FAG super precision bearing speed, stiffness and deformation

The rotational speed that any type of bearing arrangement can achieve depends on the proper cooperation between the components, balancing the overall energy. The number of bearings, their position, internal stresses (play or preload), external stresses, and lubrication and heat dissipation are all decisive factors. The attainable speeds given in the bearing table are reference values ​​that can be higher or lower, depending on the conditions described above. The limiting speed given in the FAG spindle bearing bearing table is the speed capability of a single bearing under elastic preload. Rigid preloaded bearings, bearing pairs or bearing sets cannot reach these speeds. The deceleration factor is shown in Figure 14. Cylindrical Roller Bearings For cylindrical roller bearings, the maximum speed is achieved by adjusting the radial clearance. Refer to Table 8 on page 210 for instructions on installation instructions.

 Deformation and stiffness The stiffness of the bearing set depends on the bearing arrangement and preload. In addition to bearing stiffness, the stiffness of the machine tool's overall system is more dependent on the stiffness of the shaft and housing. Axial stiffness ca Axial stiffness is the ratio of axial load to axial displacement. Ca = Fa/δaca = Axial stiffness [N/μm] Fa = Axial load [N] δa = Axial displacement [μm] Relieving force KaE If a bearing group experiences axial forces through the shaft, the bearing is loaded Deformation will occur. Bearings with opposite contact angles and load directions will be unloaded. The unloading force KaE is defined as the axial force that reduces the preload of the bearing set to the unloaded condition through the center of the bearing.

 The displacement of the spindle bearing bearing set is almost proportional to the bearing unloading force. The axial stiffness ca given in the bearing table applies to bearing sets that are back-to-back or face-to-face. The radial stiffness cr can be estimated from the axial stiffness. Cr ? 6 · ca where α = 15°cr · 2 · ca Here α = 25° exceeds the bearing set of two bearings and above, both the stiffness value and the bearing capacity increase. Figure 15 shows an approximation of axial stiffness and bearing capacity under axial load. The radial stiffness of a bearing assembly subjected to radial center loads can be estimated from Figure 16. For Series 2344.. of Double Direction Angular Contact Thrust Ball Bearings, the axial stiffness value ca given in the bearing table applies if the axial force applied by the bearing does not exceed 2.2% of the rated dynamic load of the bearing C.