一、四輪驅動是什么意思
四輪驅動,又稱全輪驅動,是指汽車前后輪都有動力的一種汽車驅動形式,一般用4X4或4WD來表示,如果你看見一輛車上標有上述字樣,那就表示該車輛擁有4輪驅動的功能,屬于四驅車。
四(si)輪(lun)驅動可按行駛路面狀態不(bu)同,將發(fa)動機輸出扭(niu)矩按不(bu)同比(bi)例分(fen)布在前后所(suo)有(you)(you)的輪(lun)子上(shang),以提高汽(qi)車的行駛能(neng)力(li),因此具有(you)(you)良好(hao)的通過性能(neng)。
現如今很多汽車(che)品(pin)牌都有四輪(lun)驅(qu)(qu)動(dong)(dong)汽車(che)車(che)型,其(qi)中又可分為全時(shi)驅(qu)(qu)動(dong)(dong)(Full-Time)、兼時(shi)驅(qu)(qu)動(dong)(dong)(Part-Time)、適時(shi)驅(qu)(qu)動(dong)(dong)(Real-Time)和兼時(shi)/適時(shi)混和驅(qu)(qu)動(dong)(dong)四種驅(qu)(qu)動(dong)(dong)模式。
二、四輪驅動系統的結構原理
四輪驅動(dong)(dong)汽車(che)的傳(chuan)動(dong)(dong)系(xi)統由離合器、變速器、傳(chuan)動(dong)(dong)軸(zhou)、分(fen)動(dong)(dong)箱、前萬向(xiang)傳(chuan)動(dong)(dong)裝置(zhi)、前驅動(dong)(dong)橋、后萬向(xiang)傳(chuan)動(dong)(dong)裝置(zhi)和后驅動(dong)(dong)橋組成。
工作時,分動(dong)(dong)器用來分配(pei)傳(chuan)遞到(dao)前(qian)軸(zhou)和后軸(zhou)的(de)轉矩(ju),?鏈條(tiao)傳(chuan)動(dong)(dong)裝置將轉矩(ju)傳(chuan)輸(shu)(shu)到(dao)前(qian)橋,差(cha)速器通(tong)(tong)過與(yu)輸(shu)(shu)入(ru)軸(zhou)同軸(zhou)布置的(de)輸(shu)(shu)出軸(zhou)來驅動(dong)(dong)后橋。前(qian)橋轉矩(ju)傳(chuan)輸(shu)(shu)到(dao)上(shang)鏈輪(lun)上(shang)。鏈輪(lun)位于上(shang)輸(shu)(shu)出軸(zhou)上(shang),可(ke)自(zi)由轉動(dong)(dong),它通(tong)(tong)過鏈條(tiao)驅動(dong)(dong)下(xia)鏈輪(lun)。下(xia)鏈輪(lun)與(yu)法蘭軸(zhou)固定在一起,形成前(qian)橋主減(jian)速器的(de)驅動(dong)(dong)力,驅動(dong)(dong)汽車。
三、四輪驅動系統的結構特點
四驅車的四(si)輪(lun)(lun)(lun)(lun)驅(qu)動(dong)裝置(zhi)是常嚙合(he)(he)式(shi),增加(jia)了粘(zhan)(zhan)性耦(ou)合(he)(he)器(qi),省去了手動(dong)分(fen)力(li)器(qi),自動(dong)將(jiang)(jiang)扭(niu)矩按需(xu)分(fen)配(pei)在(zai)前(qian)(qian)(qian)后(hou)輪(lun)(lun)(lun)(lun)子上。在(zai)正常路(lu)面上,四(si)輪(lun)(lun)(lun)(lun)驅(qu)動(dong)裝置(zhi)將(jiang)(jiang)引(yin)(yin)擎(qing)輸出扭(niu)矩的92%分(fen)配(pei)到前(qian)(qian)(qian)輪(lun)(lun)(lun)(lun),8%分(fen)配(pei)到后(hou)輪(lun)(lun)(lun)(lun);在(zai)滑溜的路(lu)面上,將(jiang)(jiang)至(zhi)少40%的引(yin)(yin)擎(qing)機(ji)輸出扭(niu)矩分(fen)配(pei)給(gei)后(hou)輪(lun)(lun)(lun)(lun);當前(qian)(qian)(qian)輪(lun)(lun)(lun)(lun)開始(shi)打(da)滑時,前(qian)(qian)(qian)、后(hou)輪(lun)(lun)(lun)(lun)的轉(zhuan)速差異會使(shi)耦(ou)合(he)(he)器(qi)中(zhong)的粘(zhan)(zhan)液立即變稠并鎖住耦(ou)合(he)(he)器(qi),從(cong)而使(shi)傳動(dong)軸只將(jiang)(jiang)扭(niu)矩傳遞(di)至(zhi)后(hou)輪(lun)(lun)(lun)(lun),待前(qian)(qian)(qian)、后(hou)輪(lun)(lun)(lun)(lun)地轉(zhuan)速差異消失就自動(dong)回復原有(you)驅(qu)動(dong)形式(shi)。