利用磁性流体的静压螺旋装置：—专利应用新技术

1 一般的螺旋装置在机械装置中,螺旋传动是一个很重要的机构,螺旋装置有各种形式,因而被广泛采用。其中滑动螺旋结构简单,加工方便,但采用这种传动机构时,由于内、外螺纹滑动摩擦而产生的阻力大,因而传动效率低。为弥补这一缺点,把刚体之间的滑动改变成滚动的滚珠螺旋机构,为防止刚体接触,在     

2-RRU&RSR并联机构运动学传动性能分析

以2-RRURSR并联机构为研究对象,通过矢量方程法对机构进行位置逆解研究,得到相应的运动学方程。利用螺旋理论建立机构的雅可比矩阵,并通过对机构支链输出传动效率指数的定义对机构的运动学传动性能进行研究。     

一种螺旋齿轮传动机构的磨损分析与改进

讨论了EQ3126型汽车发动机中螺旋齿轮在实际应用中存在的磨损问题,经研究发现该发动机内凸轮轴-机油泵驱动轴的齿轮副螺旋角分配不合理,发动机的主动齿轮轴和齿轮的尺寸都明显大于从动的机油泵驱动轴齿轮的尺寸,使两者形成理论上的增速传统机构,其传动效率会相应降低,主动轮轮齿会受到较大阻力,给传动增加了困难;其次是齿轮副的材料搭配不当,从而导致齿轮磨损严重。经过应力求解得到,该螺旋齿轮传动的齿面接触应力大大超过了允许的极限疲劳应力。接着提出了几点改进建议,如重新设计齿轮参数、修改材料配对、控制齿轮加工质量和改善润滑条件,对改善该传动机构中螺旋齿轮的工作环境以及解决齿面磨损问题提供了参考。     

车用无级变速器阿基米德螺旋面自适应加压机构研究

根据赫兹接触理论,对所提出的车用类球面无级变速器中的阿基米德螺旋面加压机构的自适应性能进行分析及计算,并与钢球V形槽加压机构做了分析与对比;探讨了加压螺旋面螺旋升角的最佳取值范围。结果表明:该加压机构的传动系数比钢球V形槽加压机构有明显的下降,可避免钢球V形槽加压产生的强烈冲击而导致的加压失效状况,有效提高变速器的承载能力,自适应加压性能更优异。此外,采用ABAQUS软件的分析方法,对该加压机构在汽车整个行驶工况下的接触应力进行了计算和分析。验证了该加压机构的强度足以满足设计要求。     

螺旋缝焊管铣边机的应用及改进

阐述螺旋缝焊管生产时带钢边缘加工装备的发展历程。介绍目前广泛应用的铣边机的结构形式、工作原理、性能特点以及运用情况,分析螺旋缝焊管铣边机在使用过程中存在的问题和不足,诸如压下机构、主传动轴、升降托辊机构等,制定改进措施。改进后使用效果良好。     

棘轮离合器疲劳裂纹原因分析

棘轮离合器是超越离合器的一种，具有尺寸小、重量轻、承载能力高、传动平稳、寿命长、啮合可靠性高的特点，在航空发动机传动系统中应用十分广泛。本研究分析了发动机起动不成功的故障现象，根据故障树分析方法查找故障原因，阐述了棘轮离合器工作原理，详细分析了故障产生的原因。结果表明:发动机起动不成功的主要原因是双速传动机构失效，棘爪疲劳裂纹是导致双速传动机构失效的主要原因，棘爪产生疲劳裂纹是棘爪存在制造缺陷和S含量超标，提出了改进方法和预防措施，对发动机的修理具有参考价值。     

大型螺旋锥齿轮的加工

螺旋锥齿轮比直齿锥齿轮有重合系数大、传动平稳、承载能力高、寿命长等优点,大型螺旋锥齿在重型机器上广泛使用,我厂承担的650连轧机制造中,就有六对螺旋锥齿轮。锥齿轮的大端端面模数为34～36毫米,直径为1462～2481毫米,外锥距为1411～1612毫米。对于制造这样大型的螺旋锥齿轮,将一台精度失效的5米圆柱齿轮铣齿机改装成用指形铣刀加工大型直齿锥齿轮和螺旋齿锥齿轮的机床,改装后的铣齿     

油缸式自动内外螺纹脱模注射模设计

针对带有内螺纹的阀体,设计了螺旋传动自动脱离螺纹的注射模。脱模机构设计合理、动作可靠、稳定性较高,完全符合该产品技术要求,为同类型的模具设计有一定的参考作用。     

螺旋齿圆柱齿轮齿面结构的数字化模型研究

螺旋齿圆柱齿轮与螺旋齿面齿轮进行啮合传动时,其传动性能优于直齿面齿轮和斜齿面齿轮传动副.提出基于啮合原理构建螺旋齿圆柱齿轮齿面结构的方法,研究了螺旋齿圆柱齿轮的切削成形理论,建立了螺旋齿圆柱齿轮的切削模型,并构建了螺旋齿圆柱齿轮齿面结构的数字化模型.     

英国Brooke Tool Automation公司机械动力头

Brooke 公司的凸轮进给机械动力头是属于小功率箱体移动式动力头。主要用于单轴加工。机构比较简单,其传动系统如图1。动力头用一个电动机驱动。电动机经一对圆柱齿轮减速传动主轴回转。在箱体内装在主轴前部的一对螺旋齿轮 A 传动与主轴垂直的交换齿轮轴。经一对交换齿轮 B,通过蜗杆蜗轮副 C 传动套装在主轴上的圆柱凸轮     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.