基于有限元分析的微孔钻削测力仪研究

通过分析应变式测力仪传统理论模型,设计了一种用于微小孔钻削测力仪的灵敏元件等效模型.利用有限元分析工具对测力仪灵敏元件进行了动力学和静力学分析,对测力仪的结构尺寸进行了优化设计,使测力仪的固有频率和灵敏度达到较为理想的状态.在此基础上研制了一套高灵敏度应变式微小孔钻削测力系统,通过试验验证,取得了比较理想的微小孔钻削过程力信号曲线,测力仪的测力范围、灵敏度、固有频率都达到了设计要求,可以满足实际工程应用和测试研究的需要.     

应变片式微小孔钻削测力仪钻削力的实验研究

应变片式动态钻削测力仪是钻削及其孔加工机理研究仪及实现钻削加工过程自动监测必不可少的手段,该测力仪中用来测量轴向力及扭矩,提出了具有辅助支承的测力仪结构方案,研制了具有很小的鉴别力阈值,较高的灵敏度和较大承载能力的应变片工微小孔钻削测力仪。     

高灵敏度测力仪及传感器布置形式研究

文中提出一种新型传感器布置形式的测力仪结构,适用铣削、钻削等过程中动态切削力的测量.基于石英晶片不同切型的特点,提出了一种新的测量方式,设计了2种传感器布置形式.对测力仪原理进行分析,建立输入与输出之间的理论输出模型.分别对2种测力仪进行静态性能标定实验,结果表明:2种布置形式的测力仪的线性度和重复性误差均小于1％,并...     

微小孔振动钻削力的实验研究

介绍了高灵敏度的微小孔钻削测力仪的结构设计及微小孔钻削力测量系统的工作原理。通过多元正交多项式回归实验 ,得到了微小孔振动钻削力关于振动频率、振幅和进给量的非线性回归方程 ,进而分析了振动参数和切削参数对钻削力的影响 ,为深入研究微小孔振动钻削机理提供了必要的实验手段和有价值的研究方法     

《新型高灵敏度压电式钻削测力仪》

压电晶体双向动态钻削测力仪是钻削及其它孔加工机理研究以及实现钻削加工过程自动监控必不可少的手段,亦可在其它各个方向用来测量轴向力及扭力矩。本文对传感器及测力仪的结构设计、计算给以全面论述,为使测力仪获得高性能,结构上采用优化后的弹性薄壁螺纹筒夹进行予载。得到高刚性、高灵敏度,则是在这一领域中的一个创新。     

基于自适应控制的深小孔钻削工艺研究

深小孔钻削工艺因其加工的半封闭性存在排屑困难、冷却润滑不良、刀具刚性差、强度低等工艺问题。本文在加工系统中设置测力测扭传感器适时监控加工状态,基于自适应控制系统调整钻削进给量,通过改进钻头结构参数设计,合理控制钻削工艺方法及加工参数,显著改善了加工效果。钻削试验结果证明综合经济效益明显,对同类似工艺问题的解决具有一定借鉴作用。     

内排屑深孔钻的钻削轴向力及扭矩测定

在深孔加工中,由于钻削作用的影响,工件材料产生变形,钻头与切屑、工件之间的摩擦产生钻削力和扭矩,导致产生切削热和钻头磨损,影响钻头耐用度和加工质量。本文讨论ＢＴＡ深孔钻的钻削力及扭矩测定等问题。１ＢＴＡ深孔钻钻削测力仪的设计设计测力仪弹性元件如图１所示。其Ａ端与机床进给机构连接器相连接,Ｂ端与钻杆连接,中部Ｃ为弹性体。在Ｃ的外圆表面粘贴电阻应变片。由于钻削力的作用,弹性体产生变形,使电阻应变片的电阻值发生变化,经电桥转化为电压变化信号输出,并由电阻应变仪放大,由示波器记录、显示测量结果。图１　…     

深孔钻削加工刀具状态监测的研究

在分析研究刀具磨、破损监测技术的基础上，针对普通测力装置笨重、安装困难的缺点，根据深加工系统的特点，提出了一种新研制的用于深孔加工刀具监测系统的应变式传感器。经实验证明，该传感器较好的解决了深孔钻削加工刀具状态监测的问题。     

整体式压电三向车削测力仪的研制北大核心CSCD

针对三维动态车削力的测量需求及刀杆式、平台式压电测力仪的不足,研制了一种带有双弹性环结构的整体式压电三向车削测力仪。设计了测力仪的2种结构方案,并对比了2种方案的优劣,阐述了测力仪和压电测试系统的测量原理,对测力仪进行了静态标定实验和动态冲击实验,实验结果表明:测力仪具有优良的静、动态性能,满足了动态车削力的测量需求。     

小直径深孔钻削监测系统

在对深孔钻削系统进行力学分析的基础上,针对小直径深孔钻钻头及钻杆直径小的特点,设计出一款用于小直径深孔加工监测系统的应变式传感器。     

Research on the piezoelectric torsional effect of a rectangular quartz disc and a novel drilling dynamometer

The theoretical foundation of a new-type drilling dynamometer (i.e. the torsional effect of a rectangular piezoelectric quartz disc), the structure design and calibration of the drilling dynamometer are investigated in this paper. By using the theory of anisotropic elasticity and the Maxwell electromagnetism, the torsion stress and the distribution of surface charge densities of a rectangular quartz disc are calculated. According to the theoretical analyses of the bound charge densities, the detection electrodes are effectively disposed on the surface of the piezoelectric disc. The experimental results show that the torsional effect exists in the rectangular quartz disc and the bound charges are linear with the torque applied. Based on the torsional effect, a new type of drilling dynamometer is designed, in which only four quartz discs are used. The axial force measuring cell consists of two X0°-Cut quartz discs, and by the partitioned electrode method only two Y0°-Cut quartz discs can simultaneously sense the radial force and torque. After static calibrations, the torque sensor has full reached the dynamometer standard stipulated by CIRP-STCC. Undoubtedly the drilling dynamometer will provide a new method for measuring the drilling force and monitoring the drilling process.     

新型压电式测力仪多功能静态标定平台的研制

为了解决压电测力仪的静态标定,文中介绍了自行研制的高精度、高刚性静态标定平台原理与结构。该标定台垂直力、水平力均采用螺旋加载方式,力值大小由三级标准测力环直接读取;而扭矩的加载采用"力×力臂"法,通过平移两个水平加载机构形成力臂,同时产生大小相等、方向相反的两个力来实现。对该标定台进行精度和刚度实测,结果表明相关指标均达到了CIRP-STCC标准。无疑,利用该标定平台可完成单向、双向力传感器、三向压电式测力仪以及钻削测力仪的静态灵敏度、线性、重复性、滞后以及横向干扰标定。     

深小孔镗削在线补偿方法的研究

采用压电陶瓷传感器等测量控制技术,在线补偿镗削加工中的误差,以提高镗孔精度。为实现深小孔镗削时的在线补偿,将镗杆做成双杆结构,使镗杆外径相对较小而长度较长,以满足精密加工深小孔的要求。     

Development of an innovative plate dynamometer for advanced milling and drilling applications

Tool geometry optimization, workpiece material characterization, process monitoring and optimization are based on the measurement of cutting forces by using machining dynamometers. Commercial dynamometers cover a wide range of machining applications, nevertheless there is a lack of measuring devices suitable for investigating milling and drilling applications with relatively small cutters and high spindle speeds. In this work, the development and testing of an innovative plate dynamometer designed for this purpose is discussed. The new measuring system was based on three high-sensitive triaxial piezoelectric force sensors arranged in a novel triangular configuration. Component design was optimized by using FE numerical approaches, according to the general guidelines derived from mathematical modeling of sensor dynamics. The prototype of the proposed device was manufactured and experimentally tested against two high-end commercial plate dynamometers by performing static calibration, modal analysis and cutting tests. Experimental results proved the excellent characteristics of the new device and its effectiveness for investigating advanced machining applications.     

新型六筋式应变切削测力仪研究报告

本文分析了传统应变测力仪无法有效提高静刚度的原因,给出了以剪切与拉压应变相结合方式为特点的六筋式应变切削测力仪设计方案及结构原理。标定实验证明,新型通用测力仪在静刚度和固有频率上可以远远超过压电式测力仪,刀杆式车削测力仪灵敏度达到测量克服切削力的水平。     

任意阶无漂移全极点有源低通滤波器的原理与实现

本文提出了一种有源低通滤波器的无漂移基本节电路，并将它推广到任意阶无漂移全极点有源低通滤波器的实现，给出了一般的电路结构，系统的设计方法和工程实验结果。这种滤波器具有良好的低漂移，低元件灵敏度特性，具有实际的工程应用价值。     

Design, calibration and error analysis of a piezoelectric thrust dynamometer for small thrust liquid pulsed rocket engines

Small thrust liquid pulsed rocket engines operating in pulsed mode have gained a good reputation in attitude control applications for their potential reliability and efficiency. However, the pulsed characteristic creates a difficult measurement problem. In this paper, a novel thrust dynamometer with high natural frequency is developed for accurately measuring the pulsed thrust. It consists of two shear mode piezoelectric quartz crystal sensors and an integral shell. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. Stiffness equations of the shell which are used to estimate the amount of interference are derived. The thrust dynamometer is calibrated both statically and dynamically. Static calibration uncertainty is evaluated. A trapezoidal impulse force is used to simulate the pulsed thrust for further characterizing the dynamic measurement performance of the thrust dynamometer. An evaluation algorithm of dynamic error is presented and used to evaluate the results of the dynamic simulation. The results show the thrust dynamometer has high sensitivity and natural frequency, good linearity and repeatability, and excellent dynamic performance. It can accurately trace trapezoidal thrust signal of 50 Hz without waveform distortion.     

Development and evaluation of tool dynamometer for measuring high frequency cutting forces in micro milling

A tool dynamometer is developed for measuring the high frequency cutting forces, and evaluated in micro milling of aluminum 6061-T6 using a tungsten carbide (WC) micro end mill. To improve the accuracy and productivity of the machining process, it is essential to monitor and control the machining process by measuring cutting forces. In order to improve the precision and quality of machined parts, high-speed machining with smaller micro tools is required, causing higher frequency cutting forces. The first natural frequency of tool dynamometers is high enough to precisely measure the high cutting forces. We investigate dynamic characteristics of the tool dynamometer theoretically and experimentally. The measurable frequency range of the developed tool dynamometer was higher than the commercial tool dynamometer, and the measured cutting force signals were not distorted at high-speed of above 60,000 rpm. The results showed that the developed dynamometer is able to measure the static and dynamic force components in high-speed micro milling.