ANSI/AGMA 1012-G05 pdf free download.Gear Nomenclature, Definition of Terms with Symbols.
3.2.1 Subscripts
A subscript following the general symbol may be used to indicate a value applying to a particular gear or tool, or a value taken at a particular position or ina
particular direction. For convenience and brevity, it is desirable to use a general symbol without a subscript when only one value of a given kind is involved. Thus, in a spur gear or a straight tooth bevel gear, there is occasion to consider only one cross section of the teeth, namely, the transverse section, and it is convenient and natural to refer, for
instance, simply to the circular pitch, p, and the pressure angle, φ. In the case of gears with oblique teeth, on the other hand, it is usually necessary to be specific and to refer to the transverse pitch, Pt, and the transverse pressure angle,in order not to leave any doubt as to whether values are being given for the transverse plane or normal plane.
3.2.2 Typography
In accordance with the usual practice in published text, symbols, whether upper or lower case, should be printed in serif italic font. This is done to avoid confusion in reading the symbols and to make a distinction between upper and lower case. An exception is Greek capital letters and all subscripts,which are always vertical sans serif font.
Numbers appearing as coefficients, subscripts,superscripts, or exponents should be printed in vertical Arabic numerals. Abbreviations should always be printed vertical and are not recommended for use in formulas. Trigonometric functions should be printed in lower case vertical type. Standard mathematical notation should be followed.
4 Geometric definitions
There is an old Chinese proverb that states: The beginning of wisdom is to call things by their right names. Unfortunately, gearing terms and meanings vary in different offices, shops, textbooks, and among gear authorities.
To obtain related continuity, the terms have been grouped in what may be called a textbook arrangement in preference to alphabetical order. Many of the definitions have been written in a way that makes them depend on one another, as a logical series.
This arrangement leads to a more comprehensive understanding of the concepts and geometrical relations.ANSI/AGMA 1012 pdf download.