ASME B29-100:2002 pdf download PRECISION POWER TRANSMISSION ROLLER CHAINS, ATTACHMENTS, AND SPROCKETS
3.2 Classes of Sprockets This Standard provides for two classes of sprockets, commercial and precision. Use of commercial or preci- sion sprockets is a matter of drive application judgment. The usual moderate-to-slow speed commercial drive is adequately served by commercial sprockets. Where extreme high speed in combination with high load is involved, or where the drive involves fixed centers, criti- cal timing or register problems, or close clearance with outside interference, then the use of precision sprockets may be more appropriate. As a general guide, drives requiring Type A or Type B lubrication would be served by commercial sprockets. Drives requiring Type C lubrication may require preci- sion sprockets, although even here commercial may be satisfactory. Consult the manufacturer. Types of lubrica- tion are shown in the horsepower ratings tables (Tables A4 through A17) provided in Nonmandatory Appendix A.
3.3 Tooth Section Profile The tooth section profile, Sections A and B of Tables 7A and 7B, shows the recommended chamfering of sprocket teeth for roller chains. All sprocket flanges are to be chamfered to provide guidance of the chain onto the sprocket in case of misalignment due to sprocket misalignmentorpermissible flangeweave. Flangechamfer may be as in Section A or B, or anything in between. The sprocket chamfer dimensions R c , g, and h are non- critical and are given only as a guide for general design proportions.
3.4 Sprocket Flange Location and Thickness See Fig. 5 and Tables 8A, 8B, 8C, 8D, 9A, and 9B.
3.5 Tooth Form Dimensions The tooth form shown in Fig. 6 is a theoretical form for the specific number of teeth N and is designed so that the chain, as it wears and elongates, will ride out toward the tips of the teeth. Because of the variety of ways to produce sprocket teeth, the actual teeth may not exactly match the theoretical form. In the case of space cutters or milling cutters, it is common practice to design cutters to cut a form for an intermediate num- ber of teeth for one of five ranges. This results in the cutter, the sprocket, and the theoretical form matching only at 56 teeth. In the case of hobs or shapers, the generated sprocket tooth form comes very close to the theoretical form for all numbers of teeth, but actually matches only where and if the cutting tool design is based on a specific whole number ofteeth. Cast, powder metal, or plastic molded teeth may or may not match the theoretical form, depending on how their pattern, die, or mold was designed and formed. All of these forms have proved to be acceptable in service. The important thing is that the seating curve diameter, bot- tom diameter, flange width, and chordal pitch be such as to acceptthe meshing chain withoutwedging or bind- ing, so as to minimize chain loading and impact. (For additional information on cutting tools, see Nonmanda- tory Appendix A.)
ASME B29-100:2002 pdf download
PS:Thank you for your support!
