RV减速器中摆线轮齿形优化修形与参数化设计

为了得到符合实际工作要求的摆线轮齿形,对摆线轮齿形的几种修形方式进行了研究,确定了最佳修形方式为负移距与正等距相组合的修形方式。对多种优化方法进行了分析,选取了两点外插的混合罚函数法来求解,并借助VC++6.0编写绘图程序验证了此种修形方式的合理性。同时利用Pro/E 4.0对摆线轮进行了参数化设计,推导出摆线轮齿廓曲线上的坐标点按齿廓曲线曲率不同分布疏密程度不同的公式,同时借助VC++6.0编制程序计算出摆线轮齿廓曲线上分布的各点的坐标值,为使用数控机床加工摆线轮提供了便利。     

RV减速器摆线针轮齿廓修形回差影响分析

针对RV减速器回差精度问题,建立了摆线针轮齿廓修形的回差精度数值分析模型,采用几何法求解各种常见修形方式产生的几何回差,同时考虑摆线针轮传动中的弹性回差,推导出摆线轮齿廓修形的回差影响公式,并讨论了同一摆线轮齿廓修形方式下不同的修形参数与同一修形参数下不同的修形方式对回差的影响,得出在同一修形量的条件下,等距加移距的组合修形方式的回差影响最小,移距修形的回差影响最大。对RV-40E型减速器样机进行试验验证,与传统回差公式相比较,文章推导的回差公式精度提高6%左右。     

摆线针轮传动中摆线轮齿廓修形技术研究

为确定不同传动要求的摆线针轮传动机构中摆线轮齿廓修形方式及最佳的优化算法,首先对摆线针轮传动中摆线轮齿廓应用最多的"正等距+负移距"和"负等距+正移距"两种组合修形方式进行了分析计算,得到了两种组合修形方式引起的回差大小及修形后摆线轮啮合受力的优劣,确定了不同传动要求的摆线针轮传动机构优先适用的修形方式;对摆线轮齿廓优化算法进行了对比研究,针对"正等距+负移距"组合修形方式确定了优先选用的优化算法;对采用"负等距+正移距"组合修形方式,提出了一种改进的优化算法,将该算法与现有的优化算法进行对比分析,根据实际的装配精度确定了应优先选择的优化算法。     

RV减速器摆线轮拓扑修形齿廓研究

为使摆线轮具有良好的啮合性能,根据计算的摆线轮实际工作范围,将摆线轮齿廓分为工作段和非工作段齿廓,采用拓扑修形方法来满足工作段和非工作段的间隙要求。工作段采用转角修形,使修形后工作段为共轭齿廓,并保持一定的齿侧间隙。非工作段采用变等距修形,使齿顶与齿根部分产生合理的间隙,得到合理的修形齿廓。推导了摆线轮拓扑修形齿面方程,可以通过调整修形参数获得满足工作要求的齿廓间隙。从初始啮合间隙、载荷分布、回差分析方面验证了拓扑修形的合理性。     

摆线齿插齿加工刀具刃形设计

摆线轮是RV减速器中的关键零部件,其设计制造水平对RV减速器的传动性能影响巨大。现阶段,摆线轮制造能力难以适应RV减速器大批量生产的需要。为了提高摆线轮的加工效率,提出采用插齿加工方法加工摆线轮。依据插齿加工运动,建立切削刃设计计算坐标系。基于修形后的摆线轮齿形方程,推导插齿刀理论刃形方程。以某型号RV减速器中的摆线轮参数为例,进行插齿刀理论刃形设计。计算结果表明,设计的插齿刀刃形能与摆线轮齿形时刻处于"点接触"状态,证明提出的插齿刀刃形设计方法是可行的。进而提出了插齿刀前、后刀面的设计方法。最后通过切削仿真证明提出的摆线轮插齿刀刃形设计方法是正确的。     

RV减速器摆线轮齿廓修形对温度的影响

为分析摆线轮啮合过程中的温度特性,研究不同修形方式对摆线轮温度的影响规律,考虑摆线齿轮常用的3种组合修形方式,以相同的径向间隙为前提,对比分析摆线轮修形前后的接触应力与摩擦热量在轮齿上的分布情况。利用有限元分析,计算出修形前后温度场中的温度分布情况。结果表明：对摆线齿轮进行齿廓修形可以有效降低齿轮的稳态温度,组合修形中降温效果最佳的修形方式为正等距+正移距修形;单齿上温度梯度的密集程度随着啮合范围的减小而增大;摆线轮修形前后瞬时摩擦热量的最大值不受影响,峰值所处的位置会发生变化,而周期摩擦热量的峰值位于轮齿的同一啮合相位角上,但数值会随着轮齿受到的压力的增大而增大。     

RV减速器摆线针轮的有限元接触分析

基于有限元分析方法,研究加载状况下摆线针轮啮合副初始啮合时齿廓对的接触状态。考虑摆线针轮啮合副的齿廓修形和摆线轮齿廓线的建模精度,利用ANSYS自带的APDL语言建立了摆线针轮啮合副的三维模型。考虑有限元网格质量及有限元模型的计算效率,利用VSWEEP命令生成了有限元模型并局部细化了网格。最后考虑摆线针轮的实际工况,建立了摆线针轮的接触对和边界条件。分析结果表明:摆线针轮初始啮合瞬间一共有6个齿参与传力,其中最先接触齿为第6齿,并且在啮合齿廓对附近摆线轮齿及销孔变形比较大。     

可靠度约束下摆线针轮减速器加工精度优化北大核心

摆线针轮减速器主要用于高精密传动场合,其在加工过程中,会产生影响传动精度的制造误差。为在实际加工中选取符合传动条件的最优加工参数,基于坐标变换与齿轮共轭接触原理,建立了考虑齿廓修形、制造误差的轮齿接触分析模型,分析了不同种类制造误差对传动误差的灵敏度,并设计一种基于传动可靠度的轮齿修形参数与加工精度优化方法。结果表明,基于DIRECT算法对样本的最佳化计算,可得到一组在许用传动误差条件下制造成本最低的减速器加工参数,且该组加工参数具有高可靠度特性。因此该方法可为制造高可靠度摆线针轮减速机提供理论优化参考。     

传动比波动幅度约束下的摆线轮齿廓修形量优化

摆线轮齿廓修形对摆线针轮传动机构的承载能力和运行平稳性有重要影响。为获取最优的修形策略和修形量，提出了一种以最小化传动比波动幅度为优化目标、基于内点法的摆线轮齿廓等距-移距复合修形量的优化方法。以单级摆线针轮减速器为例，建立考虑修形后的摆线轮受力平衡方程，以及摆线轮针齿的轮齿接触方程，并通过优化流程将力平衡方程和轮齿接触方程耦合集成，从而实现对3种等距-移距修形组合策略下的修形量进行优化计算，发现正等距加正移距组合修形下的最优修形量可将传动比波动幅度降低40%,最大针齿接触力降低17%,实现更平稳的传动和更好的承载性能，也有利于提高减速器传动精度和寿命。     

RV减速器摆线轮齿形的研究

通过运用三坐标测量机对RV-40E型速器摆线轮进行精密测量,得到摆线轮齿形坐标参数,对所得参数采用最小二乘法进行圆弧拟合,结合所得摆线轮齿形与摆线轮齿形计算方程得到的齿形,与经过精密测量的摆线轮实际齿形进行对比,分析圆弧拟合与齿形计算方程两种方法得到的齿形形貌特征。并通过试制摆线轮来验证其工作寿命及精度。结果表明:该摆线轮的工作寿命及精度均达标,且方程计算齿形更具有实用性。     

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.     

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。     

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.     

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.     

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.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.