The working principle of the air compressor is that a pair of mutually parallel male and female rotors (or screws) rotate in the cylinder, so that the air between the tooth grooves of the rotors constantly produces periodic volume changes, and the air is transported from the suction side to the output side along the rotor axis, thus realizing the whole process of suction, compression and discharge of the screw air compressor. The air inlet and air outlet of the air compressor are located at both ends of the shell, and the grooves of the mother rotor and the teeth of the rotor are driven by the main motor to rotate.