| Dry scroll vacuum pump(DSVP)has been widely used in many industries with its inherent advantages of outstanding pumping capacity,low power consumption,low vibration and noise and oil free performance in the cavity,resulting in the increasing demand for DSVP.The huge fund have been invested to study DSVP by many research institutes and vacuum equipment manufacturers at home and abroad.However,it is difficult to improve the performance of the scroll vacuum dry pump,which has a limited role in application of DSVP.This paper aims to improve the performance of scroll vacuum dry pump,and widen the scope of application of scroll vacuum dry pump,to provide efficient and clean vacuum environment for more industrial areas.In this paper,the multi-cavity dry scroll vacuum pump(MCDSVP)was researched in detail.According to the mechanical theory of scroll,the calculation method of MCDSVP was put forward and established,and then compared with the single cavity structure.It was found that the suction speed of multi-chamber was increased by 76.4%,the peak load of bearing is reduced by 88.8%and the friction loss is reduced by 58.3%compared with that of single chamber under the same comparison standard,which proved the design superiority the theory of MCDSVP.Then taking the four-chamber as an example,the steady-state deformation and stress of the four-chamber dynamic and fixed scroll with gas load,thermal load and multi-field coupling were studied respectively with ANSYS Workbench.Through the thermo-mechanical coupling analysis of the multi-cavity vacuum pump under the condition of assembly,the optimal radial clearance of each scroll body is 0.06mm in the four-chamber scroll vortex pump,which provide theoretical guidance for the design and study of the bilateral scroll vacuum pump.Next the improvement measures of seal method in MCDSVP was put forward.First the correlation between the supporting structure and the sealing mode of the DSVP were explored.Then the application of bellows seal technology and the existing problems of scroll vacuum pump was analyzed.The application of bellows in the scroll vacuum pump was developed and it was applied to the bilateral scroll vacuum pump.By the finite element analysis of simple support and cantilever,it was found that the maximum of spindle deformation and stress only increases by 0.73μm and 9.4MPa,which was still within the permissible range under the cantilever support and found that the four-chamber vortex cantilever extension length was 45mm.It is the basis for improvement of support structure and seal form of MCDSVP.Finally,the manufacturing method of multi-cavities scroll was discussed.Three feasible scroll manufacturing methods were introduced,and the most common numerical control machining method was selected.With UG CAM module,it was found that the working time of the multi-chamber scroll was only 12.1%longer than that of the single chamber in the condition of fine castings,and the use of the existing equipment can fully realize the equivalent machining.According to the characteristics of multi-cavities scroll work,the design and processing precision guaranteed of multi-chamber scroll was put forward.In order to ensure the proposed machining requirements,a special designed fixture has been designed... |
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