Theoretical service life
Theoretical service life is a familiar concept in slewing ring technology. Due to the large number of influencing factors, not all slewing bearings will certainly reach their theoretical service life, but most of them will exceed, and some even exceed several times. The standard of theoretical service life cannot be directly applied to large slewing bearings, especially those that perform a rotary or slow rotational motion.
In most applications, the circumferential speed in the circumference of the revolution is relatively small so as not to interfere with operational stability and accuracy due to wear or scattered pitting. Therefore, it is not common to determine the size of a large slewing ring according to the theoretical service life for the slewing motion and the slow rotation motion. At this time, the concept of “lifetime” is adopted. When the rotational resistance is gradually increased, or the wear is continued, and the slewing bearing function can no longer be carried out, it indicates that the service life of the large slewing bearing has been reached.
Large slewing bearings are used for different operating conditions. Depending on the operating mode, such as different swivel angles and different frequencies of swivel motion, continuous swivel motion or continuous rotation, in addition to the choice of static force, the expected service life should also be considered from the perspective of dynamic stress.
The service life determined by means of the curve can only be used for slewing bearings that perform swiveling and slow rotary motion. Examples where this method is not applicable include
In these cases, Fenghe is based on the load spectrum (including the ratio of the corresponding speed and the on-time). At this time, it is necessary to clearly distinguish between the operating hours of the equipment and the actual rotation or turning time. Different loads are considered in the load spectrum and rate.