内燃机缸套激光珩磨技术及其性能试验研究

激光表面微造型技术是改善摩擦副表面摩擦学性能的有效途径之一。基于声光调Q技术的二极管泵浦固体光源（DPSS）Nd:YAG激光器,采用“单脉冲同点间隔多次”激光微加工工艺,对CA6DF2-26型柴油机气缸套内孔表面进行激光珩磨加工。加工出的缸套网纹参数具有较好的一致性,达到了主机厂的技术要求。进行了激光珩磨缸套的台架综合性能试验研究,结果表明,采用激光珩磨缸套的发动机,其功率、扭矩、燃油消耗指标保持稳定,与采用传统平台珩磨网纹缸套的发动机相比,柴油机的机油油耗降低53％,漏气量降低近50％。     

内燃机气缸孔表面微织构设计与摩擦性能模拟试验

为提高内燃机气缸孔的使用寿命,根据气缸孔/活塞摩擦副往复运动的特点,采用0.10、0.30、0.50三种织构密度,设计出气缸孔表面两组不同密度组合形式,采用ZY型电路板制作机,在模拟气缸孔的钢块试样表面上分段织构出不同密度的微凹坑,与模拟活塞的钢销试样组成面对面摩擦副进行往复运动摩擦试验。结果表明:气缸孔两组不同密度组合形式表面摩擦系数均随着试验速度的升高而下降,且大多趋于平稳;中间区域织构密度高,两端区域织构密度低组合形式起增摩作用;中间区域织构密度大,两端区域织构密度低组合形式,低速相对运动时减摩效果不太明显,高速时减摩效果显著增强,0.30+0.10+0.30密度组合形式减磨效果较佳,当运动速度分别为0.10m/s、0.20m/s时,气缸孔摩擦系数相对无织构表面分别降低了19.3%和30%。     

发动机气缸孔变形测量研究

发动机的气缸是发动机的重要组成部分，如果这个气缸孔发生变形就会对柴油机整机性能造成非常大的影响。在本文中通过分析柴油机气缸孔变形的原因，采用相关的测量方法，对气缸整个系统进行测量，以便对气缸孔的变形进行相应的研究，通过对气缸孔的变形进行检测和分析，提出了一些解决办法，为以后的改进工作打下了坚实的基础。     

一种超微造型的气缸套及其制备方法

一种超微造型的气缸套及其制备方法,气缸套内孔从上至下分为Ⅰ区、Ⅱ区、Ⅲ区,所述Ⅰ区起始于活塞运动的上止点,Ⅱ区为活塞运动的冲程中部,Ⅲ区起始于活塞运动的下止点至缸套底端,气缸套内壁有激光刻啄的超微网纹沟槽,相邻网纹呈错位螺旋分布;经过激光刻啄,缸套内孔表面沟槽结构均匀,槽深一致稳定性高,缸套表面光滑,可有效避免拉缸,降低活塞环与缸套内孔的摩擦磨损量,进而降低油耗,延长缸套使用寿命。     

304不锈钢激光焊接匙孔瞬态行为分析

针对激光焊接过程匙孔瞬态行为难以观察的问题,建立了304不锈钢激光焊接过程熔池和匙孔之间瞬态耦合的三维模型,开展了匙孔瞬态行为研究。采用了光线追踪热源描述激光能量分布,涉及了流体流动、蒸发潜热、Marangoni剪切力、反冲压力和表面张力等各种物理因素;通过304不锈钢激光焊接试验对所建模型进行了验证,模拟的焊缝横截面形貌与试验结果吻合较好,表明所提出的模型能够反映激光焊接过程;基于模拟结果图像,提取了焊件纵截面和焊件上表面的匙孔特征信息,对匙孔瞬态行为进行了分析。研究结果表明:匙孔瞬态行为受气泡影响,纵截面上匙孔面积因气泡破裂而增大;焊件上表面匙孔开口长度与匙孔后壁倾角相关;与匙孔开口宽度相比,匙孔纵截面上面积和匙孔长度变化幅度更大。     

制冷压缩机气缸内壁激光表面处理研究

通过对2F6．3型制冷压缩机气红内壁作激光表面处理的试验研究，探索了处理后材料表面硬度、耐磨性、金相组织及压缩机功耗改善情况，得出了用高能激光束扫描气缸内壁进行表面处理的若干装机试验结果。     

激光磨抛复合强化对15CrMnMoVA钢孔结构疲劳性能的影响研究

对15CrMnMoVA钢试件孔结构采用了坐标磨、数控磨抛和激光磨抛复合强化等不同工艺进行加工,分析其表面完整性特征,并对试件进行对称循环加速疲劳寿命试验。结果表明,试件孔结构的疲劳破坏机制为微动疲劳,增加孔的倒角尺寸会导致疲劳寿命降低;与传统的坐标磨工艺相比,数控磨抛工艺可以提高疲劳极限5%,而激光强化与数控磨抛复合工艺可以提高疲劳极限20%;激光强化能形成较深的残余压应力强化层,数控磨抛后残余压应力层仍然深达0.5 mm;数控磨抛可以提高孔的形状精度至0.009 mm,并进一步将孔壁抛光至镜面(表面粗糙度为Ra 0.018μm);激光磨抛复合强化工艺显著提高了孔结构的疲劳性能。     

柴油机气缸孔压板珩磨工艺改进

为了解决因气缸孔形状误差导致活塞漏气量大和烧机油的问题,气缸孔压板珩磨技术已经被广泛地应用。本文分析了压板珩磨工艺的有效性因素,改进了工艺流程。柴油机气缸体气缸孔的加工方式有两种。一种是气缸孔设计在气缸套中,气缸孔加工完成后,将气缸套压入气缸体中;另一种是气缸孔设计在气缸体中,气缸孔在气缸体毛坯中金属加工形成。本文研究的气缸孔压板珩磨有效性属于第二种。     

打壳机气缸内孔加工装置设计

近年来我国机械制造加工业飞速迅猛的发展对我国的机制机加行业,尤其是对机加加工的质量提出了越来越高的要求.打壳机气缸内孔加工质量要求高,刚度极低,生产技术难度大,通过设计专用加工装置较好的解决了这一问题.专门为打壳机气缸内孔加工装置做了一次设计,利用普通车床加工出满足相关表面要求的内孔.介绍了深孔加工发展历程,对打壳机气缸缸体进行了加工工艺的分析,根据工件工艺规程需要,设计了镗缸体内孔所需的加工装置;对加工装置进行了结构设计,采用了前后倒顶尖的装卡结构和定位方式,定心效果良好,避免了装卡变形;镗头部位还加了支撑,刀杆内部做了两条通道以便通切削液和压缩空气以解决了深孔加工的排屑、导向、冷却的三大问题;并对加工装置中主要零件镗杆进行了受力分析,并对镗杆进行稳定性计算.这样的加工装置不仅保证了相关技术与要求,还使得其可轻而易举的在车床上完成.     

缸套内孔表面的深沟平台网纹及加工工艺

缸套内孔表面的深沟平台网纹及加工工艺柳州市南方汽车缸套厂彭兴琪一、前言气缸套内孔表面质量直接影响到发动机的使用寿命、可靠性、经济性及机油油耗等。以前大家都认为缸套内孔的表面粗糙度越小越好，但事实证明并非象我们认为的这样。相反缸套内孔表面的粗糙度小到一...     

激光微造型表面摩擦磨损性能研究

采用声光调Q二级管泵浦固体光源（DPSS）Nd：YAG激光器对缸套试件表面进行了,微造型州纹加工。在往复式活塞环-缸套摩擦磨损模拟试验机上进行了激光造型缸套试件与未造型光滑缸套试件的摩擦磨损性能对比试验研究。试验结果表明,在重载高速条件下,激光网纹试件与未造型试件相比,摩擦因数降低23％,磨损量降低66％。说明激光网纹沟槽具有贮油、积屑和动压润滑作用,同时激光加工的网纹淬火效应也有利于提高支承表面的耐磨抗擦伤性能。     

Surface topography and tribology of cast iron in boundary lubrication

This work aims to study and understand the influence of the surface topography on wear of grey cast iron used for heavy duty diesel engine cylinder liners. A micro-alloyed grey cast iron was tested with different surface topographies. These were polished surfaces, honed surfaces (with two different honing parameters) and three model surfaces with well defined grooves on a polished specimen.Reciprocating friction tests using a steel ball rubbing against a flat or a cylindrical sample (extracted from a cylinder liner) were carried out on a Cameron Plint test rig. A commercial synthetic oil for diesel engine was used as the lubricant. The friction coefficient and the electrical contact resistance were measured during the tests. The wear volume of the cylinder liner part was also measured at the end of the test.The influence of the surface topography on the tribochemical film formation and on the wear behaviour of cast iron was established. Surfaces exhibiting lots of surface asperities had the highest wear, mainly due to delayed formation of protective tribochemical film. In our test conditions, the spacing between the grooves on model specimens had no influence on the wear behaviour of the cast iron specimens.     

Lubricated friction of laser micro-patterned sapphire flats

The technique of laser ablation was employed to create groove-type patterns of different dimensions on sapphire flats. A thin film of a liquid lubricant was deposited on the patterned surface. Comparative pin-on-disk tests revealed a pronounced effect of the pattern on the tribological characteristics of the flats. The presence of the grooves drastically extended the sliding life. If the grooves were too large, the sliding life was limited by excessive wear of the steel ball, while with sufficiently fine grooves, a steady-state regime with an exceptionally low friction coefficient was approached, after an extended run-in period. This revised version was published online in August 2006 with corrections to the Cover Date.     

Structural aspects of European and American diesel engine piston deposits

The formation of carbonaceous deposits on upper lands and ring grooves of diesel pistons is believed to be at least partially responsible for excessive cylinder bore wear and loss of oil control in field service. A properly formulated diesel lubricant has, among other performance characteristics, the ability to control piston deposits, thereby improving overall engine performance.     

Comparing laser and polychromatic confocal optical displacement sensors for the 3D measurement of cylindrical artefacts containing microscopic grooved structures

A scanning system has been developed for measuring the surface of early cylinder mechanical sound recordings to high precision, both for surface preservation and for post-processing of the data to recover the sound encoded in the grooves. Research has identified that high sensor axial resolution is required to resolve the smallest amplitude groove modulations contained on typical cylinder artefacts resulting in the selection of confocal laser and white light (polychromatic) confocal sensors as suitable sensing technologies. This paper presents data acquired by the two confocal sensor technologies, comparing the measured surface profiles with data obtained using a stylus profilometer. We investigate limitations of the sensors, relating their characteristics to the ongoing development of the scanning system.     

缸孔珩磨工艺及表面特征参数浅析

珩磨作为缸孔加工方法,因能修正前道工序产生的几何形状误差和表面波度误差,通过在缸孔表面形成细小的沟槽,这些沟槽有规律地排列形成网纹,并由专门的珩磨工艺削掉沟槽的尖峰,形成微小的平台,平台保证承载,原硬度保证耐磨,而被广泛应用。根据我公司所使用的美国NAGEL珩磨机,介绍了珩磨缸孔后表面质量的评定理论及工艺,并对影响其表面特征参数的因素进行了简要的分析。     

Molecular Dynamics Simulation of Thermal-Induced Local Heating and Depletion of Ultrathin Perfluoropolyether Lubricant Under Moving Laser Heating

Molecular dynamics simulations of nanostructured perfluoropolyether lubricant are performed to investigate localized heating and lubricant depletion instability under moving laser heating. The evolution of the lubricant surface morphology indicates that a valley-like depletion track is formed along the path of the laser beam, resulting in aggravated depletion with heating time. The depletion profiles at various laser durations are characterized by the film thickness, in which a raised ridge is formed around the depletion zone signifying that the thermocapillary stress has a non-negligible effect on lubricant depletion. The recovery process is studied as well by further equilibrating the entire system with the laser beam turned off. During the cooling stage, the lubricant undergoes a slow recovery when compared with the laser-induced depletion. In addition to the attractive lubricant-to-disk interaction, the strong polar coupling between end beads prevents the recovery of lubricant beads back to the depleted surface. Moreover, the nonuniform surface tension and the nonequilibrium thermocapillary stress are expected to account for the mechanisms of lubricant depletion under moving laser heating.     

Molecular dynamics studies of lubricant depletion under moving laser heating: Effects of laser power and film thickness

Molecular dynamics simulation is employed to study the depletion behaviors of perfluoro-lubricants under scanning laser heating for heat-assisted magnetic recording hard disk drives. A partial lubricant near the substrate is irradiated by the laser beam to mimic nano-scale heat transfer from disk to lubricant. The lubricant surface morphology and thickness profiles are examined to reveal the dynamic depletion behaviors. The localized temperature evolution is also evaluated to illustrate the direction-dependent ridge formation around the depletion zone. In addition, the effects of laser power and film thickness on lubricant depletion are explored. Although evaporation is enhanced significantly at high laser powers or for lubricant with thickness around one monolayer, thermodiffusion is the primary mode of lubricant depletion under scanning laser heating.     

金属陶瓷添加剂对船舶主机汽缸套-活塞环摩擦学行为的影响

将普通CD40润滑油作为基础润滑油，在3种不同的载荷作用下，对含有金属陶瓷添加剂润滑油对汽缸套-活塞环摩擦磨损特性的影响进行了模拟试验研究，并与实际使用的普通CD40润滑油的试验结果进行了比较。研究结果表明，汽缸套-活塞环摩擦副在这种添加剂作用下，其磨损失重及摩擦因数都大幅度降低。摩擦副表面扫描电镜分析结果也表明，这种添加剂使摩擦表面更光滑，其本身具有表面自修复作用。     

Study on Lubricant Depletion Induced by Laser Heating in Thermally Assisted Magnetic Recording Systems: Effect of Lubricant Thickness and Bonding Ratio

In this study, we have carried out fundamental research on lubricant depletion due to laser heating in thermally assisted magnetic recording. In particular, we investigated the effects of lubricant film thickness and lubricant bonding ratio on lubricant depletion. Conventional lubricants Zdol2000 and Ztetraol2000 were used. The lubricant depletion characteristics due to laser heating were found to depend largely on the lubricant film thickness and material. That is, for films thicker than one monolayer, the lubricant depletion depth increased with the laser-irradiation duration, whereas the thickness of the lubricant after laser irradiation on the diamond-like carbon (DLC) films tended to remain at a constant film thickness of one monolayer. The lubricant depletion width gradually increased as the laser irradiation duration increased. The increasing trends for the lubricant depletion width were quantitatively very similar and almost independent of the initial lubricant film thickness. However, for lubricant films with thicknesses less than one monolayer, the lubricant depletion depth was very small. The lubricant depletion width increased remarkably to several hundred micrometers as the laser irradiation duration increased. The lubricant depletion depth and width were much smaller for Ztetraol2000 than Zdol2000. In addition, the lubricant-bonding ratio was found to greatly affect the lubricant depletion characteristics due to laser heating. In other words, the lubricant depletion depth and width decreased as the bonding ratio increased. The lubricant depletion mechanism involves the evaporation of mobile lubricant molecules when the maximum attained temperature is less than 100 °C. Another suggested lubricant depletion mechanism involves the thermocapillary stress effect, which is induced by the disk surface temperature gradient resulting from the non-uniformity of the laser spot intensity distribution.