525 履帶拖拉機變速器改進設計Ⅰ（有cad圖）,525,履帶拖拉機變速器改進設計Ⅰ（有cad圖）,履帶,拖拉機,變速器,改進,改良,設計,cad 履帶拖拉機變速器改進設計Ⅰ 摘 要 變速箱的結(jié)構對拖拉機的動力性、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，設有空檔和倒檔，并設有動力輸軸。 為適應農(nóng)業(yè)耕作的復雜工況，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，空間三軸布置方式，結(jié)構緊湊。 本次設計按照傳統(tǒng)設計方法，本著半經(jīng)驗半理論的設計原則通過類比法確定方案，參照已有變速箱結(jié)構，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，進而縮短設計周期，降低設計成本。 關鍵詞：拖拉機，變速箱，嚙合套，改進設計 IMPROVED DESIGNⅠOF TRACTOR TRANSMISSION ABSTRACT 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 A 變速箱中心距 mm m 齒輪模數(shù) G 重量 N T 轉(zhuǎn)矩 Nm f 摩擦系數(shù) D 軸的直徑 mm Z 齒數(shù) B 齒輪寬度 D 直徑 E 彈性模量 傳動比 發(fā)動機最大輸出扭矩 機械效率 齒輪齒數(shù) 節(jié)點處壓力角 彎曲應力 接觸應力 圓周力 徑向力 軸向力 I 慣性矩 目 錄 第一章 前言..........................................1 第二章 變速器結(jié)構設計..................................2 §2.1概述.........................................2 §2.2變速器布置方案分析.............................2 §2.2.1 變速器傳動機構的方案分析....................2 §2.2.2 變速器零部件結(jié)構分析........................4 第三章 變速器基本參數(shù)的確定............................5 §3.1傳動比的確定................................5 §3.2 中心距計算.................................5 §3.3齒輪參數(shù)...................................5 第四章 齒輪的設計和計算..............................8 §4.1齒輪的設計思想.................................8 §4.2 齒輪設計及變位計算............................9 第五章 齒輪的強度校核................................15 §5.1校核二軸一擋齒輪...............................15 §5.2 校核一軸一擋齒輪..............................16 第六章 軸的校核.....................................18 §6.1軸的受力分析.................................18 §6.2 軸剛度校核...................................18 §6.2.1 一軸剛度校核...............................18 §6.2.2 二軸剛度校核...............................19 §6.3 軸強度校核.....................................20 §6.3.1 一軸強度校核...............................20 §6.3.2 二軸強度校核...............................23 第七章 軸承選擇的壽命計算.............................25 第八章 鍵的選擇及校核...............................27 第九章 變速器操縱機構.................................29 第十章 結(jié)論...........................................33 參考文獻...............................................34 致謝...................................................36 V