ABMA 21.2:1988(R1999) pdf download

ABMA 21.2:1988(R1999) pdf download.Thrust Needle Roller and Cage Assemblies and Thrust Washers – lnch Design
1. SCOPE
This standard for inch thrust needle roller and cage assemblies and thrust washers covers: ldentification 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 availbility, 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 different makes of standard thrust needle roller and cage assemblies and thrust washers of the same size may depend on bearing 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 require- ments 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 dimensional interchangeability. This code establishes a universal language for describing and identifying inch design thrust needle roller and cage assemblies and thrust washers in order to facilitate communication between the user and the manufacturer. The code is also intended to simplify the handling by user personnel of identical bearings made by different manufacturers, whose identification numbers may be different. This code applies only to those inch design thrust needle roller and cage assemblies and thrust washers 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 a type symbol made up of a group of letters and finally 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, “0″ represents any code numeral and“A” rep- resents any code letter. The bore diameter is indicated by two numerals in sixteenths of an inch comprising the diameter symbol as shown in Boundary Dimension Tables 1 and 2. The type is indicated by a“T” to identify a thrust bearing and two letters comprising the type sym- bol 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 ilustrate the application and meaning of typical identification codes for inch design thrust needle roller and cage assem- blies and for thrust washers. 40TNR461. From 2.2 TNR is found to be the type symbol for a thrust needle roller and cage assembly. Table 1 lists the Boundary Dimensions for type TNR. Referring to Table 1, the diameter symbol 40 indicates a bore diameter of 2.5 inches (63.500 mm) and the dimension series symbol 461 indicates an outside diameter of 3.25 inches (82.550 mm) and a roller diameter of 0.0781 inches (1.984 mm). 12TNP459. From 2.2 TNP is found to be the type symbol for a thrust washer. Table 2 lists the Boundary Dimensions for type TNP. Referring to Table 2, the diameter symbol 12 indicates a bore diameter of 0.75 inches (19.050 mm) and the dimension series symbol 459 indicates an out- side diameter of 1.25 inches (31.750 mm) and a thickness of 0. 1260 inches (3.200 mm).