核电循环泵行星齿轮热弹流润滑研究

核电齿轮箱的良好润滑性能是核电循环泵可靠运行的重要保障,充分考虑齿面形貌和齿廓修形等因素对内/外啮合齿轮副的影响是准确评估其润滑特性的前提。建立典型工况下核电循环泵行星传动系统斜齿轮热弹流润滑模型,首先将斜齿轮副的啮合状态几何等效为圆锥滚子的接触问题,然后考虑斜齿轮接触变形和齿廓偏差,计算得到内/外啮合齿轮副接触区域不同位置的油膜厚度、承载压力、摩擦应力和闪温等参数。考虑齿面磨合作用,采用移动平均滤波方法对未经磨合的初始形貌进行光滑处理,分析了齿面形貌对润滑行为的影响,最后采取齿廓修形改善润滑特性。结果表明：粗糙度和齿廓修形均会对润滑特性产生明显的影响,齿面粗糙形貌会造成油膜厚度减小,进而影响其润滑特性,弱化润滑油膜的承载能力;通过齿廓修形可以改善齿轮啮合边界处的几何过渡,降低该区域的应力集中和表面温度,从而明显改善啮合线终端的润滑状态。     

渐开线蜗杆传动的动态接触分析

根据渐开线蜗轮、蜗杆齿面方程,运用MATLAB和SolidWorks对蜗杆、蜗轮进行三维建模,并将装配体导入ANSYS中进行动态接触分析.将模型导入动力学分析软件ADAMS中,研究蜗轮、蜗杆之间的啮合力变化.研究表明渐开线蜗杆副在啮合时不同位置应力变化较大,且蜗杆副正常啮合时的啮合力最大值出现在蜗轮、蜗杆轮齿初始啮合区...     

Parametric analysis of the end face engagement worm gear

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.     

Optimal design for an end face engagement worm gear with multiple worm-wheel meshing

To solve the problem for lacking a special mechanical transmission that could provide multiple outputs with high transmission efficiency and good lubrication in the modern industrial, a novel worm gear, named end face engagement worm gear, with multiple worm-wheel meshing is proposed for the first time. The essential parameters for the worm gear are optimized to enhance lubrication and meshing properties. Moreover, analysis of variance(ANOVA) is applied to determine the optimum levels and to determine the influence of parameters. The ANOVA results show that the novel end face engagement worm gear with multiple worm wheels provides high lubrication(the lubrication angle is more than 89°) and meshing performance(the induce normal curvature is less than 0.0002 mm~(-1)). The interaction between center distance and roller slant distance most strongly influences the lubrication angle(contributed 51.6%), followed by the parameters of center distance(contributed 25.0%), roller slant distance(contributed 16.4%), tooth angle of gear, gear ratio, and roller radius. In addition, roller radius most strongly influences the induced normal curvature(contributed 39.4%), followed by roller slant distance(contributed 15.2%), tooth angle of the gear(contributed 9.0%), center distance, and gear ratio. The proposed worm gear helps to enrich the no-backlash high precision worm drive and the optimal design method can provide a useful reference on performance improvement of other worm gear.     

乏油工况下斜齿轮热弹流润滑特性研究*

建立斜齿轮的乏油热弹流润滑模型,并讨论供油量、转速和齿面粗糙度对润滑性能的影响。结果表明:乏油工况下增大入口区供油量,润滑区的膜厚增大而摩擦因数、温升和次表面应力幅值降低;随着供油量增大,乏油润滑特性逐步趋于全膜润滑状态下特性;随着转速升高,润滑膜厚增大但幅度有限,相应温度场增大和次表面应力场增大;齿面粗糙度会使油膜压力出现剧烈的波动,在油膜压力峰位置的次表面会出现应力集中。     

渐开线齿轮轮齿表面磨损规律的理论与实验研究

用一对圆盘滚子试件在JP-DB1500型实验机上模拟一对齿轮啮合规律,对渐开线齿轮轮齿表面在干摩擦或润滑不良情况下的质量磨损及线磨损规律进行了理论和实验研究。结果表明:45#钢在不同热处理情况下,齿轮轮齿表面质量磨损量随载荷变化按指数规律变化;在润滑良好情况下,齿轮轮齿表面线磨损规律与干摩擦或润滑不良情况下磨损规律不同。通过实验研究,得到了齿轮轮齿表面磨损量的载荷因子。     

渐开面包络环面蜗杆特征建模研究

渐开面环面蜗杆的三维构建属复杂曲面造型,文章在环面蜗杆螺旋线参数方程建模的基础上,分析讨论了其与渐开面环面蜗杆螺旋齿面方程的对应关系,建立了渐开面包络环面蜗杆产型齿的特征模型。按此模型在MDT6.0三维绘图软件环境中实现了渐开面环面蜗杆的三维实体造型,并在进一步完成的"渐开面二次包络环面蜗杆副的虚拟实体"中,以断面图检验了其良好的啮合状态。所生成的实体模型具有给定参数的数字信息,可用于齿廓形状及特性分析,推动此类环面蜗杆的开发与应用研究。     

蜗杆传动的润滑分析

通过对蜗杆传动的润滑、效率与表面微峰接触载荷的分析,提出了一个新的蜗杆传动胶合失效判断因子,它综合考虑了润滑油膜破裂、微峰塑性变形与摩擦发热三种因素;基于Chittenden等的油膜厚度公式分析了蜗杆传动的油膜厚度,理论计算结果表明这一新的胶合因子在蜗杆传动润滑分析中具有指导意义,但对新的胶合因子仍需进一步实验验证。     

由蜗轮蜗杆减速机齿侧间隙引起的电梯轿厢冲击载荷分析

包括蜗轮蜗杆传动在内的齿轮传动,都必须确保一定量的齿侧间隙。该间隙位于齿槽与齿廓之间,即齿槽宽度必须大于齿廓宽度,以确保润滑及弥补热胀冷缩、安装误差等外界因素的影响。但正是由于该间隙的存在,会对于配备蜗轮蜗杆减速器的曳引电梯轿厢形成冲击载荷,从而对乘坐安全性造成影响。针对该冲击,进行了定性与定量的分析,并提出了减小或控制该冲击的方法。     

润滑和载荷状态对聚甲醛齿轮服役性能的影响

基于齿轮耐久性能试验台开展了一系列干接触/油润滑下POM(聚甲醛)-POM齿轮副承载能力试验,并测量了服役过程中的轮齿温度、磨损量、齿廓精度和齿面形貌。试验发现,POM齿轮失效形式与载荷和润滑方式有关。通过对齿面微观形貌和磨屑表征,确认干接触下POM齿轮主要磨损模式为黏着磨损与磨粒磨损,而油润滑下POM齿轮失效形式为接触疲劳失效。由于润滑油减少了齿面摩擦,降低了运行温度,延缓了齿面劣化程度,因此POM齿轮在油润滑下的承载能力明显提高。     

无侧隙双滚子包络环面蜗杆传动的啮合性能分析

基于空间啮合原理,建立了无侧隙双滚子包络环面蜗杆传动的啮合方程、接触线方程以及蜗杆的齿面方程,推导了该传动的诱导法曲率、自转角、润滑角及相对卷吸速度公式.基于MATALB开发了传动的啮合性能分析系统,分析了无侧隙双滚子包络环面蜗杆传动的滚柱半径、蜗杆喉径系数、滚柱偏距和齿周角等参数对传动啮合性能参数的影响.     

双圆弧齿圆柱蜗杆传动齿形参数的优化设计

本文以综合承载能力为目标函数,给出了双圆弧齿圆柱蜗杆传动齿形参数的优化设计方法。     

成形法加工新型环面蜗杆的原理性误差分析

新型环面蜗杆副由蜗杆、钢球和蜗轮构成,利用失配共轭技术,提高了其承载能力和适应性.在分析蜗杆廓面结构特征的基础上,给出了蜗杆廓面的准线方程,提出了基于准线的成形法加工方法,着重分析了加工过程中的原理性误差,推导出了廓面法向误差公式.以一组数值参数为例,绘制了齿形误差和齿向误差图,并在OpenGL平台上进行误差可视化处理.结果表明:成形法加工的蜗杆廓面齿形和齿向误差值较小,能够保证获得高精度的传动廓面.     

蜗轮稳态温度场及有限元分析

通过蜗杆传动的传热学、摩擦学及啮合原理的结合上进行研究,建立了蜗轮稳态温度场的数学模型。对对流换热系数和齿面输入的热流密度进行了分析,针对蜗轮齿面的几何特征和运动特征研制了相应的有限元程序,计算结果与实测结果基本一致。这为研究蜗轮的胶合失效和热弹流问题提供了依据。     

阀门电动装置蜗轮蜗杆精确建模研究

蜗轮蜗杆是阀门电动装置的关键传动部件,进行精确的实体建模是进行有限元接触分析的前提,而蜗轮的齿面是复杂的空间曲面,是建模的难点。通过蜗轮蜗杆的啮合关系得出蜗轮齿面啮合方程,运用Matlab编程求解蜗轮齿面方程得到齿面上的离散点,再通过Pro／E逆向反求得到蜗轮齿面,最终实现蜗轮的精确建模。另外通过Pro／E建立蜗杆模型并对蜗轮蜗杆进行装配,经检验装配后无干涉存在,结果表明该方法能够准确地建立蜗轮蜗杆实体模型。     

渐开线直齿轮瞬态微观热弹流润滑分析

考虑了瞬态效应、轮齿表面油膜温度场和轮齿表面纵向粗糙度等因素,对渐开线直齿圆柱齿轮的弹流润滑问题进行研究。载荷由双齿或单齿承担,根据实际载荷谱简化的轮齿载荷曲线,利用压力求解的多重网格法和弹性变形求解的多重网格积分法以及温度求解的逐列扫描技术,得到渐开线直齿轮瞬态微观热弹流润滑问题的完全数值解,讨论了轮齿间油膜的厚度、压力、温度沿啮合线的变化规律。数值计算结果表明,齿轮表面纵向粗糙度对轮齿间油膜的压力、膜厚、温升都有较大影响。考虑轮齿表面粗糙度后,油膜压力和温升明显增大,并随压力的增加而影响越来越显著,粗糙峰使油膜压力分布和温度分布产生振荡,轮齿表面的粗糙峰对摩擦因数影响较小,摩擦因数和最高温升在节点两侧最大。     

应用人工神经网络预测蜗轮齿面温度场

本文首先阐述了蜗轮温度场的数学方程 ;提出了一种基于人工神经网络的蜗轮齿面温度场预测方法 ,并得到了实验的验证     

复杂齿廓齿轮传动接触区的数值分析方法

对复杂齿廓进行离散,采用移动最小二乘法进行插值重构齿面,进而采用数值方法求解传动过程中接触区的形状及其变化.采用减半递推技术进行接触区搜索,计算效率高,收敛快.编写相关程序对非渐开线变厚齿轮和渐开线包络环面蜗杆两种复杂齿廓齿轮传动进行接触区分析,分析结果验证非渐开线变厚齿轮可以实现空间线接触而渐开线包络环面蜗杆传动承载能力强的特点.将分析结果与有限元分析结果和试验进行比较,证明本文方法的精确性和实用性.     

钢蜗轮摩擦副边界润滑状态判断及润滑油添加剂选择

使用Johnson和Hooke编制的润滑状态区域图,对实验所用的中心距为120mm钢蜗轮减速器摩擦副的润滑状态进行了计算与判断,根据润滑类型,合理选择了润滑油添加剂。     

Integrated wear prediction model for cylindrical gear with variable hyperbolic circular arc tooth trace under mixed elastohydrodynamic lubrication

Cylindrical gear with variable hyperbolic circular arc tooth trace (VH-CATT) is a new type of gear. Sliding wear is the main mode of the surface failure of multiple mechanical parts. Both the lubrication state and contact temperature considerably influence wear characteristics, which may aggravate the transmission performance of gear pairs. Wear, contact temperature, as well as lubrication states are jointly explored. Therefore, an integrated wear prediction model was proposed through taking into account flash contact temperature and surface roughness of VH-CATT cylindrical gears in mixed elastohydrodynamic lubrication. According to the equivalent ellipse contact model of VH-CATT cylindrical gears and tooth surface equation, normal curvature and velocity relations for VH-CATT cylindrical gears were observed, and the normal meshing force was obtained through the consideration of load sharing coefficients and quality grades. Flash contact temperature was estimated by using the literature. This study proposes analytical solutions for investigating how various surface roughness, operation, and geometric parameters affect asperity contact ratio (ACR), asperity contact pressure (ACP), flash contact temperature (FCT), as well as wear depth (WD) related to driving gears. ACR, ACP, FCT, as well as WD initially decrease and then increase from engaging-in to engaging-out processes. The minimum occurs at the pitch point. The WD declines as module, cutter radius, and rotational velocity increase while augmenting when surface roughness and torques increase. The maximum and minimum wear depths in driving gears occur at the dedendum and pitch point, respectively. Its overall wear is reduced by 23.16 % compared to the wear of spur gears. The results are valuable for the studies of tooth pitting, wear resistance, and fatigue life improvement for VH-CATT cylindrical gear. These studies can provide verification data and references required for engineering designs and VH-CATT cylindrical gear operations.