Was dismantled when regular maintenance checks bearing equipment, running checks and peripheral parts replacement, to determine whether the use of an inferior race again or use of good and bad. To carefully investigate and record split down the bearing and appearance of the case, in order to clarify and investigate the remaining amount of lubricant, after sampling, to good wash bearings. Second, check the raceway, the rolling surface and the mating surface condition and cage wear status without damage and anomalies.
Can be used again to determine the bearing to come back at a later decision to consider the extent of bearing damage, mechanical properties, the importance of operating conditions, inspection cycle. Test results, if found bearing damage and abnormal situation, identify the reasons for the development of countermeasures. In addition, test results, if there are several flaws in the following words, the bearing can not be used again, the need to replace the new bearings.
a. inner and outer rings, rolling elements, cage and any one of them cracks appear debris.
b. inner and outer rings, rolling any one has peeled.
c. raceway, ribs, rolling a significant injury card.
d. keep badly worn or loose rivets cage powerful.
e. raceway, rolling rust and have scars.
f. raceway, and playing a significant indentation marks on the rolling elements.
g. There creep on the inner or outer surface of the inner diameter of the outer diameter.
h. overheat discoloration powerful.
seals and shields damage i. grease sealed bearings serious.
(1), operation inspection and Troubleshooting
Operation check items bearing rolling sound, vibration, temperature, lubrication status, as follows:
A bearing rolling sound
Using sound measuring device for the operation of the rolling bearing size and sound quality inspection, bearing even a slight peeling damage, abnormal tone and irregular tone will be issued with a sound measuring device capable of resolving.
Two, bearing vibration
Bearing vibration of the bearing damage is very sensitive, such as peeling, indentation, corrosion, cracks, wear, etc. will be reflected in the bearing vibration measurement, therefore, through the use of special bearing vibration measurements (frequency analyzer, etc.) to measure the vibration the size, frequency diversity can not be inferred by the abnormal situation. The measured values due to the conditions of use or the sensor mounting position of the bearing, etc., and therefore requires prior to measurements after the analysis of each machine were compared to determine the criteria.
Three, bearing temperature
The bearing temperature, generally room temperature outside the bearing can be inferred, if the use of the hole can be measured directly bearing outer ring temperature, is more appropriate. Typically, the bearing temperature slowly began to rise with the operation, after 1-2 hours to reach steady state. The normal temperature of the bearing due to heat capacity, heat capacity, speed and load of the machine and different. If lubrication, install the appropriate department, the bearing temperature will be rapid-rise, there will be abnormal high temperature, when to stop running and take the necessary precautions.
Fourth, lubrication
1, the role of bearing lubrication
Lubricated rolling bearing fatigue life and friction, wear, temperature, vibration, etc. have a major impact, no normal lubrication, bearings will not work. Analysis showed that the cause of bearing damage, bearing damage and about 40 percent are related to poor lubrication. Therefore, well-lubricated bearing is an effective measure to reduce the bearing friction and wear.
In addition, there are cooling bearing lubrication, rust, sealing, easing the impact of a variety of effects, the role of bearing lubrication can be briefly described as follows:
a. In between the two rolling surfaces or sliding surfaces contact each other to form a film second surface spaced from the contact surface to reduce friction and wear.
b. When When using oil lubrication, especially the use of circulating oil lubrication, oil mist lubrication and spray lubrication and lubricants can take away most of the heat inside the bearing friction, play an effective heat sink.
c. When using grease lubrication, can prevent external dust and other foreign matter from entering the bearing, play a role in the closure.
d. lubricants have to prevent metal corrosion effect.
e. to extend the fatigue life of the bearing.
2. Comparison of grease and oil lubrication
Bearing lubrication method is roughly divided into two lubricating grease and oil. In order to give full play to the bearing function, it is important according to the use and purpose of use Diaojian using lubrication method.
3, for grease lubrication
Grease is the lubricant base oil, thickener and additives composed. When selected, should choose very suitable for bearing grease Run conditions of use, due to the different trademark, the performance will also vary greatly, so choose the time, must pay attention to. Bearing grease used calcium-based grease, grease, sodium, calcium and sodium based grease, lithium grease, aluminum grease and molybdenum disulfide grease. Number of bearing grease filling, to fill the space inside the bearing 1 / 2-1 / 3 as appropriate. Should reduce speed to 1/3. Excessive grease the temperature rises.
4, the choice of grease
When selecting grease in accordance with the operating temperature, the main indicators should be dropping point, oxidation stability and low temperature performance, dropping point temperature is generally used to evaluate the performance of the bearing operating temperature should be lower than the actual drop point 10-20 ℃. The use of synthetic grease dropping point temperature should be below 20-30 ℃. According to the load bearing grease selection of heavy duty should choose a small penetration grease. In addition to the small penetration, but also have a higher film strength and extreme pressure performance when working under pressure. According to the environmental conditions when selecting grease, calcium-based grease easily soluble in water, and water is less suitable for dry environments.
Fifth, oil lubrication
At high speed, high temperature conditions, grease lubrication oil can no longer meet. By lubricant circulation, can take a lot of heat. Viscosity is an important characteristic of the lubricating oil, the viscosity directly affects the size of the oil film thickness between the fluidity and the friction surface is formed of the lubricating oil, the lubricating oil at the bearing operating temperature viscosity generally 12-15cst. The higher the speed should be selected low viscosity, load more weight should choose a higher viscosity. Commonly used lubricating mechanical oil, high-speed machine oil, turbine oil, compressor oil, transformer oil, cylinder oil.
Oil lubrication method comprising:
a. oil bath lubrication
Oil bath lubrication is the most common method of lubrication, for low, medium speed bearing lubrication, bearing part immersed in the tank, the lubricating oil by the rotation of the bearing parts brought up, and then flows back to the oil tank should be slightly lower than the lowest rolling of the central body.
b. drip lubrication
Drip lubrication suitable lubricant needs rationing was bearing components, usually every 3-8 seconds drip drop amount is appropriate, too much oil will cause the bearing temperature increased.
c. circulating oil lubrication
The filtered oil pump oil to the bearing member, through the bearing lubricant filtered again after cooling after use. As the circulating oil can be taken away some heat, bearing cooling, therefore the method is suitable for high speed bearing components.
d. Spray lubrication
With dry lubricant mixed with compressed air through the formation of mist sprayers, spray bearings, air can effectively cool the bearing and prevent intrusion of impurities. This method is suitable for high-speed, high-temperature lubrication of the bearing components.
e. spray lubrication
Oil pump high pressure oil through the nozzle onto the bearing, the bearing oil was injected into the other end of the oil groove flows into the bearing. When the bearing is rotated at high speed, the rolling elements and cages are also at a relatively high rotational speed of the surrounding air to form gas stream by conventional methods is difficult to lubricate the lubricating oil to the bearings, then the lubricant must be sprayed with a high pressure jet method to the bearing, the position of the nozzle should be placed between the holder holding the inner ring and the center.
