Motor drive/internal combustion engine rotor, when the tooth groove space of the master and slave rotors turns to the opening of the intake end wall, the space is large, and the outside air is filled in it. The air between the tooth grooves is sealed between the main and slave rotors and the casing to complete the suction process.

At the end of the suction, the closed volume formed by the tooth peaks of the main and slave rotors and the casing decreases with the change of the rotor angle, and moves in a spiral shape, which is the "compression process".

During the transportation process, the volume is continuously reduced, the gas is continuously compressed, the pressure is increased, and the temperature is increased. At the same time, the lubricating oil that has become misty due to the air pressure difference is sprayed into the compression chamber, thereby achieving compression, lowering the temperature, sealing and lubricating effect.

When the closed tooth crest of the rotor rotates to meet the exhaust port of the casing, the compressed air starts to be discharged until the matching surface of the tooth crest and the tooth groove moves to the exhaust end face. At the same time, another pair of tooth grooves of the main and slave rotors has rotated to the intake end, forming the largest space, and the suction process begins, thus starting a new compression cycle.