机械5

摘要 本次设计内容涉及倒挡拨叉的机械制造工艺及工装夹具设计的内容。 根据倒挡拨叉的零件图分析其精度、表面粗糙度、技术要求、加工部位尺寸、形状结构及零件的批量生成的，确定被加工零件工艺方法和工艺过程，并选择好倒挡拨叉的加工基准，设计出倒挡拨叉的工艺路线；接着对倒挡拨叉各个工步的工序进行尺寸计算，关键是决定出各个工序的工艺装备及切削用量和基本工时；然后进行专用夹具的设计，在选择设计出夹具中，本次针对倒挡拨叉的工艺确定设计两套夹具。此两套夹具分别是铣叉口两侧面的夹具。在设计夹具过程中，需要考虑的是如定位元件、夹紧元件、夹具体、对刀件以及其它部件；计算出夹具定位时产生的定位误差，分析夹具结构的合理性与不足之处，并在以后设计中注意改进。 关键词：倒挡拨叉；工装夹具；工艺规程 Abstract This desig
n i
nvolves the mecha
nical ma
nufacturi
ng process of the reverse shift fork a
nd the desig
n of the fixture. Accordi
ng to the part drawi
ng of the reverse shift fork, a
nalyze its accuracy, surface rough
ness, tech
nical requireme
nts, processi
ng part size, shape structure a
nd batch ge
neratio
n of parts, determi
ne the process method a
nd process of the processed parts, select the processi
ng be
nchmark of the reverse shift fork, a
nd desig
n the process route of the reverse shift fork; the
n calculate the size of each process step of the reverse shift fork, the key is to Determi
ne the process equipme
nt, cutti
ng parameters a
nd basic worki
ng hours of each process; the
n carry out the desig
n of special fixture. I
n the selectio
n a
nd desig
n of fixture, two sets of fixture are desig
ned for the process of reverse shift fork. The two sets of jigs are respectively the jigs o
n both sides of the milli
ng fork. I
n the process of desig
ni
ng fixture, it is
necessary to co
nsider positio
ni
ng eleme
nts, clampi
ng eleme
nts, clampi
ng details, tool setti
ng parts a
nd other parts; calculate the positio
ni
ng error ge
nerated i
n fixture positio
ni
ng, a
nalyze the ratio
nality a
nd shortcomi
ngs of fixture structure, a
nd pay atte
ntio
n to improveme
nt i
n the future desig
n. Key words: reverse shift fork, fixture, process specificatio
n 目录 摘要ii Abstract iii 目录iv 第一章绪论- 6 - 1.1设计目的- 6 - 1.2研究的内容和意义- 6 - 1.3目前国内外存在的现状及存在的问题- 6 - 第二章零件的分析- 8 - 2.1零件的作用- 8 - 2.2零件的工艺分析- 8 - 第三章确定毛坯形式- 10 - 3.1选择毛坯- 10 - 3.2确定机械加工余量，毛坯尺寸和公差- 10 - 3.3设计毛坯图- 10 - 第四章选择加工方法制定加工工艺路线- 12 - 4.1定位基准的选择- 12 - 4.1.2粗基准的选择- 12 - 4.1.3精基准的选择- 12 - 4.2零件表面加工方法的选择- 13 - 4.3制定工艺路线- 13 - 4.4确定夹具、量具- 16 - 4.5确定工序尺寸- 17 - 第五章确定切削用量及基本时间- 18 - 5.1切削用量的选择- 18 - 5.2各工序的切削用量及时间定额- 18 - 第六章部分工序专用夹具设计- 25 - 6.1机床夹具简介- 26 - 6.1.1机床夹具的概述- 26 - 6.1.2专用夹具的组成- 26 - 6.1.3机床夹具设计要求- 26 - 6.1.4专用机床夹具的设计步骤- 26 - 6.2卧式铣床上精铣叉口侧面夹具- 27 - 6.2.1定位基准的选择- 28 - 6.2.2定位元件的设计- 28 - 6.2.3切削力及夹紧力的计算- 29 - 6.2.4定位误差分析- 30 - 6.2.5定向键装置设计- 31 - 6.2.6对刀装置设计- 32 - 6.2.7夹紧装置的设计- 32 - 结论- 35 - 参考文献- 36 - 致谢- 37 -