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摘 要
鏜床液壓站的設(shè)計(jì)，在保證機(jī)械成功運(yùn)轉(zhuǎn)時(shí)，還需要注意機(jī)器的實(shí)用性能，機(jī)器要滿足性價(jià)比高，效率高，操作便利，維修便利和使用壽命長(zhǎng)等一些實(shí)際生產(chǎn)使用的原則。我們由題目確定的條件，通過計(jì)算選取合適的液壓元件和系統(tǒng)。首先對(duì)液壓原理圖進(jìn)行分析，得到完整的回路，選取合適的元件進(jìn)行組裝。
最后對(duì)液壓站整體進(jìn)行校核，參考實(shí)際工作的使用標(biāo)準(zhǔn)，對(duì)元件再次進(jìn)行考核和篩選，最終對(duì)整個(gè)液壓站進(jìn)行校核，看整體是否滿足液壓站的使用標(biāo)準(zhǔn)。
關(guān)鍵詞：專用鏜床 液壓回路 液壓傳動(dòng) 電磁換向閥 液壓站
Ⅲ
Abstract
壓縮包內(nèi)含有CAD圖紙和說明書,咨詢Q 197216396 或 11970985
Abstract
Boring hydraulic station design, to ensure the successful operation of machinery, you also need to pay attention to the practical performance of the machine, the machine to meet the high cost, high efficiency, convenient operation, maintenance and use of the actual production of some of the principles of convenience and long life. We made subject conditions determined by calculating select the appropriate hydraulic components and systems. First hydraulic schematic diagram is analyzed to obtain a complete loop, select the appropriate components for assembly.
Finally, the overall hydraulic station to be checked using a standard reference the actual work on the elements again screening and assessment, and ultimately the entire hydraulic station to be checked to see whether the overall requirements of the hydraulic station using standard.
Key words: Boring machine Hydraulic circuit Hydraulic transmission Solenoid valve Hydraulic station
目 錄
摘 要．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．III
Abstract．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．Ⅳ
第一章 前 言．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．1
1.1鏜床概述．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．1
1.2 液壓傳動(dòng)概述．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２
1.2.1 液壓傳動(dòng)原理及系統(tǒng)組成．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２
1.2.2 液壓傳動(dòng)優(yōu)缺．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２
1.3本課題意義．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．３
1.4 液壓系統(tǒng)設(shè)計(jì)主要參數(shù)及要求．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．３
第二章 液壓系統(tǒng)工況分析．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．４
2.1負(fù)載計(jì)算及分析．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．４
2.2 液壓站系統(tǒng)參數(shù)計(jì)算．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．６
2.2.1由壓力值選取液壓缸．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．６
2.2.2 計(jì)算液壓缸主要尺寸．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．６
第三章 液壓系統(tǒng)回路選擇．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１０
3.1 選取工作泵．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１０
3.2 動(dòng)作實(shí)現(xiàn)及基本回路選擇．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１０
3.2.1 調(diào)速回路．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１０
3.2.2控制閥選擇．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１０
3.2.3 壓力繼電器和行程開關(guān)的確認(rèn)．．．．．．．．．．．．．．．．．．．．．．．．．．．．１１
3.2.4溢流閥的確認(rèn)．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１１
3.3 原理圖．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１２
第四章 液壓站元件確認(rèn)．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１５
4.1選取液壓泵．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１５
4.1.1 液壓泵工作壓力理論值．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１５
4.1.2 液壓泵理論流量．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１５
4.2電動(dòng)機(jī)額定功率．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１５
選取液壓站元件．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１６
4.3.1確定控制元件．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１６
4.3.2 明確油路連接．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１７
4.3.3選取油箱規(guī)格．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１８
第五章 液壓站整體校核．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１９
5.1校核系統(tǒng)壓力值．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１９
5.1.1夾緊缸工作過程校核．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．１９
5.1.2進(jìn)給缸工作過程校核．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２０
5.2校核散熱系統(tǒng)．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２１
第六章 總結(jié)．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２３
參 考 文 獻(xiàn)．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．２４
XII
Abstract
摘要
第一章 前言
第一章 前 言
1.1鏜床概述
鏜床，一種常用的工廠機(jī)床設(shè)備，其工作原理是通過機(jī)床工進(jìn)、快進(jìn)和快退對(duì)需要進(jìn)行孔加工的工件進(jìn)行加工。鏜床是在現(xiàn)在實(shí)際工作使用中經(jīng)常使用的一種機(jī)床，鏜床可以進(jìn)行大型零件的加工，隨著社會(huì)的不斷進(jìn)步，實(shí)際生產(chǎn)過程中的工件要求逐步提高，鏜床已經(jīng)逐步在取代鉆床在實(shí)際應(yīng)用中的地位。鏜床由于大范圍的使用，也開始進(jìn)行逐步的發(fā)展，在實(shí)際工作中，鏜床可以切換不同的刀具對(duì)工件進(jìn)行不同形式的加工，因此鏜床可以進(jìn)行不同的工作如：螺紋孔加工、平面加工、槽渠的加工等。鏜床進(jìn)行加工時(shí)，我們保持工件加緊，使其保持穩(wěn)定不動(dòng)，使刀具的中心與工件的中心在一條水平線上，刀具進(jìn)行工進(jìn)、快進(jìn)和快退來進(jìn)行加工。
遠(yuǎn)在15世紀(jì)，隨著殖民主義在世界范圍的不斷擴(kuò)張，為了滿足戰(zhàn)爭(zhēng)的需要，開始大量制造武器，在當(dāng)時(shí)就已經(jīng)研制出炮筒鏜床，炮筒鏜床當(dāng)時(shí)是通過水利驅(qū)動(dòng)的，動(dòng)力系統(tǒng)使用具有明顯的地域限制，但是在當(dāng)時(shí)已經(jīng)是科技發(fā)展的一大進(jìn)步。隨著18世紀(jì)瓦特成功研制出來蒸汽機(jī)之后，動(dòng)力系統(tǒng)的使用得到了很大的改善，但是另外一個(gè)問題又?jǐn)[在人們面前，原先的炮筒鏜床的工作已經(jīng)不能滿足工件加工的精度要求。在之后的10年之內(nèi)，富有創(chuàng)造力的歐洲人又研制出了，以瓦特蒸汽機(jī)為動(dòng)力系統(tǒng)，并且加工工件精密度較高的氣缸鏜床，這在當(dāng)時(shí)引起了不小的轟動(dòng)。時(shí)間到達(dá)了19世紀(jì)，資本主義國(guó)家開始發(fā)展重工業(yè)，為了滿足特大型工件的加工，臥式鏜床應(yīng)運(yùn)而生。隨著第一次世界大戰(zhàn)落幕，各國(guó)大力發(fā)展重工業(yè)，各種工件的加工量迅速增加，因此人們又研發(fā)出了落地式機(jī)床。到了21世紀(jì)，隨著光學(xué)和數(shù)學(xué)等其他領(lǐng)域的不斷突破，加上人們對(duì)生活品質(zhì)的不斷追求，工件的精密度要求越來越苛刻，鏜床已逐步走向激光定位以及數(shù)控機(jī)床，實(shí)習(xí)工件加工從頭到尾一體化和全自動(dòng)化。
近五十年來，在工業(yè)中有兩個(gè)學(xué)科分支發(fā)展極快。其一是電子學(xué)中的計(jì)算機(jī)技術(shù)；其二是機(jī)械學(xué)中的液壓控制與傳動(dòng)技術(shù)。這兩門技術(shù)互相滲透和融合，是現(xiàn)代機(jī)械的設(shè)計(jì)、制造和使用突飛猛進(jìn)。
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1.2 液壓傳動(dòng)概述
翻閱資料我們可以了解到，目前在機(jī)械領(lǐng)域中，液壓傳動(dòng)技術(shù)是發(fā)展較為成熟的一種技術(shù)手段。尤其是隨著這些年來，光學(xué)、數(shù)學(xué)和計(jì)算機(jī)學(xué)等領(lǐng)域的不斷突破，與液壓學(xué)相結(jié)合，使得液壓傳動(dòng)裝置也在不斷地提高。并且液壓傳動(dòng)裝置以其穩(wěn)定并且使用壽命和污染小等優(yōu)點(diǎn)在傳動(dòng)裝置中越來越突出。
1.2.1 液壓傳動(dòng)原理及系統(tǒng)組成
液壓工作原理相對(duì)比較簡(jiǎn)單，從字面上我們可以理解液壓傳動(dòng)的工作原理是通過液體對(duì)裝置產(chǎn)生壓力，利用這個(gè)壓力來推動(dòng)機(jī)床來進(jìn)行工作。
從理論上來說，一個(gè)完整的液壓系統(tǒng)需要具備以下幾個(gè)部分，首先需要具有產(chǎn)生壓力的液體，為系統(tǒng)提供傳動(dòng)能量；然后需要將原有的機(jī)械能和壓力互相轉(zhuǎn)換的動(dòng)力和執(zhí)行元件； 最為關(guān)鍵的是在系統(tǒng)中起到調(diào)節(jié)和控制的控制元件；當(dāng)然一些輔助元件也是必不可少的。
1.2.2 液壓傳動(dòng)優(yōu)缺點(diǎn)
液壓系統(tǒng)優(yōu)缺點(diǎn)明顯，其中優(yōu)點(diǎn)如下所示：
1.液壓傳動(dòng)裝置與其他傳動(dòng)裝置對(duì)比，在相同的情況下，液壓傳動(dòng)裝置穩(wěn)定性高，
污染小，操作便捷。
2.液壓傳動(dòng)裝置的元件已經(jīng)形成了一種標(biāo)準(zhǔn)，更為便于設(shè)計(jì)和使用，在實(shí)際生產(chǎn)中，
更加便于零件的補(bǔ)充和再利用。
3.液壓傳動(dòng)裝置能夠?qū)崿F(xiàn)系統(tǒng)的一體化和自動(dòng)化。
4.因?yàn)橐簤簜鲃?dòng)裝置的零件標(biāo)準(zhǔn)化，因此損壞的零件可以單獨(dú)進(jìn)行快速替換，提高
了機(jī)器的使用壽命。
反之，液壓傳動(dòng)也存在較多不足，其缺點(diǎn)如下：
1.液壓傳動(dòng)裝置由于是靠液體產(chǎn)生壓力，顧此對(duì)機(jī)器的密封程度要求很高，很容易
出現(xiàn)液體的泄露導(dǎo)致機(jī)器壓力不夠的問題。
2.如上所說，因?yàn)橐簤簜鲃?dòng)裝置是通過液體產(chǎn)生壓力，故此對(duì)環(huán)境也有一定的要求，
如果外界溫度過低，會(huì)引起液體不能提供良好的傳動(dòng)作用。
3.當(dāng)液壓傳動(dòng)裝置出息液壓液體泄漏是，我們很難快速找到問題并解決。
1.3本課題意義
本課題具有如下幾點(diǎn)意義：
1.讓我們將平時(shí)所學(xué)到的知識(shí)運(yùn)用到實(shí)際工作當(dāng)中去，通過不斷的實(shí)踐，來將課本上的知識(shí)進(jìn)一步消化和吸收。
2.更加方便的與指導(dǎo)老師溝通，明確的認(rèn)知到自身的不足，在老師的指點(diǎn)下不斷學(xué)習(xí)相關(guān)專業(yè)知識(shí)，提升自己。
3.提高CAD繪圖的能力，提高自身
4. 提高撰寫設(shè)計(jì)說明書（論文）的能力。
5.提高自身論辯的能力，對(duì)自己設(shè)計(jì)的作品能夠進(jìn)行具體的說明，為之后的工作打下基礎(chǔ)。
1.4 液壓系統(tǒng)設(shè)計(jì)主要參數(shù)及要求
本課題主要是設(shè)計(jì)用于流水線上箱體內(nèi)孔加工的專用鏜床的液壓動(dòng)力系統(tǒng)。鏜床采用液壓進(jìn)給系統(tǒng)自動(dòng)化加工。機(jī)床加工過程的工作循環(huán)為：工件安裝夾緊到位，刀頭快速接近工件，工進(jìn)速度鏜削內(nèi)孔，加工到位停止，刀頭快速退回，其大致工作過程為：
定位—夾緊—快進(jìn)—工進(jìn)—快退—停止。
根據(jù)課題任務(wù)書得到主要設(shè)計(jì)參數(shù)及要求如下：
第二章 液壓系統(tǒng)工況分析
進(jìn)給刀頭及拖板最大行程500mm，最大加工進(jìn)給力12kN，最小進(jìn)給速度2 mm/s ，最大進(jìn)給速度不大于20 mm/s ，快進(jìn)速度60mm/s，快進(jìn)行程150 mm。要求保證加工質(zhì)量，自動(dòng)化，能效高，調(diào)速穩(wěn)定。
第二章 液壓系統(tǒng)工況分析
2.1負(fù)載計(jì)算及分析
根據(jù)任務(wù)書，夾緊力未知，故而根據(jù)實(shí)際工件進(jìn)給可能需要夾緊力取最大夾緊力為30KN，不考慮能量損失的情況下，則夾緊液壓缸工作負(fù)載：
，
很明顯實(shí)際工作中，能量存在損失，取的傳遞效率為取0.9，，根據(jù)公式：
考慮到實(shí)際工件的質(zhì)量不是很高，在計(jì)算過程中不做計(jì)算，因此可以計(jì)算出
由上式可知，快進(jìn)和快退的速度為：，，任務(wù)書沒有給出，考慮到進(jìn)給速度最大值為0.02m/s，取夾緊缸慢進(jìn)速度：?？紤]到工作的安全性，對(duì)于夾緊液壓用行程250mm；
查閱手冊(cè)等相關(guān)設(shè)計(jì)資料取最大切削力為120KN，故而進(jìn)給液壓缸理論工作負(fù)載
根據(jù)慣性負(fù)載公式：
我們按照之前選取的液壓缸的機(jī)械效率為0.9，計(jì)算出：
進(jìn)給油缸快進(jìn)、快退速度：，進(jìn)給油缸工進(jìn)速度最大為：，進(jìn)給缸行程最大為500mm。從計(jì)算結(jié)果可以得到以下兩張表格2-1和2-2.
表2-1 夾緊缸啟動(dòng)至快進(jìn)時(shí)負(fù)載F(N)
表2-2 進(jìn)給缸啟動(dòng)至快進(jìn)時(shí)負(fù)載F(N)
從以上兩張表格2-1和表格2-2可以的到負(fù)載圖：
夾緊缸負(fù)載圖 進(jìn)給缸負(fù)載圖
夾緊缸速度圖 進(jìn)給剛速度圖
2.2 液壓站系統(tǒng)參數(shù)計(jì)算
2.2.1由壓力值選取液壓缸
根據(jù)系統(tǒng)中夾緊油缸工作最大負(fù)載為，首先我們假設(shè)選取液壓缸的壓力是p1=4MPa。由從上表2-1可以看出，理論上來說當(dāng)進(jìn)給油缸開始工作時(shí)最大負(fù)載為，因此我們選取工作壓力為p1=8MPa。
表2-2選取工作壓力
2.2.2 計(jì)算液壓缸主要尺寸
根據(jù)公式可以得出 ，
因?yàn)? ， 故而
從上方公式可以得知，夾緊缸和進(jìn)給缸的工作面積是和 。
又因?yàn)?可以計(jì)算得出兩缸缸內(nèi)運(yùn)動(dòng)活塞的直徑：
，
根據(jù)公式可以得出 。，。
經(jīng)查閱，
，，
，。
又可以根據(jù)，計(jì)算得出兩缸實(shí)際工作時(shí)能夠產(chǎn)生工作效率的面積為：
，
，
經(jīng)過反復(fù)檢驗(yàn)，數(shù)據(jù)據(jù)符合相關(guān)要求。
圖2.3 進(jìn)給缸的工況圖
圖2.4夾緊缸的工況圖
表2.3夾緊缸在各階段的壓力、流量和功率值
表2.4進(jìn)給缸在各階段的壓力、流量和功率值
第二章 液壓系統(tǒng)工況分析
第三章 液壓系統(tǒng)回路分析
第三章 液壓系統(tǒng)回路選擇
床加工過程的工作循環(huán)為：工件安裝夾緊到位，刀頭快速接近工件，工進(jìn)速度鏜削內(nèi)孔，加工到位停止，刀頭快速退回，其大致工作循環(huán)過程為：
定位—夾緊—快進(jìn)—工進(jìn)—快退—停止
根據(jù)此循環(huán)過程選擇液壓回路實(shí)現(xiàn)各個(gè)動(dòng)作。
3.1 選取工作泵
在工作情況圖中我們可以知道，在工作過程中有兩個(gè)液壓缸進(jìn)行工作，所以要求油源分別提供不同行程的不同油液。兩缸的理論極限值的大小比較為， 。在工作前可根據(jù)實(shí)際加工的需要對(duì)最大行程進(jìn)行調(diào)節(jié)。對(duì)于本次設(shè)計(jì)的機(jī)床來說，液壓系統(tǒng)可以使用同一個(gè)泵來為不同的兩個(gè)油缸來服務(wù)，因此我們可以在限壓式變量泵和雙作用葉片泵中選取任意一個(gè)作為油源。這兩個(gè)泵都具有實(shí)現(xiàn)系統(tǒng)實(shí)際運(yùn)作的功能，然而我們最終選取雙作用葉片泵作為動(dòng)力，因?yàn)閺膶?shí)際角度出發(fā)考慮到雙作用葉片泵在實(shí)際工作中承受壓力較高并且便宜高效。
3.2 動(dòng)作實(shí)現(xiàn)及基本回路選擇
3.2.1 調(diào)速回路
3.2.2控制閥的選擇
思考到實(shí)際工作過程中液壓站內(nèi)部流量不小，系統(tǒng)中沒有選取電液換向閥來進(jìn)行換向回路，而是選取了電磁換向閥，然而其他地方則是選用了三位四通電液換向閥。
圖3-1三位四通電磁換向閥和三位四通電液換向閥
3.2.3 壓力繼電器和行程開關(guān)的確認(rèn)
從下圖中我們可以了解到，當(dāng)機(jī)床需要快退時(shí)，要給兩缸都發(fā)出快退信號(hào)，因此我們需要分別為兩缸設(shè)置壓力繼電器和行程開關(guān)。
圖3.2 快進(jìn)轉(zhuǎn)工進(jìn)功能實(shí)現(xiàn)
3.2.4溢流閥確認(rèn)
由于之前考慮到系統(tǒng)整體流量較大，故此我們沒有選用限壓式變量泵，而是選用了雙作用葉片泵，從這邊我們也可以了解到，我們需要為兩缸設(shè)置溢流閥來為系統(tǒng)調(diào)節(jié)整體壓力，又通過計(jì)算可以得知，兩缸不是同時(shí)進(jìn)行供油的，所以單個(gè)的溢流閥只對(duì)單個(gè)的油缸進(jìn)行負(fù)責(zé)。
圖3.3溢流閥
3.3原理圖
通過之前的計(jì)算我們可以基本確認(rèn)液壓站系統(tǒng)大致的整體結(jié)構(gòu)，我們?cè)偻ㄟ^查閱資料，選取合適的工作元件將整個(gè)液壓站系統(tǒng)組裝在一起，我們可以得到液壓站系統(tǒng)原理圖，最終我們可以通過液壓站原理圖來進(jìn)行圖紙的繪制以及工件的組裝，從原理圖中我們可以看出：
圖3-4原理圖
表3-1工作狀態(tài)表
第四章 液壓元件選型與計(jì)算
第四章 液壓站元件確認(rèn)
4.1選取液壓泵
4.1.1 液壓泵工作壓力理論值
從之前論述可以得知，進(jìn)給缸在工作是理論極限值為p1=8.09MPa，通過計(jì)算得出，液壓系統(tǒng)中的總壓力損失是∑?p=0.6MPa
通過公式可以計(jì)算出
4.1.2液壓泵理論流量
查看表格2-4可知，通過液壓液體向缸內(nèi)運(yùn)輸?shù)牧髁孔畲笫?.136×10-3 m3/s ，查閱資料選取K=1.1，
在實(shí)際工作中，我們還必須要注意其他元件的工作狀態(tài)，在之前的論述中，我們確認(rèn)了溢流閥流量為3L/min，那么我們可以清楚地知道系統(tǒng)總的流量，因此，我們最終選擇雙作用葉片泵：
則我們可以通過以上數(shù)據(jù)計(jì)算出：。
4.2電動(dòng)機(jī)額定功率
在正常工作中，一般由于能量損耗和機(jī)器性能等各方面的因素，我們選取液壓泵的能量轉(zhuǎn)換率為0.8，由此我們可以計(jì)算出電動(dòng)機(jī)的額定功率
由結(jié)果我們可以與資料進(jìn)行對(duì)比參照，由于我們只是計(jì)算出一個(gè)理論的電動(dòng)機(jī)功率，因此，我們需要選取的電動(dòng)機(jī)，其額定功率要略微高于理論值，所以選用Y225M—6型電動(dòng)機(jī)。
4.3選取液壓站元件
4.3.1確定控制元件
表4-1控制元件明細(xì)表
4.3.2明確油路連接
兩缸實(shí)際工作時(shí)，系統(tǒng)的實(shí)際流量和理論值之間還有誤差，因此我們需要重新進(jìn)行計(jì)算，讓液壓液體滿足實(shí)際工作時(shí)的需求。
表4-2兩缸實(shí)際工作情況
當(dāng)我們?nèi)r(shí)：
由計(jì)算結(jié)果我們可以看出，兩缸的油管尺寸不一致，因此我們需要選取根據(jù)不同的液壓缸來選取油管。
4.3.3選取油箱規(guī)格
我們通過計(jì)算計(jì)算可得：
因此查閱資料選定， 。
第五章 液壓系統(tǒng)性能校核
第五章 液壓站整體校核
5.1校核系統(tǒng)壓力值
液壓系統(tǒng)的壓力值要考慮到整體油路全部安裝完成后開始進(jìn)行測(cè)試，因此我們按照不同的工作進(jìn)程進(jìn)行壓力值得估算，我們首先計(jì)算油路過程中的壓力值測(cè)試，當(dāng)流量到達(dá)理論極限值時(shí)，油管能否承受相關(guān)的壓力。然后計(jì)算控制元件的壓力值在流量極限值時(shí)能否承受。最終測(cè)試液壓缸的壓力承受能力。
5.1.1夾緊缸工作過程校核
①當(dāng)機(jī)床處于快進(jìn)進(jìn)油時(shí)，我們可以計(jì)算得出總壓力損失為：
當(dāng)機(jī)床處于快進(jìn)回油時(shí)，我們可以計(jì)算得出總壓力損失為
②當(dāng)機(jī)床處于工進(jìn)進(jìn)油時(shí)，我們可以計(jì)算得出總壓力損失為：
當(dāng)機(jī)床處于工進(jìn)回油時(shí)，我們可以計(jì)算得出總壓力損失為：
③當(dāng)機(jī)床處于快退進(jìn)油時(shí)，我們可以計(jì)算得出總壓力損失為：
當(dāng)機(jī)床處于快退回油時(shí)，我們可以計(jì)算得出總壓力損失為：
5.1.2進(jìn)給缸工作過程校核
①當(dāng)機(jī)床處于快進(jìn)進(jìn)油時(shí)，我們可以計(jì)算得出總壓力損失為：
當(dāng)機(jī)床處于快進(jìn)回油時(shí)，我們可以計(jì)算得出總壓力損失為：
②當(dāng)機(jī)床處于工進(jìn)進(jìn)油時(shí)，我們可以計(jì)算得出總壓力損失為：
當(dāng)機(jī)床處于工進(jìn)回油時(shí)，我們可以計(jì)算得出總壓力損失為：
③當(dāng)機(jī)床處于快退進(jìn)油時(shí)，我們可以計(jì)算得出總壓力損失為
當(dāng)機(jī)床處于快退回油時(shí)，我們可以計(jì)算得出總壓力損失為：
5.2校核散熱系統(tǒng)
由于液壓站系統(tǒng)處于密封狀態(tài)，因此我們需要考慮到整體的散熱程度，會(huì)不會(huì)由于溫度太高引起液壓液體的蒸發(fā)，從而導(dǎo)致系統(tǒng)整體壓力不足。
通過計(jì)算結(jié)果我們可以看出，這個(gè)溫度并不會(huì)影響到實(shí)際工作，因此我們可以不采用散熱器。
參考文獻(xiàn)
第六章 總結(jié)
隨著國(guó)家經(jīng)濟(jì)不斷的發(fā)展，人們不斷追求生活質(zhì)量，要求機(jī)械越來越精密，而且我國(guó)屬于發(fā)展中國(guó)家，目前來說，重工業(yè)支持著我國(guó)經(jīng)濟(jì)的發(fā)展，而重工業(yè)的發(fā)展是以機(jī)械的發(fā)展為基礎(chǔ)的，而液壓傳動(dòng)自動(dòng)化是機(jī)械發(fā)展中尤為重要的一步。
鏜床液壓站的設(shè)計(jì)，在保證機(jī)械成功運(yùn)轉(zhuǎn)時(shí)，還需要注意機(jī)器的實(shí)用性能，機(jī)器要滿足性價(jià)比高，效率高，操作便利，維修便利和使用壽命長(zhǎng)等一些實(shí)際生產(chǎn)使用的原則。我們由題目確定的條件，通過計(jì)算選取合適的液壓元件和系統(tǒng)。首先對(duì)液壓原理圖進(jìn)行分析，得到完整的回路，選取合適的元件進(jìn)行組裝。本文完成了一下工作：
（1）機(jī)床工況分析及控制功能要求分析，在這個(gè)分析的結(jié)果下，完成了液壓系統(tǒng)的基本功能回路選擇和組合，并完成液壓系統(tǒng)原理圖；
（2）根根據(jù)原理圖進(jìn)行計(jì)算，判斷使用合理的元件；
（3）根據(jù)液壓系統(tǒng)已有各項(xiàng)指標(biāo)對(duì)液壓系統(tǒng)參數(shù)進(jìn)行計(jì)算校核，液壓系統(tǒng)滿足設(shè)計(jì)要求；
（4）液壓系統(tǒng)的裝配圖、零件圖繪制。
通過完成以上工作基本完成了液壓系統(tǒng)設(shè)計(jì)工作。
參 考 文 獻(xiàn)
[1] 王積偉，黃誼，章宏甲．液壓傳動(dòng) [M]．北京：機(jī)械工業(yè)出版社，2006．
[2] 張利平．液壓傳動(dòng)系統(tǒng)及設(shè)計(jì) [M]．北京：化學(xué)工業(yè)出版社，2005．
[3] 雷天覺，新編液壓工程手冊(cè) [M]．北京：北京理工大學(xué)出版社，1998．
[4] 路甬祥，液壓氣動(dòng)技術(shù)手冊(cè) [M]．北京：機(jī)械工業(yè)出版社，2002．
[5] 成大先，機(jī)械設(shè)計(jì)手冊(cè) [M]．北京：化學(xué)工業(yè)出版社，2002．
[6] 王春行，液壓控制系統(tǒng) [M]．北京：機(jī)械工業(yè)出版社，2002．
[7] 李狀云，液壓元件與系統(tǒng) [M]．北京：機(jī)械工業(yè)出版社，2002．
[8] 陳書杰.氣動(dòng)傳動(dòng)與控制，北京：冶金工業(yè)出版社，1991.
[9] 張利平，周蘭午，齊習(xí)娟，制造技術(shù)與機(jī)床[J], 2000(10):11-13.
[10] 盛小明, 165F曲軸箱組合鏜床液壓站設(shè)計(jì)[J],2003(1):177-178.
[11] 李長(zhǎng)志, WHC-160數(shù)控銑鏜床液壓系統(tǒng)故障分析兩例[J], 設(shè)備管理與維修, 2003(11):41-41.
[12] 王運(yùn)炎 朱莉主編《機(jī)械工程材料》機(jī)械工業(yè)出版社2008
[13] 左健民主編《液壓與氣壓傳動(dòng)》機(jī)械工業(yè)出版社2007
[14] 梁俊彥,李玉翔.機(jī)電一體化技術(shù)的發(fā)展及應(yīng)用[J].科技資訊,2007(9).
[15] 芮延年.機(jī)電一體化系統(tǒng)設(shè)計(jì)[M].北京機(jī)械工業(yè)出版社,2004.
[16] 章浩,張西良,周士沖.機(jī)電一體化技術(shù)的發(fā)展與應(yīng)用[J].農(nóng)機(jī)化研究,2006(7).
畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
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設(shè)計(jì)（論文）題目：
流水線專用鏜床液壓動(dòng)力系統(tǒng)設(shè)計(jì)--液壓站設(shè)計(jì)
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學(xué)生姓名： 學(xué) 號(hào)：
專 業(yè)：
所在學(xué)院：
指導(dǎo)教師：
職 稱：
20xx年 2月 27日
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1．本畢業(yè)設(shè)計(jì)（論文）課題應(yīng)達(dá)到的目的：
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本畢業(yè)設(shè)計(jì)課題的主要目的是培養(yǎng)學(xué)生綜合運(yùn)用所學(xué)的基礎(chǔ)理論、專業(yè)知識(shí)和專業(yè)基本技能分析和解決實(shí)際問題，訓(xùn)練初步工程設(shè)計(jì)的能力。根據(jù)機(jī)械設(shè)計(jì)、制造及其自動(dòng)化專業(yè)的特點(diǎn)，著重地培養(yǎng)以下幾方面能力：
1．調(diào)查研究、中外文獻(xiàn)檢索、閱讀與翻譯的能力；
2．綜合運(yùn)用基礎(chǔ)理論、專業(yè)理論和知識(shí)分析解決實(shí)際問題的能力；
3．查閱和使用專業(yè)設(shè)計(jì)手冊(cè)的能力；
4．設(shè)計(jì)、計(jì)算與繪圖的能力，包括使用計(jì)算機(jī)進(jìn)行繪圖的能力；
5．撰寫設(shè)計(jì)說明書（論文）的能力。
2．本畢業(yè)設(shè)計(jì)（論文）課題任務(wù)的內(nèi)容和要求（包括原始數(shù)據(jù)、技術(shù)要求、工作要求等）：
? 試設(shè)計(jì)用于流水線上箱體內(nèi)孔加工的專用鏜床的液壓動(dòng)力系統(tǒng)。鏜床采用液壓進(jìn)給系統(tǒng)自動(dòng)化加工。機(jī)床加工過程的工作循環(huán)為：工件安裝夾緊到位，刀頭快速接近工件，工進(jìn)速度鏜削內(nèi)孔，加工到位停止，刀頭快速退回。進(jìn)給刀頭及拖板最大行程500mm，最大加工進(jìn)給力12kN，最小進(jìn)給速度2 mm/s ，最大進(jìn)給速度不大于20 mm/s ，快進(jìn)速度60mm/s，快進(jìn)行程150 mm。要求保證加工質(zhì)量，自動(dòng)化，能效高，調(diào)速穩(wěn)定。
畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
3．對(duì)本畢業(yè)設(shè)計(jì)（論文）課題成果的要求〔包括圖表、實(shí)物等硬件要求〕：
1．畢業(yè)設(shè)計(jì)開題報(bào)告（文獻(xiàn)綜述2000字以上，列表附參考文獻(xiàn)16篇以上）；
2．畢業(yè)設(shè)計(jì)外文專業(yè)文獻(xiàn)閱讀及翻譯（原文和譯文，譯文3000漢字以上）；
3．論文大綱（撰寫論文章節(jié)目錄等）；
4．液壓系統(tǒng)原理圖；
5．液壓系統(tǒng)工況圖；
6．液壓系統(tǒng)液壓站總裝配圖；
7．部件裝配圖及零件圖；
8．設(shè)計(jì)計(jì)算說明書。
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4．主要參考文獻(xiàn)：
1．《液壓與氣壓傳動(dòng)》 姜繼海編 高等教育出版社 2009年5月 第二版
2.《液壓與氣壓傳動(dòng)》 左健民主編 機(jī)械工業(yè)出版社 2009年6月 第四版
3．《液壓傳動(dòng)設(shè)計(jì)指導(dǎo)書》 周誦明 編 華中理工大學(xué)出版社 1997年12月第一版
4. 《液壓與氣壓傳動(dòng)》 王積偉主編 機(jī)械工業(yè)出版社 2008年8月 第二版
5．《機(jī)械設(shè)計(jì)手冊(cè)》（下冊(cè)） 機(jī)械工業(yè)出版社 1974年1月 第一版
6．《新編液壓工程手冊(cè)》 雷天覺主編 北京理工大學(xué)出版社 1998年1月第一版
7．《動(dòng)力機(jī)械與液壓裝置》 朱學(xué)敏編 機(jī)械工業(yè)出版社 2004年4月第一版
畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
5．本畢業(yè)設(shè)計(jì)（論文）課題工作進(jìn)度計(jì)劃：
20xx.12.16-20xx.1.10 領(lǐng)任務(wù)書、開題
20xx.2.25-2.16.3.9 畢業(yè)實(shí)習(xí)調(diào)研，完成開題報(bào)告、中英文翻譯、論文大綱
20xx.3.19-20xx.4.25 提交論文草稿，4月中旬中期檢查
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Hydraulic system
Chapter 1 Introduction
Hydraulic Pump Station also known as the stations are independent h- ydraulic device.
It requested by the oil gradually. And controlling the hydraulic oil flow direction, pressure and flow rate, applied to the mainframe and hy- draulic devices separability of hydraulic machinery.
Users will be provided after the purchase hydraulic station and host of implementing agencies (motor oil or fuel tanks) connected with tubing, Hydraulic machinery can be realized from these movements and the work cycle.
Hydraulic pump station is installed, Manifold or valve combination, t- anks, a combination of electrical boxes.
Functional components :
Pump device -- is equipped with motors and pumps, hydraulic station is the source of power. to mechanical energy into hydraulic oil pressure can be.
Manifold -- from hydraulic valve body and channel assembled. Right direction for implementation of hydraulic oil, pressure and flow control.
Valve portfolio -- plate valve is installed in up board after board conn-
ects with the same functional IC.
Tank -- plate welding semi-closed containers, also loaded with oil filtering network, air filters, used oil, oil filters and cooling.
Electrical boxes -- at the two patterns. A set of external fuse terminal plate; distribution of a full range of electrical control.
Hydraulic Station principle : motor driven pump rotation, which pump oil absorption from the oil tank. to mechanical energy into hydraulic pressure to the station, hydraulic oil through Manifold (or valve combinations) realized the direction, pressure, After adjusting flow pipe and external to the cylinder hydraulic machinery or motor oil, so as to control the direction of the motive fluid transformation force the size and speed the pace of promoting the various acting hydraulic machinery.
1.1 A development course
China Hydraulic (including hydraulic, the same below), pneumatic and seals industrial development process can be broadly divided into three phases, namely : 20 early 1950s to the early 1960s, the initial stage; 60's and 70 for specialized production system ;80~90's growth stage for the rapid development stage. Which, hydraulic industry in the early 1950s from the machine tool industry production of fake Su-grinder, broaching machine, copying lathe, and other hydraulic drive started, Hydraulic Components from the plant hydraulic machine shop, self-occupied. After entering the 1960s, the application of hydraulic technology from the machine gradually extended to the agricultural machinery and mechanical engineering fields, attached to the original velocity of hydraulic shop some stand out as pieces of hydraulic professional production. To the late 1960s, early 1970s, with the development of mechanized production, especially in the second automobile factory in providing efficient, automated equipment, along with the Hydraulic Components manufacturing has experienced rapid development of the situation, a group of SMEs have become professional hydraulic parts factory. 1968 China's annual output of hydraulic components have nearly 200,000 in 1973, machine tools, agricultural machinery, mechanical engineering industries, the production of hydraulic parts factory has been the professional development of more than 100 and an annual output more than one million. an independent hydraulic manufacturing industry has begun to take shape. Then, hydraulic pieces of fake products from the Soviet Union for the introduction of the product development and technical design combining the products to the pressure, Hypertension, and the development of the electro-hydraulic servo valves and systems, hydraulic application areas further expanded. Aerodynamic than the start of the industrial hydraulic years later, in 1967 began to establish professional pneumatic components factory, Pneumatic Components only as commodity production and sales.Sealed with rubber and plastics, mechanical seals and sealing flexible graphite sealing industry, the early 1950s from the production ordinary O-rings.rubber and plastics extrusion, such as oil seal sealing and seal asbestos products start to the early 1960s, begun production of mechanical seals and flexible graphite sealing products. 1970s, the burning of the former Ministry, a Ministry, the Ministry of Agricultural Mechanization System, a group of professional production plants have been established, and the official establishment of industries to seal industrial development has laid the foundation for growth.
Since the 1980s, in the country's reform and opening up policy guidelines, with the development of the machinery industry, based mainframe pieces behind the conflicts have become increasingly prominent and attracted the attention of the relevant departments. To this end, the Ministry of the original one in 1982, formed the basis of common pieces of Industry, will be scattered in the original machine tools, agricultural machinery, mechanical engineering industries centralized hydraulic, pneumatic and seals specialized factories, placing them under common management infrastructure pieces Bureau, so that the industry in the planning, investment, technology and scientific research and development in areas such as infrastructure pieces Bureau of guidance and support. Since then entered a phase of rapid development, has introduced more than 60 items of advanced technology from abroad, including more than 40 items of hydraulic, pneumatic 7. After digestion and absorption and transformation, now have mass production, and industry-leading products. In recent years, the industry increased the technological transformation efforts, in 1991, Local enterprises and the self-financing total input of about 20 billion yuan, of which more than 1.6 billion yuan Hydraulic. Through technological transformation and technology research, and a number of major enterprises to further improve the level of technology, technique and equipment to be greatly improved. In order to form a higher starting point, specialization, and run production has laid a good foundation. In recent years, many countries in the development of common ownership guidelines, under different ownership SMEs rapid rise showing great vitality. With the further opening up, three-funded enterprises rapid development of industry standards for improving and expanding exports play an important role. Today, China has and the United States, Japan, Germany and other countries famous manufacturers joint ventures or wholly-owned by foreign manufacturers to establish a piston pump / motor, planetary reduction gears, steering gear, hydraulic control valve, hydraulic system, hydrostatic transmission, hydraulic Casting. pneumatic control valve, cylinder, gas processing triple pieces, mechanical seals, rubber and seal products more than 50 production enterprises, attracting foreign investment over 200 million U.S. dollars.
1.2 the current situation
1.21Basic Profiles
After 40 years of efforts, China hydraulic, pneumatic and sealing industry has formed a relatively complete categories. a certain level of technical capacity and the industrial system. According to the 1995 Third National Industrial Census statistics, hydraulic, Pneumatic seals and industrial 370,000 annual sales income of 100 million yuan in state-owned, village-run, private and cooperative enterprises, individual, "three capital" enterprises with a total of more than 1,300, of which about 700 hydraulic, Pneumatic seals and the approximately 300 thousand. By 1996 with the international trade statistics, the total output value of China's industry hydraulic 2.348 billion yuan, accounting for the world's 6; Pneumatic industry output 419 million yuan, accounting for world No. 10.
1.22the current supply and demand profiles
Through the introduction of technology, independent development and technological innovation, and high-pressure piston pump, gear pumps, vane pump, General Motors hydraulic valves, tanks, Non-lubricated aerodynamic pieces and various seals of the first large technology products has increased noticeably. stability of the mass production may, for various mainframe products provide a level of assurance. In addition, hydraulic and pneumatic components of the CAD system, pollution control, proportional servo technology has scored some achievements, and is already in production. Currently, hydraulic, pneumatic and seals products total about 3,000 species, more than 23,000 specifications. Among them, there are 1,200 hydraulic varieties, more than 10,000 specifications (including hydraulic products 60 varieties 500 specifications); Pneumatic are 1,350 varieties, more than 8,000 specifications; Rubber seal 350 species more than 5,000 specifications have been basically cater to the different types of mainframe products to the general needs, complete sets of equipment for major varieties of matching rate was over 60%, and started a small amount of exports.
1998 pieces of homemade hydraulic output 4.8 million.sales of about 28 billion (of which about 70% mechanical systems); aerodynamic pieces yield 3.6 million. sales of about 5.5 billion (of which about 60% of mechanical systems); Seals output of about 800 million. sales of about 10 billion (of which about 50% mechanical systems). According to the China Hydraulic Pneumatic Seals Industry Association 1998 annual report, hydraulic product sales rate of 97. 5% (101% for hydraulic), pneumatic 95.9%, 98.7% sealed. This fully reflects the basic marketing convergence.
My hydraulic, pneumatic and sealing industry has attained a great deal of progress, but with mainframe development needs, and the world's advanced level, there are still many gaps, mainly reflected in the product variety, performance and reliability, and so on. Hydraulic products as an example, products abroad only one-third, life for half abroad. In order to meet key mainframe, and mainframe imports of major technology and equipment needs, every year a large number of hydraulic, pneumatic and sealing products imports. According to customs statistics and the analysis of data, in 1998 hydraulic, pneumatic and seals in the import about 200 million U.S. dollars, Hydraulic which about 1.4 billion dollars, aerodynamic nearly 030 million U.S. dollars, sealed about 030 million U.S. dollars. compared with a slight decline in 1997. By sums, currently imported products on the domestic market share of about 30%. 1998 pieces of the domestic market demand for hydraulic total of about six million, the total sales of nearly 40 billion; aerodynamic pieces of the total demand of about 5 million, with sales more than 700 million yuan; Seals total demand of about 1.1 billion. total sales of about 1.3 billion.
1.3 the development trend of the future
1.31affect the development of the main factors
(1) product development ability, and the level of technological development and speed can not completely meet the advanced mainframe products, major equipment and technology imported equipment and maintenance support;
(2) the number of enterprises manufacturing technology, the level of equipment and management standards are comparatively backward, coupled with a strong sense of quality, resulting in low levels of product performance, quality, Reliability poor services in a timely manner, lack of user satisfaction and trust of the brand-name products;
(3) industry specialization of production low, scattered strength, low repeat serious, between regions and enterprises of convergence products, blindly compete with each other, driving down prices, the decline of enterprise returns, lack of funds, liquidity difficulties, product development and technological transformation is inadequate and seriously restricted the industry to improve the overall level of competition and the increase of strength;
(4) The internationalization of the domestic market and the increasing degree of foreign companies have entered the Chinese market and participate in competition with the domestic private and cooperative enterprises, individuals, foreign-funded enterprises, such as the rise of state-owned enterprises due to the growing impact.
1.32the development trend
As the socialist market economy continues to deepen, hydraulic, pneumatic and sealing products in the market supply and demand and there is a greater change, long ago to a "shortage" of the seller's market has basically become a "structural surplus" of the characteristics of the buyer's market place . Overall capacity, is already in oversupply situation, in particular the general low level of hydraulic, pneumatic and seals, the general oversupply; and the host of urgent high-tech high-parameter, high value-added high-end products, and they do not satisfy the market needs, only dependent on imports. China joins the WTO, its impact may be even greater. Therefore, the "15" during the growth of the output value of industry, must not depend on volume growth and the industry should address the structural problems of their own, increase the intensity of the adjustment of the industrial structure and product mix, is, we should rely on the improvement of quality, and promote technical upgrading of products to meet market demand and stimulating, seek greater development.
2 The application of hydraulic power sliding stage
2.1 Power sliding Taiwan introduced
This paper deals with the investigation for slide unit's impact and motion stabil?ity in modular machine tool fay means of the method of power bond graph and state space analysis. The dynamic mathematical model of self-adjusting back pressure speed control system used to drive slide unit is established. Main reasons and affect?ing factors for slide unit impact and motion unstability are analysed through compu?ter digital simulation, It is concluded from those that, if the structural dimensions of hydraulic cylinder and back pressure valve are designed rationally, the slide unit's dynamics will markedly be improved.
NOMENCLATURE
Sf flow source
Sei sliding friction force in slide unit
R equivalent viscous friction coefficient in slide unit
Ii mass of slide unit and cylinder
h mass of SABP valve spool
Ci,C2 hydraulic capacitances of rod chamber and non-rod chamber in cylinder re-
spec-tively
C3 spring compliance of SABP valve
R]rR2 hydraulic resistances of damping holes
R9 hydraulic resistance of orifice of SABP valve
Se2 presetting force of spring in SABP valve
I4J5 equivalent liquid inertia in pipe lines
C^Cg equivalent hydraulic capacitances in pipe lines
equivalent hydraulic resistances in pipe lines
V-j V^ oil-containing volumes in non-rod chamber and rod chamber respectively
P,r:, P-i oil pressures in non-rod chamber and rod chamber respectively
F load acted on slide unit
V slide unit velocity
* Department of Mechanical Engineering, Dalian Ur.iversity of Technology, Dalian. China.
2.2 Introduction
During operation of modular machine tool, the changes of slid unit's speed and load acted on it in both magnitude and direction will affect working performar.ee to a different extent Particularly the impact caused by sudden vanishing of load and the motion unstability due to periodical change of load in operation will affect the surface quality of the workpiece machined, and the tool would be broken off under serious conditions, By using the method of power bond graph and state space analy sis, the dynamic mathematical model of the system used to drive slide unit is estab lished, that is called as self-adjusting back pressure speed control system and abbre viated to SABP system. In order to improve slide unit's dynamics, it is necessary to find out the main reasons and affecting factors, that must be based on computer digital simulation and study on the results.
2.3Dynamic MathematicaModeld
The schematic diagram of SABP system is shown in Fig.l, the system is used to perform the cycle of feeding, stopping and returning. Four way control valve works in the right position during slide unit's feeding. The supply pressure of the pump is approximately constant under the action of pressure relief valve, the oil through the control valve and pressure compensated flow control valve enters the non-rod chamber to put slide unit forward. At the same time, the oil from the rod chamber is discharged through SABP valve and directional control valve to tank. In this process, the state of two check valves and pressure relief valve is not changed, To establish the mathematical model as reasonably and simply as possible, consid eration must be focused on main affecting factors for a complex non-linear system such as the SABP system. It is illustrated by theoretical analysis and test result ' , that the transient time of the system is much longer than that of the flow control valve, and the flowrate overshoot of the valve in transients affects very small to slide unit speed because of the ;large effective sectional area of non-rod chamber in cylinder. For investigating the system's dynamics widely and deeply, the initial mod eltn is further simplified in this paper, and so the study can be efficiently made with microcomputer. It is assumed that the flowrate through the flow control valve is
constant in the whole transient process, and is denoted to a flow source.Fig.2 shows the structure diagram of the dynamic model of the system, it is composed of cylin der, slide unit, SABP valve and pipe line; etc.
By using the method of power bond graph and state space analysis in this pap er, the dynamic mathematical model of the system is to be established- The power bond graph is a power flow diagram, which expresses abstractly the actions among sub-systems as three effects, i.e. resistance effect, capacitive effect and inertia effect, according to the way of energy transform, on the basis of practical structure and by means of method of lumped parameters. The model is characterized by a clear con ception in physics, and non-linear system can be accurately analysed in combination with method of state space analysis, thus it is a effective method used in the dyna mic investigation of complex non-linear system in the'timedomain.
From main performances of components in SAEP system, the power bond graph of the system has been formed by means of the rule of model establishing ' and is shown in Fig.3. Half arrow in each bond indicates a direction of power How, two variahles of power are effort variable and flow variable. O-junction illustrates algebraic summation of flow variables at common effort, i.e. parallel connection, 1-junction does algebraic summation of effort variables at common flow, i.e. series connection. The symbol TF represents power transformer between two types of energy, and transforming modulus between efforts or flows is noted below the sym bol TF. Short transverse bar across one end of each bond shows causality between two variables. A full arrow expresses a control action. Among three actions, there is an integration or differential form in capacitive effect and inertia effect between two variables. So state equation may be derived from Fig.3, there are nine state vari ables in this complex nonlinear equation. Studying on the slide unit's dynamics is started with impact and motion stability. The equation is simulated by using the method of 4th order Runge-Kutta integration procedure on IBM-PC computer. Fig.4 and Fig.5 illustrate the results respectively.
Slide unit's impact phenominon results from load's vanishing in the transients, ■for example, the situation of drilling through workpiece, Fig.4 expounds the varia tions of the load and speed of slide unit, the pressures of chambers in cylinder. When slide unit motions evenly under the action of load, the oil pressure in non-rod chamber is very high, and there is a lot of hydraulic energy accumulated in side. The pressure decreases at once with load's discharging rapidly. During the pro