齿轮机床补偿运动误差的测试与诊断

本文基于齿轮机床为适应加工斜齿轮需要都具有补偿运动的功能,阐述了一种新的补偿运动误差的评定、诊断方法及系统。据相关准则,新方法将运动误差变换到轮齿的法向进行考察并计入几何误差,及力、热效应的影响。新系统不需像传统方法一样采用精密元件组成基准系统,而是采用经被测机床精切后的工件齿轮作测量元件,运用误差相关(工件误差与补偿运动误差相关)和误差分离的原理,求解补偿运动误差和工件齿面波度误差,并捕捉二者误差的主源。显然,这是对传统方法的一次撞击。文章论述了新系统的原理、特性及误差主源的诊断过程。最后还给出了实例。     

长光栅在机床螺旋运动误差补偿中的应用

本文介绍了以长光栅为精密机床的工作台运动在位检测元件、以TP-STD工业控制微机为系统监控组件、以步进电机——机械传动系统为执行机构的机床螺旋运动误差补偿系统。本系统采用离线检测在位补偿的方法实现系统误差的综合补偿,提出了工作台单位行程工件主轴转角量的概念、并将它分解为几个组成部分,以便实现螺旋运动的微观判别和实时补偿,该系统已用于Y7316X小砂轮成形磨齿机的螺旋运动机构中。     

干切滚齿机热变形误差模型及其误差补偿技术研究

针对YDE3120CNC干切滚齿机床,运用热传导形成温度梯度原理、金属材料热膨胀原理、材料力学中梁的伸长和弯曲变形理论基础,分析了该机床热变形误差,并提出了一种滚刀与工件主轴相对位移热变形误差数学模型。在此基础上研制了一套用于干切滚齿机热变形误差补偿系统,利用该系统从间接和直接的角度测量出滚刀与工件主轴相对位移,然后进行热变形误差补偿实验。通过该实验,验证了该机床热变形误差数学模型的正确性及可靠性,为干切滚齿机床在线热变形误差检测及补偿打下了基础。     

外圆补偿磨削的试验研究

基于误差分离技术和补偿技术的发展设计了外圆工件圆度临床测量和补偿系统。在Ｍ１３１外圆磨床上的补偿磨削试验结果表明，所设计的测量补偿系统能够达到改善被加工工件圆度的目的，补偿后工件圆度误差减少近３０％。     

光学镜面离子束加工系统设计和分析

研究了离子束加工系统的后置算法和误差补偿等问题。基于DH矩阵法,建立了系统的运动学方程,分析了工艺中离子源和工件的安装误差以及离子源相对于工件的六项对刀误差对加工定位的影响,建立了误差模型。在求解运动学方程时引入纠补矩阵,以消除离子源确定性的安装偏差对切平面定位误差的显著影响。补偿后的误差分析表明：切平面误差模型对对刀和安装精度提出要求后,靶距误差和入射角度误差同时也受到了限制,对加工的影响可以忽略不计。     

车削精度主动控制系统与动态模型的研究

本文分析了以压电陶瓷作为驱动元件的振动切削刀具的振动特性和实现刀具谐振切削的电路匹配,分析了主轴误差补偿方法的特点,提出以振动切削和误差补偿为基础的提高车削加工精度的主动控制系统,并建立了该系统的动态模型,推导其频率响应函数,实验证实了该方法能全面地提高工件的加工质量。     

多轴数控机床几何误差的软件补偿技术

论述了在“华中Ｉ型”数控系统中开发的数控机床几何误差的软件补偿技术。分析了各轴的误差元通过运动链传播的建摸问题和其对切削刀具在机床工作空间中的姿态误差的影响;建立了机床结构的每个误差元和切削刀具相对工件位置误差相联系的通用数学模型;采用激光干涉仪直接测量的方法来获取误差模型中各个误差元参数,提出了一种测量机床运动部件滚摆角的新方法;测量点的误差参数被存储在计算机内,在测量点之间采用线性插值来获得补偿点的误差参数。数控系统每８ｍｓ中断一次,读取与补偿点相关的位移和转动误差参数以及刀具的参数,利用误差模型计算刀具相对工件的误差在各个运动轴上的误差分量,该误差分量被数控系统叠加到各运动轴的指令位移上,使各个运动轴产生附加的运动,从而实现数控机床几何误差的软件补偿。对比试验表明该补偿技术能使数控机床的几何误差减小７０％。     

数控插齿机的误差建模与误差补偿解耦

为提高数控插齿加工精度,需对其误差进行补偿。通过分析插齿机床的运动特点,建立了插齿机运动模型;基于机床误差运动学原理,推导出用齐次变换矩阵描述的刀具相对于工件的误差模型;基于小误差补偿运动假设和微分变换原理,对各轴运动副的误差补偿量与刀具相对于工件的位置及方向误差模型间存在的耦合关系进行了解耦,获得了影响插齿加工精度的各运动副位置或方向误差补偿量。     

机械加工系统中热源故障的诊断

机床、刀具、工件和夹具所组成的加工系统存在着几何误差源、热源和力源,它们都以自己特有的规律反映给被切工件,形成工件的加工误差。热效应造成的加工误差占工件加工误差的40％～70％。我们在诊断实践中摸索出了加工系统热效应主源的诊断方法,现介绍如下。     

双转台五轴数控机床误差实时补偿

以双转台五轴数控机床为对象,建立各移动轴和旋转轴运动的数学模型,以工件坐标系为基础坐标系,应用齐次坐标系变换理论,推导任一时刻各轴运动在工件坐标系中的位置误差数学表达式.针对五轴机床的移动轴和旋转轴同时运动存在耦合的情况,提出一种分步实施的解耦补偿方法,即在实施误差补偿时首先进行姿态误差补偿,通过旋转轴的旋转运动将工件的实际姿态调整到与理想姿态相同,然后通过移动轴的平移运动进行位置误差补偿,并相应建立五轴机床误差补偿数学模型.通过仿真分析和对曲面零件的实时补偿加工试验,明显提高加工精度,并有效避免直接进行补偿加工过程中可能带来的运动干涉情况,从而验证该五轴机床误差补偿数学模型及其实时补偿的可行性和有效性.     

Pitch deviation measurement of an involute spur gear by a rotary profiling system

This paper presents surface-profiling based gear pitch deviation measurement for an involute spur gear. A rotary profiling system, which consists of an air-bearing spindle and a displacement sensor with a diamond stylus, is employed to measure gear pitch deviation. In measurement of gear pitch deviation, an eccentric error between a gear axis and a motion axis of the rotary stage in the profiling system would affect accuracy of gear profile measurement. In this paper, at first, the influence of the eccentric error on measurement of gear pitch deviation is estimated in computer simulation based on a geometric model of the profiling system. After that, a new scanning method named “opposite-direction dual scanning method” is proposed so that a steep profile of gear flank surface with a local slope of up to 90° can be measured by the developed rotary profiling system. For compensating distortions in the measured gear tooth profile, which are induced not only by the eccentric error but also by a probe offset introduced by the proposed scanning method, a self-calibration and compensation method is applied. To verify the feasibility of the proposed method, measurement of gear pitch deviation of a master involute spur gear with a certificate data is carried out. Measurement uncertainty of the proposed method is also analyzed.     

滚齿机热误差补偿技术研究

通过对滚齿机的热误差源进行综合分析及温度测点的优化布置,充分利用齿轮加工过程中测得的误差数据,采用最小二乘法建立了滚齿机的热误差数学模型,研制了滚齿机热误差补偿的硬件系统,利用该系统在Y3150K型滚齿机上进行了误差补偿实验,实验结果表明,实施热误差补偿后,齿轮加工精度提高2级以上,补偿效果明显。     

数控随动磨床加工凸轮方法及其精度补偿策略

针对凸轮随动磨削中因工件轴转速差、伺服系统响应偏差、硬件制造误差等重复性误差影响因素造成的零件制造精度下降问题,将在线测量技术和Sinumerik 840D数控系统的插补表与电子齿轮功能应用到机床运动控制系统中,开展了随动磨削工艺的运动轨迹和控制方案分析,提出了由内嵌在系统PCU上的VB程序来处理在线测量获得的360个离散误差补偿数值,自动生成带插补表与电子齿轮功能的专用加工程序,利用同轴运动叠加控制方法,把补偿值叠加到进给轴上,使带误差补偿数据的凸轮加工NC程序不断根据实际加工状态更新,最后在工程样机上进行了磨削试验。试验结果表明,发动机凸轮轴的廓型最大加工误差降到了2.6μm以下,残余误差主要来源为机械振动、非线性摩擦扰动等随机性偏差。该运动控制和误差补偿方法能在实际加工中较好地补偿重复性误差因素对工件精度产生的影响。     

考虑运动误差的数控插齿机插齿啮合分析

以多体系统理论为基础，根据数控插齿机运动的实际情况，在考虑了由于制造、安装、运动控制不精确以及其它原因引起的初始位置误差等因素后，对数控插齿机的插齿啮合进行了分析，推导出包含误差在内的工件齿面方程，为数控插齿机进行实时测量与补偿和进一步研究误差因素对齿轮加工的影响提供了一种较好的误差分析方法。     

A generating method for digital gear tooth surfaces

Based on the theories of digital conjugate surface and gear meshing, a generating method for digital gear tooth surfaces (DGTS) is demonstrated in this paper. The research focuses on the conjugate motion between the DGTS, represented by discrete points, and the cutter figuration determined by analytic function in the manufacture process. Conjugate points in the cutter section corresponding to the discrete points on the digital surface and conjugate movements are solved. Automated sequence arrangements of the generating movement parameters have been performed and the discrete generating movements are interpolated in a continuous conjugate motion along the order. Strategies of error analysis and error compensation are also discussed in this paper. Computer-simulated examples of the generating machining of involute DGTS and non-standard shaped DGTS, the parameters of machining motions and real tooth surfaces verify the developed method. The research develops a new idea for the machining of DGTS, which breaks the limitations of conventional approaches based on analytic surfaces. It is of important theoretical and practical value to manufacture digital surfaces. Our method is not only be applicable in generating machining of discrete DGTS and analytic gear tooth surfaces with complex geometric design, but also in contributing to the processing of discrete digital cam and other 3-D digital surfaces .     

Research on thermal deformation of large-scale computer numerical control gear hobbing machines

Research on thermal deformation of large-scale computer numerical control (CNC) hobbing machines is on the purpose of obtaining the law of thermal deformation of gear hobbing machines to improve machining precision. According to the structure characteristics of hobbing machines, this paper presents a novel computing model of thermal deformation based on the theory of the thermal expansion deformation of metallic materials, the extensional beam theory, non-uniform temperature distribution of the Euler-Bernoulli beam and Kirchhoff theory of plane-section assumption. Then, the coupling theory of axial and bending deformation of hobbing machines based on the deformation element and equilibrium element method is proposed. The experimental measurement system and platform for thermal deformation of gear hobbing machines is established. The temperature and displacement data of thermal deformation of a certain type gear hobbing machine is analyzed, which has demonstrated the law of thermal deformation of hobbing machines. The locus curves for overall displacement error of cutting points and teeth trace error are obtained. Comparing deformation theory and experimental data, the relative error is lower than 5%, which verifies the computing model proposed by this paper, and shows the research method has great significance for structural optimization, local temperature control, and prediction and compensation for thermal deformation error of gear hobbing machines.     

基于试切误差补偿的斜齿插削技术与实验

为了提高数控插齿机插削斜齿精度,提出了一种基于试切误差补偿的数控加工方法。首先,在分析斜齿螺旋线偏差产生机理的基础上,采用线段逼近理论主运动曲线,计算满足加工精度要求的线段最大许用步长和曲柄转角;然后,通过试切齿轮,测取螺旋线偏差并反求出主运动曲线偏差,获得更准确的新理论主运动曲线;最后,在生产用G代码中,重新用线段逼近新理论主运动曲线。实验结果表明：加工的斜齿轮螺旋线偏差达到7级精度,结果符合预期,验证了技术方案的可行性。     

渐开线齿轮加工过程中的大周期误差研究

基于齿轮误差理论,对渐开线齿轮大周期误差进行研究。大周期误差属于低频,主要包括滚齿加工中的几何偏心、运动偏心和它们的合成与补偿,以及在插齿加工中的插齿刀的偏心误差。研究表明,对于滚齿加工来说,几何偏心对左、右齿面产生的啮合线误差等于该齿面上的径向与切向之和;运动偏心对左右齿面产生了一个大小相等且方向相反的误差且误差曲线是正弦曲线;几何偏心而不是运动偏心对齿廓径向误差有影响;可以引入几何偏心去补偿运动偏心。     

Dynamic analysis of gear-rotor system with viscoelastic supports under residual shaft bow effect

This paper investigates the dynamic behaviors of a gear-rotor system with viscoelastic supports under effects of the gear eccentricity, the transmission error of gear mesh and the residual shaft bow. The investigated dynamic characteristics include system natural frequencies and steady-state response. The finite element method is used to model the system and Lagrangian approach is applied to derive the system equations of motion. The results show that the mass, the stiffness and the loss factor of the viscoelastic support will significantly affect system critical speeds and steady-state response. It needs larger loss factor and more rigid stiffness of the viscoelastic supports to suppress the systematic amplitude of resonance. As the results shown, the magnitude and phase angle of the residual bow have tremendous influence on first critical speed when the geared system mounted on stiff viscoelastic supports. The transmission error of the gear mesh is assumed to be sinusoidal with tooth passing frequency and it will induce multiple low resonant frequencies in the system response. It is observed that the excited critical speed equals to the original critical speed divided by gear tooth number.