ABMA 12.1:1992(S2010) pdf download.Load Instrument Ball Bearings Metric Design ANSI/ABMA 12.1:1992
1. SCOPE
1.1 This standard covers the characteristics that define metric design instrument ball bearings, their boundary dimensions, tolerances, internal clearances, classification for selective assembly, and recommended practices for gaging, friction torque determination, load rating, operational life prediction and yield rate limitation. 1.2 The standard applies only to the size ranges covered by Paragraph 4, Boundary Dimensions.
2. CHARACTERISTICS
2.1 Instrument ball bearings comprise bearings with functional requirements for use in any unit that can, in a general sense, be characterized as an instrument. 2.2 Instrument ball bearings must be particularly free from foreign matter and are typically applied to meet one or more of the following characteristics: a. Positional accuracy. b. Low friction torque. c. Smoothness of operation. d. Yield rate limitation. Due to the many specialized requirements that exist in instrument applications, specifications for these characteristics should be established only after full agreement between the manufacturer and the user. 2.3 Instrument precision ball bearings meet tolerances specified in Classes ABEC 5P, ABEC 7P, ABEC 9P, ABEC 5T and ABEC 7T and may reflect specific requirements against one or more of the characteristics of Paragraph 2.2 above. 2.4 Instrument semi-precision ball bearings meet tolerances specified in Class ABEC 3P.
3. SYMBOLS
THE SYMBOLS USED IN THIS STANDARD HAVE THE FOLLOWING MEANINGS:d = bearing bore diameter, basic d s = single bore diameter ∆ ds = deviation of a single bore diameter (difference between a single diameter and the basic diameter) V ds = bore diameter variation (difference between the largest and the smallest actual single bore diameters of one individual ring) d m = mean bore diameter (arithmetical mean of the largest and the smallest actual single bore diameters of one individual ring) ∆ dm = mean bore diameter deviation (difference between the mean bore diameter and the basic bore diameter) d mp = single plane mean bore (arithmetical mean of the largest and the smallest actual single a single radial plane) ∆ dmp = single plane mean bore diameter deviation (difference between a single plane mean bore diameter and the basic bore diameter) V dp = bore diameter variation in a single radial plane (difference between the largest and the smallest actual single bore diameters in a single radial plane) V dmp = mean bore diameter variation (difference between the largest and the smallest actual single plane mean bore diameters of one individual ring) D = bearing outside diameter, basic D s = single outside diameter ∆ Ds = deviation of a single outside diameter (difference between a single outside diameter and the basic outside diameter) V Ds = outside diameter variation (difference between the largest and the smallest actual single outside diameters of one individual ring) D m = mean outside diameter (arithmetical mean of the largest and the smallest actual single outside diameters of one individual ring)∆ Dm = mean outside diameter deviation (difference between the mean outside diameter and the basic outside diameter) D mp = single plane mean outside diameter (arithmetical mean of the largest and the smallest actual single outside diameters in a single radial plane) ∆ Dmp = single plane mean outside diameter deviation (difference between a single plane mean outside diameter and the basic outside diameter) V Dp = outside diameter variation in a single radial plane (difference between the largest and the smallest actual single outside diameters in a single radial plane) V Dpm = mean outside diameter variation (difference between the largest and the smallest actual single plane mean outside diameters of one individual ring)
ABMA 12.1:1992(S2010) pdf download
