Object damage is a very normal phenomenon, slewing bearing is no exception. In all kinds of construction machinery, such as automobiles, cranes, excavators, etc., slewing support is an important component that transmits axial load, radial load and tipping moment between the turntable and the chassis. However, in daily maintenance work, it is often found that the slewing support raceway has been seriously damaged, such as annular cracks along the raceway on both sides of the inner seat ring and the lower raceway in front of the operation area. Compression occurs in the large force area of the raceway on the outer seat ring, and occurs in the whole compression area. Today, Xiaobian will take you to analyze the causes of slewing bearing damage and effective countermeasures.

1. Reasons for damage of turntable bearing

1. Poor smoothness

According to the survey, poor flatness is one of the main reasons for premature bearing damage, accounting for about 50%.

The main reasons are: smooth agent or smooth oil injection is not timely; The smoothing agent or smoothing oil is not in place; Improper selection of brightener or smoothing oil type; The smooth way is not correct, etc.

Countermeasures: Choose the right smoothing agent or smoothing oil and use the right smooth filling method.

2, improper installation

① The device uses brute force, and the direct impact of the hammer on the slewing bearing has great damage to the bearing, which is the main cause of deformation.

② The device is not installed in place, the device has an error or is not installed to the bearing position, resulting in too small bearing clearance. The inner circle and the outer circle are not at the same center of rotation, forming different concentric centers.

Countermeasures: Appropriate or professional bearing device items should be selected, and special instruments should be used at the end of the device for testing.

3. Fatigue

Fatigue damage is a common way of bearing damage. The common causes of fatigue damage may be: bearing overload operation for a long time; Not timely maintenance; Improper maintenance; Equipment aging, etc.

4. Pollution

Pollution can also lead to premature damage to rotary bearings, pollution refers to dust, metal debris into the bearing.

Main reasons: open the packaging of slewing support too early before use, resulting in pollution; The working environment of the device is not clean, resulting in pollution; The working environment of the bearing is not clean, and the working medium is polluted.

Countermeasures: It is recommended not to disassemble the bearing packaging before use, keep the equipment environment clean when installing the device, clean the bearings to be used, and strengthen the sealing device of the bearings.

Second, methods and measures to prevent damage to slewing supports

1. Through finite element analysis, the plate thickness of the connecting part of the turntable and the slewing support is appropriately increased in order to improve the structural stiffness of the turntable.

2, the large diameter slewing bearing design, should be appropriate to increase the safety factor; An appropriate increase in the number of rollers can also improve the contact between rollers and raceways.

3, improve the manufacturing accuracy of the rotary bearing, focusing on the heat treatment process. It can reduce the intermediate frequency quenching speed, strive to obtain greater surface hardness and hardening depth, and prevent quenching cracks on the surface of the raceway.