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)輪驅動可按行駛路面狀態不同(tong),將發動機輸(shu)出扭矩按不同(tong)比例(li)分(fen)布(bu)在前后所有的輪子(zi)上,以(yi)提(ti)高汽車的行駛能力,因此具(ju)有良好的通過性能。
現如今很多汽車(che)品牌都有(you)四輪驅(qu)動(dong)(dong)汽車(che)車(che)型,其中又可分為全時(shi)(shi)驅(qu)動(dong)(dong)(Full-Time)、兼時(shi)(shi)驅(qu)動(dong)(dong)(Part-Time)、適(shi)時(shi)(shi)驅(qu)動(dong)(dong)(Real-Time)和(he)兼時(shi)(shi)/適(shi)時(shi)(shi)混和(he)驅(qu)動(dong)(dong)四種驅(qu)動(dong)(dong)模式。
二、四輪驅動系統的結構原理
四(si)輪驅動(dong)(dong)汽車的傳動(dong)(dong)系統由離合器(qi)、變速(su)器(qi)、傳動(dong)(dong)軸、分動(dong)(dong)箱、前萬向傳動(dong)(dong)裝置、前驅動(dong)(dong)橋、后(hou)萬向傳動(dong)(dong)裝置和后(hou)驅動(dong)(dong)橋組成。
工作時,分動(dong)(dong)器用來(lai)分配傳遞到(dao)前軸(zhou)(zhou)和(he)后軸(zhou)(zhou)的轉(zhuan)矩,?鏈(lian)(lian)(lian)(lian)條傳動(dong)(dong)裝置(zhi)將(jiang)轉(zhuan)矩傳輸到(dao)前橋(qiao),差速(su)器通過與(yu)輸入(ru)軸(zhou)(zhou)同(tong)軸(zhou)(zhou)布置(zhi)的輸出(chu)軸(zhou)(zhou)來(lai)驅動(dong)(dong)后橋(qiao)。前橋(qiao)轉(zhuan)矩傳輸到(dao)上鏈(lian)(lian)(lian)(lian)輪上。鏈(lian)(lian)(lian)(lian)輪位(wei)于上輸出(chu)軸(zhou)(zhou)上,可自由(you)轉(zhuan)動(dong)(dong),它通過鏈(lian)(lian)(lian)(lian)條驅動(dong)(dong)下鏈(lian)(lian)(lian)(lian)輪。下鏈(lian)(lian)(lian)(lian)輪與(yu)法蘭軸(zhou)(zhou)固定在一起,形(xing)成前橋(qiao)主減(jian)速(su)器的驅動(dong)(dong)力(li),驅動(dong)(dong)汽(qi)車。
三、四輪驅動系統的結構特點
四驅車的(de)(de)四(si)輪(lun)(lun)驅動(dong)(dong)裝置是(shi)常(chang)嚙合式,增加了粘性耦(ou)合器(qi)(qi),省去(qu)了手動(dong)(dong)分(fen)力器(qi)(qi),自動(dong)(dong)將(jiang)扭矩按需分(fen)配(pei)在(zai)前后輪(lun)(lun)子上(shang)(shang)。在(zai)正常(chang)路面(mian)上(shang)(shang),四(si)輪(lun)(lun)驅動(dong)(dong)裝置將(jiang)引擎(qing)輸出扭矩的(de)(de)92%分(fen)配(pei)到前輪(lun)(lun),8%分(fen)配(pei)到后輪(lun)(lun);在(zai)滑溜的(de)(de)路面(mian)上(shang)(shang),將(jiang)至少40%的(de)(de)引擎(qing)機輸出扭矩分(fen)配(pei)給后輪(lun)(lun);當前輪(lun)(lun)開始打(da)滑時,前、后輪(lun)(lun)的(de)(de)轉(zhuan)速差異會(hui)使耦(ou)合器(qi)(qi)中(zhong)的(de)(de)粘液立即變稠(chou)并鎖住耦(ou)合器(qi)(qi),從而使傳(chuan)動(dong)(dong)軸只將(jiang)扭矩傳(chuan)遞至后輪(lun)(lun),待前、后輪(lun)(lun)地轉(zhuan)速差異消(xiao)失就自動(dong)(dong)回(hui)復(fu)原有驅動(dong)(dong)形(xing)式。