單(dan)向(xiang)閥(fa)又稱止(zhi)(zhi)回閥(fa)或(huo)逆止(zhi)(zhi)閥(fa)。用于液壓系統中防止(zhi)(zhi)油(you)流反向(xiang)流動。

      單(dan)向(xiang)閥(fa)(fa)(fa)有直(zhi)通(tong)式(shi)(shi)和直(zhi)角(jiao)(jiao)式(shi)(shi)兩種(zhong)(zhong)。直(zhi)通(tong)式(shi)(shi)單(dan)向(xiang)閥(fa)(fa)(fa)用(yong)螺(luo)紋連接安裝在(zai)管路(lu)上(shang)。直(zhi)角(jiao)(jiao)式(shi)(shi)單(dan)向(xiang)閥(fa)(fa)(fa)有螺(luo)紋連接、板(ban)式(shi)(shi)連接和法蘭連接三種(zhong)(zhong)形式(shi)(shi)。液(ye)(ye)(ye)控(kong)單(dan)向(xiang)閥(fa)(fa)(fa)也(ye)稱閉(bi)鎖閥(fa)(fa)(fa)或保壓(ya)(ya)(ya)閥(fa)(fa)(fa)，它與單(dan)向(xiang)閥(fa)(fa)(fa)相同，用(yong)以(yi)防止油(you)液(ye)(ye)(ye)反向(xiang)流動。但在(zai)液(ye)(ye)(ye)壓(ya)(ya)(ya)回路(lu)中需(xu)要油(you)流反向(xiang)流動時又可利(li)用(yong)控(kong)制(zhi)油(you)壓(ya)(ya)(ya)，打開單(dan)向(xiang)閥(fa)(fa)(fa)，使油(you)流在(zai)兩個方向(xiang)都可流動。液(ye)(ye)(ye)控(kong)單(dan)向(xiang)閥(fa)(fa)(fa)采(cai)用(yong)錐(zhui)形閥(fa)(fa)(fa)芯(xin)，因此(ci)(ci)密封性(xing)能好。在(zai)要求(qiu)封閉(bi)油(you)路(lu)時，可用(yong)此(ci)(ci)閥(fa)(fa)(fa)作(zuo)為油(you)路(lu)的(de)單(dan)向(xiang)鎖緊而起保壓(ya)(ya)(ya)作(zuo)用(yong)。液(ye)(ye)(ye)控(kong)單(dan)向(xiang)閥(fa)(fa)(fa)控(kong)制(zhi)油(you)的(de)泄(xie)(xie)漏(lou)方式(shi)(shi)有內泄(xie)(xie)式(shi)(shi)和外泄(xie)(xie)式(shi)(shi)二種(zhong)(zhong)。在(zai)油(you)流反向(xiang)出口(kou)無背壓(ya)(ya)(ya)的(de)油(you)路(lu)中可用(yong)內泄(xie)(xie)式(shi)(shi)；否(fou)則(ze)需(xu)用(yong)外泄(xie)(xie)式(shi)(shi)，以(yi)降低控(kong)制(zhi)油(you)壓(ya)(ya)(ya)力。