CA6140車床撥叉831008夾具設(shè)計,ca6140,車床,夾具,設(shè)計
湖南科技大學畢業(yè)設(shè)計說明書
摘 要
撥叉的加工質(zhì)量將直接影響機器的性能和使用壽命。本次設(shè)計旨在提高CA6140車床撥叉的加工效率，由此我們首先對撥叉的結(jié)構(gòu)特征和工藝進行了仔細的分析，然后確定了一套合理的加工方案，加工方案要求簡單，操作方便，并能保證零件的加工質(zhì)量。在制定加工工藝規(guī)程的順序如下：
1分析零件；
2選擇毛坯；
3設(shè)計工藝規(guī)程：包括制定工藝路線，選擇基準面等；
4工序設(shè)計：包括選擇機床，確定加工余量，工序尺寸及毛坯尺寸，確定切削用量及計算基本工時等；
5編制工藝文件。
此外，為了提高勞動生產(chǎn)率，降低勞動強度，保證加工質(zhì)量，需設(shè)計專用夾具，本次設(shè)計選擇了第六道工序銑斷雙體的專用夾具設(shè)計，以滿足加工過程的需要。
關(guān)鍵詞：撥叉; 工藝規(guī)程; 夾具設(shè)計
Abstract
Dials the fork processing quality directly will affect the machine the performance and the service life. This design is for the purpose of enhancing the CA6140 Lathe machine Dials the fork the processing efficiency, first has carried on the careful analysis from this us to the Dials the fork structure characteristic and the craft, then had determined set of reasonable processings plans, the processing plan request are simple, the ease of operation, and can guarantee the components the processing quality. In formulation processing technological process order as follows:
1 analysis the components;
2 choices semifinished materials;
3 designs technological process: Including division Craft route, preferred orientation datum and so on;
4 working procedures designs: Including chooses the engine bed, the determination processing remainder, the computation working procedure size and its the Semifinished materials size, the determination cutting specifications and the computation man-hour and so on;
5 establishments technological document.
In addition, in order to enhance the labor productivity, reduces the labor intensity, guaranteed the processing quality, must design the unit clamp, this design chose the six working procedure to The mill breaks Catarmaran Special-purpose jig design, by satisfied the processing process the need.
Key words: Dials the fork; technological process; jig desin。
目 錄
摘 要··························································································································································1
前 言···························································································································································4
1 零件的分析········································································································································5
1．1 零件的作用····································································································································5
1．2 零件的工藝分析····························································································································5
2 工藝規(guī)程的設(shè)計·······························································································································6
2．1 毛坯的制造形式····························································································································6
2．2 基準面的選擇································································································································6
2．2．1 粗基準的選擇······················································································································6
2．2．2 精基準的選擇······················································································································6
2．3 制定工藝路線································································································································6
2．4 機械加工余量、工序尺寸及毛坯尺寸的確定············································································8
2．5 確定切削用量及基本工時············································································································8
3 繪制零件圖和編制工藝卡············································································································26
3．1 繪制零件圖···································································································································26
3. 2 編制工藝文件·································································································································26
4 夾具設(shè)計············································································································································28
4．1 問題的提出·································································································································28
4．2 夾具體設(shè)計·································································································································28
4．2．1 定位基準的選擇·················································································································28
4．2．2 切削力及夾緊力的計算·····································································································28
4．2．3 定位誤差分析·····················································································································30
4．2．4 夾具設(shè)計及操作的簡要說明·····························································································30
5 結(jié)論·····················································································································································32
6 致謝·····················································································································································33
7 參考文獻···········································································································································34
前 言
畢業(yè)設(shè)計是學生在學校完成了大學四年的全部課程，并在進行了生產(chǎn)實習的基礎(chǔ)上進行的一個教學環(huán)節(jié)，也是學生在校學習階段的最后一個重要的教學環(huán)節(jié)，是完成工程師基本訓練的一個必不可少的過程。通過畢業(yè)設(shè)計培養(yǎng)學生綜合運用所學知識獨立解決本專業(yè)一般工程技術(shù)問題的能力，樹立正確的設(shè)計思想和工作作風。
畢業(yè)設(shè)計是在畢業(yè)實習的基礎(chǔ)上進行的，根據(jù)自己的設(shè)計課題，在畢業(yè)實習期間認真調(diào)查研究、搜索資料。
本次設(shè)計是提高CA6140車床上撥叉的加工效率，設(shè)計正確的加工工藝路線，以及某道工序的夾具。這次設(shè)計涉及到機床，機械加工工藝，工裝夾具等機制專業(yè)的幾乎所有的專業(yè)基礎(chǔ)知識。是一次全面地，系統(tǒng)地檢查自己在大學期間對專業(yè)知識學習的情況，在整個設(shè)計過程中做到嚴謹認真，一絲不茍的精神，盡量使自己的設(shè)計達到理想的水平，通過獨立的查找資料，分析，計算完成方案設(shè)計，圖紙設(shè)計和編寫技術(shù)文件等，設(shè)計了這套比較完整的加工工藝路線，使自己對機制專業(yè)有了更深刻的認識。
由于時間短促，經(jīng)驗不足以及水平有限，本次設(shè)計難免許多不妥和錯誤之處，敬請批評指正，以便及時改正。
1.零件分析
1.1 零件的作用
題所給的是CA6140車床上的撥叉，它位于車床變速機構(gòu)中，主要起換擋作用，使主軸回轉(zhuǎn)運動按照工作者的要求工作，獲得所需的速度和扭矩。零件上方的Φ20mm的孔與操作機構(gòu)相連，下方的Ф50mm的半孔則是用于與所控制齒輪所在的軸接觸，通過上方的力撥動下方的齒輪變速，兩零件鑄造為一體，加工時分開。
1.2 零件的工藝分析
CA6140車床上的撥叉共有兩處加工表面。其間有一定的位置要求，分述如下：
1.2.1 以Ф20mm為中心的加工表面
這一組加工表面包括：Ф20mm的孔，以及其上下表面，孔壁上有一個裝配時要鉆鉸的Ф8mm的錐孔，一個M6的螺紋孔，和一個缺口。
1.2.2 以Ф50mm為中心的加工表面
這一組加工表面包括：Ф50mm的孔，以及其上、下端面；
這兩組表面有一定的位置要求；
（1） Ф50mm的孔的上、下表面與Ф20的孔的垂直度誤差為0.07mm。
（2） Ф20mm的孔的上、下表面與Ф20的孔的垂直度誤差為0.05mm。
（3） Ф50mm、Ф20mm的孔的上、下表面以及Ф50mm的孔的內(nèi)表面的粗糙度誤差為3.2um。
（4） Ф20mm的孔的內(nèi)表面的粗糙度誤差為1.6um，精度為IT7。
2. 工藝規(guī)程設(shè)計
2.1 毛坯的制造形式
零件材料為HT200，考慮零件在機床運行過程中所受沖擊不大，零件結(jié)構(gòu)又比較簡單，故選擇鑄件毛坯。 圖一 毛坯圖
2.2 基準面的選擇
2.2.1 粗基準的選擇 對零件而言，盡可能選擇不加工表面為粗基準，而對若干個不加工表面的工件，則應(yīng)以與加工表面要求相對位置精度較高的不加工表面作粗基準，根據(jù)這個基準原則，現(xiàn)取Ф20mm的孔的不加工外輪廓表面作為粗基準，利用一組共兩個短V形塊支承兩個Ф20mm孔的外輪廓作主要定位面，以消除3個自由度，再用一個支承板支撐在Ф72mm的上表面，以消除3個自由度。
2.2.2 精基準的選擇 主要應(yīng)考慮基準重合問題。當設(shè)計基準不重合時，應(yīng)該進行尺寸換算，這在以后還要專門計算，此處不再重復。
2.3 制定工藝路線
制定工藝路線的出發(fā)點，應(yīng)當是使零件的幾何形狀、尺寸精度及位置精度等技術(shù)要求能得到合理的保證。在生產(chǎn)綱領(lǐng)已確定為中批生產(chǎn)的條件下，可以考慮采用萬能性機床配以專用夾具，并盡量使工序集中來提高生產(chǎn)率。除此以外，還應(yīng)當考慮經(jīng)濟效果，以便使生產(chǎn)成本盡量下降。
1、 工藝路線方案一：
工序一：退火
工序二：粗、精銑Ф20 mm、Ф50 mm的下表面，保證其粗糙度為3.2 um
工序三：以Ф20 mm的下表面為精基準，粗、精銑Ф20 mm的孔的上表面，保證其粗糙度為3.2 um,其上、下表面尺寸為30mm，
工序四：以Ф20 mm 的下表面為精基準，鉆、擴、鉸、精鉸Ф20 mm的孔，保證其內(nèi)表面粗糙度為1.6 um，垂直度誤差不超過0.05mm
工序五：以Ф20 mm的下表面為精基準，粗、半精鏜Ф50 mm的孔，保證其內(nèi)表面粗糙度為3.2 um
工序六；以Ф20 mm的下表面為精基準，粗、精銑Ф50 mm的上表面，保證其與孔的垂直度誤差不超過0.07mm，其上、下表面尺寸為12mm
工序七：銑斷
工序八：以Ф20 mm的孔為精基準，鉆Ф8 mm的錐孔的一半Ф4 mm，裝配時鉆鉸
工序九：以Ф20mm的孔為精基準，鉆Ф5mm的孔，攻M6的螺紋
工序十：以Ф20 mm的孔為精基準，銑缺口，保證其粗糙度為12.5um
工序十一：檢查
上面的工序可以是中批生產(chǎn)，但是其效率不高，并且工序四中的鉆孔方法在鉆孔是可能會偏離中心。經(jīng)綜合考慮，采用下面的方案二。
工藝路線方案二：
工序一；退火
工序二：粗、精銑Ф20 mm、Ф50 mm的下表面，保證其粗糙度為3.2 um
工序三：以Ф20 mm的下表面為精基準，粗、精銑Ф20 mm、Ф50 mm的孔的上表面，保證其粗糙度為3.2 um，Ф20 mm的上、下表面尺寸為30mm，Ф50 mm的上、下表面尺寸為12mm
工序四：以Ф20 mm 的下表面為精基準，鉆、擴、鉸、精鉸Ф2 0 mm的孔，保證其內(nèi)表面粗糙度為1.6 um，垂直度誤差不超過0.05 mm
工序五：以Ф20 mm 的下表面為精基準，粗、半精鏜Ф50 mm的孔，保證其內(nèi)表面粗糙度為3.2 um
工序六：銑斷
工序七：以Ф20 mm的孔為精基準，鉆Ф8 mm的錐孔的一半Ф4 mm，裝配時鉆鉸
工序八：以Ф20 mm的孔為精基準，鉆Ф5 mm的孔，攻M6的螺紋
工序九：以Ф20 mm的孔為精基準，銑缺口，保證其粗糙度為12.5 um
工序十：檢查
2.4 機械加工余量、工序尺寸及毛坯尺寸的確定
“CA6140車床撥叉”零件的材料為HT200硬度為190~210HB，毛坯重量為2.2Kg,生產(chǎn)類型為中批量，鑄件毛坯。又由<<機械制造工藝設(shè)計簡明手冊>>（以下稱〈〈工藝手冊〉〉表1.3-1查得毛坯的制造方法采用殼模鑄造級，表2.2-4查得加工余量等級為G級，選取尺寸公差等級為CT10。
根據(jù)以上資料及路線，分別確定各加工表面的機械加工余量、工序尺寸及毛坯如下：
1、延軸線方向長度方向的加工余量及公差（Ф20mm、Ф50mm端面） 查《工藝手冊》表2.2~4取Ф20mm、Ф50mm端面長度余量為2.5mm(均為雙邊加工)。
銑削加工余量為：a)粗銑：1.5mm b)精銑：1mm
毛坯尺寸及公差為：（35土0.3）mm （ 17土0.25）mm
2、內(nèi)孔（Ф50mm已鑄成孔）查《工藝手冊》表2.2~2.5，取Ф50mm已鑄成長度余量為3mm，即已鑄成孔Ф44mm。
鏜削加工余量為：a)粗鏜：2mm b)半精鏜：1mm
毛坯尺寸及公差為：（48土0.3）mm （）mm
3、其他尺寸直接鑄造得到。
2.5 確定切削用量及基本工時
2.5.1 工序二：粗、精銑孔Ф20mm、Ф50mm的下表面
（1） 加工條件
工件材料：HT200。бb=0.16GPa HBS=190~210，鑄件
機床：XA5032立式銑床
刀具；W18Cr4V硬質(zhì)合金端銑刀
W18Cr4V硬質(zhì)合金端銑刀，牌號為YG6，由《切削用量簡明手冊》〉后稱《切削手冊》表3.1查得銑削寬度ae<=60mm,深度ap<=4,齒數(shù)Z=10時，取刀具直徑do=80mm。又由《切削手冊》表3.2選擇刀具的前角ro=+5o;后角ao=8o;副后角a’o=,刀齒斜角λs=-10o,主刃Kr=60o,過渡刃Krε=30o,副刃Kr’=5o,過渡刃寬bε=1mm
(2) 切削用量
1）粗銑Ф20mm的下表面
a)切削深度 因切削用量較小，故可以選擇ap=1.5mm,一次走刀即可完成所需尺寸。
b)每齒進給量：由《切削手冊》表3.30可知機床的功為7.5KW，查《切削手冊》表3.5可得f=0.14~0.24mm/z,由于是對稱銑，選較小量f=0.14mm/z
c)查后刀面最大磨損及壽命
查《切削手冊》表3.7，后刀面最大磨損為（1.0~1.5）mm
查《切削手冊》表3.8, 壽命T=180min
d)計算切削速度 按《切削手冊》表3.27中的公式：
也可以由表3.16查得=98mm/s n=439r/min vf =490mm/s 又根據(jù)XA5032銑床參數(shù)，選 n=475r/min vf =600mm/s，則實際的切削速度為：
即==119.3m/min,實際進給量為：
即==0.13mm/z
e)校驗機床功率 查《切削手冊》表3.24，Pcc=1.1KW,而機床所提供的功率Pcm為1.7KW，所以Pcm> Pcc,故校驗合格。
最終確定ap=1.5mm nc=475r/min vfc=600mm/min vc=119.3m/min fz=0.13mm/z
f)計算基本工時
公式中： L=l+y+Δ；根據(jù)《切削手冊》表3.26，可得 l+Δ=12mm,所以L=l+y+Δ=32+12=44mm
故 =44/600=0.073min
2)粗銑Ф50mm的下表面
a)銑削Ф50mm的下表面與銑削Ф20mm的下表面的相關(guān)參數(shù)及其用量等都相同。即 ap=1.5mm nc=475r/min vfc=600mm/s vc=119.3m/min fz=0.13mm/z
b)計算基本工時
公式中： L=l+y+Δ；根據(jù)《切削手冊》表3.26，可得 l+Δ=0所以L=l+y+Δ=72mm
故 =72/600=0.12min
3)精銑孔Ф20mm的下表面
a) 切削深度 因切削用量較小，故可以選擇ap=1.0mm, 一次走刀即可完成所需尺寸
b)每齒進給量：由《切削手冊》表3.30可知機床的功為7.5KW，查《切削手冊》表3.5可得f=0.5~0.7mm/r，由于是對稱銑，選較小量f=0.7mm/r
c)查后刀面最大磨損及壽命
查《切削手冊》表3.7，后刀面最大磨損為（1.0~1.5）mm
查《切削手冊》表3.8, 壽命T=180min
d)計算切削速度 按《切削手冊》表3.27中的公式：
也可以由表3.16查得=124mm/s vf =395mm/min n=494r/min,根據(jù)XA5032銑床參數(shù)，選 n=475r/min vf =375mm/min , 則實際的切削速度為
所以==119.3m/min,實際進給量
所以==0.08mm/z
e)校驗機床功率 查《切削手冊》表3.24，Pcc=1.1KW,而機床所提供的功率Pcm為1.7KW，所以Pcm> Pcc,故校驗合格。
最終確定ap=1.0mm nc=475r/min vfc=375mm/min vc=119.3mm/min
f)計算基本工時
公式中： L=l+y+Δ；根據(jù)《切削手冊》表3.26，可得 l+Δ=80mm, 所以L=l+y+Δ=32+80=112mm
故 =112/375=0.3min
2)精銑Ф50mm的下表面
a)銑削Ф50mm的下表面與銑削Ф20mm的下表面的相關(guān)參數(shù)及其用量等都相同。即 ap=1.0mm nc=475r/min vfc=375mm/min vc=119.3mm/m
b)計算基本工時
公式中： L=l+y+Δ；根據(jù)〈〈切削手冊〉〉表3.26，可得 l+Δ=80mm所以L=l+y+Δ=72+80=152mm
故 =152/375=0.405min
2.5.2 工序三：粗、精銑孔Ф20mm、Ф50mm的上表面
本工序的切削用量及基本工時與工序一中的粗、精銑孔Ф20mm、Ф50mm的下表面相同。
2.5.3 工序四：鉆、擴、鉸、精鉸Ф20mm的孔
（一） 鉆Ф18mm的孔
（1）加工條件
工藝要求：孔徑d=18mm, 孔深l=30mm,通孔 ，用乳化液冷卻
機床 ：Z535型立式鉆床
刀具 ：高速鋼麻花鉆頭
選擇高速鋼麻花鉆頭，其直徑do=18mm,鉆頭幾何形狀為：由《切削手冊》表2.1及表2.2 選修磨橫刃，β=28o αo=10o 2Φ=118o 2Φ1=70o bε=3.5mm b=2mm l=4mm
(2) 切削用量
1) 決定進給量f
a)、按加工要求決定進給量 根據(jù)《切削手冊》表2.7，當鑄鐵的強度
бb200HBS do=18mm時，f=0.70~0.86mm/r
由于L/d=30/18=1.67<3,故取修正系數(shù)K=1
所以 f=(0.70~0.86)x1=(0.70~0.86)mm/r
b) 按鉆頭強度決定進給量 根據(jù)表2.8，當бb=190MPa,do=18mm,鉆頭強度允許的進給量f=1.6mm/r
c)按機床進給機構(gòu)強度決定進給量 根據(jù)表2.9，當бb210MPa,do20.5mm,機床進給機構(gòu)允許的軸向力為11760N（Z535鉆床允許的軸向力為15696N（見《工藝設(shè)計手冊》表4.2-14）時，進給量為1.5mm/r。
從以上三個進給量比較可以看出，受限制的進給量是工藝要求，其值為f=0.70~0.86mm/r，根據(jù)Z535鉆床說明書，選f=0.80mm/r（見《工藝設(shè)計手冊》表4.2-16），又由《切削手冊》表2.19可以查出鉆孔時的軸向力，當f=0.80mm/r do<=21mm時，軸向力Ff=7260N
軸向力的修正系數(shù)為1.0，故Ff=7260N
根據(jù)Z535鉆床說明書，機床進給機構(gòu)強度允許的最大軸向力為Fmax=15696N，由于Ff
Mc
又根據(jù)《切削手冊》表2.23，當бb=(170~213)MPa do<=20mm f<=0.9mm/r vc<=17.4m/min時 Pc=1.7KW
根據(jù)Z535鉆床說明書, Pc Mc
又根據(jù)《切削手冊》表2.23，當бb=(170~213)MPa do<=20mm f<=0.75mm/r vc<=20m/min時 Pc=1.7KW
根據(jù)Z535鉆床說明書, Pc Mc
又根據(jù)《切削手冊》表2.23，當бb=(170~213)MPa do<=20mm f<=2.0mm/r vc<=10m/min時 Pc=1.7KW
根據(jù)Z535鉆床說明書, Pc3,故取修正系數(shù)K=0.8
所以 f=(0.18~0.22)x0.8=(0.144~0.176) mm/r
b) 按鉆頭強度決定進給量 根據(jù)表2.8，當бb=190MPa,do<=4.3mm,鉆頭強度允許的進給量f=0.5mm/r c)按機床進給機構(gòu)強度決定進給量 根據(jù)表2.9，當бb210MPa,do10.2mm,機床進給機構(gòu)允許的軸向力為8330N（Z525鉆床允許的軸向力為8830N（見《工藝設(shè)計手冊》表4.2-14）時，進給量為1.63mm/r。
從以上三個進給量比較可以看出，受限制的進給量是工藝要求，其值為f=(0.144~0.176) mm/r，根據(jù)Z525鉆床說明書，選f=0.17mm/r（見《工藝設(shè)計手冊》表4.2-16），又由《切削手冊》表2.19可以查出鉆孔時的軸向力，當f<=0.17mm/r do<=12mm時，軸向力Ff=1230N
軸向力的修正系數(shù)為1.0，故Ff=1230N
根據(jù)Z525鉆床說明書，機床進給機構(gòu)強度允許的最大軸向力為Fmax=8330N，由于Ff Mc
又根據(jù)《切削手冊》表2.23，當бb=(170~213)MPa do<=10mm f<=0.53mm/r vc<=17.4m/min時 Pc=0.8KW
根據(jù)Z525鉆床說明書, Pc
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