变位齿轮及其测绘方法

在实际生产中使用变位齿轮,可以弥补标准齿轮传动中的以下缺陷:(1)齿轮副的小齿轮齿根薄,两轮材料相同时小齿轮强度弱。(2)小齿轮齿根滑动和几何压力系数均比大齿轮高,所以小齿轮易损坏。(3)标准齿轮不适于中心距≠α的场合(α——标准中心距,α′——     

切向变位齿轮及其加工

制造和维修零齿差齿轮付时,都会遇到切向变位齿轮的加工问题。本文就齿轮切向变位的概念和在滚齿机、揷齿机上加工切向变位齿轮的方法作一介绍,以供参考。一、齿轮切向变位的概念零齿差少齿差减速器结构简单,制造也不困难,所以在小功率轻载的机械设备减速机构中常被采用。零齿差机构是用来传递轴间距较小的两平行轴之间的     

关于变位齿轮变位系数优化设计

在进行变位齿轮设计的过程中,合理选择变位系数是设计变位齿轮的关健环节。本文论述了利用电子计算机对直齿外接圆柱齿轮的变位系数进行优化设计,以及计算最佳变位系数状态下的中心距、重合度系数、齿顶圆直径、基圆直径和公法线长度的方法。一、齿轮变位方式     

变位齿轮变位系数的选择

目前关于变位系数ξ_1和ξ_2的选择方法很多,常见的有查表法、线图法及封闭图法。一般认为封闭图法较完善,可惜它只提供一定的选择范围,而对每个ξ_1、ξ_2点缺乏具体的传动质量数值。本文尝试用迭代法计算,为满足某项主要传动质量指标而直接算出变位系数。即采用季克尔的建议,考虑齿轮副的重合系数ε、滑动系数η、比压系数ζ等传动质量指标。本文计算是以压力角α_0=20°、齿顶高系数f=1的外啮合圆柱齿轮为例,对其他压力角和齿顶高系数也适用。一、选择原则和限制条件齿轮的破坏形式与其工作条件密切相关。工作条件有开式和闭式传动、高低速度、轻重载荷、高低精     

圆柱变位齿轮的非变位处理

一、问题的提出 如果要加工数量不多,且种类繁多的齿轮,用线切割方法较为合理,省去了制造刀具的时间和费用。但在老的     

计算机辅助设计变位系数封闭图及其应用

分析了各种变位系数选取方法及变位系数封闭图的数学模型,用计算机辅助实时设计变位系数封闭图,在封闭图中选取变位系数时动态设计,显示齿轮强度等多项与传动质量指标相关数据,并通过计算实例与传统设计方法进行了比较。     

常用焊接变位机种类及其选用原则

推土机、挖掘机、压路机等工程机械关键结构件焊缝复杂,焊接难度较高。     

大变位齿轮变位系数的可视化设计

介绍了大变位齿轮的特点，变位系数的设计准则。采用计算机可视化方法设计大变位齿轮变位系数，此方法实用、可靠，适合工程应用。     

利用齿轮变位原理求解单个齿轮变位系数

文中简单介绍了齿轮变位的原理,阐述了怎样利用齿轮变位原理来求解单个齿轮的变位系数。     

Hybrid treatment by a laser beam and surface plastic deformation

The formation of multilayer oriented microstructure and surface roughness under the action of continuous laser radiation and surface plastic deformation is considered.     

Surface plastic deformation of threads in ultrasound treatment

By the analysis of plastic deformation with ultrasound treatment, analytical formulas are obtained for the strain rate and stress rate and the deformation of the thread profile is estimated. The use of ultrasound treatment to correct the geometric parameters of the thread and strengthen its surface is considered. The effectiveness of ultrasound treatment of threads is confirmed.     

轴承套圈热处理锥度变形的分析及控制

针对轴承套圈淬火锥度变形较大的问题,探讨了轴承套圈锥度变形的产生机理,认为网带炉有控制轴承套圈锥度变形的优点。通过对网带炉油槽小网带的线速度改变对比试验,得出18s翻转时间能较好的控制6210外套的锥度变形,同时认为网带炉并不能完全保证设备加工范围内轴承套圈的有序翻转,从而导致部分套圈锥度变形值较大。     

奶牛乳房炎病的诊治

奶牛乳房炎是奶牛养殖过程中的常见病之一,可导致产奶量下降、奶质量不合格和全身感染。预防本病需要加强管理和规范挤奶操作;抗生素是治疗本病最有效的药物,但需要考虑药物残留和乳汁食品安全问题;轻度乳房炎可用中药和物理疗法进行治疗。     

Mechanical properties of tungsten wires after cycling deformation treatment

This article presents the influence of cycling deformation treatment executed by continuous multilateral bending with shearing on the mechanical and technological important properties of tungsten wire intended for production of spiral shapes. The mechanical properties are determined by a simple uniaxial tensile test while the technological capability is based on torsion with tension test (TT test). It is shown that the cycling deformation treatment of the wire practically does not change its mechanical parameters, but significantly increases its technological properties. The results therefore indicate an inadequacy of a simple tension test for selection (quality assessment) of tungsten wires.     

减少轴承套圈热处理变形的方法

针对中、轻系列轴承套圈在滚棒炉加工变形较大的问题,将热处理工艺参数进行调整,较好地解决了该问题,减少了浪费,保证了产品质量。     

Large deformation compression–torsion behaviour of a titanium alloy and its modelling

A range of sequential and compound compression-torsion tests has been carried out on titanium alloy IMI834 at 1000°C and nominal true strain rate 5 × 10⁻³ s⁻¹, typical of forging conditions. The tests were used to investigate initial and subsequent yield and flow behaviour, the nature of the material hardening and the effect of flow softening on subsequent deformation. In addition, a material model with isotropic or directional hardening has been used to predict the material behaviour.The results show that the material behaviour at large strains is reasonably isotropic, although a directional hardening model provides slightly better quantitative agreement with the experimental results. Large pre-strains (0.4), either axial or torsional, are found not to change significantly subsequent material behaviour. A stress state dependence of flow softening is observed to exist.The material model presented is shown to give good quantitative agreement of predicted and experimental results.     

Oxide scale characterization of ferritic stainless steel and its deformation and friction in hot rolling

The oxidation kinetics of ferritic stainless steel 430 was studied in dry and humid air at 1090 °C by Thermo Gravimetric Analysis (TGA). Different atmospheres and heating times were adopted for reheating to obtain different compositions and thickness of the oxide scale. Hot rolling was performed on a 2-high Hille 100 experimental rolling mill at various reductions. Oxide scale thickness and composition were analysed with optical microscopy (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The surface profiles were examined by a digital microscope, and the topographic features of the thin oxide scale surface were examined with an atomic force microscope (AFM) before and after rolling. The oxide scale surface and steel/oxide interface roughness were measured after rolling. Inverse calculation of the coefficient of friction was employed to analyse and the effect of oxide scale on friction in hot rolling. The coefficient of friction depends not only on the thickness of the oxide scale, but also on its composition and surface topography before hot rolling.     

Geometrical nonlinear deformation model and its experimental study on bimorph giant magnetostrictive thin film

The geometrical nonlinearity of a giant magnetostrictive thin film (GMF) can be clearly detected under the magnetostriction effect. Thus, using geometrical linear elastic theory to describe the strain, stress, and constitutive relationship of GMF is inaccurate. According to nonlinear elastic theory, a nonlinear deformation model of the bimorph GMF is established based on assumptions that the magnetostriction effect is equivalent to the effect of body force loaded on theGMF.With Taylor seriesmethod, the numerical solution is deduced. Experiments on TbDyFe/Polyimide (PI)/SmFe and TbDyFe/Cu/SmFe are then conducted to verify the proposed model, respectively. Results indicate that the nonlinear deflection curve model is in good conformity with the experimental data. __________ Translated from Journal of Dalian University of Technology, 2007, 47(1): 34–38 [译自: 大连理工大学学报]     

数控机床热误差的智能补偿方式及应用

热变形误差是影响数控机床加工精度的重要因素之一,因此减少热变形误差对提高数控机床的加工精度至关重要.以HMC800A立式三轴数控加工中心为对象介绍了热变形误差的测量方法,采用粗集理论的属性简化来建立测温点和热变形误差之间的相关程度从而优化测温点,使输入数据更具合理.运用BP神经网络理论建立了机床热变形误差和温升之间的数学模型,进行研究分析.最后通过MATLAB仿真实验结果表明了补偿效果的可行性.