液壓與氣壓傳動外文翻譯(完整版)

　　

【正文】 ng parts of pneumatic ponents. Free air from the atmosphere contains varying amounts of moisure. This moisure can be harmful in that it can wash away lubricants and thus cause excessive wear and corrosion. Hence ,in some applications ,air driers are needed to remove this undesirable moisture. Since pneumatics systems exhaust directly into the atmosphere, they are capable of generating excessive noise. Therefore, mufflers are mounted on exhaust ports of air valves and actuators to reduce noise and prevent operating personnel from injury resulting not only from exposure to noise but also from highspeed airborne particles. There are several reasons for considering the use of pneumatic systems instead of hydraulic systems. Liquids exhibit greater inertia than do gases. Therefore, in hydraulic systems the weight of oil is a potential problem when accelerating and decelerating actuators and when suddenly opening and closing valves. Due to Newton’s law of motion(force equals mass multiplied by acceleration), the force required to accelerate oil is many times greater than that required to accelerate an equal volume of air. Liquids also exhibit greater viscosity than do gases. This results in larger frictional pressure and power losses. Also ,since hydraulic systems use a fluid foreign to the atmosphere, they require special reservoirs and noleak system designs. Pneumatic system use air which is exhausted directly back into the surrounding environment. Generally speaking, pneumatic systems are less expensive than hydraulic systems. However, because of the pressibility of air, it is impossible to obtain precise controlled actuator velocities with pneumatic systems. Also, precise positioning control is not obtainable. While pneumatics pressures are quite low due to pressor design limitations(less than 250 psi), hydraulic pressures can be as high as 10000 psi. Thus, hydraulics can be highpower systems, whereas pneumatics are confined to lowpower applications. Industrial applications of pneumatics systems are growing at a rapid pace. Typical examples include stamping, drilling, hoist, punching, clamping, assembling, riveting, materials handling, and logic controlling operations. 翻譯： 流體和液壓系統 水力的歷史由來已久，始于人類為利用它周圍的能源而做出的努力。這意味著流體在靜止時，在其內部沒有剪切力（作用表面切向方向的受力）存在。因此，泵使液體在系統中流動，泵的進口連接液流源，經常叫油槽或油箱。油流的動能相對比較低，因此有時采用靜壓傳動。另外，它們能像改變速度一樣容易來改變驅動的方向。然而液壓系統與電氣相比，傳遞動力的距離較短。 液壓系統在工業中應用廣泛，例如沖壓、鋼類工件的磨削及一般加工業、農業、礦業、航天技術、深海勘探、運輸、海洋技術，近海天然氣和石油勘探等行業，簡而言之，在日常生活中很少有人不從液壓技術得到某些益處。 4. 簡單、安全、經濟總的來說，液壓系統比機械或電氣系統使用更少的運動部件，因此，它們運行與維護簡單。 氣壓系統 氣壓系統是用壓力氣體傳遞和控制動力，正如名稱所表明的那樣，氣壓系統通常用空氣（不用其他氣體）作為樓梯介質，因為空氣是安全、成本低而又隨處可得的流體，在系統部件中產生電弧又可能點燃泄漏物的場合下（使用空氣作為介質）尤其安全。由于氣壓系統直接向大氣排氣，會產生大噪聲，因此可在氣閥和執行組件排氣口安裝消聲器來降低噪聲，以防止操作人員因接觸噪聲及高速空氣粒子又可能引發的傷害。 。因為空氣不是好的潤滑劑（包括 20%的氧氣），氣壓系統需要一個油霧器將細小的油霧注射到經過減壓閥減壓的空氣中，這有助于減少氣動組件精密配合運動件的磨損。 盡管液壓系統具有如此高性能，但它不是可以解決所有動力傳遞問題的靈丹妙藥。 2. 増力一個液壓系統（沒有使用笨重的齒輪、滑輪和杠桿）能簡單有效地將不到一盎司的力放到長生幾百噸力的輸出。 聯接件：聯接各個系統部件，為壓力流體提供功率傳輸通路，將液體返回油箱。為了合理地確定采取哪些方法，重要的是了解各種方法的顯著特征。 機床的液壓驅動具有許多優點。由電氣驅動的油泵供有傳遞能量的 油量，并可傳遞給液壓電動機或油缸，從而將液壓能轉換成機械能。這條定律指出在密封容積內壓縮的液體 —— 例如圓柱筒或管子 —— 在容積的各個不同面上作用著相等的力。也許，真正的發明家是那些農場主的妻子，因為她們經常要干重的農活。 (4) a smooth transmission, free of vibration, is required。 (3) a very pact unit is needed。當一些上進的農場主厭惡由手工沖擊、研磨谷物時，谷物的家庭養殖已開始 5000 多年。 所有的液壓系統遵守與帕斯卡定律，命名是由帕斯卡而來的，是他發明了此定律。 圖 給出了液壓元