Air compressor bearing temperature is too high solution

1. Increase the balance force and reduce the bearing force

The most direct way to increase the balance force is to increase the diameter of the balance hub, but the transformation is very difficult and the cost is high. After research, the pressure of the air chamber after the balance hub is reduced to a negative pressure, and the pressure difference between the front and rear of the balance hub is increased to improve the balance force. The volute of the air chamber behind the balance hub is drilled and connected to the primary air intake of the compressor with an inner diameter of 65mm, so that the balance air chamber is communicated with the primary air inlet to form a negative pressure, and the pressure difference between the front and rear of the balance hub is increased accordingly. When the balance force is increased, the force on the thrust bearing decreases. After testing, when the operating oil temperature is 45°C, the temperature of the thrust bearing at the TE218 measuring point is 93°C, and the temperature of the thrust bearing at the TE201 measuring point is 81°C.

2. Use the non-coincidental magnetic field lines of the motor to reduce the bearing force

Although the balance pipe solves part of the balance force, in order to achieve a complete balance, it is necessary to add a vacuum system, which requires additional equipment on the compressor, which is inconvenient to operate. When aligning the compressor unit, intentionally adjust the axial length of the coupling to the allowable larger size, and adjust the axial gap size of the coupling between the compressor and the speed-increasing machine to the upper limit of 1.7mm, and the motor The position of the magnetic force center line and the rotor center line deviates by 4mm, so that the magnetic force is opposite to the bearing force when the motor is running, and is transmitted through the elastic diaphragm coupling, which reduces the bearing force. After alignment, the temperature of the bearing at the TE218 measuring point was reduced to 90℃, and the temperature of the thrust bearing at the TE201 measuring point was 83℃, and the bearing force basically reached a balance.

However, after long-term operation, the temperature of both thrust bearings increased to varying degrees, 93°C at TE218 and 84°C at TE201. The compressor thrust bearing was overhauled and inspected, and it was found that the bearing pads were blackened, and there were yellowing and black carbon deposits in the middle of the thrust plate and the bearing seat, which required further analysis.