【正文】 nation of theory and practice, in theory under the premise of learning, with a better understanding of the actual content of what they have learned.Keywords: automobile steering system, working principle, failure, maintenance, programs, bining theory and practice緒論汽車(chē)轉(zhuǎn)向系統(tǒng)是用于改變或保持汽車(chē)行駛方向的專門(mén)機(jī)構(gòu)。汽車(chē)轉(zhuǎn)向系統(tǒng)的功能就是按照駕駛員的意愿控制汽車(chē)的行駛方向。就輪式汽車(chē)而言,實(shí)現(xiàn)汽車(chē)轉(zhuǎn)向的方法是, 駕駛員通過(guò)一套專設(shè)的機(jī)構(gòu),使汽車(chē)轉(zhuǎn)向橋(一般是前橋)上的車(chē)輪(轉(zhuǎn)向輪)相對(duì)于汽車(chē)縱橫線偏轉(zhuǎn)一定角度。動(dòng)力轉(zhuǎn)向系統(tǒng)：借助動(dòng)力來(lái)操縱的轉(zhuǎn)向系統(tǒng)。圖11向系統(tǒng)結(jié)構(gòu)上圖是一種機(jī)械式轉(zhuǎn)向系統(tǒng)。經(jīng)轉(zhuǎn)向器放大后的力矩和減速后的運(yùn)動(dòng)傳到轉(zhuǎn)向橫拉桿，再傳給固定于轉(zhuǎn)向節(jié)上的轉(zhuǎn)向節(jié)臂，使轉(zhuǎn)向節(jié)和它所支承的轉(zhuǎn)向輪偏轉(zhuǎn)，從而改變了汽車(chē)的行駛方向。 目前較常用的有齒輪齒條式、循環(huán)球曲柄指銷(xiāo)式、蝸桿曲柄指銷(xiāo)式、循環(huán)球齒條齒扇式、蝸桿滾輪式等。轉(zhuǎn)彎半徑越小，則汽車(chē)轉(zhuǎn)向所需場(chǎng)地就越小。直拉桿的典型結(jié)構(gòu)如圖15在轉(zhuǎn)向輪偏轉(zhuǎn)或因懸架彈性變形而相對(duì)于車(chē)架跳動(dòng)時(shí)，轉(zhuǎn)向直拉桿與轉(zhuǎn)向搖臂及轉(zhuǎn)向節(jié)臂的相對(duì)運(yùn)動(dòng)都是空間運(yùn)動(dòng)，為了不發(fā)生運(yùn)動(dòng)干涉，上述三者間的連接都采用球銷(xiāo)。圖16 　2 汽車(chē)轉(zhuǎn)向系統(tǒng)的故障診斷機(jī)械轉(zhuǎn)向系的常見(jiàn)故障部位主要有：轉(zhuǎn)向盤(pán)自由行程、轉(zhuǎn)向傳動(dòng)機(jī)構(gòu)連接處、轉(zhuǎn)向器等。具體原因主要有：①轉(zhuǎn)向輪輪胎氣壓不足，應(yīng)按規(guī)定充氣。⑤轉(zhuǎn)向器缺油或無(wú)油，應(yīng)按規(guī)定添加潤(rùn)滑油。⑨轉(zhuǎn)向節(jié)主銷(xiāo)與轉(zhuǎn)向節(jié)襯套配合過(guò)緊或缺油，或轉(zhuǎn)向節(jié)止推軸承缺油，應(yīng)予調(diào)整或添加潤(rùn)滑脂等。 故障現(xiàn)象汽車(chē)保持直線行駛位置靜止不動(dòng)時(shí)，轉(zhuǎn)向盤(pán)左右轉(zhuǎn)動(dòng)的游動(dòng)角度太大。②轉(zhuǎn)向盤(pán)與轉(zhuǎn)向軸連接部位松曠，應(yīng)予調(diào)整。⑥轉(zhuǎn)向節(jié)主銷(xiāo)與襯套磨損后松曠，應(yīng)予更換。尤其是高速時(shí)，轉(zhuǎn)向輪擺振嚴(yán)重，握轉(zhuǎn)向盤(pán)的手有麻木感，甚至在駕駛室可看到汽車(chē)車(chē)頭晃動(dòng)。③兩轉(zhuǎn)向輪的定位不正確，應(yīng)予調(diào)整或更換部件。⑦轉(zhuǎn)向器在車(chē)架上的連接松動(dòng)，應(yīng)予緊固。 故障診斷方法以桑塔納乘用車(chē)為例，根據(jù)轉(zhuǎn)向輪抖動(dòng)特征，按照?qǐng)D22械轉(zhuǎn)向系轉(zhuǎn)向輪抖動(dòng)常見(jiàn)故障原因的診斷流程找出故障部位。動(dòng)力轉(zhuǎn)向系的常見(jiàn)故障主要是轉(zhuǎn)向沉重和轉(zhuǎn)向噪聲。②油路堵塞或不暢，應(yīng)予檢修。⑥調(diào)節(jié)閥失效，使輸出壓力過(guò)低，應(yīng)予更換或調(diào)整。詳見(jiàn)圖23所示動(dòng)力轉(zhuǎn)向系轉(zhuǎn)向沉重助力部分常見(jiàn)故障原因的診斷流程。②轉(zhuǎn)向泵傳動(dòng)帶打滑，應(yīng)予調(diào)整或更換。 故障診斷方法轉(zhuǎn)向時(shí)發(fā)出“咔噠”聲，在已排除轉(zhuǎn)向泵葉片噪聲的情況下，則由轉(zhuǎn)向泵帶輪出現(xiàn)松動(dòng)引起。 轉(zhuǎn)向盤(pán)回位不良故障原因主要是：系統(tǒng)內(nèi)有空氣、壓力限制閥工作不良，控制閥彈簧失效等。）、轉(zhuǎn)向盤(pán)外緣最大轉(zhuǎn)向切向力（即轉(zhuǎn)向盤(pán)最大轉(zhuǎn)向力，N）、轉(zhuǎn)向輪最大轉(zhuǎn)向角（176。轉(zhuǎn)向輪定位應(yīng)該是行駛系的內(nèi)容，但由于該參數(shù)的改變，既可能造成行駛系故障（如輪胎異常磨損），也可能造成轉(zhuǎn)向系故障（如轉(zhuǎn)向沉重），因此轉(zhuǎn)向輪定位參數(shù)通常也作為轉(zhuǎn)向系的診斷參數(shù)。如果轉(zhuǎn)向太輕，又可能導(dǎo)致駕駛員路感太弱或汽車(chē)“發(fā)飄”，同樣不利于行車(chē)安全。 安裝將轉(zhuǎn)向參數(shù)測(cè)量?jī)x對(duì)準(zhǔn)被測(cè)轉(zhuǎn)向盤(pán)中心，調(diào)整好三只活動(dòng)卡爪長(zhǎng)度，與轉(zhuǎn)向盤(pán)牢固連接。轉(zhuǎn)向力的檢測(cè)可按轉(zhuǎn)向輕便性實(shí)驗(yàn)方法進(jìn)行，一般有原地轉(zhuǎn)向力實(shí)驗(yàn)、低速大轉(zhuǎn)角（“8”字行駛）轉(zhuǎn)向力實(shí)驗(yàn)、彎道轉(zhuǎn)向力實(shí)驗(yàn)等，可參照有關(guān)國(guó)家標(biāo)準(zhǔn)的規(guī)定進(jìn)行檢測(cè)。轉(zhuǎn)向盤(pán)自由轉(zhuǎn)動(dòng)量是一個(gè)綜合診斷參數(shù)，當(dāng)其超過(guò)規(guī)定的值時(shí)，說(shuō)明從轉(zhuǎn)向盤(pán)至轉(zhuǎn)向輪的傳動(dòng)鏈中有—處或幾處的配合出現(xiàn)松曠。刻度盤(pán)通過(guò)磁力座吸附在駕駛室儀表盤(pán)或轉(zhuǎn)向管柱上，指針則固定在轉(zhuǎn)向盤(pán)的周緣上；也可將指針通過(guò)磁力座固定在儀表板或轉(zhuǎn)向管柱上，而刻度盤(pán)固定在轉(zhuǎn)向盤(pán)周緣上。 檢查轉(zhuǎn)向傳動(dòng)軸萬(wàn)向節(jié)有無(wú)松動(dòng)、磨損，視情況予以更換。（2）檢查轉(zhuǎn)向器外殼是否破裂，視情況焊補(bǔ)或更換。15176。（6）潤(rùn)滑?，F(xiàn)以該車(chē)為例，闡述這類(lèi)轉(zhuǎn)向器的拆卸、檢修與裝配。③拆卸防塵套鎖簧和防塵罩管箍，拆下轉(zhuǎn)向器齒條防塵罩。拉出齒條時(shí)，應(yīng)使齒條朝向殼體側(cè)面再拔出，以防劃傷襯套；不允許旋轉(zhuǎn)齒條。用專用工具拆下軸上彈性擋圈，再用專用工具拆卸軸承。②檢查軸承是否松曠，若磨損嚴(yán)重應(yīng)更換新軸承。③裝配轉(zhuǎn)向小齒輪。注意不要?jiǎng)潅X條齒套。前后移動(dòng)轉(zhuǎn)向齒條約15次，使齒條處于穩(wěn)定狀態(tài)，然后繼續(xù)擰緊壓簧調(diào)整螺塞，如果沒(méi)有達(dá)到規(guī)定值，則應(yīng)重復(fù)以上操作。m。初步擰緊鎖緊螺母，在檢查調(diào)整好前輪前束后，最后擰緊鎖緊螺母。（3）緊固和潤(rùn)滑。④拆下轉(zhuǎn)向橫拉桿總成并分解。④球頭銷(xiāo)螺紋應(yīng)無(wú)損傷，否則應(yīng)更換；球頭銷(xiāo)彈簧不應(yīng)有彈力減弱或折斷現(xiàn)象，否則應(yīng)更換。將球頭銷(xiāo)的球頭涂以潤(rùn)滑脂，從轉(zhuǎn)向直拉桿側(cè)面的大孔中裝入。將轉(zhuǎn)向直拉桿的兩個(gè)球頭銷(xiāo)分別裝到轉(zhuǎn)向搖臂和轉(zhuǎn)向節(jié)上臂錐孔內(nèi)，按規(guī)定力矩?cái)Q緊球頭銷(xiāo)螺母，裝好開(kāi)口銷(xiāo)。分別將左、右橫拉桿接頭總成裝到橫拉桿的兩端，并擰緊左右橫拉桿接頭的4個(gè)螺栓。②檢查油液是否有起泡或乳化現(xiàn)象。如圖34，起動(dòng)發(fā)動(dòng)機(jī)并怠速運(yùn)轉(zhuǎn)，滿方向轉(zhuǎn)動(dòng)轉(zhuǎn)向盤(pán)數(shù)次，將壓力表閥門(mén)關(guān)閉（不超過(guò)5s），～ Map。 測(cè)量轉(zhuǎn)向盤(pán)上的轉(zhuǎn)向力超過(guò)40N應(yīng)予以檢查維修，同時(shí)，轉(zhuǎn)向盤(pán)自由行程應(yīng)在規(guī)定范圍內(nèi)。同時(shí)起動(dòng)發(fā)動(dòng)機(jī)怠速運(yùn)轉(zhuǎn)，左右轉(zhuǎn)動(dòng)轉(zhuǎn)向盤(pán)。 動(dòng)力轉(zhuǎn)向系的修理以寶來(lái)乘用車(chē)為例： 拆卸①拆下萬(wàn)向節(jié)，將萬(wàn)向節(jié)從轉(zhuǎn)向器中拉出。⑤密封好從轉(zhuǎn)向器上取下的軟管，并對(duì)轉(zhuǎn)向器上露出的螺紋進(jìn)行保護(hù)。②密封襯墊等經(jīng)過(guò)拆卸后應(yīng)更換新件。此種轉(zhuǎn)向器的常見(jiàn)損壞是漏油和齒輪齒條間隙過(guò)大。（3）轉(zhuǎn)向輪具有自動(dòng)回正能力。（7）橫、直拉桿不得拼焊。隨著未來(lái)汽車(chē)市場(chǎng)的快速發(fā)展和汽車(chē)電子價(jià)值含量的迅速提高，我國(guó)汽車(chē)電動(dòng)轉(zhuǎn)向系統(tǒng)將形成巨大經(jīng)濟(jì)規(guī)模效應(yīng)。t change the steering response characteristics are unable to control and transmission in the process of steering cannot with speed and lateral acceleration and other parameters of the changes, the pilot must pensate for car before in turn the steering response characteristics of certain operating pensation, such virtually increased the mental and physical burdens driver [2]. hydraulic steering system Hydraulic steering system (HPS) is the traditional mechanical steering system basis with a set of additional hydraulic booster, generally by oil pump, vshaped belt wheel, oil injection equipment, power devices and control valves etc. It with hydraulic oil pump is the power, through the movement to promote produced mechanical redirector work. Because the system through hydraulic works used to promote the traditional mechanical steering mechanism of steering movement so as to reduce the labor intensity, a driver in a certain extent, solve the traditional mechanical steering system caused because of transmission ratio fixed to light and sensitive the contradiction between. But, this kind of power steering system is driven by the steering wheel rotates the hydraulic system directly change torsion bar is the channel area to provide oiling the instrumentality of variable. Namely the discretion of size and speed boost have no relation with steering Angle, only concerned. Steering dish of greater perspective, turn the instrumentality of hydraulic systems provide is bigger also. Meanwhile, this system has the following weakness: (1) no matter car turn not to, as long as the engine and hydraulic motor drive ZhuLiBeng will work under the energy, the extra consumption engine. (2) the steering characteristics not adjusted, highspeed and same speed dynamical characteristics. In lowspeed steering need bigger boost, often for engine speed and low power poor effect, while in highspeed steering need smaller, will boost for engine speed high and power function big, bring about steering too sensitive, that the car manipulation stability bees poor. (3) the inherent hydraulic system of the hydraulic oil leakage problems and steering noise makes steering fort, meantime, dramatically reduced environmental pollution. Because of hydraulic steering system reliable work, mature technology, can provide the big steering and has been widely used. electrohydraulic power steering system Electrohydraulic power steering system at work steering characteristics can be changed. It basically has two kinds: electric hydraulic steering system (ECHPS) and electric hydraulic steering system (EHPS). Now automotive applications is the largest electric hydraulic booster turn from system. electronic control hydraulic power steering system Electric hydraulic steering system (ECHPS) in hydraulic steering system is based on the liquid flow rate increased control solenoid valves, torque sensor, the wheel speed sensors and steering control unit etc ponents. Ideally, car in spin to try to deft, request when in cars to different speed operation, which can realtime provide corresponding steering to overe the running speed to make drivers to resistance to manipulate the steering wheel can both lightweight, and have enough way feeling. In steering process, through the torque sensor, speed sensor etc sensing device will shift to rate, speed transfer to parameters such as steering control unit. After decoding, c