Gear assembly errors can lead to the increase of vibration and noise of the system,which affect the stability of system.The influence can be compensated by tooth modification.Firstly,an improved three-dimensional load...Gear assembly errors can lead to the increase of vibration and noise of the system,which affect the stability of system.The influence can be compensated by tooth modification.Firstly,an improved three-dimensional loaded tooth contact analysis(3D-LTCA)method which can consider tooth modification and coupling assembly errors is proposed,and mesh stiffness calculated by proposed method is verified by MASTA software.Secondly,based on neural network,the surrogate model(SM)that maps the relationship between modification parameters and mesh mechanical parameters is established,and its accuracy is verified.Finally,SM is introduced to establish an optimization model with the target of minimizing mesh stiffness variations and obtaining more even load distribution on mesh surface.The results show that even considering training time,the efficiency of gear pair optimization by surrogate model is still much higher than that by LTCA method.After optimization,the mesh stiffness fluctuation of gear pair with coupling assembly error is reduced by 34.10%,and difference in average contact stresses between left and right regions of the mesh surface is reduced by 62.84%.展开更多
A novel specific type of worm drive, so-called end face engagement worm gear（EFEWD）, is originally presented to minimize or overcome the gear backlash. Different factors, including the three different types, contact...A novel specific type of worm drive, so-called end face engagement worm gear（EFEWD）, is originally presented to minimize or overcome the gear backlash. Different factors, including the three different types, contact curves, tooth profile, lubrication angle and the induced normal curvature are taken into account to investigate the meshing characteristics and create the profile of a novel specific type of worm drive through mathematical models and theoretical analysis. The tooth of the worm wheel is very specific with the sine-shaped tooth which is located at the alveolus of the worm and the tooth profile of a worm is generated by the meshing movement of the worm wheel with the sine-shaped tooth, but just the end face of the worm（with three different typical meshing types） is adapted to meshing, and therefore an extraordinary manufacturing methods is used to generate the profile of the end face engagement worm. The research results indicates that the bearing contacts of the generated conjugate hourglass worm gear set are in line contacts, with certain advantages of no-backlash, high precision and high operating efficiency over other gears and gear systems besides the end face engagement worm gear drive may improve bearing contact, reduce the level of transmission errors and lessen the sensitivity to errors of alignment. Also, the end face engagement worm can be easily made with superior meshing and lubrication performance compared with the conventional techniques. In particular, the meshing and lubrication performance of the end face engagement worm gear by using the end face to meshing can be increased over 10% and 7%, respectively. This investigate is expect to provide a new insight on the design of the future no-backlash worm drive for industry.展开更多
End worm gear drives are characterized by their multi-tooth contact,compact contour,and theoretical potential to overcome some inherent flaws of cylindrical worm drives.However,quantitative basic research on end worm ...End worm gear drives are characterized by their multi-tooth contact,compact contour,and theoretical potential to overcome some inherent flaws of cylindrical worm drives.However,quantitative basic research on end worm gear drives is currently inadequate,which hinders the development of this transmission.This work focuses on the computational design of end worm gear drives and proposes a new Niemann-type design.Meshing models of the proposed drive are established,and its engagement theory is deduced systematically.Based on the derived tooth surface equations,an innovative research methodology for the tooth curve geometry of the end worm gear is created,and the tooth curve in the worm gear reference plane is proved to be a spiral.An improved formula for the lubrication angle is developed,which can provide more rational numerical results for the angle.Theoretically,the modified formula is universally applicable for line contact drives and can be used to quantitatively investigate the lubrication level between the teeth for the proposed drive.Simulation outcomes demonstrate the favorable characteristics of the transmission,including broad conjugate areas,even contact lines,and fine global lubrication state.展开更多
基金Project(11972112)supported by the National Natural Science Foundation of ChinaProject(N2103024)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(J2019-IV-0018-0086)supported by the National Science and Technology Major Project,China。
文摘Gear assembly errors can lead to the increase of vibration and noise of the system,which affect the stability of system.The influence can be compensated by tooth modification.Firstly,an improved three-dimensional loaded tooth contact analysis(3D-LTCA)method which can consider tooth modification and coupling assembly errors is proposed,and mesh stiffness calculated by proposed method is verified by MASTA software.Secondly,based on neural network,the surrogate model(SM)that maps the relationship between modification parameters and mesh mechanical parameters is established,and its accuracy is verified.Finally,SM is introduced to establish an optimization model with the target of minimizing mesh stiffness variations and obtaining more even load distribution on mesh surface.The results show that even considering training time,the efficiency of gear pair optimization by surrogate model is still much higher than that by LTCA method.After optimization,the mesh stiffness fluctuation of gear pair with coupling assembly error is reduced by 34.10%,and difference in average contact stresses between left and right regions of the mesh surface is reduced by 62.84%.
基金Supported by National Natural Science Foundation of China(Grant No.51305356)Spring Sunshine Plan of Ministry of Education of China(Grant No.14202505)Talent Introduction of Xihua University,China(Grant No.Z1220217)
文摘A novel specific type of worm drive, so-called end face engagement worm gear（EFEWD）, is originally presented to minimize or overcome the gear backlash. Different factors, including the three different types, contact curves, tooth profile, lubrication angle and the induced normal curvature are taken into account to investigate the meshing characteristics and create the profile of a novel specific type of worm drive through mathematical models and theoretical analysis. The tooth of the worm wheel is very specific with the sine-shaped tooth which is located at the alveolus of the worm and the tooth profile of a worm is generated by the meshing movement of the worm wheel with the sine-shaped tooth, but just the end face of the worm（with three different typical meshing types） is adapted to meshing, and therefore an extraordinary manufacturing methods is used to generate the profile of the end face engagement worm. The research results indicates that the bearing contacts of the generated conjugate hourglass worm gear set are in line contacts, with certain advantages of no-backlash, high precision and high operating efficiency over other gears and gear systems besides the end face engagement worm gear drive may improve bearing contact, reduce the level of transmission errors and lessen the sensitivity to errors of alignment. Also, the end face engagement worm can be easily made with superior meshing and lubrication performance compared with the conventional techniques. In particular, the meshing and lubrication performance of the end face engagement worm gear by using the end face to meshing can be increased over 10% and 7%, respectively. This investigate is expect to provide a new insight on the design of the future no-backlash worm drive for industry.
基金supported by the National Natural Science Foundation of China(Grant Nos.52075083 and 52205069)the Open Fund of the Key Laboratory for Metallurgical Equipment and Control of Education Ministry in Wuhan University of Science and Technology,China(Grant Nos.MECOF2022B04 and MECOF2023B01)the 2023 AGMA Foundation Scholarship Program,USA.
文摘End worm gear drives are characterized by their multi-tooth contact,compact contour,and theoretical potential to overcome some inherent flaws of cylindrical worm drives.However,quantitative basic research on end worm gear drives is currently inadequate,which hinders the development of this transmission.This work focuses on the computational design of end worm gear drives and proposes a new Niemann-type design.Meshing models of the proposed drive are established,and its engagement theory is deduced systematically.Based on the derived tooth surface equations,an innovative research methodology for the tooth curve geometry of the end worm gear is created,and the tooth curve in the worm gear reference plane is proved to be a spiral.An improved formula for the lubrication angle is developed,which can provide more rational numerical results for the angle.Theoretically,the modified formula is universally applicable for line contact drives and can be used to quantitatively investigate the lubrication level between the teeth for the proposed drive.Simulation outcomes demonstrate the favorable characteristics of the transmission,including broad conjugate areas,even contact lines,and fine global lubrication state.
