28馬力輪式拖拉機(jī)變速箱設(shè)計(jì)（含CAD圖紙）

28馬力輪式拖拉機(jī)變速箱設(shè)計(jì)（含CAD圖紙）,28,馬力,輪式拖拉機(jī),變速箱,設(shè)計(jì),cad,圖紙 28馬力輪式拖拉機(jī)變速箱設(shè)計(jì)摘 要為了獲得適合各種農(nóng)業(yè)工作的不同速度和牽引力，我們就必須通過變速箱來降低從發(fā)動(dòng)機(jī)傳出的較快的轉(zhuǎn)速并將動(dòng)力傳遞給驅(qū)動(dòng)裝置來行走或作業(yè)。在田間或公路運(yùn)輸時(shí)要求有較快的行駛速度，但是在田間作業(yè)和工程施工時(shí)則需要較慢的速度和較大的牽引力。為了實(shí)現(xiàn)這種目的，大部分必要的減速通常通過變速箱總成中的滑移齒輪來實(shí)現(xiàn)，進(jìn)一步的減速則是通過中央傳動(dòng)和最終傳動(dòng)的大、小齒輪的嚙合來實(shí)現(xiàn)的。在現(xiàn)代的拖拉機(jī)中，拖拉機(jī)不僅被用來田間作業(yè)，還用來搞運(yùn)輸、粉碎飼料等。為了滿足不同工況的需要和提高經(jīng)濟(jì)性，一般都是多擋位的，本設(shè)計(jì)采用8個(gè)前進(jìn)擋的設(shè)計(jì)方案。對(duì)于拖拉機(jī)來說，一般變速箱總成都采用直齒圓柱齒輪以降低成本，則用滑移齒輪前后移動(dòng)與中間軸上齒輪嚙合以獲得需要的速度。為了滿足拖拉機(jī)的中耕和其它作業(yè)需要，例如耕地、耙地、工程施工等。都需要在設(shè)計(jì)中設(shè)計(jì)動(dòng)力輸出裝置，通過動(dòng)力輸出軸將從發(fā)動(dòng)機(jī)傳來的扭矩傳到拖拉機(jī)后部，以帶動(dòng)各種機(jī)具工作。關(guān)鍵詞： 拖拉機(jī)， 變速箱， 滑移齒輪， 動(dòng)力輸出軸TRANSMISSION DESIGN OF 28 HP TRACTORABSTRACTWe must reduce the relatively fast speed of the engine and transmit its power to the driving menbers to obtain suitable speeds and pulling power for the different farm jops. You may want a fst forward speed for hauling form the field or on the highway but a much slower fortions.Aslo,you msut have some means of reversing the direction of rotation of the driving members.Much of the necessry speed reduction is accomplished by the sliding(speed-changing)gears of the assembly which is ususlly called the “transmission.”Further reduction is secured at the differential and by the final drive pinions and bull gears.In todays tractors there are still more gear combingations giving more forward speeds; these are needed for the many operations now performed with farm tractors.You select the speed you want by shifting one of the sliding gears,which are splined to be transmission shaft.With the gear shift lever,you can move then forward or backward;you can mesh any certain sliding gear with its mating gear on the counter-shaft.Live power take-off is an asset with many p.t.o.driven machine .KEY WORDS： tractor, transmission，sliding gears，power take-off 目 錄第一章 前 言1第二章 結(jié)構(gòu)分析與設(shè)計(jì)2 2.1 概述2 2.1.1變速箱的功用、要求22.2 布置方案的分析與確定22.2.1傳動(dòng)機(jī)構(gòu)的方案分析與確定22.2.2 變速箱零、部件結(jié)構(gòu)分析與確定32.2.3 發(fā)動(dòng)機(jī)和輪胎選擇6第三章 變速器主要參數(shù)的確定73.1 概述73.2 變速器主要參數(shù)的確定73.3 常嚙合齒輪參數(shù)的確定10第四章 變速器圓柱齒輪的結(jié)構(gòu)和設(shè)計(jì)124.1 齒輪的變位124.2 齒輪的強(qiáng)度計(jì)算13第五章 中央傳動(dòng)主要參數(shù)的確定165.1 概述165.2 中央傳動(dòng)主要參數(shù)的確定165.3 圓柱齒輪的結(jié)構(gòu)與計(jì)算175.4 齒輪強(qiáng)度計(jì)算18第六章 最終傳動(dòng)參數(shù)的確定206.1 概述206.2 最終傳動(dòng)主要參數(shù)的確定206.3 圓柱齒輪的結(jié)構(gòu)與計(jì)算216.4 齒輪強(qiáng)度計(jì)算22第七章 軸的校核247.1 概述247.2 軸的強(qiáng)度計(jì)算247.3 軸的剛度計(jì)算25第八章 軸承的校核288.1 概述288.2 軸承的校核28結(jié)論30參考文獻(xiàn)31致謝32 - 4 -