汽車發(fā)動機連桿大小頭孔中心線平行度自動檢測裝置設(shè)計

1、目錄中文摘要·················································

2、························4Absrtact························

3、83;·················································4第1

4、章 緒論·················································&#

5、183;···················51.1 課題的概況及提出····························&

6、#183;·······························51.2 課題分析················

7、3;·················································

8、3;·5第2章 總體方案設(shè)計···············································

9、;··············52.1 本裝置的主要組成部分·································&#

10、183;······················52.1.1 機械部分·························

11、83;·····································52.1.2 液壓部分··········

12、3;·················································

13、3;··52.1.3 電氣部分··············································

14、;·················52.2 本測試系統(tǒng)的理論方法和依據(jù)······························

15、;····················52.3 機械部分的作用及其設(shè)計原則···························

16、;·······················62.4 液壓部分的功能·························

17、;·····································62.5 模數(shù)轉(zhuǎn)換電路···········

18、··················································

19、···62.6 相關(guān)的計算機接口電路············································

20、83;···········6第3章機械部分的設(shè)計····································

21、3;······················63.1 傳感器的選用及安裝·························&#

22、183;································6 傳感器的選用················

23、··········································63.1.2 傳感器的安裝······

24、;··················································

25、;··63.1.2.1 測桿與外伸軸的剛度估計············································

26、83;·63.1.2.2傳感器的定位與安裝·············································

27、3;····73.2其他運動部件的設(shè)計與計算···········································

28、·········7 承載工作臺外形尺寸與重量估計······································&#

29、183;···7 測試箱外形尺寸及重量估算············································

30、··73.2.3 滾珠絲杠螺母副的設(shè)計計算·············································

31、;·73.2.3.1計算載荷FC（N）的計算·············································

32、83;·73.2.3.2計算額定動載荷計算值·············································73.

33、2.3.3根據(jù)選擇滾珠絲杠副···············································83.2

34、.3.4 穩(wěn)定性驗算················································&#

35、183;··········83.2.3.5 剛度驗算·····································&

36、#183;·······················83.2.4滾動導(dǎo)軌的設(shè)計························

37、·································93.2.4.1導(dǎo)軌的長度···············

38、;············································93.2.4.2滾動體尺寸與數(shù)目的確定··

39、3;············································93.2.4.3驗算許用負載···&#

40、183;·················································&#

41、183;···9 步進電機的選用·············································

42、;············93.2.5.1滾珠絲杠傳動系統(tǒng)傳動比i的確定··································

43、·····9.2減速齒輪的設(shè)計···········································&#

44、183;···········9.3 步進電機啟動力矩的計算····································

45、;···········93.2.5.4步進電機轉(zhuǎn)動慣量計算····································

46、;············10.5選擇步進電機的型號···································

47、3;··············103.3 數(shù)控系統(tǒng)的精度驗算·································&

48、#183;·······················10第4章液壓部分的設(shè)計························&

49、#183;·································104.1液壓缸的設(shè)計··············&#

50、183;················································114.1.1夾

51、緊力的計算·················································&

52、#183;·······114.1.2 確定液壓缸的主要尺寸·······································&

53、#183;·········114.1.3 計算液壓缸工作階段所需的流量····································

54、83;····114.1.4 液壓缸的安裝···········································&

55、#183;·············114.2液壓泵的選用··································&#

56、183;····························124.2.1泵的工作壓力的確定··················

57、3;································12 泵的流量確定················&

58、#183;········································124.2.3 選擇液壓泵的規(guī)格······

59、83;··············································124.3與液壓泵匹配電動機的選定

60、3;·················································

61、3;12第5章檢測裝置的數(shù)控系統(tǒng)硬件電路設(shè)計··········································135.1硬件電路總體設(shè)計方案··

62、;··················································

63、;···135.1.1 硬件電路框圖表示············································&

64、#183;········13 硬件電路主要元器件的選擇清單······································&#

65、183;··135.2主控制器CPU的選擇及其引腳············································&

66、#183;····135.2.1CPU的選擇···········································

67、·················135.2.28031的硬件資源及其引腳·····························

68、3;·················148031的內(nèi)部資源·······························

69、;······················145.2.2.28031的引腳定義及功能························&#

70、183;······················145.3 存儲器擴展電路的設(shè)計························

71、3;······························145.3.1程序存儲器的擴展電路芯片················

72、83;·····························145.3.2 地址鎖存器選用··················

73、······································145.3.3 數(shù)據(jù)存儲器的擴展電路芯片········

74、3;·····································155.3.4譯碼器的選用··········

75、83;···············································155.4I/O擴展電路的設(shè)計

76、··················································

77、·········155.4.18255可編程接口芯片的選用·····································

78、83;········155.4.1.1數(shù)據(jù)總線·······································&#

79、183;····················155.4.1.2控制線···························&#

80、183;··································155.4.1.3尋址線·············&#

81、183;················································165.4.2

82、步進電機驅(qū)動電路················································

83、3;·····165.4.2.1計算機接口··········································&#

84、183;···············165.4.2.2脈沖分配器································

85、··························165.4.2.3光電隔離電路·····················

86、83;··································165.4.2.4功率放大器·············&

87、#183;············································165.4.3三相異步電機的驅(qū)動電路··&

88、#183;·············································175.4.4電磁換向閥的驅(qū)動電路·&#

89、183;················································175.5模數(shù)轉(zhuǎn)

90、換電路設(shè)計·················································&

91、#183;··········175.5.1測量電橋·····································&#

92、183;························175.5.2 測量放大電路·······················

93、···································175.5.3相敏檢波電路·············

94、;············································175.5.4 功率放大電路···

95、83;·················································

96、83;···175.5.5集成采樣保持電路············································

97、·········185.5.6 A/D轉(zhuǎn)換電路······································

98、83;···················185.6其他輔助電路設(shè)計····························&#

99、183;······························18 5.6.1 鍵盤與顯示器接口電路················&

100、#183;································185.6.2 打印機接口電路··············

101、3;········································195.6.3 報警顯示接口電路·······

102、··············································19第6章控制軟件編程··&

103、#183;·················································&

104、#183;·······196.1監(jiān)控軟件的功能········································&

105、#183;····················196.1.1 儀表硬件和軟件的初始化··························

106、······················196.1.2基本輸入和輸出系統(tǒng)的實現(xiàn)·························

107、;·····················196.1.3儀表內(nèi)部的組態(tài)··························

108、83;·····························196.1.4 儀表的任調(diào)度··················&

109、#183;·······································196.2鍵盤與顯示器接口的軟件設(shè)計·······&

110、#183;·········································19 接口電路·······

111、··················································

112、····206.2.2 軟件設(shè)計············································

113、·················20鳴謝································&#

114、183;·········································23參考文獻·······&#

115、183;·················································&#

116、183;··············24汽車發(fā)動機連桿大小頭孔中心線平行度自動檢測裝置設(shè)計第1章 緒論1.1 課題的概況及提出精密測量技術(shù)是機械工業(yè)發(fā)展的基礎(chǔ)和先決條件之一，這已被生產(chǎn)發(fā)展的歷史所確認。從生產(chǎn)發(fā)展的歷史來看，精密加工精度的提高總是與精密測量技術(shù)的發(fā)展水平相關(guān)的。有人認為材料、精密加工、精密測量與控制是現(xiàn)代精密工程的三大支柱。對于科學(xué)技術(shù)來說，測量與控制是使其發(fā)展的促進因素，測量的精度和效率在一定程度上決定著科學(xué)技術(shù)的水平。目前，國外量儀已與

117、計算機技術(shù)和光電技術(shù)相結(jié)合，實現(xiàn)了自動化、數(shù)字化和多功能化，國內(nèi)也正朝著這個方向發(fā)展。近年來隨著汽車工業(yè)的飛速發(fā)展，人們對汽車發(fā)動機的性能要求越來越高。而連桿是發(fā)動機中的關(guān)鍵部件之一，其大、小頭孔中心線的平行度必須達到一定的精度，否則會導(dǎo)致發(fā)動機耗油量大，磨擦大，噪音大。因此設(shè)計一套自動化程度和測量精度高的專用于測量連桿大、小頭孔的測量裝置，是保證產(chǎn)品質(zhì)量和提高生產(chǎn)效率的重要手段。1.2 課題分析這里要測量的工件是某汽車發(fā)動機的連桿大、小頭孔中心線的平行度。本人去年在東風(fēng)汽車發(fā)動機廠的連桿加工車間實習(xí)時曾記得這一工序是通過氣壓量儀來測量的，即利用直徑對氣體的壓力而通過儀表進行顯示。這樣的測量裝

118、置還是能滿足精度要求的，但其靈敏度不是特別高，也難以適應(yīng)現(xiàn)代化的自動生產(chǎn)線。本測量系統(tǒng)的總體設(shè)計思想是：整個測量過程實現(xiàn)自動化，而不需人工干預(yù)。在本裝置中，采用滾珠絲杠以實現(xiàn)測桿的X方向的進給，工件的夾緊采用液壓油缸來保證系統(tǒng)的平穩(wěn)性，而自動檢測裝置選用應(yīng)用廣泛的8031單片機來實現(xiàn)對整個測試系統(tǒng)控制。第2章 總體方案設(shè)計2.1 本裝置的主要組成部分2.1.1 機械部分由傳感器箱體即測試箱、 X向數(shù)控工作臺、工件定位和夾緊部件組成。2.1.2 液壓部分由液壓泵、液壓缸和液壓控制閥組成。2.1.3 電氣部分包括CPU的選擇、存儲器擴展電路、I/O擴展電路、數(shù)模轉(zhuǎn)換電路、測量放大和信號采集保持電路

119、及其它輔助電路的設(shè)計。2.2 本測試系統(tǒng)的理論方法和依據(jù)在本測試系統(tǒng)中，測量連桿大小頭孔中心線的平行度所應(yīng)用的理論依據(jù)是運用數(shù)學(xué)方法：在每個孔的圓柱面內(nèi)側(cè)分別測出兩個截面上三個點的位置，根據(jù)這三個點確定一圓心，兩個圓心構(gòu)成一直線，再依據(jù)數(shù)學(xué)方法來計算這兩條直線的夾角，最后轉(zhuǎn)換成平行度。根據(jù)所測連桿大、小頭孔平行度誤差水平方向不大于100：0.03、垂直方向不大于100：0.06，而連桿總成裝配圖中要求以大頭孔的中心線為基準來測大、小頭孔中心線平行度，所以本測試系統(tǒng)就以一定位銷來確定大頭孔中心線的位置，只需測小頭孔中心線的位置最終則可轉(zhuǎn)換為其平行度。2.3 機械部分的作用及其設(shè)計原則測試箱主要是

120、將所選用的傳感器正確的定位與夾緊，其定位精度應(yīng)比檢測裝置的檢測精度高1個等級。測試箱由滾珠絲杠來拖動以實現(xiàn)X向的進給，關(guān)于滾珠絲杠的傳動部分設(shè)計原來已在機電綜合課程設(shè)計中詳細設(shè)計過，這里就簡要描述了。另外，連桿的定位精度和夾緊的可靠性要求也很高。2.4 液壓部分的功能在進行測試前，應(yīng)保證工件的正確定位和夾緊，而本裝置屬于精密測量儀器，系統(tǒng)在運行過程中要求振動小，而液壓系統(tǒng)具有平穩(wěn)性好，運動慣性小、反應(yīng)速度快、易于實現(xiàn)自動化控制等優(yōu)點。因此，在本系統(tǒng)中運用液壓系統(tǒng)對工作進行夾緊比較理想。2.5 模數(shù)轉(zhuǎn)換電路在實際測量中，由于傳感器的輸出量是連續(xù)變化的物理量，也就是模擬量，與此對應(yīng)的電信號則是模擬

121、信號，要將其輸入計算機進行數(shù)據(jù)處理，就需要運用A/D轉(zhuǎn)換電路將模擬信號轉(zhuǎn)換為計算機可識別的數(shù)字信號，其轉(zhuǎn)換過程主要包括采樣、量化和編碼。這里采用逐次逼近式的轉(zhuǎn)換電路，因逼近式A/D轉(zhuǎn)換器在精度、速度和價格上都適中，是目前最常用的A、D轉(zhuǎn)換器。具體設(shè)計見后面。2.6 相關(guān)的計算機接口電路因本系統(tǒng)屬于工業(yè)測控的智能化儀器儀表，根據(jù)實際需要，在這里需要解決計算機和外設(shè)聯(lián)系的接口電路，包括鍵盤、顯示器和打印機。第3章 機械部分的設(shè)計3.1 傳感器的選用與安裝 傳感器的選用本檢測裝置選用差動變壓器式位移傳感器。因差動變壓器式傳感器應(yīng)用比較廣泛，其靈敏度高，精確度高，非線性誤差小，量程較寬，適合本系統(tǒng)，現(xiàn)

122、選用的傳感器為中原量儀股份有限公司生產(chǎn)的DG-z7型（軸式）差動變壓器式傳感器。其主要性能規(guī)格示值為：變動性：0.2um測量力：0.40.7N總行程：1.2mm裝卡尺寸：F8h7外形尺寸：F8´30重量：0.15N3.1.2 傳感器的安裝3.1.2.1 測桿與外伸軸的剛度估計因所測的連桿小頭孔的直徑只有28mm，無法使傳感器直接安裝在所測孔的內(nèi)表面上，這里考慮選用一個杠桿機構(gòu)，稱之為測桿。它的一端安裝一個測頭，另一端與傳感器的測頭相接觸，同時這個機構(gòu)還可以將這杠桿孔的直徑誤差進行放大，以保證整個測試系統(tǒng)的測量精度。整個系統(tǒng)設(shè)計出三個測桿，它們安裝在測試箱的外伸軸上。由于所測的連桿小頭

123、孔的直徑誤差很小，必須考慮測試桿和外伸軸的剛度，避免因變形而影響整個測試系統(tǒng)的精度。為了降低測桿變形，在安裝時除了采用支承銷時還另加彈簧，因在測試過程中，測頭所受到的測量力非常小，再加上自身重量還不足1N，而測桿的材料是選用優(yōu)質(zhì)的45鋼，承受這樣小的力，估計其變形可以忽略，因而無需校核其剛度。此外，因外伸軸的外伸長度只有123mm,最小直徑12.5mm，材料同樣選用45鋼，同樣可以忽略其變形。3.1.2.2 傳感器的定位與安裝傳感器的安裝與定位在本測試裝置的設(shè)計中屬于一個重點問題，因它的正確定位直接影響到測試系統(tǒng)的精度。但它所帶來的誤差屬于常值系統(tǒng)誤差，可以通過計算機的編程等方法來予以補償。傳

124、感器在安裝后可以通過調(diào)整與其相連的壓板螺母來調(diào)節(jié)其軸向定位和徑向定位精度。其詳細裝配情況見測試箱裝配圖及其三維圖。3.2 其他運動部件的設(shè)計與計算 承載工作臺外形尺寸與重量估計 G工作臺=(200´140´60´10-3)cm3´(7.8´10-3)kg/cm3´10N/kg=131N 測試箱外形尺寸及重量估算G外伸軸=(3.14´132´190´10-3) cm3´(7.8´10-3 )kg/cm3´10N/kg=7.86NG測試箱=(100´160´1

125、60´10-3 )cm3´(7.8´10-3 )kg/cm3´10N/kg ´2/3=133.12NG傳感器=0.15N´3=0.45NG總= G工作臺+G外伸軸+G測試箱+G傳感器=272.43N3.2.3 滾珠絲杠螺母副的設(shè)計計算3.2.3.1 計算載荷FC（N）的計算FC=KFKHKAFm 式中，KF載荷系數(shù)，取KF=1.2；KH硬度系數(shù)，取KH=1.0；KA精度系數(shù)，設(shè)計為3級精度，取KA=1.1；Fm為平均工作載荷，取Fm=1.414fBG總=1.414´0.01´272.43N=4N FC=1.2

126、80;1.0´1.1´4N=5.28N .2 計算額定動載荷計算值= FC 式中，為滾珠絲杠的平均轉(zhuǎn)速（r/min）, =1000v/L0,其中v為最大工作載荷下的進給速度,取v=1m/min.L0為滾珠絲杠的基本導(dǎo)程(mm),這里初定為5mm.則=1000´1/5=200r/min; 為使用壽命，取=15000h =30N .3 根據(jù)選擇滾珠絲杠副根據(jù)最大動載荷并考慮各種因素，選擇滾珠絲杠副的幾何參數(shù)以下：公稱直徑：D0=20mm導(dǎo)程：p=5mm螺旋角：=4°33滾珠直徑：Dw=3.175mm滾道半徑：R=0.52Dw=0.52´3.175m

127、m=1.651mm偏心距：e=0.07(R-Dw/2)=0.707´(1.651-3.175/2)mm=4.5´10-2mm絲杠內(nèi)徑：d1=D0+2e-2R=(20+2´4.5´10-2-2´1.651)mm=16.788mm3.2.3.4 穩(wěn)定性驗算絲杠不會發(fā)生失穩(wěn)的最大載荷為Fcr= 式中，E絲杠材料的彈性模量，取E=206GPa； 絲杠的工作長度(m)，這里0.28m; 絲杠危險截面軸慣性矩(m4)， =d14/64=3.14´(0.016788m)4/64=3´10-8m4 長度系數(shù)，設(shè)計絲杠的支承方式為一端固定，一

128、端游動，故取2/3 Fcr=1.74´106N安全系數(shù)S= Fcr/Fm=1.74´106/4=435000,可見足夠安全，不會失穩(wěn)。3.2.3.5 剛度驗算絲杠的拉壓變形量為 1=±Fm/EA,得1=±4´280/20.6´104´255=±0.3´10-4mm,滾珠與螺紋滾道間的接觸變形量2，該變形量與滾珠列、圈有關(guān)，即與滾珠總數(shù)有關(guān)，與滾珠總數(shù)有關(guān)，與滾珠絲杠長度無關(guān)。有預(yù)緊時：2=0.0013´ 式中，預(yù)緊力(kgf), =0.673kgf； =´圈數(shù)´列數(shù)；代入有關(guān)

129、數(shù)據(jù)算得2=1.47´10-3mm.當(dāng)預(yù)緊力為軸向工作載荷的1/3時，2的值可減少一半左右，2=0.74´10-3mm =1+2=0.00077mm本系統(tǒng)的定位精度為0.015，可見滿足要求。取滾珠絲桿精度等級為3級，允差為12um所以也能符合設(shè)計要求。 滾動導(dǎo)軌的設(shè)計 由于雙V形滾動導(dǎo)軌結(jié)構(gòu)對稱，工作臺可以放在兩導(dǎo)軌之間，能承受側(cè)向力矩，接觸剛度好、導(dǎo)向性和精度保持性好，并設(shè)計為鑲條方便維修和調(diào)整，因此滿足設(shè)計要求。3.2.4.1 導(dǎo)軌的長度 根據(jù)測量過程中工作臺實際需要移動的距離，取導(dǎo)軌的總長度為240mm，則動導(dǎo)軌長度為140mm，動導(dǎo)軌行程為100mm，滾珠保持器的

130、長度為190mm. 滾動體尺寸與數(shù)目的確定 由于工作臺重量輕，并且在工作過程中動載荷只有4N。根據(jù)機床設(shè)計手冊中的雙V型導(dǎo)軌的滾動體的直徑最好不低于6mm，因為若滾動體太小就容易產(chǎn)生滑動象?，F(xiàn)選滾珠的直徑為6mm。滾動體數(shù)目選擇的根據(jù)：zG/30,算得z=10，由動導(dǎo)軌長度為140mm，得兩滾珠之間的距離t=14mm.3.2.4.3 驗算許用負載平均每個滾動體上的最大負載為：Pmax=PG/z，所以Pmax=15.412N，許用負載P=Kd2 式中，K滾動體截面上假想許用應(yīng)力，經(jīng)查表取K=60N/cm2;導(dǎo)軌硬度校正系數(shù),這里取=1。P=60´1´0.62N=21.6N這里

131、設(shè)計的導(dǎo)軌選用淬透鋼HRC=55，所以P=21.6N，Pmax=15.412NP可見，雙V型滾珠導(dǎo)規(guī)符合要求。 步進電機的選用 滾珠絲杠傳動系統(tǒng)傳動比i的確定i=bL0/360p式中，b電動機步距角（°）/脈沖，初定b=1.5°/脈沖;L0滾珠絲杠導(dǎo)程（mm），取L0=5mm;p脈沖當(dāng)量（mm/脈沖）,這里根據(jù)系統(tǒng)精度要求取p =0.01 mm/脈沖i=1.5´5/360´0.01=2.08.2 減速齒輪的設(shè)計 由i=2.08要求在傳動系統(tǒng)中加一對減速齒輪。根據(jù)i=Z2/Z1=2.08,現(xiàn)取Z2=50，Z1=24。由于絲杠在工作過程中所愛的傳動扭矩很小，

132、取模數(shù)m=1，齒輪的具體參數(shù)設(shè)計如下：齒輪1：Z=24,d=24,b=4齒輪2：Z=50，d=50,b=6中心距：a=37Z齒數(shù)；d齒輪的公稱直徑(mm);b齒輪寬度(mm);a兩個齒輪的中心距(mm).3 步進電機啟動力矩的計算設(shè)步進電機的等效負載力矩為T，負載為P，根據(jù)能量守恒定理，電機所做的功與負載所做的功有如下關(guān)系：T=PS式中，電機轉(zhuǎn)角；S移動部件的相對位移；機械傳動效率； 步進電機的最高工作頻率：fmax=1000Vmax/60p=1667Hz 步進電機轉(zhuǎn)動慣量計算Jd=J0+J1+(Z1/Z2)2(J2+J3)+m(p ´180/3.14b)2 對材料為鋼的圓柱零件轉(zhuǎn)動

133、慣量可按下式計算：J=0.78´10-3´D4´L 式中，D圓柱零件的直徑(cm)；L零件長度（cm）.J1=0.78´10-3´2.44´0.25=19.24´10-2 kg.cm2J2=0.78´10-3´54´0.5=24.375´10-2 kg.cm2J3=0.78´10-3´2.64´26=32.45´10-2 kg.cm2J0很小可以忽略為0 Jd=1.294´10-2+(24.375+32.45) ´10-2+5

134、1´ (0.001´180/3.14´1.5)2 =0.218 kg.cm2Wmax=2´3.14´fmax=43.62 rad/sTg=Jd ´ (Wmax-W0)/0.01=9.51 N.cmJmax>Tg/k=Tg/0.5=19.02 N.cm .5 選擇步進電機的型號根據(jù)最大的靜轉(zhuǎn)矩Jmax=19.02 N.cm,選反應(yīng)式步進電動機45BF005.有關(guān)參數(shù)見表3-1。表3-145BF005步進電機參數(shù)外徑 長度 軸徑質(zhì)量 步距角 電壓 相電流 最高啟動空載頻率 最大靜轉(zhuǎn)矩(mm) (mm) (mm) (kg) （

135、6;）/脈沖 (v) (A) (Hz）(N·m)45 58 4 0.4 1.5 27 2.5 3000 0.1963.3 數(shù)控系統(tǒng)的精度驗算 步進電機驅(qū)動的數(shù)控系統(tǒng)精度可以不用驗算，因為測量前兩面的工作臺的定位精度要求并不十分嚴格，而數(shù)控系統(tǒng)本身的精度已能滿足要求，特別是滾珠絲杠螺母副的采用，具有傳動效率高，摩擦小，采用經(jīng)齒差調(diào)隙式的雙螺母預(yù)緊方式，經(jīng)適當(dāng)預(yù)緊后，可消除絲杠和螺母的間隙，定位精度高，剛度好，運動平穩(wěn)，傳動精度高，精度保持性好，使用壽命長。而減速齒輪的間隙在設(shè)計時采用了偏心套消除間隙，這樣可以使傳動更平穩(wěn)，并能消振。第4章 液壓部分的設(shè)計在本系統(tǒng)中，液壓傳動裝置的作用是

136、夾緊工件，其設(shè)計的依據(jù)是盡可能使工件夾緊，并定位準確?？紤]到夾緊時間可調(diào)節(jié)和當(dāng)進油路壓力瞬時下降時保持夾緊力，所以接入節(jié)流閥調(diào)速和單向閥保壓。在回路上加上減壓閥，用來調(diào)節(jié)夾緊力的大小和保持夾緊力的穩(wěn)定?？傮w設(shè)計方案如圖4-1所示。圖4-1液壓夾緊回路系統(tǒng)圖4.1 液壓缸的設(shè)計4.1.1 夾緊力的計算根據(jù)經(jīng)驗，取夾緊力為工件重量的三倍。由連桿總成圖算得工件重量如下：G工件=(190+50+26) ´152/2´38´7.8´10-5=59N F夾=3 G工件=3´59=177N4.1.2 確定液壓缸的主要尺寸取液壓系統(tǒng)的機械效率為0.95，夾緊液

137、壓缸的輸工作壓力p1為2.5MPa，回油背壓力p2為0，即可得液壓缸內(nèi)徑D的面積為D=0.032m=32mm 查表確定液壓缸和活塞桿的D和d分別為40mm及25mm.4.1.3 計算液壓缸工作階段所需的流量 設(shè)v夾=2m/min,工作階段所需的流量為q夾=D2v夾/4=(/4) ´0.042´2m3/min=5.25L/min 按照q夾選擇液壓系統(tǒng)中的各元件型號，具體型號與安裝見總裝配圖。4.1.4 液壓缸的安裝液壓缸的安裝方式采用中部法蘭聯(lián)接，即設(shè)計為支座，由于液壓缸與底座相平行，所以底座應(yīng)設(shè)計成帶有直角形狀，具體結(jié)構(gòu)與參數(shù)見支座零件圖。4.2 液壓泵的選用4.2.1 泵的工作壓力的確定考慮到正常工作中進油管路有一定的壓力損失，所以泵的工作壓力為pp=p1+p式中，pp液壓泵最大工作壓力；p1執(zhí)行元件最大工作壓力；p進油管路中的壓力損失，這里取0.3MPa. pp =(2.5+0.3)MPa=2.8MPa 泵的流量確定qp=KL(q)max 式中，qp液壓泵最大流量；(q)max執(zhí)行元件所需流量之和的最大值,這里取6L/min；KL系統(tǒng)泄漏系數(shù)，一般取1.11.3，現(xiàn)取KL=1.2 qp=1.2´6=7.2L/min4.2.3 選擇液壓泵的規(guī)格根據(jù)以上算得的pp