NSK?s innovative designs begin with market-leading materials and unique heat treatment technologies that it develops in-house to produce both ball and roller bearings.
Mark Davies, NSK Australia?s mining manager, says that ?one of the key factors in the enhanced performance of NSK bearings is the development of industry-leading materials technology, in particular NSK?s Tough Steel range?.
Bearings made from the varying grades of Tough Steel are designed to out-perform normal bearings in contaminated, high temperature or inadequate lubrication conditions. Surface-orientated fatigue and material wear from contaminated lubricant is a common failure in the mining industry. As a key benefit of using NSK?s Tough Steel, the fine particle wear resistance of the Tough Steel increases operational life substantially.
As the Tough Steel technology can be used in any bearing design, NSK can tailor a solution to common modes of failure for many mining applications, providing a countermeasure to the operating conditions that are causing the reduced operating life.
NSK has developed varying grades of Tough Steel for heavy industries which is in common use throughout the world today, in applications such as slurry pump barrels, vibrating screen mechanisms and dragline gearboxes.
In addition to Tough Steel, another NSK development in standard material bearings is the High Performance Series (HPS). HPS, originally developed in small to medium size spherical roller bearings (SRB), has now been extended to the brass caged CA series large SRB and Vibration Spec SRB. Mark says it is expected that the new series of HPS bearings ?will give users benefits such as reducing their maintenance cost, downsizing their product design and saving energy?.
?It exceeds the limits of conventional bearings in terms of a longer operating life and limiting speeds, helping to deliver the high levels of reliability required in mining projects,? he explains.
Developed for applications with heavy or shock loads ? of the type encountered in jaw and cone crushers ? NSK?s CA series of double-row SRBs are manufactured with a machined brass cage to combat the effects of vibration, operating fatigue, wear and corrosion.
NSK has extended the HPS range into harsh vibrating applications with its CAM-VS series of SRBs. The CAM-VS series have been optimised for use in harsh vibrating applications. Their HPS vibratory specification builds upon the extended load and life benefits of the standard CA construction with an optimised design that provides improved fatigue strength against the vibration and shock-load conditions encountered on screens and feeders.
Mark says with increased speed limits up to 20 per cent higher than standard bearings, bore dimensions between 50mm and 240mm and operating conditions up to 2000C, NSK?s HPS CA series bearings ?are designed for the tough vibrating applications in the mining, quarrying and construction industries?.
Extra capacity cylindrical roller bearings (CRB) provide benefits in extending operating life and speed rating. NSK?s EW/EM series of cylindrical roller bearings lead the market in innovative design. The EW series features a pressed steel cage and the EM series a one-piece machined brass cage. These bearings are used in electric motors, gearboxes, dump trucks and other mobile fleet.
Both of these cage designs offer high load ratings for standard size bearings, in addition to a longer operating life (approximately twice that of a conventional CRB).
Also benefiting from NSK?s focus on improving bearing life in mining and extraction applications is a range of full-complement CRBs for use in crane sheeves. These bearings offer advanced levels of ingress protection with a sealing system that minimises grease leakage and increases resistance to the entry of water and other foreign substances. Designed to provide maximum reliability and operating life in the difficult environments encountered in mines and quarries, the bearings are supplied with phosphate surface treatment to improve their resistance to corrosion.