含侧隙齿轮副的动载荷分析

以振动理论为基础，提出一种考虑齿轮拍击振动的齿轮动载荷的数值计算方法。建立计算动载荷的齿轮冲击模型，在模型中考虑了齿轮正、反冲击时实际的啮合刚度，并给出啮合柔度的计算方法。分析在考虑静态传递误差、啮合刚度、侧隙、摩擦力及外部扭矩变化等多种激励时，作用在轮齿上的动态载荷以及整个齿轮上的综合动态载荷的计算公式。最后通过实例分析作用在轮齿上的动态载荷、综合动态载荷变化规律以及相关激励参数对动态载荷的影响。     

直齿圆柱齿轮啮合刚度的影响因素及其规律性

通过对齿轮啮合刚度计算公式的数学分析,确定了直齿圆柱齿轮啮合刚度的影响因素及规律性,指出渐开线直齿圆柱齿轮的啮合刚度与齿轮模数无关。采用新的当量齿形刚度公式的计算结果进一步验证了本文所得刚度影响因素及规律的正确性,并表明了当量齿形对刚度计算结果的影响。     

齿轮修形的优化设计与试验研究

通过对齿轮传动动态性能进行仿真研究,以一对直齿圆柱齿轮传动为例,研究了直线修形、抛物线修形和正弦修形,并优化设计了该齿轮传动取优动态性能时的齿廓修形曲线。通过比较修形齿轮和标准渐开线齿轮实测的振动加速度和噪声,证明了本优化修形设计方法对提高齿轮传动动态性能的突出效用。     

基于ANSYS/LS-DYNA的齿轮动力学接触仿真分析

针对渐开线直齿轮容易出现的载荷突变及噪声问题,需对齿轮进行齿廓方向的磨削修形。利用ANSYS/LS-DYNA中的APDL语句实现标准齿轮和修形齿轮的建模及动力学接触分析,并对分析结果进行比较,验证其修形的必要性。     

基于MATLAB与SolidWorks联合建模的渐开线圆柱直齿轮接触特性仿真分析

通过渐开线直齿轮齿廓方程在MATLAB中构建出渐开线直齿轮的点云模型生成精确地齿廓,将点云数据导入到SolidWorks中构建出齿廓精确的渐开线直齿轮副的三维模型;然后对渐开线直齿轮副进行理论接触应力计算,并对联合建模的齿轮副与参数化建模的齿轮副进行接触应力的有限元仿真分析和动力学仿真分析结果进行对比.结果表明:联合建...     

渐开线直齿轮修形的有限元分析与研究

针对不同修形曲线对齿轮修形产生不同效果的问题,首先推导出了渐开线参数方程和修形曲线的齿廓参数方程,然后应用Pro/E建立了标准渐开线直齿轮与修形齿轮的三维模型,最后利用ANSYS Workbench的瞬态动力学模块对其进行了有限元分析;通过仿真得出了渐开线直齿轮和修形齿轮在啮合过程中的齿面接触应力的变化曲线.研究结果表明,在齿轮传动时的单双齿啮合交替时及啮入/啮出时,Walker修形曲线较直线修形曲线具有更好的修形效果,但同时两种修形曲线都导致了齿轮重合度的降低,增加了单齿啮合区,为修形齿轮的设计提供了数值实验依据.     

改进Alexnet的滚动轴承变工况故障诊断方法

考虑齿面接触温升的影响，针对高速渐开线直齿轮动力学特性和润滑性能问题，建立摩擦动力学模型剖析齿轮润滑特性与动力学行为的耦合关系以及揭示油膜润滑机理。首先，建立含时变啮合刚度、齿侧间隙、传动误差的多自由度直齿轮弯-扭耦合动力学模型；其次，建立一维线接触瞬态混合热弹流润滑模型，通过整合得到含热效应的直齿轮摩擦动力学模型，利用龙格库塔法与多重网格法的联合迭代求解耦合系统的控制方程；最后，通过静态工况和动态工况数值计算结果的对比、摩擦动力学特性的分析以及温升的对比，证明了建立摩擦动力学耦合模型的必要性，为高速齿轮动态特性和润滑性能的改善提供分析方法。     

Effects of dynamic transmission errors and vibration stability in helical gears

Transmission error is an important reason for instability in helical gears. A six-degree-of-freedom dynamic model coupled flexional, torsional and axial motion of a helical gear transmission system, which includes time varying mesh stiffness, bearing supporting stiffness, mesh damping and backlash, is developed, after taking into account the dynamic characteristics and vibration responses of helical gear in three dimensions. Influences of involute contact ratio, bearing supporting stiffness, mesh damping and backlash on the dynamic transmission errors and vibration stability of the helical gear system are investigated using numerical simulation technique. The effects on dynamic transmission errors and stabilities by contact ratio, supporting stiffness and mesh damping as well as gear backlash are analyzed. The intrinsic relationship between above parameters and dynamic transmission errors and stabilities for helical gear system are presented. The stable and unstable regions under different parameters are given. The results in this paper can be helpful to the dynamic and stable design of a helical gear transmission system.     

齿轮传动正弦曲线修形的优化与试验研究

本文以一对直齿圆柱齿轮为研究对象,设计了齿轮动态性能最优时的齿廓修形曲线,并在齿轮动态效应试验台上进行实验。通过比较修形齿轮和标准渐开线齿轮的振动加速度和噪声,证明了本优化修形方法在提高齿轮传动动态性能设计中的突出效用。     

Dynamic analysis of involute spur gears with asymmetric teeth

New gear designs are needed because of the increasing performance requirements, such as high load capacity, high endurance, low cost, long life, and high speed. In some applications, such as in wind turbines, the gears experience only uni-directional loading. In these instances, the geometry of the drive side does not have to be symmetric to the coast side. This allows for the designing of gears with asymmetric teeth. In previous studies related to bending stress and load capacity, high performance has been achieved for gears with asymmetric teeth. These gears provide flexibility to designers due to their non-standard design. If they are correctly designed, they can make important contributions to the improvement of designs in aerospace industry, automobile industry, and wind turbine industry. At high operation speeds, there is always a concern of dynamic loads and vibrations of equipment. Therefore, there is a need to fully understand the dynamic behavior of gears with asymmetric teeth. Thus, the primary objective of this paper is to use dynamic analysis to compare conventional spur gears with symmetric teeth and spur gears with asymmetric teeth. The secondary objective is to optimize the asymmetric tooth design in order to minimize dynamic loads. This study offers preliminary results to designers for understanding dynamic behavior of spur gears with asymmetric teeth. For this study, a dynamic model was developed, using MATLAB, and used for the prediction of the instantaneous dynamic loads of spur gears with symmetric and asymmetric teeth. Furthermore, a 2-D three-tooth model was developed for finite element analysis. Fast Fourier transform was used for the frequency analysis of the static transmission errors. It is shown that generally, the dynamic factor, for spur gears with asymmetric teeth, increases with increasing pressure angles on the drive side. For asymmetric teeth, increasing the addendum leads to a significant decrease in the dynamic factor. The static transmission error, at the center of the single tooth contact zone, decreases with increasing pressure angle. The first two harmonics slightly increase with increasing pressure angle. It is further shown that the amplitudes of harmonics of the static transmission errors are significantly reduced when asymmetric teeth with long addendum providing high gear contact ratio close to 2.0 are used.     

直齿圆柱齿轮传动系统振动的动力学模型

通过对由齿轮、轴与轴承所组成的齿轮传动系统中弯曲振动、扭转振动和横向振动问题的分析,并考虑到齿轮质量偏心和轮齿啮合摩擦力对系统振动的影响,应用拉格朗日方程,建立了一对渐开线直齿轮传动系统振动的数学模型。得到了15自由度的时变系数振动微分方程组,为系统的振动分析奠定了基础。并给出一特定传动条件下的动态响应数值计算结果。     

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。     

Dynamic interaction between contact loads and tooth wear of engaged plastic gear pairs

This study investigates the interaction between the dynamic contact load and the tooth profile wear of POM and Nylon 66 plastic gear pairs. A dynamic model of a plastic gear pair is presented. This model incorporates the effects of position-varying tooth mesh stiffness, damping ratio, load sharing, tooth profile wear and temperature on the dynamic contact load. The tooth wear equation developed by Flodin and Andersson [Simulation of mild wear in spur gears. Wear 1997;207:16–23] is utilized to simulate tooth wear and tooth profile variation. The variation of the contact load generated by the cumulative tooth profile wear is simulated and examined. A computational algorithm is developed to simulate the interaction between a dynamic contact load and tooth profile wear. Numerical results demonstrate that the dynamic load histogram of an engaged plastic gear pair can change markedly due to tooth wear.     

Spur Gear Tooth Pitting Propagation Assessment Using Model-based Analysis

Tooth pitting is a common failure mode of a gearbox. Many researchers investigated dynamic properties of a gearbox with localized pitting damage on a single gear tooth. The dynamic properties of a gearbox with pitting distributed over multiple teeth have rarely been investigated. In this paper, gear tooth pitting propagation to neighboring teeth is modeled and investigated for a pair of spur gears. Tooth pitting propagation effect on time-varying mesh stiffness, gearbox dynamics and vibration characteristics is studied and then fault symptoms are revealed. In addition, the influence of gear mesh damping and environmental noise on gearbox vibration properties is investigated. In the end, 114 statistical features are tested to estimate tooth pitting growth. Statistical features that are insensitive to gear mesh damping and environmental noise are recommended.     

Geometric design of involute spur gear drives with symmetric and asymmetric teeth using the Realized Potential Method

The index gear drive potential is defined for the estimation of the quality of spur gear drives as a maximum contact ratio obtained at the contact of teeth profiles along the full line of action. In this paper, a new method is proposed for the geometric design of symmetric and asymmetric involute meshing in which the contact ratio of the gear drive is equal to its potential. This method is appropriate for the geometric design of spur gears with a small teeth number and is based on the generalized model of involute meshing. The gear drive potential is assigned as an input value, from which, after appropriate calculations, the geometry of rack-cutters, gears and involute meshing can be determined. Using the proposed method, the areas of the realized potential and the areas of the existence of involute gear drives are defined. In addition, many numerical examples are solved. In the cases of symmetric and asymmetric meshing, the minimum teeth number is obtained when the gear drive potential is larger than one.     

齿轮系统动态传递误差和振动稳定性的数值研究

建立了计及轮齿时变啮合刚度、啮合阻尼、支承刚度和阻尼的齿轮系统扭转-横向振动耦合的3自由度动力学模型。用数值仿真方法,研究了重合度、支承刚度、啮合阻尼和支承阻尼对齿轮动态传递误差和动力稳定性的影响。研究结论对于高速、精密齿轮传动的动力学设计具有积极意义。     

齿廓修形对齿面接触力影响的研究

简要介绍了齿廓修形的原理,给出了线性修形和二次曲线修形的表达式,利用齿轮分析软件建立了渐开线圆柱直齿轮的有限元接触分析模型,分析了修形前后齿间载荷分配及接触线上载荷分布情况,同时比较了不同修形量对修形后齿轮接触力分布的影响状况。本文能够为齿轮修形设计提供一定的理论依据。     

基于齿背接触刚度的高速斜齿轮瞬态振动特性

为了分析基于齿背接触刚度的高速斜齿轮瞬态振动放大特性,针对高转速瞬态工况下斜齿轮齿面啮合-脱啮-齿背接触的齿面实际承载接触状态,建立了同时考虑啮合时间与齿面振动位移耦合机理的斜齿轮动态啮合刚度。在细化考虑齿背啮合机理、基于齿背实际啮合刚度的模型基础上,进一步建立斜齿轮啮合型瞬态振动模型,并在此基础上展开不同齿侧间隙以及齿背接触对系统瞬态振动特性影响分析研究。搭建封闭功率流式斜齿轮瞬态扭转振动测试试验台,对基于齿背接触刚度的斜齿轮瞬态振动特性进行了验证。该研究具有较好的理论研究意义,有利于斜齿轮传动系统在航空传动、新能源传动系统上的应用推广,进一步提升高转速齿轮系统的瞬态振动噪声品质。     

Investigation of the Thermal Behaviour of Non‐metallic Curved‐Face‐Width Spur Gears

This paper describes a curved‐face‐width spur gear, specially designed for manufacture from non‐metallic materials. The benefits of this gear are the higher contact ratio, bending and Hertzian contact resistance, and greater tooth stiffness compared to standard spur gears. A modified geometry is proposed for the gear tooth, the height of which varies along the gear face width. Due to the reduction in tooth height, in sections away from the gear centre, lower sliding friction is expected, with consequences for the gear's thermal behaviour. The complex gear geometry makes the design of a die difficult; therefore the gears were cut on a milling machine, using a special kinematic generation process and related equipment. The tooth flank profile, an involute or near involute in sections away from the gear half‐width plane, as well as the flank surface quality determined by the single‐cutter tool used for gear manufacture, influence the meshing condition, and can be detrimental to the thermal behaviour of the gear. Experimental tests were carried out to examine the influence of load and speed on the temperature of the curved‐face‐width spur gears with modified geometry. The measured temperature of the non‐standard gear is further compared with the predicted temperature of plastic standard spur gears of the same specification.