【正文】 桿臂再使連動(dòng)拉桿和橫拉桿做直線運(yùn)動(dòng)，改變車輪的方向，這是一種古典的機(jī)構(gòu)，現(xiàn)代轎車已大多不再使用，但又被最新方式的助力轉(zhuǎn)向裝置所應(yīng)用。歷史上曾出現(xiàn)過許多種形式的轉(zhuǎn)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。“十五”期間，我國機(jī)動(dòng)車行業(yè)包括汽車、農(nóng)用車、工程機(jī)械等將發(fā)展成為國民經(jīng)濟(jì)的支柱產(chǎn)業(yè)，汽車轉(zhuǎn)向器是符合國家重點(diǎn)扶持和優(yōu)惠政策的汽車關(guān)鍵零部件，是汽車重要的保安件之一。由于轉(zhuǎn)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(chǔ)油罐，它們分別相當(dāng)于電路系統(tǒng)中的電池、導(dǎo)線、開關(guān)、電機(jī)和地線的作用。轉(zhuǎn)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(zhì)，還需要有耐熱、耐候性。 現(xiàn)在有越來越多的汽車在轉(zhuǎn)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(zhuǎn)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(zhuǎn)向器。循環(huán)球式：這種轉(zhuǎn)向裝置是由齒輪機(jī)構(gòu)將來自轉(zhuǎn)向盤的旋轉(zhuǎn)力進(jìn)行減速，使轉(zhuǎn)向盤的旋轉(zhuǎn)運(yùn)動(dòng)變?yōu)闇u輪蝸桿的旋轉(zhuǎn)運(yùn)動(dòng)，滾珠螺桿和螺母夾著鋼球嚙合，因而滾珠螺桿的旋轉(zhuǎn)運(yùn)動(dòng)變?yōu)橹本€運(yùn)動(dòng)，螺母再與扇形齒輪嚙合，直線運(yùn)動(dòng)再次變?yōu)樾D(zhuǎn)運(yùn)動(dòng)，使連桿臂搖動(dòng)，連桿臂再使連動(dòng)拉桿和橫拉桿做直線運(yùn)動(dòng)，改變車輪的方向。其中轉(zhuǎn)向器是將操縱機(jī)構(gòu)的旋轉(zhuǎn)運(yùn)動(dòng)轉(zhuǎn)變?yōu)閭鲃?dòng)機(jī)構(gòu)的直線運(yùn)動(dòng)(嚴(yán)格講是近似直線運(yùn)動(dòng))的機(jī)構(gòu)，是轉(zhuǎn)向系的核心部件。該力矩通過轉(zhuǎn)向軸、轉(zhuǎn)向萬向節(jié)、和轉(zhuǎn)向傳動(dòng)軸輸入轉(zhuǎn)向器。機(jī)械轉(zhuǎn)向系的能量來源是人力，所有傳力件都是機(jī)械的，由轉(zhuǎn)向操縱機(jī)構(gòu)(方向盤)、轉(zhuǎn)向器、轉(zhuǎn)向傳動(dòng)機(jī)構(gòu)三大部分組成。動(dòng)力轉(zhuǎn)向器除具有以上三大部件外，其最主要的動(dòng)力來源是轉(zhuǎn)向助力裝置。轉(zhuǎn)向器的正效率η+影響轉(zhuǎn)向器正效率的因素有：轉(zhuǎn)向器的類型、結(jié)構(gòu)特點(diǎn)、結(jié)構(gòu)參數(shù)和制造質(zhì)量等。它能保證轉(zhuǎn)向后，轉(zhuǎn)向輪和轉(zhuǎn)向盤自動(dòng)回正。極限可逆式轉(zhuǎn)向器介于上述兩者之間。～10176。作用在轉(zhuǎn)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(zhuǎn)向盤上的力矩；Dsw為轉(zhuǎn)向盤直徑。4）轉(zhuǎn)向器角傳動(dòng)比及其變化規(guī)律式(2—7)表明：增大角傳動(dòng)比可以增加力傳動(dòng)比。隨轉(zhuǎn)向盤轉(zhuǎn)角變化，轉(zhuǎn)向器角傳動(dòng)比可以設(shè)計(jì)成減小、增大或保持不變的。直行位置的轉(zhuǎn)向器角傳動(dòng)比不宜低于15～16。2）轉(zhuǎn)向盤自由行程過大的原因造成轉(zhuǎn)向盤自由行程過大的原因，主要有如下幾個(gè)方面：(1)轉(zhuǎn)向器蝸桿與滾輪(或齒扇、指銷等)間隙過大；(2)轉(zhuǎn)向傳動(dòng)裝置松動(dòng)；(3)轉(zhuǎn)向傳動(dòng)裝置的球鉸鏈間隙過大(松動(dòng))；(4)前輪軸承或轉(zhuǎn)向節(jié)主銷與襯套配合不緊等。 為牢固支承轉(zhuǎn)向盤而設(shè)有轉(zhuǎn)向柱。（3） 汽車在任何行駛狀態(tài)下，轉(zhuǎn)向輪不得產(chǎn)生振動(dòng)，轉(zhuǎn)向盤沒有擺動(dòng)。正確設(shè)計(jì)轉(zhuǎn)向梯形機(jī)構(gòu)，可以使第一項(xiàng)得到保證。循環(huán)球式轉(zhuǎn)向器中一般有兩級(jí)傳動(dòng)副，第一級(jí)是由螺桿和螺母共同形成的螺旋槽內(nèi)裝有鋼球構(gòu)成的傳動(dòng)副，第二級(jí)是由螺母上齒條與搖臂軸上齒扇構(gòu)成的齒條齒扇傳動(dòng)副。轉(zhuǎn)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(zhuǎn)向器工作時(shí)，兩列鋼球只是在各自封閉的“流道”內(nèi)循環(huán)，而不致脫出。不過，對(duì)于前軸軸載質(zhì)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(diǎn)影響不大；而對(duì)于載重量較大的汽車，使用循環(huán)球式轉(zhuǎn)向器時(shí)，除可以在轉(zhuǎn)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(zhuǎn)向加力器。鋼球直徑應(yīng)符合國家標(biāo)準(zhǔn)，一般常在7～9mm范圍內(nèi)選用（表41）。（3）滾道截面 圖42 四段圓弧滾道截面當(dāng)螺桿和螺母各有兩條圓弧組成，形成四段圓弧滾道截面時(shí),見圖42，鋼球與滾道有四點(diǎn)接觸,傳動(dòng)時(shí)軸向間隙最小，可滿足轉(zhuǎn)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(zhuǎn)動(dòng)轉(zhuǎn)向輪要克服阻力,包括轉(zhuǎn)向輪繞主銷轉(zhuǎn)動(dòng)的阻力、車輪穩(wěn)定阻力、輪胎變形阻力和轉(zhuǎn)向系中的內(nèi)摩擦力等。圖61轉(zhuǎn)向搖臂軸結(jié)構(gòu)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(jì)算漸開線花鍵連接強(qiáng)度可按擠壓、彎曲和剪切來計(jì)算。 表61 循環(huán)球式轉(zhuǎn)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(fù)荷/N3500～38004700～73507000～90008300～1100010000～11000貨車和大客車前軸負(fù)荷/N3000～50004500～75005500～185007000～195009000～2400017000～3700023000～44000最大轉(zhuǎn)載質(zhì)量/Kg350100025002700350060008000首先根據(jù)汽車的前軸負(fù)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(shè)計(jì)計(jì)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(xué)好問的習(xí)慣，同時(shí)具有了一定的創(chuàng)新思維。：人工操作多，零部件磨損度在實(shí)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