Bearings, bushings, shaft seals, oil seals

In rotating equipment, bearings are classified into radial bearings and thrust bearings based on their function; the former serve to support the rotor, while the latter are used for the axial positioning of the rotor. Bearings are classified into rolling bearings and sliding bearings based on their type, with bearing bushes belonging to the sliding bearings and serving to support the rotor. The shaft seal refers to the seal at the end of the rotor, and its function is to prevent the leakage of the medium. There are various types of such seals, including packing seals, mechanical seals, comb tooth seals, dry gas seals, and floating ring seals. An oil seal is the bearing-end seal of the rotor, serving to prevent the leakage of lubricating oil; it is generally a packing seal or a comb-tooth seal. Installation depends on its structural form: the cylindrical type is inserted from the shaft end, while those with a mid-surface can be installed on the side.

In rotating equipment, bearings are classified into radial bearings and thrust bearings based on their function; the former serve to support the rotor, while the latter are used for the axial positioning of the rotor. Bearings are classified into rolling bearings and sliding bearings based on their type, with bearing bushes belonging to the sliding bearings and serving to support the rotor. The shaft seal is the seal at the end of the rotor, and it serves to prevent leakage of the medium either outward or inward. In terms of design, there are packing seals, mechanical seals, comb tooth seals, dry gas seals, floating ring seals, and others. An oil seal is used for sealing the shaft end of a bearing; it operates by creating an oil film at the shaft end to achieve sealing.

It is mainly to create a proper oil film around the shaft as it rotates, thereby reducing vibration during rotation

I still don’t quite understand. Is the shaft seal a seal at the end of the rotor, near the impeller or on the other end? And what’s its relationship with the bearing installation? Are oil seals present in both the front and rear bearings? It would be good to have an assembly diagram to look at :)

The shaft seal is used to seal the outer diameter of the shaft; the other end you mentioned might be a thrust bearing.

Do you mean that the shaft seal is used to seal the medium? Commonly used ones are generally packing-sealed mechanical seals and skeleton seals!

It depends on the equipment; some models have only one seal in the entire unit. I’ve repaired an imported 3-screw lubricating oil pump, and it also had just one seal!

Bearings generally include radial bearings and thrust bearings. The function of a radial bearing is to support the rotor enabling it to rotate at high speeds, while the function of a thrust bearing is to prevent the rotor from moving sideways and to maintain its axial position. Bearing bushes protect the bearings by keeping them aligned with the axis. Shaft seals include packing seals and mechanical seals.