Installation of bearing during operation
On the contrary, in back-to-back installation, bearing the axial expansion of the inner ring spacer tends to reduce the bearing preload rather than increase the preload.
Installed back-to-back in pairs, the two bearings in the middle are installed face-to-face. As mentioned above, during operation, the temperature difference causes the preload of these inner bearings to increase. This installation method is not recommended.
When the shaft temperature is higher than the bearing pedestal, excessive axial load is generated on the two outer bearings. The two inner bearings have no load, resulting in a vicious cycle of increasing temperature rise, increasing preload and damaging lubricant, which is also an unacceptable installation arrangement and is also not recommended.
The axial expansion of such installed shaft and inner ring spacer does not increase the axial load or bearing preload.
Therefore, in order to prevent the increase of preload caused by thermal expansion, the bearing for the machine tool spindle is best installed back-to-back. When two pairs of bearings are used, each pair shall be installed in series, but the arrangement is back-to-back, as shown in Figure 91.
Since most of the main contacts in my work are micro and small ball bearings, the main contents of this paper are related to bearings. The applicable outer diameter is basically less than 22mm, and other types of bearings may have some differences.
definition
Ball bearing: it is a machined part composed of outer ring, inner ring, rolling element, rolling element holder, seal (dust cover) and spring ring.
Micro and small ball bearings with an outer diameter of less than 30mm are precision parts assembled at the bearing part to ensure the stable operation of the transmission shaft of rotating equipment with high precision requirements.
