The Right Bearing Makes a Big Difference

The Right Bearing Makes a Big Difference SKF, leading knowledge and engineering company, highlights some reasons why the right bearing choice for diverse industrial applications can result in increased performance and efficiency, while significantly reducing downtime and maintenance costs. Virtually every rotating element in industrial machinery relies on one or more bearings for effective operation. However, bearings are not, as is commonly believed, a "one-size-fits-all" product. A wide variety of specially designed bearing units are available, offering a number of benefits to engineers i.e. increased performance of machinery and service life, reduction of downtime and maintenance costs. To specify a bearing arrangement correctly for any application, it is necessary not only to select a suitable bearing type and size, but also to consider a number of other factors. These include the design and suitability of associated components such as the shaft and housing, the magnitude and direction of applied loads to the bearing, whether radial, axial or a combination of both, which holding devices are to be used, and whether the seals are adequate for resisting ingress of contamination from the bearing's operating environment. It is also important to consider the type and quality of lubricant, the precision and speed requirements of the bearing, and how easily it can be installed and removed for maintenance purposes. Each decision affects the performance, reliability and economy of the bearing arrangement and ultimately, the machine in which it is to be used. Each bearing type displays characteristic properties, based on its design, which makes it more appropriate for certain applications. For example, deep groove ball bearings, such as SKF's Explorer bearings, can accommodate radial loads as well as axial loads. They offer a combination of benefits ideally suited to applications such as small and medium-sized electric motors and centrifugal pumps. Depending on application requirements, SKF Explorer deep groove ball bearings are available with either metal or polyamide cages, as well as with or without seals or shields. The sealed versions use integral nitrile rubber or synthetic seals to protect the bearing from contaminants and retain the lubricant. The range of greases used are typically formulated with anti-corrosion additives and designed to withstand a wide range of operating temperatures. In higher load applications where space is limited, taper roller bearings are available with tapered inner and outer ring raceways with tapered rollers arranged between the raceways. The unique design makes these roller bearings particularly suitable for use in equipment with combined, radial and axial loads. The increased dynamic load carrying capacity of the taper roller bearing makes it possible to either reduce the size of the bearing units or to increase the strength and performance of existing assemblies. In other words, identical performance can be achieved with a more compact design but with improved power density. Smaller bearings also offer reduced friction, lower operating temperatures, noise and vibration levels. Spherical roller and CARB toroidal roller bearings are ideal for heavy engineering applications where heavy loads, shaft deflections and misalignments are common. SKF's spherical plain bearings, with integral triple lip seal and PTFE fabric liner, give maintenance-free operation over extended operating lives and provide long service life with minimal maintenance for heavy industry equipment. The bearings offer superior resistance to wear, higher load carrying capacity, higher bearing stiffness and lower frictional characteristics when compared to regular plain bearings, making them ideally suited to high load applications with slow rotational speeds. It should also be noted that specifying the correct type of seal is crucial. Bearings and seals are considered to be a complete system, with different seals available in many designs and in different materials to complement various bearing designs. Many factors influence the choice of an appropriate seal such as - the type of lubrication, the sliding velocity at the counterface, whether the seal will be mounted vertically or horizontally, shaft misalignment, and operating temperature. Research conducted by SKF shows that up to 14% of all premature bearing failures can be directly attributed to contaminants entering bearings via poorly designed or incorrectly specified seals, or because the materials used were unsuitable for a specific application - further proof that it is crucial to specify the correct seal type. With a multitude of different designs, incorporating customised rolling elements, housings, lubricants and seals, available for use with specific applications, it is clear that bearings can no longer be regarded as commodity products. It is also extremely important to choose the correct bearing for each application, as the performance, reliability and operating life of all production equipment is directly dependent on these vital components.