双定子轴向力偶型柱塞马达的转矩特性分析

为解决传统轴向柱塞马达轴向力不平衡、输出效率低的问题,从扭矩大小、波动率和柱塞工作效率等方面开展研究,结合双定子原理提出双定子轴向力偶型柱塞马达。该马达通过特殊的结构使力偶转矩输出,实现轴向力平衡。通过传统轴向柱塞马达和双定子轴向力偶型柱塞马达各自柱塞的受力情况,推导了该马达单个柱塞组件产生的瞬时理论转矩,借助MATLAB编程,对比分析了传统轴向柱塞马达与该马达的输出转矩,结果显示传统轴向柱塞马达输出转矩为11.59~11.89 N·m,而该马达输出转矩为23.33~23.63 N·m,比传统轴向柱塞马达的输出转矩增加了近1倍,转矩波动降低为原来一半,柱塞的工作效率增加了1倍,并通过试验得出该马达的机械效率和容积效率,验证了原理的合理性,为后续相关研究奠定了基础。     

单泵驱动摆动多路马达传动系统输出特性

摆动多路马达通过设置双定子和增加作用数,在一个壳体里面形成了多个相互独立、互不干扰的马达,可以实现多输出。以单泵和摆动多路马达为基础建立传动系统,理论探讨该传动系统中摆动马达输出转速和转矩的多样性。以双定子双作用摆动多路马达为例,通过数学推导得出马达不同连接方式下的转速和转矩公式,并运用MATLAB进行分析。研究结果表明：普通连接方式下单泵驱动的双定子双作用摆动多路马达具有8种转矩和转速输出,在差动情况下有4种转速和转矩输出。并进一步论证了单泵驱动下双定子N作用摆动多路马达在普通连接情况下有N2+2N种转速和转矩输出,在差动连接下有N2种转速和转矩输出。     

双定子泵对多输出齿轮马达传动特性的分析

为了使定量泵输出多级定流量、不用减压阀实现一泵多压,定量马达实现多级定转速、转矩,设计了双定子泵和多输出齿轮马达,同时提出了双定子泵对多输出齿轮马达传动系统。在规定了元件的职能符号之后,分别以双作用双定子泵与1-3型多输出齿轮马达为例,分析了双定子泵和多输出齿轮马达在不同工作方式下的输出特性,得出了B-A型多输出齿轮马达的工作方式、双定子泵输出流量和多输出齿轮马达输出转速、转矩的一般公式。同时,探讨了排量系数对输出特性的影响。结果表明:通过改变多泵、多马达的连接方式,实现了液压传动系统多级定转速、定转矩的输出,扩大了输出的范围,为新型液压传动系统的应用提供了依据。     

内外啮合齿轮泵与马达传动的特性分析

为了实现齿轮泵输出流量的定级变化、齿轮马达输出转矩和转速的定级变化,设计了内外啮合型齿轮泵和马达,将内外啮合齿轮泵和马达组成传动系统。以内3外2型为例,对内外啮合型齿轮泵和马达的原理进行了分析:泵具有5个独立的油液输出口,通过不同组合可以组成11中不同的供油方式;马达有5个进油口,在普通连接下可以输出11种转矩与转速,在差动连接下可以输出6种转矩与转速。分析结果表明:在内外啮合齿轮泵和马达的传动系统中,通过改变泵的供油组合方式、马达的连接方式,可以定级的改变马达转矩与转速,拓宽了齿轮泵和马达的适应领域。     

双定子马达滚柱受力特性分析与实验研究

为了寻求具有滚柱受力小、间隙补偿能力强的双定子马达叶片结构，改善双定子叶片液压马达运行的平稳性，提出一种U形连杆槽结构。对双定子液压多速马达4种不同工作方式下的滚柱受力特性进行分析，推导出滚柱与连杆槽之间的摩擦力与滚柱偏转角、槽型夹角的关系，从而得到滚柱磨损量对各接触面正压力的影响。同时还进行了实验研究。结果表明：具有U形连杆槽的叶片结构不仅可以改善滚柱与连杆之间的应力状态，还可以使滚柱与各接触面之间的正压力的变化率趋于稳定。     

定转子双开槽对永磁同步电机齿槽转矩的影响

针对内置式永磁同步电机齿槽转矩过高导致的振动和噪声的问题,提出一种定子开矩形槽转子开弧形槽的电机模型,可以在不牺牲输出转矩的情况下抑制齿槽转矩。在分析齿槽转矩的基础上,以8极36槽内置式永磁同步电机为例,通过有限元仿真,分析在定转子上单独开辅助槽以及同时开辅助槽时,电机齿槽转矩随辅助槽参数的变化。然后对优化前后电机的性能参数进行对比,验证了所提方法的可行性。仿真结果表明,齿槽转矩随辅助槽参数的变化先减小后变大,定转子同时开辅助槽时,齿槽转矩削弱了92.01%,相较于单独在定子或转子开槽,可以更好地削弱电机齿槽转矩,且双开槽模型可以更有效地削弱气隙磁密谐波,提高电机的输出转矩。     

新型大力矩压电马达的实验研究与分析

压电马达是一种利用压电晶体逆压电效应获得驱动力矩的新原理微特电机,它与由电磁作用获得转矩的电磁马达工作原理截然不同.文章在行波接触型马达基础上提出了一种新型行波锥面驱动大力矩压电马达,它不同于以往马达定转子之间动态过程中为点接触的结构形式,采用了定转子之间动态过程为线接触的新型结构.文中给出了马达的结构及激励方法,讨论了选取压电材料的原则;并用有限元方法分析了马达定子的工作模态,通过实验得到了此种新型马达的动态特性.     

双作用叶片油泵的改进设计

双作用叶片油泵由于叶片在吸油区所受到的液体推力不平衡,在叶片和定子之间摩擦严重,影响了油泵的效率和寿命。本文研究设计了一种新型双作用叶片油泵,通过改变叶片与配流盘的结构设计,不仅能使叶片在吸油区卸荷,同时还采取了安全措施,使叶片能够与定子可靠接触,提高油泵的工作压力、使用寿命和效率,降低噪声,并使其工作安全可靠。     

液压马达测试平台有限元分析与优化设计

以液压马达测试平台为主要研究对象,设计一种适用于多种型号马达的安装结构,利用ANSYS Workbench建立结构的有限元模型,对模型进行静力学分析和模态分析,得到螺栓预紧力与转矩载荷作用下的结构静力学性能、固有频率及振型。通过中心复合实验设计和响应曲面分析,总结出支架厚度、肋板厚度、螺栓预紧力和转矩等参数对结构强度、刚度以及固有频率的影响规律,找出合理的设计参数完成结构优化设计。     

双作用叶片泵噪声的产生机理和降噪分析

主要分析了影响双作用叶片泵噪声的因素.对定子过渡曲线、工作容腔压力切换和叶片径向激振力等主要因素做了深入研究.针对双作用叶片泵出现的噪声问题进行探讨,并提出了降低叶片泵噪声的相关途径.     

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。