机械制图测绘大作业指导书
机械零(部)件测绘指导书
第一节 概 述
一、部件测绘的目的和要求
(一)目的
《画法几何及机械制图》课程是研究机械图样的绘制与识读规律的一门实践性很强的技术基础课,旨在培养学生具有基本的绘制和阅读机械图样能力,因此,在教学过程中,除了系统地讲授基本知识、基本原理和方法外,还应使学生接受较全面的技能训练,即作部件测绘,它是理论联系实际的一个重要教学环节,其目的是:
(1)熟练掌握部件测绘的基本方法和步骤。
(2)进一步提高零件图和装配图的表达方法和绘图的技能技巧。
(3)提高零件图的上尺寸标注、公差配合及形位公差标注的能力,了解有关机械结构方面的知识。 (4)正确使用参考资料、手册、
标准
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及
规范
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等。
(5)培养独立分析和解决实际问题的能力, 为后继课程学习及今后工作打下基础。 (二)要求
在测绘中要求学生注意培养独立分析问题和解决问题的能力,且保质、保量、按时完成部件测绘任务,具体要求是:
(1)测绘前要认真阅读测绘指导书,明确测绘的目的、要求、 内容及方法和步骤。 (2)认真复习与测绘有关的内容,如视图表达、 尺寸测量方法、标准件和常用件、零件图与装配图等。 (3)认真绘图,保证图纸质量。做到正确、完整、清晰、整洁。
(4)做好准备工作,如测量工具、绘图工具、资料、手册、 仪器用品等。
(5)在测绘中要独立思考,一丝不苟,有错必改,反对不求甚解,照抄照搬,容忍错误的作法。 (6)按预定
计划
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完成测绘任务,所画图样经教师审查后方呈交。
二、测绘内容和进度计划
(一)测绘内容
减速器
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
(二)进度计划
本次测绘的工作量及进度计划见下表:
序号 内 容 图纸 时间(天)
布置测绘任务,分发绘图仪器,学习测绘注意事项,1 1.0 拆卸部件
2 2.0 画全部草图 (标准件除外)
3 箱体、箱盖工作图 A1一张 2.0
4 齿轮轴 A3二张 1.5
5 减速器装配图 A2一张 0.5
6 箱体、箱盖零件图;减速器装配图 CAD绘制 2.0
7 总结、验收、上交 1.0
A0一张 8 10.0 合 计 A3一张
第二节 了解和分析测绘对象
在测绘之前,首先要对部件进行全面的分析研究,通过观察、研究、分析该部件的结构和工作情况,及认真阅读指导书,这样可以了解部件的用途、性能、工作原理、结构特点,以及零件间的装配关系。 一、用途
主要用于降低转速。
二、工作原理
减速器是一种常用的减速装置。减速器的种类很多, 常用的有圆柱齿轮减速器和蜗轮蜗杆减速器。一级齿轮减速器是最简单的一种减速器。减速器工作时,回转运动是通过件 17(齿轮轴)传入,再经过件17上的小齿轮传递给件31(大齿轮),经件30(键)将减速后的回转运动传给27(轴),件27(轴)将回转运动传给工作机械。主动轴与被动轴两端均由滚动轴承支承;工作时采用飞溅润滑,改善了工作情况。件 9(垫片)、 件21(挡油环)、 件15、23(填料)是为了防止润滑油渗漏和灰尘进入轴承。件29(支承环)是防止件31(大齿轮)轴向窜动;件18、26(调整环)是调整两轴的轴向间隙。减速器机体、机盖用件1(销)定位,并用6对螺栓紧固。机盖顶部有观察孔,机体有放油孔。件20为观察润滑油面高度的油标。件13、14为排放污油用的零件。
第三节 拆卸部件和画装配示意图
一、拆卸部件
在初步了解部件的基础上,依次拆卸各零件,这样可以进一步搞清减速器部件中各零件的装配关系、结构和作用,弄清零件间的配合关系和配合性质。
finished products. In front of the project for the corresponding rules-miand partially completed finished or sefinished products. Education staff at the time of construction to respect other people and their work, cherish the completed -r moral education of the civilization production and the protection of the finished and semifinished products for education. Often quality education for workers, fo-g the protection of all the construction finished and semieening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancinng, grhe construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardenipublic relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around t12, ----ve progress in contradiction to consult each other when dealt with properly. 11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensi----gular inspection, timely scoring, reward. truction, "score", regular or not refocus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----construction site management and workers should wear distinctive markings. 10, security----level of security personnel on duty, fire security measures taken. 9, post signs2
注意:
(1)拆卸前应先测量一些重要的装配尺寸,如零件间的相对位置尺寸,两轴中心距、极限尺寸和装配间隙等。 (2)注意拆卸顺序,对精密的或主要零件,不要使用粗笨的重物敲击,对精密度较高的过盈配合零件尽量不拆,以免损坏零件。
(3)拆卸后各零件要妥善保管,以免损坏丢失。
二、画装配示意图
装配示意图是在部件拆卸过程中所画的记录图样,其作用是避免由于零件拆卸后可能产生错乱而给重新装配时带来困难,它是通过目测,徒手用简单的线条示意性地画出部件的图样,主要表达部件的结构、装配关系、工作原理、传动路线等,而不是整个部件的详细结构和各个零件的形状。画装配示意图时,应采用画法几何及机械制图国家标准“机构运动简图符号”(GB4460,84)中所规定的符号。
注意事项:
(1)图形画好后,应编上零件序号或名称。
(2)标准件应及时确定其尺寸规格。
第四节 绘制零件草图
绘制齿轮油泵 (标准件除外)所有零件的草图,标准件,只需测得几个主要尺寸,从标准中确定其规定标记。 一、画零件草图的基本要求及注意事项
零件草图是目测比例,徒手画出的零件图,它是实测零件的第一手资料,也是整理装配图与零件工作图的主要依据。草图不能理解为漆漆草草的图,而应认真地对待草图的绘制工作,零件草图满足以下两点要求: (1)零件草图所采用的表达方法、内容和要求与零件工作图一致。
(2)表达完整、线型分明、投影关系正确、字体工整、图面整洁。
画零件草图时注意事项:
(1)注意保持零件各部分的比例关系及各部分的投影关系。
(2)注意选择比例,一般按1:1画出,必要时可以放大或缩小。 视图之间留足注尺寸的位置。 (3)零件的制造缺陷,如刀痕、砂眼、气孔、及长期使用造成的磨损,不必画出。 (4)零件上因制造、装配需要的工艺结构,如倒角、倒园、退刀槽、铸造园角、凸台、凹坑等,必须画出。 二、视图选择的一般原则
finished products. In front of the project for the corresponding rules-and partially completed finished or semifinished products. Education staff at the time of construction to respect other people and their work, cherish the completed -mithe protection of the finished and sefinished products for education. Often quality education for workers, for moral education of the civilization production and -5dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semight <5tion site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB niipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construc12, public relations personnel to abide by social morality, professional ethics, business disc----other when dealt with properly. on and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each11, with coordination between the constructi----truction, "score", regular or not regular inspection, timely scoring, reward. focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----yconstruction site management and workers should wear distinctive markings. 10, securit----level of security personnel on duty, fire security measures taken. 9, post signs3
选择视图时,基本原则是:在完整、清晰地表达零件内、外形状结构的前提下,尽量减少图形数量,以便画图和看图。
(一)主视图的选择
主视图是表达零件最主要的一个视图,在选择主视图时应考虑以下两个方面。
(1)确定零件的安放位置, 其原则是尽量符合零件的主要加工位置和工作(安装)位置。这样便于加工和安装,通常对轴、套、盘等回转体零件选择其加工位置;对叉架、箱体类零件选择其工作位置。 (2)确定零件主视图的投射方向, 选择最能明显地反映零件形状和结构特征以及各组成形体之间的相互关系,这样能较快地看清楚零件的开关与结构。
(二)其它视图的选择
主视图选定以后,其它视图的选择考虑以下几点:
(1) 根据零件的内外结构和复杂程度全面地考虑所需要的其它视图,使每个视图有一个表达重点,注意采用的视图数目不宜过多,以免繁琐、重复,导致主次不分。
(2) 优先考虑用基本视图以及在基本视图以及在基本视图上作剖视图。
(3) 合理布置视图位置:使图样清晰美观又有利于图幅的充分利用。
三、作图步骤
(1)用2H铅笔画出各视图的对称中心线、作视图基准线。
)画零件的外形轮廓、主要结构部分。 (2
(3)画零件的细微结构部分,可采用局部视图、局部剖视、局部放大和剖面,简化画法等。 (4)认真检查,发现错误及时修正,然后用HB或B 铅笔按国家标准线型要求加深。 四、尺寸标注
零件图上的尺寸标注,要做到完整、清晰、符合标准,且能满足
设计
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要求和工艺要求。标注尺寸时应做到: (1)从设计要求和工艺要求出发,选择恰当的尺寸基准,不要注成封闭尺寸链。
(2)尺寸应尽量注在视图外边、两视图中间。
(3)部件中两零件有联系的部分,尺寸基准应统一。
(4)对于标准结构,如螺纹、退刀槽、轮齿、应把测量结果与标准核对,采用标准值。
finished products. In front of the project for the corresponding rules-miand partially completed finished or sefinished products. Education staff at the time of construction to respect other people and their work, cherish the completed -r moral education of the civilization production and the protection of the finished and semifinished products for education. Often quality education for workers, fo-g the protection of all the construction finished and semieening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancinng, grhe construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardenipublic relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around t12, ----ve progress in contradiction to consult each other when dealt with properly. 11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensi----gular inspection, timely scoring, reward. truction, "score", regular or not refocus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----construction site management and workers should wear distinctive markings. 10, security----level of security personnel on duty, fire security measures taken. 9, post signs4
(5)重要尺寸,如配合尺寸、定位尺寸、保证工作精度和性能的尺寸等,应直接标注出来。 (6)零件上一些常见结构,如底板、端面、法兰盘图形要按一定的标注方式进行尺寸标注。 五、技术要求
(一)材料
零件材料的确定,可根据实物结合有关标准、手册的分析初步确定。常用的金属材料有碳钢、铸铁、铜、铅、及其合金。参考同类型零件的材料,用类比法确定或参阅有关手册。
(二)表面粗糙度
零件表面粗糙度等级可根据各个表面的工作要求及精度等级来确定,可以参考同类零件的粗糙度要求或使用粗糙度样板进行比较确定,表面粗糙度等级时可根据下面几点决定:
(1)一般情况下,零件的接触表面比非接触表面的粗糙度要求高。
(2)件表面有相对运动时,相对速度越高所受单位面积压力越大,粗糙度要求越高。 )间隙配合的间隙越小,表面粗糙度要求应越高,过盈配合为了保证连接的可靠性亦应有较高要求的粗糙(3
度。
(4)在配合性质相同的条件下,零件尺寸越小则粗糙度要求越高,轴比孔的粗糙度要求高。 (5)要求密封、耐腐蚀或装饰性的表面粗糙度要求高。
(6)受周期载荷的表面粗糙度要求应较高。
(三)形位公差
标注形位公差时参考同类型零件,用类比法确定,无特殊要求时一律不标注。参阅有关手册 (四)公差配合的选择
参考相类似的部件的公差配合,通过分析比较来确定。我们测绘的减速器中,齿轮与轴之间,滚动轴承轴承座与箱体孔之间,,轴承内圈与轴之间都有配合要求,选择时可参考有关手册。 (五)技术要求
凡是用符号不便于表示,而在制造时或加工后又必须保证的条件和要求都可注写在“技术要求”中,其内容参阅有关资料手册,用类比法确定。
第五节 尺寸测量与尺寸数字处理
一、尺寸测量
finished products. Education staff at the time of construction to respect other people and their work, cherish the completed -mithe protection of the finished and sefinished products for education. Often quality education for workers, for moral education of the civilization production and -5dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semight <5tion site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB niipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construc12, public relations personnel to abide by social morality, professional ethics, business disc----other when dealt with properly. on and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each11, with coordination between the constructi----truction, "score", regular or not regular inspection, timely scoring, reward. focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----yconstruction site management and workers should wear distinctive markings. 10, securit----level of security personnel on duty, fire security measures taken. 9, post signsfinished products. In front of the project for the corresponding rules-and partially completed finished or semi5
在测量零件时,应根据零件尺寸的精确程度选用相应的量具,常用的测量工具有游标卡尺、外卡、内卡、直尺、角度规、螺纹规等,精度低的尺寸可用内、外卡及钢尺测量,精度较高的尺寸应采用游标卡尺进行测量。 注意事项:
(1)测量时应尽量从基准出发减少测量误差。
(2)尽量避免尺寸换算以减少错误。
二、尺寸数字处理
零件的尺寸有的可以直接量得,有的要经过一定的运算后才能得到,如中心距等,测量所得的尺寸还必须进行尺寸处理:
(1)一般尺寸,大多数情况下要圆整到整数。
(2)重要的直径要取标准值。
(3)对标准结构(如螺纹、键槽、齿轮的轮齿)的尺寸要取相应的标准值。
(4)没有配合关系的尺寸或不重要的尺寸,一般圆整到整数。
(5)有配合关系的尺寸(配合孔轴)只测量它的基本尺寸,其配合性质和相应公差值,查阅手册。 (6)有些尺寸要进行复核,如齿轮传动轴孔中心距要与齿轮的中心距核对。
(7)因磨损、碰伤等原因而使尺寸变动的零件要进行分析,标注复原后的尺寸。
)零件的配合尺寸要与相配零件的相关尺寸协调,即测量后尽可能将这些配合尺寸同时标注在有关的零件(8
上。
第六节 绘制部件装配图
根据零件草图和装配示意图画出部件装配图。在画装配图时,要及时改正草图上的错误,零件的尺寸大小一定要画得准确,装配关系不能搞错,这是很重要的一次校对工作,必须认真仔细。具体步骤如下: 一、确定表达
方案
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由于装配图不仅表达了部件的工作原理,各零件的装配关系,而且反映了主要零件的形状结构,所以我们应根据已学过的装配图的各种表达方法(包括一些特殊的表达方法,如拆卸画法、夸大画法, 简化画法等),选用适合的表达方法,较好地反映部件装配关系、 工作原理和主要零件的结构形状,根据前面对减速器的表达分析,主视图按工作位置选定,采用局部剖,主要表达装配关系,俯视图可采用拆卸画法。 二、画装配图的步骤
(一)合理布局
finished products. In front of the project for the corresponding rules-miand partially completed finished or sefinished products. Education staff at the time of construction to respect other people and their work, cherish the completed -r moral education of the civilization production and the protection of the finished and semifinished products for education. Often quality education for workers, fo-g the protection of all the construction finished and semieening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancinng, grhe construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardenipublic relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around t12, ----ve progress in contradiction to consult each other when dealt with properly. 11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensi----gular inspection, timely scoring, reward. truction, "score", regular or not refocus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----construction site management and workers should wear distinctive markings. 10, security----level of security personnel on duty, fire security measures taken. 9, post signs6
装配图的表达方法确定后,应根据具体部件真实大小及其结构的复杂程度,确定合适的比例和图幅,选定图幅时不仅要考虑到视图所需的面积,而且要把标题栏、明细表、零件序号、标注尺寸和注写技术要求的位置一并计算在内,确定用哪一号图纸幅面后即可着手合理的布置图面。通常先画出各主要视图的作图基准线,如齿轮油泵在主视图上先画出泵体的外轮廓线以及两根轴线,这样就决定了主视图的高低,再画左视图泵体轴线等。
(二)画出部件的主要结构部分
如减速器的装配图可先画主视图上的箱座和箱盖的结构,再依次画出其他一系列零件,将零件逐个画在装配图上时,要考虑零件的相对位置和装配顺序。
在画部件的主要结构时,一般是每个视图分别作图,但亦应注意各视图间的投影关系。有些零件如有条件在各个视图上同时画时,应尽可能一起画出以节约时间。
(三)画出部件的次要结构部分
如减速器主视图上的螺栓、螺钉等结构。
(四)检查校核
除了检查零件的主要结构外,特别要注意视图上细节部分的投影是否遗漏或错误。由于装配图图形复杂,线条较多容易漏画部分投影。应认真检查,发现错误及时修改。
(五)完成全图
检查底稿后加深图线并画剖面代号;注写必要的尺寸、公差配合和技术要求;标注序号,填写标题栏及明细表。最后完成减速器装配图。
三、尺寸标注
装配图主要是设计和装配机器或部件时用的图样,因此不必注出零件的全部尺寸,只需标出一些必要的尺寸。如特征尺寸、装配尺寸、安装尺寸、外形尺寸和其它重要尺寸等,具体参阅有关手册。 四、技术要求及性能
(一)技术要求
不同性能的机器或部件,其技术要求也不同,一般可以从以下几个方面来考虑:
(1)装配要求
装配后必须保证的准确度和装配时的要求及需要在装配时的加工说明。
(2)检验要求
-5dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semight <5tion site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB niipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construc12, public relations personnel to abide by social morality, professional ethics, business disc----other when dealt with properly. on and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each11, with coordination between the constructi----truction, "score", regular or not regular inspection, timely scoring, reward. focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----yconstruction site management and workers should wear distinctive markings. 10, securit----level of security personnel on duty, fire security measures taken. 9, post signsfinished products. In front of the project for the corresponding rules-and partially completed finished or semifinished products. Education staff at the time of construction to respect other people and their work, cherish the completed -mithe protection of the finished and sefinished products for education. Often quality education for workers, for moral education of the civilization production and 7
基本性能的检验方法和要求,装配后必须保证达到的准确度,关于检验方法的说明,其他检验要求等。 (3)使用要求
对产品的基本性能、维护、保养的要求以及使用操作时的注意事项等。
上述各项内容,并不要求装配图全部注写,要根据具体情况而定,如已在零件图件图上提出的技术要求在装配上一般可以不必注写。
技术要求一般写在明细表上方或图纸下方的某空白处,也可以另编技术文件,附于图纸。 五、注意事项
(1)合理选择装配工艺结构,参阅有关手册。
(2)采用画法几何及机械制图国家标准中的简化画法。
(3)为表达清楚起见,采用1:1绘制。
第七节 绘制零件工作图
由于测绘是在现场进行的,所画的草图不一定是很完善的,所以在画零件工作图之前,要对草图进行全面审查、核对,对测量所得的尺寸,要参照标准直径、标准长度系列贴近、园整。对于标准结构要素的尺寸,应从有关标准中查对校正。有的问题需重新考虑,如表达方案、尺寸标注等。经过复查、补充、修改后,再进
行零件图的绘制工作。
画零件工作图的方法步骤:
)定比例:根据零件的复杂程度和尺寸大小,确定画图比例。 (1
(2)选图幅:根据表达方案及所选定的比例,估计各图形布置所占的面积,对所需标注的尺寸留有余地,选择合理的图幅。
(3)画底稿:先定出各视图的基准线,再画图。
)检查、描深。 (4
(5)标注尺寸,注写技术要求,填写标题栏。
第八节 图纸折叠
为了便于保存和携带,画好的图纸应按国标A4图纸幅面尺寸 210×297折迭。后装订好连同草图一起装入资料袋内。
finished products. In front of the project for the corresponding rules-miand partially completed finished or sefinished products. Education staff at the time of construction to respect other people and their work, cherish the completed -r moral education of the civilization production and the protection of the finished and semifinished products for education. Often quality education for workers, fo-g the protection of all the construction finished and semieening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancinng, grhe construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardenipublic relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around t12, ----ve progress in contradiction to consult each other when dealt with properly. 11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensi----gular inspection, timely scoring, reward. truction, "score", regular or not refocus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of cons----construction site management and workers should wear distinctive markings. 10, security----level of security personnel on duty, fire security measures taken. 9, post signs8