the support plate is movably connected with a clamping arm by a connecting plate, a clamping block is arranged on the clamping arm, the support plate is connected with an air cylinder, and the clamping arm is connected with an air cylinder head. The standard unit mechanism in the automobile welding fixture has the advantages of being capable of simultaneously achieving positioning and clamping functions, being capable of being adapted to positioning and clamping of plates of different bore diameters, being low in machining cost, reducing design period, reducing non-standard machining parts, shortening manufacturing period, increasing welding space position of an operator, being capable of enabling the air cylinder to prevent welding s