High Quality Slewing Ring Bearing

High Quality Slewing Ring Bearing

1.Reasons and solutions for the inflexible rotation and sound vibration of the slewing ring bearing:

Since the general large slewing ring bearing installation equipment and site do not have the ability to deal with complex faults, once the large bearing is not smooth, inflexible, or even has a dead point in a certain area, it is usually at a loss, and there are other large bearings. When the bearing rotates, it is accompanied by sharp noises and even swings and vibrates, which makes the equipment manager or operator panic all day long.

Generally speaking, as long as the large bearing can operate normally, a little noise and vibration are not enough to affect safe production, but it must be time to replace the large bearing, because at this time there must be losses inside the large bearing, either rolling elements or The cage, and the most likely is the fatigue shedding of the raceway hardness layer.

The second is that the eccentric load can be changed at the equipment site. For example, adjust the eccentric load on site, such as bucket turbine bearings, stacker-reclaimer bearings and ladle large bearings. Generally, it is equipped with eccentric load, and adjusting the eccentric load is the most reliable and safest method. Then quickly confirm the drawings and prepare for the production of new bearings.

The third is to fully add grease. It is necessary to fully understand that you must try to add grease. If necessary, even if the outer sealing strip is removed, clean it with kerosene from the surrounding direction and then add thin grease. You must know that only grease lubricated inside will minimize the internal frictional resistance.

Fourth, the obstacles that interfere with the operation of the large slewing ring bearing must be removed, such as the falling protective cover, the dust baffle, and the foreign matter interfering with the rotation of the gear. Often the noise of the large bearing comes from outside interference to a large extent.

Fifth, the new bearing is stuck or unable to rotate after installation, mostly because the contact point of the bearing channel is not good, the rotation is elliptical or the rolling element tolerance is inconsistent, which causes the rotation to be blocked. A factory reset should be initiated immediately.

2.How to deal with the abnormal sound after the new slewing bearing is installed?

Under normal circumstances, the slewing ring bearing has undergone a rotation test before leaving the factory. After installation, there is no external interference. If the new bearing is installed with abnormal noise, it can be handled and eliminated in the following ways.

1. Refill the thin grease from the lubricating hole and add it from the symmetrical grease nipple. During the filling process, rotate the bearing and rotate it from the positive and negative directions for several weeks.

2. Rotate the bearing to 360 degrees before trying to get the grease out of the seal or the oil discharge hole.

3. If there is no accident, the abnormal sound of the new bearing will disappear within one month to three months.

4. If it is a negative clearance bearing or a zero clearance bearing, check the rotation accuracy again.

5. For the three-row ball bearing and the cross-roller structure bearing, if the grease is fully filled, the abnormal noise will disappear quickly.

6. Especially for large bearings, installation and debugging, the levelness of the base, and the eccentric load will affect the bearing more or less, and should be carefully adjusted.

3.Regarding the influence of clearance on the rotation accuracy and life of the slewing bearing, this paper takes the four-point contact ball bearing as an example, from the core index of the influence of the clearance value on the slewing bearing.

First of all, the clearance value is divided according to the accuracy grade of the bearing, which is P0/P6/P5/P4 in order, so that the clearance is 0 and the clearance is negative.

It can be said that the size of the clearance value determines the machining accuracy and difficulty of the slewing ring bearing, and it affects the machining accuracy of other parameters.

The clearance above 0 does not actually affect the rotation performance. If it involves positioning, measurement and control and repeated positioning, even if it stops immediately, a negative clearance is necessary.

If it is required for rotation, the size of the clearance value cannot determine the life and reliability of the bearing.

To put it bluntly, the clearance value is artificially divided into several steps one by one according to the size and diameter of the bearing, from P0-P4, the range is reduced in turn. The actual required clearance value is determined according to the specific requirements of the working conditions.

In fact, the accuracy level of the bearing should be more suitable for its requirements. For example, the clearance value can be narrowed, or it can be set to 0 clearance and small clearance. Wait.

The working condition is the only indicator that determines the bearing clearance. It cannot be done step by step, and the various parameter values ​​of the bearing grade can be applied mechanically.

4.The warning signs of bearing wear or failure

Some of the premature failures experienced by slewing ring bearings can be prevented through careful monitoring of symptoms. One of the most basic indicators of slewing ring bearing problems is the condition of the lubricant. If metal particles or flakes are apparent, some form of wear is taking place.

Grinding, popping, or clicking noises from the bearing typically mean there is inadequate lubrication and/or excessive wear in the raceway.

Excessive play or movement signifies that the raceways are worn. As clearance increases, wear is usually accelerated, making close monitoring critical. The play, or clearance, in a slewing ring bearing is another important indicator of a problem. A new bearing is assembled with a specific amount of clearance to compensate for slight out-of-flatness encountered in a mounting structure. This clearance can increase dramatically due to wear.

An increase in torque or binding can mean that there is uneven wear in the raceway. If the turning torque of the bearing increases substantially or if the bearing has tight spots, this usually indicates an uneven load distribution.

With excavators, for example, the operator may notice a wobbling or rocking motion in the upper structure, especially when the digging arm is extended with a load. The operator may also sense a resistance to swing and find that the upper swings an inch or two past the point where it should have come to a stop. In advanced stages of wear, the bearing will pop and crack as the machine digs and wings.

By watching for symptoms of wear or failure, you can increase the life of the bearing and, when it becomes worn, have it remanufactured. Find out more about bearing remanufacturing and how it can save you time and cost compared to a new replacement bearing.