DIRECT DIGITAL DESIGN AND SIMULATION OF MESHING IN WORM-GEAR DRIVE

A direct digital design method (DDDM) of worm-gear drive is proposed. It is directly based on the simulation of manufacturing process and completely different from the conventional modeling method. The loaded tooth contact analysis (LTCA) method is analyzed, in which the advanced surface to surface searching technique is included. The influence of misalignment errors and contact deformations on contact zone and transmission error (TE) is discussed. Combined modification approach on worm tooth surface is presented. By means of DDDM and LTCA, it is very convenient to verify the effect of worm-gear drive's modification approach. The analysis results show that, the modification in profile direction reduces the sensitivity of worm-gear drive to misalignment errors and the modification in longitudinal direction decreases the TE. Thus the optimization design of worm-gear drive can be achieved prior to the actual manufacturing process.     

Kinematic errors on helical gear of triple circular-arc teeth

Two imaginary skew rack cutter curves with stepped triple circular-arc teeth are presented in this paper. A helical gear pair that includes the gear and pinion surfaces was generated by using two matched imaginary skew rack cutter surfaces. The mathematical models of the helical gear pair with stepped triple circular-arc teeth were developed based on theory of gearing. With the use of these models, the analysis of kinematic errors can be illustrated and evaluated by computer programming and tooth contact analysis (TCA). The assembly errors used had several kinds: ideal assembly errors, vertical misalignment angles, horizontal misalignment angles, manufacturing errors of helical angles, and center distance deviation. TCA revealed that the sensitivity of horizontal misalignment angles was lower than that of manufacturing errors of helix angles but higher than that of vertical misalignment angles.     

Parametric analysis of the end face engagement worm gear

A novel specific type of worm drive, so-called end face engagement worm gear(EFEWD), is originally presented to minimize or overcome the gear backlash. Different factors, including the three different types, contact curves, tooth profile, lubrication angle and the induced normal curvature are taken into account to investigate the meshing characteristics and create the profile of a novel specific type of worm drive through mathematical models and theoretical analysis. The tooth of the worm wheel is very specific with the sine-shaped tooth which is located at the alveolus of the worm and the tooth profile of a worm is generated by the meshing movement of the worm wheel with the sine-shaped tooth, but just the end face of the worm(with three different typical meshing types) is adapted to meshing, and therefore an extraordinary manufacturing methods is used to generate the profile of the end face engagement worm. The research results indicates that the bearing contacts of the generated conjugate hourglass worm gear set are in line contacts, with certain advantages of no-backlash, high precision and high operating efficiency over other gears and gear systems besides the end face engagement worm gear drive may improve bearing contact, reduce the level of transmission errors and lessen the sensitivity to errors of alignment. Also, the end face engagement worm can be easily made with superior meshing and lubrication performance compared with the conventional techniques. In particular, the meshing and lubrication performance of the end face engagement worm gear by using the end face to meshing can be increased over 10% and 7%, respectively. This investigate is expect to provide a new insight on the design of the future no-backlash worm drive for industry.     

机床误差对圆弧齿线圆柱齿轮齿面误差影响规律的理论研究

机床误差是导致圆弧齿线圆柱齿轮齿面误差的主要原因,研究机床误差与齿面误差之间的关系将为机床加工参数反求、齿面误差修正等提供理论依据。基于圆弧齿线圆柱齿轮成型原理建立了齿轮机床结构模型,建立了机床坐标系体系。通过齿坯和刀盘位置误差、刀具形状误差对机床整体误差进行描述,基于啮合原理推导了理想情况下和包含机床误差的齿面方程。研究了齿轮误差曲面计算方法,采用二阶近似曲面和齿面平均误差影响系数分析不同机床误差下误差曲面,研究机床误差对齿面误差的影响规律。通过实例分析了被加工齿轮几何参数不变时和变化时,机床误差对圆弧齿线圆柱齿轮凹齿面误差影响规律。     

近似面齿轮传动的齿面拓扑修形主动设计

为了提高面齿轮的磨齿效率,采用不做齿向进给运动的大半径盘形砂轮磨齿得到的面齿轮具有近似齿面,然而该近似面齿轮与双向修形小轮的啮合性能不够理想.因此进一步通过啮合理论重新构造小轮齿面,并根据预设的啮合性能对该新构造的小轮齿面进行拓扑修形设计,以控制近似面齿轮传动的啮合性能.小轮的拓扑修形齿面采用盘形砂轮局部点共轭法磨齿加工,建立了小轮拓扑修形齿面与加工参数之间的线性方程.用实例说明了所提方法的应用,齿面接触分析结果与给定的啮合性能基本一致.     

蜗杆砂轮磨齿加工参数优化

以蜗杆砂轮磨削加工20CrMnTi齿轮为研究对象,选择均匀设计试验法,研究磨削参数（砂轮线速度vs、砂轮沿齿轮轴向进给速度vw、磨削厚度ap）对齿面粗糙度的影响。采用二级逐步回归方法建立磨削参数与齿面粗糙度的回归模型,构建了以加工效率、齿面粗糙度为多目标的优化模型,采用粒子群优化算法对磨削参数进行了优化。试验结果表明,使用优化后的磨削参数加工可以提高加工效率、减小齿面粗糙度。     

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。     

变位非正交面齿轮副小轮齿向修形轮齿接触分析

建立了变位非正交面齿轮的加工坐标系和啮合坐标系,推导了变位小轮及变位非正交面齿轮的齿面方程,计算得到了面齿轮数值齿面,分析了变位对非正交面齿轮齿宽的影响。在变位的基础上研究了对小轮进行齿向鼓形修形,而面齿轮不修形的修形方式。分别对未变位、变位、变位加小轮齿向修形的三种非正交面齿轮传动形式进行考虑安装误差的轮齿接触分析。研究表明：随着变位系数增大,非正交面齿轮最小内半径、最大外半径及极限齿宽均减小;变位不影响非正交面齿轮副的接触规律;小轮齿向修形能降低接触轨迹对安装误差的敏感性,会引起幅值较小的直线型传动误差。     

弧齿锥齿轮的接触特性研究

根据弧齿锥齿轮的加工原理，建立了弧齿锥齿轮的切齿共轭方程，在考虑误差和支承刚性的条件下，对锥齿轮的接触特性进行了研究，并分析计算了误差及支承刚性对齿轮副的接触印痕和运动曲线的影响。     

Study on precision grinding of screw rotors using CBN wheel

With increasing demands for high-speed and high-precision machining technology, CBN shape grinding is an effective means in the field of precision machining for screw rotors. Aiming at the high precision machining of screw rotors, a mathematical model for the axial profiles of the CBN wheel for machining screw rotors is developed based on theory of gear engagement. Small electroplated CBN wheel is firstly used to grinding screw rotors. Taking the backlash of screw rotors and the coating thickness of CBN layer into consideration, the modification of the base body of the wheel shape is introduced into the design of CBN wheel. For reducing the tooth profile errors of screw rotors induced by mounting errors and wears of CBN wheel, a mathematical model of the error analyses is established and the influence curves of the profile errors affected by mounting errors and radius error of grinding wheel are proposed. The electroplated CBN wheels for the screw rotors are made to verify the validity and effectiveness of the presented method and the machining experiments were performed. Results of this study reveals that the method proposed in this paper can be used as the precision grinding of screw rotors.     

采用包络法计算刀具刃口齿形

为了提高刀具的齿形精度,采用包络法计算刀具刃口齿形。根据二次包络环面蜗杆成型原理,提出了用包络法建立蜗轮齿面数学模型的方法,推导了蜗轮在中间平面齿形方程,即刀具刃口齿形方程,并利用MATLAB软件绘制出刀具刃口齿形。基于逆向工程的思想,用Pro/E软件建立了蜗杆三维模型。结果表明:蜗杆齿槽在轴向截面齿形与包络法计算得到的刀具刃口齿形一致。     

采用碟形砂轮的斜齿面齿轮磨齿技术研究

为了制造出高精度硬齿面斜齿面齿轮和获得抛物线传动误差并改善啮合性能,对采用碟形砂轮加工双向修形的斜齿面齿轮的磨齿方法进行了研究。设计了渐开线失配的碟形砂轮齿面,分析了碟形砂轮磨削斜齿面齿轮的展成原理,根据展成原理和用渐开线失配的碟形砂轮并改变砂轮的运动,推导出双向修形斜齿面齿轮的齿面方程。给出了双向修形斜齿面齿轮的齿面计算和接触分析实例,结果表明:理论齿面的最大齿面误差为5.98×10-4μm,采用碟形砂轮加工双向修形斜齿面齿轮的磨齿方法是可行的,获得了斜齿面齿轮抛物线传动误差,避免了边缘接触并改善了斜齿面齿轮的啮合性能。     

高重合度摆线内齿轮副齿面接触强度研究

合理的齿轮强度计算是实现齿轮结构设计及优化、保证留有适当裕量的基础。高重合度摆线内齿轮副同时参与啮合的轮齿对数较多,齿根弯曲应力很小,所以只需考虑齿面接触强度问题。基于改进能量法和赫兹弹性理论,推导了理想条件下该齿轮副的时变啮合刚度、齿间载荷分配和齿面接触强度计算模型。鉴于共轭齿廓节点处曲率半径为零,研究了节点附近不参与啮合的齿廓修形区域优化问题,在此基础上,通过将齿轮加工中产生的各种误差及侧隙转化为理论齿廓公法线上的偏移量,分析了不同加工误差对承载特性的影响程度,并在ABAQUS中进行了加载接触有限元分析验证。结果表明,该齿轮副对加工误差（侧隙）非常敏感,即对精度要求很高,为齿面接触强度计算和误差控制提供了技术支持。     

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。     

混凝土运输车搅拌筒减速器齿轮修形方法的研究

简要介绍了齿轮修形的原理,描述了齿廓修形和齿向修形参数选择原则与确定方法.运用MASTA软件建立混凝土运输车搅拌简减速器的完整有限元模型,并进行了齿轮修形的仿真分析和计算.比较了齿廓修形前后啮合线上的载荷波动情况,考察了不同修形参数对轮齿载荷分布和齿轮啮合性能的影响,获得了较为理想的综合修形效果.最后通过齿轮接触印痕试验验证了齿轮修形仿真分析方法的可靠性.     

A profile dressing method for grinding worm used for helical gear with higher order modification profile

In the case of generation grinding of the higher order modification gear surface, there are main problems such as difficulty in solving the 3D meshing equations and complexity of expressing the profile of grinding worm. In this study, an indirect generating method is proposed to calculate the profile of grinding worm by applying a virtual rack-cutter (VRC) between the grinding worm and the work gear. The grinding worm dressing experiments were processed by using a ball-nose diamond wheel. According to the results of tooth profile deviation measurement, the tooth profile modification curve is coincident with the predesigned modification curve. Compared with the gear without modification, vibration experiments show that the basic frequency, double frequency, and triple frequency decreased simultaneously, which verified the correctness of calculation and effectiveness of dressing for the profile curve of the grinding worm.     

精密加工变齿厚内齿轮插齿刀设计

针对标准插齿刀通过斜插法或插削角优化法难以实现变齿厚内齿轮高精度加工的问题,提出了一种精密加工变齿厚内齿轮的专用插齿刀设计方法。该插齿刀齿廓方程同时包含刀具几何参数和插削角工艺参数。基于啮合原理推导了刀具齿廓方程,建立了插齿刀切削刃数学模型,给出了插齿刀切削刃参数优化流程。对比分析了不同加工方法的齿形误差,研究了设计参数变化对齿形误差的影响规律。结果表明,所提出的方法在各种设计参数下均能有效减小齿形误差,设计出的刀具按优化倾角做直线插削即可实现变齿厚内齿轮的精密加工,无需对机床进行改造,易于推广。     

有误差的螺旋锥齿轮传动接触分析

以多体系统误差建模理论和齿轮啮合原理为基础,提出含有机床运动几何误差以及齿轮副安装误差的螺旋锥齿轮齿面接触分析(Error tooth contact analysis, ETCA)方法。以SGM法(大轮展成法加工,小轮变形法加工)加工的弧齿锥齿轮为例,通过ETCA分析,得到机床运动误差和安装误差对螺旋锥齿轮齿面加工质量影响的定量关系,对ETCA和TCA的结果进行对比分析,结果表明机床运动误差和安装误差对螺旋锥齿轮的齿面接触质量有较大的影响,为了通过齿面接触分析达到更准确的反调加工参数的目的,采用ETCA的分析结果指导加工参数反调更为合理。     

双导程ZN蜗杆修缘成形磨削研究

双导程ZN蜗杆(又称法向直廓蜗杆)修缘的精密加工需要研究一种成形磨削方法。传统的蜗杆修缘磨削方法是根据加工经验对砂轮进行手工修形,加工效率低且难以实现高精度的齿形修缘磨削。为此,以ZN蜗杆修缘齿形的成形磨削为目标,在蜗杆法平面引入齿形修缘分析,建立ZN蜗杆修缘齿形的数学模型,依据空间啮合原理计算出蜗杆磨削的成形砂轮截形,并利用数控砂轮修整装置修整砂轮。为验证蜗杆修缘的成形磨削效果,选用实际生产中的某一双导程ZN蜗杆,在自主研制的数控砂轮修整系统和工厂的蜗杆磨床上进行试验,经过对成形磨削砂轮计算、修整和蜗杆磨削,结果表明,磨削蜗杆的修缘量满足预期设计要求,蜗杆齿形精度达到6级。表明该方法可用于双导程ZN蜗杆修缘的高精度成形磨削。     

滚齿加工建模仿真及误差分析

应用包络法对齿轮加工进行仿真,通过包络曲线族获得齿轮齿廓曲线,并分析了加工过程中对齿形误差产生影响的因素.应用Pro/E软件对获得的曲线族进行修正.实现了齿轮三维模型的建立.