rotor, with the meshing helical teeth gradually detached, a section of the volume is formed between the two teeth in the expanded cavity (the cavity between teeth for short), and the external gas is continuously inhaled until the helical teeth mesh again, thus completing the process of inhalation. When the cavity between the teeth moves to the exhaust end along the rotation axis of the rotor, as the exhaust port is set in a small space, the volume of the cavity between the teeth is gradually reduced due to the constant meshing of the two spiral teeth before the cavity is communicated with the exhaust port, so as to achieve the purpose of compressed gas and complete the gas compression process. Finally, the cavity between the teeth is communicated with the exhaust port, and the compressed gas is discharged from the body to complete a working cycle.