The performance of OilLess Bearings can be greatly effected by surface roughness, the use of plated and non-plated surfaces and mating materials, which form the friction between the two solids.
Surface Roughness
In case of solid lubricant Bearings, like OilLess # ZA 500 and ZA#1000 their Bearing lives are determined by whether or not a lubricating film of solid lubricants can be formed on sliding surfaces of either mating materials or the Bearings. Surface roughness of mating materials within 3 ~ 12 micron meter is sufficient for proper performance of the Bearings. A mirror finish, as in the cases of oil lubricating Bearings and plastic Bearings, is not necessary.
Surface Treatment.
The three main reasons for treating mating surfaces are:
- To improve corrosion resistance.
- To improve surface hardness.
- To improve surface smoothness for better lubricity.
When plating is employed to attain purpose 1 above, hard chrome plating is highly recommended, because it prevents mating materials from rusting and abrasive wear from developing. hard chrome plating also contributes considerably to the lubricity improvement .For slight oscillating motions under high loads, nitriding treatment on shaft materials is effective. When used under highly corrosive environments such as in seawater, double or triple layered chromium plating is necessary.
Role of Oiling:
Periodical Oiling is suggested for OilLess Bearing because it will reduce co-efficient of friction and the Bearing temperature, thus improving the Bearing life. Oiling also facilitates performance under high load conditions and secures safety. Other advantages of Oiling include: removal of wear particles, sealing effect against foreign matters, prevention of rust on the shaft material, etc.
Lubricating Oil
In general, motor oil is used. However, grease is recommended for conditions where considerable vibration occurs which scatters oil, or a low speed operation under a high load, which disrupts a lubricating, oil film.
Grease
Grease is superior to lubricating oil in sealing effect, water-proofness and adhesiveness but is inferior in its cooling effect. Grease is often applied when Bearings are frequently splashed with water or where there is considerable vibrating or textile machine.
