ABMA 11:1990 R1999 pdf free
ABMA 11:1990 R1999 pdf free.Load Ratings and Fatigue Life for Roller Bearings
Truncated Contact Area. This stan-dard may not be safely applied to roller bearings subjected to loading which causes the contact area of the roller with the raceway to be truncated by the edge of the raceway or roller. This limitation de-pends strongly on details of bearing design which are not standardized.
Materials. This standard applies to roller bearings made from hardened, good quality bearing steel. While a complete me-tallurgical 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 rollers.
Bearing Types. The fcm factors specified in basic load rating formulae are valid only for those roller bearing configu-rations 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 re-places.
Ring Support and Alignment. Basic rating life calculated according to this stan-dard 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.
Internal Clearance. Radial roller bearing basic rating life calculated accord-ing to this standard is based on the as-sumption that only a nominal internal clear-ance occurs in the mounted bearing at operating speed, load and temperature.
High Speed Effects. Basic rating life calculated according to this standard does not account for high speed effects such as roller centrifugal forces and gy-roscopic moments. These effects tend to diminish fatigue life. Analytical evaluation of these effects frequently requires the use of high speed digital computation devices and hence, cannot be included herein.ABMA 11 pdf free download.
