重载齿轮的最佳轮齿修形

本文给出了计算多对齿同时啮合轮齿接触线载荷分布的方法．并根据轮齿的啮合状态确定轮齿的最佳修形参数。利用作者编制的计算机程序研究了最佳轮齿修形参数对载荷分布系数的影响．     

风力发电机齿轮箱齿根弯曲疲劳寿命仿真技术与方法研究

为了正确评估齿轮传动系统齿根弯曲疲劳寿命,以风力发电机齿轮箱为研究对象,以轮齿的线性强度退化表征疲劳效应,建立系统寿命蒙特卡洛仿真模型。模型全面考虑轮齿强度的随机特性,由轮齿转动带来的系统结构时变特性,轮齿的强度退化引起的系统抗力时变特性,齿轮传动系统失效相关特性以及各特性之间的耦合作用。在模拟载荷谱下,分析750 kW风力发电机齿轮箱传动系统疲劳寿命的分布,得到各齿轮和齿轮传动系统的寿命分布参数。     

基于MASTA的单斜齿轮修形优化研究

为了研究不同修形方式对齿轮性能的影响,以一对单斜齿轮为例进行螺旋线修形、齿向起鼓及齿顶修形。采用MASTA软件对不同修形方案进行承载接触分析LTCA(Loaded Tooth Contact Analysis),计算各种方案下齿轮的传动误差、齿面接触应力及齿面载荷分布,并以齿面载荷分布均匀为优化目标,综合考虑传动误差及齿面接触应力,对齿轮进行螺旋线修形和齿向起鼓,并从修形量、修形长度和修形曲线3个方面进行齿顶修形优化,得到了特定工况、特定齿轮参数下的修形优化方案。研究表明：与未修形情况相比,最终优化方案在齿面载荷分布更均匀的情况下可使齿轮传动误差下降8.6%,且传动误差曲线更接近正弦曲线;最大齿面接触应力下降6.2%,齿面载荷分布系数KHβ由1.195 2降低至1.144 5;该修形优化方案有效地改善了齿轮的啮合性能。     

1.5MW风力发电齿轮箱箱体的有限元分析

建立了一套针对该类箱体的有限单元计算方法,获得了在重力载荷、轴承载荷、内齿圈轮齿啃合载荷单独作用下,齿轮箱体的应力分布规律和位移变化情况.该方法充分考虑了外界支承,将轴承径向力等效成余弦分布压力,箱体变形与刚度通过提取轴承座中截面位移曲线来观察.分析结果表明:重力引起的应力可以忽略;箱体支承没计应考虑内齿圈啮合引起的旋转效应;采用侧面支承的增速齿轮箱的输出侧轴承凸缘附近应采取局部补强措施,以抵抗弯曲变形;轴承载荷的大小和方向都对箱体的应力分布有重要影响.     

低噪声齿轮的动态共轭齿廓曲线(《高速齿轮的修形》之二)

高速齿轮传动装置,无论采用何种的标准齿形曲线(渐开线、摆线、圆弧或其它齿形),由于载荷作用下,轮齿材料弹性变形、温度变形以及系统变形等诸因素引起的综合变形量,使轮齿沿啮合线的静态共轭齿廓平     

船用透平齿轮齿宽载荷分布的计算及螺旋线修正_续

2.齿轮X 方向和Y 方向轴线不平行度对轮齿载荷分布的影响造成齿轮X 方向和Y 方向轴线不平行度的原因很多。除了制造精度不良外.还有以下几点:(1)齿轮箱热变形不均匀。主机隔热不良可能造成对齿轮箱体的局部辐射热,二级齿轮减速器的中间轴承座温度有可能比两端的轴承座温度高;(2)齿轮两端的支持     

多叶螺旋线圈强化平板太阳能集热器换热的试验研究

用铜丝制成双叶螺旋线圈和三叶螺旋线圈内插物,置于平板型太阳能集热器的流道内,以强化流道管壁与工作介质之间换热。在定热流条件下,进行了空管、扭带管、双叶螺旋线圈管和三叶螺旋线圈管的换热性能研究;在常温下进行了阻力试验。试验结果表明,双叶螺旋线圈管Nu数增加了68.4%～200.7%,阻力系数增加238.7%～794.6%;三叶螺旋线圈Nu数增加106.1%～272%,阻力系数增加470.8%～906.8%。通过回归分析给出了f和Nu与影响因素计算式。研究表明,双叶螺旋线圈管道和三叶螺旋线圈管道换热均优于空管和扭带管;三叶螺旋线圈管道比双叶螺旋线圈的换热效果更佳。     

基于“应变-载荷”模型的大型风电机组叶片载荷识别研究

为了解决风电机组运行过程中叶片载荷在线识别的难题,提出一种基于叶根应变测量的风电机组叶片载荷识别方法。开展叶片属性参数对应变单因素影响分析,基于此设计多因素联合影响正交试验,并利用回归分析来获取叶片属性参数与应变之间的关系模型。在回归分析过程中采用"显著性"判定进一步得到回归修正方程。充分考虑多重载荷的影响建立叶根应变与叶片载荷之间的关系模型。以某43 m长风电叶片为例构建出风电机组三维实体模型,利用CFD和ANASYS数值仿真软件对叶片上分布载荷和叶根应变进行分析。然后,将模型计算结果与有限元仿真结果进行对比分析,佐证所提出"应变-载荷"模型的可行性。     

加速热疲劳试验条件下内燃机受热件寿命的修正计算

本通过对低循环蠕变、高频载荷对为和低频疲劳的影响以及内燃机载荷谱对热疲劳寿命影响的研究，修正了无发动机加速热疲劳试验台的试验数据，并给出了实际内燃受热件寿命试验估算的修正公式。     

极端阵风条件下大型风力机叶片极限载荷研究

基于修正叶素动量理论,考虑经验修正、动态失速、动态入流等因素,结合叶片气动弹性响应问题,对大型风力机叶片在极端阵风条件下的极限载荷进行研究。以某MW级水平轴风力机叶片为例,研究动态失速、阵风上升时间、变桨速率等因素对叶片极限载荷的影响。结果表明,随着叶片大型化的发展,极端阵风条件下的极限载荷问题对风电机组的整机性能有较大影响。     

降低斜齿噪声的齿轮修形优化设计

本文讨论了渐开线斜齿圆柱齿轮的振动模型和修形模型．给出了降低斜齿轮噪声的齿轮修形方法和齿轮修形优化程序,并给出了一对斜齿轮副的计算实例．计算表明：正确、合理地选择斜齿轮修形量,可以有效地降低斜齿轮的噪声,但修形量过大反而会使噪声增加．     

Load sharing behavior analysis method of wind turbine gearbox in consideration of multiple-errors

Conducting a further analysis on loading sharing among compound planetary gear system in wind turbine gearbox, and making a meshing error analysis on the eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of wind turbine gearbox respectively. In view of the floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of all gears, this paper establishes a refined mathematical model of two-stage power split loading sharing coefficient calculation in consideration of multiple errors. Also obtains the regular curves of the load sharing coefficient and floating orbits of center gears, and conducts a load sharing coefficient test experiment of compound planetary gear system to verify the research results, which can provide scientific theory evidence for proper tolerance distribution and control in design and process.     

考虑齿圈柔性的风电行星轮系动态啮合特性研究

针对集中参数法难以考虑齿圈柔性而有限元法计算量大的问题,以风电行星轮系为研究对象在集中参数/有限元混合法基础上提出一种揭示内啮合齿轮副延长啮合现象的分析方法。首先采用集中参数法建立风电行星轮系的动力学模型,并求解获得动态啮合力;随后,运用有限元法建立行星轮系内啮合齿轮副的有限元模型,并开展静态接触分析从而获得内啮合齿轮副各啮合位置发生多齿啮合时的变形阈值;最后,将集中参数模型获得的动态啮合力施加在内齿圈有限元模型上计算出内齿圈的动态响应,并结合发生多齿啮合时的变形阈值,从而揭示在不同负载和支撑数量下内齿圈上多齿啮合的分布区域,获得接触应力和齿根应力,分析啮合齿对数量改变前后对应力的影响。结果表明：考虑齿轮柔性后,内啮合齿轮副会出现除理论啮合齿对外其他齿对相接触的现象;随着负载扭矩的增大,内齿圈上三齿啮合首先发生在支撑两侧,随后三齿啮合发生区域不断增加;当行星轮与内齿圈间的啮合由理论两齿啮合变为三齿啮合时,其齿面接触应力和齿根应力小于其在相同时刻只计入两齿啮合时的应力值。     

On the definition and effect of optimum gear microgeometry modifications for the gearbox of an offshore 10-MW wind turbine

This work develops an optimization algorithm for the definition of gear microgeometry modifications (MGM) on a gearbox belonging to an offshore 10-MW wind turbine. Subsequently, the impact of the gear microgeometry on the performance of gears and bearings is quantified: First, under rated load conditions and, second, accounting for the environmental conditions to estimate the long-term damage. To fulfil this task, a high-fidelity numerical model of the drivetrain is used, which meets the design requirements of the Technical University of Denmark (DTU) 10-MW reference offshore wind turbine. The optimization achieves a uniform distribution of the contact stress along the tooth flank, shifts its maximum value to the central position, and eliminates edge contact. These enhancements increase the gear safety factors. Nevertheless, the most significant improvement concerns planetary bearings, for which optimum gear MGM achieve a homogeneous share of the load among bearings. Moreover, deviations of the microgeometry with respect to the defined optimum are also addressed. In gears, lead slope deviations are counteracted by crowning modifications to restrain the increase of the load offset. Concerning planetary bearings, slope deviations can be beneficial or detrimental depending on whether they overload downwind or upwind planetary bearings, respectively. Finally, accumulated damage to planetary bearings after 20 years of service is assessed. Before MGM, results predict a premature failure of planetary bearings, while optimum MGM extend their predicted life above 20 years by achieving a reduction of the maximum accumulated fatigue damage by a factor of 4.4.     

Planetary gear load sharing of wind turbine drivetrains subjected to non‐torque loads

An analytical formulation was developed to estimate the load‐sharing and planetary loads of a three‐point suspension wind turbine drivetrain considering the effects of non‐torque loads, gravity and bearing clearance. A three‐dimensional dynamic drivetrain model that includes mesh stiffness variation, tooth modifications and gearbox housing flexibility was also established to investigate gear tooth load distribution and non‐linear tooth and bearing contact of the planetary gears. These models were validated with experimental data from the National Renewable Energy Laboratory's Gearbox Reliability Collaborative. Non‐torque loads and gravity induce fundamental excitations in the rotating carrier frame, which can increase gearbox loads and disturb load sharing. Clearance in the carrier bearings reduces the bearing stiffness significantly. This increases the amount of pitching moment transmitted from the rotor to the gear meshes and disturbs the planetary load share, thereby resulting in edge loading. Edge loading increases the likelihood of tooth pitting and planet‐bearing fatigue, leading to reduced gearbox life. Additionally, at low‐input torque, the planet‐bearing loads are often less than the minimum recommended load and thus susceptible to skidding. Copyright © 2014 John Wiley & Sons, Ltd.     

变风载下风力发电机齿轮传动系统动力学特性研究

根据风力发电机齿轮传动系统所处的由随机风速引起的复杂变工况环境,用自回归AR风速模型模拟实际风场的风速,获得了由随机风速引起的时变风载荷;采用集中质量参数法建立了传动系统的纯扭转动力学模型,求得了系统的固有频率和阵型;研究了传动系统在时变风载下的动态特性,求得了各齿轮的振动位移和各齿轮副的动态啮合力,为风力发电机传动系统的动态性能优化和可靠性设计奠定了基础。     

"蓝箭"号机车传动齿轮箱螺栓断裂的原因分析及改进措施

由于铝合金齿轮箱和钢制螺栓的热膨胀系数不同,所以在齿轮箱温度升高后要产生附加的温差载荷。此温差载荷是螺栓失效的根本原因,由此依据相关公式提出了改进措施。通过对联接螺栓的受力分析,确定了螺栓受脉动载荷作用时的安全系数。原联接结构的安全系数不满足要求,改进后的安全系数满足要求。改进措施是有效的,且为以后齿轮箱的设计提供了参考。