Study On The Influence Of Axis Parallelism Error On The Tooth Bending Stress Of Spur Gears

As a typical transmission mechanism,the gear reducer is widely used in various mechanical equipment such as lathes and automobiles.The parallelism error of the gear pair generally exists in the gear set of the reducer.The parallelism error of the gear pair will cause the gear axis to shift,which will cause the box vibration to produce noise.In severe cases,the gear teeth will be broken and the reducer will be scrapped in advance.At present,the reliability requirements of the gear transmission system of the reducer are getting higher and higher.Therefore,it is necessary to further investigate the influence of the parallelism error of the gear pair on the bending stress of the tooth root,and provide ideas for the optimal design of the gear set.Therefore,it is necessary to study the effect of parallelism error on tooth root bending stress through a combination of simulation and experiment on the basis of a single research method.In this research,the first-stage reducer of involute cylindrical gear set is taken as the research object,and the effect of parallelism error on tooth root bending stress is studied through the combination of simulation and experiment.The main work contents are as follows:(1)Based on the basic principle of the parallelism error of the reducer gear pair,comprehensively considering the design specifications of the first-stage reducer box,two different parallelism error adjustment schemes of eccentric type and gasket type are designed,and the two are analyzed by comparison the advantages and disadvantages of the scheme,the adjustment range and the difficulty of implementation,the gasket type adjustment was selected as the scheme for the stress test experiment of the gearbox,which provided a theoretical basis for the subsequent simulation and experiment.(2)Based on the principle of image vision measurement,a non-contact gear pair parallelism error measurement method was developed.The CCD camera was used to capture the image of the gear set from the horizontal and vertical directions,and theimage preprocessing,contour extraction,and axis fitting were used to solve the axis equation of the gear shaft,which provided an experimental basis for studying the dynamic characteristics of the gear in service.(3)Establish a finite element model of gear pair transmission with different parallelism errors,perform dynamic finite element simulation analysis on the transmission models with different parallelism errors,and extract the tooth root bending stress curve of three consecutive pairs of meshing teeth of the master and driven wheels.The instantaneous curve of speed and torque,the effect of axis parallelism error on the force and service operation of gear teeth is studied.(4)A gear transimission test bench with adjustable parallelism error was built,and a strain acquisition system composed of strain gauge acquisition cards was used to test the tooth root strain value under different axis parallelism errors and convert it into a corresponding stress curve figure,through comparison with the meshing stress curve obtained by simulation,verify the effect of axis parallelism error on the bending deformation of the dangerous root section.At the same time,the real-time speed and torque of the main and driven wheels under different working conditions are extracted to verify the influence of the axis parallelism error on the operating state of the gear set.