For the stator curve of vacuum pump, there are the following requirements:

1. The blade has no impact vibration and good noise

The smooth stator curve can not have too large acceleration, too much acceleration will lead to the increase of pressing force on the surface of stator curve at one end of the rotor, which will increase the wear and noise. However, if the radial velocity 4) of a point on the stator curve changes, then the radial acceleration at that point. It's equal to infinity in theory. If a is infinite, the blade will break away at this point instantaneously and produce a great impact force. It causes a lot of noise and serious grinding. In order to eliminate this phenomenon, the stator curve is required to be smooth, continuous and smooth.

2. There is a large pumping rate

Without increasing the pump size, the volume area of the vane pump element should be increased as much as possible in order to obtain a higher pumping speed string.

3. Suitable distance between two points

Due to the integrated design of the blade, the rigidity is enhanced, and the expansion of one end will inevitably cause the corresponding expansion and contraction of the other end. Therefore, no matter the rotor turns to a certain angle, the curve must be in contact with both ends of the rotating blade at the same time, so as to keep a reasonable clearance, so as to avoid the phenomenon of void leading to the increase of discharge.

4. Make the rotary blade in good stress state

The angle between the vector diameter of a point on the stator curve and the normal of the point on the curve is the pressure angle of the stator curve. The increase of the pressure angle will increase the force of stator against the vane and the angle between the vane direction, increase the lateral force of the vane, increase the friction between the vane and the rotor, and worsen the stress condition of the blade, which will affect the service life and overall efficiency of the pump

At present, the stator curve of vacuum pump is mainly circular curve. It is mainly considered that the positive return curve has good speed and acceleration characteristics, which reduces the noise and impact during the working process of the vacuum pump. The new stator curve should not only increase the pumping rate, but also have the velocity and acceleration characteristics of the existing curve. The stator curve of a vacuum pump has a direct influence on its performance parameters such as pumping rate. Therefore, it is very important to obtain a good stator curve for the design of vacuum pump.