挖掘機(ji)的組(zu)成結構及其工(gong)作(zuo)原理

液(ye)壓(ya)(ya)(ya)挖掘機主要由發動(dong)機、液(ye)壓(ya)(ya)(ya)系(xi)統(tong)、工(gong)作裝置(zhi)、行走裝置(zhi)和(he)電氣控(kong)(kong)(kong)制(zhi)(zhi)等(deng)部分(fen)組(zu)成。液(ye)壓(ya)(ya)(ya)系(xi)統(tong)由液(ye)壓(ya)(ya)(ya)泵、控(kong)(kong)(kong)制(zhi)(zhi)閥、液(ye)壓(ya)(ya)(ya)缸、液(ye)壓(ya)(ya)(ya)馬(ma)達、管(guan)路、油(you)箱(xiang)等(deng)組(zu)成。電氣控(kong)(kong)(kong)制(zhi)(zhi)系(xi)統(tong)包(bao)括監控(kong)(kong)(kong)盤、發動(dong)機控(kong)(kong)(kong)制(zhi)(zhi)系(xi)統(tong)、泵控(kong)(kong)(kong)制(zhi)(zhi)系(xi)統(tong)、各類傳感器(qi)、電磁閥等(deng)。

液壓(ya)挖掘機一般由(you)工作裝(zhuang)置(zhi)、回轉裝(zhuang)置(zhi)和(he)行走裝(zhuang)置(zhi)三大部分(fen)組成。根(gen)據(ju)其構造和(he)用(yong)途可以區分(fen)為(wei)：履(lv)帶式(shi)、輪胎式(shi)、步履(lv)式(shi)、全液壓(ya)、半液壓(ya)、全回轉、非(fei)全回轉、通(tong)用(yong)型(xing)、專用(yong)型(xing)、鉸接式(shi)、伸縮臂(bei)式(shi)等多(duo)種(zhong)類型(xing)。

工(gong)(gong)作(zuo)(zuo)(zuo)裝置是直接完成挖掘任務的裝置。它由動(dong)臂、斗(dou)桿、鏟斗(dou)等三(san)部分鉸接而成。動(dong)臂起(qi)落(luo)、斗(dou)桿伸縮和(he)鏟斗(dou)轉(zhuan)動(dong)都用往復式雙作(zuo)(zuo)(zuo)用液(ye)壓缸控制。為了適應各種(zhong)(zhong)不同施(shi)工(gong)(gong)作(zuo)(zuo)(zuo)業的需(xu)要，液(ye)壓挖掘機(ji)可以配(pei)裝多種(zhong)(zhong)工(gong)(gong)作(zuo)(zuo)(zuo)裝置，如挖掘、起(qi)重、裝載、平整、夾鉗、推土(tu)、沖擊錘等多種(zhong)(zhong)作(zuo)(zuo)(zuo)業機(ji)具。

回轉(zhuan)與行走裝置是液壓(ya)挖掘(jue)機的機體，轉(zhuan)臺上(shang)部設有動(dong)(dong)力裝置和傳(chuan)動(dong)(dong)系統。發動(dong)(dong)機是液壓(ya)挖掘(jue)機的動(dong)(dong)力源，大多采用柴油要在方便的場(chang)地(di)， 也可(ke)改(gai)用電動(dong)(dong)機。

液壓傳動(dong)(dong)(dong)系(xi)(xi)統(tong)通過液壓泵將發動(dong)(dong)(dong)機的(de)動(dong)(dong)(dong)力傳遞給液壓馬達、液壓缸等執(zhi)行元件，推(tui)動(dong)(dong)(dong)工作(zuo)裝置動(dong)(dong)(dong)作(zuo)，從(cong)(cong)而(er)(er)完(wan)成各種(zhong)作(zuo)業。以工地使用(yong)較多的(de)PV-200型(xing)液壓挖掘機為例。該(gai)機采(cai)用(yong)改進型(xing)的(de)開式中心 負荷傳感系(xi)(xi)統(tong)（OLSS）。該(gai)系(xi)(xi)統(tong)用(yong)控(kong)制斜盤式變量(liang)柱塞泵斜盤角度（輸出流量(liang)）的(de)方法，減少(shao)了(le)發動(dong)(dong)(dong)機的(de)功率(lv)輸出，從(cong)(cong)而(er)(er)減少(shao)燃油消耗，是一(yi)種(zhong)節能型(xing)系(xi)(xi)統(tong)。

這(zhe)種液壓系統的特點是：定轉矩(ju)控制，能維持液壓泵驅動轉矩(ju)不變，載斷控制，可以減(jian)少作業時(shi)間(jian)的卸荷損失；油量控制，可減(jian)少空擋和微調(diao)控制時(shi)液壓泵的輸出流(liu)量，減(jian)少功率(lv)損失。