Research On Design And Modification Method Of Cylindrical Gears With Different Precision Grades

As a basic part of the mechanical system to transmit motion and force,helical gears have the advantages of high bearing capacity,stable transmission,high transmission efficiency,long service life and so on.The level of the gear precision directly determines the quality of the meshing transmission,and then affects the quality of the mechanical system.The evaluation of the gear precision grade is based on the result of the comprehensive error.However,the diversity and complexity of the errors have brought great difficulties to the research of the meshing performance of helical gears.For this reason,this paper presents the design and modification of helical gears with different precision.Specific research contents are as follows:According to the existing standards for gear accuracy(GBT10095.1-2008)definition of helix error and tooth profile error,we can establish the mathematical model with helical line error and tooth profile error,and then propose a construction method of helical gear 3D model with different precision.The finite element model of helical cylindrical gear transmission is established,and the influence of different precision grades and different errors on the performance of gear meshing transmission is revealed through the finite element simulation.The results show that the equivalent stress,the bending stress,the transmission error and the contact pressure value of the gear meshing transmission process are increased in different degrees owing to the reduction of precision grade,and the gear meshing transmission performance is deteriorated;which makes the greatest impact on equivalent force,bending stress,transmission error and contact pressure value is parabolic convex(helix error)-parabolic convex(tooth profile error);which makes the minimal impact is straight line type(helix error)-parabolic concave(tooth profile error).At last,according to the analysis results of the meshing performance of helical gears with different precision levels,the model of the straight line type(helix error)-parabolic concave(tooth profile error)is selected.The modification results showed that the bending stress and the contact pressure decreases in meshing process,the transmission error amplitude decreases.Gear modification is a good way to avoid the gear's mesh in-out impacts,reducing vibration and noise.The research provides important theoretical value and practical significance on founding on design and modification theory of helical cylindrical gears with different precision levels,improvement of the meshing performance of helical cylindrical gears,promotion of application and development of high performance helical gear transmission technology.