Research On Springback Deformation Of Pre-assembly Of Compressor Stator Assembly

The pre-assembly accuracy of the stator assembly determines whether the components can be smoothly installed into the receiver to complete the manufacture of the stator.The pre-assembly of the stator assembly includes two steps which are fixture positioning and spot welding.When the fixture is unloaded,the components will spring back and deform,and it is difficult to ensure the pre-assembly accuracy of the stator components.In order to reduce the pre-assembly springback deformation of the stator assembly,this paper uses a combination of simulation and experiment to improve the fixture structure and control the pre-assembly process parameters.(1)To reduce the springback deformation of the stator assembly,a simulation model for the pre-assembly of the stator assembly is established,the fixture structure is improved,and the pre-assembly process parameters are controlled.According to the pre-assembled fixture structure,the clamping force is calculated and experimentally verified,and the simulation load parameters are determined.Based on the non-manufacturing deviation model and the initial stress method,the spot welding connection is simulated by the method of coupling nodes,and the springback deformation simulation model of the stator assembly pre-assembly is established.The results show that the springback deformation of the stator assembly is small in the middle,and the springback deformation at both ends is large,the maximum is 0.061 mm.The fixture is improved according to the way that the middle of the outer ring baffle is thickened,the inner ring push rod indenter is connected and the middle is hollowed out,and the improved fixture is simulated and analyzed.The simulation results show that the springback deformation is reduced by 84.5%-88.9%.The influence of the clamping force of the fixture,the welding position of the edge strip,and the number of solder joints on the springback deformation is studied,and the pre-assembly process parameters that are conducive to reducing the springback deformation are finally determined.(2)The spot welding simulation model of the stator assembly is established,and the influence of the spot welding thermal stress on the springback deformation is analyzed.By studying the effects of spot welding current,spot welding pressure,and spot welding time on the deformation of the welding joint,the control variable method is used to determine the welding process parameters to make the deformation of the welding joint smaller.Use an ultra-depth-of-field microscope to observe the solder joints and confirm that the quality of solder joints are good which meet the spot welding requirements.Use the determined spot welding process parameters to simulate the spot welding thermal stress of the stator assembly,and compare the numerical value of the spot welding thermal stress with that of the clamping stress.The results show that the spot welding thermal stress is much smaller than the clamping stress,so the spot welding thermal stress can be ignored in the springback deformation simulation based on the initial stress method.(3)The experimental measurement platform is designed,the components are pre-assembled,and the springback deformation measurement experiment is completed.The experimental platform includes a measuring fixture,a pressure control module and a three-coordinate measuring instrument.Design the measuring fixture to avoid the effect of the overall movement of the stator assembly on the springback deformation of the assembly after the pre-assembly fixture is unloaded.The clamping force of the fixture is controlled by the film pressure sensor,the feature point of the component is measured with a three-coordinate measuring instrument,and the measurement data is processed to obtain the springback deformation.The components were assembled with the improved fixture and pre-assembly process parameters,and the springback deformation measurement experiment was completed.The measurement results are consistent with the springback deformation trend of the simulation results,and the error is 23%,indicating that the established springback deformation simulation model can be referenced.The improved fixture structure and pre-assembly process parameters were used for component assembly,and the springback deformation measurement experiment was completed.The experimental results showed that the springback deformation was reduced by 84%-90%,verifying the improved fixture and pre-assembly The process parameters are conducive to the reduction of springback deformation.