ABMA 18.2:1982(S2013) pdf free

ABMA 18.2:1982(S2013) pdf free.Needle Roller Bearings Radial, Inch Design
This section covers needle roller bearing and component ftting and mounting practice for normal operating conditions. Tables 5.1 – 5.8 list the tolerance limits required for shaft and housing seat diameters for bearings with inner and outer rings as well as limits for raceway diameters where inner and/or outer rings are omitted and the rollers operate directly upon these surfaces. Unusual design and operating conditions may require a departure from these practices. In such cases, bearing manufacturers should be consulted.
Drawn cup needle roller bearings depend on the housings into which they are pressed for their sizes and shapes. Therefore, the housings must not only have the proper bore dimensions but also must have sufficient strength. T ables 5.1-5.2 show the bore tolerance limits for rigid housings such as those made from good quality cast iron or steel of adequate radial section equal to or greater than the ring gauge section given in ANSI Standard B3.4- ABMA Standard 4. Consult the bearing manufacturers for recommendations if the housings must be of lower strength materials such as aluminum or even of steel of thin radial section. The dimensions of the housing bores shall be such that when the mean bore diameter of a housing is measured in each of several radial planes, the maximum difference between these mean diameters shall not exceed 0.013 mm (0.0005 inch) or one-half the housing bore tolerance limit, if smaller. Also, the radial deviation from circular form shall not exceed 0.006 mm (0.00025 inch). The arithmetic mean surface roughness (Ra) shall not exceed
Most drawn cup needle roller bearings do not use inner rings; they operate directly on the surfaces of shafts. When shafts are used as inner raceways, they shall be made of bearing quality steel hardened to 58 HRC (655 HV) minimum. Tables 5.1-5.2 show the shaft raceway tolerance limits.The mean outside diameter of a shaft surface shall be determined in each of several radial planes. The difference between these mean diameters shall not exceed 0.008 mm (0.0003 inch) or one-half the diameter tolerance limit, if smaller. The radial deviation from circular form shall not exceed 0.0025 mm (0.0001 inch) for diameters up to and including 25 mm (one inch). Above 25 mm (one inch) the allowable deviation is 0.0001 times the shaft diameter. The arithmetic mean surface roughness (Ra) shall not exceed 0.4 micrometres (1 6 micro-inches).ABMA 18.2 pdf free download.