Grease lubrication

Example 1

An SKF Explorer 6210 deep groove ball bearing is lubricated via an oil bath. The oil viscosity is 68 mm2/s at 40 °C (105 °F), load P = 0,24 C0. What is the adjusted reference speed?
The limiting speed for this bearing is 10 000 r/min, which is higher than its adjusted reference speed. In cases like this, the lower of the two rated speeds is the most significant for the service life of the bearing. In general, speeds up to the adjusted reference speed provide conditions favourable for extended bearing service life. Higher speeds up to the bearing limiting speed can, in principle, be adopted after further assessment of the specific temperature conditions surrounding the bearing arrangement.

Example 2

A grease lubricated SKF Explorer 22222 E spherical roller bearing is subjected to a load P = 0,15 C0. The grease has a base oil viscosity of 220 mm2/s at 40 °C (105 °F). What is the adjusted reference speed?
Up to this speed, the bearing thermal conditions are generally considered normal. Higher speeds, up to the limiting speed of 4 000 r/min, can also be considered under certain circumstances. This would require an assessment of the temperature rise of the application based on the actual frictional and cooling conditions within the application. In cases like this, the lubricant, heat dissipation, bearing internal clearance and accuracy of the bearing seats must be verified and adapted to accommodate higher speeds. For these types of evaluations, contact the SKF application engineering service.
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