Influence of Micro Geometry Modification on Gear Dynamics

2022

Vibration

Increasing torque and power density in geared transmissions is a constant trend, especially due to the electrification and the research of higher efficiency. Thinner web of the gears has led to potentially higher vibration amplitudes and noise levels, which need to be accounted for in the design stage to avoid fatigue or NVH problems. In the present paper a novel model to represent the dynamic interaction in geared transmissions is presented. The compliances of the shafts are taken into account in two different ways: in a simple strategy, by means of three-dimensional beam elements; in a more detailed methodology, by reduction in a FE model of the gear and shaft assembly. The different gears are connected using kinematic relationships exploited by means of rigid joints and rigid body elements. The flexibility of the teeth and of the gear body is introduced based on an established nonlinear calculation model and is employed as the only dynamic excitation source as a time varying mesh stiffness. Thanks to the reduced size of the matrices a direct integration scheme is used for the time domain analysis of the transmission. Such methodology enables the possibility of modeling dynamic contact loss and torque variations at different rotational velocities with reduced computational times in comparison to other approaches. The technique is then applied to two different geometries of driven gear: one with solid web and one with flexible web. The dynamic behavior of the two different solutions is studied and the differences are highlighted. The proposed approach proves to be more efficient than traditional multibody analyses and quicker than finite element approaches, while maintaining a similar accuracy. It proves to be effective also for studying the transmission with flexible web.

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Section: Introductionmentioning

confidence: 93%

Effect of Web Flexibility in Gear Engagement: A Proposal of Analysis Strategy

2022

Vibration

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“…Some focus has also been shifted to the predesign phase of the engineering process to design a gearbox by introducing quicker, yet reliable, results for example using a block-oriented approach as in [157] or with the application of the harmonic balance method in [158]. In this context an efficient method with a 3D Non-Hertzian contact model has also been proposed ( [159]) and applied for different profile modifications in [160] also detailing the effects of torque inversion during operation. More than one hundred years demonstrate that the study of gear dynamics is still a challenge and an interesting field of investigation.…”

Section: Future Perspectives and Conclusionmentioning

confidence: 99%

Sources of Excitation and Models for Cylindrical Gear Dynamics: A Review

2020

Machines

Self Cite

In this paper, a review of the evolution of the study of cylindrical gear dynamics is presented. After a brief historical introduction to the field, the first attempts to describe the complex interactions in those systems are analyzed introducing the dynamic factor and the first methodologies used to compute it. Next, the sources of excitation in geared systems are analyzed in detail and the models of the various contributions are discussed. Then, the paper focuses on the use of those sources in several dynamic models which are wildly different in terms of scope, applicability, complexity and methodology employed, ranging from simple analytical models, to lumped masses models up to multibody and finite element models. Finally, an outlook to the future evolution of the field is given and conclusions are drawn.

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On the Influence of the Actual Load Sharing Factor in Increasing the Power Density in Gearboxes

Mechanisms and Machine Science

2023