Ball bearing Friction coefficient decreases with the increase of steel ball diameter,as the radius of groove curvature coefficient changes in a small range, its effect on the friction coefficient is not significant; friction coefficient increases with the increase of contact angle; with the increase of radial load, the friction coefficient increases.
Ball bearing friction torque, service life and vibration noise are three key parameters to measure the quality of ball bearings. Three key parameters of the quality of rolling bearings. At present, the fatigue life of bearings has been more More research results, there are more reports on the research of bearing vibration noise. The research on the frictional torque of ball bearings is still at the stage of empirical estimation and sample The research on bearing friction torque is still at the stage of empirical estimation and sample measurement.
At present, the vibration and noise problems of bearings have become a hot topic of research. The vibration and noise of bearings are mainly caused by the internal The vibration and noise of the bearing are mainly caused by the friction force inside the bearing. In the study of noise, the instability of friction The surface roughness and pollutants can lead to noise and noise in the bearing operation. The generation of sound. The contamination of bearings can be avoided, but frictional vibration The sounding of friction vibration and the sounding of percussion vibration are inevitable.
1.between the rolling body and the raceway.
2.pure sliding friction in the sliding contact area.
3.Viscous friction of the lubricant.
Differential sliding refers to the curved bus line contact bearing, subject to load in addition to the relative axis of rotation of the two objects and the contact surface intersection of the two points, the other points on the contact surface of the two objects are not the same linear velocity, resulting in microscopic sliding, called differential sliding. Differential sliding and rolling body and the raceway between the closeness of closely related, the greater the closeness, the greater the differential interaction.
Spin sliding: in the contact angle greater than zero in the ball and roller bearings (except tapered roller bearings), the rolling body around the raceway contact surface normal to the rotational motion caused by the sliding called spin sliding
Spin sliding is an important factor of friction in high-speed angular contact ball bearings
(1) reduce the spin-roll ratio, can reduce the spin-slip.
(2) reduce the slip-roll ratio, the spin-slip is reduced.
(3) contact angle is reduced, the slip-roll ratio is reduced
Low-speed thrust cylindrical roller bearings, because the contact angle of 90 ° spin sliding is very serious, in each pocket hole with a few short rollers instead of a long roller, can reduce spin sliding.
High-speed light load bearing: due to the role of centrifugal force → rolling body pressed to the outer raceway → caused by the inner raceway on the rolling body friction drag force is insufficient → inner ring relative to the rolling body slippage. Slippage is a serious sliding friction.
High-speed light load angular contact ball bearing, the gyroscopic rotation of the steel ball is also a serious sliding friction.
Preventive measures: add axial preload, increase the friction coefficient, reduce the friction angle
