Relation between wear and tooth width modification in spur gears

In this experimental study, width modification of a spur gear was investigated to fix instantaneous pressure changes along single meshing area on the gear profile. In this gear, variable pressure distribution caused by the single and double teeth meshing and the radius of curvature along the active gear profile was approximately kept constant by maintaining a constant ratio of applied load to the tooth width (F/b) on every point. Hence, Hertz pressure distribution along the gear profile was approximately equally achieved. Other factors affecting wear were kept constant during the experiment. The specimen used was made from AISI 4140 steel. Finally, the amount of wear in the teeth profiles between the modified and unmodified gears was compared. And wear depth of modified gear along the meshing area was almost uniform.     

修形直齿轮的啮合干涉与啮合间隙

修形直齿轮因误差因素在齿对的啮入和啮出位置会出现啮合干涉或啮合间隙。本文利用齿对的啮合变形与齿廓法向修形量、齿廓误差的关系,推导了啮合齿对在啮合线的啮入和啮出位置所存在的几何干涉或啮合间隙,得到了啮合重合度小于2和3的齿轮副啮合齿对的最大干涉量或间隙量的计算表达式,为分析修形直齿轮的啮合状态和修正齿轮修形参数奠定了基础。     

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.     

高齿弧齿锥齿轮的承载啮合仿真和动态性能试验

研究了高齿弧齿锥齿轮和普通弧齿锥齿轮的加载接触过程，对比了二者在载荷作用下的齿面载荷分布、齿面加载接触印痕和承载传动误差，计算了齿根弯曲应力。在台架试验台上测定了高齿弧齿锥齿轮和普通弧齿锥齿轮的噪声和振动量，实验证明高齿弧齿锥齿轮齿面载荷分布合理，弯曲应力较小，具有较低的噪声和较好的动态特性。     

高齿准双曲面齿轮的轮齿加载接触分析

给出了准双曲面齿轮齿加载接触分析的数学模型和加载接触分析的求解方法，计算了高齿准双曲面齿轮和普通齿准双曲面齿轮副的加载接触过程，对比了两种齿轮在不同工况和安装误差条件下的齿面印痕、齿面载荷分布、齿间载荷分配和承载传动误差，证明了高齿准双曲面齿轮副齿面载载体分布、齿间载荷分配和承载传动误差，证明了高齿准双曲面齿轮副齿面载荷分布和齿间载荷的分配合理，接触印痕受安装误差的影响较小，具有较高的强度和较好的动态特性。     

汽车门锁闭锁器小模数齿轮副接触有限元分析

汽车门锁闭锁器中的塑料齿轮在节线附近容易发生断裂,设计时需校核其强度。首先在CAXA中建立齿轮副模型,之后运用接触有限元方法,借助Ansys12.0有限元分析软件研究了齿轮副在一个啮合周期内的接触应力及结点位移的分布。得出了以下结论:齿轮副最大接触应力和结点位移都发生在节点啮合时;最大接触应力小于大小齿轮接触强度的极限值;相邻两啮合位置的接触应力相差较大时说明在此两位置之间发生了单对轮齿与双对轮齿接触的变换;对于塑料齿轮来说,当啮合位置是从齿顶向节点方向变化的单齿啮合时,齿轮副的最大接触应力总体呈减少趋势。为汽车门锁闭锁器中齿轮的设计提供理论参考。     

精确载荷分布下斜齿轮三维建模及弯曲应力分析

从范成法加工齿轮的原理出发,利用三维建模软件建立了渐开线斜齿圆柱齿轮的精确模型。根据齿轮啮合变形协调方程,利用线性规划法求解了齿轮副在各啮合节点的载荷分布情况,并计算了轮齿间的载荷分配率。利用有限元软件ANSYS计算了完整齿轮模型在啮合过程中的最大齿根弯曲应力,为齿轮弯曲强度校核提供了依据。研究结果发现,斜齿轮的最大弯曲应力有可能出现在多齿啮合的区域,这种现象与直齿轮有所不同。     

齿轮弯曲强度有限元精确分析方法研究

通过计算轮齿弹性共轭接触迹,确定齿轮在啮合过程中各个位置的压力角、齿廓接触长度以及接触位置等参数。并对ANSYS进行二次开发,制作了一个精确计算齿轮弯曲强度有限元分析的软件。运用此软件对相同参数的渐开线齿轮与点线啮合齿轮进行弯曲强度的有限元精确计算,得出点线啮合齿轮比渐开线齿轮弯曲强度提高11.7%的结论。     

摆线齿锥齿轮的产成原理及其产形面方程

根据加工中摆线齿锥齿轮、工作台及刀盘的相对运动关系,推导出变位情况下摆线齿锥齿轮产形面方程,据此可以导出啮合线、齿轮啮合面方程,对于进一步研究该类型锥齿轮的齿面特点和啮合特性及其加工有一定的参考价值.     

Modeling of helical gear contact with tooth deflection

The majority of gear tribological studies are made on spur gears. However, helical gears are generally used in industry, and their contact behavior deserves more attention to establish a realistic base for detailed friction, wear and life studies. This study focuses on the modeling of helical gear contact with tooth deflection. A calculation model for helical gear contact analysis is introduced. Helical gear surface profiles are constructed from gear tool geometry by simulating the hobbing process. The model uses three-dimensional finite elements for the calculation of tooth deflection including tooth bending, shearing and tooth foundation flexibility. The model combines contact analysis with structural analysis to avoid large meshes. Tooth foundation flexibility was found to have an essential role in contact load sharing between the meshing teeth, whereas contact flexibility plays only a minor role. The capability of different local contact calculation methods was also studied.     

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。     

基于温度场的螺旋锥齿轮啮合热特性分析

根据螺旋锥齿轮啮合方程,采用“自底向上”的实体建模方法和八节点六面体等参元,建立其三齿的有限元分析3D模型;采用热传导理论,求解了螺旋锥齿轮本体稳态温度场。由此,对热和结构两个物理场进行耦合,仿真分析了啮合过程热应力和热变形。实例分析结果表明,螺旋锥齿轮副多齿啮合时其中一个齿的啮合中心稳态温度较高,热应力最大处在齿根部位,靠近啮合中心的齿顶部位的热变形最大;由于结构、材料特性等多因素影响,最大热应力和热变形部位不与最高温度点重合。这些为螺旋锥齿轮的设计制造和使用提供了一定依据。     

高齿准双曲面齿轮的研究

研究基于局部综合法的高齿准双曲面齿轮ＨＦＴ法切齿参数的设计,给出用ＨＦＴ法加工准双曲面齿轮副的齿面接触分析方法,并在此基础上,比较了普通齿和高齿２种准双曲面齿轮副的传动误差曲线和啮合区。结果表明,高齿准双曲面齿轮副具有较好的啮合性能。     

旋转齿轮瞬时接触应力和温度的分析模拟

建立了高速齿轮传动轮齿瞬时接触温度的分析方法和模型;采用赫兹接触理论和有限元接触分析方法分析了标准渐开线齿廓和齿顶修形齿廓的齿面接触压力;研究了啮合过程中轮齿的相对滑动速度和齿面摩擦因数以及摩擦热流密度的计算方法;建立了轮齿本体温度的有限元温度分析模型;计算了轮齿接触面的瞬时温升;分析了标准和齿顶修形渐开线齿轮的轮齿本体温度和瞬时接触温度及相关因素对它们的影响。     

Study on development of polyamide gears for improvement of load-carrying capacity

In polyamide based gears, thermal damage of the gear tooth surfaces occurs during gear meshing due to accumulated heat in the tooth body. In the experimental study reported in this paper, polyamide gear teeth have been modified in order to distribute the generated heat on the tooth surface by means of drilled cooling holes at different locations on the gear tooth body. The main aims of this paper were to study the effect of cooling holes on the accumulated heat on the tooth surface and on the measured wear. It was shown that the drilled cooling holes on the tooth body decreased the tooth surface temperature and led to an increase in the load carry capacity and improved wear resistance. Geometrically modified gears have showed an improved service life and a decreased surface temperature.     

偏心渐开线齿轮传动的不等分模型及其数值解法

针对等分模型下配对齿工作齿廓出现实际啮合不会发生的齿廓交叉或者分离现象,根据渐开线齿廓啮合几何关系,提出一种不存在假设误差的偏心渐开线齿轮传动不等分模型,以奇数齿偏心齿轮传动为例,给出不等分模型数值求解的完整算法。根据内公切线与两轮配对齿工作齿廓的交点数不同,啮合点搜索算法能处理任意转角关系下连续转动的4种情形,能正确产生7种不同的配对结果。计算结果表明,几何中心连线与内公切线段的交点不相互等分两线段,啮合点不总是在内公切线上,和轴心距大小无关。当基准齿工作齿廓坐标点数为5 000点时,啮合点搜索的坐标控制精度可达到0.001 mm,转角误差精度可达到0.001°,计算方法可以得到非常精确的转角关系,可以为偏心齿轮传动的准确分析和优化设计提供依据。     

齿根动态应力分析

齿根应力分析是齿轮设计的一个主要问题,啮合过程中齿根应力分布特性是衡量齿付传动性能的主要指标。本文讨论了直齿圆柱齿轮在啮合过程中有关轮齿刚度、齿面载荷分配、以及齿根应力的计算方法。并通过实验进行分析。同时对修形齿轮与非修形齿轮作了对比分析实验。证明对重载齿轮进行修形能有效地改善齿根应力特性。     

新型环面渐开线齿轮齿面生成和几何特性研究

环面渐开线齿轮是一种对安装误差不敏感,无须修形就具有良好啮合性能,并且加工便捷的新型齿轮。根据环面渐开线齿轮的加工原理,从产形齿条的齿面方程出发,推导了凸环面渐开线齿轮和凹环面渐开线齿轮的完整齿面方程;利用MATLAB编程计算出环面渐开线齿轮齿面上点的三维坐标值,生成了精确齿面,并在Pro/E中建立了齿轮的实体模型;基于齿面数学模型,通过计算仿真对环面渐开线齿轮的根切与尖化现象进行了分析,获得了环面渐开线齿轮的根切界限曲线、尖化初始点以及不发生根切与尖化现象的最大齿宽;根据已生成的齿面进行有安装误差条件下的齿轮接触分析,证明了环面渐开线齿轮对安装误差不敏感。       

直齿轮齿廓修形的实验研究

对3种不同齿廓修形参数的渐开线直齿轮进行了振动和噪声的传动实验研究。实验结果表明，按下述原则设计的修形直齿轮具有较好的减振降噪效果：不计误差的理论设计修形齿轮的最大综合修形量应能消除含误差齿廓轮齿在啮入和啮出位置产生的几何干涉，理论设计修形齿轮的静态传动误差应保持最小的幅值变化。     

裂纹齿轮啮合刚度的劣化特性

基于轮齿的变截面阶梯悬臂梁假设,综合考虑轮齿弯曲、基础变形、接触变形等因素,首先,建立了健康齿轮时变刚度的计算模型,利用解析法与有限元仿真对比研究,获得了健康齿轮啮合刚度的分布曲线;然后,基于线弹性断裂力学前提下的齿根裂纹扩展路径,建立了包含不同尺度裂纹的有限元模型;最后,针对不同长度的裂纹齿轮,计算获得了1.5个啮合周期内的刚度曲线,从而建立了裂纹尺寸与刚度劣化特性的影响关系。通过对比单、双齿不同啮合区内的劣化规律,表明单齿啮合区由于单齿承载,其劣化程度明显高于双齿啮合区。此外,啮入阶段与啮出阶段的双齿啮合区劣化特性也存在一定差异。