Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

Gear wear is one of the most common gear failures,which changes the mesh relationship of normal gear.A new mesh relationship caused by gear wear affects meshing excitations,such as mesh stiffness and transmission error,and further increases vibration and noise level.This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear.A geometric model for a new mesh relationship with gear wear is proposed,which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error(USTE).Based on the mesh stiffness and USTE considering gear wear,a gear dynamic model is established,and the vibration characteristics of gear wear are numerically studied.Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship.The numerical and experimental results indicate that gear wear does not change the structure of the spectrum,but it alters the amplitude of the meshing frequencies and their sidebands.Several condition indicators,such as root-mean-square,kurtosis,and first-order meshing frequency amplitude,can be regarded as important bases for judging gear wear state.

Quasi-static-model-based wear analysis of helical gears

A quasi-static wear model for helical gears is proposed based on finite element method and Archard's formula to investigate the wear characteristics of tooth surface in real operation conditions. The numerical simulation reveals that the wear depth distributes unevenly along the tooth lead and varies along the tooth profile. The surface wear depth claims its minimal value at the pitch circle and reaches its maximal value near the tooth root of the pinion. The effects of misalignment on wear depth are further investigated to provide useful information for gear designers. The numerical simulation reveals that the vertical misalignment is more influential than the parallel misalignment on the gear wear depth. Therefore, to eliminate the negative effects of misalignment, the misalignment should be strictly controlled.

Numerical Simulation Study on Wear of Spur Gears under Dynamic Conditions

A numerical simulation model is proposed to predict the wear depth of gears,where Archard's wear equation and a nonlinear dynamic model are combined to establish a wear calculation model under dynamic conditions.The dynamic meshing force,determined by the non-linear dynamic model,and the sliding coefficient are used by Archard's wear equation to calculate the surface wear.Then the dynamic meshing force and sliding coefficient would be recalculated according to the surface wear state.After repeated iterations,the simulation results show that the peak and fluctuation of the meshing force increase first,then decrease,and eventually maintain stability during the process of wear.As for the distribution of wear depth,its fluctuation also increases first and then declines.Finally,the distribution of wear depth becomes V-shaped.Comparing the trends of the two factors,it is clear that the meshing force and wear depth are closely related.Moreover,the wear rate maintains a higher constant value first and then declines to a lower constant value.

STUDY ON WEAR AND DESTRUCTION OF HOB IN GEAR HOBBING

The wear and destruction appearances of hobs are researched. The reasons ofthe wear and destruction of hob are analyzed. And the influence of the change of the hobbing forceand the hobbing temperature on the wear and destruction of hob in gear hobbing is also analyzed. Ingear hobbing, the main wear mechanisms are adhesion and ploughing when cutting the 20CrMnTi gearusing W18Cr4V high-speed steel hob.

腐蚀作用下城市轨道车辆齿轮磨损可靠性研究

为解决城市轨道车辆齿轮在腐蚀性环境下的磨损可靠性预测问题,采用非齐次泊松过程和对数高斯分布表征齿面腐蚀坑的萌生和生长,并考虑磨损对腐蚀坑深度的改变,通过分析腐蚀坑对赫兹接触应力、齿面粗糙度的影响,基于Archard磨损理论,以齿面最大累积磨损深度为关键参数建立性能裕量退化模型,构建出一种腐蚀作用下的城市轨道车辆齿轮磨损可靠性分析模型,并对腐蚀过程涉及的参数进行可靠性灵敏度分析。结果表明:随着工作时间的增长,齿轮累积磨损量的不确定性增加,腐蚀对齿轮磨损可靠性的影响程度降低;腐蚀坑生长过程的比例参数、形状参数和最大腐蚀深度对可靠性的灵敏度依次增加,且均与齿轮磨损可靠寿命呈负相关关系。

随机风速下含磨损故障的齿轮系统动力学特性

通过Archard磨损模型计算齿面磨损量,得到了时变啮合刚度,同时考虑齿侧间隙、综合传递误差和随机风速引起的外部激励等因素,建立了含磨损故障的风电机组高速级齿轮传动系统动力学模型,并使用Runge-Kutta法进行求解,分析了不同累计磨损量下风电机组高速级齿轮传动系统的动态特性。研究结果表明:Archard磨损模型符合实际齿轮磨损状态,在节线处磨损最小,在齿顶处的累计磨损量最大;振动位移的波动趋势与输入转矩趋势相反,随着磨损时间的增加,振动位移的波动程度增加;经过5年的磨合期之后,齿轮的主要响应频率的振幅呈线性变化。研究结果为齿轮传动系统的故障诊断与检测提供重要的理论依据。

FZG齿轮试验机方法在齿轮油上的应用研究

齿轮箱设备所用齿轮油最为关键的性能是承载性能。常规理化测试不足以全面评价齿轮油的承载性能,因此国内外研究机构结合机械设备开发了许多评价齿轮油承载性能的试验方法。研究表明:简单的台架测试方法一般与设备实际工况相关性差,在齿轮试验台上使用指定几何结构的齿轮可以更好地表征齿轮润滑剂的承载性能。文章主要阐述了润滑剂对齿轮不同失效模式的影响,以及如何用适当的测试方法量化,并准确表征润滑剂的承载性能。

40Cr钢转动轴齿轮磨损原因

某40Cr钢转动轴在转动测试约35 h后,转动轴齿轮出现磨损现象。采用宏观观察、化学成分分析、扫描电镜分析、金相检验、硬度测试等方法分析了齿轮磨损的原因。结果表明:该转动轴齿轮与齿轮轴套的热处理工艺控制不当,导致齿顶表层晶粒偏大;与该转动轴齿轮匹配的齿轮轴套硬度偏高,使转动轴齿轮发生变形以及齿顶表层材料缺失,缺失的材料形成磨粒磨损,最终导致该转动轴齿轮齿牙缓慢剥落。

Delaunay三角剖分的汽车螺旋锥齿轮磨损检测

由于汽车后桥螺旋锥存在耦合竖向振动,导致齿轮磨损难以精准检测,因此提出Delaunay三角剖分的汽车螺旋锥齿轮磨损检测方法。通过扫描式方法测量齿轮表面的离散数据,对相邻扫描线进行Delaunay三角剖分,完成齿面非特征离散数据分块,实现对齿轮表面区域的全面描述。根据数据分块结果,采用基于Hermite插值的LMD算法,遍历计算三角网格的PF分量幅值,完成齿轮磨损故障的检测。实验结果表明,所提出方法的磨损深度与磨损率检测结果与实测结果基本一致,并且能够对齿轮磨损区域面积进行有效检测,检测精度最高达到98.7%。因此,说明所提出方法能够对齿轮磨损进行有效的检测。

考虑齿面磨损的人字齿轮系统振动特性研究

为揭示齿面磨损对人字齿轮系统动力学的影响,建立了人字齿轮系统12自由度弯扭轴耦合模型,该模型考虑了齿面磨损,啮合误差、啮合刚度等因素。研究了人字齿轮系统不同运行次数下,人字齿轮振动位移和振动速度的变化情况。搭建人字齿轮振动测试试验平台,用于测量在不同扭矩和不同速度下的人字齿轮传动系统的动态特性,探讨了人字齿轮系统各构件在不同运行次数下的振动加速度幅值变化情况。结果表明:当输入转矩相同时,振动加速度幅值随着输入转速的增大而快速增大;当输入转速相同时,振动加速度幅值随着输入转矩的增大没有变化;随着运行次数的增加,齿轮系统各构件的振动位移、振动速度、振动加速度幅值先降低后增大。

Acoustics Based Monitoring and Diagnostics for the Progressive Deterioration of Helical Gearboxes

Gearbox condition monitoring(CM)plays a significant role in ensuring the operational reliability and efficiency of a wide range of critical industrial systems such as wind turbines and helicopters.Accurate and timely diagnosis of gear faults will improve the maintenance of gearboxes operating under sub-optimal conditions,avoid excessive energy consumption and prevent avoidable damages to systems.This study focuses on developing CM for a multi-stage helical gearbox using airborne sound.Based on signal phase alignments,Modulation Signal Bispectrum(MSB)analysis allows random noise and interrupting events in sound signals to be suppressed greatly and obtains nonlinear modulation features in association with gear dynamics.MSB coherence is evaluated for selecting the reliable bi-spectral peaks for indication of gear deterioration.A run-to-failure test of two industrial gearboxes was tested under various loading conditions.Two omnidirectional microphones were fixed near the gearboxes to sense acoustic information during operation.It has been shown that compared against vibration based CM,acoustics can perceive the responses of vibration in a larger areas and contains more comprehensive and stable information related to gear dynamics variation due to wear.Also,the MSB magnitude peaks at the first three harmonic components of gear mesh and rotation components are demonstrated to be sufficient in characterizing the gradual deterioration of gear transmission.Consequently,the combining of MSB peaks with baseline normalization yields more accurate monitoring trends and diagnostics,allowing the gradual deterioration process and gear wear location to be represented more consistently.

复杂工况条件下齿轮传动过程中磨损量预测研究

磨损是齿轮传动过程中的主要失效形式,磨损加剧会使齿轮齿侧间隙非线性增大、传动精度下降及齿面冲击力增大,进而导致齿轮传动系统振动加剧,对齿轮传动性能及设备的稳定运行造成重大影响。为了解决上述问题,提出了复杂工况条件下齿轮传动过程中磨损量预测方法。基于形式磨损指数识别并判定齿轮磨损状态,通过深入分析齿轮磨损机制并以此为基础,绘制典型齿轮磨损过程曲线,计算齿轮传动摩擦力矩数值,构建了齿轮磨损量数学模型;再将已知齿轮状态数值输入至所构建模型中,即可得出齿轮预测磨损量,实现齿轮磨损量的预测。试验结果表明,在3种复杂工况条件下,提出的预测模拟数据更接近于实际参数,验证了磨损量预测的精度。

考虑磨损故障的双渐开线齿轮传动系统动态特性研究

针对目前双渐开线齿轮(DIG)研究过程中齿廓磨损对双渐开线齿轮动态特性的影响问题,对考虑磨损故障的双渐开线齿轮传动系统动态特性进行了研究。首先,进行了双渐开线齿轮接触线长度与齿面载荷计算,考虑相对滑移距离,建立了等效接触模型;然后,进行了双渐开线齿轮齿面累积磨损量、齿轮齿面累积磨损深度的计算,建立了双渐开线齿轮啮合刚度计算模型,进行了磨损故障的双渐开线齿轮刚度的计算;最后,以一对双渐开线齿轮为研究对象,采用集中质量法建立了6自由度动力学模型,研究了齿面磨损对双渐开线齿轮动力学特性的影响。研究结果表明:在运行1×104次载荷循环后,混合弹流润滑状态下,双渐开线齿轮与普通渐开线齿轮(CIG)在节线附近齿根位置的最大累计磨损量差值为0.00207μm,且双渐开线齿轮节线靠近齿顶位置的磨损小于普通渐开线齿轮的磨损;双渐开线齿轮系统在磨损后振动加速度幅值小于普通渐开线斜齿轮的幅值。通过对不同磨损情况下的时域响应进行研究,发现磨损导致双渐开线齿轮传动系统的振动幅值增大。

大模数齿轮齿条副均匀磨损弯曲强度分析及验证

针对齿面磨损条件下大模数齿轮齿条啮合时的齿轮齿根弯曲强度问题,以三峡升船机齿轮齿条传动副为研究对象,搭建立式齿轮齿条起升机构工况模拟实验台,通过齿轮变位方法分析沿齿廓载荷、磨损后齿轮齿厚等相关参数的变化,对正常、1/12磨损、1/6磨损和1/4磨损的齿轮齿根弯曲应力进行解析计算和实验验证。结果表明:齿轮弯曲应力随着磨损加剧和载荷的增大而增大,单齿啮合区间的弯曲应力比双齿啮合区显著增大,单齿啮合占比时间随着磨损量的增加而增加,表明齿轮磨损劣化了传动系统工况,加速了传动系统的性能退化过程。通过对单、双齿段啮合弯曲应力进行定量分析,解析计算与实验验证的误差最大值为4.02%,处于较低水平,2种方法的结果相互验证,保证了分析的正确性和精度。

考虑点蚀情况的双渐开线齿轮动态特性研究

齿轮是机械传动系统的核心部件,点蚀与磨损是其主要失效的形式。为解决齿轮发生点蚀失效时双渐开线齿轮的时变啮合刚度与动态特性不明这一问题,采用接触线百分比法求解了发生点蚀时双渐开线齿轮的啮合刚度,并利用有限元法验证了算法的正确性。首先,对不同点蚀情况进行了分类,分析了不同点蚀数量对双渐开线齿轮接触线长度的影响;然后,基于接触线百分比法,利用轮齿载荷与轮齿变形的比值关系求解了不同点蚀情况下齿轮的啮合刚度,采用有限元法验证了算法的正确性,并对比分析了点蚀对双渐开线与普通渐开线齿轮啮合刚度的影响;最后,建立了两种齿轮的柔性多体动力学模型,基于冲激函数法分析了两种齿轮在不同点蚀情况下的动力学特性。研究结果表明:相同工况条件下,随着点蚀程度的加深,两种类型齿轮啮合刚度均不断减小,动态啮合力及振动角加速度幅值增加,其中双渐开线齿轮啮合力最大值为1.24×10^(5)N,角加速度最大值为2.66×10^(6)°/s^(2);相比于普通渐开线齿轮,双渐开线齿轮在点蚀影响下的啮合刚度变化更稳定,加速度幅值波动更平缓,具有更好的抵抗冲击能力和动力传递稳定性。

风电场齿轮油磨斑直径偏大解决措施

风电场运行中齿轮油磨斑直径偏大,经分析主要是抗磨添加剂缺失导致,因此将含氮硼酸酯抗磨剂应用于齿轮油中,考察其添加方式、用量以及稳定性。结果表明在运行齿轮油中添加1.5%含氮硼酸酯,齿轮油磨斑直径可减小约20%,且对油品的其他性能无不良影响,同时加入含氮硼酸酯的油品经过开口杯老化试验后,齿轮油表现出良好的热稳定性。

考虑中心距安装误差下的齿面磨损特性分析

以重合度为1~2之间的定轴渐开线直齿轮为研究对象,基于Archard磨损模型数值仿真齿面磨损的分布规律,研究齿轮中心距安装误差对齿轮啮合过程的影响,揭示中心距安装误差对齿面磨损的影响机理。结果表明:在0.1%的中心距误差下,中心距的增大会使齿轮的重合度下降,啮合区域变小,啮入点的位置远离齿根,从而减小齿面磨损。

齿面磨损故障对机车传动齿轮啮合刚度的影响

为了保证机车运行的安全性,分析了磨损故障对机车传动齿轮啮合刚度的影响。基于Archard磨损公式和Hertz接触模型,建立了考虑动态磨损系数的机车齿轮齿面磨损数值仿真模型。通过计算发现,主、从动齿轮靠近齿根处磨损深度最大,在节线处磨损深度为0 mm,节线两侧单、双齿交替区域磨损深度出现突变。随后,通过势能法建立了齿轮啮合刚度模型,并在此基础上建立了考虑齿面磨损故障的齿轮啮合刚度模型。通过模型计算发现,磨损故障会减小啮合刚度,在磨损初期,刚度减小不明显,啮合刚度减少量随磨损程度的加剧而增多。

齿轮加工数控刀具的磨损机理与寿命预测研究

数控加工作为现代制造业中重要的加工方式,刀具磨损与寿命管理一直是工程技术领域的重要课题。有效的刀具管理策略可以显著提高加工效率、降低成本、优化加工质量,并对环境保护具有重要意义。因此,对数控加工过程中刀具磨损与寿命管理策略展开深入研究,将为推动数控加工技术的发展和实现可持续制造提供重要支撑。分析了数控加工过程中刀具磨损与寿预测策略。

大型行星齿轮减速器磨损失效问题研究

针对大型行星齿轮减速器的磨损失效问题展开深入研究,旨在提高其可靠性和延长其使用寿命。首先概述行星齿轮减速器的工作原理和结构组成,其次阐述磨损对减速器性能的影响,从材料、设计两大方面分析磨损的原因,并介绍磨损诊断的方法,最后提出材料选择、设计优化、环境改善等改进策略。