The Dynamics Simulation And Finite Element Analysis Of The Row-Spacing Gearbox Of Rice Transplanter

Row-spacing gearbox is one of the important powertrains of rice transplanter, which is the hub of power transmitting between and planting system, and is the core of the control planting spacing. Gear transmission system as the core power transmission device of the row-spacing gearbox, the dynamic behavior have a vital influence on the whole gearbox. Therefore, row-spacing gearbox gear transmission system dynamics simulation analysis has great significance, because it can provide the corresponding basis for spacing gearbox design optimization and fault diagnosis.In this paper, taking row-spacing gearbox of the school-enterprise cooperation project (The research and development of high-speed rice transplanter) for the study, according to the gear system dynamics theory, multi-body system dynamics theory, the collision contact theory and finite element theory, dynamics simulation and finite element analysis of the row-spacing gearbox are carried out based on virtual prototyping technology by using UG, ADAMS and ANSYS Workbench softwares. Main work and conclusions of this paper are as follows:(1) In accordance with the technical requirements, the structure of the row-spacing gearbox is designed, the basic parameters of all gears are determined, and the kinematic and dynamic parameters of the spacing gearbox transmission system are calculated for providing reference of the simulation result.(2) The virtual prototype model of row-spacing gearbox is set up by using UG and ADAMS softwares, the dynamics simulation analysis on row-spacing gearbox is implemented and the time domain curve of different gears meshing force is obtained. The results show that the meshing force change law of the constant transmission ratio gear is largely the same, meshing force fluctuate around a certain value, the gear with minimum coincidence degree has the biggest meshing force fluctuation; the meshing force of elliptic gear display periodic fluctuation around its static curve in a certain range, and with the elliptical gear transmission ratio increases, the meshing force fluctuation amplitude increases. Taking a pair of input gear as an example, the meshing force spectrum is analyzed. Analysis shows that the gear in addition to engage the fundamental frequency of vibration, also have a high frequency vibration of2to7times, and there exits a larger vibration and noise.(3) Finite element analysis of gear bending and contact stresses are implemented by using ANSYS Workbench software with the static load and the maximum impact load as loading conditions. Analysis shows that the maximum bending stress and the maximum contact stress of gear under the maximum impact load are2.01times and1.63times of the static load, and the gear satisfy the intensity requirement.(4) Do some research on the change law of the gear meshing force amplitude, the maximum bending stress and the maximum contact stress under different speed, studies have shown that as the speed increases, the gear meshing force amplitude, the maximum bending stress and the maximum contact stress are approximately linear increases gradually. When the speed reaches1400rpm, the maximum contact stress exceeds the limit of the contact fatigue strength, the tooth exist premature risk of fatigue damage.(5) Provide the modal analysis of the row-spacing gearbox hulls with ANSYS Workbench software, then compared with the maximum frequency of gear meshing. The result shows that the first order natural frequency of the row-spacing gearbox hulls is far less than the maximum frequency of gear meshing, and the material choice and the structural design of the row-spacing gearbox hulls is appropriate.