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| Rolling bearing preserve natural resources | ||||||||||
Rolling bearings can play a mojor role in the preservation of natural resources by providing enhanced operating life, and also through downsizing as a result of the combination of improved materials and optimised designs. | ||||||||||
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Flaking caused by raceway surface defects can be improved by optimising the retained austenite content in bearing raceway surfaces. This results in reduced stress concentration from dents and, once again, improved life. The corollary of this is less demand on the environment, in terms of raw material usage and preservation of natural resources. Surface optimisation plays a key role in reducing demands on the environment through extended bearing life. However, it goes further by reducing the energy-consuming friction that ultimately leads to wear and, possibly, premature failure. For a surface design to ensure reduced friction and longer bearing life, machining processes (barrelling and honing) as well as surface roughness play important roles. A good surface geometry leads to optimum oil film formation, while the machining processes ensure good compressive stress levels and high resistance to abrasion and excessive wear. Complementing the role of surface optimisation, bearing design contributes greatly to energy conservation. Reducing the frictional resistance of rolling bearings is an endless challenge. Low torque designs that reduce friction have also been developed for more widely used ball bearings. These designs, which are complemented by new low torque contact seals and greases, are reducing torque by up to 50% in electric motors, a critical area of power consumption and accounting for 2/3 of all industrial usage. Low torque ball bearings have been developed to improve the efficiency of motors used in domestic appliances in order to reduce their power consumption. These types of bearings have the same outside diameters and width as the global standard 608 ball bearings, but have improved internal specifications, including ball diameter and PCD. Although the dynamic load of the new bearings is lower, this is not a problem as low torque is the main consideration. That this is achieved is evidenced by the fact that torque for these bearings is 40 to 50% lower than that of conventional bearings. Achieving low torque in bearings is also about lubrication, and in particular greases. In addition, using grease lubrication per se is an important issue. Grease is used widely for the lubrication of rolling bearings and ballscrews, and it can contaminate the soil, rivers, or sea if it leaks or is disposed of improperly. This could inflict considerable harm on the natural environment. Grease, of course is retained within bearings by seals and shields, and these units also play a role in energy conservation: a seal or shield that is too tight a fit will lead to friction in a bearing and consequent energy loss. The challenge in the bearing market has been to develop high- speed seals, which minimise bearing friction. This has led to the development of V type seal. The V seal is a design innovation that seals effectively without an increase in torque or operating temperature. It has better sealing capability than a shield, and a speed capability comparable to that of a shielded bearing. The non-contact lip of the V design reduces drag in the bearing - an important advantage where power loss is critical, as in small electrical motors. | ||||||||||
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