曲轴连杆颈圆度误差的测量与评定方法研究

曲轴轴颈圆度是评价曲轴合格性和加工精度的一项重要指标。针对曲轴综合测量过程中连杆轴颈沿主轴颈公转运动,导致连杆轴颈的检测数据无法直接用于圆度误差评定的问题,建立基于运动坐标系的圆度误差检测模型,实现了连杆轴颈检测数据转换处理。同时,深入分析用于圆度误差评定的3种最小二乘法的适用条件,结合采样数据的特点实现了连杆轴颈圆度误差的高精度检测。以某型号发动机曲轴为例进行大样本误差检测试验,并与最小区域评定结果进行对比,偏差在1μm以内。数据分析表明了所提出的曲轴连杆轴颈圆度误差检测方法理论上的正确性及工程实践的可行性。     

数控曲轴铣床加工发动机曲轴实例

我厂在小松公司GPM900B-2型曲轴数控铣床上加工从德国引进B/F8L413F型风冷发动机的主轴轴颈、连杆轴颈和卵形轮廓曲臂外圆(附带加工曲臂端面),如图1所示。铣刀主轴转速36r/min,刀盘直径920mm,切削速度104m/min,最大进给速度2400mm/min;工件主轴转速0～5r/min。一根曲轴毛坯整个铣削(一次完成精加工)过程只需40min左右。到目前为止,在该机床上已加工出曲轴4000余根,与传统加工方法比较,经济效益相当显著(详见表1)。 图2是曲轴装夹和同时加工主轴轴颈及连杆轴颈示意。由图可以看出各个曲臂的分度情况(90°分度),曲轴绕回转中心转一周即可…     

曲轴的数控铣削粗加工

曲轴适合于数控铣削加工(当然轴颈还需磨削),装夹方式见图1。现以X轴为工件回转轴,Y轴为主轴铣刀盘进给轴,Z轴为连杆轴颈或曲臂外圆铣刀盘进给轴,编制主轴轴颈、连杆轴颈和曲臂外圆的加工程序。在编程中以X、Y、Z轴负向为进给方向,尺寸以G91方式编制,长度单位0.01mm,角度单位0.01°(机床专用子程序除外)。一、主轴轴颈程序主轴轴颈相对工件回转中心剖面为同心圆。可使用切入铣削加回转铣削法或阿基米德螺线(以下简称阿线)铣削加回转铣削法。在使用前法时,可先编程     

汽车发动机曲轴连杆轴颈圆度临床测量的研究

本文根据三点法和两点法误差分离理论，给出了汽车发动机曲轴连杆轴颈圆度测量的新方法，为在ＭＢ８２６０曲轴磨床上实现连杆轴颈圆度误差的临床测量，设计并制作了一套临床测量系统，在此基础上进行了一些初步的试验研究，试验结果表明，在车间条件下临床测量曲轴连杆轴颈的圆芳误差是行之有效的。     

曲轴的高效加工

曲轴粗加工广泛采用数控车床、数控内铣床、数控车拉床等对主轴颈、连杆轴颈进行数控车削、内铣削、车一拉削加工,以有效减少曲轴加工的变形量。曲轴精加工广泛采用NC控制的曲轴磨床对其轴颈进行精磨加工。玉柴机器股份有限公司对六缸柴油发动机曲轴主轴轴颈和连杆轴颈粗加工采用车一车拉工艺,精加工采用精磨工艺。由于使用的机床为多动力头,控制系统采用多通道数控,因此精度高、效率高。     

精密曲轴连杆颈磨削加工技术的研究

汽车发动机曲轴结构复杂,加工要求高,保证连杆轴颈的各项技术要求是曲轴加工的关键。分析了连杆轴颈的主要技术要求和工艺,巧妙设计了精磨连杆轴颈夹具,并基于Pro/E软件行为建模技术对精磨连杆轴颈夹具的静平衡配重进行了设计,实现了用普通曲轴磨床磨削精密汽车曲轴,为企业取得了良好的经济效益。     

圆度补偿在曲轴磨床上的应用

以曲轴磨削加工表面形状误差为研究对象,针对曲轴工件自身刚性极差,在装夹应力、磨削作用力因素影响下,对在加工过程中其弹性变形对连杆颈圆度误差而产生的圆度问题进行探讨,重点论述磨床圆度补偿功能对曲轴加工质量作用。     

基于误差转换的汽车曲轴圆度及圆柱度误差评价数学模型构建研究

针对国内汽车曲轴轴颈圆度误差、圆柱度误差检测普遍存在的效率低、精度低等问题,建立基于误差转换的平面曲线和空间曲线误差数学模型,结合圆和圆柱的数学表达建立满足最小包容条件的圆度和圆柱度误差评定数学模型,并采用遗传优化算法计算出符合最小评定要求的曲轴轴颈形位误差,解决了理想包容要素位姿参数不精确的问题。同时,建立基于图像域的汽车曲轴轴颈形状误差检测试验台,针对测量过程中连杆轴颈沿主轴颈公转运动,从而导致连杆轴颈图像域检测数据存在坐标不归一问题,以曲轴法兰端特征孔为基准,通过模板匹配特征与孔边缘提取实现了连杆轴颈圆度和圆柱度测量数据空间坐标归一化处理。以某型号发动机曲轴为例进行大样本误差检测试验,并与三坐标测量机测得的结果进行对比,数据分析表明提出的曲轴轴颈形状误差检测方法的精度为1μm,且重复检测误差在0.1μm以内,证明了其理论上的正确性及实践操作的可行性。     

异型配重铁曲轴连杆颈车削夹具的设计与应用

S-217曲轴连杆颈车床是车削曲轴连杆颈主要设备之一.对称型配重铁曲轴连杆颈的加工,其圆周方向的定位一般是铣削末端配重铁边缘形成一平面加以定位.对于非对称型配重铁曲轴连杆颈的加工,则无法采用这种方法.文章采取了一种全新的、完全脱离依赖末端配重铁办法,首先在末端弧顶处铣一平面加以定位加工曲轴第1、6连杆颈(6拐曲轴),然后再以第6连杆颈外圆定位加工第2、5和3、4连杆颈.经生产实践证明,该方法定位精度高,加工过程稳定,具有很好的应用推广前景.     

国内外曲轴磨床及磨削生产线

一、国内曲轴磨床及磨削生产线 1.采用普通外圆磨床(M131、M1350)加工曲轴主轴颈,采用曲轴磨床(MQ8240、MQ8260)加工曲轴连杆轴颈,加上曲轴运载装置组成曲轴磨削生产线。 (1) 磨削曲轴轴颈时,砂轮只作横向进给(切入法)。由于横向进给磨削时砂轮作用在曲轴上的横向压力很大,为了防止曲轴的弯曲,被加工的轴颈要支承在可以调节的机械开式中心架上,边磨边调整。若中心架的支承性能不好,曲轴在弯曲的情况下磨削,会破坏被磨轴颈的同轴度并产生圆度误差,情况严重的还会在磨削时产生自激振动,破坏磨削表面质量。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

基于多目标非支配解提取法的电力系统无功优化

针对传统的电力系统多目标粒子群优化算法采用权重系数法将多目标转化为单目标,从而忽视了各目标函数间的竞争关系这一问题,提出将非支配解提取法运用到电力系统多目标无功优化中,并设定了一套提取规则,以电力系统中的有功网损、电压偏差和电压稳定裕度为目标,使目标在充分竞争的情况下得出Pareto最优解,利用IEEE-14节点系统对多目标非支配解提取法的电力系统无功优化进行了仿真测试。研究结果表明,该算法一次运行可以得出多组非支配解,既有偏向单个目标的解也有兼顾所有目标的解,克服了权重系数法的盲目性和单一性,可使电力决策者根据实际问题选择最优解,具有较好的灵活性与多样性。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.