机械5

摘要 夹具是零件加工的夹紧装置，是加工零件的一种必不可少的装置。随着零件的尺寸变化，越来越多的夹具被淘汰了，因此，设计一套专用夹具是十分有必要的。在设计专用夹具时要考虑工件的定位方案，工件的夹紧方案和设计夹紧机构，夹具的其他组成部分，夹具的结构形式等。 本课题的主要研究内容是一四挡变速叉零件的加工工艺分析及铣叉口两端面夹具设计。结合零件加工的重点和难点，从零件的结构分析入手，了解零件的工艺再设计出毛坯的结构，并选择好零件的加工基准，设计出零件的工艺路线；接着对零件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；加工工时，填写工艺过程卡片和工序卡片。然后对铣叉口两端面这个工序进行专用夹具设计，选好定位基准，设计出定位元件，对切削力计算及夹紧力分析。对定位时产生的定位误差分析，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：专用夹具、变速叉、加工工艺、工艺路线、切削用量 Abstract Fixture is a clampi
ng device for parts processi
ng, a
nd it is a
n i
ndispe
nsable device for parts processi
ng. With the size cha
nge of parts, more a
nd more fixtures are elimi
nated, so it is
necessary to desig
n a set of special fixtures. Whe
n desig
ni
ng special fixture,we should co
nsider the positio
ni
ng scheme ofworkpiece, the clampi
ng scheme ofworkpiece a
nd the clampi
ng mecha
nism, the other compo
ne
nts of fixture, the structure form of fixture, etc. The mai
n research co
nte
nt of this subject is the processi
ng tech
nology a
nalysis of a four-speed fork part a
nd the desig
n of two-e
nd fixture for the milli
ng fork. Combi
ni
ngwith the key poi
nts a
nd difficulties of parts processi
ng, starti
ng from the structural a
nalysis of parts, the process of parts is u
nderstood a
nd the structure of bla
nks is redesig
ned, a
nd the process route of parts is desig
ned by choosi
ng the processi
ng be
nchmark of parts. The
n the dime
nsio
n calculatio
n of each step of parts is carried out, a
nd the key is to determi
ne the process equipme
nt a
nd equipme
nt of each step. Cutti
ng parameters;worki
ng hours, filli
ng i
n process cards a
nd process cards. The
n the special fixture desig
n is carried out for the two e
nd faces of the milli
ng fork. The positio
ni
ng datum is selected, the positio
ni
ng eleme
nts are desig
ned, a
nd the cutti
ng force calculatio
n a
nd clampi
ng force a
nalysis are carried out. The positio
ni
ng error caused by positio
ni
ng is a
nalyzed, the ratio
nality a
nd shortcomi
ngs of fixture structure are a
nalyzed, a
nd atte
ntio
n should be paid to improveme
nt i
n future desig
n. Keywords: special fixture, tra
nsmissio
n fork, processi
ng tech
nology, process route, cutti
ng parameters 目录 摘要I Abstract II 第1章引言1 1.1机床夹具的概述1 1.2机床夹具的发展方向1 1.3机床夹具在机械加工中的作用2 1.4夹具设计的特点和基本要求2 第2章计算生产纲领、确定生产类型4 2.1生产纲领4 2.2生效率分析4 2.3生产类型5 第3章零件的分析6 3.1零件的作用6 3.2零件的工艺分析6 3.3零件的结构工艺性分析7 第4章工艺规程设计8 4.1确定毛坯的制造形式及毛坯余量选定8 4.2基面的选择9 4.3确定各工序的加工余量10 4.4制订工艺路线10 4.5确定切削用量以及时间定额11 第5章铣床夹具设计24 5.1问题的提出24 5.2定位基准的选择24 5.3定位元件的设计24 5.4定位误差分析26 5.5切削力的计算与夹紧力分析27 5.6夹具设计及操作简要说明27 结论28 谢辞29 参考文献29