Issue link: http://read.dmtmag.com/i/75471
TECHNOLOGY New generation of bearings An entirely new generation of higher performance spherical roller bearings has injected new life into bearing reliability and service along the conveyor line. A combination of improved bearing material, unique bearing design, and upgraded manu- facturing processes has helped to maximize the effect of lubrica- tion and minimize the effects of wear and contamination, while reducing friction. The result: A proprietary performance class of spherical roller bearings providing higher load-carrying capacity and extended bearing service life. These are well suited for the rigors of conveyor applica- tions in the aggregate industry due to an optimized design that benefits from refined internal geometry tolerances and improved surface structures. From the perspective of materials, the bearings are manufactured from high quality, clean, and homog- enous bearing steel that undergoes a unique heat-treatment process, increasing the bearing's wear resis- tance. The purity of the steel im- parts the bearings with strength and durability, and the specialized heat treatment creates a combination of hardness and dimensional stability. One key to improved perfor- mance is the redesigned internal ge- ometry. Using proprietary software, engineers analyzed the interrelationship of the bearing's rolling elements, raceways, and cage. Then, they devised methods to reduce friction, heat generation, and wear in the bearing, while increasing the ability to withstand heavier radial and/or axial loads. The bearing's rolling elements are manufactured to extremely close tolerances to reduce vibration levels and equalize load dis- tribution. Cages are enhanced to improve guiding of the rolling elements and optimize the effect of the lubricant while lowering heat, friction, noise, and vibration levels. The surface topogra- phy of the bearing's rolling elements and raceways enhances the formation of a hydrodynamic lubricant film, maximizing the ef- fects of the lubricant, while reducing heat generation and wear. Ultimately, they minimize environmental impact by reducing lubricant and energy consumption. Both during testing and in real-world applications, these bearings have been shown to run cooler, smoother, and longer than standard rolling bearings, particularly in heavy load slow- rotation applications, such as bulk conveyors. Triple protection barrier One of the technology developments engineered for conveyors — a three barrier solution — has introduced an environmen- tally friendly and cost-effective bundle of technologies to extend bearing service life and help prevent premature bearing failures without resorting to complicated auxiliary taconite seals and/or large quantities of grease. reliability along the conveyor line. A new generation of roller bearings has increased This proprietary solution consists of the following interre- lated components: Factory-sealed, high-performance spherical roller bearings (the newest generation) pre-packed with spe- cially formulated grease inside the bearing; optimized split pillow block housings with positive TLC-type external seals; and a recommended grease in the housing. The bearing is lubricated, sealed, and mounted inside the hous- ing, which is sealed and internally greased. This effectively delivers three layers of protection for the bearing during assembly and opera- tion: The integral bearing seals keep the lubricant in and contaminants out of the bearing cavity; the TLC seals in the housing protect against extremely fine contaminants and eliminate any need for expensive taconite seals; and the grease packed into the housing (at installation) on both sides of the sealed bearing completes the protection. The double-lip sheet-steel-reinforced seal is manufactured either from nitrile rubber or hydrogenated nitrile rubber and specifically engineered to prevent contaminants from entering the bearing's critical rolling contact area. Depending on oper- ating and ambient conditions, up to 90-percent reduction in grease consumption can be realized using these sealed bearings as part of the three-barrier solution. This can be attributed to the small quantity of grease required to lubricate a sealed spheri- cal bearing inside the sealed housing, compared with relatively large amounts of grease necessary to purge contamination from an open, unsealed bearing. AGGREGATES MANAGER DIGITAL EXCLUSIVE August 2012 41B