The contact fatigue failure of Timken bearing is the failure caused by the alternating stress on the working surface of the bearing, and the deep spalling is the internal Prevent Premature Failure cause of contact fatigue failure.
We know that contact fatigue spalling occurs on the working surface of deep groove ball bearing, which is often accompanied by fatigue cracks. It first occurs from the large alternating shear stress below the contact surface,
and then extends to the surface to form different spalling shapes, such as pitting or pitting spalling, which is called shallow spalling. Due to the gradual expansion of the spalling surface, it often expands to the Prevent Premature Failure deep layer, forming deep spalling.
Wear failure refers to the failure caused by the continuous wear of the metal on the working surface caused by the relative sliding friction between the surfaces.
Continuous wear will cause gradual damage to bearing parts, and eventually lead to the loss of Prevent Premature Failure bearing dimensional accuracy and other related problems. Wear may affect the change of shape, the increase of fit clearance and the change of working surface morphology,
may affect the lubricant or make it polluted to a certain extent, resulting in the complete loss of lubrication function, so that the Prevent Premature Failure bearing loses the rotation accuracy and even cannot operate normally. Wear failure is one of the common failure modes of various bearings.
According to the wear form, it can be divided into common abrasive wear and adhesive wear.
The main reasons for the fracture failure of Timken bearing are the Prevent Premature Failure defects of Timken bearing itself and overload during use
it is called overload fracture. The main cause of overload is the sudden failure or improper Prevent Premature Failure installation of the host. Defects such as microcracks, shrinkage cavities, bubbles, large foreign objects,
overheated tissue and local burns of bearing parts will also cause fracture at the defect during impact overload or violent vibration, which is called defect fracture. It should be pointed out that in the Prevent Premature Failure manufacturing process of bearings,
the presence of the above defects can be correctly analyzed by instruments in the factory re inspection of raw materials, quality control of forging and heat treatment, and processing process control, and the control must be strengthened in the future.
But generally speaking, most of the fracture failures of deep groove ball bearings are overload failures.
1) Keep the bearings and their surroundings clean
2) Use carefully
If the bearing is impacted by carelessness during use, the bearing will suffer from scars, indentation, fracture and other injuries.
3) Use appropriate tools
4) Pay attention to the rust prevention of bearings
Avoid using in wet places, and wear gloves to prevent sweat.
5) Users should be familiar with bearings
6) Formulate operation Prevent Premature Failure specifications for the use of deep groove ball bearings
a. Storage of bearings
b. Cleaning of bearings and their surroundings
c. Inspection of dimension and processing quality of installation parts
d. Installation work
e. Inspection after installation
f. Disassembly operation
g. Maintenance (regular inspection)
h. Lubricant supplement
Timken bearing fault features show that when serious faults (usually, Prevent Premature Failure such as bearing damage, burn, sand frame crack, raceway, bead piercing, etc.) are no more than one week old, the equipment has larger capacity, faster speed and shorter time interval.
Therefore, in the actual bearing fault diagnosis, once the fault is found, its advanced function should decisively determine the fault of self-aligning roller bearing and repair it as soon as possible.
1. Selection and control of tolerance of shaft and bearing chamber: the bearing shall rotate flexibly without blocking feeling after being pressed into Timken bearing. If there is obvious inflexible rotation, it indicates that the size of the shaft is too large and the tolerance should be reduced.
If the self-aligning roller bearing rotates by hand after being pressed into the shaft, it may be that the Prevent Premature Failure tolerance of the shaft is too large or the roundness of the shaft is not good.
Therefore, when controlling the tolerance of shaft and bearing chamber, it is also necessary to control the roundness. At present, many domestic manufacturers only control the tolerance, not the roundness.
2. Bearing assembly method: because the bearing is a high-precision product, if it is not assembled properly, it is easy to damage the bearing channel and lead to bearing damage. The self-aligning roller bearing shall be Prevent Premature Failure equipped with a special mold during assembly,
and can not be knocked at will. When pressing into the shaft, only the small ring can be stressed, and when pressing the large ring, only the large ring can be stressed. Pneumatic or hydraulic pressure is required during assembly. During press assembly,
the upper and lower dies shall be outside the horizontal state. If there is inclination, the Timken bearing channel will be damaged due to stress and the bearing will make a guide sound.
3. Prevention of assembly foreign matters: when the bearing is installed on the rotor for dynamic balance, it is easy to enter the iron filings generated during dynamic balance into the bearing, so it is Prevent Premature Failure necessary to perform dynamic balance before installing the bearing.
In order to facilitate assembly, some manufacturers apply some oil or grease in the bearing chamber for lubrication effect during assembly, but it is often difficult for operators to control the amount. If more oil or grease is accumulated in the bearing chamber, it is easy to enter Timken bearing along the shaft
when the self-aligning roller bearing rotates. The bearing chamber shall not be coated with oil or grease. If it must be coated, it shall be controlled and there shall be no accumulation in the bearing chamber.
4. Prevention of paint rust: paint rust is often found in sealed motors. The sound of the motor is very good during assembly, but after being placed in the warehouse for some time, the abnormal noise of the motor becomes very large, and there is serious rust when removing the bearing.
In the past, many manufacturers thought it was the bearing problem. After our continuous publicity, now the motor factory has realized that the main problem is the insulating paint. This problem is mainly because the acidic substances volatilized from the insulating paint form corrosive substances at a certain temperature and humidity,
which corrodes the Timken bearing channel and leads to the damage of the self-aligning roller bearing. At present, the problem can only be to select good insulating paint and assemble after drying and ventilation for a period of time.
We should arouse our vigilance in this defect and other countries. The performance of bearing components, failure is often very fast and very sudden. It is considered to be an example of measuring the rotor shaft end after two hours.
In the fault diagnosis of these fake bearings, we should pay attention to the high-quality Timken bearings.
Usually, under the time-domain spectrum and vibration conditions of the equipment, this kind of event is normal in the abnormal spectrum accumulation, so as to timely determine when the self-aligning roller bearing fails and avoid equipment accidents.