Raceway Noise of Bearings and Its Control Measures: Raceway noise is a smooth and continuous sound produced by the rolling elements rolling on the raceway surface when a single bearing is in operation. It is a unique basic sound that occurs in all rolling bearings. The general noise of a bearing is the raceway noise plus other sounds.

The raceway noise of ball bearings is irregular, with a frequency above 1000Hz. Its main frequency does not change with the speed, but the total noise level increases as the speed rises. For bearings with high raceway noise, the noise level of the raceway decreases as the viscosity (of the lubricant) increases. However, when the viscosity (of the lubricant) for bearings with low raceway noise increases to more than 20mm²/s, the noise level changes from decreasing to increasing to a certain extent. The greater the rigidity of the plummer block bearing, the smaller the total noise level.

When the radial internal clearance is too small, as the radial internal clearance decreases, the total noise level and main frequency of the raceway noise increase significantly. The method to control the raceway noise is to use low-noise bearings (i.e., bearings with small waviness) and carefully select and apply the relevant standards. Raceway noise often affects the noise of the entire equipment, so reducing raceway noise can reduce the noise of the entire equipment.

Impact Noise of Rolling Elements and Its Control Measures: When large-sized ball bearings or cylindrical roller bearings operate at low speeds under pure radial loads, the rolling elements in the non-load-bearing area will impact the ball bearing rings or raceways and transmit noise because the centrifugal force of the rolling elements is small. However, this noise will disappear as the speed increases. The control measures for the impact noise of rolling elements include appropriately reducing the radial internal clearance, adopting a reasonable structure, and using bearings made of materials with smooth rolling surfaces.