基于包络特征的非圆齿轮齿廓计算方法研究

依据齿条刀具范成法加工非圆齿轮的原理,建立了计算机仿真加工中的刀具与齿坯间运动学模型;通过对仿真齿条刀具加工中齿廓形成过程的分析,提出了一种基于齿廓特征点的齿廓描述方法;根据齿廓的形成规律,提出了齿廓特征点、齿根圆、齿根过渡曲线和齿顶圆等全部齿廓数据的计算算法,并利用该算法编写了椭圆齿轮齿廓计算程序,该程序可直接用于线切割等数控加工设备加工。采用该方法设计加工出的椭圆齿轮已成功应用于所研制的插秧机分插机构样机及其试验台中,从而验证了该方法的可行性。     

基于包络特征的非圆齿轮齿廓计算方法研究

依据齿条刀具范成法加工非圆齿轮的原理,建立了计算机仿真加工中的刀具与齿坯间运动学模型;通过对仿真齿条刀具加工中齿廓形成过程的分析,提出了一种基于齿廓特征点的齿廓描述方法;根据齿廓的形成规律,提出了齿廓特征点、齿根圆、齿根过渡曲线和齿顶圆等全部齿廓数据的计算算法,并利用该算法编写了椭圆齿轮齿廓计算程序,该程序可直接用于线切割等数控加工设备加工。采用该方法设计加工出的椭圆齿轮已成功应用于所研制的插秧机分插机构样机及其试验台中,从而验证了该方法的可行性。     

逻辑齿轮的齿根过渡曲线设计及弯曲应力分析

建立了单圆角逻辑齿条刀具的齿顶圆半径的公式,得出齿顶圆半径与连接逻辑点的关系,并推出了两圆角逻辑齿条刀具的齿顶曲线方程。根据逻辑齿条刀具与逻辑齿轮之间相互啮合关系,求出逻辑齿轮齿根过渡曲线方程。通过Matlab编程求出逻辑齿轮齿廓上的点,拟合画出齿轮齿廓。建立了两种齿条刀具下的逻辑齿轮三维模型,运用Workbench对单齿啮合的逻辑齿轮进行静力有限元分析,得到逻辑齿轮的应力大小分布,结果表明单圆角齿条刀具对应齿根过渡曲线的逻辑齿轮弯曲强度较好。     

渐开线非圆齿轮的齿廓曲线数学模型

对于给定的非圆齿轮节曲线,借助于共轭齿条建立齿廓曲线的数学模型。根据渐开线齿轮齿廓成形原理,当共轭齿条分度线在非圆齿轮节曲线上作纯滚动,齿条的齿廓便在齿轮上包络出齿轮的齿廓。因此,首先建立了共轭齿条的数学模型和节曲线纯滚动模型,而后用啮合方程将这两个模型结合起来,经坐标变换后便在齿轮坐标系中获得了非圆齿轮齿廓曲线的数学模型。进一步用计算机图形仿真的方法获得椭圆齿轮的渐开线齿廓曲线图形,验证了该模型的正确性和有效性。该模型为非圆齿轮的加工刀具设计、数控加工程序设计以及轮齿强度分析等提供了基础。     

刀具齿廓形状的设计对齿根过渡曲线的影响

本文详细介绍了机械加工中常见的几种齿根过渡曲线,为了提高齿根弯曲强度根据建立的各种刀具刀顶圆角半径方程通过实例进行了几种过渡曲线的比较。最后通过齿轮刀具(齿轮型刀具和齿条型刀具)齿廓参数和齿条刀具齿廓参数推导出齿根过渡曲线方程,便于在有限元中建立准确的过渡曲线。     

一种非圆齿轮齿条机构的设计方法与分析

从传动比函数的角度出发,进行非圆齿轮齿条的设计,利用产形齿条是标准直齿条完成非圆渐开线直齿轮的齿廓设计,根据坐标变换完成齿条的齿廓设计。给定传动比函数,推导出相应的非圆柱直齿轮和齿条的节曲线方程;在MATLAB编程环境下进行齿廓的编制,进一步导入Pro/E中完成非圆齿轮齿条的三维模型建立,最后利用动力学仿真软件ADAMS完成非圆齿轮齿条的速度响应分析。所得到的齿条速度响应曲线基本与给定传动比函数的谐波曲线保持一致。     

K-H-V型少齿差减速器齿轮啮合可视化建模与分析

建立了少齿差减速器内齿轮副渐开线齿廓齿形和过渡曲线数学模型 ,综合考虑了齿条刀具和插齿刀加工内齿轮副两种情况下的齿根过渡曲线 ,采用可视化编程开发了渐开线少齿差行星传动齿轮啮合动态演示系统     

基于AutoCAD VBA的非圆齿轮实体建模

根据非圆齿轮齿廓的形成原理,建立了齿廓在形成过程中齿条刀具的运动模型.并用Auto-CAD的二次开发工具VBA,通过模拟非圆齿轮齿廓的形成过程,用实体的布尔运算生成非圆齿轮的实体模型.该模型可直接导入CAM软件中得到非圆齿轮的数控加工程序.     

刀具齿廓形状对齿轮齿根应力的影响研究

本文介绍了机械工业生产中不同齿廓形状刀具加工形成的齿根过渡曲线类型,并且通过刀具齿廓参数推导出齿根过渡曲线方程。在SolidWorks中建立了不同齿廓形状刀具加工形成的齿轮精确模型,使用Simulation对这些模型分别进行了有限元分析,从而研究刀具齿廓形状对齿轮齿根应力的影响。     

非圆齿轮的仿真加工及分析

非圆齿轮是指节曲线为非圆的齿轮,其结合了齿轮和凸轮的优点,能够实现变传动比运动,但其结构复杂,设计加工困难。为保证非圆齿轮模型的设计精度,采用解析法建立模型。首先,基于数值计算软件Matlab建立非圆齿轮的齿廓曲线,并导入至Pro/E软件平台,通过对非圆齿轮的齿廓曲线进行拉伸得到非圆齿轮的三维实体模型;其次,利用Pro/E软件中的Pro/E中的NC模块对建立的非圆齿轮三维模型进行线切割仿真加工和后置处理;最后通过查看log日志和过切检查,验证了加工程序的正确性和加工的可行性。结果表明:通过结合Matlab和Pro/E软件平台,有效地解决了非圆齿轮设计及加工困难的问题,为非圆齿轮的设计和加工提供了设计方法和理论依据。     

Numerical computing method of noncircular gear tooth profiles generated by shaper cutters

A simple and accurate numerical method was proposed for calculating the tooth profile of a noncircular gear. This method is directly based on the real gear shaping process, rather than deducing and solving complicated meshing equations used in the traditional method. The tooth profile is gradually obtained from the boundary produced by continuously plotting the cutter profile on the gear transverse plane. The key point of the method is picking up the graph boundaries. The relative position of the cutter profile on the gear transverse plane is determined by the given pitch line of the noncircular gear, parameters of the shaper cutter, and the shaping process data. In comparison with the traditional method, it is universal and is much more efficient and accurate, especially for noncircular gears, which have nontrivial pitch lines. Special problems in gear design and manufacturing, such as tooth pointing, undercut, and fillet interference, are included in the process. As an application example of the numerical method, a square internal gear is chosen from a new type of hydraulic motor with noncircular planetary gears, and the tooth profile of that gear is computed. The gear is successfully machined by electromagnetic discharge (EMD) using the resulting data.     

渐开线齿轮单齿啮合区的齿形系数

本文对范成法加工的渐开线圆柱齿轮，在单对齿啮合受载时，按轮齿危险截面形状（分平截面法和折截面法）、加工方法（分齿条刀类和插齿刀类），给出四组齿形系数的计算式。此式既可计算标准（或非标准）齿轮齿顶受载时的齿形系数，又可计算标准（或非标准）齿轮齿廓任意点受载时的齿形系数，还可计算具有非标准齿廓参数的渐开线齿轮任意点受载的齿形系数，为精确计算轮齿齿根弯曲强度提供了依据。     

基于非圆节曲线的轮齿程序设计

根据非圆齿轮节曲线方程,推导非圆齿轮轮齿的齿顶、齿根及齿廓的曲线方程,编程实现了非圆齿轮齿形的计算机辅助设计,减轻了人工设计的工作量,增强了非圆齿轮齿形设计的直观性,并为非圆齿轮传动的计算机辅助设计打下了基础。     

DESIGN OF NONCIRCULAR GEARS WITH DISCONTINUOUS PITCH CURVE

When the noncircular gear pair is applied to the continuously variable transmission (CVT) with gear, the transmission ratio function is discontinuous. In accordance with this unique characteristic, a new approach to design and analyze noncircular gears with discontinuous pitch curve is proposed. The design courses of various noncircular gear pairs with discontinuous pitch curve are unified based on the numerical algorithm of spline fitting and "fairing boundary condition". According to the particularity of discontinuous pitch curve, the rules and procedures for teeth distribution are recommended. It is explained in detail why the undercut is formed and how to manage the undercut based on meshing principle. In addition, the calculation formulas for each tooth profile segment are also derived. If the tooth profile data are calculated, the measurement and the incision process for noncircular gear can be conducted and the CAD simulation can be achieved easily. To ensure the continuity of the transmission, the transmission interference of the tooth which is located at the pitch curve joint point is managed by utilizing Bezier curve with CAD software. And the contact ratio of gear pair is obtained. The case study shows that this approach is successful and opens up a new way for the design of noncircular gear.     

修形直齿锥形齿轮啮合特性研究

为了避免直齿锥形齿轮发生边缘接触和降低对安装误差的敏感性,对小轮进行齿向弧线修形和齿廓抛物线修形.采用假想齿条的方法,模拟齿条与被加工齿轮的啮合运动关系,推导出齿轮齿面的数学模型,根据两齿面在啮合过程中的连续切触条件,建立了齿轮接触分析模型.仿真表明,修形后的直齿锥齿轮副,对安装误差的敏感性降低,且没有发生边缘接触,改...     

切顶齿轮滚刀的基准齿形

论述了切顶齿轮滚刀基准齿形的确定原则,分析了切顶齿轮滚刀齿根圆弧刀刃的展成齿形——切顶齿轮齿角过渡曲线的特征,提出了合理选择滚刀齿根圆弧半径的依据。     

双圆弧齿轮齿根应力的电测研究

本文的试验是用一片0.2毫米的电阻应变片在封闭流齿轮实验台上测量H-2型[5]双圆弧齿轮的齿根应力。测得了在不同载荷下受拉侧和受压侧的齿根应力沿齿长方向的分布曲线、“本齿”受载和“邻齿”受载所引起的齿根应力数值及应力和载荷的关系。可供双圆弧齿轮的强度计算及齿型设计的参考。     

Parametric modeling and contact analysis of helical gears with modifications

An approach for a mathematical model and contact analysis of helical gears including tip relief, root relief, end relief and longitudinal crowning modification was developed. First, tooth profile equations of non-modified involutes, tip reliefs, root reliefs and fillets were derived after applying gear principles and coordinate transformation to transverse cross section profiles of a rack cutter. Then the intersecting lines between different profiles were solved through by Gauss-Newton numerical method. Parametric modeling program of modified helical gears was obtained to automatically generate exact gear surfaces of tip reliefs, root reliefs, end reliefs and longitudinal crowning modifications via Matlab code. Subsequently, an example of helical gear pair in practical engineering was presented, and the solid model and finite element model with modification were established. Finally, the dynamic contact characteristic of helical gear pair was calculated by three-dimensional dynamic contact finite element method. It is expected that the proposed approach can be applied in analyzing the effect of modification on radiation noise prediction of gear system in further study.