October 27, 2005
NTN Develops Micro-High-Lubrication Tapered Roller Bearings
The NTN Corporation has developed micro-high-lubrication* tapered roller bearings that provide at least 5 times the service life under severe lubrication conditions.
NTN is developing high-lubrication bearings that provide longer service life in which the oil film parameter lambda** is greater than 0.5. With the viscosity of the oil used in automobile transmissions and differentials being steadily reduced, oil film parameter lambda is falling below 0.5 (VG10 oil used). In order to handle such increasingly severe lubrication conditions, NTN has developed micro-high-lubrication tapered roller bearings.
Micro-high-lubrication treatment forms finer dimples in the metal than conventional high-lubrication treatments and maintains surface roughness equal to ultra-finish. Thanks to the micro oil pot effect, adequate oil films can form even under the severe lubrication conditions of lambda 0.2 (VG1.5 oil used) to 0.5, conditions under which it is difficult for oil film to form. This process, therefore, maintains calculated service life by reducing lubrication limitations.
Micro-high-lubrication treated tapered roller bearings can also be combined with previously developed high-load capacity tapered roller bearings, which raises the number of rollers to the maximum, to achieve further increases in service life.
| * HL: | High Lubrication |
| ** Oil film parameter lambda: | |
| The ratio of the surface roughness to the oil film thickness expressed as follows: Lambda = Raceway surface minimum oil film thickness/composite surface roughness Composite surface roughness: σ=(σ12+σ22)1/2 [σ1:roller surface roughness, σ2:raceway surface roughness] |
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[Features]
- Lengthens the service life with clean oil lubrication conditions under which an oil film is difficult to form.
- 5 times or more the service life when lubricating with clean oil and oil film parameter lambda = 0.5 (when compared to standard bearings)
- 13 times or more the service life when lubricating with clean oil and oil film parameter lambda = 0.2 (when compared to standard bearings)
[Applications]
- Automobile transmissions and differentials
[Product Features]
[Means for realizing longer service life]
