Grinding of bevel and hypoid gears creates on the surface a roughness structure with lines that are parallel to the root. Imperfections of those lines often repeat on preceding teeth, leading to a magnification of the amplitudes above the tooth mesh frequency and their higher harmonics. This phenomenon is known in grinding and has led in many cylindrical gear applications to an additional finishing operation (honing). Until now, in bevel and hypoid gear grinding, a short time lapping of pinion and gear after the grinding operation, is the only possibility to change the surface structure from the strongly root line oriented roughness lines to a diffuse structure.
In the design process of transmissions, one major criterion is the
resulting noise emission of the powertrain due to gear excitation.
Within the past years, much investigation has shown that the
noise emission can be attributed to quasi-static transmission error.
Therefore, the transmission error can be used for a tooth contact
analysis in the design process, as well as a characteristic value for
quality assurance by experimental inspections.