Fluid Power Systems - Pirate Nation Engineering：流体动力系统的海盗的国家工程.pdf

Fluid Power Systems What Are Fluid Power Systems  Involves the transfer of mechanical energy  Because much of the system is a liquid and not a solid part, fluid power systems have a long life expectancy.  Two main types of fluid power systems  Hydraulic power system  Pneumatic power system Why Use Fluid Power  An almost unlimited amount of power can be produced and maintained in a fluid power system  Easy and complete control over a wide range of power in a fluid system. This allows for smooth, quick control of energy transfer  A characteristic of the fluids used is that they have a natural springiness, which produces a cushioning effect that reduces shock in the system.  The component in fluid power systems can be located far apart and power can be transferred quickly, with little power loss in the system. Fluids exert pressure  Pressure is a force acting upon an area.  Liquids exert pressure in all directions  Pressure is caused by the amount (weight) of liquid in a container, more pressure is exerted on the containers lower sides. How fluids act  Water seeks its own level  Water and other fluids will flow from high pressure to low pressure and continue to flow until both pressures are equal. Blaise pascal and mechanical advantage  Over 350 years ago, Pascal discovered that liquids in a closed container distributed pressure in all directions equally inside the container.  These properties are what make hydraulic devices capable of increasing mechanical advantage. Comparing liquids and gases  Liquids and gases act differently because the molecules in liquid are closer together than the molecules in gases.  Compressibility- how much of any matter can be squashed into a smaller size (volume)  Liquids even under e