 KHK Gear Nomenclature

Manufacturer documentation by KHK: Intermeshing Pitch Circle, definition and the names operating pitch circle and working pitch circle.

The ABCs of Gears, A: The Introductory Course, §7, printed p. 18: diagram distinguishing reference, tip, base and root circles. Basic Gear Terminology and Calculation, reference diameter and module; Calculation of Gear Dimensions, §4.1, operating pitch circles for meshing profile-shifted spur gears.

The ABC's of Gears, Basic Guide B. Manufacturer-authored guide: §1.1, printed pp.4–5, speed ratios and compound gear trains, equations(1.1)–(1.2); §2, printed pp.12–19, module, reference pitch and reference/tip/root diameters, equations(2.1), (2.8)–(2.10), Figure2.6 and Table2.1; §3, printed pp.20–21, involute construction, base/reference circles and equation(3.1). The PDF contains facing printed pages; printed p.15 is PDF page8 and printed pp.20–21 are PDF page11.

Length of Path of Contact: usable contact is the active segment of the involute line of action, and contact ratio is its length divided by base pitch. Basic Guide B §2, printed p.19, equations(2.13)–(2.14), distinguishes normal and transverse helical-gear modules.

Calculation of Gear Dimensions, §4.3, Figure4.7 and equations(4.13)–(4.14): developed reference-cylinder diagram distinguishes normal pitch, transverse pitch, axial pitch and one-turn lead. The corresponding KHK Technical Reference printed page is614.

SSG-R ground spur gear catalog: separate columns and dimensional symbols for face width E, hub width F and total length G.