The low-noise optimisation method for gearbox in consideration of operating conditions
This paper presents a comprehensive procedure to calculate the steady dynamic response and the noise radiation generated from a stepping-down gearbox. In this process, the dynamic model of the cylindrical gear transmission system is built with the consideration of the time-varying mesh stiffness, gear errors and bearing supporting, while the data of dynamic bearing force is obtained through solving the model. Furthermore, taking the data of bearing force as the excitation, the gearbox vibrations and noise radiation are calculated by numerical simulation, and then the time history of node dynamic response, noise spectrum and resonance frequency range of the gearbox are obtained. Finally, the gearbox panel acoustic contribution at the resonance frequency range is calculated. Based on the conclusions from the gearbox panel acoustic contribution analyses and the mode shapes, two gearbox stiffness improving plans have been studied. By contrastive analysis of gearbox noise radiation, the effectiveness of the improving plans is confirmed. This study has provided useful theoretical guideline to the gearbox design.
Vibration and noise analysis of a gear transmission system
This paper presents a comprehensive procedure to predict both the vibration and noise generated by a gear transmission system under normal operating conditions. The gearbox vibrations were obtained from both numerical simulation and experimental studies using a gear noise test rig. In addition, the noise generated by the gearbox vibrations was recorded during the experimental testing. A numerical method was used to develop linear relationships between the gearbox vibration and the generated noise. The hypercoherence function is introduced to correlate the nonlinear relationship between the fundamental noise frequency and its harmonics. A numerical procedure was developed using both the linear and nonlinear relationships generated from the experimental data to predict noise resulting from the gearbox vibrations. The application of this methodology is demonstrated by comparing the numerical and experimental results from the gear noise test rig.
A model for simulating the quasi-static and dynamic behaviour of solid wide-faced spur and helical gears
The classical formulations used for solving tooth load distributions in gear dynamics are critically assessed and an original model aimed at simulating the quasi-static and dynamic behaviour of solid wide-faced gears is proposed. Elastic couplings, also known as elastic convective effects, are introduced via shaft finite elements for gear body distortions and elastic foundations with time and position-varying properties for tooth deflections. Tooth shape deviations and alignment errors are considered, and solutions are sought by simultaneously solving the equations of motion and the contact problem between the teeth. The numerical results indicate that gear body distortions are critical for both static and dynamic simulations. However, tooth convective effects are generally of secondary importance but can become significant when contact extents are reduced because of shape deviations and/or mounting errors.