Designing Hydrodynamic Bearing

Important Factors for Designing Hydrodynamic Bearing:

Most Babbitt bearings are operated as hydrodynamically lubricated bearings and the design considerations for hydrodynamic bearings are significant as well. To ensure minimized friction and bearing wear, the bearing material for hydrodynamic bearings should have moderate shaft deflection and adequate strength at operating temperature conditions. At the hydrodynamic bearing inlet, there must be continuous and adequate supply of clean and cool oil.

Principles of Journal Bearing Design

The role of a bearing is to provide relative positioning and rotational freedom while transmitting the load of the shaft to the bearing housing. The factor, which controls the length of the bearing to journal diameter, is known as the L/D ratio. When this ratio is greater than unity, it results in a long bearing, while a ratio less than unity would result in short bearings.

The deflection produced by the journal within the bearing can adversely affect its load carrying ability. This deflection can be greatly reduced by increasing the diameter and decreasing the length of the journal. 

Composition of Babbitt Materials

Babbitt alloys possess excellent conformability and embeddability. These materials are not used in applications where operating temperatures exceed 300°F, but have relatively low compressive and fatigue strength. The commonly used compositions of bearing materials are:

• Tin-base babbitts with 89% Sn, 8% Pb and 3% Cu
• Lead-base babbitts with 75% Pb, 15% Sb and 10% Sn
• Copper alloys such as Cu- 10% to 15% Pb

Babbitts can also be made of other materials, such as tin or leaded bronze, copper lead alloy, aluminum bronze or alloys, and cast iron, which are widely used in many applications.

Bearing Materials

An integral part of designing a bearing is selecting the material, since the bearing materials constitute an important part in the journal bearing. This maxim is particularly important for Babbitt bearings. The materials that are chosen are especially significant when considering the beginning of the hydrodynamic lubrication process, when contact occurs between the rotating shaft and the bearing. The bearing materials must be soft enough to resist the wear and endure load under gas pressure. In addition, they must also possess good compressive and fatigue strength. 

Characteristics of Bearing

As one of eight special industries in Linqing city, the bearing industry started early and had rapid development. It has a history of more than 50 years. The Yandian bearing market has developed into a specialized market which has the largest scale and the most complete variety. Besides, it has the most professional personnel listed on the market. Currently, the market covers an area of 1200 acres, with the building area of 320,000 square meters. There are about ten thousand business models of bearings in this market.

Bearing Manufacturing Process

At present, parameters of the internal structure of China's sealed deep groove ball bearings are almost the same as that of foreign products. However, the level of vibration and noise of such products is very different from that of foreign products. It is mainly resulted from the manufacturing factors and working conditions. From the point of view of the bearing industry, the working condition factors can be considered through making reasonable demands on the main engine. However, how to reduce vibration and noise that are caused by the manufacturing is become an urgent problem for the bearing industry.