连杆轴瓦夹具的设计

连杆轴瓦内孔加工要确保很高的表面粗糙度、垂直度及同轴度公差要求,一般通用夹具难以保证其加工精度。本次设计的专用夹具是采用多头螺纹与锥度式紧固元件相结合,很好的解决了轴瓦内孔的加工问题。     

定位环零件切削加工工艺及夹具设计

1定位环零件图分析如图1所示为定位环零件图,该零件形状简单,材料为STKMl6A,综合切削性能较好。两端面的平行度公差及粗糙度可通过磨削加工即可保证;内孔尺寸及形位精度要求较高,通过数控车削加工,在适当的定位与夹紧方式下,可保证加工精度。     

对数螺旋齿轮精密加工工艺研究

针对对数螺旋齿轮精密成形工艺的特点,通过滚齿机、数控滚齿机范成精密加工方法,从而保证了精密加工要求,并运用专用工装设计的原理,介绍了几种对数螺旋齿轮精密加工的工艺措施,保证精密加工精度和任意螺旋角变化规律的要求．     

工件在圆孔中定位计算公式的分析

工件以外圆柱面作定位基准在圆孔中定位时,定位元件一般制成定位套装于夹具体中。由于外圆柱面定位在机械加工中所占比率很大,所以这种定位方法应用也较广泛。但目前教科书和设计手册中所使用的计算公式值得进一步分析,现讨论如下: 采用这种方法定位时,工件可能产生的定位误差是圆柱体中心线在径向的位移和倾斜。为了保证轴向定位精度,通常采用外圆柱面与轴肩端面联合定位。此时,如果以外圆柱而作为主要定位基面,限制工件四个自由度,轴肩端面只限制工件一个自由度。在这种情况下,工件轴肩端面与外圆中心线的不垂直,只引起轴向定位误差。不需对定位能否实现进行验算。但是,如果需要工件轴肩端面作为主要定位基面,限制工件三个自由度,而外圆只限制工件两个自由度时,就要求定位轴肩端面与定位元件有良好接触,以保证定位精度和定位稳定,提高定位刚度、避免加工振动。此时应该对工件轴肩端面能否与定位元件良好接触进行简单验算。目前教科书和设计手册中验算式     

基于双频激光干涉仪的精密定位系统设计

为实现某些光学部件或高精度测量仪器快速驱动与定位,设计并实现了一套快速精密定位系统。该精密定位系统采用双闭式气浮导轨支撑工作台,直流力矩电机通过谐波减速器减速,以摩擦驱动的方式实现快速定位。以双频激光干涉仪作为最终位置反馈,有效地在定位过程中消除了系统在运动过程中形变和应力释放带来的不确定干扰。采用带有前馈算法的PID控制技术,通过调节各参数,使系统具有快速平滑的响应特性。相对于传统设计方式,在保证精度的同时,降低了系统的复杂程度,也降低了对加工工艺的要求。经过实验测试,定位精度可达176nm,单步稳定所需时间在2 s以内,满足精密定位需求。     

浅议现代机械制造工艺与精密加工技术

机械技术是机电控制系统重要的基础技术,近年来,随着经济社会的不断发展,机械制造技术也取得了巨大的进步,传统的机械制造技术已经难以满足当前机械制造的需要,引进现代化的机械制造和精密加工技术成为机械制造与精密加工行业的迫切需求.本文主要从两个方面进行了探讨:一是现代机械制造工艺和精密加工技术的发展特点;二是对现代机械制造工艺和精密加工技术的探讨,希望能对业内人士有所帮助.     

关于发动机窜烧机油故障的分析与排除

本文主要介绍一台东风牌汽车发动机大修镶新丝套后,出现了窜油故障,但检测有关部件的密封配合,以及用量缸表测量气缸体圆度、圆柱度偏差,均符合技术要求.后经拆检分析发现,窜油故障是由气缸体承孔加工不符合标准要求,精度偏差超过极限所致.     

大缸径油缸内孔加工装备的技术研究

滚压加工是将硬度高且光滑的滚柱与金属表面滚压接触,使其局部产生微小塑性变形进行精加工的塑性加工之一。此系列推镗头、滚压头专用于大缸径油缸的内孔加工。利用推镗头先镗去油缸内孔的大部分加工余量,为精加工(滚压)提供合适的切削余量、粗糙度、内孔直线度和圆度,滚压头利用滚柱对油缸内孔表面施加一定压力,使金属产生塑性变形,从而达到加工要求的尺寸精度、粗糙度和形状公差,滚压加工可提高零件表面的硬度、耐磨性和疲劳强度。     

车床尾座主轴机械加工工艺过程简要分析

根据设备配件的制作的工作实践,对车床尾座主轴的机械加工工艺过程,从加工阶段的划分,定位基准的选择,工序的安排顺序等方面进行了简单的探讨与分析.     

BRW200/31.5乳化液泵滑块连接圆柱销挡块车胎的设计和日常维护

BRW200/31.5乳化液泵圆柱销是连接连接活塞杆于滑块的连接定位元件,为了不让圆柱销两端划伤活塞缸内壁,在圆柱销两端放置了材料为聚甲醛的两个挡块,挡块的圆弧面直径要于活塞缸内壁直径相同,并且还要有配合精度要求.为了保证配合精度设计了加工圆弧面的车胎工装.日常维护也是保证乳化液泵的正常工作的关键.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.