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。
四輪(lun)驅動可按行駛路面狀態不(bu)同,將發動機輸出扭矩按不(bu)同比例分布在(zai)前后所有的輪(lun)子上,以提高汽車的行駛能(neng)力(li),因此具有良好的通過性能(neng)。
現如今很多汽車(che)品牌都有四(si)輪(lun)驅(qu)(qu)動(dong)(dong)(dong)汽車(che)車(che)型,其中又可(ke)分(fen)為(wei)全時驅(qu)(qu)動(dong)(dong)(dong)(Full-Time)、兼(jian)時驅(qu)(qu)動(dong)(dong)(dong)(Part-Time)、適(shi)時驅(qu)(qu)動(dong)(dong)(dong)(Real-Time)和兼(jian)時/適(shi)時混和驅(qu)(qu)動(dong)(dong)(dong)四(si)種(zhong)驅(qu)(qu)動(dong)(dong)(dong)模(mo)式(shi)。
二、四輪驅動系統的結構原理
四輪(lun)驅(qu)(qu)動(dong)(dong)(dong)汽車的傳(chuan)動(dong)(dong)(dong)系統(tong)由(you)離合器、變速器、傳(chuan)動(dong)(dong)(dong)軸、分動(dong)(dong)(dong)箱、前萬向傳(chuan)動(dong)(dong)(dong)裝置、前驅(qu)(qu)動(dong)(dong)(dong)橋(qiao)、后(hou)萬向傳(chuan)動(dong)(dong)(dong)裝置和后(hou)驅(qu)(qu)動(dong)(dong)(dong)橋(qiao)組成。
工作時,分動(dong)器(qi)用來分配(pei)傳(chuan)遞到(dao)(dao)(dao)前軸(zhou)(zhou)和(he)后軸(zhou)(zhou)的(de)轉(zhuan)(zhuan)矩,?鏈(lian)條(tiao)傳(chuan)動(dong)裝置將轉(zhuan)(zhuan)矩傳(chuan)輸(shu)到(dao)(dao)(dao)前橋(qiao),差(cha)速器(qi)通(tong)過與(yu)輸(shu)入軸(zhou)(zhou)同軸(zhou)(zhou)布置的(de)輸(shu)出軸(zhou)(zhou)來驅(qu)動(dong)后橋(qiao)。前橋(qiao)轉(zhuan)(zhuan)矩傳(chuan)輸(shu)到(dao)(dao)(dao)上(shang)(shang)鏈(lian)輪上(shang)(shang)。鏈(lian)輪位于(yu)上(shang)(shang)輸(shu)出軸(zhou)(zhou)上(shang)(shang),可自由轉(zhuan)(zhuan)動(dong),它通(tong)過鏈(lian)條(tiao)驅(qu)動(dong)下鏈(lian)輪。下鏈(lian)輪與(yu)法蘭軸(zhou)(zhou)固(gu)定在(zai)一起,形成前橋(qiao)主減速器(qi)的(de)驅(qu)動(dong)力,驅(qu)動(dong)汽車。
三、四輪驅動系統的結構特點
四驅車的(de)(de)四輪(lun)驅(qu)(qu)動(dong)(dong)裝(zhuang)置是常嚙合(he)式(shi),增加了(le)粘(zhan)性耦合(he)器(qi)(qi),省去了(le)手動(dong)(dong)分(fen)力器(qi)(qi),自(zi)(zi)動(dong)(dong)將扭(niu)矩按需分(fen)配(pei)在前(qian)后(hou)輪(lun)子(zi)上。在正常路面上,四輪(lun)驅(qu)(qu)動(dong)(dong)裝(zhuang)置將引擎輸出扭(niu)矩的(de)(de)92%分(fen)配(pei)到(dao)前(qian)輪(lun),8%分(fen)配(pei)到(dao)后(hou)輪(lun);在滑溜的(de)(de)路面上,將至(zhi)少(shao)40%的(de)(de)引擎機輸出扭(niu)矩分(fen)配(pei)給后(hou)輪(lun);當(dang)前(qian)輪(lun)開始打滑時,前(qian)、后(hou)輪(lun)的(de)(de)轉速(su)差異(yi)會使耦合(he)器(qi)(qi)中的(de)(de)粘(zhan)液立(li)即變稠并鎖住耦合(he)器(qi)(qi),從(cong)而使傳動(dong)(dong)軸只將扭(niu)矩傳遞至(zhi)后(hou)輪(lun),待(dai)前(qian)、后(hou)輪(lun)地(di)轉速(su)差異(yi)消失(shi)就自(zi)(zi)動(dong)(dong)回復原有(you)驅(qu)(qu)動(dong)(dong)形式(shi)。