Bearings suit high-speed spindles

NSK's new BGR Series of super precision angular contact bearings combines the benefits of SHX heat and seizure resistant steel and ceramic balls, to meet the high accuracy (ISO Class 2) and high speed (up to 244,000rev/min) requirements of the internal grinding industry. The combination of special long life SHX steel and ceramic balls in the BGR design also ensures extra bearing life for users of grinding spindles. SHX steel is highly suited for use in machine tool spindles, which must run at high speeds with a minimum supply of lubricant Importantly, the heat resistance of SHX is nearly equal to that of M50 steel, a material which is used widely in bearings for jet engines, and its wear resistance, resistance to seizure and durability are all superior. Building on its special materials technology, the optimised BGR design integrates an outer ring guided cage for better lubrication and also has the shoulder of its inner ring relieved to ensure a stable supply of oil into the bearings. The net benefit of these measures is more reliable and efficient bearing operation under the demanding high speed, high temperature conditions encountered in internal grinding. Offering ultra high accuracy to ISO Class 2 (ABMA ABEC9) as standard, the BGR series bearings offer easy handling for the user as a result of their nonseparable inner ring. This feature makes spindle assembly easier, while allowing users to benefit from the ability to configure the BGR bearings in universal combinations of back-to-back (DB), single or tandem (DT), or face-to-face (DF) arrangements. BGR series bearings are available in ISO dimension series (10 and 19) and bore sizes from 6 to 25mm, and are offered with the choice of steel balls, ceramic balls or a combination of ceramic balls and SHX rings. The bearings are suitable for use with high-speed greases (up to 192,000rev/min with ceramic balls) and SHX material and oil-air lubrication systems, which, in combination with ceramic balls and SHX rings, enable the BGR series bearings to achieve their highest operating speeds: up to 244,000rev/min with a 6mm bore bearing. BGR series bearings with SHX rings are suitable for use in the repair and maintenance of internal grinding spindles, where they can provide an upgrade in terms of reliability. Full details of the BGR series bearings and NSK's other super precision range of bearing products are contained in a new global catalogue just produced by the company. The new publication covers what is probably the largest range of super precision bearings available from any one manufacturer. It runs to 210 pages and contains seven easy-to-use sections, plus a host of illustrations and tables dealing with everything from mounting to preload constants to lubrication types, and tolerances for shaft and housing bore diameters. The layout of the new catalogue is designed to support spindle designers by simplifying the task of finding product and application information.