Reduction of the tonality of gear noise by application of topography scattering

Abstract

In the design process of transmissions, one major criterion is the resulting noise emission of the powertrain due to the gear excitation. Within the past years, a lot of investigations have shown that the noise emission can be correlated to the quasi-static transmission error. Therefore, the transmission error can be used as a characteristic value for quality assurance by conducting experimental inspections as well as a tooth contact analysis in the design process.An optimization approach to solve gear whine issues is the reduction of the gear mesh excitation. In this report, a novel optimization approach for gears is presented. A targeted topography scatter from tooth to tooth is applied on the teeth of the gear set, in order to manipulate the composition of the gear mesh excitation. As a result of the slight deviations for each tooth mesh, the regularity of the transmission error excitation is broken up leading to a reduction of the tonality of the resulting gear whine.In the first step, different topography scatter variants are calculated in the tooth contact analysis. Based on the transmission error spectra, two variants with a topography scatter are chosen for manufacturing. The evaluation of the predicted excitation behavior is evaluated on a conventional bevel gear tester by means of single flank tests. A test fixture for the evaluation of the operational behavior under loaded and dynamic conditions is used to compare the measured and simulated dynamic excitation behavior. In order to simulate the dynamic behavior, a torsional multi-body-simulation model of the powertrain is developed that uses the stiffness of the gear mesh calculated by the tooth contact analysis as input data for the excitation forces. The force-coupling-element connects the drive and the driven train and forms the excitation of the gearing.Finally, it is the aim to evaluate the impact of the targeted topography scatter psychoacoustic parameters, such as loudness, sharpness, roughness and tonality. The potentials of the topography deviation for the optimization of ground bevel gears in terms of tonality reduction will be shown by means dynamic test rig trials.