Industry trends

Common quality problems and causes of bearing ring surface

The bearing ring raceway is the surface of the bearing workpiece, and its quality will directly affect the working performance and service life of the bearing. In the course of use, we will often find some common quality problems on the surface of bearing rings. How do these quality problems arise? I have many years of experience to tell you the common quality problems on the surface of bearing rings and their causes.
Reasons for poor surface roughness: insufficient super finishing time, too high pressure of the grindstone, relatively high vibration frequency of the grindstone, and too low speed of the fine super finishing workpiece.
After superfinishing, the convex particles of different sizes and shapes are formed on the machined surface after superfinishing. This is mainly because the grinding particles are sintered on the machined surface under the action of instantaneous high temperature and high pressure. Its existence increases the vibration of the bearing. Value, reducing the service life of the bearing.
Cause: The pressure of the grindstone is too high. Before superfinishing, the surface roughness value is too high, the workpiece speed is too high, the cutting lubricating fluid is not sufficiently cooled, and the remanence of the grinding of the cylindrical roller bearing ring is too large.
Net-like scratches on the surface of the silk after super-finishing. Causes: there are too many impurities in the grindstone and uneven particle size; impurities in the cutting fluid and insufficient flushing.
In the process of super finishing of comet marks, due to the individual large diamond particles falling off or blocking the low recesses on the surface of the workpiece, comet marks are formed along with the super finishing pressure and the rotation of the workpiece. Cause: Choose the grindstone correctly and reduce the pressure of the grindstone.
Reasons for the grinding wheel: the grinding wheel flower is too coarse during surface grinding, the workpiece speed is too high during rough and super finishing, the rough and super finishing time is too short, the pressure of the grinding stone is too small during rough and super finishing, and the swing angle of the grinding stone is too small.
Reasons for excessive axial movement of the end face: too small workpiece eccentricity, resulting in unstable rotation of the workpiece, large radial circle runout, misalignment between the center of grindstone swing and the curvature center of the workpiece raceway, and impurities on the end face supporting surface when the workpiece is positioned As a result, the axial movement of the end face is too large, the geometric accuracy of the grinding process is not good, and the workpiece has been repaired many times.
Causes of poor roundness and waviness: too small workpiece eccentricity; excessively high precision machining workpiece speed, causing machine tool vibration; insufficient grindstone width, too small wrap angle; roller positioning support angle is too small to be driven The ferrule rotates normally; the roundness and ripple of the grinding process are too large.
After the ball bearing raceway is super-finished, the raceway curvature is not good. Cause: The swing center and the raceway curvature center do not coincide: the width of the grindstone is too large, and the wrap angle is too large.