Excavator Slewing Bearing Leakage Treatment

Excavator Slewing Bearings due to the specificity of its structure and the diversity of the scene, prone to oil leakage caused by Slewing Bearings, rotary gear or rotary motor damage, it should prevent and timely treatment of leakage. This article will introduce some of the maintenance from the actual summed up the processing methods.

1. Structure and lubrication principle of Slewing Bearing

In fact, the excavator rotary parts of the grease lubrication is divided into two chambers: Slewing Bearing lubrication chamber and rotary ring gear lubrication chamber.

Slewing Bearing lubrication is located in the Slewing Bearing outer ring lubricating grease mouth filling grease to complete, rotary ring gear lubrication is completed by the pre-added grease. Slewing Bearings are inside and outside (or up and down) two rubber strips as oil seal, outside the oil seal fixed in the lower frame of the Slewing Bearing inner ring (fixed plate), used to prevent the outside of the debris into the Slewing Bearings. The oil seal is located on the outer ring (moving plate) of the bearing to prevent the oil in the rotary ring gear from entering the bearing. Rotary gears and slewing bearings use the same brand of grease. The rotary oil seal is gradually thinned by the thickness, and finally a sharp angle is formed, and only the elasticity of the rubber itself is tightened by the deformation of the rubber by the deformation of the sharp corners. This seal has a slight effect on the prevention of grease leakage, but the pressure is not high, once the internal due to excessive fuel or working temperature caused by increased pressure, grease will leak through the oil seal. And under normal circumstances the amount of leakage and the amount of injection, the rotation part of the working speed and operating frequency, as well as on-site temperature and other factors. Therefore, there is ambiguity about the normal and non-normal leakage.

2. Slewing Bearing leakage inspection

Often, in the case of work outside the oil seal appears a small amount of oil leakage is normal. The so-called normal, refers to the outer seal through the rotary seal oil leakage and the amount of grease added to the Slewing Bearing roughly equal. However, when a large number of oil leakage on the excavator abnormal phenomenon, it must be checked. Due to the particularity of the rotary part of the lubrication structure, it is necessary to analyze whether there is indeed a leak and determine the problem where the problem can be solved. The specific inspection steps and methods are as follows:

(1) whether the maintenance is correct

Slewing Bearing chamber filling grease cycle should be between 150 ~ 250h (manufacturers recommend the maintenance cycle is 250h, but the actual work can be based on the work of the rotary part of the intensity and frequency of appropriate shortening). If the filling is too frequent, will lead to a large number of oil leakage.

(2) Whether the hydraulic oil or gear oil of the rotary motor is swung into the cavity of the rotary ring gear

If there is a leak in this situation, open the check ring of the ring gear grease, you will find that the grease has become thinner. This thinning is mixed with hydraulic oil or gear oil characteristics.

(3) the original filling of the oil selection is correct

Due to the original equipment may not be correct filling the oil, there will be Slewing Bearings or rotary ring gear temperature slightly higher grease on the thinning situation. If the dilute oil is driven by the rotary motor's active gear in the meshing process to the upper end of the ring gear, it will flow through the oil seal into the bearing chamber, and finally the oil from the outer oil drain dripping out.

(4) whether the oil seal is missing

Carefully check the oil seal along the rotation to determine whether the local, section of the leak or even the surrounding leakage. Check whether the entire rotary seal is missing.

(5) whether the oil seal is fixed

The outer oil seal should be fixed relative to the sealing groove of the lower frame. The key to the inspection is to observe the excavator during rotary motion. If the oil seal is also rotating while the equipment is rotating, it means that the existing oil seal has been loosened in the sealing groove and the oil seal must be replaced. This method has a certain risk, so pay attention to safety, but this is to check whether the rotary seal does play a role in sealing one of the important methods.

(6) within the oil seal is obvious damage

Open the rotary ring gear grease check cover, check the ring gear oil is a large number of oil reduction, whether the seal broken pieces of oil. If it is a significant reduction in oil, indicating that oil has been missed.