内螺旋齿轮电火花加工的齿形误差分析

讨论内螺旋齿轮电火花成形加工中齿形精度的主要因素,重点分析极间电场强度对放电间隙的影响。指出电火花加工渐开线齿轮时,沿渐开线齿廓不均匀的电场强度分布而产生的齿形误差是电火花加工渐开线齿轮齿形误差的主要误差因素。改变齿廓曲率半径以形成均匀分布的电场强度,即采用修形齿廓曲线,是保证齿形精度的有效途径。     

修形齿轮端面重合度的计算

修形齿轮在工程中应用很广泛,修形可分为齿廓修形和齿向修形。其加工工艺通常为滚齿(滚刀为磨前滚刀)加磨齿。修形齿轮齿廓上通常带有修缘和挖根,渐开线长度与非修形齿轮不同,因此其端面重合度的计算方法也有所不同。通过探讨齿廓修形齿轮,研究了其端面重合度的计算方法。该方法基于Auto CAD二次开发,使用编制的VB程序实现。主要步骤分三步:首先,根据滚刀参数采用范成法原理仿真滚齿加工,得到粗加工齿形;其次,依据留磨余量计算出磨齿后渐开线,利用布尔运算得到磨齿后齿形;最后求出渐开线起始点、终止点及配对齿轮的有效渐开线起始点和终止点,并计算出端面重合度。最后与德国齿轮强度计算软件ST-Plus计算出的结果做对比,证明该方法的正确性。     

内齿轮齿根应力计算

本文推导了齿轮插刀按范成原理切制渐开线直齿内齿圆柱齿轮齿廓过渡曲线方程式,并由此方程式求解内齿轮齿形系数及齿根应力集中系数。其结果可用于内齿轮齿根应力的计算。     

插齿刀的齿高设计

渐开线齿轮生产中,插齿刀的应用仅次于滚刀.据国外统计,插齿机床约占齿轮机床的1/4.传统认为插齿刀加工是按展成原理、刀刃包络形成工件的渐开线齿形.按啮合原理,同一插齿刀可加工模数、压力角相同的任意齿数的标准齿轮和变位齿轮.插齿刀设计中,通常取原始截面变位为零,两侧分别为正、负变位.原始截面中,插齿刀分度圆齿厚、齿高分别对应被加工齿轮原始齿条齿厚、齿高.工件齿厚变化时,可调节插削深度,同一插齿刀加工同一规格工件,其变位系数也将变化,对应插削深度各不相同.为保证工件齿厚,插削深度为一不确定量.故工件齿根圆也千变万化,缺乏约束性,要求较严时,传统方法设计的插齿刀很难加工出合格工件.     

用标准齿轮滚刀滚切英制短齿渐开线花键

对英制短齿渐开线花键如用滚切法加工,一般工厂没有短齿渐开线花键滚刀,而标准齿轮滚刀却很容易得到。由于短齿渐开线花键的齿高大大小于标准齿轮的齿高,用标准齿轮滚刀去加工,加工出来的齿形实际上是移距修正齿轮的齿形,即用移距修正齿轮齿形的一部分来代替渐开线花键的齿形,当然齿形必然有误差,当齿深加工到图纸要求时,齿厚也必然有误差,采用     

LogiX齿轮的性能研究

LogiX齿轮齿形是由许多微段渐开线组成的一种异型功能齿廓，比常规标准渐开线齿轮具有诸多的优越性。本文通过有限元分析与计算，表明了LogiX齿轮的弯曲强度明显优于常规标准渐开线齿轮。同时，通过实际的啮合传动噪声测试实验，证明了Logix齿轮传动的噪声等啮合性能指标也优于常规渐开线齿轮。丰富新型齿廓理论，对今后推广应用新型LogiX齿轮奠定了理论和实践基础。     

模具渐开线齿形的电火花线切割加工

电火花线切割加工模具或齿轮渐开线齿廓之前,需先作曲线拟合,以便计算线切割编程数据.文章给出高精度的渐开线齿廓线曲线二点拟合法以及电火花线切割加工模具齿形和内齿精度简易检测方法.该方法对各种模具和圆柱齿轮的渐开线齿形加工均适用.     

温度变化对圆柱齿轮齿形的影响

通过对具有渐开线齿廓的齿轮温度场分析和热应力应变分析,指出标准渐开线齿轮在温度发生变化时,其实际齿廓曲线与理论曲线不相重合,表现为齿形的非渐开线特性,并给出此时的齿形误差。     

四齿差谐波齿轮传动采用渐开线齿廓的合理性证明

由于齿差系数的不同,四齿差谐波齿轮传动能否采用渐开线齿廓,不能利用以前的结论。本文研究了当柔轮采用渐开线齿廓时,与之共扼的刚轮采用渐开线对其理论齿廓进行拟合所造成的齿形误差的变化规律。通过与普通小模数渐开线圆柱齿轮传动的齿形公差进行比较,表明只要合理选择变位系数,刚轮就可以采用渐开线齿廓,这为在实际工程中研制四齿差谐波齿轮传动装置打下了理论基础。     

非对称齿廓齿轮弯曲疲劳强度理论分析与试验

为提高齿轮承载能力设计齿轮两侧压力角不等的非对称渐开线新齿形,推导双压力角非对称齿廓齿轮工作齿侧与非工作齿侧的渐开线齿廓方程和齿根过渡曲线方程,通过迭代计算和优化策略提出非对称齿廓齿轮疲劳强度解析法计算公式。编制生成非对称齿轮齿廓的参数化程序,在此基础上建立非对称齿廓齿轮有限元分析模型。通过解析法对不同压力角组合的非对称齿廓齿轮弯曲应力和危险截面位置计算得出,随着工作齿侧压力角的增大齿根最大弯曲应力逐渐降低,单齿啮合区向齿顶偏移;通过对有限元模型进行计算得出的结果与解析法一致,应用最小二乘法拟合出非对称齿廓齿轮齿根弯曲应力随工作齿侧压力角变化的计算公式。采用数控电火花线切割方法加工制造非对称与标准齿廓齿轮,在高频疲劳试验机上采用双齿脉动加载方法对其进行疲劳强度试验。试验结果表明,非对称齿廓齿轮在相同寿命下比对称齿轮极限载荷提高了50%,非对称齿廓齿轮的应力值变化趋势与前两种方法是一致的。     

Modeling and experimental verification of cutting forces in gear tooth cutting

Due to complex cutting edge profile of an involute cutter, calculations of chip width and consequently cutting force are quite problematical. This article presents a mechanistic approach in the prediction of cutting force components arising in the course of gear tooth cutting by an involute form cutter. To permit calculation of chip width (and so cutting forces), a discrete model is utilized and cutting force components are then derived using Kienzle approach. Moreover, several experiments are performed under different cutting conditions to prove the effectiveness and accuracy of the used method. The results have revealed that cutting force components can be predicted in form gear tooth cutting with a significant accuracy.     

基于VB程序的指形齿轮铣刀齿形计算

论述了齿轮的渐开线齿形铣削原理,推导出指形齿轮铣刀齿形计算步骤,开发基于VB程序的指形齿轮铣刀齿形计算程序,使用该程序能迅速精确地运算出各种渐开线指形铣刀齿形数据,使计算过程由繁变简,提高了齿轮刀具的设计精度和效率。     

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。     

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。     

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.     

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.     

The spherical involute bevel gear: its geometry, kinematic behavior and standardization

Bevel gear processing has diversified based on constant technical developments in forging, CNC cutting and hob design. Standardization of bevel gears is in higher demand than ever for different bevel gear systems that have different shapes and forms according to processing methods. With advantages such as excellent compatibility and the ability to absorb assembly errors well, the involute gear is referred to as the spherical involute tooth profile in bevel gear systems. This paper explains the geometrical characteristics and kinematic behavior of spherical involute gears. A spherical involute function is derived to effectively represent tooth profiles, and a common basic rack is developed using the equation of meshing to generate spherical involute gears. This study also analyzes the general characteristics of spherical involute gears and discusses the issue of bevel-gear standardization.     

高性能插齿刀的设计与试验研究

分析了现有标准插齿刀后角对齿形误差的影响,提出了误差均衡法,降低了插齿刀齿形误差,并应用于9°大后角插齿刀的设计有效地控制了插齿刀的齿形误差,并使之略低于标准插齿刀的齿形误差。通过对新型大后角插齿刀样刀与标准插齿刀切削对比试验和被加工齿轮精度测试与分析,验证了最佳齿形角修正算法理论的正确性。     

圆弧齿线圆柱齿轮的参数计算及选择

圆弧齿线圆柱齿轮是一种新型齿轮,１９８６年在布鲁塞尔第３５届国际新技术贸易展览会上展出。它的特点是：轮齿与其分度圆柱面的交线在分度圆柱面所展开的矩形中为圆弧;而且在齿宽中央截面内为渐开线齿形。本文推导了这种新型齿轮的齿面方程、重合度、压力角、齿宽系数计算公式;给出了其几何尺寸计算公式表;并论证了其特性参数：刀盘半径、齿宽系数、模数及齿数的选择原则。