皮带轮和电机轴配合的基本知识

在电机修理中,拆卸皮带轮有时很费力,不得已时须借助油压机等设备或工具。装配太紧时拆卸易把皮带轮轮边部分拉破,甚至使皮带轮断裂,这主要是皮带轮和电机轴配合间隙不当所致。例如修配制作皮带轮时,尽管给出加工公差尺寸,但车工怕出废品,在车轴时宁大勿小(取上限),而车皮带轮内孔时宁小勿大(取下限),所以就会出现偏紧的现象;还有键的配合不当也是造成过紧的原因。皮带轮孔和轴的配合是H7/k6或K7/h6,属于过渡配合,装配方法为手锤轻轻打入即可。皮带轮的键联接,多数属于较松键联接和一般键联接,它们的公差配合是在间隙配合到过渡配合之间(附表)。通常键与轴槽配合     

喷熔法修复摩擦压力机主螺杆

摩擦压力机的主螺杆和飞轮之间用强力切向键联接.由于使用日久或更换键时装配不当,主螺杆及飞轮上的键槽容易损坏.如不很严重时尚可用另配键等简单方法解决;但当键槽严重损坏时,一般简单的修理方法就无能为力了.更换主螺杆及飞轮效果虽好但费用大,且仅因键槽损坏就废弃亦不合理.为此,经过研究比较,我们采取主螺杆用氧乙炔焰粉     

楔键拆卸一法

机床设备的驱动齿轮,有时用普通楔键与传动轴联接。在有些检修项目中,需要拆卸齿轮时,必须先拆卸楔键。在楔键的外伸大端有-M16的螺孔,供拆卸用。但有些楔键楔入太紧,将M16螺杆拉断了还是拆不下来。现以我厂ψ560×510×1530橡胶开炼机齿轮的楔键为例,介绍一     

一种过盈配合拆卸在轴上的应用

在传统设备安装和维修中对轴和轴承,轴和齿轮,轴和轴套联接分析对比,采用静压油膜拆卸方便快捷,对轴也进行有效保护,省去轴和轴套、轴和齿轮键联接加工制造工艺,避免对联接部位的拆卸相互损伤,适应机械领域的发展和应用。     

轮与轴双锥套无键联接应用初探

选矿厂4’×7’(φ1220mm×2135mm)球磨机中,传动轴与小齿轮采用φ115(H7/K6)配合加平键联接。其配合长度为310mm。这种常规联接形式结构虽然简单,但运转中键槽易被压溃,轴向定位不便,拆卸困难。经过反复研究和计算,将键联接结构改为锥套无键联接。改进后的结构如图1所示。传动小齿轮与轴采用双锥套无键联接,其锥度为1:30,配合长度为200mm。在锥套上沿轴向开设单锯缝,外锥套一端设有法兰,并设拆卸螺孔和压装螺钉孔,通过压装螺钉,把外锥套推向右边,此时内锥套的外径胀大,外锥套的内径缩小,从而     

失效键联接的修理

键联接广泛用于传递轴，毂零件之间的扭矩。当键槽被压溃后，在错开90°180°等位置重新加工的     

汽轮机叶轮键槽裂纹的焊接修复

汽轮机叶轮的材料大都是34CrNi3Mo,叶轮与轴的联接是键联接,叶轮键槽底部转角处常有裂纹产生,因裂纹造成叶轮飞裂者时有发生。我们选择了挖修裂纹焊补法,并对叶轮键槽的焊接性能和焊补工艺作了分析和研究。 一、叶轮键槽焊接性能分析 根据国际焊接学会规定的碳当量公式来估算可焊性,34CrNi3Mo的碳当量为1.05％,当钢的碳当量超过     

圆锥体联接国家标准的应用

介绍了国家圆锥体联接系列标准的主要内容和石油机械圆锥体联接标准化情况。     

F320-3DH钻机摩擦鼓的改制修复

F320-3DH钻机是70年代中后期从罗马尼亚进口的6000m大型石油钻机,大量使用了气胎式离合器。常因摩擦鼓与摩擦片的频繁摩擦,产生过热而导致摩擦鼓钢圈发生裂纹,严重时裂纹布满整个表面,有的裂纹穿透钢圈,有的甚至穿透至法兰联接筋板,造成摩擦鼓报废。摩擦鼓有几种不同规格,因装配位置不同,其内部筋板的联接结构方式也各不相同,互换性差或根     

键条式气胀轴维修实例

彩报印刷机使用的零速自动接纸机键条式气胀轴漏气维修实例.给出气胀轴内部结构图及气胀轴的拆卸和装配过程.     

免棱镜全站仪在已有建筑测绘中的应用方法

结合实际测绘情况,介绍了利用免棱镜全站仪的数据采集功能进行外业接坐标、现场人工绘草图、内业数据处理后在AutoCAD中展点成图,在此基础上结合钢尺测量数据,绘制平、立面图的方法,并对该测量方法的实施步骤和关键技术作了较为详细的介绍。     

Gravitating toward the quadruple helix: international connections for the enhancement of a regional innovation system in Northeast Italy

The majority of previous Regional Innovation System (RIS) studies generally provide a rather static overview of the roles of innovation-creating actors. This article explores a single RIS in Trentino in Italy. The case shows that the roles of three actors (i.e., the provincial government, academia/research centers, and firms) are vital in creating the RIS, and that the provincial-level government policy is important in supporting the innovation activities of regional research institutions and firms aimed at developing their international connections. The public-private research collaboration and international connections of these actors are the key determinants of the development of an advanced RIS, but have largely been ignored in the extant RIS literature. This article extends the existing RIS and Triple Helix research to an international dimension, highlighting the complementary role of international connections within the RIS, thus reflecting a shift toward Quadruple Helix.     

浅谈工程项目投资的全过程控制

章简述了工程项目投资全过程控制的原理，以及各阶段对工程项目投资控制所起的作用和控制的方法。在工程建设中投资控制应注意抓住投资决策控制和设计控制，它们是工程项目投资的全过程控制的关键性环节。     

浅议项目评价中基准贴现率的确定

介绍了两种确定基准贴现率的方法-最低期望收益率和目标收益率法，并结合实例进行了说明：前者是一种偏低的标准；后者比较符合实际标准，但需要较好的基础工作。     

Connecting IMP and entrepreneurship research: Directions for future research

As a research field, entrepreneurship emerged from an increasing interest in fostering new business ventures. Over the past decade, interest in entrepreneurial phenomena also triggered several studies in the IMP research stream. We examine connections between these two research streams in terms of the phenomena in focus, key concepts, and approaches to identify research areas fruitful for advancing our understanding of entrepreneurial phenomena. In pursuit of this aim, we analyzed 48 IMP-based entrepreneurship studies and the abstracts of the 227 most cited papers in eight main entrepreneurship journals; among the latter, we conducted an in-depth analysis of 30 articles, in which we found connections with IMP studies. Based on our analysis, we identify four directions for future research, where confronting and bridging the key concepts has the potential to contribute to conceptualizing entrepreneurial phenomena and related theory development. The four areas are: variety in the context of new ventures; multiplicity of networks embedding new ventures; connecting the new venture to its context; and the new venture's learning and management.     

Industrial relationships and the effects of different types of connections

Emphasizing the primary and secondary functions in business networks, this paper is based on the presumption that the primary function of the focal dyadic relationship is connected to business, political, ancillary and competitive relationships, i.e. what has been denoted as the secondary function. The question is how these secondary functions affect the primary function. The conceptual view developed for the focal dyadic relationship is founded on the two key relationship concepts of trust and commitment. The empirical study is based on a survey of 353 firms and their most important customer relationships. The analysis examines nine hypotheses through a structural model in LISREL. Conclusions from the statistical test show the heterogeneity in the impacts of these different types of connections on trust and commitment. Knowledge of the impact of these connections can aid the further understanding of relationship connections and also assist business firms in developing strategies towards these units.     

基于Solidworks & SimMechanics的机构运动分析与仿真

介绍了几种常用机构运动分析的方法及特点,重点阐述了以Solidworks和SimMechanics 为工具,通过机构的实体造型、建立机构模型、设置各模块参数及仿真参数等环节,对摆动导杆机构和曲柄摇块机构在给定驱动力下的运动性能进行分析与仿真,绘制了机构关键点的运动特性曲线,得到了机构运动的仿真动画。指出这种机构运动分析...     

广州新体育馆建设工程新技术新工艺的应用

广州新体育馆是为了迎接“九运会”在广州举行而建设的一座综合性多功能体育设施，是一个以体育比赛为主，兼顾艺表演、会议展览的多功能综合性体育建筑，也是广州市新世纪重点、标志性建筑。在该工程建设过程中，采用了许多国内外的新技术、新工艺、新材料，结合新的承包经营管理方式，使得项目在工期紧任务重的情况下圆满完成。章详细介绍了该工程土建、结构、设备等工程施工方面的难点及其新技术、新工艺和新材料的应用，这些在该项目的建设及竣工后的经营管理中都产生了良好的效果。     

六西格玛方法在油田修井作业的实践初探

结合油田修井行业特点和生产实际,在修井作业领域引入六西格玛理念和方法,运用六西格玛DMAIC改进流程来缩短作业周期。通过对影响作业周期的因素界定、测量,针对测量结果对根本性原因进行分析,对关键要因从管理上、技术上、标准化3个方面进行优化、改进和固化,从而缩短作业周期,实现了修井作业"精细、有序、经济"的高效运行目标,收到了良好的效果。     

煤炭企业管理创新与实践

介绍了煤炭企业应对宏观形势提升管理的重要性,并结合新矿集团华丰煤矿的实际情况,对实施管理提升工程进行了探讨。分析了企业围绕工作重点,进行了强管理、控成本、促销售的创新做法和成效,提出煤炭企业加强成本管控、拓展销售渠道和销售方式等管理创新提升的措施。