The failure types in gear systems vary,with typical ones mainly including pitting,cracking,wear,and broken teeth.Different modeling and stiffness calculation methods have been developed for various gear failure types....The failure types in gear systems vary,with typical ones mainly including pitting,cracking,wear,and broken teeth.Different modeling and stiffness calculation methods have been developed for various gear failure types.A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness(TVMS)of faulty gears resulting from the use of different methods.Specifically,a gear tooth is discretized into a large number of microelements expressed with a matrix,and unified models of typical gear failures are built by adjusting the values of the matrix microelements.The values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method(PEM),so the matrix-based failure model can be perfectly matched with PEM.Afterward,a unified method for TVMS is established.Modeling of healthy and faulty gears with pitting,wear,crack,and broken tooth is performed with the matrix equation,and the corresponding TVMS values are calculated by incorporating the matrix models with PEM.On the basis of the results,the mechanism of typical fault types that affect TVMS is analyzed,and the conclusions are verified through the finite element method.The developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.展开更多
Profile shift is a highly effective technique for optimizing the performance of spur gear transmission systems.However,tooth surface wear is inevitable during gear meshing due to inadequate lubrication and long-term o...Profile shift is a highly effective technique for optimizing the performance of spur gear transmission systems.However,tooth surface wear is inevitable during gear meshing due to inadequate lubrication and long-term operation.Both profile shift and tooth surface wear(TSW)can impact the meshing characteristics by altering the involute tooth profile.In this study,a tooth stiffness model of spur gears that incorporates profile shift,TSW,tooth deformation,tooth contact deformation,fillet-foundation deformation,and gear body structure coupling is established.This model efficiently and accurately determines the time-varying mesh stiffness(TVMS).Additionally,an improved wear depth prediction method for spur gears is developed,which takes into consideration the mutually prime teeth numbers and more accurately reflects actual gear meshing conditions.Results show that consideration of the mutual prime of teeth numbers will have a certain impact on the TSW process.Furthermore,the finite element method(FEM)is employed to accurately verify the values of TVMS and load sharing ratio(LSR)of profile-shifted gears and worn gears.This study quantitatively analyzes the effect of profile shift on the surface wear process,which suggests that gear profile shift can partially alleviate the negative effects of TSW.The contribution of this study provides valuable insights into the design and maintenance of spur gear systems.展开更多
An improved variable cross‐section cantilever beam model for evaluating the time‐varying mesh stiffness(TVMS)of the perfect gear tooth is developed in which the tooth number of driving gear is less than 42 and that ...An improved variable cross‐section cantilever beam model for evaluating the time‐varying mesh stiffness(TVMS)of the perfect gear tooth is developed in which the tooth number of driving gear is less than 42 and that of driven is more than 42.The TVMS obtained by the proposed method is compared with the result without considering the misalignment between the base circle and gear root.Four types of root crack models and changes inTVMS of 13‐crack levels are presented.The fault vibration characteristic of a single‐stage spur gear reducer with root crack is ana-lyzed and the correctness is qualitatively verified by the vibration signals of an experimental gearbox with crack or missing failure.The results presented in this paper are of great significance for a deep understanding of the possible causes of vibration and noise of gears and provide a theoretical foundation for the fault diagnosis of the gearbox.展开更多
基金supported in part by the National Natural Science Foundation of China(Grant Nos.52175122 and 52075456)the Sichuan Science and Technology Program,China(Grant No.2023NSFSC0362)+1 种基金the Sichuan Province Innovative Talent Funding Project for Postdoctoral Fellows,China(Grant No.BX202214)the China Postdoctoral Science Foundation(Grant No.2023M732917).
文摘The failure types in gear systems vary,with typical ones mainly including pitting,cracking,wear,and broken teeth.Different modeling and stiffness calculation methods have been developed for various gear failure types.A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness(TVMS)of faulty gears resulting from the use of different methods.Specifically,a gear tooth is discretized into a large number of microelements expressed with a matrix,and unified models of typical gear failures are built by adjusting the values of the matrix microelements.The values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method(PEM),so the matrix-based failure model can be perfectly matched with PEM.Afterward,a unified method for TVMS is established.Modeling of healthy and faulty gears with pitting,wear,crack,and broken tooth is performed with the matrix equation,and the corresponding TVMS values are calculated by incorporating the matrix models with PEM.On the basis of the results,the mechanism of typical fault types that affect TVMS is analyzed,and the conclusions are verified through the finite element method.The developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.
基金Supported by National Natural Science Foundation of China (Grant No.52275061)。
文摘Profile shift is a highly effective technique for optimizing the performance of spur gear transmission systems.However,tooth surface wear is inevitable during gear meshing due to inadequate lubrication and long-term operation.Both profile shift and tooth surface wear(TSW)can impact the meshing characteristics by altering the involute tooth profile.In this study,a tooth stiffness model of spur gears that incorporates profile shift,TSW,tooth deformation,tooth contact deformation,fillet-foundation deformation,and gear body structure coupling is established.This model efficiently and accurately determines the time-varying mesh stiffness(TVMS).Additionally,an improved wear depth prediction method for spur gears is developed,which takes into consideration the mutually prime teeth numbers and more accurately reflects actual gear meshing conditions.Results show that consideration of the mutual prime of teeth numbers will have a certain impact on the TSW process.Furthermore,the finite element method(FEM)is employed to accurately verify the values of TVMS and load sharing ratio(LSR)of profile-shifted gears and worn gears.This study quantitatively analyzes the effect of profile shift on the surface wear process,which suggests that gear profile shift can partially alleviate the negative effects of TSW.The contribution of this study provides valuable insights into the design and maintenance of spur gear systems.
文摘齿轮副的时变啮合刚度(Time-varying meshing stiffness,TVMS)是机械动力学分析中一个极为重要的参数,其准确程度直接影响着动力学分析结果的准确性。首先,从理论角度推导了剪切刚度的计算公式,并在案例分析中应用,将求得结果与有限元分析结果进行对比,结果显示相差较小;然后,建立了一种新的裂纹故障模型——轮齿双侧非对称裂纹模型;在基于精确全齿廓的能量法基础上,推导了轮齿双侧裂纹模型的时变啮合刚度计算公式,分析了裂纹形状参数对时变刚度的影响;最后,通过有限元法(Finite element method,FEM)进行了分析验证。结果表明,有限元法和能量法计算的结果基本一致。
基金National Natural Science Foundation of China,Grant/Award Numbers:11790282,12032017,11802184,11902205,12002221S&T Program of Hebei,Grant/Award Number:20310803DNatural Science Foundation of Hebei Province,Grant/Award Number:A2020210028。
文摘An improved variable cross‐section cantilever beam model for evaluating the time‐varying mesh stiffness(TVMS)of the perfect gear tooth is developed in which the tooth number of driving gear is less than 42 and that of driven is more than 42.The TVMS obtained by the proposed method is compared with the result without considering the misalignment between the base circle and gear root.Four types of root crack models and changes inTVMS of 13‐crack levels are presented.The fault vibration characteristic of a single‐stage spur gear reducer with root crack is ana-lyzed and the correctness is qualitatively verified by the vibration signals of an experimental gearbox with crack or missing failure.The results presented in this paper are of great significance for a deep understanding of the possible causes of vibration and noise of gears and provide a theoretical foundation for the fault diagnosis of the gearbox.
