For the beveloid gears with intersecting axis and crossed axis coexisted in the marine gearbox with small down angle, contact analysis of the meshing gear pair taken the assembly error into consideration is proposed based on the nonlinear finite element analysis software Abaqus. Considering the central distance error, axial position error and the angle error, the FE model of beveloid gear pair with intersecting axis and crossed axis were established, respectively, and the tooth contact stress, the maximum influence factor and transmission error were calculated. The effects of these errors, the central distance error, axial position error and the angle error on the contact characteristic were discussed.
Several modals on Tunnel Boring Machine (TBM) in tunneling are introduced, the revolving rock tunneling simulator set-up is designed, the finite element model of cutter parts of the experimental bench is built, and free mode analysis of it is performed, and the model on system of cutter head, cutter and rock is established. It is shown that natural frequency on the cutter parts is higher, the frequency of first step is 4536Hz, and the most modes are deformations of the cutter loop, vibration acceleration of the cutter decreases with fracture tunnel width increasing, in some degree broken rock mechanics is achieved, foundation is provided for improving using life and adaptability of the cutter, and optimizing arrangement of plate cutter on the cutter head, and finally realizing high efficiency and low energy consumption.
Structure parameters of muffler element with inserted tube are firstly determined, it is analyzed to the inserted length effecting on sound power of flow regeneration noise and frequency characteristic, and distribution feature of flow velocity and turbulence kinetic energy is explored by numerical computation of flow field. It is shown that flow regeneration noise of muffler element with inserted tube forms according to confined incomplete flow-inject, it presents wide frequency band, and its energy focus on middle and low frequency, especially it is about 600Hz, Strouhal Number is 0.5. When its structure parameters is constant, distribution feature of flow velocity and turbulence kinetic energy doesn’t change with flow velocity, and difference is numerical dimension, and turbulence kinetic energy distributes near inserted tube in wall, this is area occurring flow regeneration noise, so producing mechanism of flow regeneration noise from muffler element with inserted tube is achieved.
Improving design of some automotive muffler is introduced, according to the existing problem of original exhaust muffler in is modified, using sound software attenuation characteristic is analyzed, and pressure distribution of muffler inner is performed to calculate adopting three-dimension flow field tool, and the muffler is tested on engine bench. Result shows that Compared with the original muffler, power loss is decreased by about 30%, set-net noise of the original muffler all has dropped dramatically, and it is in the target.
Due to the difficulty in large gear modification, a method that modifying gear tooth in the processing through correcting gear cutter was proposed. In this paper, modification theory of large gear and design method of gear cutter were introduced in detail. Based on gear meshing theory, the tooth equation of large gear was deduced from the equation of correcting cutter. The processing was simulated by using Matlab software, and it verified the validity of theoretical analysis.
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