NSK's assest improvement program (AIP) has saved a manufacturer of concrete floors over $100,000 per annum on its maintenance budget.
The manufacturer of concrete floors for car parks and buildings has adopted a technolgy solution to the problem of recurring bearing failures on the manufacturing cassettes used to produce concrete floor sections.
NSK, together with its distribution partner, Wyko (UK) was called into the Chichester-based company following a spate of failures on the wheel hub bearings of the manufacturing cassettes. The bearings, two single row taper roller bearings adjusted against each other in the wheel hub, were failing an average 20-times a year. These failures were causing lost productivity and considerable concern to management, so a solution was required - rapidly.
Engineers from NSK's AIP program examined the wheel hub and found it's design to be the major problem; the outer rings of the taper roller bearings were not axially located, resulting in excessive clearance between the bearings, and, finally, bearing failure as the inner rings fractured. In addition, the sealing system on the bearing assembly was inadequate, allowing ingress of contaminants into the bearings, which were also contributing to the regular failures.
The design of the wheel hubs meant a straightforward substitution of one bearing type for another was not an option. Instead, NSK redesigned the hub and stub assembly to accommodate a more robust bearing arrangement using crane sheave bearings.
As the name applies, crane sheave bearings are usually employed in crane sheaves, in quarries, ports and building sites. However, the high load capacity and advanced levels of sealing provided by these bearings means that they are also ideal for use in wheels of mobile gantries and wagons used for quarries.
"We knew from our experience of the quarrying industry that crane sheave bearings would deliver the optimum solution in this application," said NSK's Richard McAulay.
They are essentially full complement cylindrical roller bearings offering an advanced sealing system that minimises grease leakage and increases resistance to the entry of water and other foreign substances. Their ability to provide reliable life in arduous environments is enhanced by machined holes, which are provided on the inner and outer rings of the bearings to allow grease replenishment, even while the bearing is in place. In addition, the bearings are supplied with phosphate surface treatment to improve their resistance to corrosion.
NSK's solution was validated in subsequent tests, with the result that the crane sheave bearings are now employed on all wheel hubs of the cassettes. The benefits of this are threefold.
- Actual savings of over $100,000 on the company's maintenance budget for bearings.
- The reduced maintenance works required for the application, as a result of easier installation, means decreased maintenance intervals requiring reduced man/hours per year.
- Productivity is improved as a result of an increase in speed of the manufacturing machine main spindle.
"This is a prime example of NSK knowledge applied to the customer environment," commented Richard McAulay. "No 'one size fits all' solution would have suited: it was only because we have people prepared to understand the end user, his environment, and what is happening to his product and his application, that we were able to acquire customer specific knowledge and provide a tailored solution."
NSK's AIP program is designed for end-user bearing customers that are looking for more than just product supply. Rather they are looking for a value-added service that actually helps them to reduce operating costs, improve efficiency and profitability. These objectives are achieved by delivering tangible savings to assets, such as equipment and machinery, and also by improving the working knowledge of maintenance and engineering personnel.