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Bearing vibration and noise, both general mechanical vibration and noise in common, but also its characteristics. In addition to lubrication, installation and use of the process-induced vibration and noise, the bearing itself has less vibration and noise characteristics.
1, the bearing vibration characteristics
(1) The reason is very complex bearing vibration, the vibration in the form of radial vibration, axial vibration.
(2) due to the structure of the bearing, which itself has a natural vibration can not be avoided: ① rolling bearing area by vibration; ② ferrule bending vibration under load.
(3) in the existing manufacturing level, bearing vibration mainly ring raceway and rolling elements waviness, but not with roundness and surface roughness of the non-significant correlation.
(4) bearing vibration contain from low to high frequency vibration of the various frequency components, that is, its vibration frequency is everywhere dense.
(5) full-band bearing vibration measuring range of 50-10 000 Hz. In order to facilitate the analysis, the whole band will be divided into three bands: 50 ~ 300 Hz; 300-1 800 Hz 800-10 000Hz.
2, the bearing noise characteristics
(1) bearing noise generated by the vibration caused by many factors, which affect mainly the larger ring raceway and rolling elements of surface roughness and waviness.
(2) the importance of bearing noise sound source also includes the rolling element and crash cage, cage whirl arising due howling, rolling element and raceway contact friction sound (lubrication bad) and so on.
(3) bearing sound frequencies, the background noise has white noise characteristics, but abnormal noise frequency components are mainly concentrated in the 1000-10 000 Hz, ie, the general performance of the bearing noise, high-frequency noise.
(4) Order of noise measurement range of the whole band 100-15 000 Hz (there's at 125 -16 000 Hz).
According to the above vibration and noise characteristics of the frequency components, usually said all along, is not its main purpose is to control the vibration, but to control noise. Such as Japan, from 1933, began lowering the motor bearing vibration research, because there was too much noise motor operation; U.S. painstaking research began in World War II submarine bearing vibration reduction, but also because the German submarine sonar to capture engine noise while working. So, to say, in order to control the bearing noise, it has been indirectly controlled bearing vibration. Now, bearing vibration or noise control, from the past mainly for motor deep groove ball bearings, the development of angular contact ball bearings, cylindrical roller for bearings, tapered roller bearings in, and even self-aligning roller bearings, and many other types. Vibration and noise in a number of these bearings have become the most important application of dynamic performance. Especially for home appliances, office equipment and other bearings, more stringent requirements, we need a "silent bearings", which requires the use of air conditioners bearing even "super silent bearing." Therefore, in such purpose bearings final inspection of the production process, should be carried out vibration or noise for 100% of the full measurement control.
Of course, in terms of monitoring and diagnosis of bearing failure, the use of vibration than the noise to be easy to implement and is much more reliable, so vibration is undoubtedly the main research directions. However, this does not belong to the bearing itself, but it belongs to the bearing application problems, should matter.
Since the bearing vibration and noise, this direct correlation, under certain conditions, can be said to be synonymous, so that the production and use, there is always the "noise vibration" together, "low vibration bearings" are often used to sex described as "low-noise bearings", the reason is this.
Controlled by controlling the bearing vibration bearing noise, not only directly captures the noise source and origin, but also because it is relatively simple to achieve, such as measuring the vibration less affected by environmental conditions, foundation vibration easy to separate for easy application in the actual production. The measurement noise is higher on the environmental conditions, need to have a very low background noise, it is generally higher construction costs must be anechoic room.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 7922CDB NSK | 110 | 150 | 20 |
| 7922A5DB NSK | 110 | 150 | 20 |