| In recent years, the development of photoacoustic imaging technology has become a new type of biological medical image technology, which has the nondestructive, high resolution, especially for the early detection of tumors. Dr Songliang, from Shenzhen institute of advanced technology, Chinese academy of sciences, has led the research team to set up multiple sets of photoacoustic imaging system in the domestic leading position.Transducer and laser probe need to make a rotation around the measured object in order to obtain different position of photoacoustic signal in the single circular scanning probe photoacoustic imaging system. While the rotation movement of the transducer and the laser probe is controlled by the motor, the motor output shaft between the transducer and the transmission structure is very important. Because the power transmission in the process of vibration will affect the quality of photoacoustic signal acquisition. Therefore, it is necessary to research and analyze the structure of the transmission system. Considering the transmission stability requirements, we choose way of worm drive.In this paper,we the take Archimedes worm based on circular scanning photoacoustic imaging as the research object,and set up threedimensional entity model.Using the finite element analysis software ANSYS Workbench to analyze surface contact in the process of worm drive. Space curved surface contact analysis generally is difficult to analyze, which involves the friction, contact state, etc. This paper detailedly describes the basic steps of contact analysis, the generation of meshing process, the definition of constraint and load applied way of worm and gear.1. Introduce the Archimedes worm and gear tooth surface equation and the mathematical model of mathematical expression and the worm gear tooth surface on both sides, as the theory foundation of Archimedes worm drive model is set up accordingly.2. Because of the worm and gear surface shape is more complex, high precision machining requirements, emphatically discusses the ZA worm and gear tooth as well as the modeling method, the mathematical model using Solid Works entity modeling method of 3-D modeling of worm gear and worm, and the assembly simulation.3. Describes the common 3-D model analysis methods and theory based on the ANSYS Workbench software. Using statics theory to analyze the contact problem of ZA worm drive, postprocessing, the solution, finishing process, the resulting stress on the surface of the worm gear and worm in contact.4. Compare the contact stress theoretical calculation results with the actual situation of the finite element analysis, we can get the results that both contact stress value have little difference, shows that the finite element method analysis of contact stress between worm gear and worm was more accurate. Analysis of the two common installation error, respectively of the two installation error cases to compare the size of the contact stress analysis. The results show that when the installation error, the greater the tooth surface, the greater the stress value is bear the greater the load, reduce the service life of worm and gear. It’s consistent with the reality.5. For solid modeling, modeling parameters of the specific basis of does not give but by experience to determine the model parameters. So, still need to optimized design of worm drive mechanism, in order to design parameters as optimization variables, the minimum volumes of worm gear as the optimization objective, considering the worm drive gear teeth, modulus constraints worm, worm diameter coefficient, stiffness constraint conditions, such as using numerical analysis software MATLAB optimization toolbox of worm drive mechanism to optimize multiobjective constraint minimum and ultimately determine the optimization scheme. Save the design materials, improve the quality of the worm drive. |
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