液壓式組合建筑機(jī)械液壓部分設(shè)計(jì)【液壓式鋼筋彎曲切斷套絲多用機(jī)液壓系統(tǒng)設(shè)計(jì)】,液壓式鋼筋彎曲切斷套絲多用機(jī)液壓系統(tǒng)設(shè)計(jì),液壓式組合建筑機(jī)械液壓部分設(shè)計(jì)【液壓式鋼筋彎曲切斷套絲多用機(jī)液壓系統(tǒng)設(shè)計(jì)】,液壓式,組合,建筑機(jī)械,液壓,部分,部份,設(shè)計(jì),鋼筋,彎曲,曲折,切斷,割斷,多用 說明書 第 II 頁 多用途建筑機(jī)械液壓部分設(shè)計(jì) 摘 要 多用途建筑機(jī)械具有節(jié)約能源，加工效率高，重量小等特點(diǎn)。本文較為詳細(xì)的介紹了多用機(jī)液壓部分的設(shè)計(jì)過程和產(chǎn)品使用說明。 全文包括液壓系統(tǒng)切斷、彎曲和套絲三個(gè)支路的工作原理，切斷支路通過液動(dòng)換向閥隨著壓力升高的換向，啟用增壓缸工作為切斷缸增壓的原理。通過對(duì)鋼筋切斷力、彎曲和套絲扭矩的計(jì)算以及系統(tǒng)工況的分析，計(jì)算確定了液壓系統(tǒng)的各主要參數(shù)，獨(dú)立設(shè)計(jì)了切斷缸和增壓缸，選擇了液壓系統(tǒng)各執(zhí)行和控制元件。設(shè)計(jì)集中布置液壓裝置，即將系統(tǒng)的執(zhí)行元件安放在主機(jī)上，將液壓泵及驅(qū)動(dòng)電機(jī)、控制元件、輔助元件等獨(dú)立裝在主機(jī)之外集中設(shè)置。將液壓控制元件均勻水平的布置在油箱的頂蓋上，液壓動(dòng)力源裝置采用臥式液壓動(dòng)力源，即將電機(jī)臥式安裝，液壓泵置于油箱之上。 液壓系統(tǒng)工作性能的保持，應(yīng)該正確的使用與及時(shí)維護(hù)，操作者應(yīng)熟悉系統(tǒng)的工作原理和操作要點(diǎn)。液壓工作站應(yīng)定期維護(hù)檢查。 關(guān)鍵詞：切斷,彎曲,套絲,液壓工作站 The Liquid Pressure Design of Multi-purpose Architecture Machine Author : Cheng kunpeng Tutor : Zou Jingchao Abstract The multi-purpose architecture machine has the economy energy with the machine tool much, processing the efficiency higher , the weight small etc. characteristics. This text compares to introduced to use the procedure of design and the instruction of product of the machine hydraulic pressure fraction more detailedly. The full text includes the hydraulic pressure system cutting, flexure and three operate principles of derived circuit of silk of set, cutting off the derived circuit to moves the reversing valve through a liquid to go up along with the press of change to, the invocation super' presses an urn of operate into the principle that cut off an urn of super 's press, pass each main parameter of system to really settle, select each execution of system of hydraulic pressure and control elements, independently designed the cutting the urn and super 's press the urn. The design concentrates to arrange the hydraulic pressure device, will soon the execution component dress of the system is on the host, packing hydraulic pump and drive the dynamo, control element and lend support to the component, etc. independently in the host outside concentrated setups. Cover the vertex that the even horizontal of the hydraulic pressure control element arrange in the oil reservoir, the hydraulic pressure power source device adoption sign type hydraulic pressure power source, will soon the dynamo sign type setup, the hydraulic pump is place on oil reservoir . The one who press the hold of the system operate performance, should accurate usage with support in time, operate should acquaint with the operate principle and the operation mains of the system. Workstation of hydraulic pressure should the schedule maintenance inspection. Key words: Cutting ，F(xiàn)lexure，Silk of set，Workstation of hydraulic pressure 文獻(xiàn)綜述） 第 8 頁 液壓技術(shù)在建筑機(jī)械中的應(yīng)用及發(fā)展情況 1 選題背景 在鋼筋混凝土結(jié)構(gòu)工程中由于鋼筋加工生產(chǎn)落后于商品混凝土和建筑模板，現(xiàn)已成為制約施工機(jī)械化程度提高的瓶頸。在建筑工程中,鋼筋的彎曲、切斷作業(yè)量是非常巨大的,但目前,除鋼筋的切斷多為機(jī)械作業(yè)外,彎曲作業(yè)仍以人工作業(yè)為主,致使所加工出的鋼筋在同一規(guī)格中尺寸大小不一,質(zhì)量不好,且工人勞動(dòng)強(qiáng)度大,效率低。造成這種現(xiàn)象的原因主要是國內(nèi)鋼筋加工設(shè)備的型式及規(guī)格不全。目前,我國鋼筋加工設(shè)備主要有兩種形式,一是手動(dòng)操縱設(shè)備,如鋼筋切斷機(jī)、鋼筋彎曲機(jī)等。該類設(shè)備的主要缺點(diǎn)是功能單一,基本參數(shù)需人為控制(如彎曲角度需人眼確定) ,效率低、操作也不方便,所以該類設(shè)備只適用于人力不可及的粗鋼筋加工,對(duì)于成批大量的細(xì)鋼筋加工仍以人工手工作業(yè)為主; 二是自動(dòng)化程度高的鋼筋加工設(shè)備,雖然該類設(shè)備效率很高、質(zhì)量也很好,但價(jià)格昂貴,在目前國內(nèi)經(jīng)濟(jì)條件下,大多數(shù)施工單位不愿購置。如果將鋼筋的彎曲、切斷、套絲三種作業(yè)設(shè)備合三為一,既減少了鋼筋加工的設(shè)備數(shù)量,又節(jié)約了能源。鑒于以上的情況，有必要設(shè)計(jì)一種由液壓系統(tǒng)統(tǒng)一提供動(dòng)力的多用途鋼筋鋼管加工機(jī)械，可以適用于中小型建筑隊(duì)，該加工機(jī)動(dòng)作方便靈活，便于掌握，移動(dòng)，安裝簡便可靠。 2 資料綜述 液壓與氣壓傳動(dòng)是研究以有壓流體（壓力油或壓縮空氣）為能源介質(zhì)，來實(shí)現(xiàn)各種機(jī)械的傳動(dòng)和自動(dòng)控制的學(xué)科。液壓傳動(dòng)與氣壓傳動(dòng)實(shí)現(xiàn)傳動(dòng)和控制的方法是基本相同的，它們都是利用各種控制元件組成所需要的各種控制回路，再由若干回路有機(jī)組合成能完成一定控制功能的傳動(dòng)系統(tǒng)來進(jìn)行能量的傳遞、轉(zhuǎn)換與控制。因此，要研究液壓與氣壓傳動(dòng)及其控制技術(shù)，就首先要了解傳動(dòng)介質(zhì)的基本物理特性及其靜力學(xué)、運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)特性；要了解組成系統(tǒng)的各類液壓與氣動(dòng)元件的結(jié)構(gòu)、工作原理、工作性能以及由這些元件所組成的各種控制回路的性能和特點(diǎn)，并在此基礎(chǔ)上進(jìn)行液壓與氣壓傳動(dòng)控制系統(tǒng)的設(shè)計(jì)[1]。 2.1液壓傳動(dòng) 2.1.1 液壓傳動(dòng)的應(yīng)用范圍的基本原理 液壓傳動(dòng)有許多突出的優(yōu)點(diǎn)，因此它的應(yīng)用非常廣泛，如一般工業(yè)用的塑料加工機(jī)械、壓力機(jī)械、機(jī)床等；行走機(jī)械中的工程機(jī)械、建筑機(jī)械、農(nóng)業(yè)機(jī)械、汽車等；鋼鐵工業(yè)用的冶金機(jī)械、提升裝置、軋輥調(diào)整裝置等；土木水利工程用的防洪閘門及堤壩裝置、河床升降裝置、橋梁操縱機(jī)構(gòu)等；發(fā)電廠渦輪機(jī)調(diào)速裝置、核發(fā)電廠等等；船舶用的甲板起重機(jī)械（絞車）、船頭門、艙壁閥、船尾推進(jìn)器等；特殊技術(shù)用的巨型天線控制裝置、測量浮標(biāo)、升降旋轉(zhuǎn)舞臺(tái)等；軍事工業(yè)用的火炮操縱裝置、船舶減搖裝置、飛行器仿真、飛機(jī)起落架的收放裝置和方向舵控制裝置等。 液壓傳動(dòng)的基本原理是在密閉的容器內(nèi)，利用有壓力的油液作為工作介質(zhì)來實(shí)現(xiàn)能量轉(zhuǎn)換和傳遞動(dòng)力的。其中的液體稱為工作介質(zhì)，一般為礦物油，它的作用和機(jī)械傳動(dòng)中的皮帶、鏈條和齒輪等傳動(dòng)元件相類似。 液壓傳動(dòng)所用的工作介質(zhì)為液壓油或其他合成液體，氣壓傳動(dòng)所用的工作介質(zhì)為空氣。由于這兩種流體的性質(zhì)不同，所以液壓傳動(dòng)和氣壓傳動(dòng)又各有其特點(diǎn) [2]。 2.1.2、液壓傳動(dòng)的優(yōu)點(diǎn) (1) 液壓傳動(dòng)可以輸出大的推力或大轉(zhuǎn)矩，可實(shí)現(xiàn)低速大噸位運(yùn)動(dòng)，這是其它傳動(dòng)方式所不能比的突出優(yōu)點(diǎn)。 (2) 液壓傳動(dòng)能很方便地實(shí)現(xiàn)無級(jí)調(diào)速，調(diào)速范圍大，且可在系統(tǒng)運(yùn)行過程中調(diào)速。 (3) 在相同功率條件下，液壓傳動(dòng)裝置體積小、重量輕、結(jié)構(gòu)緊湊。液壓元件之間可采用管道連接、或采用集成式連接，其布局、安裝有很大的靈活性，可以構(gòu)成用其它傳動(dòng)方式難以組成的復(fù)雜系統(tǒng)。 (4) 液壓傳動(dòng)能使執(zhí)行元件的運(yùn)動(dòng)十分均勻穩(wěn)定，可使運(yùn)動(dòng)部件換向時(shí)無換向沖擊。而且由于其反應(yīng)速度快，故可實(shí)現(xiàn)頻繁換向。 (5) 操作簡單，調(diào)整控制方便，易于實(shí)現(xiàn)自動(dòng)化。特別是和機(jī)、電聯(lián)合使用時(shí)，能方便地實(shí)現(xiàn)復(fù)雜的自動(dòng)工作循環(huán)。 (6) 液壓系統(tǒng)便于實(shí)現(xiàn)過載保護(hù)，使用安全、可靠。由于各液壓元件中的運(yùn)動(dòng)件均在油液中工作，能自行潤滑，故元件的使用壽命長。 (7) 液壓元件易于實(shí)現(xiàn)系列化、標(biāo)準(zhǔn)化和通用化，便于設(shè)計(jì)、制造、維修和推廣使用。 2.1.3液壓傳動(dòng)的缺點(diǎn) (1) 液壓傳動(dòng)以液體作為工作介質(zhì)，在液壓元件中相對(duì)運(yùn)動(dòng)的摩擦副間無法避免泄漏，再加上液體壓縮性及管路彈性變形等原因，難以實(shí)現(xiàn)嚴(yán)格的傳動(dòng)比。 ????(2)．液體粘度和溫度有密切關(guān)系，當(dāng)粘度隨溫度變化時(shí)，將直接影響泄漏、壓力損失及通過節(jié)流元件的流量等，從而引起執(zhí)行元件運(yùn)動(dòng)特性的變化。 ????(3)．傳動(dòng)效率較低。液壓系統(tǒng)中能量要經(jīng)過兩次轉(zhuǎn)換，在能量轉(zhuǎn)換及傳遞過程中存在機(jī)械摩擦損失、壓力損失及泄漏損失。 ????(4)．液壓元件的制造精度要求高，造價(jià)較貴。使用、維護(hù)要求有一定的專業(yè)知識(shí)和較高的技術(shù)水平。 ?? ?(5)．液壓能的獲得與傳遞不如電能方便。 （6）．液壓系統(tǒng)中各種元件、輔件及工作介質(zhì)均在封閉的系統(tǒng)內(nèi)工作，故障征兆難以及時(shí)發(fā)現(xiàn)，故障原因較難確定。 2.2 氣壓傳動(dòng) 1、氣壓傳動(dòng)的優(yōu)點(diǎn) （1）空氣可以從大氣中取之不竭，無介質(zhì)費(fèi)用和供應(yīng)上的困難，將過的氣體排入大氣，處理方便。泄漏不會(huì)影響工作，不會(huì)污染環(huán)境。 （2）空氣的粘性很小，在管路中阻力損失遠(yuǎn)遠(yuǎn)小于液壓傳動(dòng)系統(tǒng)，宜于遠(yuǎn)程傳輸及控制。 （3）工作壓力低，元件的材料和制造精度低。 （4）維護(hù)簡單，使用安全，無油的氣動(dòng)控制系統(tǒng)特別適用于無線電元器件的生產(chǎn)過程，也適用于食品及醫(yī)藥的生產(chǎn)過程。 （5）氣動(dòng)元件可以根據(jù)不同場合，采用相應(yīng)材料，使元件能夠在惡劣的環(huán)境（強(qiáng)振動(dòng)、強(qiáng)沖擊、強(qiáng)腐蝕和強(qiáng)輻射等）下進(jìn)行正常工作。 2、氣壓傳動(dòng)缺點(diǎn) （1）氣壓傳動(dòng)裝置的信號(hào)傳遞速度限制在聲速（約340m/s）范圍內(nèi)，所以它的工作效率和響應(yīng)速度不如電子裝置，并且信號(hào)要產(chǎn)生較大的失真和延滯，也不便于構(gòu)成較復(fù)雜的控制系統(tǒng)，但這個(gè)缺點(diǎn)對(duì)工業(yè)生產(chǎn)過程不會(huì)造成困難。 （2）空氣的壓縮性遠(yuǎn)大于液壓油的壓縮性，因此在動(dòng)作的響應(yīng)能力、工作速度的平穩(wěn)性不如液壓傳動(dòng)。 （3）氣壓傳動(dòng)系統(tǒng)出力較小，且傳動(dòng)效率低[3]。 2.3液壓與氣壓傳動(dòng)的發(fā)展 液壓與氣壓傳動(dòng)發(fā)展到目前的水平主要是由于液壓與氣壓傳動(dòng)本身的特點(diǎn)所致，隨著工業(yè)的發(fā)展，液壓與氣壓傳動(dòng)技術(shù)必將更加廣泛地應(yīng)用于各個(gè)工業(yè)領(lǐng)域。 液壓技術(shù)自18世紀(jì)末英國制成世界上第一臺(tái)水壓機(jī)算起，已有300多年的歷史了，但其真正的發(fā)展只是在第二次世界大戰(zhàn)后近60年的時(shí)間內(nèi)，戰(zhàn)后液壓技術(shù)迅速轉(zhuǎn)向民用工業(yè)，在機(jī)床、工程機(jī)械、農(nóng)業(yè)機(jī)械、汽車等行業(yè)中逐步推廣。20世紀(jì)60年代以來，隨著原子能技術(shù)、空間技術(shù)、計(jì)算機(jī)技術(shù)的發(fā)展，液壓技術(shù)得到了很大的發(fā)展，并滲透到各個(gè)工業(yè)領(lǐng)域中去。當(dāng)前液壓技術(shù)正向高壓、高速、大功率、高效、低噪聲、經(jīng)久耐用、高度集成化的方向發(fā)展。同時(shí)，新型液壓元件和液壓系統(tǒng)的計(jì)算機(jī)輔助設(shè)計(jì)（CAD）、計(jì)算機(jī)輔助測試(CAT)、計(jì)算機(jī)直接(CDC)、計(jì)算機(jī)實(shí)時(shí)控制技術(shù)、機(jī)電一體化技術(shù)、計(jì)算機(jī)仿真和優(yōu)化設(shè)計(jì)技術(shù)、可靠性技術(shù)，以及污染控制技術(shù)等方面也是當(dāng)前液壓傳動(dòng)及控制技術(shù)發(fā)展和研究的方向。 氣壓傳動(dòng)技術(shù)在科技飛速發(fā)展的當(dāng)今世界發(fā)展將更加迅速。隨著工業(yè)的發(fā)展，氣壓技術(shù)的應(yīng)用領(lǐng)域已從汽車、采礦、鋼鐵、機(jī)械工業(yè)等行業(yè)擴(kuò)展到化工、輕工、食品、軍事工業(yè)等各行各業(yè)。氣動(dòng)技術(shù)已發(fā)展成包含傳動(dòng)、控制與檢測在內(nèi)的自動(dòng)化技術(shù)。由于工業(yè)自動(dòng)化技術(shù)的發(fā)展。氣動(dòng)控制技術(shù)以提高系統(tǒng)可靠性，降低總成本為目標(biāo)。研究和開發(fā)系統(tǒng)控制技術(shù)和機(jī)、電、液、氣綜合技術(shù)。顯然，氣動(dòng)元件當(dāng)前發(fā)展的特點(diǎn)和研究方向主要是節(jié)能化、小型化、輕量化、位置控制的高精度化，以及與電子學(xué)相結(jié)合的綜合控制技術(shù)。 液壓系統(tǒng)主要由：動(dòng)力元件（油泵）、執(zhí)行元件（油缸或液壓馬達(dá)）、控制元件（各種閥）、輔助元件和工作介質(zhì)等五部分組成。 (1) 動(dòng)力元件（油泵） 動(dòng)力元件起著向系統(tǒng)提供動(dòng)力源的作用，是系統(tǒng)不可缺少的核心元件。液壓系統(tǒng)是以液壓泵為系統(tǒng)提供一定的流量和壓力的動(dòng)力元件， 它的作用是把液體利用原動(dòng)機(jī)的機(jī)械能轉(zhuǎn)換成液壓力能，是一種能量轉(zhuǎn)換裝置，是液壓傳動(dòng)中的動(dòng)力部分。 選擇液壓泵的原則是：根據(jù)主機(jī)工況、功率大小和系統(tǒng)對(duì)工作性能的要求，首先確定液壓泵的類型，然后按系統(tǒng)所要求的壓力、流量大小確定其規(guī)格型號(hào)。 (2) 執(zhí)行元件（油缸、液壓馬達(dá)） 它是將液體的液壓能轉(zhuǎn)換成機(jī)械能。其中，油缸做直線運(yùn)動(dòng)，馬達(dá)做旋轉(zhuǎn)運(yùn)動(dòng)。液壓馬達(dá)按其結(jié)構(gòu)類型來分可以為齒輪式、葉片式、柱塞式和其它型式。按液壓馬達(dá)的額定轉(zhuǎn)速分為高速和低速兩大類。額定轉(zhuǎn)速高于500r/min的屬于高速液壓馬達(dá)，額定轉(zhuǎn)速低于500r/min的屬于低速液壓馬達(dá)。高速液壓馬達(dá)的基本形式有齒輪式、螺桿式、葉片式和軸向柱塞式等。它們的主要特點(diǎn)是轉(zhuǎn)速較高、轉(zhuǎn)動(dòng)慣量小，便于起動(dòng)和制動(dòng)，調(diào)節(jié)（調(diào)速及換向）靈敏度高。通常高速液壓馬達(dá)輸出轉(zhuǎn)矩不大（僅幾十牛.米到幾百牛.米）所以又稱為高速小轉(zhuǎn)矩液壓馬達(dá)。低速液壓馬達(dá)的基本形式是徑向柱塞式，此外在徑向柱塞式、葉片式和齒輪式中也有低速的結(jié)構(gòu)形式。低速液壓馬達(dá)的主要特點(diǎn)是排量大、體積大、轉(zhuǎn)速低（有時(shí)可達(dá)每分鐘幾轉(zhuǎn)或零點(diǎn)幾轉(zhuǎn)），因此可直接與工作機(jī)構(gòu)連接，不需要減速裝置，使轉(zhuǎn)動(dòng)機(jī)構(gòu)大為簡化。通常低速液壓馬達(dá)輸出轉(zhuǎn)矩較大（可達(dá)幾千牛.米到幾萬牛.米），所以又稱為低速達(dá)轉(zhuǎn)矩液壓馬達(dá)。 (3) 控制元件 包括壓力閥、流量閥和方向閥等。它們的作用是根據(jù)需要無級(jí)調(diào)節(jié)液動(dòng)機(jī)的速度，并對(duì)液壓系統(tǒng)中工作液體的壓力、流量和流向進(jìn)行調(diào)節(jié)控制。 液壓傳動(dòng)系統(tǒng)對(duì)液壓控制閥的基本要求是：動(dòng)作靈敏、使用可靠，工作是沖擊和振動(dòng)要小，使用壽命長。油液通過液壓閥壓力損失要小，密封性能好，內(nèi)泄漏要小，無外泄漏。結(jié)構(gòu)簡單緊湊，安裝、維護(hù)、調(diào)整方便，通用性好[4]。通常對(duì)于液壓閥所應(yīng)用的各種滑閥、錐閥、節(jié)流孔口等均可按紊流流量方程對(duì)閥口的流量進(jìn)行計(jì)算[5]。 (4) 輔助元件 除上述三部分以外的其它元件，包括壓力表、濾油器、蓄能裝置、冷卻器、管件及油箱等，它們同樣十分重要。 (5) 工作介質(zhì) 工作介質(zhì)是指各類液壓傳動(dòng)中的液壓油或乳化液，它經(jīng)過油泵和電動(dòng)機(jī)實(shí)現(xiàn)能量轉(zhuǎn)換。 2.4剪切裝置 高質(zhì)量的下料對(duì)高質(zhì)量的產(chǎn)品和企業(yè)經(jīng)濟(jì)效益都具有重要的意義．傳統(tǒng)的下料方法大多采用帶鋸、車削和普通的剪切方法[6]。沖壓是使用模具分離材料的一種基本工具，它可以直接制成零件或?yàn)槠渌麤_擊工序，如彎曲，拉伸，成型等準(zhǔn)備毛坯，也可以在已經(jīng)成型的沖壓件上進(jìn)行切口修邊等。沖壓設(shè)備選用機(jī)械壓力機(jī)，中小型沖壓件選用開式曲柄壓力機(jī)，大中型沖壓件選用閉式曲柄壓力機(jī)。進(jìn)行大批量生產(chǎn)一般采用高速自動(dòng)壓力機(jī)。沖壓質(zhì)量與凸凹模的相對(duì)間隙有關(guān)。間隙越大，沖材質(zhì)量越低。 沖壓加工管材具有生產(chǎn)效率高，質(zhì)量好等優(yōu)點(diǎn)，其缺點(diǎn)是切斷時(shí)易被壓扁。為了減少管材被壓扁的程度，通常將凹模做成少許的桃型。在沖壓前，使管材在右半凹模的強(qiáng)力夾持下產(chǎn)生一定的反變形，然后再由沖刀沖切，從而減小管件被切刀壓扁的程度[7] 2.5套絲裝置 套絲是利用板牙在工件外表面上加工出外螺紋的方法。板牙是加工外螺紋的刀具，形似螺母，其上有數(shù)個(gè)排屑孔，并靠它構(gòu)成切削刃，板牙的兩面都有成錐形的切削部分，可任選一面套絲，中間是校準(zhǔn)部分，也是套口的導(dǎo)向部分，其修正和導(dǎo)向作用[8][9]。 2.6液壓CAD技術(shù) CAD技術(shù)使人工設(shè)計(jì)方式變?yōu)樽詣?dòng)化和半自動(dòng)化的方式，尤其是CAD／CAPP／CAM的推廣和應(yīng)用使液壓技術(shù)得到迅速發(fā)展。在液壓CAD的開發(fā)和研究方面應(yīng)注意以下幾點(diǎn)：①充實(shí)現(xiàn)有的液壓CAD設(shè)計(jì)軟件，進(jìn)行二次開發(fā)，建立知識(shí)庫信息系統(tǒng)，它將構(gòu)成設(shè)計(jì)—制造—銷售—使用—設(shè)計(jì)的閉式循環(huán)系統(tǒng)。②將計(jì)算機(jī)的仿真及適時(shí)控制結(jié)合起來，將模型放入“硬”件和系統(tǒng)中，借此在建造實(shí)際樣機(jī)之前，便可在軟件里修改其特性參數(shù)，以達(dá)到最佳設(shè)計(jì)結(jié)果[10] 2.7新材料、新工藝的應(yīng)用 　 新型材料的使用，如陶瓷、砌塊、聚合物或涂敷料，可使液壓的發(fā)展引起新的飛躍。為了保護(hù)環(huán)境，減少漏油對(duì)環(huán)境危害，可采用生物降解迅速的壓力流體，如菜油基和合成脂基的傳動(dòng)用介質(zhì)將得到廣泛應(yīng)用[11]。據(jù)專家預(yù)測，今后十年大部分行走機(jī)械中使用的液壓油（礦物油）將會(huì)為生物降解迅速的流體所替代。鑄造工藝的發(fā)展，將促進(jìn)液壓元件性能的提高，如鑄造流道在閥體和集成塊中的廣泛使用，可優(yōu)化元件內(nèi)部流動(dòng)，可減少壓力損失和降低噪聲，實(shí)現(xiàn)元件小型化。 如果上述提高液壓技術(shù)的方向得到充分實(shí)現(xiàn)[12]。 3 小結(jié) 本設(shè)計(jì)中彎曲和套絲裝置若采用傳統(tǒng)的減速方式，必然導(dǎo)致減速機(jī)構(gòu)相當(dāng)?shù)凝嫶螅昧艘簤杭夹g(shù)，用液壓元件來控制執(zhí)行元件，可以實(shí)現(xiàn)無級(jí)調(diào)速，使機(jī)構(gòu)大為簡化，而且利用液壓傳動(dòng)易于實(shí)現(xiàn)自動(dòng)化控制。本設(shè)計(jì)中的切斷可以由液壓缸帶動(dòng)刀具運(yùn)動(dòng)實(shí)現(xiàn)，套絲和彎曲可以由回轉(zhuǎn)液壓缸或馬達(dá)帶動(dòng)工作盤旋轉(zhuǎn)實(shí)現(xiàn)對(duì)工件的彎曲和套絲?？梢钥隙?，液壓技術(shù)和其他傳動(dòng)方式相比將繼續(xù)保持其有力的競爭。 在設(shè)計(jì)中還要注意液壓回路的選擇，達(dá)到所需要的設(shè)計(jì)要求。還考慮成本，盡量做到最好性價(jià)比，使設(shè)備發(fā)揮最好性能。  參考文獻(xiàn) [1] 左健民.液壓與氣壓傳動(dòng)[M]. 機(jī)械工業(yè)出版社,2006:5-11. [2] 賀利樂 .建筑機(jī)械液壓與液力傳動(dòng). 北京：機(jī)械工業(yè)出版社2004.2. [3] 張利平.液壓與氣壓技術(shù)手冊[M].北京：化學(xué)工業(yè)出版社,2007:20-25. [4] 王煥菊.液壓與氣壓傳動(dòng)[M] .北京：機(jī)械工業(yè)出版社,2007:78-80. [5] 馬長林，高欽和，李鋒.液壓系統(tǒng)仿真中幾種閥口流量模型的解算分析[J] .維普資訊，2007（11）：02. [6] 張平.液氣式高速棒料剪切機(jī)的原理及動(dòng)態(tài)分析[J] .蘭州理工大學(xué)學(xué)報(bào)，2006（06）06：03-04. [7] 張利平.液壓站設(shè)計(jì)與使用[M].北京:海洋出版社,2004.2： [8] 王文光.高速攻絲技術(shù)的研究狀態(tài)工具展望[J] .2002:3-4. [9] 楊文淵.簡明工程機(jī)械施工手冊[M] .華南理工大學(xué)出版社,2001:100-120. [10] Backe, W. Hydraulic drives with high efficiency. In Fluid power Systems and Technology, 1995, FPST-Vol.2, pp.45-73. [11] Zdeblick Abitbol JJ, Kunz DN McCabe RP.Garfin S (1993) Cervical stability after sequential capsule resction.Spine 14:2005-2008. [12] 邵承林，崔崇鋼，顧守泉.建筑機(jī)械[J] .2001（03）：6-8. [13] 路甬祥.液壓起動(dòng)技術(shù)手冊[M]北京：機(jī)械工業(yè)出版社，2003.6 設(shè)計(jì) 文獻(xiàn)綜述 院（系）名稱 專業(yè)名稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 學(xué)生姓名 指導(dǎo)教師 2012年 3 月 5 日 設(shè)計(jì) 文獻(xiàn)翻譯 院（系）名稱 專業(yè)名稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 學(xué)生姓名 指導(dǎo)教師 2012年 3 月 5 日 Nonlinear Dyn (2007) 47:219233 DOI 10.1007/s11071-006-9069-1 ORIGINAL ARTICLE Deregularization of a smooth system example hydraulics Friedrich Pfeiffer Received: 29 August 2005 / Accepted: 28 October 2005 / Published online: 1 November 2006 C Springer Science + Business Media B.V. 2006 Abstract Many technical systems include steep char- acteristics for force laws, which as a rule lead to stiff differential equations and large computing times. For the dynamical performance such steep characteristics are very near to laws with set-valued properties and might therefore be replaced by set-valued force laws. This is true for multibody dynamics including unilat- eral contacts, and it is in an approximate way true for fluid mechanical systems like hydraulics. In the follow- ing we present a new modeling scheme for hydraulic systems, which establishes the hydraulic equations of motion in the form of multibody system eqations with bilateral and unilateral constraints, and which is able to reduce computing times by three to four order of magnitudes. A large industrial example illustrates the excellent performance of the new theory. Keywords Deregularization of smooth systems Complementarities System models Hydraulics 1. Introduction Models approximate the physical or technical reality. They are more or less detailed, but all models include F. Pfeiffer Institute of Applied Mechanics, Technical University Munich, Boltzmannstrasse 15, D-85748 Garching, Germany e-mail: pfeifferamm.mw.tum.de some degree od approximation. The real world can- not be modeled in a perfect way. Therefore, in estab- lishing models we should keep in mind, that technical systems and especially technical mechanics are not de- ductive systems. This is true for classical analytical mechanics, which applies only partly to problems of some realistic significance. A further aspect concerns the goals connected with models. Do we want to map reality as perfect as possible, or do we want to consider certain parameter influences? Both objectives include difficult problems, because a model is by itself dumb. We have to make a model intelligent by introducing into it our knowledge of the problem under consider- ation, the physical and technical properties as good as we understand them, the parameter influences as good as we might expect them, the neglections as good as we can estimate them. This all is more an art than a science, but it is so essential, that no good model can be established without a preliminary phase of physical, of mechanical argueing leading to a sound imagination and a sound picture of the real world problem to be modeled. Simple models for the evaluation of tendencies with respect to the performance of a system include some re- ally difficult problems, because such simple models not only afford a perfect view of the overall system but also a perfect idea of what is important and of what is not important. In addition simple system modeling might be faulty, because the interference of many degrees of freedom might result in a completely different dynam- ical behavior as compared with simple considerations. Springer 220 Nonlinear Dyn (2007) 47:219233 A recently published finding with respect to the well known friction problem of self-excited oscillations con- nected with falling characteristics illustrates especially this danger of coming out with incorrect results. Includ- ing more than one degree of freedom it can be shown, that self-excited oscillations may happen also for an increasing and not for a falling characteristic 2. After having dealt with this model finding phase, which by the way is usually very much underestimated, we must find a decision on the mathematical and es- pecially on the numerical tools we want to apply. For one and the same problem we have a variety of possi- ble mathematical descriptions with again a certain va- riety of numerical algorithms. Some usual criteria for this choice are physical-mathematical correspondence, structural features of the resulting equations, transfor- mation capabilities with the goal of analytical or partly analytical solutions, convergence of the solutions, sta- bility of the numerical algorithms and finally the repre- sentation of the results allowing clear interpretations. Coming back to our problem of descibing systems with force laws including very steep characteristics we may apply two approaches, a smooth and a non- smooth one. In practical engineering characteristics with steep features occur in connection with contact problems, with fluidmechanical problems of hydraulic equipment, with cavitation or with electronic switch- ing problems, to name only a few examples. From the mathematical and from the resulting numerical stand- point of view such characteristics produce either stiff differential equations or they require a complementar- ity formulation. The decision which way to go depends mainly on the computation time. Considering contacts and related problems we might discretize a contact by evaluating the local stiffness properties of the contact, which allows the derivation of a force law. As contact stiffnesses are usually very large, we come out with stiff differential equations. The second way consists in assuming the local contact area as rigid, which does not imply that the whole body must be assumed rigid, and to formulate the contact proper- ties by complementarities 7, 8. In hydraulic networks we find such a complementarity behavior in connection with check valves, with servo valves and with cavitation in fluid-air-mixtures. For example a check valve might be open, then we have approximately no pressure drop, but a certain amount of the flow rate. Or a check valve might be closed, then we have a pressure drop, but no flow rate. A small amount of air in the fluid will be compressed by a large pressure to a neglectable small air volume, but for a very small pressure the air will expand in a nearly explosive way, a behavior, which can be approximated by a complementarity 1, 9. The area of non-smooth mechanics has been estab- lished during the last thirty years by Moreau in Mont- pellier and by Panagiotopoulos in Thessaloniki 6. During the nineties these theories have been transfered and applied to multibody system dynamics 7, 8 and since then furtheron developed in a very concise and rigorous way 4, 5. The research with respect to nu- merical methods is still on the way, because efficient numerical methods are the key for applications with respect to large technical systems 3. The paper will be mainly based on findings of the dissertation 1 and some publication 9. Therefore the description of the new hydraulic theory will be kept short. 2. Modeling hydraulics In order to set up a mathematical model we assume, that the hydraulic system can be considered as a network of basic components. These components are connected by nodes. In conventional simulation programmes these nodes are assumed to be elastic. In the case of rel- atively large volumes this assumption is reasonable whereas for very small volumes incompressible junc- tions, with unilateral or bilateral behavior, are a bet- ter approach. Complex components like control valves can be composed of elementary components like lines, check valves and so forth. In the following a selection of elementary components is considered. It is shown how the equations of motion are derived and how they are put together to form a network. 2.1. Junctions Junctions are hydraulic volumes filled with oil. The volumes may be considered as constant volumes or variable volumes as shown in Fig. 1. Junctions with variable volume are commonly used for hydraulic cylinders. 2.1.1. Compressible junctions Assuming compressible fluid in such a volume leads to a nonlinear differential equation for the pressure p. Springer Nonlinear Dyn (2007) 47:219233 221 Fig. 1 Hydraulic junctions with constant and variable volume Introducing the pressure-dependent bulk modulus E(p) =V dp dV (1) yields a differential equation for the pressure in a con- stant volume p = E V summationdisplay Q i (2) and p = E V (Q 1 A K x) (3) in a variable volume, respectively. A common assump- tion with respect to the fluid properties considers a mixture of linear elastic fluid with a low fraction of air. Fig. 2 shows the calculated specific volume of a mixture of oil and 1% air (at a reference value of 1 bar). For high pressure values the air is compressed to a neglectable small volume whereas the air expands abruptly for low pressure values, see Fig. 2 with the pressure p versus the specific volume v. This figure illustrates also that the curve for the pressure in dependency of the specific volume can be very well approximated by a unilateral characteristic. If we would choose a smooth model we would get stiff differential Equations (2) and (3) for very small volumes V 0. 2.1.2. Incompressible junctions To avoid stiff differential equations for small volumes it is obviously possible to substitute the differential equa- tions by algebraic equations. Assuming a constant spe- cific volume of the incompressible fluid yields for a constant and a variable volume, respectively, the fol- lowing algebraic equations: summationdisplay Q i = 0 respectively summationdisplay Q i A K x K = 0 (4) These equations consider neither the elasticity nor the unilaterality of the fluid properties. A fluid model cov- ering both elasticity and unilaterality is described in Section 2.1.1. In the case of neglectable small volumes the fluid properties can be approximated by a unilateral characteristic. As illustrated in Fig. 2 a unilateral law Fig. 2 Fluid expansion for low pressures Springer 222 Nonlinear Dyn (2007) 47:219233 can be established by introducing a state variable V = integraldisplay t 0 summationdisplay Qd (5) which represents the total void volume in a fluid vol- ume. Obviously this void volume is restricted to be positive, V 0. As long as the pressure value is higher than a certain minimum value p min , the void volume is zero. A void formation starts when the pressure p ap- proaches the minimum value p min . This idealized fluid behavior can be described by a so called corner law or Signorinis law 7. V 0; p 0; V p = 0 (6) The pressure reserve p is defined by p = p p min . By differentiation the complementarity can be put on a velocity level. V = summationdisplay Q i 0 , (7) The equality sign represents the Kirchhoff equation stating that the sum of all flow rates into a volume is equal to the sum of all flow rates out of the volume. If the outflow is higher than the inflow the void vol- ume increases, V 0. Substituting the flow rates Q into a fluid volume by the vector of the velocities in the connected lines and the corresponding areas, v = v 1 v 2 . . . v i W = A 1 A 2 . . . A i (8) yields the junction equation in the unilateral form W T v 0 . (9) It is evident that fluid volumes with non-constant vol- ume can be put also into this form by extending the velocity and area vectors by the velocity and the area of the piston, respectively. As long as the pressure is higher than the minimum value, p 0, the unilateral Equation (9) can be substituted by a bilateral equa- tion W T v = 0. In this case it is necessary to verify the validity of the assumption p 0 because the bilateral constraint does not prevent negative values of p. 2.2. Valves In the following we shall give some examples of mod- elling elementary valves and more complex valves as a network of basic components. Physically, any valve is a kind of controllable constraint, whether the working element be a flapper, ball, needle etc. 2.2.1. Orifices Orifices with variable areas are used to control the flow in hydraulic systems by changing the orifice area. As illustrated in Fig. 3 the pressure drop in an orifice shows a nonlinear behavior. The classical model to calculate the pressure drop Delta1p in dependency of the area A V and the flow rate Q is the Bernoulli equation. Delta1p = 2 parenleftbigg 1 A V parenrightbigg 2 Q|Q| (10) The factor is an empirical magnitude consider- ing geometry- and Reynoldsnumber-depending pres- sure losses. It must be determined experimentally. As long as the valve is open the pressure drop can be calculated as a function of the flow rate and the valve area, Equation (10). As shown in Fig. 3 the character- istic becomes infinitely steep when the valve closes. In most commercial simulation programmes this leads to numerical ill-posedness and stiff differential equations for very small areas. In order to avoid such numeri- cal problems the characteristic for the pressure drop of closed valves can be replaced by a simple constraint Fig. 3 Pressure drop in an orifice Springer Nonlinear Dyn (2007) 47:219233 223 equation. Q = Av = 0 respectively A v = 0 (11) This constraint has to be added to the system equations when the valve closes. In the case of valve opening it has to be removed again. This leads to a time-varying set of constraint equations. In order to solve the system equa- tions one has to distinguish between active constraints (closed valves) and passive constraints (opened valves). The last ones can be removed. The constraint equations avoid stiff differential equations. On the other hand they require to define active and passive sets 4, 7, 8. 2.2.2. Check valves Check valves are directional valves that allow flow in one direction only. It is not worth trying to describe all existing types, so only the basic principle and the mathematical formulation is presented. Figure 4 shows the principle of a check valve with a ball as working element. Assuming lossless flow in one direction and no flow in the other direction results in two possible states: a114 Valve open: pressure drop Delta1p = 0 for all flow rates Q 0 a114 Valve closed: flow rate Q = 0 for all pressure drops Delta1p 0 Again these two states can be described by a corner law Q 0; Delta1p 0; Q Delta1p = 0 . (12) Prestressed check valves with springs show a mod- ified unilateral behavior, see Fig. 5. The pressure drop curve of a prestressed check valve can be split into an ideal unilateral part Delta1p 1 and a Fig. 4 Check valve Fig. 5 Check valve characteristics smooth curve Delta1p 2 considering the spring tension and pressure losses, see Fig. 6 2.2.3. Combined components Many hydraulic standard components are combinations of basic elements. Since the combination of unilateral and smooth characteristics yields either non-smooth or smooth behavior it is worth to consider such compo- nents with a smooth characteristic separately. As an example we consider a typical combination of a throt- tle and a check valve. Figure 7 shows the symbol and the characteristics of both components. Since the flow rate of the combined component is the sum of the flows in the check valve and the throttle, the sum of the flow rates is a smooth curve. In such cases it is convenient to model the combined component as a smooth compo- nent (in the mechanical sense as a smooth force law). 2.2.4. Servovalves As an example for a servovalve we consider a one-stage 4-way-valve. It is a good example for the complexity of the networks representing such components like valves, pressure control valves, flow control valves and related valve systems. Multistage valves can be modelled in Fig. 6 Superposition of unilateral and smooth curves Springer 224 Nonlinear Dyn (2007) 47:219233 Fig. 7 Combination of smooth and non-smooth components a similar way as a network consisting of servovalves and pistons, which themselves are working elements of the higher stage valve. Figure 8 shows the working principle of a 4-way valve. Moving the control piston to the right connects the pressure inlet P with the output B and simultaneously the return T with the output A. If one connects the outputs A and B with a hydraulic cylinder, high forces can be produced with small forces Fig. 8 4-way valve acting on the control piston. The valve works like a hydraulic amplifier. Figure 9 shows a network model of the 4-way valve. The areas of the orifices A V 1 .A V 4 are controlled by the position x of the piston. The orifice areas are as- sumed to be known functions of the position x. The parameter covers a potential deadband. To derive the equations of motion the lines in the network are as- sumed to be flow channels with cross sectional areas A 1 .A 4 . The fluid is incompressible since the vol- umes are usually very small, and the bulk modulus of the oil is very high. The oil masses in the lines are m 1 .m 4 . Denoting the junction pressures with p i and the pressure drops in the orifices with Delta1p i , we get the equations of momentum as m 1 v 1 A 1 p 1 + A 1 p 2 + A 1 Delta1p 1 = 0 m 2 v 2 A 2 p 2 + A 2 p 3 + A 2 Delta1p 2 = 0 m 3 v 3 A 3 p 3 + A 3 p 4 + A 3 Delta1p 3 = 0 m 4 v 4 + A 4 p 1 A 4 p 4 + A 4 Delta1p 4 = 0 (13) Fig. 9 Network model of a 4-way valve Springer Nonlinear Dyn (2007) 47:219233 225 which can be expressed as M v + Wp+ W V Delta1p = W a Delta1p a . (14) where v is the vector of flow velocities, p the vector of junction pressures, Delta1p the vector of pressure drops in the closed orifices and Delta1p a the vector of pressure drops in the open orifices. The mass matrix M = diag(m i )is the diagonal matrix of the oil masses. The matrix W = A 1 A 1 00 0 A 2 A 2 0 00A 3 A 3 A 4 00A 4 is used to calculate the forces acting on the oil masses in the channels resulting from the junction pressures p. The junction equations are given by Q P Q A Q T Q B + A 1 00A 4 A 1 A 2 00 0 A 2 A 3 0 00A 3 A 4 v 1 v 2 v 3 v 4 = 0 (15) which can be written in the form Q in + W T v = 0 . (16) In order to determine the pressure drops Delta1p i one has to distinguish between open and closed orifices to avoid stiff equations, see Section 2.2.1. In case of open ori- fices the pressure drop can be calculated directly sub- ject to the given flow rates and the orifice area, whereas closed orifices are characterized by a constraint equa- tion. Delta1p ai = f (v i , A Vi (x) open orifices i A j v j = 0 closed orifices j (17) The constraint equations for the closed orifices are col- lected to give W T V v = 0 (18) Fig. 10 Coordinates for one-dimensional flow where the number of columns of W V is the number of closed orifices. Note that this matrix has to be updated every time an orifice opens or closes. 2.3. Hydraulic lines Hydraulic lines or hoses are used to connect compo- nents. For long lines the dynamics of the compress- ible fluid has to be taken into account. In order to get a precise system model, it is necessary to investigate pressure wave phenomena as well as the pipe friction. The pipe friction is rather complicated since the veloc- ity profile is not known a priory. In the case of laminar flow it is possible to derive analytical formulas for a uniform fluid transmission line in the Laplace domain. The so-called 4-pole-transfer-functions relate the pres- sure and the flow at the input and at the output of the line in dependency of Bessel functions. Many attempts have been made to approximate the transfer functions with rational polynomial functions which can be re- transformed into the time domain. Unfortunately the form of the equations of these models is not compati- ble with the equations in the framework of this paper, because the coupling with constraint equations might lead to numerical instability due to violation of the prin- ciple of virtual work. In the following a time domain modal approxima- tion is presented. This model can be extended to cover frequency dependent friction as well. The starting point are the linearized partial differential equations for one- dimensional flow. The coordinates are shown in Fig. 10. Partial derivatives of a arbitrary coordinate q are de- noted by q t = q and q x = q prime , respectively. The mass balance p + E A Q prime = 0 (19) Springer 226 Nonlinear Dyn (2007) 47:219233 with the flow rate Q = Au and the introduced state variable x = 1 A integraldisplay t 0 Qd ; x =