無級(jí)變速器電液控制系統(tǒng)研究開發(fā)畢業(yè)論文(已修改)

　

【正文】 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。CVT變速器能夠?qū)崿F(xiàn)傳動(dòng)速比的自動(dòng)連續(xù)變化，滿足駕駛者的各種駕駛意圖，有利于實(shí)現(xiàn)汽車傳動(dòng)系統(tǒng)與發(fā)動(dòng)機(jī)的最佳匹配與控制，具有操縱簡(jiǎn)便、駕駛舒適、平順、性能良好等特點(diǎn)，是理想的汽車變速裝置。金屬帶式CVT具有較大的功率傳遞容量、較高的傳動(dòng)效率、較長的壽命等特點(diǎn)，是目前世界上應(yīng)用最廣泛的無級(jí)變速器。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。隨著計(jì)算機(jī)的發(fā)展，采用數(shù)字技術(shù)控$lJcv39。r是必然趨勢(shì)。因此針對(duì)CVT電液控制系統(tǒng)研究和開發(fā)數(shù)字比例控制元件對(duì)于提高CVT控制性能和降低成本有很好的經(jīng)濟(jì)和社會(huì)效益。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。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。(2)分析了金屬帶式CVT的基本結(jié)構(gòu)和變速原理，詳細(xì)闡述了其關(guān)鍵零部件， 并且對(duì)會(huì)屬帶式CVT的控制問題做了研究。(3)針對(duì)日益廣泛應(yīng)用的比例控制技術(shù)提出了改進(jìn)的電液控制系統(tǒng)，從而將數(shù)字比例控制技術(shù)應(yīng)用至tlCVT中。并介紹了高速開關(guān)閥的結(jié)構(gòu)承1工作原理。(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。(5)對(duì)數(shù)字調(diào)壓閥進(jìn)行了特性試驗(yàn)，并將數(shù)字調(diào)壓閥應(yīng)用至IJCVT電液控制系統(tǒng)中，在現(xiàn)有的試驗(yàn)條件下進(jìn)行了臺(tái)架試驗(yàn)，試驗(yàn)結(jié)果表明，該電液控制系統(tǒng)效果良好，具有一定的可行性，但由于試驗(yàn)條件的限制，未能進(jìn)行實(shí)車試驗(yàn)。本文的主要?jiǎng)?chuàng)新之處在于通過仿真分析和試驗(yàn)，設(shè)計(jì)開發(fā)了適用于CVT電液控制系統(tǒng)的數(shù)字調(diào)壓閥，從而將數(shù)字比例控制技術(shù)應(yīng)用于CVT電液控制系統(tǒng)中。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。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，，，。!。，。，垂堡竺童堊皇童壘!：i!絲墼壘至壘，一，一。，，：． 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。除了文中