Automatic automobile tire inflation device

The invention discloses an automatic automobile tire inflation device. An internal thread which is connected with an automobile tire valve is arranged around the inner bottom of an outer cylinder; a valve needle pushing rod is fixedly arranged in the middle of the inner bottom of the outer cylinder; a piston is arranged in the outer cylinder and is in a hollow shape; a vent hole is formed in the middle of the piston; the upper, lower and middle parts of the piston are in contact with the interior of the outer cylinder respectively; the interior of the outer cylinder is divided into four different air pressure regions, namely a first air pressure region, a second air pressure region, a third air pressure region and a fourth air pressure region; a first one-way valve is arranged at the bottom of the piston; an air inlet is formed in a position, corresponding to the third air pressure region, on the outer cylinder; a second one-way valve is arranged at the air inlet; a pressure regulating spring is arranged on t