ABMA 9:1990 pdf free

ABMA 9:1990 pdf free.Load Ratings And Fatigue Life For Ball Bearings
Truncated Contact Area. This standard may not be safely applied to ball bearings subjected to loading which causes the contact area of the ball with the raceway to be truncated by the raceway shoulder. This limitation depends strongly on details of bearing design which are not standardized.
Materials. This standard applies to ball bearings made from hardened, good quality bearing steel. While a complete metallurgical description is beyond the scope of this standard, typical cleanliness and material composition specifications for bearing quality steel are given in ASTM A 295 and A 485 for through hardening steels, and in ASTM A 534 for carburizing steels. Typical hardness levels range from HRC 58 to 64 for rings or washers and HRC 60 to 65 for balls.
The fcm factors specified in basic load rating formulae are valid only for those ball bearing configurations specified in section 4.1 above.This standard is not applicable to designs where the rolling elements operate directly on a shaft or housing surface，unless that surface is equivalent in all respects to the bearing ring (or washer) raceway it replaces. This standard is not applicable to instrument ball bearings covered in ANSI/ABMA Standards 12.1 and 12.2.Basic rating life calculated according to this standard is based on the assumption that the bearing is adequately lubricated.
Determination of adequate lubrication depends upon the bearing application. An adequate amount of an appropriate type of lubricant is essential to achieving expected performance. The lubricant must be free of excessive contaminants and of a viscosity level that will provide a film thickness somewhat greater than the rolling contact surfaces composite roughness at the operating temperature.
Basic rating life calculated according to this standard assumes that the bearing inner and outer rings are rigidly supported, and that the inner and outer ring axes are properly aligned. Bearing rings (or washers) must be mounted so that any deformation of rings as a result of mounting compliance is small compared to contact deformation under the applied load.ABMA 9 pdf free download.