【正文】 hich the said one of the suspension linkages and the suspension lever arm are free to pivot about the axis relative to one another.[0015] In one preferred embodiment, the suspension dis connect apparatus prises a bore in the said one of the suspension linkages or in the suspension lever arm, the bore having a number of ball receiving tracks formed over a part of its length, a shaft slidably mounted to the other of the said one of the suspension linkages or the suspension lever arm,the shaft projecting into the bore and having a knuckle about which are mounted a plurality of balls, the shaft being movable from a first position in which the balls are engaged in the tracks to lock the said one of the suspension linkages and the suspension lever arm together for pivotal movement about the axis and a second position in which the balls arenot engaged in the tracks and the said one of the suspension linkages and the other end of the suspension lever arm are free to pivot about the axis relative to one another.[0016] Preferably, the suspension disconnect apparatus prises an actuator, which may be an hydraulic actuator,to move the shaft between the first and second positions.[0017] In an alternative embodiment, the said one of the suspension linkages and the suspension lever arm have adjacent drive portions and the suspension disconnect apparatus further prises a sleeve having drive means for cooperation With corresponding drive means on the driveportions, the sleeve being movable from a first position in which it is in driving cooperation with both of the drive portions to lock the said one of the suspension linkages and the suspension lever arm together for pivotal movement about the axis, and a second position in which it is in driving cooperation with only one of the drive portions such that thelinkage and the arm are free to pivot about the axis relative to one another.[0018] Preferably, the sleeve is internally splined for engagement with corresponding splines formed on the drive portions. Alternatively, a bore of the sleeve may have a noncircular cross section for driving engagement with correspondingly shaped profiles on the drive portions.[0019] Preferably, the suspension disconnect apparatus prises an actuator, which may be an hydraulic actuator, to move the sleeve between the first and second positions.[0020] In a yet further preferred embodiment, the said one of the suspension linkages and the suspension lever arm have corresponding drive teeth and the suspension lever arm is movable between a first position in which the drive teeth are engaged so as to lock the said one of the suspension linkages and the suspension lever arm together for pivotalmovement about the axis, and a second position in which the drive teeth are disengaged such that the said one of the suspension linkages and the suspension lever arm are free to pivot about the axis relative to one another.[0021] Preferably, the suspension disconnect apparatus prises an actuator, Which may be a hydraulic actuator, to move the suspension lever arm between the first and second positions.[0022] Preferably, the vehicle further prises a retraction disconnect apparatus for operatively connecting the retraction means to, or operatively disconnecting the retraction means from, one of the suspension linkages.[0023] Preferably, the retraction means prises a retraction actuator operatively connected to one end of a retraction lever arm, the other end of the retraction lever arm being connectable to said one of the suspension linkages through the retraction disconnect apparatus.[0024] Preferably, the said one of the suspension linkages and the retraction lever arm are mounted to the vehicle body for pivotal movement relative to the vehicle 。[29]Frank . Automotive Electronic Fundamentals,Glencoe Division Macmillan/McGrawHill. Columbus,. 1991。[25]吳亞良主編，《現(xiàn)代轎車車身設(shè)計》，上海，上?？茖W(xué)技術(shù)出版社，1999。[21]陳家瑞主編，《汽車構(gòu)造》北京，吉林工業(yè)大學(xué)，2002。[17]襲建軍、欒英艷主編，《AutoCAD2000基礎(chǔ)教程》，哈爾濱，哈爾濱工業(yè)大學(xué)出版社，2001。[13]龔桂義，《機械設(shè)計課程設(shè)計圖冊》，第三版，哈爾濱工業(yè)大學(xué)出版社，1989。[9] 成大先，《機械設(shè)計手冊》，第四版，第二卷，化學(xué)工業(yè)出版社，2002。[5] 劉衡章，《使用當(dāng)代汽車自動傳動技術(shù)》，人民郵電出版社，2001。37參考文獻[1] 楊楚泉，《水陸兩棲車輛原理與設(shè)計》，國防工業(yè)出版社，2003。（5） 水陸兩棲快艇的密封：參考一般船舶螺旋槳的密封手段，大致提出了我的設(shè)計中需要密封部分的密封方式。（3） 分動器的設(shè)計：我設(shè)計的水陸兩棲快艇以汽車為模板，在此基礎(chǔ)上進行改進，達到實現(xiàn)水陸兩用的功能，其中主要的設(shè)計方面就是分動器。在畢業(yè)設(shè)計的過程中，不僅鍛煉了我發(fā)現(xiàn)問題、分析問題、解決問題的能力，還培養(yǎng)了自己的邏輯感，能有條不紊的進行其中各方面的工作，知道了如何科學(xué)的利用時間進行設(shè)計任務(wù)，知道了設(shè)計的標(biāo)準(zhǔn)和其中需要注意的方面。 另外，充壓并可調(diào)壓的中間腔將油和海水隔開，即使在事故情況下海水也不能進入船內(nèi)，油也不能溢出船外。 尾軸管密封有各種不同的技術(shù)解決辦法。兩棲快艇需要密封的主要部分有：后輪輪軸與車體之間的密封，前后輪懸架和車體間的密封，螺旋槳和車體間的密封。圖64 方向控制系統(tǒng)圖中23為擺臂，24為裝箱節(jié)臂，25為轉(zhuǎn)向橫拉桿，26為擺桿，27為拉桿，28為方向盤。 簡略成型我在本文中只做比較簡單的設(shè)計，上下三角懸架使用相同的尺寸，保證在收起放下后始終使輪胎支撐架保持垂直，這樣就能保證輪胎始終能保持垂直狀態(tài)。 參考資料前后輪都采用雙橫臂式螺旋彈簧獨立懸架系統(tǒng)。圖示位置分動器處于空檔位置。在錐環(huán)與錐盤接觸瞬間，鎖銷與接合套齒端斜面相接觸。m —鍵與輪轂鍵槽的接觸高度，平鍵，此處為鍵的高度；單位：mm —鍵的工作長度，A型平鍵，為鍵的公稱長度，為鍵的寬度；單位：mm —軸的直徑，單位：mm —最小的材料的許用擠壓應(yīng)力，單位：MPa所以有， （524）所以強度足夠。mm —軸的抗彎截面系數(shù)，單位：mm —扭轉(zhuǎn)切應(yīng)力為靜應(yīng)力時，所以 （522） MPa查文獻得：=213 MPa故，即安全。 繪制轉(zhuǎn)矩圖如圖54（h）。（2） 計算支承反力在水平面上 == =1376 N （516） =1376=501N （517）垂直面內(nèi)的支反力： == N == N水平面內(nèi)的支反力： = = N（3） 計算彎矩 垂直面內(nèi)： （518） mm N 軸徑的初步計算 軸承的選擇根據(jù)初選的軸的直徑，再根據(jù)階梯軸的特性，安排各段軸的直徑大小，因為有比較小的軸向力，因此選取角接觸軸軸承，輸入軸和螺旋槳輸出軸的軸承選取為7009C，后輪輸出軸兩端選取為7012C。因為一對齒輪的齒數(shù)和以互為質(zhì)數(shù)為好，以防止齒輪磨損集中于某幾個齒上，而且為了保證最低車速不低于50km/h，故取，反算傳動比得重合度軸面重合度：查表得重合度系數(shù)；（8）查表得螺旋角系數(shù)；（9）許用接觸應(yīng)力由式44計算： （54）查表得接觸疲勞極限應(yīng)力為：。平均硬度為在之間，選用8級精度。通過撥叉撥動5向左移動可接通驅(qū)動橋，撥動2向左移動可接通螺旋槳，同時使5向左移動則同時接通后橋和螺旋槳。圖51分動器原理圖在圖51中，軸1為輸入軸，與變速器輸出軸相連。最后進行了防沉性的計算。反射水波的能量正是車輛阻力增加值的一部分。 所以螺旋槳可以得到的最大功率為 。 選用的發(fā)動機最大功率為108kw。從能量的觀點來看，產(chǎn)生波浪必然消耗能量，而且只能