Machinery's Handbook, 31st Edition
2254 Standards for Spur and Helical Gears Bulk Temperature Thermal Flash Factor is dependent on moduli of elasticity and ther mal contact coefficients of pinion and wheel materials and geometry of the line of action. Welding Factor accounts for different tooth materials and heat treatments. Geometrical Factor is defined as a function of the gear ratio and the dimensionless parameter on the line of action. Integral Temperature Criterion references the integral temperature of the gears, which depends on the lubricant viscosity and tendency toward scuffing and scoring of the gear materials. Examination of the above factors shows the similarity in the approach of the British and the ISO Standards to that of the ANSI/AGMA Standards. Slight variations in the methods used to calculate the factors will result in different allowable stress figures. Experimental work using some of the stressing formulas has shown wide variations and designers must continue to rely on experience to arrive at satisfactory results. Standards Nomenclature All standards are referenced and identified throughout this book by an alphanumeric prefix which designates the organization that administered the development work on the standard, and followed by a standards number. All standards are reviewed by the relevant committees at regular time intervals, as specified by the overseeing standards organization, to determine whether the standard should be confirmed (reissued without changes other than correction of typographical errors), updated, or removed from service. The following is for example use only. ANSI B18.8.2-1984, R1994 is a standard for Taper, Dowel, Straight, Grooved, and Spring Pins. ANSI refers to the American National Standards Institute that is responsible for overseeing the development or approval of the standard, and B18.8.2 is the number of the standard. The first date, 1984, indicates the year in which the standard was issued, and the sequence R1994 indicates that this standard was reviewed and reaffirmed in 1994. The current designation of the standard, ANSI/ ASME B18.8.2-2000 (R2010), indicates that it was revised in 2000; it is ANSI approved; and ASME (American Society of Mechanical Engineers) was the standards body respon sible for development of the standard. This standard is sometimes also designated ASME B18.8.2-2000 (R2010). ISO (International Organization for Standardization) standards use a slightly different format, for example, ISO 5127-1:1983. The entire ISO reference number consists of a pre fix ISO, a serial number, and the year of publication. Aside from content, ISO standards differ from American National standards in that they are often smaller focused documents, which in turn reference other standards or other parts of the same standard. Unlike the numbering scheme used by ANSI, ISO standards related to a particular topic often do not carry sequential numbers nor are they in consecutive series. British Standards Institute standards use the following format: BS 1361: 1971 (1986). The first part is the organization prefix BS, followed by the reference number and the date of issue. The number in parenthesis is the date that the standard was most recently recon firmed. British Standards may also be designated withdrawn (no longer to be used) and obsolescent (going out of use, but may be used for servicing older equipment). Organization Web Address Organization Web Address ISO (International Organization for Standardization) www.iso.ch JIS (Japanese Industrial Standards) www.jisc.org IEC (International Electrotechnical Commission) www.iec.ch ASME (American Society of Mechanical Engineers) www.asme.org ANSI (American National Standards Institute) www.ansi.org SAE (Society of Automotive Engineers) www.sae.org BSI (British Standards Institute) www.bsi-inc.org SME (Society of Manufacturing Engineers) www.sme.org
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