【正文】 桿臂再使連動拉桿和橫拉桿做直線運動，改變車輪的方向，這是一種古典的機構，現(xiàn)代轎車已大多不再使用，但又被最新方式的助力轉向裝置所應用。歷史上曾出現(xiàn)過許多種形式的轉向器，目前較常用的有齒輪齒條式、蝸桿曲柄指銷式、循環(huán)球齒條齒扇式、循環(huán)球曲柄指銷式、蝸桿滾輪式等?！笆濉逼陂g，我國機動車行業(yè)包括汽車、農用車、工程機械等將發(fā)展成為國民經(jīng)濟的支柱產業(yè)，汽車轉向器是符合國家重點扶持和優(yōu)惠政策的汽車關鍵零部件，是汽車重要的保安件之一。由于轉向助力裝置最常用的是一套液壓系統(tǒng)，因此也就離不開泵、油管、閥、活塞和儲油罐，它們分別相當于電路系統(tǒng)中的電池、導線、開關、電機和地線的作用。轉向盤外皮要求有某種程度的柔軟度，手感良好，能防止手心出汗打滑的材質，還需要有耐熱、耐候性。 現(xiàn)在有越來越多的汽車在轉向盤里安裝了安全氣囊，也使汽車的安全性大大提高了。歷史上曾出現(xiàn)過許多種形式的轉向器，目前較常用的有齒輪齒條式、蝸桿曲柄指銷式、循環(huán)球齒條齒扇式、循環(huán)球曲柄指銷式、蝸桿滾輪式等。所以，這是一種最簡單的轉向器。循環(huán)球式：這種轉向裝置是由齒輪機構將來自轉向盤的旋轉力進行減速，使轉向盤的旋轉運動變?yōu)闇u輪蝸桿的旋轉運動，滾珠螺桿和螺母夾著鋼球嚙合，因而滾珠螺桿的旋轉運動變?yōu)橹本€運動，螺母再與扇形齒輪嚙合，直線運動再次變?yōu)樾D運動，使連桿臂搖動，連桿臂再使連動拉桿和橫拉桿做直線運動，改變車輪的方向。其中轉向器是將操縱機構的旋轉運動轉變?yōu)閭鲃訖C構的直線運動(嚴格講是近似直線運動)的機構，是轉向系的核心部件。該力矩通過轉向軸、轉向萬向節(jié)、和轉向傳動軸輸入轉向器。機械轉向系的能量來源是人力，所有傳力件都是機械的，由轉向操縱機構(方向盤)、轉向器、轉向傳動機構三大部分組成。動力轉向器除具有以上三大部件外，其最主要的動力來源是轉向助力裝置。轉向器的正效率η+影響轉向器正效率的因素有：轉向器的類型、結構特點、結構參數(shù)和制造質量等。它能保證轉向后，轉向輪和轉向盤自動回正。極限可逆式轉向器介于上述兩者之間?！?0176。作用在轉向盤上的手力Fh可用下式表示Fh=2Mh/Dsw (2—4）式中，Mh為作用在轉向盤上的力矩；Dsw為轉向盤直徑。4）轉向器角傳動比及其變化規(guī)律式(2—7)表明：增大角傳動比可以增加力傳動比。隨轉向盤轉角變化，轉向器角傳動比可以設計成減小、增大或保持不變的。直行位置的轉向器角傳動比不宜低于15～16。2）轉向盤自由行程過大的原因造成轉向盤自由行程過大的原因，主要有如下幾個方面：(1)轉向器蝸桿與滾輪(或齒扇、指銷等)間隙過大；(2)轉向傳動裝置松動；(3)轉向傳動裝置的球鉸鏈間隙過大(松動)；(4)前輪軸承或轉向節(jié)主銷與襯套配合不緊等。 為牢固支承轉向盤而設有轉向柱。（3） 汽車在任何行駛狀態(tài)下，轉向輪不得產生振動，轉向盤沒有擺動。正確設計轉向梯形機構，可以使第一項得到保證。循環(huán)球式轉向器中一般有兩級傳動副，第一級是由螺桿和螺母共同形成的螺旋槽內裝有鋼球構成的傳動副，第二級是由螺母上齒條與搖臂軸上齒扇構成的齒條齒扇傳動副。轉向螺桿和螺母上都加工出斷面輪廓為兩段或三段不同心圓弧組成近似半圓的螺旋槽。因此，在轉向器工作時，兩列鋼球只是在各自封閉的“流道”內循環(huán)，而不致脫出。不過，對于前軸軸載質量不大而又經(jīng)常在平坦路面上行使的輕中型載貨汽車而言，這一缺點影響不大；而對于載重量較大的汽車，使用循環(huán)球式轉向器時，除可以在轉向器中增加吸振裝置以減少路面沖擊反力外，往往裝有液力轉向加力器。鋼球直徑應符合國家標準，一般常在7～9mm范圍內選用（表41）。（3）滾道截面 圖42 四段圓弧滾道截面當螺桿和螺母各有兩條圓弧組成，形成四段圓弧滾道截面時,見圖42，鋼球與滾道有四點接觸,傳動時軸向間隙最小，可滿足轉向盤自由行程小的要求。在螺距不變的條件下,鋼球直徑d越大,圖31中的尺寸b越小,要求b=Pd＞。30180。為轉動轉向輪要克服阻力,包括轉向輪繞主銷轉動的阻力、車輪穩(wěn)定阻力、輪胎變形阻力和轉向系中的內摩擦力等。圖61轉向搖臂軸結構簡圖本軸的漸開線花鍵可選擇45176。 外花鍵小徑Die= m() =()=；漸開線花鍵的校核計算漸開線花鍵連接強度可按擠壓、彎曲和剪切來計算。 表61 循環(huán)球式轉向器齒扇齒模數(shù)齒扇齒模數(shù)m/mm轎車排量/mL5001000～18001600～200020002000前軸負荷/N3500～38004700～73507000～90008300～1100010000～11000貨車和大客車前軸負荷/N3000～50004500～75005500～185007000～195009000～2400017000～3700023000～44000最大轉載質量/Kg350100025002700350060008000首先根據(jù)汽車的前軸負荷G1=14140N，查表,選取齒扇的模數(shù)m=5mm。齒頂圓直徑da=d+2ha=65+24=73mm。 螺桿軸設計計算及主要零件的校核螺桿軸用20CrMnTi鋼制造，～，表面淬火HRC 58～63。 齒扇齒數(shù)Z=5。 （6－4）圓整后取R2=4mm。 （6－6）螺桿受力 作用在螺桿上的軸向力F2（6－7）上式中d為變厚齒扇的分度圓直徑； 鋼球與螺桿之間的正壓力F3 F3= （6－8）上式中n為參與工作的鋼球數(shù)；為接觸角，=45186。養(yǎng)成了勤學好問的習慣，同時具有了一定的創(chuàng)新思維。：人工操作多，零部件磨損度在實際中尚不明確。39。 carburizing layer thickness, hardness。 C under the conditions of inspection, the shell and shell cap shaft oil seal joints as well as whether the spill, and water to observe whether there are leakages. (4) after a good tune steering assembly should check the technical requirements flexible and fortable when turning the steering wheel, there is no axial gap I turn the steering wheel of the total value of the number required to turn around a few cars in line with the original request. Steering gear shift, also known as machine, machine direction, which is steering the most important parts. Its role is to: increase the spread to turn steering wheel and transmission mechanism to change the direction of power transfer. Hydraulic Steering Hydraulic steering vehicles are widely used in marine hydraulic steering and rudder. Drivers can be used through its ability to manipulate smaller shift power to achieve greater control and performance of safe, reliable, flexible manipulation, light. The manipulation of steering is hydraulic, that is in the steering column and steering wheel there is no mechanical connection between the steering gear is between the fuel tank and steering hydraulic pipes or hoses link. When turning the steering wheel, steering wheel rotation in accordance with the relative proportion of transport fuel, the fuel tank directly into the corresponding control side, while the other side of the oil back to tank. BZZ steering is a switchtype fullhydraulic steering valve with the following characteristics: the elimination of mechanical linkage device, the host can reduce costs, provide a reliable, lightweight structures, manipulation of a flexible lightweight, safe, reliable, and can be very small continuous torque stepless control of rotation, provided to the control loop, as well as a wide range of host size choice, able to shift and a variety of pumps and hydraulic supply system. Steering by the structure can be divided into many types. History, there have been many forms of steering, there is currently more monly used rack and pinion, worm means crank pins, recycling the ball rack fan gear type, recycling the ball crank pins means, such as wormtype wheel. The second, fourth, respectively, is the first, the third form of the deformation, and the worm wheel is even more rare type. If the form in accordance with assistance, but also can be divided into mechanical (no help), and powerstyle (with help) two types of power steering which can be divided into pressure and motivation, hydraulicpower, electric powertype, electrohydraulic power types of blocks. 1) It is a rack and pinion of steering one of the most mon. The basic structure is a pair of mutually meshing rack and pinion. Pinion steering drive shaft rotates, rack linear motion would be done. In some cases, directly driven by the rack crossbar, you can make of steering wheel shift. So, this is one of the most simple steering. Its advantage is simple structure, lowcost, steering sensitivity, small size, can be directly crosslink. In widely used vehicle. It is a worm for the active parts, crank pin for the steering gear follower. Worm has a trapezoidal thread, referring to a fingershaped pin with tapered bearings in the crank bearings, the crank shaft and the shift into one arm. Shifted through steering wheel rotating worm, helical worm embedded in the cone