大型齿轮齿距误差在机测量系统的研究

本文介绍了一种微机控制的大型齿轮齿距误差在机测量系统,论述了它的测量原理,系统组成与测量方法,并给出了具体的测量实例,实现了大齿轮齿距误差的在机测量。     

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。     

CNC 大型内齿轮在机测量系统研究

针对大型齿轮的特点和在机测量的难点,研究开发了大型内齿轮在机测量的相关技术,建立了可测量大型内齿轮齿形、齿向及齿距误差的ＣＮＣ大型内齿轮在机测量系统。     

大型齿轮齿距偏差在机测量仪的研制

大型齿轮特别是特大齿轮的快速精确测量一直是齿轮测量领域的技术难点。以相对法齿距测量原理为基础,运用圆周封闭原则,采用异步驱动同步测量的方式,研制出大型齿轮齿距偏差在机测量仪。测量仪通过对齿距偏差的逐齿测量,可以得出大齿轮的单个齿距偏差以及齿距累积总偏差,使用特殊的测头结构以及高精度的电感测微仪,可以满足大型齿轮旋转过程中测距偏差测量条件的要求。同时通过对测量系统的标定,可以拟合出测头偏转与电感测微仪示值的对应关系曲线。通过对测量结果进行重复性评估,表明该齿距测量装置的重复定位精度以及系统响应速度能够满足5 m直径大齿轮齿距偏差在机测量的要求。     

一种高效的齿轮齿面偏差在机测量方法研究

提出了一种在保证测量精度的前提下,提高齿轮齿面偏差在机测量效率的方法。首先根据渐开线齿廓,建立了齿轮齿面的测量模型;然后依据该模型,优化了齿面偏差在机测量过程中的测量点;最终实现齿轮齿面偏差的快速测量。重点研究了测量区域的确定、基于法曲率半径的测量点数量规划以及Hammersley序列的测量点分布规划。通过搭建的齿轮在机测量试验台,对此方法的有效性进行了在机测量实验,并与齿轮测量仪的测量结果对比,实验证明:该方法在保证测量精度的同时可使选取的测量点更加合理、数据处理容易实现且测量效率得到提升。     

齿轮在机测量中齿距误差分析

针对齿轮在机测量,指出了测量误差产生的原因是由于齿轮在加工过程中存在安装偏心误差和传动链误差.分析了齿轮在偏心情况下齿距的测量关系,提出了齿距测量补偿模型.得出结论:齿轮在机测量中由于偏心的存在,势必影响到测量结果的正确性,因此在机测量过程中对偏心量要实时修正以保证齿轮的精度.     

数控齿轮加工机床的在机测量系统

基于齿轮渐开线轮廓面的构型机理和数控齿轮加工机床的运动功能,提出了一种齿轮在机测量方法,并开发了相应的在机测量系统。该方法在不增加额外的测量系统机械机构的情况下,充分利用数控机床自身的高速、高精密和高可靠性的伺服运动实现渐开线齿轮的齿形、齿向及齿距等误差项目的在机测量。在机测量实验表明了该系统的有效性和可行性,是齿轮在机测量中高效率、高精度、低成本的解决方案,构成了数控机床质量保证系统中的一个重要环节。     

CNC比例驱动跟踪技术在大齿轮齿向误差测量中的应用

针对大齿轮的特点和在机测量的难点，研究开发了ＣＮＣ比例驱动跟踪技术。此技术具有跟踪精度高，跟踪性能好等特点，满足了高精度测量齿向误差的要求。     

单点线啮合齿轮齿厚测量尺寸研究

渐开线齿轮的齿厚测量尺寸通过测量公法线长度控制。但单点线啮合齿轮中大齿轮为一个大负变位的齿轮,渐开线部分较短,公法线无法测量。当单点线啮合齿轮中大齿轮模数较大时,测量法线长度有困难。提出了两种大齿轮齿厚测量方法：测量法线长度或测量J点（渐开线齿廓曲线与过渡曲线之间的交点）法向齿厚与齿高,分别用于中小模数和大模数单点线啮合齿轮齿厚的控制。推导了测量尺寸计算公式,并通过实例进行了验证。     

渐开线人字齿轮的跨距测量法

渐开线齿轮的滚齿加工测量，是关系到渐开线齿轮传动及承载能力的重要环节，对于齿面窄、螺旋角大，测量不到公法线的渐开线齿轮，本文提出了适合一般工厂实际操作的圆球测量跨距法，简易实用，效果很好。     

可编程动态倍频器在大齿轮在机测量中的应用

为解决大齿轮在机测量过程中采用比例驱动跟踪测量技术时转角脉冲当量过大的问题，研究开发了可编程动态倍频器。该倍频器的倍频范围为１～９９９，倍频值可直接由软件选择；该倍频器在输入脉冲宽度变化时能很好地动态跟随，倍频数绝对准确，倍频后的脉冲宽度均匀，完全满足了大齿轮在机测量的要求。     

In situ non-contact measurements of surface roughness

Surface roughness measurements are often required to validate a machining process. However, when using a 3D surface roughness measuring instruments it is usually necessary to remove the part from the machine tool between two operations, potentially introducing systematic errors. Furthermore, surface roughness measuring instruments are not suited for measuring heavy and large parts such as stamping dies. This paper presents a method to measure the surface topography of a part in situ, i.e. directly on the machine tool without removing the part. After introducing the sensor technology and the data acquisition chain, the effects of geometric imperfections of the machine tool and compensation for thermal effects on the measurement results are discussed. An application of the method is then presented to assess a finishing process on a five-axis machining centre including milling and polishing operations.     

Measurement of large internal diameters with a compact apparatus based on dual-wavelength heterodyne interferometer

This paper presents a new method for measuring large internal diameters of 3∼20 m with submillimeter resolution. The method is based on a novel dual-wavelength heterodyne interferometer for absolute distance measurement and a new positioning method for aligning the laser beams with the diameter of the bore to be measured. The compact apparatus and convenience of operation in situ are the distinguishing features of this method. Preliminary experimental results of the prototype of the apparatus proved the feasibility of this method.     

In situ calibration of rotating sensor coils for magnet testing

An in situ procedure for calibrating equivalent magnetic area and rotation radius of rotating coils is proposed for testing accelerator magnets shorter than the measuring coil. The procedure exploits measurements of magnetic field and mechanical displacement inside a reference quadrupole magnet. In a quadrupole field, an offset between the magnet and coil rotation axes gives rise to a dipole component in the field series expansion. The measurements of the focusing strength, the displacement, and the resulting dipole term allow the equivalent area and radius of the coil to be determined analytically. The procedure improves the accuracy of coils with large geometrical irregularities in the winding. This is essential for short magnets where the coil dimensions constrain the measurement accuracy. Experimental results on different coils measuring small-aperture permanent magnets are shown.     

大型轴类零件同轴度误差数据采集与数据处理系统的研究

运用半径增量法，建立了大型轴类零件同轴度误差的最小二乘法和最小条件法两种评定方法的实用数学模型。介绍了采用微机控制的大型轴类零件同轴度误差数据采集与数据处理系统的组成。在ＳＴＤ工业控制机的控制下，系统可自动实现测头调零、数据采集、数据处理、测量结果显示和（或）打印。运用该系统对工件进行了实际测量。实测结果表明：该系统安装调试方便，抗干扰能力强，测量速度和测量精度均较高。在车间条件下，既适用于加工中的大型轴类零件同轴度误差的在机测量，也适用于处于正常使用安装位置的大型轴类零件的在位测量。     

In situ measurement of alternating current magnetic susceptibility of Pd-hydrogen system for determination of hydrogen concentration in bulk

An alternating current magnetic susceptometer for use as a hydrogen gauge for hydrogen-storage materials was designed and developed. The experimental system can simultaneously measure the hydrogen equilibrium pressure and the magnetic susceptibility of metal hydrides. The background voltage of the susceptometer was stabilized for a long period of time, without any adjustments, by attaching an efficient compensation circuit. The performance of the susceptometer at a static hydrogen concentration was demonstrated by measuring the magnetic susceptibility of a Pd-hydrogen system under equilibrium conditions. The in situ measurement of the magnetic susceptibility of Pd during hydrogen absorption was carried out using the susceptometer. Since the in situ magnetic susceptibility obtained at a lower initial hydrogen pressure agreed with the magnetic susceptibility measured at a static hydrogen concentration, the susceptometer could be used to determine the hydrogen concentration in Pd in situ. At a higher initial hydrogen pressure, enhancement of the magnetic susceptibility was observed at the beginning of hydrogen absorption because the magnetic moments induced by the large temporary strain generated in the Pd affected the magnetic susceptibility.     

Application of the acoustoelasticity phenomenon in studying stress states in technological pipelines

The capabilities of the nondestructive ultrasonic method for evaluating stresses are demonstrated by an example of measuring non-design axial stresses in technological pipelines. The results of applying the acoustoelasticity effect, which was implemented in an IN-5101A device, obtained in direct in situ measurements of mechanical stresses in piping structures of the main equipment of compressor stations are presented. The features of applying the acoustoelasticity method for measuring stresses in these objects and its prospects for solving the problem of periodic testing of a stressed state of pipeline systems are considered.     

Nanometer profile measurement of large aspheric optical surface by scanning deflectometry with rotatable devices: Uncertainty propagation analysis and experiments

High-accuracy mirrors and lenses with large dimensions are widely used in huge telescopes and other industrial fields. Interferometers are widely used to measure near flat surfaces and spherical optical surfaces because of their high accuracy and high efficiency. Scanning deflectometry is also used for measuring optical near flat surfaces with sub-nanometer uncertainty. However, for measuring an aspheric surface with a large departure from a perfect spherical surface, both of these methods are difficult to use. The key problem for scanning deflectometry is that high-accuracy autocollimators usually have a limited measuring range less than 1000″, so it cannot be used for measuring surfaces having a large slope. We have proposed a new method for measuring large aspheric surfaces with large slopes based on a scanning deflectometry method in which rotatable devices are used to enlarge the measuring range of the autocollimator. We also proposed a method to connect the angle data which is cut by the rotation of the rotatable devices. An analysis of uncertainty propagation in our proposed method was done. The result showed that when measuring a large aspheric surface with a diameter over 300 mm and a slope of 10 arc-deg, the uncertainty was less than 10 nm. For the verification of our proposed method, experimental devices were set up. A spherical optical mirror with a diameter of 35 mm and curvature radius of 5000 mm was measured. The measuring range of the autocollimator was successfully enlarged by our proposed method. Experimental results showed that the average standard deviation of 10 times measurement was about 20 nm.     

Optimization of continuous wave nuclear magnetic resonance to determine in situ volume fractions and individual flow rates in two component mixtures

In this paper, the optimization of continuous wave nuclear magnetic resonance in two component flowing mixtures to determine the in situ volume fractions and the individual component flow rates is described from both an analytical and an experimental point of view. A simple and accurate measuring system is discussed and the analytical and experimental results are compared for oil-water mixes. The use of a relatively long polarizing magnet prior to the highly homogeneous detector magnet has been shown to improve the flow-rate range considerably and makes feasible a relatively inexpensive, accurate, and genuine two-phase or two component flow meter. By measuring the optimum value of H(1), or the rf level required to produce that optimum value, and by simultaneously measuring the magnitude of the signal at that time, both the in situ volume fraction and the flow rate can be determined. This is provided that there is no chemical reaction between the two components and that they travel at the same average velocity. The system may be also used for monitoring changes in constituency of a single substance since the optimum value of H(1) depends upon this constituency.