【正文】 三、預(yù)選氣動(dòng)式操縱機(jī)構(gòu) 為了改善重型貨車組合式變速器的操縱輕便型，副變速器多采用預(yù)選氣動(dòng)式操縱機(jī)構(gòu)換檔，常見的有機(jī)械式和電控式。 α錐面半錐角 鎖環(huán)式慣性同步器 細(xì)牙螺旋槽 滑塊 結(jié)構(gòu) 滑塊 鎖環(huán) 結(jié)合齒圈 原理 定位銷、滑塊 鎖環(huán) 結(jié)合齒圈 1齒厚 2. 鎖銷式慣性同步器 摩擦錐盤 摩擦錐環(huán) 定位銷 結(jié)合套 鋼球 定位銷 鎖銷 直徑較大的摩擦錐面，可產(chǎn)生較大摩擦力矩縮短同步時(shí)間。 12 = :1 Rev. Gear, Driving Rev. Gear, Driven 5Rev. Synchro. Shifted to Rev. Rev. Idler Gear Other Reverse Types Some transaxles construct the 12 synchronizer sleeve with the reverse gear teeth surrounding it. The reverse idler gear is shifted into mesh with the reverse drive gear and the driven gear on the synchro. Sleeve. This is difficult to illustrate because the idler gear and shaft are positioned behind the other gears. Rev. Idler Gear Rev. Drive Gear 12 Synchro. + 1st amp。 20 or 2:1. The blue gear will have twice the torque but onehalf the speed as the green gear. Input: 20 Teeth Output: 40 Teeth Gear Types The most mon gear types are Spur (left) and Helical (right) gears. Spur gears have the teeth cut parallel to the shaft. The teeth of a helical gear are cut at an angle. A helical gear runs quieter, costs more, and generates a side thrust under load. Spur Gears Helical Gears ? 2）通過增加齒輪傳動(dòng)的對(duì)數(shù)，以實(shí)現(xiàn)倒檔。 ? 綜合式變速器： 由液力變矩器和行星齒輪式變速器組成，傳動(dòng)比可在幾個(gè)范圍內(nèi)連續(xù)變化。 Speed Gears amp。 Synchronizers A synchronizer assembly normally has two speed gears, one on each side of it. The speed gears float on the main shaft. The synchronizer sleeve engages the clutching teeth of a speed gear to transfer its motion to the shaft. 12 Synchro. 34 Synchro. 5Rev. Synchro. 3rd Speed Gear 2nd Speed Gear 5th Speed Gear 1st Speed Gear Reverse Speed Gear 6Speed Main Shaft 34 Synchro. 12 Synchro. 56 Driven Gear Rev. Synchro. Output Speed Gear Journals: 3rd 2nd 1st Reverse This mainshaft has 3 splined areas that connect to the synchronizer hubs, a set of splines for the 56 fixed/driven gear, 1 set of output splines for the drive shaft slip joint. And 4 smooth journals for the speed gears. Fixed Gears The main drive gear and cluster gears are normally made as part of their shaft. These are the driving gears for each of the gear ranges. Shifting Gears Most SUV and pickup transmissions incorporate the shift mechanism into the the top of the unit. Movement of the gear shit lever will move one of the shift forks connected to the synchronizer sleeve. Shift Lever Shift Rail Shift Fork Shift Detents Most detents are springloaded balls (red) that are pushed into one of two or three notches in a shift rail or cam. They are used to hold the shift rail in an exact position which places the synchro. sleeve or gear in an exact position. The center shift rail detents are in back of the rail. Detent Ball Detent Spring Shift Rail Shift Fork Shift Interlocks This 5speed transmission has three shift rails that transmit motion from the shift lever to the shift forks. When one of the rails is moved from neutral, the plugs are moved sideways to lock the other rails in place Shift Rails Plug Pin Plug Neutral If each of the synchronizers assemblies is in neutral and the reverse idler gear is not in mesh, power is not able to get from the speed gears to the main shaft. The input shaft, cluster gear, and speed gears rotate but not the main shaft. All Synchros. In neutral, center position Neutral In neutral with the clutch engaged, the input shaft will spin, but there will be no power transferred. Input from clutch Output to drive shaft Neutral power flow 5Speed gearbox Double Reduction Manual transmission gear ratios are effected by two gear sets. The first (input) is the ratio between the main drive gear and cluster gear. The second is the ratio between the drive and driven gears for each gear range. 15 Tooth Main Drive Gear 20 Tooth Cluster Gear 1st Gears Input reduction: 20 247。 ? 自鎖 ? 互鎖 ? 倒擋鎖 ? 選檔鎖 ? 1）自鎖裝置 ? 組成：自鎖鋼球和自鎖彈簧； 作用：保證換檔到位 。 ?原因： 避免中、后橋在低檔時(shí)（輸出轉(zhuǎn)矩較大）過載。 組成：變速桿、撥塊、撥叉軸和撥叉及安全裝置 位置：變速箱上蓋或側(cè)蓋內(nèi) 特點(diǎn)：結(jié)構(gòu)簡(jiǎn)單，操縱方便 1．選檔換檔機(jī)構(gòu) ? 組成：變速桿、撥塊、撥叉軸和撥叉等； ? 作用：完成換檔的基本動(dòng)作。汽車行駛中可能會(huì)因振動(dòng)等原因造成接合套與齒圈脫離嚙合，即發(fā)生自動(dòng)跳檔。 二、兩軸式變速器 Manual Transaxle Operati