超声珩磨声学系统关键技术研究

超声珩磨具有珩磨力小、油石不易堵塞等普通珩磨所没有的优点。本文研究了超声珩磨工作原理以及声学系统的实现方法。提出了珩磨杆、珩磨头体均不振动的设计思想，分析计算了中心有圆柱孔的压电换能器和变幅杆，以及弯曲振动圆盘等关键部分。     

蠕墨铸铁发动机缸体噪声辐射测试分析

为准确分析蠕墨铸铁发动机缸体噪声辐射特性,基于LMS Test.Lab软件,使用力锤冲击激励法分别对灰铸铁和蠕墨铸铁铸成的发动机缸体进行振动噪声测试,基于理论推导出的力能量和声能量计算公式,使用激励力加权系数法进行加权分析。分析结果表明,被测的蠕墨铸铁发动机缸体力-声能量转换效率比灰铸铁发动机缸体力-声能量转换效率低35.43%,降噪性能优于灰铸铁发动机缸体。此研究表明力-声能量转换效率分析方法可以很好地分析不同材料发动机缸体的噪声辐射性能,为改善发动机缸体的噪声辐射性能提供理论基础。     

自动测量技术在珩磨中的应用

自动测 珩磨是一种精加工方法,它能经济地加工出尺寸和形状精度高、表面质量又好的孔。珩磨在汽车制造业中用得很广泛,有好几种发动机主要零件,如缸体中的缸孔(包括缸套内孔)和连杆大、小头孔的最后一道工序都是珩磨。珩磨自动测量是实现加工过程自动化的一个重要环节,对提高生产率、减轻劳动强度、降低废品率有十分显著的作用,其中,主动测量是用于珩磨加工中的自动测量技     

浅析MC11系列发动机缸体激光涨断技术的应用

中国重汽集团MC11系列发动机是中国重汽集团与德国MAN公司合作生产的目前世界上最先进的重卡发动机，该系列发动机缸体生产线上采用的是德国ALFING公司生产目前世界上最先进的激光涨断设备，缸体的材料为蠕墨铸铁GJV450，采用激光涨断工艺替代传统的铣、磨等分体加工方法，使曲轴孔主轴承盖定位精度、装配质量大幅提高，对提高主轴承盖承载、抗剪切能力及发动机整机性能具有重要作用。     

基于主轴电机功率珩磨加工过程的监控

珩磨加工是一种封闭式加工,珩磨油石是否按照所设定的加工工艺进行切削,将会影响到工件的珩磨加工尺寸精度和几何形状精度.由于在珩磨加工过程中其封闭式的加工环境,很难通过安装传感器直接获取加工信号,然而,可以通过获取主轴功率信号来监控珩磨加工过程.文中讨论了珩磨进给量与主轴电机功率的关系,从理论上分析了基于主轴电机功率的珩磨加工过程监控原理,给出了珩磨加工过程监控系统,最后进行了试验论证.     

铝合金汽车发动机缸体内壁表面改性的研究进展

节能减排是汽车制造行业面临的巨大挑战,发动机的轻量化结构设计及性能提升是解决该问题的重要途径之一。铝合金发动机缸体满足轻质要求,但其耐磨损性能较差,容易造成缸体内表面磨损失效,采用表面改性技术对铝合金发动机缸体内壁进行强化是有效的解决途径。相比于传统的铸铁内嵌式缸套,通过微弧氧化、等离子喷涂、电弧喷涂、超音速火焰喷涂等技术在铝合金基体上制备涂层可以极大地改善其耐磨性能,同时降低发动机的整体质量。本文详细阐述了适用于铝合金发动机缸体内表面改性技术的原理、特点及涂层制备等的研究进展,重点探讨了涂层的沉积成形机理及耐磨损机制研究现状,对涂层材料的设计及优化、涂层制备工艺参数的精细化调控及涂层设备的开发及改进等方面进行了展望。     

内燃机缸体泄漏自动检测系统的研究

泄漏检测对保证内燃机缸体的质量具有重要意义。本文证明了泄漏量和由泄漏所产生的压差间存在比例关系，由此得出泄漏的差压检测法。利用此法，成功地研制了单片微机系统，以完成对内燃机缸体泄漏的自动在线检测。论述并分析了该系统的硬件设计、软件设计以及为使系统在工业现场应用所采取的抗干扰措施。     

超声增强对碱性品绿染料的降解

研究了溶液的pH、铸铁用量及初始浓度对碱性品绿在超声和铸铁联合作用下的降解情况。结果表明,超声的作用有助于提高染料的降解率。在联合作用的下,脱色率都在95%以上,但CODcr的除去率随溶液pH和溶液浓度的增加而减少,随铸铁用量的增加而增加。     

现代珩磨技术综述

现代衍磨技术，特别是长行程内孔珩磨除了尺寸，形状和表面质量修正之外还能对孔进行位置修正。本文根据西欧公司提供的德国Ｇｅｈｒｉｎｇ公司的资料整理与改编。主要内容包括：使用范围及材料，衍磨头与切削层；工件的装夹方式；衍磨工艺方案，摩擦衍磨，清刷珩磨，珩磨机；气缸工作表面的珩磨，不同材料轴承的珩磨等。     

缸体铸件产生异形石墨的原因

对渗漏的缸体进行了解剖,并采样进行力学性能测定和显微组织检验。结果表明,渗漏与异形石墨的存在有明显的相关关系,而碲元素又与异形石墨的产生有关,当碲的加入量(质量分数,下同)为0.002%时,石墨开始发生变异,随着碲加入量的增加,石墨变异程度逐渐严重,当碲的加入量为0.006%时石墨变异非常严重,这种变异的石墨严重降低了铸铁的力学性能,使缸体铸件在气压试验时出现渗漏。     

A new magnetorheological finishing process for ferromagnetic cylindrical honed surfaces

In today’s industries, the internal surface finishing of cylindrical objects is highly demanded to improve their functional performance in various engineering applications. During the traditional honing operation, the finishing forces produced by abrasives on the workpiece surface are not easily controllable and also produce various surface defects. Therefore, to further improve the surface integrity of the traditionally cylindrical honed surface made of ferromagnetic or non-ferromagnetic materials, a new magnetorheological (MR) finishing process has been used with a controlled magnetic field. The experimentation is performed on the honed surface made of gray cast iron, which is generally used as a cylinder liner. The percentage change in surface roughness values, i.e., Ra, Rq and Rz, reduced by 77.44%, 70.16% and 72.16%, respectively, with better improvement in surface after 90 minutes of finishing. The experimental results demonstrated the effectiveness of present process for improving the functional applications of ferromagnetic cylindrical honed surface after removing the various surface defects such as deeper grooves, honing grooves with shaper edges, torn and folded metals, and cavities or holes. The applications of new MR finishing process can also be useful in the internal finishing of injection barrel of a molding machine, cylindrical molds and dies, hydraulic cylinder, etc.     

Tribological properties of twin wire arc spray coated aluminum cylinder liner

The effects of honing process on the friction and wear behaviors of Twin Wire Arc Spray (TWAS) coated aluminum cylinder liners were investigated using a pin-on-reciprocating type of a tribotester. Two types of coated cylinder liners were prepared for the tests: Type I — smooth honing (SH) with ~ 40° honing angle, and Type II — helical structure honing (HSH) with ~ 140° honing angle. The aluminum cylinder liners were coated with an Fe0.8C wire by the TWAS process. In un-lubricated condition, Type II specimen showed lower coefficient of friction (COF) compared to Type I specimen. This result was due to the fact that the groove of Type II was sufficiently large to trap the wear particles that may otherwise contribute to three body abrasive wear. In lubricated condition, Type I showed lower COF due to its lower roughness in comparison to Type II. The experimental results indicate that TWAS process can be effectively utilized for engine applications in conjunction with optimum honing process for the cylinder liner.     

Improved magnetorheological honing process for nanofinishing of variable cylindrical internal surfaces

Improved magnetorheological honing process is developed for nanofinishing of variable cylindrical internal surfaces with better surface integrity. In the present work, finishing performance of existing magnetorheological honing process is enhanced. The present improved process consists magnetorheological honing tool having curved permanent magnet end surfaces. When magnetic field is analyzed using Ansoft Maxwell, the improved magnetorheological honing process results in uniform and higher magnitude of magnetic flux density over its magnetic tool curved end surfaces as compared to the tool having magnetic flat end surfaces. Therefore, an improved magnetorheological honing process has been developed with tool having curved permanent magnet end surfaces. During experimentation, surface roughness values Ra, Rq, and Rz get decreased by 76.28%, 76.67%, and 75.20%, respectively, with improved magnetorheological honing tool having curved end magnetic surfaces, while 47.97%, 46.24%, and 47.08% decreased with tool having flat end magnetic surfaces in same 60 minutes of finishing time. This results in enhancement of finishing performance of the present improved magnetorheological honing process in terms of reduced finishing time and ability to produce good surface integrity. Hence, the present improved magnetorheological honing process performance with tool having curved end magnetic surfaces is found as comparatively better than the finishing tool having flat end permanent magnetic surfaces.     

超声珩齿振动系统的设计方法及其动力学特性

超声辅助珩齿是一项应用前景良好的齿轮精加工方法,其振动系统的设计是关键技术之一。分析了变幅杆和齿轮振动时的耦合关系,对振动系统做了合理简化。在此基础上,结合边界条件,提出一种新的振动系统设计方法,并利用它设计了变幅杆,分析了变幅杆和齿轮的动力学特性。通过与有限元分析及试验结果比较,说明所提出理论模型是完全合理可行的,实例计算结果比有限元分析结果更接近实测值。所获得的结论对超声珩齿振动系统的设计有一定的指导意义。     

Centrifugally cast cylinder lining alloys and their compatibility with cobalt-base and nickel-base hardfacing alloys

Wear- and corrosion-resistant coatings applied to cylinder bores by an in situ melting and centrifugal casting process are widely used in plastics processing machinery. Cylinder lining alloys and the method of manufacturing bimetallic cylinders with these alloys are described. One primary cause of cylinder wear is an internal screw which can bear heavily against the cylinder bore. Since the screw flights are often hardsurfaced with cobalt-base or nickel-base alloys, Alpha LFW-1 wear tests were made to evaluate the relative wear resistance of these alloys and their compatibility with centrifugally cast cylinder lining alloys. The results indicate preferred hardfacing materials and application processes for use with each lining alloy.     

超声珩齿圆锥形变幅器动力学特性

为获取非谐振单元超声珩齿变幅器动力学特性,根据Mindlin理论及建立的变幅杆和中厚圆环板的力耦合条件,推导了变幅器的频率方程和位移振幅方程,利用MATLAB软件求出了变幅器设计参数和位移振幅的数值解。有限元分析及动力学实验得到的谐振频率和位移振幅与数值解一致。     

A novel magnetorheological honing process for nano-finishing of variable cylindrical internal surfaces

A novel magnetorheological honing process is designed and developed for nano-finishing of cylindrical internal surfaces with the help of permanent magnets. The radial movement of magnetic tool surface is adjusted as per the internal diameter of different cylindrical components and make it fixed before start of finishing so that it can maintain constant working gap while perform finishing. The present developed magnetic tool surface always constitutes higher magnetic field than the inner surface of ferromagnetic or non-ferromagnetic cylindrical workpiece. This is an important requirement to finish the internal surface of ferromagnetic or non-ferromagnetic cylindrical components because it ensures MR polishing fluid cannot stick on the workpiece surface while performing the finishing. Hence, present developed process is useful for finishing of ferromagnetic cylindrical molds, dies, hydraulic actuators, etc. for its better functional applications after the conventional honing or grinding process. The internal surface roughness of cylindrical ferromagnetic workpiece is dropped to 90?nm from its initial value of 360?nm in 100 minutes of finishing. Further scanning electron microscopy has also been done to understand the surface characteristics of finished workpiece. The results revealed that the developed magnetorheological honing process is capable to perform nano-finishing of internal surface of the ferromagnetic cylindrical components.     

超声珩齿振动系统动力学特性分析与仿真

为研究超声珩齿振动系统的非谐振设计,通过MATLAB软件对振动系统的动力学频率方程进行求解,分析了变幅杆设计长度和变幅器振动频率对频率方程解误差的影响,并得出一组变幅器的设计参数。为验证非谐振设计方法的可行性,通过ANSYS模态分析,能使变幅器的谐振频率与理论设计的结果基本一致。     

发动机缸体缸盖的铸造

对国内外发动机缸体、缸盖铸造生产进行了总结,其材质主要以C(质量分数,下同):3.15%～3.3%,CE:3.95%～4.05%,Si/C:0.6%～0.7%的灰铸铁为主。一般选择冲天炉-有芯工频电炉进行熔炼,孕育剂仍普遍采用75SiFe,立浇底注式浇注系统和保温冒口有利于获得优质缸体、缸盖,冷芯制芯工艺已逐渐取代热芯工艺。通过提高浇注温度、型砂紧实率等措施可减少缸体、缸盖常见缺陷渗漏的出现。