The cycloid rotor makes a planetary motion in the pump cavity, which makes the volume of the working chamber change periodically to realize the pumping. In the pump cavity, the surfaces of the moving parts are sealed with oil film, so the cycloid vacuum pump is an oil sealed mechanical vacuum pump. It is mainly composed of pump body and rotor. The profile of the rotor is cycloid, and the profile of the pump cavity is the envelope of the rotor profile. The internal gear on the rotor is meshed with the pinion fixed on the pump cover.

When the rotating shaft rotates, the eccentric wheel drives the internal gear to make planetary movement around the small gear, and the pump body points always contact with the rotor surface, and the pump cavity is divided into chambers a and B. When rotating in the counter clockwise direction, the pressure in chamber a gradually decreases, and the gas is continuously inhaled from the suction port. At the same time, the gas in Room B is gradually compressed and discharged out of the pump through the exhaust valve.

Compared with the same type of pump, cycloid pump has many advantages in terms of structure, principle and performance

1. Stable operation, small vibration, small size and large pumping speed;

2. In the low pressure range (1-100pa), its pumping speed field curve is due to the slide valve pump;

3. It is not sensitive to certain amount of dust and small particles in the extracted gas;

4. To adapt to the working environment with higher temperature, the pump chamber can be kept at a higher temperature by the temperature control device to extract a large amount of condensable steam.

Because the cycloid pump still has a large pumping speed in the pressure range of 1-10 PA, the pump is suitable for large displacement device in vacuum industry. At present, it has been applied in vacuum metallurgy, vacuum heat treatment, vacuum drying and other industries.