农用拖拉机2K-H式增扭器的设计

本文对由单排2K-H型行星齿轮传动机构进行了分析。计算传动方案的传动比,根据传动比和安装条件进行配齿计算和模数选择,对行星齿轮传动进行受力分析及强度计算,并计算传动效率,输出轴的设计计算。     

交流伺服系统在供丝机中的应用

本文以针辊控制方式的改进为例，介绍了卷烟供丝中所应用的交流伺服控制系统的基本结构、伺服电机的工作特性及其性能优点。采用交流伺服驱动代替传统的机械式的凸轮传动机构，实现针辊电机与主电机的同步驱动。利用闭环控制技术，减小机组的传动误差，增强控制精度与稳定性。     

用圆盘铣刀加工直齿圆锥齿轮的工艺

1直齿圆锥齿轮直齿圆锥齿轮通常传动比范围为1~8,最大传动功率小于370kW,最大圆周速度小于5m/s,传动效率97%~99.5%,其传动机构多用于机床、汽车、拖拉机及其他机械中轴线相交的传动。直齿圆锥齿轮采用收缩齿,即从齿的大端(齿轮的外端)沿分度锥母线到齿的小端(齿轮的内端),齿高逐渐降低。直齿圆锥齿轮齿线为直线,并相交于节锥顶,所以齿高通常都是由大端到小端逐渐收缩。该种齿轮根据齿顶间隙(顶隙)的     

基于微分进化算法的非对称弧齿锥齿轮约束多目标优化

根据齿轮啮合原理和现代摩擦学理论,建立了以弧齿锥齿轮传动齿面上瞬时接触线方向与相对滑动速度之间夹角的余切值最小、传动总体积最小和齿面诱导法曲率主值最小为目标函数的约束多目标优化设计数学模型。对当前的微分进化多目标优化算法进行了改进,给出了适用于工程领域的微分进化约束多目标优化算法。借助于改进的微分进化多目标优化算法,通过范例对弧齿锥齿轮传动进行两目标和三目标优化设计。分析了齿面上瞬时接触线方向与相对滑动速度之间的夹角及齿面诱导法曲率主值对齿面接触强度和胶合强度的影响。     

某电动机构齿轮副静态接触与动力学仿真

某电动机构在工作过程中发现齿轮传动中心距超差并发生齿轮副传动失效故障,需要分析中心距超差对齿轮传动失效的影响.传统赫兹理论的推导存在许多假设,存在一定局限性.为了获得更加准确的结果,对故障齿轮副进行了有限元静态接触分析和动力学仿真分析.通过有限元静态接触分析获得了某电动机构故障齿轮副啮合过程中的齿面接触力与等效应力情况,通过动力学仿真获得了不同中心距条件下齿轮副传动过程中的角速度、角加速度及接触力的动态过程.结果表明,中心距的超差使输出转速的波动明显增大,使角加速度的峰值增大并引起了高频振动,同时使最大齿面接触应力增大,进而导致了某电动机构齿轮副的失效.     

销轮齿条传动运动特性分析及最佳齿形选择

初步分析了销轮齿条传动机构的运动特性。探讨了几种齿形的啮合特点,认为齿条齿形的选择与销轮销齿的数量有很大关系,因此在设计销齿传动机构时,齿条齿形的选择应根据销轮的结构而定。     

复式滚动活齿传动(CORT传动)--RV传动理想的更新换代产品

活齿传动是陈仕贤教授发明的一种创新传动技术,经过十多年不断地研究和改进,该转动技术的理论和结构设计已经形成了一套完善的体系。历年来,数代活齿传动的不同结构设计曾先后获得数项中国专利以及美国和欧洲专利,并分别获得1985年日内瓦世界发明与新技术展览会奖．中国国家发明奖．以及中国专利十周年展览会优秀专利金奖。目前的第四代活齿传动一全滚动活齿传动(Oscillatory Roller Transmission——ORT传动)已经成功地应用到多种工业产品中。     

电动执行机构中圆柱齿轮传动精确度的分析

随着自动化仪表的发展、提高,现代化技术的推广、应用,对电动执行机构提出了更高的要求。由于传动精确度是直接影响目标的精确性、工作的可靠性等,对产品质量起着重要的影响,所以对此进行一定的探讨是富于实际意义的。电动执行机构的减速方式主要有圆柱齿轮、蜗轮蜗杆、少齿差行量传动、摆线针轮等,本文仅讨论渐开线圆柱齿轮的传动精确度及应用。传动精确度问题自苏联的勃鲁也维奇在《机构精确度》一书中提出、分析、计算后,发展很快,美国的M.Michalec在《精密齿轮传动     

基于NX的差动轮系三维建模与运动仿真分析

差动轮系应用广泛,可以用于速度合成和分解,或用于变速传动。在本文中,应用NX软件中齿轮工具箱,进行差动轮系传动机构中直齿圆柱齿轮精确三维建模、齿轮啮合和齿轮移动等过程,同时在运动仿真模块进行差动轮系运动仿真分析,为零件的工艺设计或零件有限元分析等后续工作奠定基础,从而减少重复劳动,提高工作效率。     

基于传动误差数据的齿轮误差检测方法与系统

齿轮传动误差影响齿轮传动精度和平稳性,传动误差与齿距和齿廓偏差等齿轮误差数据有直接关系.利用单面啮合测试和虚拟仪器原理,构建了传动误差检测系统,研究了传动误差与齿距与齿廓偏差数据的关系,找到一种将齿距与齿廓偏差计算出来的方法.经过试验分析,验证了本方法和系统的准确性.     

机器人减速器传动误差建模与优化

为提高工业机器人旋转矢量(RV)减速器的传动精度,合理分配各零件的加工和装配公差,本文提出一种基于等价模型的RV减速器传动误差建模与优化方法.该方法根据RV减速器的传动结构,构建17自由度的等价误差模型,利用传统经验参数进行求解,获得减速器仿真传动误差;同时,将仿真传动误差与实际测量传动误差进行对比,运用最小二乘法建立经验参数辨识模型;在此基础上通过粒子群算法优化辨识模型中的经验参数,将该参数运用到实际RV减速器生产中,结果显示:与传统经验参数建立的误差模型相比,本文提出的方法使得传动精度的仿真精度误差平均缩小9.99%,大幅度提高了等价误差模型的准确性.     

机器人RV减速器声发射信号传播机理分析及实验研究

关于RV减速器的声发射信号传播机理目前还缺乏定量的分析．本文旨在分析和研究声发射信号在减速器内部的传播机理,实现对减速器磨损等故障的准确监测与评估．首先从RV减速器的运动学机理出发,建立声发射信号在RV减速器内部的传播模型,接着利用小波变换分析方法得到不同频段的声发射信号时频分量特征,进而建立RV减速器声发射信号趋势演化模型．通过RV减速器的加速退化实验,得到了4种不同磨损状态下的声发射信号演化趋势,验证了本文提出的声发射信号传播模型的正确性．     

Inelastic uniform torsion of steel members

This paper develops a mitre model for the shear strain distribution in steel members under uniform torsion. The mitre model provides reasonable approximations for the shear stress distributions, except near re-entrant corners, and accurate predictions of the fully plastic uniform torque. The elastic torque-twist relationship is predicted with high accuracy, and the inelastic relationship with reasonable accuracy. The mitre model uses a simple approximation to the shear strain distribution caused by uniform torsion. It can be expected to provide a relatively simple method of predicting the inelastic behaviour of steel members when uniform torsion acts in combination with axial force and bending moment.     

Nonlinear analysis of steel frameworks through direct modification of member stiffness properties

This paper presents a computer-based method for nonlinear analysis of planar steel frameworks under monotonic loading that is directly based on the matrix displacement method of analysis. Stiffness degradation factors progressively deteriorate the post-elastic bending, shearing and axial stiffness properties of framework members over an incremental load history until failure of part or all of the structure occurs. The analytical procedure is based on Timoshenko beam theory to allow for the analysis of frameworks for which effects of shear deformation on elastic behavior may be significant, and employs transcendental stability functions to model the effect of axial force on the bending stiffness of members. Also accounted for is the influence of residual stresses on the initial-yield and full-yield capacities of members, and the effect of both combined moment plus axial force and combined moment plus shear force on the post-elastic behavior of members. The nonlinear analysis method is applied for two benchmark planar steel structures, and it is shown to give results comparable to both experimental and analytical results previously published in the literature. The method is readily implemented on a computer using conventional matrix structural analysis techniques, and is directly applicable for the efficient nonlinear analysis of frameworks of any scale or complexity.     

Stress distributions of short fiber composite materials

In the present study, the normal and interfacial shear stress distributions of short fiber composites under a force parallel to the fiber direction are investigated by using the global-local finite element method. A finite element analytical procedure will be developed by combining the hybrid stress finite element method and the conventional displacement-based plane stress element to predict the normal and interfacial shear stress of short fiber composites. The effects of different geometrical shapes of fiber end, the ratio of fiber length to diameter, the fiber volume fraction and the elastic modulus ratio to the normal stress and the interfacial shear stress distributions of short fiber composites will also be conducted. The geometrical shapes of fiber end under present investigation are blunt, V-shaped, wedge-shaped and semi-circular, respectively.     

新型力解耦机器人六维力传感器研究

用应力分析的方法得到了一个可用于测力的应用测量原理 ,根据该原理设计了一种新型六维力传感器 ,分析了其受力与变形元件测量点应力的对应关系。分析结果表明该传感器的输出是力解耦的 ,具有结构简单 ,工艺性好等优点 ,可应用在仿人行走机器人脚部以及其它类型机器人需要使用多维力传感器的场合     

填埋场典型复合衬垫系统单剪试验数值模拟

为研究填埋场典型复合衬垫系统接触面间的滑动特性,建立典型复合衬垫系统单剪试验的有限元模型,用ANSYS对其进行数值仿真分析.研究复合衬垫不同界面在不同法向力下的滑动特征;绘制衬垫系统不同界面节点的应力 位移关系曲线,得到不同法向力作用下各个界面不同位置点沿剪切位移方向和垂直剪切位移方向的切应力变化规律;分析接触面内节点的剪切位移随载荷步的变化特征.结果表明：随法向力的增加,滑动界面将发生转移;在低法向力（56 kPa）条件下,土工网 土工膜界面发生滑动;在高法向压力条件下（压力超过560 kPa）,土工膜 黏土界面发生滑动.     

Optimal design of steel frames subject to gravity and seismic codes' prescribed lateral forces

Allowable stress design of two-dimensional braced and unbraced steel frames based on AISC specifications subject to gravity and seismic lateral forces is formulated as a structural optimization problem. The nonlinear constrained minimization algorithm employed is the feasible directions method. The objective function is the weight of the structure, and behaviour constraints include combined bending and axial stress, shear stress, buckling, slenderness, and drift. Cross-sectional areas are used as design variables. The anylsis is performed using stiffness formulation of the finite element analysis method. Equivalent static force and response spectrum analysis methods of seismic codes are considered. Based on the suggested methodology, the computer program OPTEQ has been developed. Examples are presented to illustrate the capability of the optimal design approach in comparative study of various types of frames subjected to gravity loads and seismic forces according to a typical code.     

AC-RV新型驱动单元研制

以高性能交流伺服电机与高精度、高刚度的RV减速 器构成的驱动单元是新一代工业机器人比较流行的驱动方式．本文主要介绍了上海市科委的 新型驱动单元项目．包括研制背景,主要技术要求,RV减速器的传动原理、优越性,交流伺 服电机的主要技术指标,以及我们设计制作的基于ISA总线的交流伺服驱动卡的设计思想, 技术创新和实现．最后给出了鉴定结果和对下一步研究工作的展望．     

Development of a piezoelectric polymer film sensor for plantar normal and shear stress measurements

We have developed a new sensor prototype for plantar pressure measurements during gait. The mechanical stress at the plantar surface has two components, pressure acting normal to the surface and shear stress acting tangential to the surface. The shear stress can be further divided into anterior–posterior (AP) and medial–lateral (ML) components. The developed sensor simultaneously measures both normal and shear stresses. It utilizes commercial polyvinylidenefluoride (PVDF) material and consists of four separate sensor elements. This paper presents the sensor development and calibration for each force components. A shaker providing dynamic excitation force was used in the calibration. Average sensitivities computed from the results were (12.6 ± 0.8) mV/N for the normal force, (223.9 ± 20.3) mV/N for the AP shear force and (55.2 ± 11.9) mV/N for the ML shear force. A preliminary plantar pressure measurement was also done. The results obtained were promising. However, the sensor developed here is the first prototype. In future, a matrix sensor based on this principle is planned to be constructed.