等高齿弧齿锥齿轮的三维精确建模与加工试验

基于格里森制弧齿锥齿轮,运用局部综合法与轮齿接触分析(TCA)技术,研究等高齿弧齿锥齿轮的几何设计、加工参数设计和刀盘参数。通过UG软件,建立该齿轮的三维精确模型,对大、小轮模型进行运动仿真,模拟齿面的接触区情况。该等高齿设计的弧齿锥齿轮,在加工时只需采用0号刀盘,简化了选刀过程,避免了对角接触。此外,该等高齿设计的弧齿锥齿轮能够进行磨齿加工。在GH35铣齿机上进行铣齿试验,试验结果表明:该等高齿接触区规范,易于调整,提高了加工效率。     

圆弧等高齿弧齿锥齿轮的设计与性能分析

为了改善齿轮副的对角接触现象,将常规弧齿锥齿轮的渐缩齿改为等高齿齿形,采用0号刀齿铣齿,从理论上避免对角接触。基于齿轮的局部啮合原理、齿面接触分析(TCA)技术和承载齿面接触分析(LTCA)技术,对相同条件下等高齿设计与常规齿轮设计的实际接触区、载荷及应力应变进行了分析。分析与加工试验结果表明:理论与实际接触区位置基本相同,所受力的大小以及应力分布也基本相同。与传统的齿轮设计相比,等高齿弧齿锥齿轮设计保证了齿轮强度、齿轮啮合质量,使其接触区规范且易于调整,有利于提高加工效率。     

双圆弧弧齿锥齿轮啮合分析

本文从弧齿锥齿轮加工原理出发,阐述了分阶式双圆弧等高齿弧齿锥齿轮副共轭齿面的形成原理,推导了该种齿形锥齿轮的啮合方程、接触线方程、啮合面方程以及具有通用形式的齿面方程,并分析了产形轮齿面曲率分布状况。     

数控多功能任意齿形锥齿轮加工装备及技术

该技术可用于加工任意设计齿形的直齿锥齿和多种齿制的螺旋锥齿轮数控加工装备和相关软件系统。可以根据使用要求开发多功能锥齿轮加工机床或专用锥齿轮加工机床。     

减小螺旋锥齿轮齿面加工误差的参数修正方法

针对螺旋锥齿轮加工过程中因无法避免误差而导致齿面加工精度难以保证的问题，提出螺旋锥齿轮加工误差控制模型及加工参数修正方法。首先，基于实际加工中的刀具与工件相对位置与相对运动关系，依据坐标齐次变换与啮合原理，确定加工参数与加工曲面之间的函数关系，建立螺旋锥齿轮精确齿面模型；然后，计算实际加工齿面与理论齿面的法向距离，从而建立由加工参数驱动的齿面几何误差控制模型；接着，对加工参数进行敏感性分析，选取敏感性较高的加工参数作为误差补偿模型优化变量，以提高优化效率；最后，将齿面误差最小化问题转化为最小二乘法问题，基于改进的L-M算法进行求解，得到加工参数补偿量，以此对加工参数进行修正达到减小齿面加工误差的目的。采用一对由双重螺旋法磨削加工得到的螺旋锥齿轮副作为应用实例，对该方法进行实际加工验证，结果表明：加工参数调整后，螺旋锥齿轮齿面加工误差降低了65%以上，实际测量的齿面绝对误差均不超过0.005 mm,能够满足工程实际需求，证明该方法能够有效提升齿面加工精度。该方法可为螺旋锥齿轮乃至其他复杂曲面零件加工提供一种加工误差补偿思路。     

大重合度锥齿轮的优化设计

本文提出了重合度大于2的直齿锥齿轮和小螺旋角弧齿锥齿轮的优化设计方法。这种大重合度锥齿轮采用了长齿高制(h*>1)和负传动设计,可在现有的机床上使用标准系列刀具加工。     

双圆弧弧齿锥齿轮制造工艺和试验研究

本文阐述了切削刃为分阶式双圆弧齿形的双面精切刀盘设计与制造工艺,重点叙述了打磨砂轮及铲磨刀齿的工艺过程。用同一双面刀盘在格里生机床上成功地切出了等高齿双圆弧弧齿锥齿轮副。台架试验表明了双圆弧弧齿锥齿轮不仅有良好的接触区,而且综合强度也有明显的提高,从而为使用此种新型锥齿轮从工艺和性能上提供了可靠依据。     

等距曲面理论及其在螺旋锥齿轮齿面误差检测中的应用

齿面加工误差检测是螺旋锥齿轮制造过程中的关键环节。针对螺旋锥齿轮齿面难以检测的问题,分析了等距曲面理论及其在齿面检测数据处理过程中的应用方法。基于等距曲面理论,确定了齿轮测量中心的理论运动轨迹,获取了实际加工齿面的真实误差,同时,也为一维测头在锥齿轮检测中的推广应用提供了支持。     

弧齿锥齿轮螺旋变性展成法及其轮齿接触分析

提出了一种新型螺旋锥齿轮加工方法——螺旋变性展成法.该方法大轮采用展成法加工,小轮采用螺旋变性法加工.分析并归纳了传统展成法中对角线接触现象的成因,建立了螺旋变性展成法刀盘压力角求解的几何模型,阐释了螺旋变性展成法消除对角线接触的原理.结合机床运动,分析螺旋变性展成法加工弧齿锥齿轮的齿面展成过程.依据齿轮啮合原理,获得小轮和大轮的齿面方程,据此模型开展轮齿接触分析,并与传统展成法作了对比分析.最后根据该方法以弧齿锥齿轮副进行啮合仿真和切齿试验,仿真结果及滚检试验结果表明,采用螺旋变性展成法加工螺旋锥齿轮副可从理论上消除接触区呈对角线接触的现象,能有效改善齿面接触质量.     

螺旋锥齿轮空间曲面NC加工插补误差分析

基于空间曲面共轭原理，建立螺旋锥齿轮的齿面矢量方程，由空间坐标系的变换，确定出刀具相对工件的位置和姿态，实现刀具与工件的相对运动，在综合考虑齿面形状、刀具形态及机床结构等因素的基础上，分析了五坐标螺旋锥齿轮面NC过程插补误差，建立考虑齿面NC插补误差的螺旋齿轮数控加工方法，计算结果与加工实验结果基本一致。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of