【正文】 Sons,Inc 1967附錄1：英文翻譯ADVANTAGES AND DISADVANTAGES OF HYDRAULIC CONTROLThere are many unique features of hydraulic control pared to other types of control. These are fundamental and account for the wide use of hydraulic control. Some of the advantages are the following: 1. Heat generated by internal losses is a basic limitation of any machine. Lubricants deteriorate, mechanical parts seize, and insulation breaks down as temperature increases. Hydraulic ponents are superior to others in this respect since the fluid carries away the heat generated to a convenient heat exchanger. This feature permits smaller and lighter ponents. Hydraulic pumps and motors are currently available with horsepower to weight ratios greater than 2hp/lb Small pact systems are attractive in mobile and airborne installations.2. The hydraulic fluid also acts as a lubricant and makes possible long ponent life. 3. There is no phenomenon in hydraulic ponents parable to the saturation and Iosses in magnetic of electrical torque developed by an electric motor is proportional to current and is limited by magnetic saturation. The torque developed by hydraulic actuators (., motors and pistons) is proportional to pressure difference and is limited only by safe stress levels. Therefore hydraulic actuators develop relatively large torques for paratively small devices. 4. Electrical motors are basically a simple lag device from applied voltage to speed. Hydraulic actuators are basically a quadratic resonance from flow to speed with a high natural frequency. Therefore hydraulic actuators have a higher speed of response with fast starts, stops, and speed reversals possible. Torque to inertia ratios are large with resulting high acceleration capability. On the whole, higher loop gains and bandwidths are possible with hydraulic actuators in servo loops. 5. Hydraulic actuators may be operated under continuous, intermittent, reversing, and stalled conditions without damage. With relief valve protection, hydraulic actuators may be used for dynamic breaking. Larger speed ranges are possible with hydraulic actuators. Both linear and rotary actuators are available and add to the flexibility of hydraulic power elements. 6. Hydraulic actuators have higher stiffness, that is, inverse of slope of speedtorque curves, pared to other drive devices since leakages are low. Hence there is little drop in speed as loads are applied. In closed loop systems this results in greater positional stiffness and less position error. 7. Open and closed loop control of hydraulic actuators is relatively simple using valves and pumps. 8. Other aspects pare less favorably with those of electromechanical control ponents but are not so serious that they deter wide use and acceptance of hydraulic control. The transmission of power is moderately easy with hydraulic lines. Energy storage is relatively simple with accumulators. Although hydraulic controls offer many distinct advantages, several disadvantages tend to limit their use. Major disadvantages are the following: 1. Hydraulic power is not so readily available as that of electrical power. This is not a serious threat to mobile and airborne applications but most certainly affects stationary applications. 2. Small allowable tolerances results in high costs of hydraulic ponents. 3. The hydraulic fluid imposes an upper temperature limit. Fire and explosion hazards exist if a hydraulic system is used near a soiirt of ignition. However, these situations have improved with the availability of high temperature and fire resistant fluids. Hydraulic systems are messy because it is diflicult to maintain a system free from leaks, and there is always the possibility of plete loss of fluid if a break in the system occurs. 4. It is impossible to maintain the fluid free of dirt and contamination. Contaminated oil can clog valves and actuators and, if the contaminant is abrasive, cause a permanent loss in performance and/or failure. Contaminated oil is the chief source of hydraulic control failures. Clean oil and reliability are synonymous terms in hydraulic control. 5. Basic design procedures are lacking and difficult to obtain because of the plexity of hydraulic control analysis. For example, the current flow through a resistor is described by a simple law—Ohm39。在圖書館查閱資時發(fā)現(xiàn)本科學習的知識相對于理論應用來說比較淺顯，課本中只是講述了液壓及其器件的基本原理，但在實踐中所要用到了公式并沒有涉及。PLC采用歐姆龍控制，芯片型號選CPM1A20CDTD，輸出形式是晶體管（NPN）這種形式適合工作頻繁的機械中，功能比較強大。但受烘干設備限制，油箱不能過大。適用于所有介質(zhì)，但受酸洗磷化槽限制，油箱不能太大。隔板高度為液面高度的2/3～3/4。設計油箱時應考慮如下幾點：1）油箱必須有足夠大的容積。過去認為，油箱還應起到分離和沉積油液中污物的作用，但現(xiàn)在的液壓系統(tǒng)污染控制理論，要求油箱不再是一個容納污垢的場合，油箱中的油液是達到一定清潔度等級的油液，以這樣清潔的油液提供給液壓泵和整個液壓系統(tǒng)的工作回路，因此對油箱的設計、制造、工作運行和維護都應按照以上這些功能的要求來實施。 6X 系列規(guī)格 6最大工作壓力 350 巴最大流量 80 l/min（直流）最大流量 60 l/min（交流）高功率閥用于底板安裝 E閥芯3個切換位 G24 24V直流電壓符合 DIN EN 175301803 規(guī)定的設備插頭 帶QR 型感應式位置開關，受監(jiān)控的開關位置 39。因直流電磁鐵的線圈本身就帶有電感性質(zhì)，而容量不足的濾波電容反而會造成電磁鐵輸入電壓的下降。電磁換向閥特點直流電磁換向閥的優(yōu)點是換向頻率高，換向特性好，工作可靠度高，對低電壓、短時超電壓、超載和機械卡住反應不敏感。機動換向閥原理 是利用機械的擋塊或凸輪壓住或離開行程滑閥的滾輪，以改變滑閥的位置，來控制油流的方向 一般為二位的或三位的，并有各種不同的通路數(shù)。 ，反向液流可以自由通過，若要求調(diào)節(jié)反向速度時，須加接入一個節(jié)流閥，通過分別調(diào)節(jié)，可以得到不同的往復速度。 降低 P1 通道中的壓力 1. 氟橡膠密封適用于2. 礦物油(HL,HLP) 按 DIN 51524，3. HETG （菜籽油）,4. HEPG （聚乙二醇）5. HEES （合成脂）6. 生物快速降解油液7. 按 VDMA 24568節(jié)流閥原理節(jié)流閥由節(jié)流口和調(diào)節(jié)節(jié)流口大小的裝置組成，閥心可作軸向移動，節(jié)流開口大小改變，從而調(diào)節(jié)流量。1．減壓閥是一種使閥門出口壓力（二次油路壓力）低于進口壓力（一次油路壓力）的壓力調(diào)節(jié)閥。液壓操縱單向閥是由上部錐形閥和下部活塞所組成，在正常油液的通路時，不接通控制油，與一般直角式單向閥一樣。溢流閥的調(diào)整壓力，應等于系統(tǒng)的工作壓力。加工精度要求高，成本高。每個疊加閥既有一般液壓元件的控制功能，又起到通道體的作用，每一種通徑系列的疊加閥其主油路通道和螺栓連接孔的位置都與所選用的相應通徑的換向閥相同，因此同一通徑的疊加閥都能按要求疊加起來，組成各種不同控制功能的系統(tǒng)。油缸快進時油管的流量可達。液壓傳動系統(tǒng)常用的管子有鋼管、橡膠軟管、尼龍管和塑料管等。下部結(jié)構(gòu)直接與立柱、工作臺等相連，結(jié)構(gòu)和受力狀態(tài)都很復雜。主要考慮到外形的美觀，對精度無要求。本次設計選用的是加熱預緊方式。因此，這種結(jié)構(gòu)僅在無精度要求的小型簡易液壓機中采用。對于截面的45鋼，≥375MPa，尺寸系數(shù)已考慮在內(nèi)，立柱表面為精車，對于正火的45鋼，因此[] 為30mm疲勞強度校核： == == 由機械設計手冊查出=K=1+（）==K==300[]為200MPa, 因此是安全的。當改變定子和轉(zhuǎn)子間的偏心距e的大小時，便可改變泵的排量，故單作用葉片泵都是變量泵。定子的內(nèi)表面（工作表面）是一個圓柱表面（筒形），轉(zhuǎn)子偏心地安放在定子中間，葉片裝在轉(zhuǎn)子上的