【正文】 到其最大值。影響兩工藝孔位置度的因素有（如下圖所示）：（1）、鉆模板上兩個(gè)裝襯套孔的尺寸公差：（2）、兩襯套的同軸度公差：（3）、襯套與鉆套配合的最大間隙：（4）、鉆套的同軸度公差：（5）、鉆套與鉸刀配合的最大間隙： 所以能滿足加工要求。將小車連同工件推入夾具中時(shí)，螺釘23起限位作用。由于夾緊缸由彈簧18支承并安裝在滑柱上，當(dāng)活柱鉆模板下降夾緊工件時(shí)，錐銷連同氣缸可以和工件一起下降。本夾具主要用來粗銑汽車變速箱箱體前后端面。本道工序僅是對前后端面進(jìn)行粗加工。因此工件選用頂面與兩工藝孔作為定位基面。工件以一面兩孔定位時(shí)，夾具上的定位元件是：一面兩銷。本工序選用的定位基準(zhǔn)為一面兩孔定位，所以相應(yīng)的夾具上的定位元件應(yīng)是一面兩銷。根據(jù)《機(jī)床夾具設(shè)計(jì)手冊》削邊銷與圓柱銷的設(shè)計(jì)計(jì)算過程如下：（1）、確定兩定位銷中心距尺寸及其偏差 == （2）、確定圓柱銷直徑及其公差 （—基準(zhǔn)孔最小直徑） 取f7 所以圓柱銷尺寸為 （3）、削邊銷的寬度b和B （由《機(jī)床夾具設(shè)計(jì)手冊》） （4）、削邊銷與基準(zhǔn)孔的最小配合間隙 其中： —基準(zhǔn)孔最小直徑 —圓柱銷與基準(zhǔn)孔的配合間隙（5）、削邊銷直徑及其公差 按定位銷一般經(jīng)濟(jì)制造精度，其直徑公差帶為，則削邊銷的定位圓柱部分定位直徑尺寸為 。其距離盡可能布置的遠(yuǎn)些。由于本道工序是完成汽車變速箱箱體前后端面的粗銑加工，所以選用直角對刀塊。根據(jù)所需要的夾緊力，來計(jì)算氣缸缸筒內(nèi)徑。本夾具用于汽車變速箱箱體前后端面的粗銑。工件用吊環(huán)在夾具體上安裝好后，壓塊在氣缸活塞的推動(dòng)下向下移動(dòng)夾緊工件。參考文獻(xiàn)[1] 許曉旸，專用機(jī)床設(shè)備設(shè)計(jì)，重慶：重慶大學(xué)出版社，2003。[5] 淘濟(jì)賢等，機(jī)床夾具設(shè)計(jì)，北京：機(jī)械工業(yè)出版社，1986。[9] 賀光誼等，畫法幾何及機(jī)械制圖，重慶：重慶大學(xué)出版社，1994。[13] 孟少龍，機(jī)械加工工藝手冊第1卷，北京：機(jī)械工業(yè)出版社，1991。[17] 上海金屬切削技術(shù)協(xié)會(huì)，金屬切削手冊，上海：上?？茖W(xué)技術(shù)出版社，1984。我萬分的感謝他們給我的寶貴的指導(dǎo)意見和鼓勵(lì)。在學(xué)習(xí)和生活上，他們一直都很支持我，使我能全身心地投入到學(xué)習(xí)中。 （2）、圖紙要求：汽車變速箱零件工作圖，兩套夾具裝配圖，夾具專用零件圖二到三張。 : 2005 年4 月5 日指導(dǎo)教師:陳廣凌 (簽名)指導(dǎo)教師:張彥博 (簽名)完成任務(wù)日期:2005 年6 月17 日學(xué)生:李尚勤 (簽名)附件2：畢業(yè)設(shè)計(jì)(論文)指導(dǎo)教師評語學(xué)生:_________學(xué)號:_________專業(yè):________年級:___指導(dǎo)教師評語:__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________指導(dǎo)教師簽名:________________20__年____月____日附件3：畢業(yè)設(shè)計(jì)(論文)評閱人評語學(xué)生:_________學(xué)號:_________專業(yè):________年級:___題目:___________________________________________________________________________________________評閱人評語:______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________評閱人簽名:_____________ 日期:20__年____月_____日附件4：畢業(yè)設(shè)計(jì)(論文)答辯小組評語學(xué)生:________學(xué)號:__________專業(yè):_________年級:___題目:___________________________________________________________________________________________答辯小組評語:______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________答辯成績:____________組長簽名:_____________外語文獻(xiàn)翻譯摘自: 《制造工程與技術(shù)（機(jī)加工）》（英文版） 《Manufacturing Engineering and Technology—Machining》 機(jī)械工業(yè)出版社 2004年3月第1版 美 s. 卡爾帕基安(Serope kalpakjian) 施密德(Steven ) 著原文： MACHINABILITYThe machinability of a material usually defined in terms of four factors: Surface finish and integrity of the machined part。 this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in resulfurized steels.Phosphorus in steels has two major effects. It strengthens the ferrite, causing increased hardness. Harder steels result in better chip formation and surface finish. Note that soft steels can be difficult to machine, with builtup edge formation and poor surface finish. The second effect is that increased hardness causes the formation of short chips instead of continuous stringy ones, thereby improving machinability.Leaded Steels. A high percentage of lead in steels solidifies at the tip of manganese sulfide inclusions. In nonresulfurized grades of steel, lead takes the form of dispersed fine particles. Lead is insoluble in iron, copper, and aluminum and their alloys. Because of its low shear strength, therefore, lead acts as a solid lubricant (Section ) and is smeared over the toolchip interface during cutting. This behavior has been verified by the presence of high concentrations of lead on the toolside face of chips when machining leaded steels.When the temperature is sufficiently highfor instance, at high cutting speeds and feeds (Section )—the lead melts directly in front of the tool, acting as a liquid lubricant. In addition to this effect, lead lowers the shear stress in the primary shear zone, reducing cutting forces and power consumption. Lead can be used in every grade of steel, such as 10xx, 11xx, 12xx, 41xx, etc. Leaded steels are identified by the letter L between the second and third numerals (for example, 10L45). (Note that in stainless steels, similar use of the letter L means “l(fā)ow carbon,” a condition that improves their corrosion resistance.)However, because lead is a wellknown toxin