Mathematical model and bearing contacts of the ZN-type worm gear set cut by oversize hob cutters

The ZN-type oversize hob cutter for cutting of worm gears is investigated. The mathematical model of the ZN-type worm gear set is developed based on the cutting mechanism and hob cutter parameters. Influences of oversize hob cutter regrinding, worm-thread number and assembly errors on the bearing contacts and kinematical errors of the ZN-type worm gear set are investigated. A numerical example is given to demonstrate the bearing contacts and kinematical errors of the worm gear set.     

基于SolidWorks的链轮滚刀精铲刀的设计与加工

根据链轮滚刀的结构尺寸以及法向齿形，利用SolidWorks软件的三维特征造型功能，可以生成链轮滚刀基本蜗杆的三维立体图，从而在轴剖面上可以获得精确的轴向齿形，据此设计出链轮滚刀精铲刀的精确廓形，结合实例，介绍了链轮滚刀精铲刀的CAD／CAM的具体过程。     

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。       

加工齿轮滚刀齿形过程中如何提高齿形精度

针对阿基米德滚刀加工渐开线圆柱齿轮,用阿基米德造型的滚刀在刃磨滚刀齿形时,为了提高齿形精度,改变加工工艺和检测工艺,使用先进的"砂轮修正器"和"齿轮测量中心",缩短了设计和加工时间,提高了齿轮滚刀齿形磨制的效率,保证了滚刀加工渐开线圆柱齿轮齿形精度,使大于4模数的阿基米德滚刀齿形(A级﹑AA级)易于保证被加工渐开线圆柱齿轮的齿形精度。     

用球形滚刀滚切内齿轮

分析了球形滚刀滚切内齿轮的切削机理，探讨了齿槽断面的求解方法，用此方法在个人计算机上能高效率地绘制齿形创成图。分析表明，滚刀安装位置不影响滚切渐开线齿形。通过绘制齿形创成图，还可掌握各刀齿的切削负荷以及切屑的形状、厚度和长度。     

蜗杆压缩机星轮齿面分析及制造关键技术研究

分析了蜗杆压缩机啮合副中星轮齿面的组成,给出了包络面和轨迹面方程,讨论了星轮齿廓的径向滚切干涉。指出星轮齿廓无法采用精确展成加工获得,并提出了用极限轨迹面代替包络面的星轮加工方法,建立了星轮加工原理误差的计算方法和优化控制模型。理论研究及试验表明:提出的星轮齿廓加工方法,具有刀具易于制作、加工精度易于控制、生产成本低等优点。     

渐开线锥形齿轮滚削原理

基于空间双自由度包络运动理论 ,对渐开线锥形齿轮的滚削原理进行了深入的研究。首先通过分解滚切运动 ,由空间任意点相对速度的啮合接触条件 ,分析了滚刀作平移运动所包络出的产形齿条齿面 ,并求解了其主要参数。进而通过对滚刀、产形齿条及锥形齿轮三者之间空间几何关系的分析 ,从理论上阐明了锥形齿轮的滚齿加工原理并推导了机床调整参数的计算公式。理论和试验的结果表明 ,利用有径向进给运动的通用滚齿机可以实现渐开线锥形齿轮的正确加工     

基于鼓形蜗杆传动理论的内齿轮加工原理研究

针对目前内齿轮加工方法中普遍存在的精度低、效率低等不足,提出一种运用鼓形蜗杆刀具进行内齿轮连续分度的展成加工方法。以微分几何和啮合原理为基础建立鼓形蜗杆传动二次包络理论及鼓形蜗杆刀具齿面数学模型。分析内渐开包络母面重现的必然性及内齿轮加工共轭关系。研究鼓形蜗杆刀具齿面的轴向齿形特性及齿面根切规律,并给出刀具齿面根切的避免方法。应用虚拟中心距原理分析鼓形蜗杆刀具的粗加工工艺参数优化方法及其精确加工原理。该研究工作为内齿轮的高效高精加工提供了一种有效途径。     

数控端铣弧齿锥齿轮的刀背与轮齿干涉避免方法

在五轴数控机床上端铣加工弧齿锥齿轮时,为了避免中凹盘铣刀背锥面与对侧齿面发生干涉,提出了基于刀具和齿轮结构的干涉避免方法。通过确定加工轨迹上刀背圆锥面最突出母线与对侧齿面的位置关系,保证刀具背锥面沿进给方向的法曲率小于对侧齿面法曲率,优化确定刀具边缘厚度和背锥角,实现了端铣齿面时刀背不干涉对侧齿面。最后,以一对弧齿锥齿轮副的小轮为例,通过比较虚拟加工模型和理论模型,验证了所提干涉避免方法的有效性。     

基于椭圆的渐开线齿轮齿根过渡曲线研究

渐开线齿轮齿根过渡曲线是影响齿根弯曲应力的重要因素.为提高齿轮的弯曲强度,提出了采用椭圆曲线代替延伸渐开线的等距曲线,基于坐标转换原理,求出椭圆曲线方程.并采用30°切线法求出椭圆过渡曲线齿形系数和应力集中系数,与标准刀具加工的齿根曲线进行比较,结果表明采用椭圆过渡曲线可以使弯曲应力降低15％.根据齿形法线法,反求出获得该椭圆曲线的滚刀刀顶曲线,为滚刀刀顶设计和实际加工提供了理论依据.     

蜗轮飞刀齿廓曲线的算法及其计算机辅助计算和绘图

文中根据蜗轮滚刀加工蜗轮的原理，导出了基本蜗杆为阿基米德蜗杆时，蜗轮飞刀齿廓曲线上组成点的算法公式，并进行了通用Ａｕｔｏ－ｌｉｓｐ程序设计．应用ＡｕｔｏＣＡＤ命令绘制出飞刀齿形图。     

精磨双凸面蜗杆的一对螺旋蜗杆传动的计算机设计、啮合的形成和仿真(续)

作者们基于以下研究提出了精磨蜗杆的螺旋蜗杆传动的计算机设计和分析方法。1．滚刀的理论螺线表面是用一维面生成的。2．蜗杆表面与滚刀螺线表面相比齿廓和轴向为凸面。3．蜗杆的双凸面可局部承受接触和获得给定范围的传动误差的预先设计的抛物线函数。蜗杆传动的计算机设计可以显示和避免蜗杆齿面形成奇异点和齿棱。模拟双凸面蜗杆和蜗轮齿面的啮合和接触来确定支承接触轴线不对中和传动误差的影响。开发和应用数值解的计算机程序。数值计算实例说明所提供的开发原理。     

精磨双凸面蜗杆的一对螺旋蜗杆传动的计算机设计、啮合的形成和仿真

作者们基于以下研究提出了精磨杆的螺旋蜗杆传动的计算机设计和分析方法。1．滚刀的理论螺线表面是用一维面生成的。2．蜗杆表面与滚刀螺线表面相比齿廓和轴向为凸面。3．蜗杆的双凸面可局部承受接触和获得给定范围的传动误差的预先设计的抛物线函数。蜗杆传动的计算机设计可以显示和避免蜗杆齿面形成奇异点和齿棱。模拟双凸面蜗杆和蜗轮齿面的啮合和接触来确定支接触轴线不对和传动误差的影响,开发和应用了数值的计算机程序。数值计算实例说明所提供的开发原理。     

OPTIMUM DESIGN OF HIGH-SPEED RAILWAY LOCOMOTIVE TRACTION GEAR

ＯＰＴＩＭＵＭＤＥＳＩＧＮＯＦＨＩＧＨ－ＳＰＥＥＤＲＡＩＬＷＡＹＬＯＣＯＭＯＴＩＶＥＴＲＡＣＴＩＯＮＧＥＡＲＬｉＬｉｘｉｎｇ；ＷａｎｇＸｉｕｑｉ；ＨｅＷｅｉｄｏｎｇ；ＺｈａｏＷｅｎｚｈｏｎｇ；ＱｉａｎＹｕａｎｍｅｉ（ＤａｌｉａｎＲａｉｌｗａｙＩｎｓｔ...     

A 3D chip geometry driven predictive method for heat-loading performance of hob tooth in high-speed dry hobbing

High-speed dry hobbing is an emerging green technique for gear hobbing owing to its high productivity and environmental friendliness. However, severe friction occurs and heat instantaneously accumulates in the cutting region due to the adoption of high cutting speed and the lack of metalworking fluids, which causes serious hob wear. This investigation is concerned with the thermal performance and heat-loading quantitative method of hob cutter in high-speed dry hobbing. According to the multiple-edge and intermittent cutting behavior, the temporal dynamic characteristics of hob cutter are analyzed. Based on the complex 3D chip geometry produced in high-speed dry hobbing, the calculation method for heat-production (the amount of generated cutting heat) of hob tooth is proposed. Considering the coupling effects of heat conduction, heat convection, and heat radiation, the prediction model for heat-loading quantity (the bearing capacity of cutting heat) of hob tooth is developed. With the help of the developed method, the interrelation between the thermal performance of hob cutter and material removal volume, cutting conditions, coating material, respectively, are investigated. The predictive method developed in this work provides a methodology for process parameter optimization and hob cutter manufacturing of high-speed dry hobbing.     

基于SolidWorks的花键滚刀铲刀廓形设计与加工

分析花键滚刀铲齿工艺的难点 ,提出利用SolidWorks软件的三维特征造型功能方便地获得花键滚刀基本蜗杆轴向齿形的方法 ,据此精确地设计加工花键滚刀铲刀的廓形     

Surface finishing method for tooth flank of heat-treated surface-hardened small gears using a gear-shaped tool composed of alumina-fiber-reinforced plastic

High-accuracy gears are necessary to ensure the strength and silence of compact geared motors. Heat-treated surface-hardened small gears are employed in the reducer of a compact geared motor. The heat treatment causes distortion, which deteriorates the gear accuracy. To remove this distortion, surface-hardened small gears are rehobbed with a carbide hob. The rehobbing makes a tool mark on the gear tooth surface. This tool mark leads not only to strength deterioration of the tooth surface, but also vibration and noise. Therefore, a surface finishing method that eliminates the tool mark is required. However, it is difficult to finish surface-hardened small gears. This study proposes a tooth surface finishing method for a surface-hardened small gear. The method employs a gear-shaped tool composed of alumina-fiber-reinforced plastic (ALFRP) and a surface finishing device with an oscillation/traverse system. The proposed method was used in an experiment to remove the tool mark on the gear tooth flank of a surface-hardened small gear rehobbed by the carbide hob. The effectiveness of this method was verified. In addition, the processing mechanism of the ALFRP gearshaped tool was analyzed by observing the tool and the chips.     

A numerical study of the effects of cutter runout on milling process geometry based on true tooth trajectory

Cutter runout is a common phenomenon affecting the cutting performances in milling operations. To date, most of the milling process models considering cutter runout were established based on the circular tooth path approximation, which brought errors into the runout estimation. In this paper, a new approach is presented for modelling the milling process geometry with cutter runout based on the true tooth trajectory of cutter in milling. The mathematical relationship between the trajectories generated by successive cutter teeth with runout is analysed. The milling process geometrical parameters, including the instantaneous undeformed chip thickness, the entry and exit angles of a cutting tooth, and the ideal peripheral machined workpiece surface roughness, are modelled according to the true tooth trajectories. Numerical method is used to solve the derived transcendental equations. A simulation study of the effects of cutter runout on milling process geometry is conducted using the models. It was found that the change of cutter radius for a tooth relative to its preceding one is the most important factor in evaluating the effects of cutter runout.     

以蜗杆为母面的二次包络环面蜗杆传动

本文提出以蜗杆为母面，直接利用现有普通滚刀，在第一次包络时加工出蜗轮和蜗轮同开关的工具齿轮，实际只需加工出一个齿，做成沿螺旋线布刀的装配式刀具，这是一个更为经济而现有刀具不能加工的先进新方法。这种也能实现瞬时双线接触。