HIGH-PERFORMANCE GEAR OIL FOR INDUSTRIAL GEARBOX APPLICATIONS Industrial gearboxes are expected to perform under conditions of high heat and heavy loads; and in environments often contaminated with dirt, process debris and water. Without adequate protection, gears will wear prematurely. You will have to replace parts more frequently, change oil more frequently, and worst of all, you’ll experience equipment downtime. 1. As pure sliding with any lubricating medium between the moving surfaces. 2. With hydrodynamic lubrication where a film buildup of lubricating medium is produced. 3. With hydrostatic lubrication where a lubricating medium is introduced under pressure between the moving surfaces. 4. With a combination of hydrodynamic and hydrostatic lubrication. Antifriction bearings minimise friction by removing any possible sliding between bearing surfaces and replacing all contacts with rolling interfaces. They substitute balls or rollers for a hydrodynamic or hydrostatic fluid film to carry loads with reduced friction. They utilise a separator to space the hardened rolling elements apart. Below is a summary of the advantages and disadvantages of plain bearings when compared with antifriction bearings: • The gear oil must remain thermally stable and not oxidize at high temperatures, thus avoiding the creation of sludge or varnish. Keeping the oil from oxidizing will lengthen drain and replacement intervals. As a general rule of thumb, for every 18 degrees F (10 degrees C) increase in fluid temperature above 140°F (60°C), oxidation will reduce the service life of a lubricant by half. • If you have an enclosed gearbox application that is heavily loaded or subject to shock loading, you need gear oil with extreme pressure properties. Gear oil with an EP additive will protect the gear surfaces against extreme pressures. • Gear oil must fight contamination that enters the system, especially water. The oil must be able to demulsify, which allows for easy removal of the water from the gearbox. Bearings provide either a sliding or a rolling contact whenever relative motion exists between parts of a machine. Sliding contact bearings are referred to as plain bearings and rolling contact bearings are often called antifriction bearings. Bearings that provide sliding contact fall into three general classes: radial bearings that support rotating shafts; thrust bearings that support axial loads on rotating shafts; and linear bearings that guide moving parts in a straight line. Radial bearings are also called sleeve bearings and they can either be full journal bearing or partial journal bearing. The former has 360° contact with its mating surface where the latter has less than 180° contact. The relative motions between the mating surfaces of a plain bearing may take place in the following ways: Gear oil is made up of two critical components: base oil and additives. Additives impart desirable properties and suppress undesirable ones. The additive package is the backbone of the lubricant’s performance, and a strong backbone will provide the performance and protection you need. When selecting gear oil, there are three essential attributes to consider: DUOLEC: ADVANTAGE DISADVANTAGE Quieter in operation High friction between mating surfaces result in high power consumption. Lower cost More susceptible to damage from impurities in lubrication system. Require less space More susceptible to damage from impurities in lubrication system. Bearing Life is not limited by fatigue Have more stringent lubrication requirements. THE GOOD OIL ON BEARINGS 20 July 2017
EN-July2017-eMag6
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