ABMA 21.1:1988(R1999) pdf download

ABMA 21.1:1988(R1999) pdf download.Thrust Needle Roller and Cage Assemblies and Thrust Washers Metric Design
1. SCOPE
Diameîer WO – This standard for metric thrust needle roller and cage assemblies and thrust washers includes: Identification Code Symbols and Nomenclature Boundary Dimensions Tolerances Mounting Practice All thrust needle roller and cage assemblies and thrust washers listed in this standard are not necessarily available. For availability consult bearing manufacturers. Other applicable stan- dards should be consulted for tolerance defini- tions, gaging practices and methods of evaluating load ratings. This standard only covers external dimensions. Functional interchangeability between makers of standard thrust needle roller and cage assem- blies and thrust washers of the same size may depend on features which are not standardized. Hence the substitution of one make of a standard bearing for another should only be made after careful comparison of their characteristics and consideration of the requirements of the particular application.
2. IDENTIFICATION CODE
2.1 General-This code identifies and as far as possible describes each thrust needle roller and cage assembly or thrust washer on the basis of complete interchangeability. This code estab- lishes a universal language for describing and identifying assemblies and washers in order to facilitate communications between the user and the manufacturer. The code is also intended to simplify the handling by user personnel of iden- tical assemblies or washers made by different manufacturers whose identification numbers may be different.This code applies only to those metric thrust needle roller and cage assemblies or thrust wash- ers whose boundary dimensions and tolerances conform to this standard. 2.2 Structure of the Code-As shown in the following table, Schematic Arrangement of a Complete Code Number, the code consists of one or two sections. Section 1, called the Basic Number, includes a diameter symbol made up of a group of numer- als, followed by atype symbol made up of agroup of letters and finally by a dimension series symbol made up of a group of numerals. This Basic Num- ber must always be used. Section 2, pertains only to thrust needle roller and cage assemblies, and when used delineates cage materials. In the Schematic Arrangement Table below, “O” represents any code numeral and “A” rep- resents any code letter.The bore diameter is indicated by two or three numerals comprising the diameter symbol as shown in Boundary Dimension Tables 1 and 2. The type is indicated by two or three letters comprising the type symbol as shown in 2.2.2. The dimension series is indicated by two numerals which describes the outside diameter and roller diameter (or washer thickness) as shown in Boundary Dimension Tables 1 and 2.2 2 4 Coding Examples The following examples illustrate the application and meaning of typical identification codes for thrust needle roller and cage assemblies and for thrust washers.35NT01. From 2.2.2, NT is found to be the type symbol for a thrust needle roller and cage assem- bly and Table 1 lists the Boundary Dimensions for type NT. Referring to Table 1, the diameter symbol 35 indicates a bore diameter of 35mm (1 .3780 inch) and the Dimension series symbol 01 indicates an outside diameter of 52mm (2.0472 inch) and a roller diameter of 2mm (0.07874 inch). From 2.2.3, the absence of a letter indicates that the cage material is steel. 35NTW14. From2.2.2, NTW is found to be the type symbol for a thrust washer and Table 2 lists the Boundary Dimensions for type NTW. Referring to Table 2, the diameter symbol 35 indicates a bore of 35mm (1 .3780 inch) and the dimension series symbol 14 indicates an outside diameter of 52mm (2.0472 inch) and a thickness of 1 mm (0.0394 inch).