Material Features of CSB-EPB series
CSB engineers are dedicated on the performance improvement on the self-lubricating materials derives the result that CSB-EPB Series Materials are with excellent self-lubricating features and wear resistance Features. High-strength fibers used in the engineering plastics fantastically improve the material load (Graph 1). Special grease immersion in the plastic can decrease the friction coefficient of the material therefore to prolong the bearing service life. High-performance engineering plastics body material mainly service as wear-resistant vector. The reinforced fiber improves the load and impact resistant capacity of the bearing. Special grease decreases the friction coefficient for a better self-lubricating performance.
CSB-EPB Series Bearing vs Metal Bearings
Because the grease immersed in the solid plastic material, the lubricating will be valid continuously no matter how long the bearings are working. Therefore, the traditional sintered oilless bearings provide the lubricating function by utilizing the impregnated oil in the tiny porosities of the material. When the impregnated oil would have been run out of dried, the bearing wear will be increased sharply and the bearing life will be terminated at the same time. (Graph 2).
CSB-EPB Series Bearing Friction Coefficient
The self-lubricating feature of the CSB-EPB bearing is achieved by adding solid lubricants and functional fibers into the body material and the friction coefficient is decreased by the solid lubricate grease immersion. The friction coefficient is affected by the load, operating speed and shaft roughness. The friction coefficient is generally decreased along the load increasing and increased along the operating speed (see Graph3). Please refer to Graph 3 for the relation between the friction coefficient and shaft roughness.
The Initial Run-in Wear of CSB-EPB Series
Slightly wear off will occur as soon as the self-lubricating bearing is applied with a certain load. It is the same to the CSB-EPB series bearings, when the slightly wear occurs, the immersed oil (grease) will infiltrate out from the bearing filling the wear off area of the bearing as well as the mating material to form the lubricating film (Graph 4) and therefore interrupt the wear process. In this way, the aforementioned working method of the plastic bearings improves the wear resistance feature of the bearings and maintains the further operation stable (Graph 5).
As the bearings wear resistance affected by many factors, it is difficult to accurately describe bearing wear and life span. Through numerous experiments we can conclude that the main factors affect the anti-wear property are the load, moving method, speed, roughness of mating surfaces, ambient temperature and dust and type of the outside lubricating medium, etc. When the load, speed and temperature increase, the wear resistance of bearings gradually reduced; when there is outside lubrication medium, the wear resistance could be doubled; CSB recommend the roughness of axis to be Ra0.2 ~ Ra0.8. If the shaft is too rough or too smooth, it might increase the wear. Although there is no special restriction on the using of shaft material for the CSB-EPB series bearings, CSB recommend the use of hard chrome plated shaft material. The recommended shaft hardness is over HRC35 in order to avoid the initial wear off on the shaft.