Sankyo 11AR manual Lubrication, Purpose of lubrication, Oil selection precautions

Unit 7

Lubrication

7. Lubrication

Lubrication is an effective and vital means for maintaining the life of your SANDEX unit. Lubrication can minimize wear by reducing friction between rolling members, removing friction heat, and preventing rust on rolling surface. The statistical life of the SANDEX unit is based on rolling fatigue. However, these statistics are valid only when wear, vibration, and mechanical seizure are kept at a minimum.

Improper lubrication over any of these areas can cause frictional wear in a very short time.

On the other hand, proper lubrication using incorrect grades of lubricating oils, such as low viscosity oil, can cause temperature rises and lower the dynamic viscosity of the lubricant. This means that the minimum dynamic viscosity necessary for forming an oil film cannot be obtained, thereby allowing the two surfaces to directly come into contact and cause frictional wear.

It is vitally important that proper lubrication procedures be implemented according to actual operating conditions.

4.5Purpose of lubrication

(a)To prevent friction between pure slipping members.

(b)To prevent abrasion by forming an oil film between two surfaces, thereby inhibiting direct contact between both surfaces.

(c)To extend the fatigue life of the material by introducing boundary based on oil film formation, thereby relieving Hertz stress.

(d)To prevent local temperature rises by transmitting and removing friction heat.

(e)To prevent dirt and other foreign particles from entering the housing.

(f)To prevent rust by using the oil film to keep the surface from direct exposure to the atmosphere.

7.2Oil selection precautions

(1)Lubrication is a vital factor to ensure maximum performance from your unit. The selection of lubricating oils is equally important. Improperly selected oils can lower the precision of the unit, and reduce its operating life. When selecting an oil, always give full consideration to actual operating conditions.

(2)When selecting oils, choose good quality gear oil with pressure additives, a strong oil coating quality, rust inhibiting properties, and steady oxidation. (A pressure additive is a specially formulated chemical composition that improves lubrication performance.)

(3)Never mix oils of different manufacturers even if they are used for the same purpose. This is because each manufacturer may use pressure additives with different compositions.

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