527 履帶拖拉機變速器改進設(shè)計Ⅱ（有cad圖）

527 履帶拖拉機變速器改進設(shè)計Ⅱ（有cad圖）,527,履帶拖拉機變速器改進設(shè)計Ⅱ（有cad圖）,履帶,拖拉機,變速器,改進,改良,設(shè)計,cad 履帶拖拉機變速器改進設(shè)計Ⅱ 摘 要 本次設(shè)計任務(wù)為：履帶拖拉機變速器的改進設(shè)計。 變速箱的結(jié)構(gòu)對拖拉機的動力性、經(jīng)濟性、操縱的可靠性與輕便性、工作噪聲等都有直接影響。變速箱主要用來改變發(fā)動機傳到驅(qū)動輪上的轉(zhuǎn)矩和轉(zhuǎn)速，目的是在起步、爬坡、轉(zhuǎn)彎、加速等各種行駛工況下，使汽車獲得不同的牽引力和速度，同時使發(fā)動機在最有利的工況范圍工作，設(shè)有空檔和倒檔，并設(shè)有動力輸軸。 為適應(yīng)農(nóng)業(yè)耕作的復(fù)雜工況，要求變速箱采用多檔位,以使變速箱有較寬的速比范圍，以使拖拉機能高效率高質(zhì)量地完成各種作業(yè)。該變速器采用手動嚙合套換檔機構(gòu)，空間三軸布置方式，結(jié)構(gòu)緊湊。 本次設(shè)計按照傳統(tǒng)設(shè)計方法，本著半經(jīng)驗半理論的設(shè)計原則通過類比法確定方案，參照已有變速箱結(jié)構(gòu)，最后以機械零件的強度和剛度理論對確定的形狀和尺寸進行必要的計算和校核，以滿足約束條件，進而縮短設(shè)計周期，降低設(shè)計成本。 關(guān)鍵詞：拖拉機，變速箱，嚙合套，改進設(shè)計 IMPROVED DESIGN Ⅱ OF TRACKED TRACTOR TRANSMISSION ABSTRACT This design is an improving design of the tractor transmission. The structure of the transmission has direct effect on the tractor’s traction performance and economy performance as well as its reliability, working noise and so on. Transmission is mainly used to change the engine torque and speed reached on the driving wheel, the aim is to acquire different traction and speed in various driving conditions like starting, climbing, turning and accelerating. At the same time the engine can work in optimum condition. The transmission has reverse gear ，zero gear and power transmission shaft. To meet the complex farming conditions, the transmission should have a multi-gear so that the transmission speed ratio can be changed in a wide scope. Then the tractor can complete all kinds of operation efficiently and high-quality. The transmission adopts the manual shift meshing sets, triaxial space layout. And its structure is compact. The design of transmission uses the traditional design method. Based the semi-empirical and semi-theoretical design principles, the drive scheme is determined by analogy. In order to meet the conditions, shorten the design cycle and reduce design costs, the shape and size of transmission are calculated and checked by the mechanical parts strength and stiffness theory. Key words: tractor, transmission, meshing sleeve, improved design 符 號 說 明 發(fā)動機標定功率， 發(fā)動機標定轉(zhuǎn)速， 傳動系總傳動比 履帶驅(qū)動輪半徑， 拖拉機理論工作速度， km/h 變速器的傳動比 中央傳動比 最終傳動比 各檔之間的公比 A 中心距， T 軸及軸所承受的轉(zhuǎn)矩， 最大地面驅(qū)動力， 地面支反力， 附著系數(shù) 整車總質(zhì)量， g 重力加速度， 中心距系數(shù) m 模數(shù)， 彎曲應(yīng)力， 彎矩， 軸承基本額定壽命用小時來表示， 當(dāng)量動載荷， 壽命指數(shù)，球軸承=3，滾子軸承=10/3 目 錄 第一章 前言............................................1 第二章 變速箱的結(jié)構(gòu)分析................................3 §2.1概述.....................................3 §2.2 變速箱的總體結(jié)構(gòu)分析.......................3 §2.2.1 傳動機構(gòu)布置方案分析 .......................4 §2.2.2 零、部件機構(gòu)方案分析.......................5 §2.3 變速箱的總體結(jié)構(gòu)方案的確定.................6 第三章 變速箱主要參數(shù)的確定...........................7 §3.1傳動系傳動比的計算...........................7 §3.1.1 傳動系總傳動比的計算........................7 §3.1.2 總傳動比與各部件間傳動比的關(guān)系..............7 §3.2 變速箱各檔位傳動比的初步確定..................8 §3.2.1 理論車速的分段及對應(yīng)的傳動比................8 §3.2.2 變速箱各區(qū)段傳動比的確定....................8 §3.3 中心距和模數(shù)的確定........................10 §3.3.1 中心距A的確定.............................11 §3.3.2 模數(shù)m的確定..............................11 §3.4 變速箱各傳動齒輪齒數(shù)的確定...................11 §3.4.1 傳動齒輪齒數(shù)的初步確定.....................11 §3.4.2 齒數(shù)及傳動比的最終確定.....................13 §3.4.3 8+4檔變速箱各檔的速比和速度..............13 §3.5 本章小結(jié)..................................14 第四章 齒輪的設(shè)計計算.................................15 §4.1概述.........................................15 §4.2齒輪主參數(shù)的選擇.............................15 §4.2.1 齒輪副中心距...............................15§4.2.2 齒形角.....................................15 §4.2.3齒寬系數(shù)..................................15 §4.2.4 齒輪基本參數(shù)..............................15 §4.2.5 變位齒輪參數(shù)的確定.........................17 §4.3 齒輪強度的校核.................................17 §4.3.1 拖拉機齒輪常用的加工方法..................18 §4.3.2許用彎曲應(yīng)力的確定.........................18 §4.3.3 輪齒彎曲應(yīng)力的求解.......................18 §4.3.4 齒輪齒寬的確定...........................19 第五章 軸的設(shè)計計算...........................20 §5.1軸結(jié)構(gòu)的初步選定...........................20 §5.2 軸的強度校核...............................21 §5.2.1軸T1的強度校核..........................21 §5.2.2軸T2的強度校核..........................26 §5.2.3軸T3的強度校核..........................30 §5.3 本章小結(jié)................................34 第六章 軸承的選用和壽命計算...........................35 §6.1軸承的選用.................................35 §6.2滾動軸承的壽命的計算........................35 §6.2.1 軸承的平均轉(zhuǎn)速............................35 §6.2.2軸承的基本額定壽命........................36 §6.3本章小結(jié).................................37 第七章 結(jié) 論........................................38 參考文獻...............................................39 致謝...................................................40 V