Why is the bearing of the running motor overheated?
In the production, the rolling bearing “fever” is often encountered. If the cause analysis is unclear, the treatment is not timely, and the measures are not proper, it will often be half the effort, and even cause a bad accident such as bearing burnout and gear reducer.
Let's talk about a few typical cases encountered during the production and debugging process, and analyze and summarize the specific problems in the design, installation, lubrication, assembly and other links for your reference.
Bearing fever caused by improper lubrication
1. There is a congenital deficiency in the design of bearing lubrication parts.
ZB's No. 1 kiln head surplus fan had many bearing burnout accidents in the year of 2003 (in the initial stage of production), and after on-site investigation, it was found that there was a problem with the oil mark design of the bearing housing.
When the oil level is engraved under the oil mark, the actual measurement, the lowest row of balls of the bearing has just touched the oil surface, and only when the oil level is displayed on the upper scale line can the operation be satisfied.
When the oil level is close to the lower engraving line, the lubrication condition deteriorates. At first, the bearing temperature rises slowly. The on-site personnel did not pay enough attention to the bearing fever alarm. Once the temperature rise reaches a certain level, it will rise sharply in a very short time. Burn out the bearing. Therefore, incorrect labeling of the oil mark will cause misleading to the inspection and maintenance personnel. After finding out the reasons, the refueling standard line was redefined.
Another example is the high-speed shaft bearing of CL company's rotary kiln reducer. After only 2~3 hours of starting, the bearing suddenly smokes. The reason for the accident analysis was that the oil return hole in the high-speed shaft bearing housing was too low, and most of the oil coming from the oil pipe directly flowed into the reduction gear box from the oil return hole. The angle of the oil return hole is adjusted to maintain a certain oil level in the bearing housing, and the operation is normal.
2. The lubricating oil tube is blocked by foreign matter
Because the lubrication management is not strict, the container is dirty during the oil-changing process, or the pipe welding and pickling are not standardized, which causes the welding slag and other debris to enter the oil pipe and block the oil hole. It is more common in the previous project.
For example, the raw material grinding reducer of ZB Company is blocked by the oil circuit. The cement grinding reducer of TH Company is also the long-term high temperature of the bearing caused by the blockage of the oil circuit by the cotton yarn. In particular, when the high-speed shaft bearing of the reducer of TH company is used to check the oil quantity, it is always impossible to see how much oil can be added in the high-speed bearing. After completely removing the oil pipe and purging it with high-pressure air, it is found that two fine pieces are blocked inside. Cotton rope!
In addition, in the process of replacing the reducer bearing, TH Company also found that the bearing eccentric sleeve is too thin (the oil hole of the eccentric sleeve can be larger than the diameter of the oil hole of the bearing itself), so the oil hole is reamed. deal with.
Since the bearings of various parts of the hardened gear reducer are generally forcedly lubricated by the thin oil station, the oil pipes of each lubrication point are in parallel relationship. It is difficult to find the blockage of individual oil pipes when observing the total oil quantity and oil return quantity, so there is experience. The maintenance personnel will carefully check the temperature of each tubing and judge whether the oil passage is unblocked according to the temperature difference of the tubing. Generally, the oil pipe temperature is lower than other pipes.
PY company's inspection personnel have found that the high-speed shaft tubing temperature of the reducer in the kiln is low and finally confirms the serious hidden danger of the tubing blockage, thus avoiding a major accident.
3, lubricating oil (fat) deterioration or refueling is not timely
The lubricating oil (or grease) used in the rolling bearing has a certain working temperature. When the temperature is too high, the water in the bearing housing enters the water, and the ash enters the ash, severe oxidation, emulsification and the like may occur, thereby losing the lubricating effect and causing the bearing to be heated. Burned. In addition, the lubricating oil (or grease) itself is poor in texture or the fueling (fat) in operation is not timely, which is also a common phenomenon, such as belt conveyor roller bearings into the rainwater, rotary feeder bearings and Fuller pump bearings into the coal powder or raw The powder will cause the bearing temperature to rise or produce abnormal sound.
4. The fouling of the cooler of the lubrication line is blocked, resulting in poor cooling effect.
Especially in summer production, this problem is particularly common, and individual manufacturers do not hesitate to increase or parallel the cooler to enhance the cooling effect. Because of the serious fouling of the high-temperature fan cooler, frequent bearing alarms have been encountered in various branches. A more effective treatment is to pickle and descale the cooler before entering the summer.
