NSK Develops Spherical Roller Bearings Featuring High Reliability and Excellent Sealing Performance for Conveyor Pulleys in Mines

Product Equipped with the World's First Detachable Seal in a Spherical Roller Bearing* NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Toshihiro Uchiyama) today announced that it has developed highly reliable spherical roller bearings that feature an excellent sealing performance for use as bearings in conveyor pulleys in mines. The new bearings achieve greater bearing assembly precision and longer life by preventing foreign substance intrusion in harsh environments. NSK will contribute to higher productivity in mining operations with this new product, and it is targeting global sales of 1 billion yen in 2018. * According to investigation carried out by NSK. Development Background A shutdown of operations due to equipment failure or maintenance of mining conveyors, which can extend anywhere from a few kilometers to 20 kilometers long, has a big impact on productivity. That is why there is strong demand for highly reliable equipment that can run stably 24/7 under the harsh conditions of exposure to mine dust. Spherical roller bearings, which can absorb bending in the axis and possess high load capacity, are used in mine conveyor pulleys. There are two types of spherical roller bearings―sealed and without seals (open bearings). The development of early damage in bearings due to foreign substance intrusion has been an issue with the conventional open bearings. On the other hand, with sealed bearings, there have been problems securing seal space to ensure sufficient sealing performance and defective assemblies due to the inability to measure the bearing clearance when assembling the bearing into the equipment. With this in mind, NSK developed new spherical roller bearings that feature high reliability and excellent sealing performance. These new bearings achieve long life and excellent sealing performance in bearings that are the same size as the conventional product. They will enable accurate management of the proper clearance during bearing assembly and prevent the development of early damage due to foreign substance intrusion. Product Features 1. Perfect compatibility with conventional products The new bearings conform to ISO dimensions and can replace conventional products, since they are the same size. 2. Use of NSK's long-life materials technology Using proprietary material developed by NSK for the inner and outer rings and applying special heat treatment increases the load capacity and enables the inside of the bearings to be more compact. This makes it possible to secure seal space and achieve equivalent or better load capacity with the same size as the conventional products. 3. Use of NSK's sealing technology High sealing performance is achieved by using a seal with a long track record of preventing foreign substance intrusion. Moreover, using a bolt-fastened seal holder made it possible to remove the seal during assembly and measure the clearance. This enables the prevention of damage such as flaking and seizing due to incorrect clearance during installation. Product Benefits For use in mine conveyor pulleys used in harsh environments, this product will contribute to mining productivity with a service life that is four times longer than the conventional product.