How to solve the overheating of crane bearings?

Crane bearings need constant rotation and friction under working conditions, and heat will be generated continuously during the friction process. Generally speaking, there are roughly the following reasons for bearing overheating.

1 Poor lubrication

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

The factors that usually cause poor lubrication of bearings are:

Lack of lubricating oil (grease)

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

There is a problem with the quality of lubricating oil (grease)

Lubricating oil (grease) not added on time

Lubricating oil (grease) contains impurities

2 bearing wear

As an important part, bearings are used in various large and small machines, and some machines work in the open air, and when there is a lot of dust, some fine dust is easy to enter the high-speed bearing housing, causing the lubricating oil or grease in the bearing housing to deteriorate , poor operation, and then wear the bearings.

Bearings continue to run in a worn state, and due to increased friction, heat increases, resulting in an increase in bearing temperature.

3 Improper installation

Improper installation is another important cause of bearing heating. Because whether the bearing is installed correctly or not has a direct impact on its life and the accuracy of the main engine, it is required that the centerline of the shaft and the bearing hole must coincide during installation.

If the bearing is installed incorrectly, the precision is low, and the bearing has deflection, torque will be generated when it rotates, causing the bearing to heat up or wear. In addition, the bearing will vibrate, the noise will increase, and the temperature rise will also increase.

4 Insufficient cooling

Insufficient cooling usually manifests as: pipeline blockage, improper cooler selection, poor cooling effect, etc.

The cooler of the lubricating pipeline is fouled and blocked, which will lead to poor cooling effect, especially in summer production.

Severe fouling of the cooler and frequent alarms of high bearing temperature are encountered in many production sites. The more effective solution is to pickle and descale the cooler every year before summer.

5 big vibration

For example, poor coupling technology does not meet the requirements, the rotor has dynamic and static imbalances, poor foundation rigidity, weak feet, rotational stall and surge.

Some rotors are corroded by the medium or worn by solid impurities during operation, or the shaft is bent, which will cause unbalanced centrifugal force, which will cause the bearing to heat up, vibrate, and the raceway will be severely worn until it is destroyed.

6 Check and replace not in time

If the bearings are found to have severe fatigue peeling, oxidative corrosion, worn pits, cracks, or excessive noise that cannot be adjusted, if the replacement is not timely, it will cause the bearing to generate heat, abnormal sound, vibration, etc., which will affect the normal operation. Production.

In addition, the vibration caused by improper disassembly of the bearing and loosening of the anchor bolts of the equipment will also cause indentations on the bearing raceway and rolling elements, and cracks on the inner and outer races of the bearing. During the operation of the bearing, it should be inspected according to the specified cycle.

7 poor bearing quality

Rolling bearing parts work under high alternating contact stress for a long time in the form of point contact or line contact. The accuracy, service life and reliability of the main engine are largely determined by the bearings, so we must pay attention to the inspection during the purchase and acceptance of the bearings, and use qualified and high-quality products from regular manufacturers.

8 Improper selection of bearings

When selecting a bearing, attention should be paid to the limit speed and load capacity of the bearing, and it should not be used with excessive speed or overload, which will only shorten the service life of the bearing, and the gain outweighs the gain.

For the problems currently faced by the overhead crane you are using, you can consider the following aspects to solve them

1 Improper amount of refueling, too much or too little lubricating grease

The bearing housing should be oiled regularly according to the requirements of the work. After the bearing is refueled, sometimes the temperature is high, mainly because of too much refueling.

At this time, the phenomenon is that the temperature continues to rise, and after reaching a certain point (generally about 10°C~15°C higher than the normal operating temperature), it will remain unchanged, and then gradually decrease.

2 When the added grease does not meet the requirements or is polluted

If the lubricating grease is not selected properly, it is difficult to form a uniform lubricating oil film, which cannot reduce the internal friction and wear of the bearing, insufficient lubrication, and the temperature of the bearing will rise.

When different types of grease are mixed, a chemical reaction may occur, causing the grease to deteriorate, agglomerate, and reduce the lubricating effect.

Contaminated grease will also increase the temperature of the bearing. Dust will fall into the grease during the process of adding grease, causing grease pollution, causing the grease inside the bearing box to deteriorate, destroying the bearing lubrication, and increasing the temperature.

Therefore, appropriate grease should be selected. During maintenance, the bearing box and bearing should be cleaned, and the refueling pipeline should be checked and cleared. Different types of grease are not allowed to be mixed; if other types of grease are replaced, the original grease should be cleaned first; during operation and maintenance Add grease regularly, and the grease should be kept properly for moisture-proof and dust-proof measures.

3 When the cooling is insufficient

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

If the cooler is not selected properly, the cooling effect is poor, and it cannot meet the requirements of use, it should be replaced in time or a new cooler should be installed side by side. The axial flow induced draft fan should also check the heat preservation and sealing of the core cylinder.