| The paper comes from the national project of low-temperature pressing technology and equipment research,and studies the theory of screw press.By using modern scientific methods such as mathematical modeling.numerical analysis and finite element analysis,the key parts of the press section of the oil press are analyzed,and new concepts such as compression ratio distribution and snail dynamic configuration are put forward.The following are the main contents of this paper:(1)The working principle of the screw press is briefly described,the development status of the screw press in China and abroad is investigated,and its future development direction is prospected.(2)The structure of squeezing cage and screw shaft in screw oil press is analyzed,and the concept of compression ratio is introduced for the follow-up study.Several different models of spare volume are modeled mathematically.Finally,the spare volume is calculated automatically by VB programming software,which lays a foundation for the further study of compression ratio.(3)The distribution of compression ratio is studied more deeply.The geometric parameters of six main kinds of screw press in market are sorted out,and the approximate basic mathematical model is obtained by analyzing the compression ratio at all levels through software.The compression ratio of different oils is studied.According to the common problems in the actual production of enterprises,the concept of dynamic assembly of screw axles is put forward,which can help the design of screw press in the future.Finally,the squeezing model is discretized into hexahedral micro-elements,and the hydrostatic equation is used to analyze and calculate the pressure formation and its change process.(4)Experiments were carried out on the scheme after the dynamic combination of the front snails and the finite element analysis of the pressing part was carried out.The shape variables and stress conditions of the key parts of the press are studied,the structural strength is checked,and the maximum stress distribution law is summarized.Suggestions are put forward for the design of the press in the future.At the same time,the relationship between the fillet size and the stress of the screw is summarized,which provides a reference for the design of the fillet size.A foundation for the further study of the screw shaft design and the compression ratio distribution theory has been put out in this paper,and the writer provides a new idea for the design of the screw shaft dynamic assembly system in the future. |
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