Workpiece hardness measurement system for bolt holding planet wheel in epicyclic gear has multi frequency eddy current measuring coils passed along length of bolt to detect soft ends

摘要

The bolt (1) used to hold a planet wheel in an epicyclic gear train has a hardened center section (2) and soft ends (3). The workpiece hardness measurement system uses a multi-frequency eddy current measuring coil (4) which is passed along length of the bolt. Differences in the eddy currents enable it to detect and measure the lengths (b) of the soft ends of the bolt.