Because of the particularity of the structure and the diversity of the field situation, the slewing bearing of the excavator is prone to malfunction caused by the leakage of the rotary bearing, the rotary gear ring or the rotary motor, so the leakage should be prevented and treated promptly.
Structure and lubrication principle of slewing bearing
In fact, the oil lubrication of the rotary part of the excavator is divided into two cavities: the lubrication cavity of slewing bearing and the lubrication cavity of the rotary gear ring.
The lubrication of the slewing bearing is accomplished by adding lubricating grease to the lubricating oil nozzle in the outer ring of the slewing bearing, and the lubrication of the rotary gear ring is done by the grease in advance. Slewing bearings have both inside and outside (or the upper and lower) rubber strips as oil seals, external oil seals fixed in the lower frame of the slewing bearing inner ring (fixed plate), used to prevent the outside dust debris into the slewing bearing. The inner oil Seal is located on the outer ring of the bearing (moving plate) to prevent the grease in the Rotary gear circle from entering the bearing. Rotary gear rings and slewing bearings Use the same brand of Grease. The rotary oil seal is gradually thinned by the thickness, and finally forms a sharp angle, and only the elasticity of the rubber itself is controlled by the deformation of the protruding angle part by the rubber, and the sealing effect of the rotary bearing is achieved. This kind of seal to prevent oil spill a little effect, but the pressure is not high, once the internal due to too much refueling or the work temperature to increase the pressure, the grease will still leak through the oil seals. In normal circumstances, the leakage is related to the amount of filling, the working speed and frequency of the rotary part, and the temperature in the field. Therefore, there exists the ambiguity between normal and abnormal leakage.