當液道關閉后流速不完全沖擊(t < T)時，用 δp = a? ？是嗎？對你？T/T (千克力/厘米2) ，因此，為了減少或避免快速關閉通道引起的液壓沖擊，采取以下措施: 1)延長通道關閉時間，如先導閥減慢換向閥，換向速度。合肥挖掘機修理廠挖掘的物料主要是土壤、煤、泥沙以及經過預松后的土壤和巖石。從近幾年工程機械的發展來看，挖掘機的發展相對較快，挖掘機已經成為工程建設中最主要的工程機械之一。安徽挖掘機維修對挖掘機進行定期的車輛清潔，部件檢查潤滑以及對受損零件的更換和維修等內容，主要的目的就是為了有效地保證挖掘機的工作效果和良好的技術狀態，避免出現由于零部件損耗而導致的故障發生，為人們的安全提供良好的保障。挖掘機修理廠最(zui)初挖掘(jue)機(ji)是手動(dong)的(de)(de)，從發(fa)(fa)明到(dao)現(xian)在已經有一百(bai)三十多年了(le)，期間(jian)經歷了(le)由蒸汽驅(qu)動(dong)斗回轉(zhuan)挖掘(jue)機(ji)到(dao)電(dian)力(li)驅(qu)動(dong)和內燃機(ji)驅(qu)動(dong)回轉(zhuan)挖掘(jue)機(ji)、應用機(ji)電(dian)液(ye)一體(ti)化技術(shu)的(de)(de)全自動(dong)液(ye)壓(ya)挖掘(jue)機(ji)的(de)(de)逐步發(fa)(fa)展過(guo)程。2)在關閉通道(dao)前(qian)降低流速(su)，如打開滑閥末端的(de)(de)緩沖(chong)槽。3)縮(suo)短(duan)沖(chong)擊波的(de)(de)傳(chuan)播和反射時間(jian)，如縮(suo)短(duan)管(guan)道(dao)之間(jian)的(de)(de)距離(li)，或在靠近管(guan)道(dao)封閉部分的(de)(de)位置(zhi)設置(zhi)蓄能器(qi)。4)減小沖(chong)擊波的(de)(de)速(su)度，如采用較(jiao)大的(de)(de)管(guan)徑(jing)，采用較(jiao)大的(de)(de)彈(dan)性系數的(de)(de)管(guan)材，如橡膠(jiao)管(guan)。

運(yun)動(dong)(dong)部件(jian)制動(dong)(dong)時(shi)(shi)產(chan)生(sheng)(sheng)的 液(ye)壓(ya)沖(chong)擊(ji)Δp＝ΣmΔv/FΔt（公(gong)斤力／厘(li)米(mi)2）式(shi)中(zhong)：m—被制動(dong)(dong)運(yun)動(dong)(dong)部件(jian)的 質量(liang)（公(gong)斤力?秒2／厘(li)米(mi)）F—液(ye)壓(ya)缸有(you)效工作面積（厘(li)米(mi)2）由上式(shi)可知，為減(jian)(jian)小運(yun)動(dong)(dong)部件(jian)制動(dong)(dong)時(shi)(shi)產(chan)生(sheng)(sheng)的 液(ye)壓(ya)沖(chong)擊(ji)，應延長制動(dong)(dong)時(shi)(shi)所需的 時(shi)(shi)間(jian)，或縮(suo)小運(yun)動(dong)(dong)部件(jian)速(su)(su)(su)度(du)的 減(jian)(jian)小值。如在(zai)液(ye)壓(ya)缸行程終點采用減(jian)(jian)速(su)(su)(su)、節(jie)流等緩沖(chong)裝置等。二、空穴現象液(ye)壓(ya)泵(beng)吸(xi)油入口壓(ya)力可按(an)下(xia)式(shi)計算p泵(beng)＝pa-(hλγ+v2γ/2g+?v2γ/2g +p慣(guan))式(shi)中(zhong)：p泵(beng)—液(ye)壓(ya)泵(beng)吸(xi)油入口壓(ya)力吸(xi)油損耗pa—大氣壓(ya)力p慣(guan)—由于液(ye)體在(zai)吸(xi)入管和泵(beng)室中(zhong)加速(su)(su)(su)運(yun)動(dong)(dong)所產(chan)生(sheng)(sheng)的 壓(ya)力。

—吸(xi)油(you)高(gao)度v—吸(xi)油(you)管(guan)中油(you)液流速Σξ—吸(xi)油(you)部分(fen)(fen)工作阻力相(xiang)關系(xi)數(shu)γ—重(zhong)度三、溫(wen)(wen)(wen)(wen)(wen)升一(yi)般采用(yong)液壓(ya)控制(zhi)系(xi)統(tong)(tong)的(de) 油(you)溫(wen)(wen)(wen)(wen)(wen)不(bu)(bu)(bu)(bu)應(ying)影響超(chao)過(guo)(guo)70℃，作熱計算時(shi)一(yi)般高(gao)油(you)溫(wen)(wen)(wen)(wen)(wen)為60℃。高(gao)壓(ya)管(guan)理系(xi)統(tong)(tong)實現(xian)油(you)溫(wen)(wen)(wen)(wen)(wen)不(bu)(bu)(bu)(bu)應(ying)存在超(chao)過(guo)(guo)50℃，機(ji)床進行系(xi)統(tong)(tong)的(de) 油(you)溫(wen)(wen)(wen)(wen)(wen)達到(dao)規定不(bu)(bu)(bu)(bu)超(chao)過(guo)(guo)室溫(wen)(wen)(wen)(wen)(wen)25℃，精(jing)密加工機(ji)床通過(guo)(guo)液壓(ya)技術系(xi)統(tong)(tong)以及油(you)溫(wen)(wen)(wen)(wen)(wen)不(bu)(bu)(bu)(bu)超(chao)過(guo)(guo)室溫(wen)(wen)(wen)(wen)(wen)的(de) 10℃~15℃。各油(you)溫(wen)(wen)(wen)(wen)(wen)范(fan)圍的(de) 性(xing)質，可(ke)參見(jian)下表。溫(wen)(wen)(wen)(wen)(wen)度分(fen)(fen)布范(fan)圍（℃）溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)性(xing)質可(ke)以說明80~100危險環境溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)不(bu)(bu)(bu)(bu)許(xu)我(wo)們使用(yong)65~80臨界表面溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)油(you)的(de) 壽命周期(qi)縮(suo)短，必(bi)須裝冷卻器(qi)，溫(wen)(wen)(wen)(wen)(wen)度每上升8℃，油(you)的(de) 壽命不(bu)(bu)(bu)(bu)斷縮(suo)短企業一(yi)半(ban)55~65注意不(bu)(bu)(bu)(bu)同溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)47~55全溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)油(you)溫(wen)(wen)(wen)(wen)(wen)適當30~47理想目標(biao)溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)20~30常(chang)溫(wen)(wen)(wen)(wen)(wen)反應(ying)溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)啟(qi)動(dong)一(yi)個(ge)危險，效率低(di)0~20低(di)溫(wen)(wen)(wen)(wen)(wen)處(chu)理溫(wen)(wen)(wen)(wen)(wen)度區(qu)(qu)啟(qi)動(dong)主要危險