液压与气动系统

液压与气动系统 (中文5300字,英文3500字)
仅有以下三种基本方法传递动力：电气、机械和流体。大多数应用系统实际上是将三种方法组合起来而得到最有效地最全面的系统。为了合理地确定采取哪种方法，重要的是了解各种方法的显著特征。例如液压系统在长距离上比机械系统更能经济地传递动力。然而液压系统与电气系统相比，传递动力的距离较短。液压动力传递系统涉及电动机、调节装置和压力，流量控制。总的来说，该系统包括：
l 泵：将原动机的能力转换成作用在执行部件上的液压能。 
2 阀：控制泵产生流体的运动方向、产生的功率的大小，以及到达执行部件液体的流量。功率大小取决于对流量和压力大小的控制。  
3 执行部件：将液压能转换成可用的机械能。  
4 介质即油液：可进行无压缩传递和控制，同时可以润滑部件，使阀体密封和系统冷却。
5联接件：联接各个系统部件，为压力流体提供功率传输通路，将液体返回邮箱。 

Hydraulic System
     There are only following three basic methods of transmitting power : electrical，mechanical ,and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to understand the characteristic of each method. For example，hydraulic systems on the long distance economically deliver power more than mechanical systems. However, fluid systems are restricted to shorter distances than electrical systems. Hydraulic power transmission systems are concerned with the generation, modulation, and control of sculptress and flow, and in general such systems include:
 l. Pumps convert available power from the prime mover to hydraulic power at the actuator.   
 2. Valves control the direction of pump- flow, the level of produced power, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.
 3. Actuators convert hydraulic power to usable mechanical power output at the point required.   
 4. The medium is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.   
 5.Connectors link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank（reservoir).