A novel reverse measurement and manufacturing of conjugate cams in a diesel engine

This study presents a novel reverse measurement, CAD/CAM, and practical machining of conjugate cams on a computer-numerical-controlled (CNC) machine. This paper consists of five main components: a novel reverse measurement, displacement curve equations, CAD/CAM, practical machining and tests of the conjugate cams in a diesel engine. The diesel engine can output the 13-horse power and the rotational speed of 3500 rpm at the maximum. The results reveal that the torque and power are in good agreement between the reverse and the original conjugate cams in a diesel engine.     

偏心旋转式共轭凸轮递纸机构设计

由从动件的运动规律推导出控制凸轮的轮廓曲线是凸轮机构设计的关键技术,其核心是将从动件的运动与凸轮的运动联系起来.根据该偏心旋转式共轭凸轮递纸机构的具体情况,选择递纸摆臂作为从动件,设计其运动规律,从而计算出凸轮的轮廓曲线.ADAMS软件仿真结果表明:该偏心旋转式共轭凸轮递纸机构中递纸牙的工作路线和返回路线不重含,构成了一个雨滴状的封闭曲线,其运动轨迹满足了印刷机械对递纸牙运动轨迹的要求.     

共轭凸轮打纬机构运动精度分析

为了解决国产织机可靠性、稳定性较差,织机速度、运动精度有待进一步提高等问题,借鉴摆动凸轮机构误差分析方法,将凸轮机构反转原理、有效长度理论、转换机构法等多种误差分析技术应用到织机运动精度分析中。开展了剑杆织机共轭凸轮打纬机构在考虑基本尺寸误差、运动副间隙误差及凸轮副磨损误差3种情况下的打纬摇轴摆角误差计算方法的研究,建立了各摆角误差与凸轮转角之间的关系,运用Maple数值分析计算软件对打纬机构的运动精度进行了数学建模及分析计算。研究结果表明,在所考虑的3种主要误差中,共轭凸轮打纬机构的运动精度受凸轮副磨损误差的影响最大,应采取措施控制凸轮副磨损误差。并且该研究对无梭织机的改造和高速剑杆织机的设计应用具有理论指导作用和实用价值。     

基于Pro/E和Adams的共轭凸轮设计与仿真

用解析法对共轭凸轮曲线进行方程的推导,以摆动滚子从动件共轭凸轮为例结合Pro/Engineer开发实行三维参数化设计,再将设计后的组件导入Adams进行模拟仿真。这样不但使解析法设计变得大为简洁,而且使后续的分析也变得更为可观,从而提高了设计效率和质量,缩短了开发周期。     

Flow rate measurement in flows with asymmetric velocity profiles by means of distributed thermal anemometry

Flow rate in closed conduits is one of the most frequently measured parameters in industrial processes and in gas and water supply. For an accurate measurement, flow meters typically require a fully developed symmetric flow profile with preferably no radial or tangential velocity components. This is commonly secured by mounting flow meters in a pipe at a sufficiently long distance downstream any change in cross-section or pipe direction. In this paper, we introduce a new approach for flow rate measurement of gases or liquids that employs a novel spatially resolving fluid velocity sensor basing on thermal anemometry. The new principle allows accurate flow rate measurements for non-axisymmetric velocity profiles, even directly after pipe bends, T-junctions or other alterations in the pipe geometry. This is exemplified for air flow in three different pipe bend configurations.     

On the influence of measurement errors in the kinematic analysis of cams

This work deals with the influence of construction and measurement errors on the accelaration law of planar cams. For this purpose a computer program is described which, using as an input the polar coordinates of the real profile, gives as output the lift and accelaration laws. These calculated values may be compared with the theoretical ones. The influence of measurement errors is investigated and a formula that allows a choice of the optimum computational step is derived.     

Calculating the reliability of machine parts by means of truncated probability-distribution functions

A new approach to calculating the reliability of machine parts is proposed, on the basis of truncated probability-distribution functions.     

Shaping of parts with a helical surface by means of a disk mill

Russian Engineering Research -     

一种新的计算摆杆共轭凸轮最小基圆半径的方法

对摆动从动件共轭凸轮的等值基圆半径轴心许用区边界的性质,进行了深入的分析,简化了其中一条边界的曲线的计算,给出了一种新的简便的计算等值最小基圆半径的方法,使该问题由原来的求解三元非线性方程组,简化为求解二元非线性方程组。     

Roughness form and waviness measurement by means of light-scattering

This paper deals with a non-contact, optical measuring method which unites the assessment of roughness form and waviness in one single instrument. The     

利用MAX6675组建测温网络

分析了集成温度传感器的应用局限性以及常用热电偶和热电阻测温系统的缺陷,提出了用高度集成的热电偶信号处理芯片MAX6675组建测温网络（系统）的优越性。介绍了MAX6675的工作原理及特点,并给出了基于MSP430单片机测温网络的硬件实现和软件设计。     

Monitoring of diamond disk wear in stone cutting by means of force or acceleration sensors

The application of sensor systems is becoming more commonplace in improving productivity, automation, and reliability. The sensors employed in such systems possess signal and information ability for enhancing the monitoring and control of machining processes. Although measuring force and acceleration signals have been commonly used for the monitoring of metal machining processes, their application to stone cutting has not been well developed, which is perhaps due to the complexity of the interaction between the stone and the diamond disk. In order to enhance knowledge in this area of applications, a multi-sensor system was developed and installed for the monitoring of stone cutting by diamond mill. The signals acquired and analysed by the system include force and acceleration under different machining conditions. The measured signal data was used to perform time-domain analysis. The results indicate the feasibility of using the RMS features of force or acceleration signals along z-axis for the monitoring of disk wear.     

长光栅旋转测角法的研究

本文介绍了一种长光栅副相对旋转测角的新技术。建立在付立叶光学理论基础上的分析与实验结果是一致的。采用本方法与现代微机技术相结合,可以用非常简单的结构实现对小角度的高精度测量。仪器测量范围为±30′,测量精度为±0.5″。     

Error analysis on measurement temperature by means dual-color thermography technique

Dual color thermography is a non-contact measurement temperature technique used mainly when the emissivity of surface is unknown; it is based on ratio of monochromatic emissive power calculated by means Planck’s radiation equation and allows measuring the temperature of gray body surface objects without being assigned their emissivity and without approximations.For real surfaces, the emissivity varies with the temperature of surface as well as the wavelength and the direction of radiation. In this case, the dual color thermometry is executed by equipping the IR camera of two narrow band pass filters, so as to consider the surface emissivity of a quite constant value. This allows calculating the ratio between the radiative fluxes of the two different emission wavelengths that is almost independent to the surface emissivity.One of the crucial factor in this technique is the choice of the two narrow filter wavelengths. In fact the measurement errors depends directly on the two wavelengths and the variation of spectral emissivity related to the wavelength chosen and it also depends inversely on distance between central value of filters.In this paper, the authors have developed and validated a mathematical model of experimental setup to measure object surface temperature by means IR thermo-camera. This mathematical model was used to quantify the temperature measurement error in the dual-color technique. A novel correlation to estimate temperature measurement error was provided.     

Optimal disk clamp design to minimize stress variation of disks in a hard disk drive

To avoid disk waviness and warpage in a hard disk drive, it is desirable for the stress distribution on disks fastened to a spindle motor by a clamp to be uniform in the circumferential direction while sufficient clamping force is maintained. The objective of this work is to find a clamp configuration that minimizes the circumferential stress variation on the disks while maximizing the clamping force. Topology and shape optimization methods were employed to find the optimal clamp configuration. To facilitate the optimization problem, a model for the surface contact between the clamp and the top disk was simplified to a static model where the disk clamp and spring were connected. By incorporating the surface recess, the optimized clamp has equal stiffness in the circumferential direction, except for the four tooling hole areas. Numerical simulation confirmed that the optimized clamp reduced the stress variation by about 78% without sacrificing the clamping force; in fact, it increased the clamping force.     

Methodology for spectral emissivity measurement by means of single color pyrometer

The application of non-intrusive optical devices, such as infrared pyrometers able to measure the temperature of surfaces, makes possible the evaluation of emissivity curve of the tested materials at different temperature values. In this paper the authors propose a methodology for the spectral emissivity measurement by means of a single color pyrometer providing a semi-empirical formula, obtained experimentally at CIRA’s laboratory. The semi-empirical formula allows to know the actual emissivity value of the sample’s surface for whatever emissivity value set up on the pyrometer. The agreement between the experimental emissivity and the emissivity predicted by semi-empirical formula was verified.