A gear contact pattern is the observed region of tooth-flank contact during a stated mesh test. Its position and extent reveal how the installed tooth surfaces meet. A gear contact marking test uses a thin marking layer and controlled rotation to make that region visible; the mounting position, transmission direction and applied torque belong in the test description. Manufacturer guidance treats surface-contact checks as evidence about the assembled mesh, including shaft alignment.[ref]
A useful bench comparison holds the gear pair and test conditions fixed, records the initial mark, then changes one alignment setting and repeats the test. A mark moving toward one face edge indicates a change in where the flanks meet. This is an observation of contact location, rather than an automatic measurement of operating pressure or a universal diagnosis of the alignment error.
For example, a mark occupying the full20mm gear effective face width is compatible with a hypothetical uniform line load , but also with the tilted positive distributionBoth integrate to1000N, yet their peak line loads are50 and80N/mm. Merely observing full-width contact cannot choose between those gear face load distributions. The gear face load factor or local stress needs additional load/deformation information.
Loaded and lightly loaded patterns can also differ because shaft, housing and tooth deformation change the gap. A quantitative loaded assessment may use strain measurements or a validated contact model alongside the pattern; the2006 gear-rating standard explicitly distinguishes comprehensive load assessment from the limited information in a bearing pattern.[ref]
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