考虑啮合错位的斜齿轮复合修形优化研究

为了减少斜齿轮传动因啮合错位导致的齿面偏载、传递误差增大、啮合冲击增大,研究考虑啮合错位的斜齿轮复合修形方法,讨论修形前后不同错位量下齿面啮合性能的变化规律。该方法考虑了啮合错位对齿轮啮合性能的影响,基于斜齿轮啮合接触计算模型,以齿面载荷分布、传递误差、啮合冲击等性能指标为评价依据,进行了“螺旋角修形+齿廓鼓形修形”的复合修形。结果表明：基于多目标的“螺旋角修形+齿廓鼓形修形”复合修形能有效改善因啮合错位造成的齿向偏载,且在降低传动误差峰峰值和改善啮合冲击方面显著优于单一的螺旋角修形,能较全面地改善斜齿轮的啮合质量。     

泵用齿轮副根切重合度的公式创建

为满足外啮合齿轮泵根切齿轮副的设计需要,基于滚齿加工原理,由创建根切半径的计算公式起,推导出一套完整的根切重合度计算公式,据此分析了基本参数对该根切重合度的影响,所得结果由根切齿轮副的三维虚拟模型加以验证。结果表明,根切会使主动齿轮的齿顶点可能进入不了啮合,目前常用齿顶重合度代替根切重合度的计算方法不可靠;除模数外的其它齿形基本参数对根切重合度均有影响,其中变位系数的影响最大;采用齿条刀具的最佳齿顶圆角半径,可以保证根切重合度等于齿顶重合度;当实际的根切重合度过大时,通过降低齿条刀具齿顶圆角半径,可以改善齿轮副的传动质量等。所得根切重合度公式也能为其他常规的根切齿轮副设计,提供一种新的方法。     

典型故障对直齿轮啮合刚度的影响

以外啮合圆柱直齿轮为研究对象,采用有限元法计算典型故障齿的啮合刚度,分析故障齿齿面应力分布特征以及主动轮的齿向载荷分配,研究含齿根裂纹、齿面断裂、齿面点蚀故障的齿轮副对啮合刚度的影响以及载荷变化引起的裂纹故障齿的啮合刚度的变化。分析结果表明:贯通裂纹齿啮合刚度相比斜裂纹齿啮合刚度变化明显,单齿啮合刚度变化更为突出;载荷较小时裂纹故障齿啮合刚度随载荷增大而增大,载荷超过一定值后啮合刚度趋于定值;齿面断裂面的大小严重影响齿轮啮合刚度。     

基于精确建模的微线段齿轮弯曲强度理论分析

提出了一种微线段齿轮精确建模方法。该方法通过建立齿轮轮廓方程和齿根过渡曲线方程,编程求出微线段全齿廓的坐标点,并利用PRO/E建立微线段齿轮的齿形模型,最后导入到Ansys中进行齿根弯曲强度分析。结果表明,齿根过渡曲线对齿轮齿根的弯曲强度大小有直接影响。该文所述方法提高了微线段齿轮齿根弯曲强度计算的准确性。     

裂纹工况下斜齿轮系统啮合刚度计算模型研究

当斜齿轮副产生裂纹时,会影响齿轮副的啮合刚度。为了获得更准确的裂纹斜齿轮副的啮合刚度,提出一种改进的裂纹斜齿轮啮合刚度计算模型,综合考虑轮齿刚度、齿轮基础刚度在横向和轴向的影响,研究了齿顶扩展裂纹和端面扩展裂纹两种典型裂纹工况下的齿轮系统啮合刚度,并将啮合刚度解析计算结果与有限元模拟结果进行了对比。结果表明：啮合刚度的降低程度主要与裂纹区域有关,裂纹区域越大,啮合刚度降低越大;在裂缝长度和深度相同的情况下,端面扩展裂纹对啮合刚度的影响比顶部扩展裂纹更显著。仿真结果与计算结果吻合较好,验证了所提方法的准确性和有效性。     

平顶齿轮原理切制弧齿锥齿轮接触斑点分析

本文分析了用平顶齿轮原理切制弧齿锥齿轮时，对齿轮啮合质量有着直接影响的齿面接触斑点误差产生的原因，并提出了修正方法，以利于弧齿锥齿轮的设计计算。     

直齿面齿轮增量制造技术研究

直齿面齿轮是一种平面齿圈齿轮,通常与直齿圆柱齿轮相啮合。由于其独特的啮合方式,所以直齿面齿轮不仅被用于传递相交轴线的运动和动力,而且相比于传统齿轮(如圆柱齿轮、圆锥齿轮)还具有重合度高、传动平稳、噪声低、扭矩分流效果好等传动优势,这些优势使得直齿面齿轮被广泛应用在低速和高速、轻载和重载的众多传动领域中。研究采用快速成型技术制造直齿面齿轮,并讨论模型的收缩率等问题。     

斜齿偏置非正交面齿轮的齿面建模及插齿仿真

为了促进面齿轮适用于多种空间布局的传动场合,扩大面齿轮在传动领域的应用优势,推导了斜齿偏置非正交面齿轮齿面方程,并使用VERICUT软件完成了斜齿偏置非正交面齿轮插齿仿真加工。由齿轮啮合原理,推导斜齿偏置非正交面齿轮方程,计算出面齿轮齿面点坐标;在三维软件中构建机床模型、刀具和加工毛坯,导入VERICUT中,编写相应的数控加工程序,完成插齿加工仿真;在加工模型上提取坐标点,与计算得到相对应的坐标点进行齿面偏差分析。结果显示：插齿仿真加工齿面没有产生过切,插齿仿真加工齿面最大残留为7.4 μm,最小残留为3.3 μm,验证了数控插齿加工斜齿偏置非正交面齿轮的正确性。     

具有汉字输出功能的国标齿轮设计软件

本文提供了一个可以在微型机上应用的齿轮设计软件PGBOX。本程序用于计算基本齿廓符合GBl356—78的内、外啮合直齿轮和斜齿轮、标准齿轮和变位齿轮构成的圆柱定轴轮系及行星轮系。程序操作极为简便,可大大提高齿轮计算的速度和精度。     

基于I—DEAS虚拟环境少齿数圆柱齿轮分析系统研究

本文利用I—DEAS新型软件多种功能，在对少齿数斜齿轮三维参数化建模的基础上，进行了斜齿轮干涉、根切现象的啮合分析和齿面接触、齿根弯曲最大应力的有限元分忻。构建了一种少内数网佳齿轮啮合状况和承载能力的检测和动态仿真系统。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.