New Roller Bearings Offer Extended Service Life

Engineering consumables supplier Bearing Man¡¯s bearings division has launched a new range of high-performance NSK spherical roller bearings, with a running life of nearly double that of conventional bearings of the same size. Other advantages of the newly-designed HPS range include reduced maintenance costs, energy savings and downsizing in product design. The maximum limiting running speed of these spherical roller bearings has also improved by 20%, the company states. ¡°During rotation of conventional spherical roller bearings, slip between the raceway and roller causes fatigue, which eventually leads to flaking,¡± says Bearing Man¡¯s Lionel Burden. ¡°To counter this, NSK has developed a special treatment on the surface of the outer ring that improves the traction of rollers and controls the rotational speed of these rollers. ¡°This advanced technology, which has extended the service life of these bearings by up to twice that of conventional spherical roller bearings, also increases the bearing dynamic load rating.¡± NSK also applies a special nitriding treatment to the surface of the cage, which forms a finer, harder and more uniform surface than on conventional bearings. Maximum limiting speed is significantly increased and cage wear in harsh operational applications is reduced. Robust HPS spherical roller bearings, which are available nationally from Bearing Man, have bore sizes of between 40 mm and 130 mm. These bearings offer extended service life, reduced maintenance and enhanced performance in diverse applications. The company also works closely with Vegter Condition Monitoring to offer profes- sional condition-monitoring and alignment services. ¡°By using the shock pulse method (SPM), which is a unique measuring technique for moni-toring rolling element bearings, more than just bearing damage can be detected,¡± says Bearing Man divisional director Paul Mckinlay. ¡°Lubrication problems, misalignment and cavitation trouble are easily recognised and this method helps to identify the causes of the damage so that units can be fixed before further destruction occurs.¡± There are various ways of implementing the SPM by using hand-held instruments, or by using continuous-monitoring systems. The SPM method is able to quickly scan pumps or other rotating equipment bearings and generate an alarm report. The latest SPM instruments, which provide a new capacity for analysing machines, are capable of carrying out full vibration analyses, in both frequency and time domains. These instruments also offer true simultaneous two-channel measuring, orbit analysis, run-up and coast-down, as well as bump-test functions, with the possibly of 40 kHz and 12 800 lines resolution. ISO vibration severity measurements, according to the latest ISO 10816 standard, are also possible, as are contact temperature, speed (belt and rotational), analogue measurements or recording of any other measurable entity. These instruments can even record shock pulse spectrum measurements to confirm specific bearing defects, as well as other shocks generated throughout a machine. Good control and coordination is critical for efficient condition monitoring. Important factors include adherence to time schedules for readings and careful control of the database. The correct decisions must be taken about which machines require further investigation. Vegter Condition Monitoring is the local representative for SPM Instrument AB, which developed the SPM over 40 years ago. In spite of attempts by other companies to imitate it, this system remains the fastest and most reliable technique available for measuring rolling element bearing operation and lubrication conditions.