机械5

摘要 本设计是基于拖拉机倒挡拨叉零件的加工工艺规程及一些工序的专用夹具设计。拖拉机倒挡拨叉零件的主要加工表面是平面及孔系。一般来说，保证平面的加工精度要比保证孔系的加工精度容易。因此，本设计遵循先面后孔的原则。并将孔与平面的加工明确划分成粗加工和精加工阶段以保证孔系加工精度。基准选择以拖拉机倒挡拨叉的输入轴和输出轴的支承孔作为粗基准，以底面与两个工艺孔作为精基准。主要加工工序安排是先以支承孔系定位加工出顶平面，再以顶平面与支承孔系定位加工出工艺孔。在后续工序中除个别工序外均用顶平面和工艺孔定位加工其他孔系与平面。支承孔系的加工采用的是坐标法镗孔。整个加工过程均选用组合机床。夹具选用专用夹具，，机构可以不必自锁，因此生产效率较高，适用于大批量、流水线上加工，能够满足设计要求。 关键词：拖拉机倒挡拨叉类零件；工艺；夹具； ABSTRACT The desig
n is based o
n the body parts of the processi
ng order of the processes a
nd some special fixture desig
n. Body parts of the mai
n pla
ne of the surface a
nd pore system. I
n ge
neral, the pla
ne guara
ntee processi
ng precisio
n tha
n that of holes machi
ni
ng precisio
n easy. Therefore, this desig
n follows the surface after the first hole pri
nciple. Pla
ne with holes a
nd the processi
ng clearly divided i
nto roughi
ng a
nd fi
nishi
ng stages of holes to e
nsure machi
ni
ng accuracy. Datum selectio
n box i
nput shaft a
nd the output shaft of the supporti
ng hole as a rough be
nchmark, with top with two holes as a precisio
n tech
nology refere
nce. Mai
n processes arra
ngeme
nts to support holes for positio
ni
ng a
nd processi
ng the top pla
ne, a
nd the
n the top pla
ne a
nd the supporti
ng hole locatio
n hole processi
ng tech
nology. I
n additio
n to the follow-up processes i
ndividual processes are made of the top pla
ne a
nd tech
nological hole locatio
n hole a
nd pla
ne processi
ng. Supported hole processi
ng usi
ng the method of coordi
nate bori
ng. The whole process of processi
ng machi
ne combi
natio
ns were selected. Selectio
n of special fixture fixture, clampi
ng mea
ns more choice of p
neumatic clampi
ng, clampi
ng reliable, i
nstitutio
ns ca
n
not be locked, so the productio
n efficie
ncy is high, suitable for large batch, li
ne processi
ng, ca
n meet the desig
n requireme
nts. Key words: A
ngle gear seat parts; fixture; 摘要II ABSTRACT III 第1章绪论1 1.1机械加工工艺概述1 1.2机械加工工艺流程1 1.3夹具概述2 1.4机床夹具的功能2 1.5机床夹具的发展趋势3 1.5.1机床夹具的现状3 1.5.2现代机床夹具的发展方向3 第二章加工工艺规程设计4 2.1零件的分析5 2.1.1零件的作用5 2.2拖拉机倒挡拨叉加工的主要问题和工艺过程设计所应采取的相应措施6 2.2.1孔和平面的加工顺序6 2.2.2孔系加工方案选择6 2.3拖拉机倒挡拨叉加工定位基准的选择7 2.3.1粗基准的选择7 2.3.2精基准的选择7 2.4拖拉机倒挡拨叉加工主要工序安排8 2.5机械加工余量、工序尺寸及毛坯尺寸的确定11 2.6确定切削用量及基本工时（机动时间） 13 2.7时间定额计算及生产安排25 第三章铣槽夹具设计29 3.1研究原始质料29 3.2定位基准的选择29 3.3切削力及夹紧分析计算30 3.4误差分析与计算31 3.5定向键与对刀装置设计32 3.5夹具体的设计34 3.6夹具设计及操作的简要说明34 总结36 参考文献37