AGMA 16FTM15 PDF

Ground bevel and hypoid gears have a designed motion error that defines parts of their NVH-behavior. Besides others, the surface structure has an effect on the excitation behavior. This surface structure is defined by the hard finishing process. Grinding shows the advantage of high repeatability, defined flank forms with closed-loop corrections, and subsequently very low reject rates. However, it is known that for example lapped gearsets show, at least at low loads, a lower excitation level, including the lower as well as the higher mesh harmonics. The generation of a ground pinion is realized with a generating motion of a cup-shaped grinding wheel that follows a path given by the axis position table. Machine motions itself in combination with resulting machine vibrations, and imperfect grinding wheel roundness during a standard grinding process can lead to a distinct surface structure with facets parallel to the contacting lines. These lines, including their waviness, are crossed while the contacting zone passes along the path of contact and lead to excitations when rolling the bevel gearset. The MicroPulse-process [1, 2], as it is implemented at present, gives the possibility to influence each axis position in each line of the axis position table with small predetermined or random amounts. The presented development is a process which improves the excitation behavior of a ground bevel gearset by altering the surface structure of a generated member along the path of contact from slot to slot. This process can include the use of the MicroPulse motions, but it can also be applied without MicroPulse. Instead of using the same axis-position-table for every ground slot, which is the state of the art, every slot receives changes to its specific axis-position-table. The changes from slot to slot are calculated to address the objectionable harmonic excitation. For this reason, the objected harmonic excitation is predictably addressable based on a closed-loop iteration calibrating the chosen process parameters.