Causes of rolling element burns in angular contact bearings

Specific causes of rolling element burns in angular contact bearings
1. Rolling element line burns (1) Manifestation: Line burns are mostly caused by frictional heat generated on the rolling element surface under the combined influence of force and grinding speed during the grinding process of the bearing steel ball, and burns are caused when the temperature exceeds the metal quenching or tempering temperature.
(2) Causes of failure: The ball distributor and the grinding plate horn do not match, and the ball is not smoothly inserted; the groove of the template or grinding wheel is too deep or does not match the size of the rolling element, affecting the rotation flexibility of the rolling element; the working surface of the grinding plate and the grinding wheel is uneven or the groove depth is inconsistent, causing the steel ball to slip; the grinding plate and the grinding wheel size do not match, etc.
(3) Solution: Adjust the matching size of the template or grinding wheel and the rolling element to make the grinding plate and grinding wheel size match well, pay attention to whether the ball collecting knife plate is worn or deformed, and ensure the ball collecting speed to avoid excessive grinding.
2. Point burns on rolling elements
(1) Manifestation: Point burns are actually caused by the impact of the steel ball on the fixed plate, grinding wheel and other hard points during grinding, which causes the impact point on the steel ball surface to generate temperature. When the impact temperature reaches the quenching or tempering temperature of the metal and is immediately cooled by the coolant, a point-shaped secondary quenching or tempering burn is formed.
(2) Causes of failure: The grinding wheel speed may be too high; the grinding wheel groove cracks or falling blocks cause poor operation; the machine tool spindle bearing is damaged and the equipment amplitude increases; the fixed plate has pores or hard particles and impurities on the surface wear; coolant impurities, etc.
(3) Solution: Control the grinding wheel speed; replace the faulty grinding wheel or machine tool spindle bearing in time; adjust the material tray speed in time to make the ball uniform; and replace the coolant regularly.
3. Bipolar burns on rolling elements
(1) Manifestation: During the grinding process, the steel ball does not contact the entire grinding wheel groove, but only contacts on two sides or one side. The grinding pressure is concentrated at the contact point to generate high temperature, and burns occur when cooled.
(2) Cause of the fault: There is a dead corner in the machine tool or there are foreign objects such as grinding wheel blocks or material heads blocking the groove.
(3) Solution: Adjust the inlet and outlet to avoid dead corners; adjust the groove to remove foreign objects, repair it in time and keep the groove clean.