Research On Tooth Profile Modification And Noise Analysis Of Elliptical Cycloid Rotor Oil Pump

In the course of operation,the oil pimp will have different levels of vibration and noise due to various reasons,mainly with fluid noise and mechanical noise.As the engine oil pump is one of the important parts of the automobile engine,its radiation noise seriously affects the overall level of the automobile engine noise,so the research of the noise of the pump is particularly important.In this paper,an elliptic cycloid rotor pump is provided for a certain oil pump company in Hunan,the virtual prototype model of the pump was established firstly,using Spline interpolation of internal and external rotor torque to calculate the inner and outer rotor meshing contact time series dynamic contact force,so as to further solve the pump body and the pump cover vibration displacement due to dynamic contact force,and then solve the mechanical noise.Three dimensional software is used to extract the flow passage of the oil pump,and then the flow field data in the operation of the pump is solved by using a professional pump CFD analysis software Pumplinx,by modifying the case file in the acoustic simulation software to solve the fluid noise,then the sound source superposition and experimental verification,finally to provide the rotor oil pump design a kind of tooth profile and the ellipse the tooth profile modification scheme comparison analysis.The research work of this paper is as follows:(1)According to the analysis of internal and external rotor sliding of cycloid rotor pump rate,pointed out that a complete cycle of operation,causes the inner and outer rotor tooth profile meshing section of meshing impact will occur several times,with the principle of vibration acoustic radiation of structures that vibration under load will produce acoustic radiation and acoustic wave will cause structural vibration.Then,the exciting force and the vibration displacement of the pump body and the pump cover are solved,and the mechanical vibration radiation noise of the oil pump is simulated.(2)Pump flow passage is extracted,and flow field data is solved based on professional valve CFD software Pumplinx.By modifying the Case file,using the flow data as the boundary condition in the further acoustic simulation calculation software to simulate the fluid noise,then mechanical noise and fluid noise are superimposed and verified by experiment.(3)Designing a new kind of similar elliptic rotor tooth profile,including the inner rotor and outer rotor meshing with each other,the outer rotor contains one more number of teeth than inner rotor.The half of every tooth profile of the outer rotor is composed of a section of similar elliptic arc,a tooth bottom arc and arc chamfer touching with the similar elliptic and tooth bottom arc at the same time.The ellipse rate of exterior elliptic arc increases with square root of tooth profile angle.The tooth profile of each tooth of the inner rotor is a conjugate curve of the elliptical section tooth profile of the outer rotor,each pair of teeth inside and outside the rotor is engaged in meshing during meshing.At the same time,the flow performance analysis,liquid moment analysis and multibody dynamics analysis are compared with elliptic profile and similar elliptic profile.Application of oil pump with similar elliptical can reduce the cost of modification without changing the original design of the pimp body.lt also can reduce the maximum value of tooth profile slip rate at meshing boundary point and torque generated by oil on inner rotor on the basis of improving the oil pump flow at low speed.At a result the similar elliptic improve the rotor pimp flow performance and reduce barase and save energy.