Compressor Tilt Pad Radial Bearing: Basic Composition and Working Principle

1. Basic Composition of Tilt Pad Radial Bearing

Tilt pad radial bearing is a type of bearing with exquisite design and excellent performance, mainly composed of multiple independent pads. These pads are evenly distributed within the circumference of the bearing, forming a complete and flexible support system. Each pad is connected to the bearing seat through a specific fulcrum, so that the pad can swing around the fulcrum during operation.

The material of the pad is usually selected with high strength, high wear resistance and good lubricity to ensure that the bearing can maintain stable performance during long-term operation. The surface of the pad is usually finely processed to reduce the surface roughness and increase the contact area with the lubricating oil, thereby enhancing the lubrication effect.

In addition to the pad, the tilt pad radial bearing also includes components such as the bearing seat, the fulcrum structure, and the lubricating oil system. The bearing seat, as the supporting base of the entire bearing, needs to have sufficient rigidity and stability. The fulcrum structure is responsible for connecting the pad and the bearing seat and allowing the pad to swing during operation. The lubricating oil system is responsible for delivering the lubricating oil to the gap between the bearing and the journal to form an oil film and realize liquid friction.

2. Working principle of tilting pad radial bearing

The working principle of tilting pad radial bearing is based on the theory of liquid hydrodynamic lubrication. Its core lies in forming a stable and uniform oil film to support the journal and realize liquid friction.

When a rotating machine such as a compressor starts to run, the journal starts to rotate at high speed. At this time, the lubricating oil is injected into the tiny gap between the bearing and the journal. Due to the high-speed rotation of the journal, the lubricating oil is subjected to shear force, begins to flow in the gap and gradually forms a continuous oil film. This oil film has sufficient thickness and strength to withstand the load of the journal and transfer it evenly to the bearing seat.

During operation, each pad can flexibly adjust its tilt angle according to the displacement and deformation of the journal. This adaptability is a major feature of tilting pad radial bearings. When the journal is slightly displaced or deformed for some reason, the pad will swing accordingly to keep the thickness and shape of the oil film stable. This adaptability enables the bearing to adapt to various changes in the journal, thereby ensuring the stability and reliability of the lubrication effect.

The formation of the oil film and the adaptability of the pads work together to give the tilting pad journal bearing excellent performance. The oil film not only holds up the journal and realizes liquid friction, but also plays a role in lubrication, cooling and cleaning. Compared with dry friction, liquid friction has less friction resistance and lower wear rate, which improves the operating efficiency of the bearing and extends its service life.

The adaptability of the pads enables the bearing to absorb and dissipate vibration energy. When a rotating machine such as a compressor vibrates, the bearing can consume the vibration energy through the swing of the pads and the squeezing of the oil film, thereby reducing the vibration level of the entire machine. This anti-vibration performance is crucial for the stable operation of the compressor.