Bearing News
20/09/2010
NSK develops Long-life, Spherical Roller Bearings for Vibrating Machinery
NSK has developed new long-life, spherical roller bearings for the use in vibrating machinery at mining facilities. The new, long-life bearings feature a service life more than twice as long as the current type and enable vibrating machinery to operate for long, continuous periods, while maintaining high reliability. NSK is targeting annual sales of one billion yen by 2011.
Development background
With the continuing global trend towards urbanization, global demand for natural resources continues to expand, especially among the BRICs (Brazil, Russia, India and China) and the developing countries. This has led, in recent years, to many mining facilities being operated 24 hours a day. Under extremely demanding conditions, facilities may be in operation more than 6,000 hours per year. Of the various vibration intensive facilities, the bearings employed in machinery used to separate ore and minerals at these mining facilities tend to have a shorter durable service life compared with other types of machinery. Any interruptions to the operation of this vibration intensive machinery can significantly impact mining production. Clearly, longer service life and higher reliability are crucial for bearings used in this type of machinery.
NSK’s new long-life, spherical roller bearings, developed using sophisticated analysis techniques, the latest advances in production technology and a program of stringent evaluation tests, are designed specifically for use in this vibration intensive machinery. The following advancements in product features are what make these bearings the answer to market demand for longer service life and higher reliability.
Product features
1. Proprietary NSK technologies deliver longer service life
The longer service life is made possible by the special surface created on the raceway of the outer ring, which is used to control the slippage action of the rollers. The curvature factor between the raceway and spherical roller has also been optimised. This reduces both slippage and the accompanying initiation stress between the roller and the contact surfaces of the outer and inner ring raceways. The result is a reduction in damage due to surface fatigue. These new advances in bearing technology are what give the new, long-life bearings a service life more than twice that of the current bearing type.
2. Leveraging a wealth of NSK’s proven specifications
NSK has succeeded in stabilising load distribution by controlling radial internal clearance and bearing dimensional tolerance factors. This was done by drawing on a wealth of design specifications accumulated through extensive experience working with some of the most demanding operating conditions around the world.
・Internal radial clearance is set at 2/3 that of ISO standard bearings.
・Bearing outer dimension tolerance in relation to bore dimension tolerance was set at 1/2 that of ISO standard bearings.
New Product Lineup
The new roller bearings, designed for use in a range of vibration machinery, come in 22 sizes. With outer diameters ranging from 90 mm to 400 mm, they are designed to help reduce the burden of maintenance at many different facilities in the mining industry.