NTN develops graphite lubricated sintered bearing for dry environments

February 27, 2013

February 27, 2013

NTN Corporation has announced further additions to its BEARPHITE range of sintered bearings. The company’s new ‘Self-Lubricating BEARPHITE’ bearings are designed to be used in environments unsuitable for traditional oil impregnated sintered bearings, using graphite as a ‘solid lubricant’.


Example of NTN’s new self lubricating bearing.

Inner diameter 6 mm × outer diameter 12 mm ×

width 6 mm

Traditional oil-impregnated sintered bearings, widely used in the industrial machinery and automotive fields, are lubricated with oil retained within the bearing. However, oil-impregnated sintered bearings cannot be used in certain applications where the lubricant may adhere to surrounding components and cause a reduction in performance, or hot environments where the lubricant is prone to evaporation, such as the inside of photocopiers or automobile headlights.

The graphite added as the solid lubricant for ordinary sintered bearings has a lower liquidity compared to other metal powders and, states the company, cannot be moulded properly in large quantities. NTN changed the ratio of metal powder and increased the quantity of ‘high-liquidity’ graphite to five-fold over conventional types of graphite. NTN state that this combination has resulted in a high level of productivity, while also delivering outstanding sliding characteristics and wear resistance without the need for lubricating oil.


Area ratio of graphite 80% (quantity of graphite additive five-fold compared to conventional products)

The developed bearing is also conductive which allows static electricity to be released while also preventing the adhesion of dust, one of the causes of non-conforming bearings. The bearing can also operate as a material for supplying electricity, which eliminates the need for other electricity supply components and contributes to a reduction in the number of components used in devices.

NTN has already begun offering the developed product to office equipment manufacturers and automotive related manufacturers. In addition to bearings, the technology can be applied to a wide range of fields, as it can be used in composite material products with integrated resin parts, or applied to sliding materials other than bearings.


Posted by: Paul Whittaker, Editor ipmd.net, [email protected]   

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February 27, 2013

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