Posted to News on 25th Aug 2011, 16:36
Spacea SJ series bearings for high temperatures and vacuums
NSK's Spacea SJ series high-temperature bearings employ a solid MoS2 lubricant to provide outstanding levels of performance in normal atmospheric, high-temperature and vacuum environments at temperatures up to 400degC. Manufactured from stainless steel and employing a patented 'peapod' structure for the cage that provides excellent torque stability and long life, the SJ bearings are designed for use in kilns, kiln cars, steel plants, vacuum vapour deposition equipment and high-temperature conveying equipment.
The patented design of the SJ series bearings is claimed to offer more than six times the durability of conventional bearings with solid lubricant paste, and also outperforms other solid lubricants in high-temperature vacuum environments up to 10-8Pa: its solid spacer joints exhibit minimal outgassing, thereby easing pollution concerns.
NSK's SJ design integrates a special cage pocket containing a solid lubricant spacer joint positioned between two specially treated balls. This arrangement, resembling a peapod, overcomes the problems of high-temperature environments - as encountered in kilns, vacuum deposition equipment and heat treatment conveyors, with the added benefits of extended maintenance-free performance and an extended operating life.
Materials technology
The longer life performance of the SJ bearings is achieved via the steady supply of lubricant - a sintered molybdenum disulphide material - which is provided by the spacer joint. This ensures increased durability in high-temperature atmospheric conditions. Also key to the SJ bearings' exceptional performance is a materials specification that includes martensitic stainless steel for bearing inner and outer rings and balls (the latter can also be ceramic for added durability), and austenitic stainless steel for the special pressed cages used in the bearings. In addition, the bearings can be protected against the ingress of contaminants with shields manufactured from austenitic steel.
NSK says that the balls used in the SJ series are one element in a two-part synergy designed to ensure excellent torque stability over extended operating periods. They are coated with the same molybdenum disulphide material used for the spacer joints, which results in a symbiosis in which both balls and spacer combine to achieve torque stability exceeding that of conventional silver-coated bearings, even under demanding vacuum conditions.
The SJ bearings are part of NSK's Spacea series of bearings and lubricants that provides high performance and reliability under all types of demanding operating conditions: super-clean, vacuum, non-magnetic, corrosive, high/low temperature, nuclear and high speed.
Spacea series bearings meet a wide range of technical requirements, through various combinations of high-performance materials, surface finishes and specially developed lubricants, including solid types. Depending on the application, Spacea bearings can be manufactured from martensitic and austenitic stainless steels for corrosive environments, ceramics, or a combination of both. Hybrid Spacea types can have any combination of ceramic inner/outer rings or ball; however, the range also includes all ceramic bearings for use in highly corrosive and high-temperature environments.
Contact NSK for more information about Spacea SJ series high-temperature bearings or use the form on this page.
