plaquette MACHLINE - Ntn-snr.com
plaquette MACHLINE - Ntn-snr.com
plaquette MACHLINE - Ntn-snr.com
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Spindle design:<br />
simplified calculation method<br />
Bearing pre-design<br />
This must be checked and optimized either by using<br />
the simplified and/or corrected calculation method<br />
with the bearing service life method, or by using an<br />
application-specific software design package.<br />
Required service life<br />
The bearing service life on a spindle is linked to the<br />
loss of machining precision (dimensional precision,<br />
vibrations) or to abnormal heating.<br />
This loss of precision is due to deterioration of raceway<br />
surfaces and balls due to wear, contamination,<br />
oxidation or lubricant deterioration (oil or grease).<br />
The corresponding service life cannot be directly<br />
calculated. The only possible calculation is for<br />
service life L 10 linked to material fatigue. Experience<br />
has shown that to give suitable spindle dimensions,<br />
service life L 10 should be of the order of 20,000<br />
hours.<br />
Simplified calculation method<br />
This most simple method, re<strong>com</strong>mended by the ISO<br />
281 standard is used to calculate the nominal<br />
service life reached by 90 % of bearings working<br />
under a dynamic load.<br />
The simplified calculation method shown opposite<br />
is based on material fatigue as cause of failure.<br />
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