Applied Mechanics and Materials Vols. 215-216

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: Stress solutions are reviewed for some typical cases of axisymmetric and non-axisymmetric loads over a structural member with the principles of elasticity. A curved bar is chosen for the analysis. Tangential, radial and shear stress are determined analytically using Airy’s stress function. The curved bar is also modelled by finite element method to obtain numerical values of stress. Analytical and numerical results are in excellent agreement with each other.

Abstract: The aerodynamic characteristics have a great influence on the steering stability and the fuel economics of a high speed vehicle. The diffuser located at the aft part of a car underbody is one of the most important aerodynamic add-on devices. The parameters of the diffuser, including the diffuser angle, the number and the relative position of longitudinal separator (LS), the shape of the end plate and etc, will affect the underbody flow and the wake. Here, diffuser with longitudinal separator of different number and relative position was investigated. Numerical simulation was used to study the aerodynamic characteristics of a simplified sedan with different diffuser of longitudinal separator. The study found aerodynamic coefficient of the car changes little when we change the relative position of diffuser's longitudinal separator. Besides, we also found that increasing the number of the diffuser's longitudinal separator will increase the vehicle's aerodynamic drag coefficient and reduce the vehicle's lift coefficient.

Abstract: Cycloidal drives are widely used in today’s industries for drives where large reduction ratios are required. Drive-train dynamics plays an important role in their design. This paper presents a new methodology for assessing damping characteristics of Cycloidal drives and compares the natural frequencies obtained from experiments and theoretical/numerical calculations using Fast-Fourier-Transforms.

Abstract: Based on the mathematical model of non-linear rubber bearings under the condition of random excitation and time domain model of road roughness, the 11-dof vibrant model for vehicle was built with considering the non-linear rubber bearings. Then the influence of the rubber bearings on ride comfort was simulated under the condition on the B-class road profile by different speed as the random input. The result shows that the way of modeling the vibrant model is feasible, and the influence is not a simple monotone function, especially in the barycenter acceleration of vehicle body.

Abstract: How to reasonably design parameters for less-teeth gear transmission is a hard and significant work. In this paper, firstly, according to characteristics of less-teeth transmission, list a series of mathematical expressions. Secondly, edit the flow chart to edit program based on Matlab and design the man-machine interface, then got a group optimal parameters. Finally, use the optimal parameters to build 3D model of less-teeth gear.

Abstract: This paper takes a minivan’s manual transmission as the research object. The structure of the lock ring inertia synchronizer, the synchronizing principle and the test bench structure are introduced. After a series of tests, the test dates were analyzed and the results show that the test bench accord with the design requirements.

Abstract: This paper first establishes the graphic model and basic circuit equation of dual planetary gear transmission system based on modified complex joint picture representation method and basic circuit method. And then according to this model analyses the rotating relation and torque relation of dual planetary gear transmission system deduces the calculation formula of transmission rate efficiency. The sensitivity of each gear ratio to transmission efficiency is defined with the method of sensitivity analysis. By calculation and analysis, the influence degree of each gear ratio on transmission efficiency is obtained. The result can provide a basis for the design and optimization of dual planetary gear transmission system.

Abstract: The author describes tooth profile formatting mechanism of spherical involute spiral bevel gear based on Principles of Gear conjugate, establishes the mathematical model of spiral bevel gears. The precise spherical involute of spiral bevel gears is generated with parametric modeling idea and th secondary development method based on PROGRAM of PRO/E software. Finally, a complete spherical three-dimensional modeling of the involute spiral bevel gear is established, which provides a method of parametric design and manufacturing of spiral bevel gears.

Abstract: For the study of nonlinear dynamic characteristics of a pair of gears in an external torque under gear meshing error excitation, we will establish two degrees of freedom nonlinear torsional vibration model. The use of Matlab / Simulink for numerical simulation solves the nonlinear dynamic model of the gear gap. Study the dynamic characteristics of the system in a certain domain of parameters on external incentive conditions, as well as external motivation of gear transmission system dynamic characteristics influence. The results have important practical value for future engineering practice on gear transmission system's dynamic design, and have important theoretical significance for complex gear transmission system dynamics study.