Reasons and Solutions for Broken Teeth of Excavator Slewing Bearing

We all know that the excavator can turn left and right when it is working, and it is the slewing device that works. The slewing bearing is a crucial part of the slewing device, which is mainly used to support the weight of the car body and bear the working load. Because the slewing bearing of the excavator is generally operated with a large load, and the working environment is relatively harsh, the slewing bearing is prone to the failure of the slewing bearing broken teeth. Do you know the reason for the broken teeth of the excavator slewing?

Ⅰ. Reasons for broken teeth of excavator slewing bearing

Under normal circumstances, the broken teeth of the slewing bearing are mainly internal meshing and hard tooth surface, but the slewing bearing with external meshing and soft tooth surface rarely has the problem of broken teeth. Most of the broken teeth of the slewing bearing appear within one year of the early stage of the whole machine, and it is caused by radial oblique extrusion. The pinion meshing with the slewing gear is mainly driven by a floating shaft, and the slewing bearing itself has a certain gap. During the working process of the excavator, it is easy to generate a certain overturning moment, which leads to a certain inclination angle and radial displacement of the center line of the pinion, and the center distance of the gear transmission will change accordingly. not excluded. Under normal circumstances, the factory clearance of the slewing bearing used by the excavator is less than 0.2 mm. After a period of use, the clearance of the slewing bearing will become larger. In fact, in the working of the excavator, the raceway of the slewing bearing for excavator is generally somewhat deformed.

Ⅱ. Solutions to the broken teeth of the excavator slewing bearing

1. Ensure that the gap between the tooth sides of the meshing gears is not greater than 0.06 times the modulus

For a 20 t-level excavator, the appropriate module of the turntable slewing bearing is ten millimeters, and the backlash of the large gear and the pinion meshing is greater than or equal to 0.6 millimeters. In the excavator aftermarket parts market, customers generally do not pay much attention to the backlash between the large gear and the pinion, so the probability of broken teeth of the slewing bearing has always been very high. In response to this problem, the relevant staff should explain the relationship between broken teeth and backlash to customers, so that they understand that if the backlash is not well controlled, broken teeth of the slewing bearing will definitely occur.

2. Select the appropriate helical gear slewing bearing

Change the slewing ring gear from full tooth width to 37 degree chamfer. Please note that the changed ring gear of the slewing bearing is the tooth part of the non-installation surface, and then the part of the slewing bearing that often breaks is cut off, so that the extrusion force will not be concentrated on the upper half of the tooth width when the pinion is displaced. In this way, the tooth part of the slewing bearing of the excavator will not have extrusion cracks in the early stage of use, which can delay the time when the teeth of the slewing bearing are broken to a certain extent, and the service life of the excavator is prolonged. According to the statistics of relevant data, after adopting this type of slewing bearing in the aftermarket parts market of excavators, it is found that the broken tooth rate has decreased.

3. Adopt drum tooth slewing bearing

The drum tooth slewing bearing has great advantages in reducing extrusion. First of all, the angular displacement compensation of the drum gear slewing bearing is relatively large when the large gear and the pinion mesh, which greatly changes the contact conditions when the large and small gears mesh, and reduces the vibration caused by the gear pair during the transmission process. Greatly reduces the squeezing of the large and small gears. Secondly, under normal circumstances, due to the incorrect operation of the operator and the rigidity of the installation of the driving pinion arm, the large and small inner wheels often cause a large angular displacement during the meshing or rotation process. However, the drum tooth slewing bearing can avoid this situation, thereby reducing the extrusion force and avoiding the occurrence of broken teeth caused by stress concentration. According to relevant statistics, after adopting this type of slewing bearing, the aftermarket parts market for excavators has not received any feedback on the problem of broken teeth. The drum tooth slewing bearing has achieved good results in solving the broken tooth fault.

The above is a detailed explanation from professional slewing ring manufacturers of the cause analysis and solutions for the broken teeth of the excavator slew bearing. When the slewing bearing of the excavator has broken teeth, it must be stopped and replaced with a new slewing bearing to make it work normally again.