Characteristic Analysis, Experiment And Application Study Of Nuvinci CVT

With the development of industry and modern technology, mechanical CVT has anincreasing extensive application because it is simple in structure and smooth in transmission,reliable in work. Meanwhile each production field has a higher requirements in CVT. Based onthe premise of meeting the request of working, it has been a research trend in both domestic andoverseas to make transmission ratio range bigger and make speed regulating more convenientand quick. According to the complex regulating process in current seeding and planting machinein rice field and difficulty control in regulating quantity, after researching and analysing themechanical properties of NuVinci CVT, this paper puts forward a quantity-regulating plan basedon mechanical CVT transmission, and a virtual prototype simulation has been carried out.The main research contents and conclusions are as follows:1) The kinematic and dynamic analysis of variable speed mechanism of NuVinci CVT areconducted. Through establishing mathematical model, analyze and research the relationshipbetween its structural parameters and material properties such as transmission ratio, gear ratio,load torque, slip rate, transmission efficiency etc. And using the MATLAB software, achievethree-dimensional surface chart of the impact of structural parameters and material properties onthe mechanical properties, and lay the foundation for the selection of structural parameters ofNuVinci CVT.2) The regulating mechanism of NuVinci CVT is analyzed. For sheaves profile design,propose a reverse design method of sheaves profile based on the output characteristic curve ofCVT. And according to the design requirements of seeder, make an example of design.3) Parametric transfiguration of the NuVinci CVT has been designed based on VB.net andUG,which lay a foundation of the parameterization and serialization of the NuVinci CVT.4) Virtual prototype simulation experiment has been conducted for NuVinci CVT byADAMS Simulation software; to analysis kinematics simulation according to different speedconditions and load or not.5) Develop the CVT experimental platform, experimental study the mechanical property of the transmission efficiency changing with the load and speed in different transmission ratio;experiment result shows: The transmission efficiency of CVT changes with transmission ratio;and reaches the maximum in equal speed transmission；When choose R0=15mm, Rc=20mm asstructure parameters, the maximum load torque is15N.m，further verify the correctness oftheoretical analysis.6) Based on the previous research and analysis, an improved proposal based on Free-BallCVT is put forward; and using UG software, the virtual prototype is assembled. Through thecomparative analysis of the existing seeder and CVT schemes，the results indicate that the CVTscheme can not only simplifies the structure and procedures on regulating quantity in a largeextent,but also greatly improves the continuity and uniformity of sowing density, so thatagricultural demands of different sowing density are better satisfied.