| Planetary gear transmission system is widely used in various engineering fields because of its stable structure,large load and large transmission ratio.However,the vibration and noise caused by the installation error and wear in the working process,as well as the influence on its fatigue life,have always been an important problem in the engineering field,especially with the development of modern industry,the planetary gear transmission system is becoming more and more popular In the light-weight design,the inner gear ring is gradually thinned,which will directly affect the service life of planetary gear transmission system.The inner ring gear is the key component of the planetary gear train,and its vibration and stress characteristics under meshing excitation are the main components of its failure.Therefore,it is of great significance for engineering safety to analyze the vibration characteristics and stress characteristics of planetary gear train under meshing excitation of flexible ring gear.In particular,the vibration of lightweight gear ring will be more obvious because of its thin-walled structure,and its profit fluctuation will be more complex.Reasonable analysis of its vibration and stress characteristics under meshing excitation can provide reference value for engineering designers and engineering practice.To sum up,this paper mainly carried out the following research work:Based on the dynamic characteristics of planetary gear system,this paper puts forward a dynamic analysis method.The Newmark-β integral method is used to calculate the load distribution of the planetary gear system It can be seen that the dynamic strain of the tooth root has experienced the process of unilateral compression,bilateral tension and compression and unilateral tension.At the same time,the maximum absolute value of the dynamic strain of the tooth root under different loads is compared,and the maximum error is 8.88%.Finally,the vibration and stress characteristics of the ring gear are calculated by the above method,and the following results are obtained: in the case of non-resonance,the rotation frequency of the planetary gear is the main excitation frequency,while in the case of resonance,the meshing frequency and its modulation frequency dominate and become the main excitation frequency.With the increase of the number of supports,the natural frequency of the ring gear increases,and the speed required to excite the ring gear resonance increases.At the same time,with the increase of the number of supports,the inner ring gear appears the resonance speed zone at the seventh and eighth supports.At the same time,with the increase of the number of supports,the deformation of the inner gear ring gradually evolves from the second-order bending deformation to the first-order bending deformation.In the stress analysis of the ring gear,when the planetary gear is meshed to the supporting position of the inner ring gear,an antisymmetric deformation area will be formed on the symmetrical side of the supporting position due to the meshing force.When the inner ring gear is far away from the support position,the root stress will increase greatly due to the lack of support.For the radial stress analysis,with the extension of the path,the stress first decreases and then increases,the stress gradually evolves from compression bending deformation to tension bending deformation.The results show that the deformation of the ring gear tends to be natural in the case of resonance rather than static.The area of stress fluctuation caused by meshing deformation of thin-walled ring gear increases,and the maximum stress of tooth root occurs on the side of the ring gear with manual deformation,and the tensile stress is twice of the compressive stress.In the meshing position,due to the influence of the flexibility of the thin-walled ring gear,the stress of the outer gear body of the ring gear is more concentrated than that of the tooth root. |
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