Common quality problems and causes of bearing ring surface, pay attention!

The raceway of bearing ring is the workpiece surface of bearing, and its quality will directly affect the working performance and service life of bearing. In the process of use, we often find some common quality problems on the surface of bearing rings. How do these quality problems arise? I have compiled many years of experience to tell you the common quality problems and causes of bearing ring surface.

1. Reasons for poor surface roughness: insufficient superfinishing time, too high grinding stone pressure, relatively high grinding stone vibration frequency, and too low workpiece speed for precision superfinishing.

2. Raised particles with different sizes and shapes 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 pressure. Its existence increases the vibration value of the bearing and reduces the service life of the bearing.

Cause: The pressure of the grinding stone is too high. Before superfinishing, the surface roughness value is too high, the workpiece speed is too high, the cutting lubricant is not sufficiently cooled, and the remanence of cylindrical roller bearing ring grinding is too large.

3. Netlike scratches on the machined surface after superfinishing. Causes: There are too many impurities in the grinding stone, and the particle size is uneven; The cutting fluid has impurities and the flushing is insufficient.

4. During the superfinishing process of comet marks, due to individual large diamond particles falling off or blocking in the low recesses of the workpiece surface, comet marks are formed with the superfinishing pressure and workpiece rotation. Causes: correctly select the grinding stone and reduce the pressure of the grinding stone.

5. Reasons for grinding wheel: the grinding wheel is too rough during surface grinding, the workpiece speed is too high during rough and super fine machining, the rough and super fine machining time is too short, the grinding stone pressure is too small during rough and super fine machining, and the grinding stone swing angle is too small.

6. Reasons for excessive axial play of the end face: the eccentricity of the workpiece is too small, resulting in unstable rotation of the workpiece, large radial circular runout, the center of the grinding stone swing and the center of curvature of the workpiece raceway do not coincide, there are sundries on the end bearing surface when the workpiece is positioned, resulting in excessive axial play of the end face, poor geometric accuracy of the grinding process, and repeated rework of the workpiece.

7. Reasons for poor roundness and waviness: the eccentricity of the workpiece is too small; Excessive rotating speed of workpieces for precision and superfinishing will cause machine tool vibration; The width of the grinding stone is not enough, and the wrap angle is too small; The supporting angle is too small to drive the ferrule to rotate normally when the roller is positioned; The roundness and ripple of grinding process are too large.

8. The reason for poor raceway curvature after superfinishing of ball bearing raceway: the swing center does not coincide with the raceway curvature center; the width of the grinding stone is too large, and the wrap angle is too large.