Hi-TF spherical roller bearing with removable seal

A cross section of NSK’s long life spherical roller bearing with removable seal shows the inner ring, cage, rolling elements, outer ring, seal carrier and seal.

In all mines and quarries around the world, NSK bearings are increasingly being specified for various applications requiring ultimate toughness. NSK strives for optimum performance and uptime of machinery and equipment, with product development that overcomes the challenges of arduous loads, misalignment, contamination and marginal lubrication conditions.

Here is an example.

Problem: Frequent failure of bearings on conveyor pulleys

The life of open spherical roller bearings for head, tail, drive and tension pulleys on mine and quarry conveyors is relatively short, typically only a few months. These bearings are prone to contamination from hard particles (dirt, dust) and water entering the housing seals and entering open bearings. In the absence of a better solution, this costly replacement cycle prevailed for many years.

In Australia, NSK worked closely with a number of major mining companies to establish on-site trials in problematic conveyor pulley locations where the mean time between failures (MTBF) was as low as 6 months.

Solution: a global innovation

NSK has developed a bearing solution that virtually eliminates the contamination problem and dramatically extends bearing life, while being as easy to install as a conventional open bearing. Using the company’s rugged Hi-TF steel, NSK has designed a bearing with a removable seal that is dimensionally interchangeable with standard spherical roller bearings and requires no modification to shafts or housings. It incorporates a Heavy Duty Nitrile Removable Seal (HBNR) capable of operating up to 100°C that provides 30% better sealing performance than standard seals, thanks to advanced spring lip technology. The breakaway seal allows for conventional installation with access to clearance measurement during bearing drive-up and bearing packing with the end user’s grease preference.

Technical Endurance: Tough Steel

Engineered with advanced material properties and innovative heat treatment technology, NSK Tough Steel™ bearings offer significant performance advantages over conventional bearing steel:

  • Exponentially longer life under contaminated and marginal lubrication conditions
  • Up to four times the life at 160°C
  • Less than a third of the wear rate
  • Up to 40% improvement in resistance to seizures

Increased lifespan. From 6 months to 10 years

Some of the tested spherical roller bearings installed by NSK ten years ago are still in service and running smoothly. As further testimony, NSK removed a set of fully functional bearings after two years and performed an X-ray fatigue analysis. The result indicated that there was more than eight years of remaining life remaining. The NSK solution has demonstrated a reliable life of ten years – far longer than anything previously experienced in these applications.

Since then, NSK has supplied more than 1,600 long-life spherical roller bearings with removable seal technology to the nation’s mining industry. A full range of standard sizes from 120mm to 480mm bore diameter is now available worldwide.

About NSK

Globally, NSK is a recognized leader in advanced motion and control technologies, rapidly driving major developments in materials, mechanical design, lubrication and sealing to reduce bearing size, extend life Mean Between Failures (MTBF) and reduce costs without compromising machine performance. And NSK mining industry experts have worked on-site for decades, in the field with mine operators around the world. This accumulated expertise means we understand the multiple challenges they face and apply this knowledge to deliver highly technical, application-specific solutions that have a lasting and documented impact on mine productivity, efficiency and profitability.
Visit NSKAmericas.com to learn more.


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