畢 業(yè) 設 計（論文）題目：履帶拖拉機無級變速器設計（操縱機構設計）姓 名: 院 系: 專 業(yè): 指導教師: 摘要拖拉機工作條件復雜，外界負荷復雜多變，要求發(fā)動機或變速器能適時的改 變轉矩的大小或轉速，以保證拖拉機的動力性和經濟性。傳統變速箱雖能通過換擋達到一定的要求，但其檔位有限，無法實現無級變速。液壓機械無級變速器（ HMCVT）是一種液壓功率流與機械功率流并聯的新型轉動裝置，液壓機械無級變速器是綜合了機械傳動高效率和液壓傳動無級變速兩方面優(yōu)點的新型傳動機構。液壓機械無級傳動是一種多功率流傳動系統，它將功率分為液壓和機械兩路傳遞即功率分流，分流機構分流后液壓馬達在正向和反向最大速度之間來回無級變速。其每一個行程和行星齒輪機構的一種工況相配合，最后，兩路匯合成由若干無級調速段相銜接并組逐段升高的全程無級輸出速度。液壓元件只負擔最大功率的一部分，其他功率都由機械路傳遞。這相當于將液壓無級變速功率擴大，傳動總效率相對于液壓傳動也顯著提高，和液力機械傳動相比，裝載量最大可提高 30%，燃油經濟性最大可提高 25%。其特點是通過機械傳動實現功率轉遞，通過液壓機械相結合實現無級變速。目前，國外先進的拖拉機，工程車輛已經采用液壓無級變速器。馬達的最高轉速對應著該段的末速度，當這段的末速度等于后一段的初速度及后一段初速度對應馬達最高轉速位置。此液壓機械無級變速器必須與發(fā)動機合理匹配才能發(fā)揮其優(yōu)勢。匹配的關鍵是根據各種路況和發(fā)動機特性調節(jié)變速器的傳動比，使發(fā)動機工作在最佳狀態(tài)。 我國是一個人均能源，資源貧乏的發(fā)展中國家，提高燃油的經濟性尤為重要。目前，我國在這方面的研究處于理論研究階段。關鍵詞：功率分流，匹配,燃油的經濟性。ABSTRACTTractor working conditions complicated complex and ever-changing external load. Engine request or timely transmission of torque to change the size or speed to ensure that the tractor power and economy. Although traditional gearbox through shifting to reach a certain standard, but its gear is limited and they can not achieve CVT.Hydraulic machinery CVT (HMCVT) is a power flow of hydraulic and mechanical power flow parallel to the new rotation device , hydraulic machinery CVT is a synthesis of highly efficient mechanical transmission and hydraulic drive CVT merits of the two new drive institutions. Hydro-Mechanical - drive is a multi-stream transmission, power will be divided into two hydraulic and mechanical way that the power transfer streaming streaming agencies triaged hydraulic motor in forward and reverse maximum speed between both CVT. Each of its itinerary and a planetary gear mechanism for a state match, finally, Road converge into two by a number of variable speed converge and the group has to absolutely no higher level of output speed changes. Hydraulic Components burden only part of the maximum power, the other by mechanical power transmission path. This will be the equivalent of continuously variable hydraulic power expansion drive efficiency relative to the total hydraulic transmission has improved significantly. hydraulic and mechanical transmission, the loading capacity can be increased by 30%, fuel economy can be increased 25%. Its characteristics are achieved through mechanical transmission transmit power through the combination of hydraulic machinery to achieve CVT.Currently, foreign advanced tractors, construction vehicles using hydraulic CVT. Motor corresponding to the maximum speed of the speed at the end, When this speed to the end after a period of the early speed and after a period of initial velocity corresponding maximum speed motor position. This hydraulic mechanical CVT engine with a reasonable match to play to their strengths. Matching is the key to all kinds of traffic regulation and the engine characteristics of the transmission ratio transmission, the engine work in the best condition.China is a per capita energy and resource-poor developing countries, to increase fuel economy is particularly important. Currently, our research in this area in theoretical research stage.KEY WORD : power streaming CVT, matching ,fuel economy.目 錄第一章 緒論. 1第二章 液壓機械無級變速器傳遞方案的確定.2§2.1 液壓機械無級傳動的原理及特點2§2.1.1 液壓傳動原理2§2.1.2 液壓傳動特點3§2.2 液壓機械無級變速器傳遞方案的選擇3第三章 液壓泵－液壓馬達調速油路的設計6§3.1 變量泵與定量馬達排量的確定 .6§3.1.1 變量馬達—定量泵所組成的油路6§3.1.2 補油泵的選擇 .8§3.1.3 液壓油及油管的選擇9§3.2 液壓油路壓力損失的確定 9§3.2.1 液壓油流動狀態(tài)的確定 9§3.2.2 油路沿途壓力損失的計算 9§3.2.3 局部壓力損失10§3.3 油箱尺寸的確定 10§3.4 液壓元件的選擇.11第四章 液壓機械無級變速器液壓控制油路設計13§4.1 油路設計.13§4.1.1 冷卻與潤滑油路.13§4.1.2 液壓元件的選擇14§4.2 液壓機械無級變速控制原理.14§4.2.1 經濟性換擋. .15§4.2.2 動力性換擋 17第五章 結論.21參考文獻.22致謝.24