Temperature influence on involute gear measurements

Abstract

Involute gears are high-stress components used in a variety of drivetrain applications. Small manufacturing tolerances require low measurement uncertainties in production metrology. A well-established traceability chain from industrial facilities to national gear measurement standards is essential for reliable quality control. Especially for large parts, the ambient and workpiece temperatures contribute to the measurement uncertainty considerably. However, measurements on the shop floor can rarely be performed at exactly 20 °C, which is the international reference temperature for dimensional metrology. In this paper, the influence of thermal expansion on gear deviations is discussed. Theoretical considerations are compared to results obtained via finite element analysis (FEA) as well as to experimental data. This also includes measurements of PTB’s large gear measurement standards under different temperature conditions. The outcome of this study can be used either to estimate measurement uncertainty contributors in industrial applications or to compensate thermally induced errors in gear measurements.