In the process of using NSK Bearings, various noises are often encountered. Today, let’s analyze the unusual noise: raceway noise.
Raceway noise is a kind of stable and continuous noise excited by the rolling body rolling Nsk Bearing in the raceway when the bearing rotates. People pay attention to it only when its sound pressure level or tone is very large.
In fact, the sound energy excited by the raceway sound is limited. For example, under normal conditions, the high-quality 6203 bearing raceway sound is 25 ~ 27db. This noise is typical of single row deep groove ball bearings Nsk Bearing bearing radial load, which has the following characteristics:
a. Noise and vibration are random;
b. The vibration frequency is above 1kHz;
c. No matter how the rotating speed changes, the dominant frequency of noise is almost unchanged, and the sound pressure level increases Nsk Bearing with the increase of rotating speed;
d. When the radial clearance increases, the sound pressure level increases sharply;
e. When the rigidity of bearing pedestal increases, the lower the total sound pressure level is, Nsk Bearing even if the speed increases, the total sound pressure level does not increase much;
f. The higher the viscosity of lubricant, the lower the sound pressure level, but for grease lubrication, its viscosity and the shape and size of soap fiber Nsk Bearing can affect the noise value.
is caused by the natural vibration of ferrule after being loaded. The elastic contact between the Nsk Bearing ferrule and the rolling body constitutes a nonlinear vibration system. When the lubrication or machining accuracy is not high, the natural vibration related to this elastic feature will be excited, and it will become noise when transmitted to the air.
As we all know, even if the contemporary superb manufacturing technology is used to process bearing parts, there will always be small geometric errors in varying degrees on the working surface, resulting in small fluctuations Nsk Bearing between the raceway and the rolling body and exciting the natural vibration of the vibration system.
Although the raceway noise of NSK bearing is inevitable, high-precision machining of the working surface of parts, correct selection of bearings and accurate use of bearings Nsk Bearing can be adopted to reduce noise and vibration.
The main reasons for the fracture failure of imported bearings are defects and overload. When the external load exceeds the material strength limit and causes the part to break, it is called overload fracture. Overload is mainly caused by sudden failure or improper installation of the host.
Defects such as microcracks, shrinkage cavities, bubbles, Nsk Bearing large foreign objects, overheated tissue and local burns of bearing parts will also cause fracture at the defect during impact overload or severe vibration, which is called defect fracture.
It should be pointed out that in the manufacturing process of bearings, the presence of the above defects can be correctly analyzed by instruments in the factory re inspection of Nsk Bearing raw materials, quality control of forging and heat treatment, and processing process control, and the control must still be strengthened in the future. But generally speaking, most of the bearing fracture failures are overload failures.
Abrasive wear refers to the wear caused by the relative movement of the contact surface due to the extrusion of Nsk Bearing foreign hard particles or hard foreign matters or wear debris on the metal surface between the working surfaces of imported bearings, which often causes furrow like scratches on the working surfaces of bearings.
Hard particles or foreign matters may come from the inside of the host machine or from other adjacent parts of the host system and are sent into the bearing by the lubricating medium. Adhesive wear refers to the uneven stress on the friction surface due to the micro bulge or foreign matter on the friction surface.
When the lubrication conditions are seriously deteriorated, the local deformation and friction micro welding of the friction surface are easy to be caused due to the heat generated by local friction. In serious cases, the surface metal may be locally melted, and the force on the contact surface will tear the local friction welding point from the substrate and increase the plastic deformation.
This cyclic process of adhesion tear adhesion constitutes adhesive wear. Generally Nsk Bearing speaking, slight adhesive wear is called scratch and severe adhesive wear is called bite.