Gear Wheel Contact Pattern Analysis

Thousands of revolutions in continuous operation – a gear wheel is exposed to considerable wear. Accurately manufactured gear wheels with an even transmission behaviour and ideal contact pattern are quieter and have a longer useful life.

To check the contact pattern (i.e. the areas where the gear wheel surfaces touch), gear wheels used to be coated with paste and inspected on a test bed. The locally differing wear of the paste produces the contact patterns. The reliability of this method depends, however, on the experience of the tester and is very difficult to automate (reflecting surfaces).

Measuring the frictional heat now enables contact-free inspection of tooth face precision. Load transmission between tooth faces generates frictional heat that varies depending on the pressure distribution. The contact pattern can be determined separately for each pair of tooth faces by thermal imaging immediately after tooth contact.

The particular challenge facing the thermal imaging system: the high rotation speed calls for an extremely fast line camera. The method places the highest demands on IR recording and numerical evaluation of the measurement data.