Accuracy  

When preloaded, SoCare® Crossed Cylindrical Roller Slewing Bearings provide a high degree of stiffness, due to the large roller/raceway contact area. These Slewing Bearings, which have a high degree of running accuracy, are typically used when accurate positioning is a key operational parameter. Four-point Contact Ball Slewing Bearings have a lower degree of stiffness. 

Magnitude and Direction of Loads 

The magnitude of the load is one of the factors that usually determine the size of the Slew Ring to be used. Generally, Four-point Contact Ball Slewing Bearings are able to withstand heavy loads and shock loads. They can be adapted for slewing applications where heavy loads vary in magnitude and direction. Using the static limiting load diagram, together with the bearings listed in the product tables, the required bearing size can be estimated using the resulting axial bearing load and the magnitude of the tilting moment. 

Permissible Operating Temperature 

The permissible operating temperatures for Slewing Bearings listed in this catalogue are determined primarily by the spacer and seal material and the grease used for lubrication. The permissible operating temperature typically ranges from –25 to +70 °C. If Slewing Bearings are required to operate outside the reference temperatures, contact the SoCare® application engineering service. Also contact the SoCare ® application engineering service if the outer ring has a lower temperature in operation than the inner ring, which might lead to reduced internal clearance or increase the preload in the bearing. 

Vibration 

For applications subjected to vibrations, pre-loaded Four-point Contact Ball Slewing Bearings are typically used. However, Crossed Cylindrical Roller Slewing Bearings are also suitable. In cases where sufficient experience with a similar bearing arrangement is not available, it is strongly advised to consult the SoCare® application engineering service. 

Operating Speed 

SoCare® Four-point Contact Ball Slewing Bearings generate less friction than Crossed Cylindrical Roller Slewing Bearings. Consequently, Four-point Contact Ball Slewing Bearings also have a higher speed capability. These bearings can accommodate tangential operating speeds up to 4 m/s. Crossed Cylindrical Roller Bearings are limited to approximately 1,5 m/s for continuous slewing motion and up to 2 m/s for brief periods.

Sealing 

The selection of a seal is vital to the performance of a slewing bearing. The standard seals used in SoCare® Slewing Bearings provide good protection against moisture and contaminants and also provide reliable retention of the lubricant. These integral seals are not intended to protect bearings that operate under extreme conditions where, for example, they are exposed to water, vacuum, high levels of abrasive contaminants, or radiation. For these types of applications, additional external seals must be used to prevent media from entering the bearing cavity. 

*Reference: SKF on bearing selection