【正文】 為后來所采用，這就是帶傳動(dòng)式(Belt Drive)或鏈傳動(dòng)式(chainDrive)cVT的前身。由于CVT可以實(shí)現(xiàn)傳動(dòng)比的連續(xù)改變，從而得到傳動(dòng)系與發(fā)動(dòng)機(jī)工況的最佳匹配， 提高整車的燃油經(jīng)濟(jì)性和動(dòng)力性，改善駕駛員的操縱方便性和乘員的乘坐舒適性， 所以它是理想的汽車傳動(dòng)裝置。這些來自國家政府機(jī)構(gòu)以及社會(huì)各個(gè)方面的壓力，迫使汽車生產(chǎn)商采取措施以滿足這些法規(guī)的要求.。而全球數(shù)以千萬計(jì)的汽車已經(jīng)成為能源消耗和環(huán)境污染的一個(gè)主要的因素。汽車工業(yè)歷經(jīng)百余年取得了巨大的發(fā)展，究其原因，主要有兩點(diǎn)：首先是科學(xué)技術(shù)的不斷進(jìn)步，給汽車工業(yè)的發(fā)展提供了必要的物質(zhì)條件；其次是汽車工業(yè)本身為了不斷適應(yīng)各個(gè)時(shí)期的社會(huì)背景(能源危機(jī)和環(huán)境污染等)，滿足人們對(duì)汽車使用性能的更高要求，在技術(shù)上不斷改革、創(chuàng)新。本人授權(quán)湖南大學(xué)可以將本學(xué)位論文的全部或部分內(nèi)容編入有關(guān)數(shù)據(jù)庫進(jìn)行檢索，可以采用影印、縮印或掃描等復(fù)制手段保存和匯編本學(xué)位論文。除了文中特別加以標(biāo)注引用的內(nèi)容外，本論文不包含任何其他個(gè)人或集體已經(jīng)發(fā)表或撰寫的成果作品。關(guān)鍵詞：金屬帶式無級(jí)變速器；cvr；電液控制系統(tǒng)：數(shù)字比例控制；數(shù)字閥。(4)自主研制了步進(jìn)式數(shù)字調(diào)壓閥，建立了數(shù)字調(diào)壓閥的數(shù)學(xué)模型并進(jìn)行了仿真分析，锝到了各靜參數(shù)對(duì)系統(tǒng)壓力的影響規(guī)律。本文共分為五章，主要內(nèi)容如下：(1)在參閱了國內(nèi)外大量文獻(xiàn)的基礎(chǔ)上，系統(tǒng)地介紹了金屬帶式無級(jí)變速器的發(fā)展歷史、當(dāng)?shù)牡募夹g(shù)狀況以及發(fā)展前景。隨著計(jì)算機(jī)的發(fā)展，采用數(shù)字技術(shù)控$lJcv39。碩士學(xué)位論文無級(jí)變速器電液控制系統(tǒng)研究開發(fā)摘要自第一輛汽車問世以來，人們就致力于改善汽車變速器的性能。早期的CVT均采用電液伺服控制系統(tǒng)，該系統(tǒng)結(jié)構(gòu)復(fù)雜，對(duì)油質(zhì)要求十分嚴(yán)格， 控制損失較大，可移植性差，致使價(jià)格昂貴，限制了它的普及應(yīng)用。本文正是從上述需求出發(fā)，針對(duì)金屬帶式無級(jí)變速器的電液控制系統(tǒng)，探討了CVT的控制原理和數(shù)字比例控制技術(shù)在CVT上的應(yīng)用。并介紹了高速開關(guān)閥的結(jié)構(gòu)承1工作原理。試驗(yàn)表明，數(shù)字調(diào)壓閥有較高的控制精度和可靠性，數(shù)字比例控制技術(shù)能降低CVT 電液控制系統(tǒng)的成本，提高產(chǎn)品質(zhì)量，從而提高CVT的競(jìng)爭(zhēng)力，因而數(shù)字比例控制的發(fā)展前景十分廣闊。：． Abstract From the appearance of the automobile，People have made great efforts to improve the performance of automotive transmission．The continuously variable transmission(CVT)can change speed ratio automatically and continuously，sarisfy the driver’S every driving purpose，propitious to achieve the optimal matching and control of power train，and it is regarded as the ideal automobile transmission with the advantages of easy operation，fortable and smooth driving，excellent performance．Metal V—belt type CVT has such merits as bigger power transferring capacity，transmission efficiency and longer life，SO it has been the most widely used． Early CVT was always controlled by the mechanical—hydraulic servo technology，its response is quick and its precision high，but its controlling module plicated and power loss big．Besides，it is sensible of oil pollution，and needs developing for a certain type as it can’t be applied to other CVT，the development of such controlling module is SO expensive that it hasn’t been widely used．It is inevitable for CVT to adopt digital controlling technology with the development of the puter．Digital controlling technology bines both the superiority of big hydraulic power—weight ratio and flexible electronic—puter controlling，SO it develops quickly in all industry fields．Digital controlling technology can meet the requirement of dynamic and static performance of CVT，and has such merits as low cost，strong anti—pollution ability，handling performance，easy automobile，simple structure and low energy consumption．On the whole，it is beneficial to research and develop the digital electro—hydraulic controlling module to improve the performance of CVT and reduce its cost for economical and social benefit． Based on the demands above and aiming at electro—hydraulic controlling system of metal belt CVT，this paper is to research the controlling theory and digital proportional controlling technology on CVT．This paper has five chaprers，and the main contents are following： (1) Based on lots of professional documents，the dissertation reviews the development process and the technique of CVT briefly．Through the parison with other transmission，showing that the metal pushing V—Belt type CVT can meet the currently demand of drivability，economics and emission etc，and stating that the CVT is the ideal transmission which will be the developing tendency for the transmission of passenger car．In the paper the background and the necessity碩士學(xué)位論文of this theme in science and practice are given． (2)The structure and principle of operation of CVT were introduced．The key sections of the transmission are introduced．The main research issue is the control method that include three point：the clamp force control，the ratio control and the clutch contr01．Only when the three aspects are all in optimum state the vehicle function quota can elaborate pletely． (3)The advanced digital proportional electro—hydraulic controlling technology was applied on CVT to improve the controlling system of CVT．The structure and principle of highspeed on—off valve were introduced． (4)The digital valve were designed，and the math model of the digital valve built and analyzed through puter simulation with Matlab．The analysis shows that the digital valve has fine performance on dynamic and static state，and as the result，it can meet the requirement of electro—hydraulic controlling system of CVT． (5)Design of experiment was applied on the application parameters of the digital valve owing to the fluctuation of hydraulic pressure．In the end，we did bench test under the test condition we have to demonstrate the control—theory right or not． The test included constant speed ratio follow and step speed ratio follow，from the test resule we can see this control system effect all right and possess definite feasibility，but owing to limitation of test condition，we can’t proceed the next bench test and autotest．The result shows that the digital valve can meet the requirement of ratio controlling of CVT． The mostly innovation of the paper is to develop a step motor controlled digital valve suitable for electro—hydraulic controlling system of CVT and apply digital proportional controlling technology tO CVT．The test result shows that the digital valve has high controlling accuracy and reliability，and that digital proportional controlling technology can reduce the cost of electro—hydraulic controlling system．At the same time，it can improve the quality and the petitiveness of CVT，SO the digital proportional controlling technology has a bright future． Key Words：Metal belt VType Continuously Variable Transmission；CVT； Electro—hydraulic Controlling System；Digital Proportional Controlling Technology：Digital Valve湖南大學(xué)學(xué)位論文原創(chuàng)性聲明本人鄭重聲明：所呈交的論文是本人在導(dǎo)師的指導(dǎo)下獨(dú)立進(jìn)行研究所取得的研究成果。作者簽名： 喪牝日期：叼年3月膀日學(xué)位論文版權(quán)使用授權(quán)書本學(xué)位論文作者完全了解學(xué)校有關(guān)保留、使用學(xué)位論文的規(guī)定，同意學(xué)校保留并向國家有關(guān)部門或機(jī)構(gòu)送交