【正文】 液控主控制換向閥3定差溢流閥3安全閥34和梭閥35組成流量放大閥。動臂液壓缸53補油和過載保護補油：動臂液壓缸53活塞腔或活塞桿腔吸空時，通過液控單向閥51補油。b、低壓保護調(diào)壓閥22控制補油壓力。，斜軸式軸向柱塞變量泵5高壓油口→前輪內(nèi)曲線徑向柱塞馬達9（后輪內(nèi)曲線徑向柱塞馬達10）→斜軸式軸向柱塞變量泵5低壓油口。工作裝置為反轉(zhuǎn)連桿式。工作裝置（1）、工作壓力10—14；（2）、轉(zhuǎn)斗缸最大推力22；鏟斗卸載時間3—6；轉(zhuǎn)斗時間2—5；轉(zhuǎn)斗缸行程520；（3）、動臂缸最大推力20；動臂提升時間2—5；動臂下降時間3—6；動臂缸行程560。先導泵3→液動閥25上位→變量液壓缸24上腔→變量液壓缸24活塞桿縮回→杠桿機構→斜軸式軸向柱塞變量泵5的缸體擺角↓或↑→斜軸式軸向柱塞變量泵5的流量↓或↑。過載保護：轉(zhuǎn)斗液壓缸52活塞腔或活塞桿腔過載時，通過過載閥49開啟溢流。先導泵3→全液壓轉(zhuǎn)向器31下腔→計量馬達進口→計量馬達出口→液動主控制閥32左端（液壓主控制閥左位工作）→液動主控制閥32中的先導閥口→液動主控制閥32的右端→全液壓轉(zhuǎn)向器31下位→過濾器55→油箱61。 則 ==39600注：由于系統(tǒng)是四輪驅(qū)動，采用的2個泵，所以計算時要除以2?？v向彎曲極限力計算 液壓缸受縱向力以后，產(chǎn)生軸線彎曲，當縱向力達到極限力以后，缸產(chǎn)生縱向彎曲，出現(xiàn)不穩(wěn)定現(xiàn)象。即 ==取 =16閥芯的直徑：按經(jīng)驗取 ～） =（～）16 =8～取 =13閥芯活塞直徑：按經(jīng)驗取 =（～） =（～）13 =～取 =30對閥的靜態(tài)特性影響很大，按上式選取時，對額定流量小的閥選較大的值。查表得其許用切應力===855。系統(tǒng)設有過載保護和吸空補油回路，很好的保護了系統(tǒng)中的各元件。s reform and opening up policy guidelines, with the development of the machinery industry, based mainframe pieces behind the conflicts have bee increasingly prominent and attracted the attention of the relevant departments. To this end, the Ministry of the original one in 1982, formed the basis of mon pieces of Industry, will be scattered in the original machine tools, agricultural machinery, mechanical engineering industries centralized hydraulic, pneumatic and seals specialized factories, placing them under mon management infrastructure pieces Bureau, so that the industry in the planning, investment, technology and scientific research and development in areas such as infrastructure pieces Bureau of guidance and support. Since then entered a phase of rapid development, has introduced more than 60 items of advanced technology from abroad, including more than 40 items of hydraulic, pneumatic 7. After digestion and absorption and transformation, now have mass production, and industryleading products. In recent years, the industry increased the technological transformation efforts, in 1991, Local enterprises and the selffinancing total input of about 20 billion yuan, of which more than billion yuan Hydraulic. Through technological transformation and technology research, and a number of major enterprises to further improve the level of technology, technique and equipment to be greatly improved. In order to form a higher starting point, specialization, and run production has laid a good foundation. In recent years, many countries in the development of mon ownership guidelines, under different ownership SMEs rapid rise showing great vitality. With the further opening up, threefunded enterprises rapid development of industry standards for improving and expanding exports play an important role. Today, China has and the United States, Japan, Germany and other countries famous manufacturers joint ventures or whollyowned by foreign manufacturers to establish a piston pump / motor, planetary reduction gears, steering gear, hydraulic control valve, hydraulic system, hydrostatic transmission, hydraulic Casting. pneumatic control valve, cylinder, gas processing triple pieces, mechanical seals, rubber and seal products more than 50 production enterprises, attracting foreign investment over 200 million . dollars. the current situation Profiles After 40 years of efforts, China hydraulic, pneumatic and sealing industry has formed a relatively plete categories. a certain level of technical capacity and the industrial system. According to the 1995 Third National Industrial Census statistics, hydraulic, Pneumatic seals and industrial 370,000 annual sales ine of 100 million yuan in stateowned, villagerun, private and cooperative enterprises, individual, three capital enterprises with a total of more than 1,300, of which about 700 hydraulic, Pneumatic seals and the approximately 300 thousand. By 1996 with the international trade statistics, the total output value of China39。 and the host of urgent hightech highparameter, high valueadded highend products, and they do not satisfy the market needs, only dependent on imports. China joins the WTO, its impact may be even greater. Therefore, the 15 during the growth of the output value of industry, must not depend on volume growth and the industry should address the structural problems of their own, increase the intensity of the adjustment of the industrial structure and product mix, is, we should rely on the improvement of quality, and promote technical upgrading of products to meet market demand and stimulating, seek greater development.2 The application of hydraulic power sliding stage Power sliding Taiwan introducedThis paper deals with the investigation for slide unit39。ity in modular machine tool fay means of the method of power bond graph and state space analysis. The dynamic mathematical model of selfadjusting back pressure speed control system used to drive slide unit is established. Main reasons and affect172。s 6。轉(zhuǎn)向機構液壓系統(tǒng)采用方向盤轉(zhuǎn)向，運用人機學，使駕駛室的布置更為合理，便于操縱。彈簧鋼絲直徑由彈簧直徑和彈簧中經(jīng)計算其旋繞比 ==查得其曲度系數(shù)=。如果節(jié)流孔太大或太短，則節(jié)流作用不夠，將使閥的啟閉特性變差，而且工作中會出現(xiàn)較大的壓力振擺；反之，如果節(jié)流孔太小或太長，則閥的動作會不穩(wěn)定，壓力超調(diào)量也會加大。 細長＞時： （55） 細長≤時: （56）式中： ——活塞桿的計算長度（），查表得：取兩端鉸接，=930； ——活塞桿橫截面積回轉(zhuǎn)半徑（），===20； ——活塞桿橫截面積轉(zhuǎn)動慣量（），===2009600； ——活塞桿橫截面積（），===5024； ——柔性系數(shù)，對鋼取=85； ——端蓋安裝形式系數(shù)，查表得：=1； ——材料彈性模數(shù)（），對鋼=206； ——材料強度實驗值（），對鋼≈490； ——系數(shù)，對鋼取。則： ===液壓泵的理論流量：===液壓泵的功率：=== 液壓馬達的參數(shù)液壓馬達的排量： （24）式中： ——液壓馬達的最大轉(zhuǎn)速（），===；——液壓馬達的機械效率，取=；——液壓馬達的進出口壓力差（），=251=24=24；——最大牽引力（），采用的是4馬達驅(qū)動，則：==19800。回油路：轉(zhuǎn)向液壓缸54A活塞桿腔和B活塞腔油→液動主控制閥32左腔→過濾器55→油箱61。（2）、主油路進油路：工作泵2→節(jié)流閥44→單向閥43→動臂舉升多路液動換向閥42左腔→動臂液壓缸53活塞腔動臂液壓缸53舉升。 高速檔（變速閥15圖示位）c、通過變速閥15，可得兩檔車速 低速檔（變速閥15左