Papers by Keyword: Mesh Stiffness

Abstract: Gears in service conditions experience inevitable tooth damage. These damages can cause changes in the time-varying mesh stiffness depending on the mode of damage. The time-varying mesh stiffness of gears is an essential input in calculating gear dynamic responses. Several researchers have evaluated the mesh stiffness of gear teeth with single-mode damage like pitting, spalling, root cracks and wear using either or any combination of analytical, numeric and experimental models. However, limited research has been done on investigating the mesh stiffness of gear teeth undergoing multi-mode damage. In this work, an analytical model is proposed to evaluate the mesh stiffness of a tooth on the pinion with single-mode damage, including pitting, spalling, and surface crack, separately. In addition, a gear tooth with a combination of pits, spalling and surface cracks is also evaluated. The volume of damage on the tooth is kept constant to provide a basis for comparison. The comparison highlights the possible effects of the combined damage modes, which is a more realistic occurrence in gears in service.

Abstract: In this study, a mesh stiffness model of spur gear drives considering the tooth corrosion effect, which is based on Ishikawa model, is proposed. The fidelity of mesh stiffness based on the proposed model is checked by comparing the result with a benchmark result from the reference and the effect of the tooth corrosion on mesh stiffness is analyzed. The prediction indicates mesh stiffness is insensitive to the tooth corrosion, but this conclusion has a signification for assessing the stability of inherent properties of a spur gear drive when the tooth corrosion is produced.

Abstract: This study presents a dynamic model of helical gears for analyzing the effect of pinion-shaft flexibility on the dynamic behavior of helical gears. In the analysis, the time-varying mesh stiffness is determined in relation with the geometry of the gear pair and incorporates the deflection of the pinion–shaft. A comparison analysis is presented for the dynamic transmission error response of gear pairs supported with a rigid and a flexible shaft system. The results show that the pinion-shaft deflection must be included in the dynamic analysis since they can strongly affect the dynamic characteristics of helical gear pairs.

Abstract: In this paper, the object of study is one pair increasing gear with building a two-dimensional plane model in ANSYS. According to the gears meshing theory, considering the gear deformation, solve the static transmission error and the gear mesh stiffness in different conditions. The influence of the centre errors on static transmission error and mesh Stiffness are basis for modal analysis based on the mesh stiffness of gear and unbalanced harmonic response.

Abstract: The four ring-plate-type pin-cycloidal gear planetary drive is a new type of the cycloid. Use the new repair tooth profile gap mesh analysis method to Calculate the cycloid mesh stiffness. the mesh stiffness of the cycloid is solved, According to simulation results based on the ANSYS / LS-DYNA. and the results were compared with theoretical calculations, both mutual authentication. It can be use to improve the prototype program at last.

Abstract: A dynamic model of double-mesh helical gear set was established including the torsional vibration, axial vibration and time varying mesh stiffness. The natural modes were systematically analyzed and classified into three types: rotational vibration mode, axial vibration mode and overall vibration mode. The influence of time varying mesh stiffness and the dynamic responses of the gear set were also investigated. The results showed that several natural frequencies are excited in the dynamic response and there is a frequency sensitive area which may cause large dynamic load.

Abstract: Comprehensive meshing stiffness and single tooth meshing stiffness are calculated by tooth contact analysis and load tooth contact analysis program. The corner meshing impact model is proposed. Nonlinear dynamic model of helical gear transmission system is established in this paper considering time-varying meshing stiffness excitation, transmission error excitation, corner meshing impact excitation, and the backlash excitation. Take the ship’s helical gear transmission system as an example, the mesh impact force is derived and the primary factors that produce noises are discussed. The effects which the mesh impact brings to vibration characteristics of the gear dynamic system are concluded. Meshing impact has an inevitable effect on the vibration of the dynamic system. Impact excitation costs 8.5% in maximum of vibration acceleration response, 31% in maximum of instantaneous acceleration, and 4.9% in maximum of spectral component amplitude.

Abstract: Based on analyzing the defects of the usual equivalent conversion methods,the paper presents a new equivalent conversion method for mesh stiffness calculation of straight bevel gears of the small teeth number and diameter. By means of comparison among the different calculation methods,the conclusions can be obtained as follow:The straight bevel gear’s mesh stiffness value calculated by the new equivalent conversion method and Yishikawa formulae improved is more enhanced obviously than one calculated by the usual equivalent conversion methods and Yishikawa formulae ,and its change trend is closer to the numerical calculation value than the change trend of the straight bevel gear’s mesh stiffness value calculated by the usual equivalent conversion methods and Yishikawa formulae.

Abstract: The common definition of vibration influence chart is proposed in this study. A 46 degree-of-freedom time-varying dynamic model with coupled translation-rotation effect is developed to simulate the vibration of an encased differential planetary gear system using lumped mass method. With the dynamic load and the acceleration on gears and bearings as references, the dynamic responses in different load cases are investigated to search the change law of concerned parameters. The parameters considered include mesh stiffness, structure stiffness, gear mass and moment of inertia. The good and poor regions for vibration are evidently presented in figures, which is convenient to conduct the parameters design of planetary gear systems.

Abstract: Time- varying mesh stiffness and sliding friction between teeth are the great excitation for vibration and noise in gears system. But, there are rarely studies on this topic. This paper proposes a new dynamic modeling of gear system, which is effect of mesh stiffness variation, sliding friction and distribution of load. Firstly, the expression of time-varying mesh stiffness is gained, which is a period function. Secondly, a new friction modeling has the same period as mesh stiffness, is proposed. Thirdly, friction torque of each gear pair is calculated respectively, which is considering the distribution of load and time-varying friction arm. Finally, because all parameter have the same cycle, it is easy to get the approximate analytical solution to non-line model of gear dynamic by fourier transform.