Previous thermal studies on planetary roller screw mechanism (PRSM) are mainly concentrated on frictional heat without the consideration of external thermal loads. However, the contact behavior of planetary roller screw mechanism varies greatly during the operation process. In this paper, a calculating method for frictional heat of planetary roller screw mechanism based on friction torque is proposed, and a transient thermal model is established to analyze the heat transfer of planetary roller screw mechanism at multiple thermal conditions. Then, an analytical method is introduced to investigate the temperature and the equations of its influences on the thermal deformation are derived. The influences of temperature distribution on the clearances and contact positions of the mating thread surfaces is studied as well. We found that the frictional heat, thermal resistance and thermal loads can significantly alter the temperature distribution consistency. The results indicate that the load-bearing capacity of planetary roller screw mechanism is greatly affected by the temperature differences between the planetary roller screw components. By allowing comprehensive thermal simulation, the proposed model can be utilized for PRSM optimization design.
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<p>The powder metallurgy database is a data system for effective management of powder metallurgy information. With the development of information technology, its construction scale and quality will directly affect the convenient inquiry of powder metallurgy information, the selection of gear materials, the research and development and engineering application of micro-drive systems, and have engineering significance and market value. However, the groundwork in this field still lags behind other materials fields and needs to be developed systematically.</p>
<p>Consider the small modulus powder metallurgy gear's elastic modulus, Poisson's ratio, fatigue life, metallographic structure and processing parameters as research objectives, the functional requirements of the database, system functions and data relationships are analyzed. The function module, database model, user authority and system architecture are designed in detail. Based on the Flask framework and MySQL, the database system on the basic properties of powder metallurgy materials is designed and developed, which realizes the systematic and standardization of mechanical property data of powder metallurgy. Users are provided with upload, query and retrieval services of chemical composition, heat treatment and molding properties, fracture mechanics, material suppliers and other information.</p>
<p>In this paper, the necessity and urgency of building a powder metallurgy database to increase the efficiency of transmission system development and its application are demonstrated. The deficiencies of the existing powder metallurgy database are analyzed, and suggestions are provided for the selection, design, data coverage, and construction of big data applications for smart materials. The technical challenges of small modulus powder metallurgy gear selection and plan formulation are then ameliorated.</p>
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<p>Github repository: <a href="https://github.com/haomjc/PMdatabase2" target="_blank">PMdatabase2 (github.com)</a> </p>
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