Cylindrical Gear Metrology

Abstract

This chapter presents the basic principles and techniques for measuring the geometrical features of cylindrical gears. The mathematical models for nominal cylindrical gear geometry are given in a two-dimensional (2D) space and extended to a three-dimensional (3D) space. The geometric parameters for assessing the conformance of gear design and manufacturing are highlighted based on the current international standards. Conventional gear inspections by tactile measuring systems such as gear-measuring instruments (GMIs) and coordinate measuring machines (CMMs) are discussed in detail, including measuring strategies and evaluations of “raw” spatial data sets, methods of calibrating gearmeasuring systems, and the estimation of measurement uncertainty. Emerging technologies including optical measuring systems and areal evaluation methods are introduced as part of future cylindrical gear metrology.