High-sensitivity pressure-limiting air valve of truck air pump

The invention discloses a high-sensitivity pressure-limiting air valve of a truck air pump and belongs to the field of automobile parts. A conical lower cover with a large opening facing upwards is installed on a pipe joint, a disc-shaped rubber pad is installed on the lower cover, a cylindrical plastic push rod is vertically installed in the center of the bottom of the rubber pad, and a spiral pressure spring is installed between the lower portion of the interior of the lower cover and the bottom of the rubber pad. A conical upper cover of which the edge with a large opening facing downwards is meshed with the upper part of the lower cover is arranged on the rubber pad, and an upper cover external thread is arranged at the top end of the upper cover; when the air pump enables the pressure of air filled into the air storage tank to reach the upper limit, the air storage tank inputs air pressure into the upper cover through an air return pipe, the air pressure pushes a rubber pad to move downwards to compress a pressure spring and pushes a plastic push rod downwards to abut against an air inlet valve piece of the air pump downwards, and the air inlet valve piece of the air pump cannot be closed; therefore, the air pump cannot normally inflate air.