**Talking About Gas Lubricated Bearings** Home > Bearing Knowledge > Discussion on Gas Lubricated Bearings *Created on 2018/5/16* var cpro_id = "u3440131";

Talking About Gas Lubricated Bearings

---

/*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';

Gas lubricated bearings are a type of plain bearing that uses gas as the lubricant. They rely on the properties of gas such as its dispersibility, viscosity, and thermal conductivity, along with adsorption and compressibility. These bearings operate between two surfaces under the influence of hydrodynamic pressure, static pressure, and shear effects, maintaining a stable film that supports loads and reduces friction. Gas lubricated bearings can be broadly categorized into three types: gas dynamic pressure bearings, gas static pressure bearings, and gas squeeze film bearings. The operation of these bearings involves a mix of dynamic, static, and shear conditions, resulting in a complex but effective lubrication state. ### Key Characteristics of Gas Lubricated Bearings 1. **High Speed**: For example, helium turbo expanders can reach speeds of up to 650,000 rpm, with linear speeds of 238 m/s and dn values exceeding 455 x 10^6 mm·rpm. 2. **Precision**: The thin gas film allows for error compensation, offering accuracy that is two orders of magnitude higher than rolling bearings. This results in minimal vibration and high stability. 3. **Low Friction**: The viscosity of gas is only one-thousandth of that of oil, leading to significantly lower frictional torque—three orders of magnitude less than oil-lubricated bearings. 4. **Wide Temperature Range**: Gas bearings can function at temperatures as low as 10K or as high as 300–500°C, making them suitable for extreme environments. 5. **Environmentally Friendly**: Since they typically use air or inert gases, there is no pollution from the lubricant. Additionally, they produce low noise and minimal vibration, contributing to a cleaner working environment. 6. **Long Life**: Static gas bearings, which prevent direct metal-to-metal contact, have theoretically infinite life. Under normal conditions, their service life often exceeds 10,000 hours. Dynamic pressure bearings may experience wear during start-up and shutdown, with typical lifespans over 3,000 hours. ### Limitations of Gas Lubricated Bearings 1. **Lower Load Capacity**: Compared to oil-lubricated bearings, gas bearings have much lower load capacity. While oil bearings can handle 0.5–2 MPa, gas bearings typically manage only 0.02–0.04 MPa. 2. **Unstable Operation**: Gas bearings can suffer from issues like air hammer oscillation and eddy instability, reducing their reliability. 3. **High Manufacturing Cost**: Due to the need for precise manufacturing, especially for small holes and porous materials, production costs are relatively high. 4. **Strict Operating Conditions**: These bearings require a clean environment and strict adherence to operational procedures to avoid failures, which limits their widespread use. ### Applications of Gas Lubricated Bearings Gas lubricated bearings are commonly used in machine tool spindles, including workpiece shafts, tool shafts, and grinding wheel shafts. Two main types are used: pneumatic hydrostatic bearings and hybrid dynamic pressure bearings. Small high-speed spindles may also use foil bearings. Among these, gas static pressure bearings are most widely used, particularly those with small holes and porous structures. In recent years, porous gas hydrostatic bearings have become increasingly popular in machine tool applications. Hybrid bearings and floating ring dynamic pressure gas bearings are newer developments, ideal for high-speed spindle support. Ultra-high-speed air-bearing internal grinding heads can now perform fine grinding on small holes with remarkable precision, improving machining accuracy by up to 23 times and enabling Mirror-like surface finishes.

---

**Recommended for Friends** Comments | Close Window

Bearing Related Knowledge

Spherical bearing industrial transfer vehicles are widely used in ports. FAG thrust ball bearing skills analysis: FAG bearing repair and removal methods. Replacement of skating bearings when needed. Bearing cage data skills.

This article links to http:// Please indicate the bearing network http://

Previous: Bearing Work View | Next: Rolling Bearing Stop View

Laminated Glass

Laminated Glass,,Bullet Proof Glass,Ultra Clear Laminated Glass

SHANDONG TOP LEADER GLASS CO.,LTD , https://www.topleaderglass.com