Research On Contact Impact Model And Time-varying Meshing Stiffness Of Radial Flexible Scroll Compressor

Scroll compressor is a positive displacement compressor,which is widely used in air conditioning,refrigeration and gas compression for its advantages of high efficiency,low noise and good stability.However,in the process of processing and assembly of scroll compressor,due to the existence of various error factors,the gap between the dynamic and static scroll teeth at the meshing point is too large or over squeeze each other,resulting in gas leakage between the compression chamber or serious wear of scroll body,and also affect the performance of scroll compressor.In addition,as the internal parameter excitation of scroll compressor,the time-varying stiffness excitation is one of the main factors that cause the vibration of scroll compressor in the process of high-speed operation,which affects the dynamic characteristics of the system.Therefore,it is necessary to conduct in-depth research on the dynamic and static scroll contact impact model and time-varying mesh stiffness.The main research contents and conclusions of this paper are as follows:(1)Based on the geometry theory,mechanical properties and leakage model of scroll disk,the meshing impact model of scroll teeth in radial flexible scroll compressor was established.In order to solve the leakage problem between dynamic and static scroll teeth caused by meshing errors in radial flexible scroll compressors,the concept of dynamic and dynamic scroll teeth meshing impact was proposed based on the contact dynamics theory and the meshing principle of dynamic and dynamic scroll teeth,and the meshing contact impact dynamics model of scroll compressors was established.The finite element method was used to calculate the deformation of the model at the meshing point.The results show that the deformation of the scroll teeth increases with the increase of the spindle Angle under the meshing impact excitation in a compression cycle.This conclusion will lay a foundation for the dynamics modeling of the scroll compressor system.(2)The contact collision model of radial clearance of rotor and stator vortex teeth is established.Based on the L-N nonlinear spring damping impact force model,a contact impact model of radial clearance of rotor and stator vortex teeth considering meshing error excitation was established.matlab was used to calculate the deformation at the meshing point.The results show that the deformation at the meshing point is consistent with the deformation trend under the meshing contact impact model.The collision recovery coefficient in the model also has a certain effect on the deformation at the meshing point.Therefore,the initial clearance of mesh point can be determined by controlling the collision recovery coefficient,and a new idea can be provided for controlling radial leakage of scroll compressor.(3)Calculate the time-varying mesh stiffness of involute scroll teeth in scroll compressor.According to vibration theory,the physical model and mathematical model of meshing stiffness of scroll teeth are established and the calculation method of time varying meshing stiffness of scroll teeth is studied.Finite element software Workbench was used to analyze the elastic deformation of a pair of scroll discs with circular involute as the base bus equation on the wall surface of the scroll teeth in the meshing region,and the time-varying stiffness of the scroll teeth at the meshing position was calculated.Then,the variation of the mesh stiffness of the scroll teeth at different rotational speeds was analyzed.The results show that the time-varying meshing stiffness of scroll compressors changes periodically,increasing first and then decreasing.With the increase of rotational speed,the increase of inertial load makes the walls of dynamic and static scroll teeth closer,but it does not change the position of mesh line between scroll teeth.It is verified that the mesh stiffness of scroll teeth is mainly affected by the elastic deformation of scroll teeth at mesh and the number of mesh points.This conclusion provides a basis for the force analysis of scroll compressor system.