Mechanical equipment of delicate bearing parts, the operation of the state is good or not directly affect the performance of the whole equipment. Cement mechanical equipment, rolling bearing fault by early in case of equipment malfunction. Therefore, find out the fault root causes, and the adoption of remedial measures, eliminate the fault, it is one of the keys to improve the system availability.

1 rolling bearing fault analysis

1.1 the rolling bearing vibration analysis

Rolling FAG bearing the failure of the typical way is its rolling contacts occur simple fatigue spalling. This kind of spalling, surface area is about 2 spalling was, to a depth of 0.2 mm to 0.3 mm can through to judge its vibration monitoring inspection. Flake may happen a circle, the surface, a circle or rolling body. Among them, a circle in the contact stress for higher, fracture situation more.

Used for all kinds of diagnosis technology of rolling bearing, vibration monitoring method is still the main one. Overall, the time domain analysis method is simple and suitable for the noise small occasions, it is the good method of simple diagnosis; The frequency domain diagnosis method, the method of resonant demodulation most mature reliable, and suitable for precision bearing fault diagnosis; Time-frequency analysis method and resonance demodulation method similar, can properly characterize the fault signal of the time and frequency characteristics, more advantages.

1.2 the rolling bearing damage form analysis and remedy

(1) overload. Serious surface spalling and wear, show that the rolling bearing caused by overload SKF early of fatigue failure (in addition with tight also can cause some degree of fatigue). Overload would cause serious bearing steel ball groove wear, large area of spalling and sometimes accompanied by overheating. Remedy is to reduce the load bearing or improve the bearing capacity of the bearing.

(2) overheating. The roller groove, steel ball or keep device change color, show that bearing overheating. Higher temperatures will make lubricant reduces, make oil desert is formed not easily or disappear completely. The temperature too high, can make the groove and steel ball materials annealing, hardness decline. This is mainly cooling disadvantage or overloaded, high speed of not fully by the cooling. Way to solve it is fully heat dissipation, additional cooling.

(3) the low load corrosion vibration. In each of the steel ball axial position to appear on the oval wear trace, this shows that when bearing doesn't work and did not produce oil film, the external vibration excessive or low load vibration caused by corrosion failure. Remedy is to make NTN bearing vibration isolation or in bearing grease with anti-wear additives.

(4) installation problems. Main pay attention to the following aspects:

First, pay attention to force installation. Such as rolling on occurrence interval of pit, show that load is beyond the material elastic limit. This is due to the impact of the static overload or serious (such as the installation has been with a hammer percussion bearing) cause. The correct installation method is only to be pressed to the ring to force (in the shaft jacket lap don't pull in between).

Second, pay attention to the installation of angular contact bearings direction. Angle contact NACHI shaft bearing has a elliptic contact area, and only in a direction bear axial thrust. In the opposite direction when the assembly bearing, for steel ball in groove edge, the loading surface will produce the groove shape wear belt. So in installation should pay attention to the correct installation direction.

Third, pay attention to. Steel ball deflection, don't wear trace and groove direction in parallel, show that when installation, not only on the bearing. If the amount > 16000 deflection, easy cause bearing temperature rising and severe wear. The reason may be shaft have to bend, shaft or box have burr, lock mother of pressure surface not and thread in the vertical axis. Therefore, installation should pay attention to the check jump diameter.

Fourth, we should pay attention to the correct to cooperate. Bearing inner and outer assembly contact surface appear circumference of shape wear or discoloration, is by the bearing and the spare parts of the match with too loose cause. The abrasion of oxide produced for a kind of pure brown abrasive, the result would cause bearing further wear, fever and produce noise and produce diameter jump a series of problems, such as so assembly should pay attention to the correct to cooperate.

And as a groove bottom has serious spherical wear track, it shows that for matching with close make bearing clearance smaller, because the torque is increasing, and bearing temperature rising, making bearing for wear and fatigue and soon failure. At this time, as long as the proper recovery radial clearance, reduced surplus quantity can be solved this problem.

(5) IKO bearing normal fatigue failure. In any operation of the surface (such as groove or steel ball) appears irregular material spalling phenomena, and gradually expanded cause amplitude increase, this is a kind of normal fatigue failure. If the average bearing life can not meet the application requirements, is only to choose the more advanced bearing, or improve the level of bearing specifications, to improve the bearing capacity of the bearing.

(6) the lubrication undeserved. All the rolling bearing all need in high quality lubricants for its continuous lubrication, to keep its design performance. Bearings inside body and a circle on rolling formed on a layer of oil film to prevent metals and metal direct contact between. If good lubrication can reduce the friction, make its not wear.

 
Bearing in the operation state, grease or lubricant viscosity is the key to ensure the normal lubrication; At the same time, lubricating grease keep clean, do not contain solid or liquid impurity is also very important. Oil viscosity is too low, can have sufficient lubrication, to make a circle soon wear. Began, a circle of metal roller metal surface friction direct contact with each other, make its surface grinding very smooth ? and then happen dry friction ? lead to a circle roller surface was crushed grain that chip surface fracturing. At first can observe surface darker, lose luster, eventually forming dent and drop off fatigue. Remedy is according to bearing need, chose to change lubricating oil or grease.

Particle pollution lubricating oil or grease pollutants, even if these pollutants particles less than average oil film thickness, but because of the hard particles ? still can produce abrasion, even through oil film, the bearing surface produces local stress, which significantly shorten TIMKEN bearing life. Lubricating oil or grease the concentration of the water even small to 0.01%, also enough to shorten the bearing the service life of the original half. If water soluble in oil or grease, bearing with water service life of increasing concentration and cut. Remedy for change is not clean oil or grease; At ordinary times shall install good filter, increase seal, storage, when installation, pay attention to cleaning operation.

(7) corrosion. Groove, steel ball, maintains a and the internal and external circle annulus surface appear red or brown stains, show that because of exposure to the corrosion of bearing liquid or gas produced in the corrosion failure. It can cause a vibration increase, the wear is intensified, radial clearance increase, preloading is reduced, and in extreme cases happened fatigue failure. Remedy is to make liquid from bearing the increase of bearing or tossed overall and external seal.

2 the INA bearing fault reason fan and processing method

According to not complete count, cement plant fan vibrate abnormal failure rate is highest when 58.6%, because the vibration will cause fan operation imbalance. Among them, the bearing tight set with adjustment of undeserved, can lead to abnormal bearing temperature rise and vibration.

If a cement plant in equipment maintenance period replacement fan round leaves. Round leaves with tight set on both sides of the self-contained bearing of fixed to cooperate. To test the high temperature occurs free bearing, vibration value is on the high side of the fault.

Apart on the bearing cover, manual slow rotary fan, found in a particular position of the shaft bearing roller, in the load area also have rolling condition, which can be used to determine the running bearings changes on the high side and the installation clearance gap may be insufficient. By that measure, bearing is only 0.04 mm internal clearance, the axis of 0.18 mm eccentric.

Because NACHI bearing the span around to avoid torsion shaft bearings or installation Angle error is difficult, therefore, large fan can be adjusted by each of the spherical roller bearing. But when bearing internal clearance is insufficient, internal rolling bearing a by sports dimensional limitation, the automatic each function affected, instead of vibration value will rise. Bearing clearance with tight internal with the degree of increase and decrease, unable to form the oil film, when running bearings for temperature rise and fall between zero, if bearing operation heat generation is still more than the absence of quantity of heat, the bearing temperature that is quickly to climb. At this moment, if not instant downtime, bearing the burning of the will. With the shaft bearing inner with tight is this example running bearings the cause of the high temperature anomaly.

Processing, left the read just the shaft and the inner with the degree, the replacement of bearing clearance after take 0.10 mm. To installed after the restart fan, bearing vibration value and operating temperature are back to normal.

 
Bearing clearance is too small or parts of internal design and manufacture accuracy is running bearings are the main reason of the higher temperature, for the convenience of fan equipment installation, repair and maintenance and, generally in the design used more tight set pieces bearing inner cone hole with the bearing of the bearings. But also easy to install on the program because of negligence and produces a problem, especially appropriate clearance adjustment. Bearing clearance is too small, and operating temperature internal increased rapidly; Bearing inner cone and the hole with set too loose bearing for matching with loose happens to face in a short period and the burning of the fault.



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