2013年8月21日星期三

SKF bearings equipment for regular maintenance, operation


SKF bearings equipment for regular maintenance, operation and external parts replacement Bearing test machine were removed for inspection, required in order to determine whether this bearing parts can be used again and record usage of good and bad. Should carefully investigate and record split down the bearing and appearance of the situation. In order to understand and investigate remaining amount of lubricant, after the sampling, to a good wash bearings.
Second, check the SKF bearing raceway, rolling surface and the mating surface of the situation and the state of wear of the cage and other signs of damage and anomalies in particular, to observe the raceway running track. Determine the bearing can be used again, to consider the extent of bearing manufacturer damage, machine performance, the importance of operating conditions, inspection cycles and then later decide.
Test results, if found bearing damage and abnormal situation, please follow identify the reasons for the phenomenon of bearing damage, develop countermeasures. In addition, test results, if there are several flaws words below, bearing it can not be used again, you need to replace the bearings.
a. inner and outer rings, rolling elements, cage cracks and any one of them will be fragmented.
b. inner and outer rings, rolling elements of any one of a release.
c. raceway, ribs, rolling a significant injury card.
d. cage badly worn or loose rivets terrible.
e. raceway, rolling rust and have scars.
f. rolling surface, rolling on and playing a significant indentation marks.
g. inner diameter surface or outer diameter on the creep.
h. overheating discoloration powerful.
i. grease seals and dust sealed bearings to severe damage.
Raceway sound source is to be generated after the load caused by the natural vibration of the ring. Since the elastic rings and rolling contact with nonlinear vibration system constituted. When lubrication or machining accuracy is not high flexibility with this feature will be excited about the inherent vibration transmitted into the air then becomes noise. As we all know, even with the highest levels of modern manufacturing technology machining bearing parts, the work surface there will always be varying degrees of tiny geometric errors, so that between the raceway and rolling elements excite vibrations produce tiny fluctuations inherent in the system vibration.
    Although SKF bearing raceway noise is inevitable, however, precision machined parts can be taken to the work surface, use the correct selection of bearings and precision bearings make noise damping.
    Raceway sound is due to rotation of the bearing rolling elements and the raceway scroll inspire a kind of smooth and continuous noise, only when its sound pressure level or tone when aroused great attention. In fact, inspired raceway sound acoustic energy is limited, as in normal circumstances, high-quality sound of 6203 bearing raceway 25 ~ 27dB. This noise to withstand the radial load row deep groove ball bearings are the most typical, it has the following characteristics:
    a. noise, vibration is random;
    b. vibration frequencies above 1kHz;
    c. regardless of how the speed of change, the main frequency noise is almost constant with the speed and the sound pressure level is increased with the increase;
    d. When the radial clearance increases, the sound pressure level increased dramatically;
    e. bearing stiffness increases, the total sound pressure level is lower, even if the speed increases, the total sound pressure level has also increased little;
    f. the higher viscosity of the lubricant, the lower the sound pressure level, but for grease lubrication, the viscosity, the fiber shape and size soap can affect the noise value.

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