用数控技术改造平面磨床实现大曲面加工

在M7130平面磨床上加工一些特殊的零件,如加工圆弧半径为45m,弦长1m、表面粗糙度要求很高的曲面零件时,一般须采用多种工装,但效果都不能满足技术要求,因此对该磨床进行了数控技术改造。     

用图解法绘制圆球面与回转二次曲面的交线

圆球面与回转二次曲面的交线投影于其公共对称面上,可得一条抛物线。本文用解析法研究了该抛物线的基本参数,得到解基本参数的图解法,从而可精确地确定交线。     

由三维模型到二维投影

利用AutoCAD的三维模型,在AutoCAD的图纸布局中设置浮动视口,将三维模型向不同的投影面进行投影,然后使用Solprof,Solview,Soldraw命令提取三维模型的投影轮廓线并做适当的编辑操作,可以生成三维模型的二维投影图———视图与剖视图。用这种方法获得的二维投影图与三维模型之间存在着内在的联系,所以投影正确,避免了直接作二维投影图时容易产生多余或遗漏图线的现象,具有作图效率高、不易产生投影错误的优点。     

数控加工圆球工件浅析

日常加工生产中,刀尖圆弧会使加工工件产生过切或欠切现象,在进行圆球加工时影响尤为严重,刀尖半径自动补偿功能,可以有效解决这一问题,在刀具接触工件之前,自动进行圆弧插补计算,有效解决刀尖圆弧对加工的影响。采用同一刀具加工圆球工件到成品尺寸,使工件在加工精度和表面粗糙度方面都有显著提高。刀尖圆弧补偿参数的选用,对加工精度和表面粗糙度影响很大。     

用外摆线机构加工大半径圆弧曲面

加工连铸机结晶方形铜管内腔的芯子时,遇到加工半径为5.25m的圆弧曲面,如果按通常的机加工办法,所需要的专用设备的尺寸实在太大了。能不能用别的方法来完成这一曲面的加工,从而尽可能地缩小加工设备的尺寸降低加工成本,增加经济效益,这是我们要探讨的问题。 以90×90方长度为700mm的结晶器的芯子为例,其圆弧曲面的曲率半径为5250mm,由于它并不是一个完整的圆,而仅是圆的一部分,其整个长200mm(弦长)所对应圆的圆心角仅为3.8226°×2。经分析发现,圆的内摆线如果取其一段,只要诸参数选择得适当,完全可以代替圆,使其诸点与圆的诸点对应误差在限定     

大尺寸圆弧划线法

我公司在制作铁水包和渣包等自用圆台形产品时发现,它们的母线与中垂线的夹角一般都在5°以内,桶体的平面展开半径通常在20m左右(最大的达到32m)。这种扇形样板的传统划线方法有两种:一是坐标法,需通过大量的等分计算,在样板上逐一找出各等分点的相应坐标,费时费力。二是实划法,即用一根与圆弧展开半径相等的细钢丝,一端定位后为圆心,另一端在样板上直接划线。这种方法简单,但要求有足够大的划     

用Y54插齿机加工摆线泵内转子

我厂修机车间大修 Z35摇臂钻床中发现润滑用摆线油泵打不上油.原因是内转子(图1a)和外转子(图1b)磨损而使间隙过大(近0.7mm).其中内转子磨损较严重。由于该转子顶圆仅φ20mm,且磨损处在齿顶,采用补悍等修理方法困难较大。故需新制内转子。摆线油泵内、外转子主要参数为:内外转子偏心α=2内转子齿数 Z_1=4外转子齿数 Z(?)5外转子圆弧齿形半径 R=100外转子内接圆半径 r(?)=8.25范成半径 R_1=R+r(?)。=10+8.25=18.25内转子顶圆半径 r_(?)=r_(a2)+a-8.25+2=10.25内转子根圆半径 r_(?)=r_(a2)-a-8.25-2=6.25这种油泵的外转子齿廓曲线是圆弧.内转子是该圆弧齿形的共轭曲线——短辐外摆线的等距曲线     

金属切削机床精度检验通则(十)(JB2670—82)

5.5.1.2.5 一轴线对两平面交线的垂直度 5.5.1.2.5.1 固定轴线 将具有相应基座的角尺贴靠在代表轴线的圆柱面上(见图47)。用有     

关于一种测量高压电缆转弯半径专用尺的研发应用

<正>电缆安全运行的关键因素是其绝缘的良好程度和内部电场分布的均匀性。电缆弯曲半径是电缆敷设施工及运行中保证其绝缘性能的主要指标。所谓弯曲半径,是指工程上把弯曲的电缆近似看做一段圆弧,圆弧所在圆的半径即为此弯曲电缆的弯曲半径。电缆敷设过程中经常遇到转弯半径不足的情况,验收人员由于没有相应仪器设备测量,凭工作经验判断半径是否满足运行规程,得出模棱两可的答案。转弯半径不足将对日后运维埋下安全隐患。为了解决上述问题,     

滑梯式曲线隧道空间测量技术

一、工程概况某隧道在主坑道左上方设一通风口,设计断面为直墙圆拱形,净空8×6m,通风口曲线半径R=63m,倾角α=22°,初期支护喷混凝土20cm,衬砌等厚,有0.5m、1.0m、1.5m三种类型(见图1、2)。由于平面旋转,纵向上升,在空间位置上类似于滑梯。此类滑梯式曲线隧道,由于特点突出,所以,测量方法上与一般隧道显著不同。下面从水平投影、铅垂投影两方面来阐述曲线的空间关系。二、水平面投影位置的确定1.建立测量直角坐标系。以圆心与起点连线为y轴,以起点切线方向为x轴建立测量坐标系(见图1),标,公式见下:Mx=x+Bsin(2 )(4)My=y+Bcos(2 )(5)B…     

桂林电厂以大代小技改工程圆形双曲线金属小煤斗设计

在桂林电厂以大代小技改工程原煤管道设计中 ,采用了圆形双曲线金属小煤斗 ,有效解决了原煤堵塞问题 ,本文介绍圆形双曲线金属小煤斗的设计计算方法     

Experimental Research on the Relations between Stereoscopic Vision and Mechanical Designers' Activities, with a View to C.A.D. Teaching

This study examines the influence of two crossed factors upon the performance of a subject whose aim is to understand the functioning of a complex piece of technical apparatus, in this instance an automated arm from an assembly line. The primary factor was the encoding degree of the third dimension which constitutes the representation of the object. The methods of presentation were: a 3-D photograph, an axonometric perspective drawing and a first angle orthographic drawing. The second factor was professional experience. The subjects were, on the one hand, first year technology pupils (15--16 year-olds) and, on the other hand, professional draughtsmen from RENAULT. The results obtained with the 3-D photograph were twice as good as those obtained with the axonometric perspective or the orthographic drawing. It should be pointed out that experience did not effect the score. This revised version was published online in July 2006 with corrections to the Cover Date.     

椭圆上特殊点的准确作图原理简析

画法几何中用八点法作椭圆时,一般是根据圆的外切四边形画出平行四边形,从而确定两对特殊的共轭直径,所画椭圆的8个特殊点中总有4个点可以比较直观地确定,而其余4个点只能近似地在相应的共轭直径上求出。本文应用仿射对应等方法,阐述了准确定出椭圆周必定经过的特殊点的位置,并提出其作图的理论根据,同时提供了多种准确快速地确定这些特殊点的方法。     

The Early Mobilization of Women Union Leaders — A Comparative Perspective

This article explores the initial reasons for union joining of women who became union leaders in the UK and the USA by drawing on concepts from mobilization theory and the literature on women and unions. The comparative study demonstrates similarities and differences in early mobilization influences on UK and US women with respect to family, ideology, instrumentality and injustice. Informed by the women and unions literature, the article critiques mobilization theorists for failing to problematize the term ‘injustice’ and underplaying the importance of ideology which are shown to be gendered and racialized and located in time and place.     

沥青混合料路面早期裂缝的成因及其控制

沥青混合料面受多种因素的影响，早期产生不规则裂缝是当前普遍存在的现象。根据对基层、温差、预留孔洞、沥青混合料质量等原因的分析，提出了加强沥青路面的多方面综合控制的措施。     

Risks,possibilities, and social relations in the computerisation of Swedish university administration

This mixed methods case study discusses how the introduction of new technology changed the work of departmental administrators at a Swedish university, drawing on Cockburn's theories on gender and technology, viewing organisations as fields of contestation. This paper argues that jobs seem more fragmented with less discretion, as a result of computerisation. However, time saved by a new division of labour enabled by digitalisation has increased the possibilities for specialisation and job crafting. This new division of labour also led to increased tensions between academics, administrators and management. As the risks and possibilities connected to computerisation are matters of social relations, as much as being governed by technology, this paper adds to the debates on work and technology by exploring the complexity of social relations at work place level experienced by this overlooked group at the periphery of the managerial and academic power centres in academia.     

基于结构平衡原理的服装工业推板

本文从如何推出具有平衡效果的结构图入手,深刻剖析影响推板的两个因素,即不能完全遵循纯数学的原理和制板公式。本文从结构平衡的角度出发力求探讨一种最简便、最快捷的推板方法,能够保持款式的稳定性。     

Drawing Out Ideas: Graphicacy and Young Children

Drawing offers a powerful mode for representing and clarifying one‘s own thinking and for communicating ideas to others. Young children instinctively use drawing in the same exploratory way that designers use sketching to ’converse with themselves‘ when generating ideas. The two distinctive traditions of drawing in Technology and Fine Art are replicated in the Design and Technology and Art and Design curricula in England and Wales. However, because we lack research evidence about (i) the processes by which children develop drawing capability and (ii) the effects of school culture and pedagogy on the development of children‘s drawing capability, teachers are confused about how to teach drawing and unsure about the role of graphicacy in promoting children‘s learning in both subjects. In this article the particular dilemmas of teaching design drawing to young children will be discussed. A research agenda for the teaching and learning of drawing in primary schools will be outlined. This revised version was published online in August 2006 with corrections to the Cover Date.     

Images of the Virtuous Employee in China's Transitional Economy

We examine contemporary images of employee virtue and managers' perceptions of actual employee conduct in Wuhan, Beijing and Xi'an, drawing on document analysis and structured interviews with 112 respondents in ten case study companies. The image promulgation strategies of the one joint venture enterprise and the two private enterprises in our sample entailed active avowal of tradition linked employee virtue, drawing on a mixture of Communist and Confucian moral imagery. In contrast, most of the seven state-owned or predominantly state invested enterprises had abandoned or marginalized traditional Communist imagery, none promoted Confucian imagery, and two emphasized alternative images of one-sided servility toward the customer. We infer, from managers' accounts, that the abandonment of tradition linked images by the state-owned sector was a tacit acknowledgment of prior covenant violation, and that outside the state-owned sector, tradition linked moral propaganda contributed to moral atmosphere only when part of a consistent high-commitment HRM strategy. In drawing out implications for theory and further research, we note the different socio-political contexts of organizations in China and the West, discuss the relationship between bonds or covenants and psychological contracts, and compare tradition linked employee virtues with dimensions of organizational citizenship.