| A pair of gear rotors that mesh with each other play an important role in determining the working performance of the gear pump.The end profile of the gear rotor is the basis of the design of the gear rotor and has a great impact on the running performance of the gear pump.In order to construct new types of gear rotor with no trapped fluid and more flexible design,in this paper,the author established a meshing model of the higher-order curve and its envelope under the double-rotational motion based on the plane curve meshing theory and the gear meshing theory,and deduced suitable curves for the construction of gear rotors.The envelope equations of the circular arc and elliptic arc,and then two new types of gear rotors without trapped liquid,an arc-high-order curve gear rotor and an elliptic arc-high-order curve gear rotor are proposed.The parametric equations of the end profiles of the new gear rotors are derived.Three-dimensional numerical simulations of the working process of two new types of high-order curve gear rotors are carried out,and the internal flow characteristics of their working chambers are studied.The distribution rules of their pressure fields and velocity fields are analyzed,and they are compared with the existing involute gear rotors.The distribution of stress and deformation of two new types of gear rotors under the combined action of temperature and pressure loads are studied.Taking the arc-high-order curve gear rotor as research object,the coincidence condition of the gear rotor without trapped liquid and continuous transmission is analyzed,and its displacement and flow rate are calculated.The radial force,axial force and torque of the new gear pump in the working process are studied.The volume utilization rates of two new high-order curve gear pump rotors are studied and calculated.The research results show that the proposed arc-high-order curve gear rotors avoid liquid trapping during the working process,reduces the flow pressure pulsation,and effectively improve the working performance of the gear pump.The proposed elliptical arc-high-order curve gear rotor has the advantages of high volume utilization and good meshing performance.Through the analysis and calculation of the two new high-order curve gear pumps,it is found that the flow rate of the elliptical arc-high-order curve gear rotor is large and the volume utilization rate is high,and the flow and pressure pulsation of the elliptical arc-high-order curve gear rotor is also smaller than that of the arc-high-order curve gear rotor.Through the analysis of the force and deformation of the two new high-order curve gear rotors,it can be seen that the force deformation of the gear rotor is mainly affected by the pressure loads.Under different meshing angles,the maximum deformation is mainly located at the tooth tops of the rotors on both sides of the gear pump.The proposed two new types of high-order curve gear rotors have good design flexibility and can be adjusted to meet the needs of different working conditions through performance parameter adjustment.The research contents of this article are of great significance for optimizing the gear rotor and promoting the development of gear pumps. |
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