Analysis of the Meshing of Crown Gear Coupling

This paper presents an analysis result of three-dimensional meshing of crown gear coupling （CGC） surfaces of crown gear and internal gear are established. The equation of internal gear surface is given. The equation of conjugate surface of crown gear is solved according to the principle of gearing, and that of non-conjugate crown gear is derived with crown curve of a circular arc. The meshing state of conjugate and non-conjugate surfaces is analyzed through computation of contact lines and points. It is concluded that the meshing of conjugate CGC is line-contact, there are several pairs of teeth engage simultaneously, and non-conjugate CGC has point-contact condition of meshing and only 2 pairs of teeth engage in theory.

Dynamic Simulation for Rigid-Flexible Coupling Model of Gear Transmission System Based on ADAMS

The influence of the flexible body for the motion of gear transmission system is analyzed and the foundation for a more accurate assessment of gear transmission system is established when it has battle damage faults. By using Pro / E software,the virtual prototype model of gear transmission system in the speed reducer is established,and the rigid model and rigid-flexible coupling model are simulated respectively in ADAMS to obtain the data of gear meshing force. It can be concluded that rigid-flexible coupling model can reflect the real motion better than rigid model by comparing the simulation data of two models.

Dynamic response of large increased pressure wind tunnel rotor-gear coupling system with parallel misalignment

To study the misalignment of gear coupling, this paper analyzed the distortion of the tooth of gear coupling on the base of gear coupling’s motion under parallel misalignment, and derived the specific expression of additive radial force, which produced by the rotor’ torque. The motion differential equations of the large increased pressure wind tunnel rotor-gear coupling system were derived by the finite element method. Newmark integral method was applied to calculate the dynamic response of the system with parallel misalignment. The numerical results show that: under the effect of additive radial force, the static misalignment can arouse 2X frequency component lateral vibration; the dynamic misalignment can arouse2X,4X,6X multiple frequency components lateral vibration. The 2X frequency component is obvious. The additive radial force of the gear coupling can arouse lateral vibration with even multiple frequency components.

Bifurcation and chaos study on transverse-torsional coupled 2K-H planetary gear train with multiple clearances

A new non-linear transverse-torsional coupled model was proposed for 2K-H planetary gear train, and gear's geometric eccentricity error, comprehensive transmission error, time-varying meshing stiffness, sun-planet and planet-ring gear pair's backlashes and sun gear's bearing clearance were taken into consideration. The solution of differential governing equation of motion was solved by applying variable step-size Runge-Kutta numerical integration method. The system motion state was investigated systematically and qualitatively, and exhibited diverse characteristics of bifurcation and chaos as well as non-linear behavior under different bifurcation parameters including meshing frequency, sun-planet backlash, planet-ring backlash and sun gear's bearing clearance. Analysis results show that the increasing damping could suppress the region of chaotic motion and improve the system's stability significantly. The route of crisis to chaotic motion was observed under the bifurcation parameter of meshing frequency. However, the routes of period doubling and crisis to chaos were identified under the bifurcation parameter of sun-planet backlash; besides, several different types of routes to chaos were observed and coexisted under the bifurcation parameter of planet-ring backlash including period doubling, Hopf bifurcation, 3T-periodic channel and crisis. Additionally, planet-ring backlash generated a strong coupling effect to system's non-linear behavior while the sun gear's bearing clearance produced weak coupling effect. Finally, quasi-periodic motion could be found under all above–mentioned bifurcation parameters and closely associated with the 3T-periodic motion.

Coupled lateral-torsional-axial vibrations of a helical gear-rotor-bearing system

Considering the axial and radial loads, a math- ematical model of angular contact ball bearing is deduced with Hertz contact theory. With the coupling effects of lateral, torsional and axial vibrations taken into account, a lumped-parameter nonlinear dynamic model of helical gearrotor-bearing system （HGRBS） is established to obtain the transmission system dynamic response to the changes of dif- ferent parameters. The vibration differential equations of the drive system are derived through the Lagrange equation, which considers the kinetic and potential energies, the dis- sipative function and the internal/external excitation. Based on the Runge-Kutta numerical method, the dynamics of the HGRBS is investigated, which describes vibration properties of HGRBS more comprehensively. The results show that the vibration amplitudes have obvious fluctuation, and the frequency multiplication and random frequency components become increasingly obvious with changing rotational speed and eccentricity at gear and bearing positions. Axial vibration of the HGRBS also has some fluctuations. The bearing has self-variable stiffness frequency, which should be avoided in engineering design. In addition, the bearing clearance needs little attention due to its slightly discernible effect on vibration response. It is suggested that a careful examination should be made in modelling the nonlinear dynamic behavior of a helical gear-rotor-bearing system.

Nonlinear Dynamic Analysis of Coupled Gear-Rotor-Bearing System with the Effect of Internal and External Excitations

Extensive studies on nonlinear dynamics of gear systems with internal excitation or external excitation respectively have been carried out. However, the nonlinear characteristics of gear systems under combined internal and external excitations are scarcely investigated. An eight-degree-of-freedom（8-DOF） nonlinear spur gear-rotor-bearing model, which contains backlash, transmission error, eccentricity, gravity and input/output torque, is established, and the coupled lateral-torsional vibration characteristics are studied. Based on the equations of motion, the coupled spur gear-rotor-bearing system（SGRBS） is investigated using the Runge-Kutta numerical method, and the effects of rotational speed, error fluctuation and load fluctuation on the dynamic responses are explored. The results show that a diverse range of nonlinear dynamic characteristics such as periodic motion, quasi-periodic motion, chaotic behaviors and impacts exhibited in the system are strongly attributed to the interaction between internal and external excitations. Significantly, the changing rotational speed could effectively control the vibration of the system. Vibration level increases with the increasing error fluctuation. Whereas the load fluctuation has an influence on the nonlinear dynamic characteristics and the increasing excitation force amplitude makes the vibration amplitude increase, the chaotic motion may be restricted. The proposed model and numerical results can be used for diagnosis of faults and vibration control of practical SGRBS.

Bending-Torsional Coupled Vibration Test of Large Power Gear Transmission System

In order to test the bending-torsional coupled vibration characteristics of the multi-shafts gear transmission system of large power vehicles,a torsional vibration exciter was used to apply torsional excitation on the gear transmission systems and thirty-two acceleration sensors were used to measure the tangential acceleration of each shaft.Torsional vibration signals and bending vibration signals of each measuring point were obtained by calculation of the four-point-response signal.The modal parameters of gear transmission systems including nature frequency,modal shape and modal damping ratio were obtained by identifying modal parameters of the torsional vibration signal and bending vibration signal.The characteristic of the bending vibration and torsional vibration of the gear systems were studied through the analysis of the nature frequency and modal shape.The nonlinearity characteristic of the gear transmission system was investigated through single frequency excitation test,which can be the foundation for further nonlinearity research.

Modeling and Simulation of Power Coupling System in Hydraulic Hybrid City Bus

In order to solve the coupling problem of power in Hydraulic Hybrid City Bus (HHB), a hydraulic hybrid power coupling system based on planetary gear transmission principle is proposed in this paper. The system consists of diesel engine, power coupler, hydraulic pump/motor, etc. The realizable operating modes of power coupling system are analyzed in this paper. Under coordination of clutches, the engine driven mode, hydraulic driven mode, hybrid driven mode, hydraulic engine-start mode and braking energy recovery mode are realizable. Based on Lagrange equation, kinetic analysis and kinematics analyses are presented. In addition, the simulation model of the power coupling system is proposed, which includes diesel engine model, power coupler model, hydraulic pump/motor model, etc. The example simulation analysis is proposed under the hybrid driven mode;the results show that the power coupling system proposed in this paper can realize power coupling of hydraulic hybrid city bus. Compared with traditional city bus, the hydraulic hybrid city bus can choose small-displacement engine so as to improve fuel economy and dynamic property.

Coupling for Parallel Non-Collinear Shafts

A novel coupling for two parallel shafts with non-collinear axes has been developed and used in a cycloidal transmission with magnetic gears. Such a coupling has been designed as an alternative to traditional couplings to transmit the rotation from the orbiting gear to the output shaft. The driving shaft transmits a couple consisting of two equal and opposite forces to a central element which, in turn, transmits the same couple, also consisting of two equal and opposite forces to the driven shaft. This novel coupling was successfully used instead of a traditional coupling resulting in, not only a smother operation, but also a more efficient power transmission.

FINITE ELEMENT SOLUTION TO COUPLED THERMO－ELASTICCONTACT STRESS AND IMPACTRESPONSE OF MESHING GEARS

A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution of meshing gears is developed. The versatility of the procedure for both numerical accuracy and computational efficiency is verified by numerical analysis of meshing gear teeth.

GEAREX系列齿式锥套联轴器拆卸和安装方法

分析了GEAREX系列齿式锥套联轴器的结构。重点介绍了热装法的步骤、注意事项及轴的对中方法。结合维修实际,总结出安全的拆卸步骤,并设计了专用拆卸拉拔器。对石油钻井现场的锥套联轴器维修有指导意义。

GEAR CRACK EARLY DIAGNOSIS USING BISPECTRUM DIAGONAL SLICE

A study of bispectral analysis in gearbox condition monitoring is presented.The theory of bispectrum and quadratic phase coupling (QPC) is first introduced, and then equationsfor computing bispectrum slices are obtained. To meet the needs of online monitoring, a simplifiedmethod of computing bispectrum diagonal slice is adopted. Industrial gearbox vibration signalsmeasured from normal and tooth cracked conditions are analyzed using the above method. Experimentsresults indicate that bispectrum can effectively suppress the additive Gaussian noise andchracterize the QPC phenomenon. It is also shown that the 1-D bispectrum diagonal slice can capturethe non-Gaussian and nonlinear feature of gearbox vibration when crack occurred, hence, this methodcan be employed to gearbox real time monitoring and early diagnosis.

Influence of support stiffness on vibrations of a planet gear system considering ring with flexible support

Planet gear systems(PGSs)are key components of transmission mechanisms.Structural and material characteristics of gearbox and shaft can affect the support stiffness and vibrations of PGSs.The ring gear flexibility should affect the vibrations of PGSs too.However,most previous work did not completely consider the effects of the ring gear flexibility on the vibrations of PGSs and flexible supports of ring and sun gears.Thus,this paper presents a flexible-rigid coupling multi-body dynamic(FMBD)model for a PGS with the flexible supports and ring gear flexibility.A finite element model of ring gear is established to formulate the ring gear flexibility.The influences of clearance and damping of planet bearings on the vibrations of PGS are considered.The effects of flexible supports and ring gear flexibility on the vibrations of PGS under different moment and speed conditions are studied.The statistical parameters and peak frequencies of PGS from the proposed FMBD and previous rigid multi-body dynamic(RMBD)models are compared.The results denote that the flexible support has a great effect on the vibrations of PGS.This paper can provide some guidance for the support structure design and vibration control for PGSs.

Dynamic characteristics of gear system under different micro-topographies with the same roughness on tooth surface

The topography of gear meshing interfaces is one of the key factors affecting the dynamic characteristics of the gear transmission system.In order to obtain the contact characteristics of meshing gear pair with different surface micro-topographies,an interface feature model and a tribo-dynamics coupling model for the gear system are proposed in this paper.The effects of the gear tooth surface micro-topography on the oil film distribution,contact damping and friction are considered.The time-varying meshing stiffness and the static transmission error are included in the abovementioned models.An exemplary gear pair is analyzed using the proposed models to investigate the influence of the surface micro-topography on the dynamic characteristics of gear system under different micro-topographies and input torque conditions.Simulation results show that the effects of gear tooth micro-topography on the gear dynamic responses(including the friction and the vicious damping at the gear meshing interface and the vibration in the direction of offline of action)are highly dependent on the regularity of tooth surface.The vibration and noise can be significantly controlled by manufacturing a regular gear tooth profiles instead of random profiles.

Modelling and Vibration of Gear Drive Systems Influenced by Real Face Width

Gear drives are one of the most common parts in many rotating machinery. If the gear drive runs under lower torque load, nonlinear effects like gear mesh interruption can occur and vibration is accompanied by impact motions of the gears, This paper presents an original method of the mathematical modelling of gear drive nonlinear vibrations by using the modal synthesis method with degrees of freedom number reduction. The model respects nonlinearities caused by gear mesh interruption, parametric gearing excitation caused by time-varying meshing stiffness and nonlinear contact forces acting between journals of the rolling-element bearings and the outer housing. The nonlinear model is then used for investigation of gear drive vibration, especially for constant gear mesh determination. The theoretical method is applied for investigating of test gear drive nonlinear vibration.

全齿轮耦合机器人齿侧间隙建模与公差仿真

鉴于全齿轮耦合机器人齿轮传动链长、反转频率高的特点,分析机器人的结构和传动原理.为了减小侧隙对机器人传动精度的影响,提出齿侧间隙理论建模及三维公差仿真分析方法.针对驱动端的圆柱齿轮机构,对齿侧间隙进行理论建模和公差仿真分析,两者相吻合.针对关节处的圆锥齿轮机构,提出将圆锥齿轮副等效为假想圆柱齿轮副的侧隙建模方法,与公差仿真分析结果吻合.以机器人肩关节偏摆传动链为分析对象计算机器人末端误差,为了降低齿侧间隙及其导致的传动链回程误差,提出圆锥齿轮加垫的计算方法和电机转角补偿方法,通过实验验证该补偿方法的有效性.

矿用卡车AMT齿轮传动系统可靠性分析

为较准确预测矿用卡车(automated manual transmission,AMT)变速器齿轮传动系统的动态可靠性,考虑关键构件的柔性及内外部载荷激励的影响,构建了AMT齿轮传动系统刚柔耦合动力学模型,针对服役频次高或载荷恶劣的变速器六挡和七挡传动系统进行了动载荷分析。在此基础上,考虑传动系统载荷动态变化、零件强度退化和各零件之间失效的相关性,对该AMT变速器六挡和七挡传动系统的动态可靠性进行研究,找到了该AMT变速器传动系统的薄弱零部件环节,获得了传动系统及其零部件的可靠度随服役时间的变化规律,为矿用卡车AMT变速器齿轮传动系统的可靠性设计及性能提升奠定了基础。

一种零泄漏的齿轮泵设计

介绍了齿轮泵的设计过程,从变位系数和压力角两个方面着手,重点阐述了依据排量和中心距设计齿轮参数的选择方法。为实现零泄露,采用了磁性联轴器代替机械密封,结构更紧凑,密封性更好。齿轮泵整体结构小巧,能满足实际需求。

基于RCMDE和ISOMAP的行星齿轮传动耦合故障辨识研究

现有针对行星齿轮箱的故障诊断方法一般仅研究单一故障,但实际行星齿轮箱的故障一般由多个故障耦合而成,耦合故障的故障机理比单一故障的故障机理更复杂,振动信号中的非线性因素对特征提取的干扰更严重。针对该问题,提出了一种基于精细复合多尺度散度熵(RCMDE)、等距特征映射(ISOMAP)和遗传算法优化核极限学习机(GA-KELM)的行星齿轮箱耦合故障诊断方法。首先,利用振动加速度计采集了行星齿轮箱单一故障和耦合故障下运行时的振动信号,构建了故障数据集;随后,利用RCMDE提取了行星齿轮箱振动信号的故障特征,建立了初始的特征样本;接着,利用ISOMAP对故障特征进行了降维,并以可视化的方式获取了低维的特征样本;最后,将新特征输入至GA-KELM分类器中,对行星齿轮箱的不同故障类型进行了识别,并基于行星齿轮箱多点损伤样本,对RCMDE方法的可靠性进行了研究。研究结果表明:基于RCMDE和ISOMAP的故障特征提取方法能够有效提取振动信号中的故障特征,而GA-KELM的故障诊断准确率达到了98.13%,平均诊断准确率达到了96.25%。相较其他故障特征提取方法,基于RCMDE、ISOMAP和GA-KELM的行星齿轮箱耦合故障诊断方法能够更好地诊断行星齿轮箱的耦合故障,具有更高的诊断准确率。

高温超导磁力传动的发展现状及前景

鉴于高温超导材料具有高载流、强捕获磁场特性与迈斯纳效应,将高温超导材料应用于磁力传动装置,可在实现无接触转矩传输的同时,显著提高转矩密度、传动效率等性能。国内外已开展高温超导磁力传动的理论与应用研究工作,并取得了相应的进展。以高温超导磁力耦合器和高温超导磁齿轮为研究对象,通过调研国内外相关文献,从结构及原理、建模与分析两方面综述高温超导材料在磁力传动领域的研究现状。在此研究基础上,进一步探讨高温超导磁力传动研究在创新拓扑结构设计、冷却与供电、超导磁体交流损耗、复杂传输特性的多目标优化所面临的问题及未来发展前景。