無級變速器電液控制系統研究開發畢業論文-全文預覽

　　

【正文】 為后來所采用，這就是帶傳動式(Belt Drive)或鏈傳動式(chainDrive)cVT的前身。由于CVT可以實現傳動比的連續改變，從而得到傳動系與發動機工況的最佳匹配， 提高整車的燃油經濟性和動力性，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裝置。這些來自國家政府機構以及社會各個方面的壓力，迫使汽車生產商采取措施以滿足這些法規的要求.。而全球數以千萬計的汽車已經成為能源消耗和環境污染的一個主要的因素。汽車工業歷經百余年取得了巨大的發展，究其原因，主要有兩點：首先是科學技術的不斷進步，給汽車工業的發展提供了必要的物質條件；其次是汽車工業本身為了不斷適應各個時期的社會背景(能源危機和環境污染等)，滿足人們對汽車使用性能的更高要求，在技術上不斷改革、創新。本人授權湖南大學可以將本學位論文的全部或部分內容編入有關數據庫進行檢索，可以采用影印、縮印或掃描等復制手段保存和匯編本學位論文。除了文中特別加以標注引用的內容外，本論文不包含任何其他個人或集體已經發表或撰寫的成果作品。關鍵詞：金屬帶式無級變速器；cvr；電液控制系統：數字比例控制；數字閥。(4)自主研制了步進式數字調壓閥，建立了數字調壓閥的數學模型并進行了仿真分析，锝到了各靜參數對系統壓力的影響規律。本文共分為五章，主要內容如下：(1)在參閱了國內外大量文獻的基礎上，系統地介紹了金屬帶式無級變速器的發展歷史、當的的技術狀況以及發展前景。隨著計算機的發展，采用數字技術控$lJcv39。碩士學位論文無級變速器電液控制系統研究開發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，該系統結構復雜，對油質要求十分嚴格， 控制損失較大，可移植性差，致使價格昂貴，限制了它的普及應用。本文正是從上述需求出發，針對金屬帶式無級變速器的電液控制系統，探討了CVT的控制原理和數字比例控制技術在CVT上的應用。并介紹了高速開關閥的結構承1工作原理。試驗表明，數字調壓閥有較高的控制精度和可靠性，數字比例控制技術能降低CVT 電液控制系統的成本，提高產品質量，從而提高CVT的競爭力，因而數字比例控制的發展前景十分廣闊。：． 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湖南大學學位論文原創性聲明本人鄭重聲明：所呈交的論文是本人在導師的指導下獨立進行研究所取得的研究成果。作者簽名： 喪牝日期：叼年3月膀日學位論文版權使用授權書本學位論文作者完全了解學校有關保留、使用學位論文的規定，同意學校保留并向國家有關部門或機構送交