Electric spindleThe rolling track sound of a bearing is a continuous sound produced by the rolling body rolling on the rolling track surface during operation, which is usually a unique sound that occurs in all electric spindle bearings. The usual bearing sound is a combination of raceway sound and other noises. The raceway sound of ball bearings is irregular, with a frequency above 1000 Hz. Its main frequency does not change with the speed, but its total sound pressure level increases with the increase of speed. The sound pressure level of a bearing with a loud raceway noise decreases with the increase of viscosity; The sound pressure level of bearings with low raceway noise changes from decreasing to slightly increasing when the viscosity increases to about 20mm2/s or more. The greater the rigidity of the bearing seat, the lower the total sound pressure level of the raceway sound. If the radial clearance is too small, the total sound pressure level and main frequency of the raceway sound will increase sharply with the reduction of radial clearance. The methods to control the track noise include selecting low-noise electric spindle bearings with very low ripple, and carefully selecting the application conditions. Rolling track noise often affects the overall noise of the machinery, and reducing rolling track noise can reduce the overall noise of the machinery.

The impact sound and control method of rolling bodies: When larger types of ball bearings or cylindrical roller bearings work at low speeds under pure radial loads, due to the small centrifugal force of the rolling body, the rolling body in the non load zone will impact the cage or raceway and produce noise. But as the speed increases, this noise will disappear. The control methods for the impact sound of rolling bodies include: reducing the radial clearance appropriately, and using electric spindle bearings with a reasonable structure and flexible materials.

The electric spindle bearings fail due to continuous wear and tear caused by conflicting resistance during rolling. The resistance that prevents the rotation of the electric spindle bearing consists of three types: rolling conflict, sliding conflict, and smoothing agent conflict. When the rolling body rolls on the bearing raceway, rolling conflict occurs; Sliding conflicts occur on the guide surface of the rolling body in the cage, on the guide surface of the retaining edge, and on the roller end face and the sleeve edge in the roller bearing; The smooth agent conflict is composed of the internal conflict of the smooth agent at the touch and the stirring and kneading of the smooth agent. Therefore, the resistance of impedance bearing motion is the sum of the three conflicts mentioned above. The purpose of smoothness is to use smooth grease and its smoothing method to avoid direct contact between the raceway, rolling body, and cage metal, reduce conflict heat, minimize conflict resistance, thereby reducing wear, avoiding rust, and extending its service life.

About 80% of bearings use smooth grease for smoothing. There are many types of bearings that are injected with grease in the bearing factory and sent to users for use. Therefore, some people refer to smooth grease as the fifth largest component of a bearing, after the four major parts of the inner ring, outer ring, rolling body, and cage. Explain the importance of smooth grease for bearings.