Why your bearings always broken?

The high temperature of the bearing in the machine is a common and harmful fault of the rotating equipment. If not handled properly, the service life of the bearing will be reduced, the maintenance cost will be increased, and even the bearing will be burnt out, which will destroy the machine!

Therefore, the rapid judgment of the causes of the failure, to take appropriate measures to solve, is the continuous safe operation of equipment protection.

8 symptoms of bearing overheating

1. Poor Lubrication

Lubrication has an important influence on the service life, friction, wear and vibration of bearings. Good Lubrication is the necessary condition to ensure the normal operation of bearings. According to statistics, about 40% of the bearing damage are related to poor lubrication.

Common Causes of poor bearing lubrication are:

Lack of lubricating oil (grease)

The lubricating oil pipe is blocked by foreign matter, etc. 

The quality of the lubricating oil (grease) is in question

Failure to add lubricating oil (grease) on time

The lubricating oil (grease) contains impurities

Bearing wear

Bearing as an important part, used in a variety of large and small machines, and some machines in the open environment, and dust, some fine dust easy to enter the high-speed operation of the bearing seat, causes in the bearing housing the lubricating oil or the lubricating grease to deteriorate, the movement is not good, then causes the bearing to appear the wear.

Bearing in wear state to continue to run, as the increase in friction, heat increases, resulting in the bearing temperature.

Sand and gravel dust on the bearing damage

3 improper installation

Improper installation is another important reason for bearing heat. Because the bearing installation is correct or not, on its life and host accuracy has a direct impact, so the installation of shaft and bearing hole must coincide with the center line.

If the bearing installation is not correct, low precision, bearing deflection, rotation will produce Torque, causing bearing heat or wear. In addition, the bearing will also produce vibration, noise increases, will also increase the temperature.

4 undercooling

Insufficient cooling is usually manifested as: blocked pipes, improper selection of coolers, poor cooling effect and so on.

The cooling effect will be worse, especially in summer, if the cooler of lubricating pipeline is blocked by scaling.

The scale of the cooler is serious, and the high temperature of the bearing often gives an alarm. The effective way is to remove the scale of the cooler by pickling before summer.

5. Big Vibration

For example, the coupling alignment process does not meet the requirements, rotor dynamic, static imbalance, poor foundation stiffness, false ground, rotating stall and surge.

Some rotors in the process of operation due to corrosion by the medium or solid impurities wear, or bending shaft, it will lead to unbalanced centrifugal force, so that the bearing heat, vibration, raceway wear seriously, until destruction.

6 check the replacement is not timely

If serious fatigue spalling, oxidation corrosion, worn pits, cracks, or excessive noise can not be adjusted, if the bearing is not replaced in time, it will result in heating, abnormal sound, vibration, etc. Which can interfere with normal production.

In addition, the improper removal of bearings, equipment anchor bolts loose vibration, will also lead to bearing raceway and rolling body indentation, bearing inner and outer ring cracking. During the operation of the bearing, the inspection shall be carried out according to the specified period.

7 Poor bearing quality

Rolling bearing parts in the form of point contact or line contact, in the high alternating contact stress under long-term work. The accuracy, life and reliability of the main engine depend on the bearing to a great extent, so we must pay attention to the inspection in the bearing procurement acceptance link, using the regular manufacturers of qualified high-quality products.

8 improper bearing selection

Bearing selection should pay attention to the limit speed of the bearing, load capacity, can not overspeed, overload use, that will only shorten the service life of the bearing, not worth the loss.

A good way to cool a bearing

When the bearing temperature is high, should first solve the problem from the following aspects.

1 improper amount of oil, excessive or too little lubricating oil

The bearing box shall be lubricated regularly according to the requirements of the work. Bearing oil sometimes will occur after the high temperature, mainly too much oil.

The phenomenon is that the temperature is continuously rising, and it will remain constant at 10 °C ~ 15 °c higher than the normal operating temperature after reaching a certain point, then it will gradually decrease.

2 when the oil added does not meet the requirements or is contaminated

Grease selection is not appropriate, not easy to form a uniform lubrication film, can not reduce the internal friction and wear, lubrication, bearing temperature rise.

When different types of oils and fats are mixed, a chemical reaction may occur, resulting in the deterioration of oils and fats, caking, reducing the lubrication effect.

Oil pollution will also make the bearing temperature rise, grease into the dust, resulting in oil pollution, resulting in the bearing box internal grease deterioration damage bearing lubrication, temperature rise.

Therefore, the proper grease should be selected, the bearing box and bearing should be cleaned and the oil pipeline should be checked and dredged, and the grease of different models should not be mixed Regular operation and maintenance of grease, grease should be properly stored for moisture and dust prevention measures.

The bearing of motor is burned out due to insufficient lubricating grease

3. undercooling

Check whether the pipeline is blocked, the oil temperature and return water temperature is over the standard.

If the cooler selection is not appropriate, poor cooling effect, can not meet the use of requirements, should be timely replacement or parallel installation of new cooler. Axial-flow induced draft fan should also check the insulation and sealing of the central cylinder.

What should bearing inspection pay attention to

1. Bearing quality

First of all, check whether the lubricating grease has deterioration, caking, impurities and other undesirable conditions, which is an important basis for judging the cause of bearing damage.

Secondly, check whether the bearing is scuffed and worn, check the surface of the bearing's inner and Outer Ring, rolling body and cage, and check whether there are cracks, rust, peeling, pits, overheating and discoloration, etc. Check whether the Bush is wearing, pit point, peeling, if there is the above should be replaced with a new bearing.

2. Bearing fit

When the bearing is installed, the fit between the inner diameter and the shaft, the outer diameter and the Shell is very important.

Creep, once produced, will wear out the mating surface, damage the shaft or Shell, and wear powder will penetrate into the bearing, causing heating, vibration and damage.

When the interference is large, the outer diameter of the outer ring will become smaller or the inner diameter of the inner ring will become larger, reducing the internal clearance of the bearing.

In order to select suitable bearings, bearing load nature, size, temperature conditions, the inner ring and outer ring of the rotating conditions.

3 adjustment of bearing clearance

Bearing gap is too small, because the grease in the gap in the shear friction loss is too large, will also cause the bearing heat, at the same time, the gap is too small, the amount of oil will be reduced, too late to take away the heat generated by friction, will further increase the temperature rise.