Use of PLC module to control a rotary table to cut spiral bevel gear with three-axis CNC milling

CNC machining nowadays makes more use of "Mechatronics" increasingly. Combining numerical control with mechanic, electric, and data processing systems can lead to new methods of production. In recent years, the development of CNC has made it possible to perform nonlinear correction motions for the cutting of spiral bevel gears. In this paper, we attempt to manufacture the spiral bevel gear using a three-axis CNC milling machine interfaced with an additional PLC module based on traditional discontinuous multicutting method accomplished by using a universal milling machine interfaced with an indexing work head. This research consists of (a) geometric modeling of the spiral bevel gear, (b) simulating the traditional and our new nontraditional method using a CAD/CAE system, (c) process planning for CNC machining and PLC Programming, (d) experimental cuts with a three-axis CNC milling machine were made to discover the validity of the presented method. The results demonstrate that invented experimental cutting method of SBGs not only is less expensive than advanced CNC machining but also produces gears in a shorter time in comparison with the traditional cutting. Thereby, it is an economical method in manufacturing of SBGs.     

Influence of tooth modifications on tooth contact in face-hobbed spiral bevel gears

In this study the influence of tooth modifications induced by machine tool setting and head-cutter profile variations on tooth contact characteristics in face-hobbed spiral bevel gears is investigated. The concept of face-hobbed spiral bevel gear generation by an imaginary generating crown gear is applied. The modifications of tooth surfaces are introduced into the teeth of both members. The lengthwise crowning of teeth is achieved by applying a slightly bigger radius of lengthwise tooth flank curvature of the crown gear generating the concave side of pinion/gear tooth-surfaces, and by the variation of machine tool settings in the generation of pinion/gear teeth. The ease-off in the tooth height direction of meshing tooth surfaces is achieved by applying a head-cutter whose profile consists of two circular arcs, instead of a straight-line. The method of tooth contact analysis applied determines the path of contact, the potential contact lines, the separations along these lines, and the transmission errors. A computer program implements the method. By using this program the influence of the variation of machine tool settings and of head-cutter geometry on tooth contact is investigated and discussed.     

基于六轴数控铣齿机的点接触曲线圆柱齿轮加工仿真

点接触曲线圆柱齿轮是一种新型平行轴传动齿轮,用常规的机床和刀具难以完成其齿形的高效加工.利用六轴数控铣齿机和面铣式刀盘完成该齿轮的模拟加工.首先,根据该齿轮的成型原理,推导齿面的数学模型,求解齿面点云数据,基于点云数据在三维建模软件中构建齿轮实体模型;然后,在VERICUT中构建数控铣齿机和刀具,再编写齿轮加工的数控程...     

准双曲面齿轮的仿真加工新方法

以五轴联动CNC(computer numerical control)弧齿锥齿轮加工机床的概念模型为基础,提出了一种新的准双曲面齿轮齿面的加工仿真方法。在仿真过程中,将齿坯离散为一个同心圆族,把将刀具刃锥面简化为一个锥面。并以求解代表齿坯的同心圆和代表刃锥面的圆锥面的交点数值分析方法为核心算法,构建起了整个仿真系统的框架。解决了基于通用CAD(computer aided design)平台开发的切齿仿真系统无法直接获得齿面上指定点数据的弊端,为复杂齿面的仿真加工技术的发展提供了新的思路。     

DESIGN AND MANUFACTURE OF STRAIGHT BEVEL GEAR FOR PRECISION FORGING DIE BY DIRECT MILLING

In the manufacture of straight bevel gears, a precision forging method has been mainly used in recent years and the precision forging die has been usually manufactured using electric discharge machining. However, it is difficult to content the high productivity and low manufacturing cost using electric discharge machining because the gears are produced through a process of several steps. In this article, a design and manufacture of a straight bevel gear for a precision forging die by direct milling is developed in order to improve the productivity and manufacturing cost for the gear production. The tooth profile of a straight bevel gear generated by a quasi-complementary crown gear instead of a usual complementary crown gear is introduced. For this study, first the numerical coordinates on the tooth surface of the straight bevel gear were calculated and the tooth profiles were modeled using a 3D-CAD system. Afterward, the direct milling of the precision forging die of the straight bevel gear in the hardened state was carried out using a CNC milling machine based on a CAM process through the calculated numerical coordinates.     

曲齿锥齿轮的应用与发展

纵观曲齿锥齿轮的发展历史可以看出：其两种主要类型一弧齿和摆线齿，是由加工机床决定的。随着机械科学与其他学科的交叉，切削刀具与被加工齿轮之间的相对位置可以通过控制系统实现相当灵活的连续变动，曲齿锥齿轮的齿线和齿形应该将具有更大的选择范围。此外，应用计算机辅助技术可以充分挖掘传统加工机床潜在的强大的机械性能，使现有的廉价生产设备转变为高效、高可靠性、操作简便灵活的先进设备。     

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.     

螺旋锥齿轮大轮齿形误差的在机测量

为了在国产数控螺旋锥齿轮磨齿机上实现大轮齿形误差的在机测量,对大轮齿形误差的在机测量方法进行了研究。基于齿轮坐标系与机床坐标系之间的关系,建立了将齿面离散点坐标及法矢从齿轮坐标系转换到机床坐标系的方法。根据大轮的齿面几何特征,建立了大轮齿形误差的在机测量方法以及测量流程。根据在机测量得到的测球球心空间坐标,运用曲面拟合技术和最优化算法,计算了实际齿面相对于理论齿面沿各离散点法矢方向的齿形误差值。通过对比在机测量和齿轮测量中心的齿形误差测量结果,验证了螺旋锥齿轮大轮齿形误差在机测量方法的正确性。     

固定式端面弧齿联轴节的加工方法

为了在国产数控螺旋锥齿轮加工机床上实现端面弧齿联轴节的加工,对固定式端面弧齿联轴节的加工方法进行了研究。分析了端面弧齿联轴节的切齿原理和切齿方法,根据固定式端面弧齿联轴节的调整计算卡,建立了刀盘半径、刀齿顶宽、切削刃压力角、刀尖圆角半径的计算方法。基于端面弧齿联轴节的切齿原理以及国产数控螺旋锥齿轮加工机床的结构,建立了弧齿联轴节切齿加工机床调整参数的计算方法,给出了相关的计算公式并开发了端面弧齿联轴节设计、加工参数计算软件。在国产H350G型数控螺旋锥齿轮磨齿机上,基于软件计算得到的机床调整参数进行了实际的磨齿加工,通过实际的接触区检测和几何参数检测,验证了切齿加工参数计算方法的正确性。     

基于Pro／E的直齿锥齿轮参数化设计

在Pro／E中,根据机械设计中有关齿轮的设计原理,通过建立直齿锥齿轮中各变量与模数m、齿数z等基本设计参数的关系,实现直齿锥齿轮的参数化设计。更改齿轮的基本设计参数,便能自动生成新的齿轮三维模型,提高了设计效率。     

摆线齿锥齿轮加工中相关检验新方法

摆线齿锥齿轮可通过硬齿面刮削消除热处理变形,具有加工效率高、模数大、齿面硬的特点,所以非常适用于大型煤矿、冶金、运输等重型机械设备,针对大型摆线齿锥齿轮的生产实际提出并阐述了以更加直观和准确的实体建模方式对可能发生的刀盘干涉、齿面刮伤、槽底留埂、小齿轮根切或齿顶变尖进行检验.     

对角修形斜齿轮设计与数控磨齿研究

为了减小齿面振动,降低磨削误差,提出对角修形斜齿轮数控磨齿加工方法：通过设计对角修形曲线,经过3次B样条拟合为对角修形曲面;根据齿条展成渐开线齿面原理,建立平面砂轮磨削斜齿轮6轴联动Free-Form型数控磨齿模型,通过齿条与砂轮位矢等效转换,推导各轴运动关系;建立基于CNC机床各轴运动敏感性分析的齿面修正模型,各轴运动用6阶多项式表示,通过判断砂轮与齿面的接触状态,确定磨削齿面的误差,并分析各系数扰动对齿面误差的影响;以齿面误差平方和最小为目标函数,通过粒子群优化方法,得到机床各轴运动参数,该方法计算结果稳定且精度较高。通过算例表明：沿齿向方向压力角、螺旋角、展成角的微调可分别实现一定的对角修形加工;微调6轴联动机床各轴运动参数,可有效减小对角修形斜齿轮的磨削误差,通过机床运动敏感性分析验证理论和算法的正确性。     

螺旋锥齿轮数控加工中刀盘误差的补偿

在进行螺旋锥齿轮数控加工过程中,用直廓截形代替盘状铣刀刀刃理论截形所产生的偏差会影响螺旋锥齿轮齿面加工精度。针对该问题,分析了螺旋锥齿轮数控加工原理,并在此基础上建立了从刀刃到形成齿面的数学模型;依据空间啮合理论计算盘状铣刀刀刃实际截形,分析并建立了盘状铣刀刀盘半径偏差与齿面误差的关系;进一步推导出刀具实际截形误差的计算过程;最后根据螺旋锥齿轮的加工原理对刀具的误差进行了补偿计算,并对补偿结果进行了仿真实验验证,证明了该算法的可靠性。     

直齿锥齿轮齿形误差分析

直齿锥齿轮的齿形误差就是在齿形展开角范围内的基圆弧长最大误差,也就是渐开线上曲率半径误差,可据此得出齿形误差修正量的定量计算公式。     

Mathematical model and manufacture programming of loxodromic-type normal circular-arc spiral bevel gear

In this paper, loxodromic-type normal circular-arc spiral bevel gear is proposed as a novel application of the circular-arc tooth profile at the gear transmission with intersecting axes. Based on the principle of molding-surface conjugation, the study develops a mathematical model for the tooth alignment curve and the computational flow at the design stage to enable the generation of the tooth surface. Machining of the tooth surface is then carried out to determine the interference-free tool path of the numerical control (NC). Moreover, a pair of loxodromic-type normal circular-arc spiral bevel gears is manufactured on computer numerical control (CNC) machine tools. The proposed theory and method are experimentally investigated, and the obtained results primarily reflect the superior performance of the proposed novel gear.     

摆线齿锥齿轮铣齿机的运动及加工仿真研究

通过分析机械式摆线齿锥齿轮铣齿机的传动系统结构,推导了摆线齿锥齿轮加工时刀盘、摇台、产形轮及工件之间的相对运动关系,进而总结出摆线齿锥齿轮铣齿机各部分运动控制的一般规律;运用这一规律,在VERICUT数控加工仿真软件构建了摆线齿锥齿轮的加工仿真平台,实现了某摆线齿锥齿轮副小轮的加工仿真。     

Mathematical modeling for finishing tooth surfaces of spiral bevel gears using pulse electrochemical dissolution

Gears with a complex curve tooth, such as spiral bevel and hypoid gears, lack an ideal technique for the final finishing process. Pulse electrochemical finishing (PECF) is considered a promising method for surface finishing due to its micro-removal characteristics. A PECF system for spiral bevel gear (SBG) is established according to the generation of SBG tooth surfaces. An SBG (module, 12?mm; number of teeth, 38) is selected as the processing test piece, and mathematical models are developed for analyzing the characteristics of PECF. The influence of the experimental variables, including applied voltage, interelectrode gap, and finishing time, on the total removal thickness and surface roughness is discussed. The calculated values are found to be approximately consistent with the experimental values. The other parameters, including the concentration of electrolyte, tool rotational speed, flow rate of electrolyte, and pulse period, are also studied. Results show that the roughness of the SBG tooth surface is reduced from Rz 7.13 to 4.32???m. The precision of the SBG is also improved.     

基于UG结合PowerMILL在螺旋齿轮数控加工中的应用

研究了基于UG结合PowerMILL在螺旋齿轮的数控加工中的应用。讨论了螺旋齿轮的设计和数控加工技术,基于UG完成了零件的CAD设计,利用UG和PowerMILL的接口技术,将三维实体模型导入到PowerMILL中,完成螺旋齿轮的CAM加工编程,并以螺旋齿轮的四轴加工为例加以说明。     

伞形齿轮加工工装开发

在没有专业伞形齿轮加工设备的条件下,通过对伞形齿轮加工原理分析,结合数控车床刀架台和卡盘的位置特征,设计了一套数控车床加工伞形齿轮的工装装置。利用工装夹具的分度功能和数控车床刀架台的进给功能,解决了伞形齿轮轮齿的分度与铣削,实现了通用数控车床加工伞形齿轮。