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Landstown High School Governors STEM & Technology Academy

Landstown High School Governors STEM & Technology Academy. Advanced Robotics Chapter 6- Fluid Power Systems. Dr. Barger. Fluid Power Systems. Fluid power systems use air or liquid, or a combination of both, to transfer power. Fluid Power Systems. Transfer Methods

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Landstown High School Governors STEM & Technology Academy

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  1. Landstown High School Governors STEM & Technology Academy Advanced Robotics Chapter 6- Fluid Power Systems Dr. Barger

  2. Fluid Power Systems • Fluid power systems use air or liquid, or a combination of both, to transfer power.

  3. Fluid Power Systems • Transfer Methods • Electrical energy is often used to drive a fluid pump. • Electrical energy and mechanical motion are converted into the energy of a flowing liquid. • Hydraulic systems use oil, or other liquids, while pneumatic systems use air.

  4. Fluid Power Systems • All fluid power systems consist of: • Controls, • An energy source, • A transmission path, • A load, • Indicators,

  5. Hydraulic System Model • Hydraulic Systems are used for many applications in Robotics: • Operates motors, • Actuators, • Cylinders (load devices) • Usally electrical energy drives a pump which provides hydraulic pressure,

  6. Hydraulic System Model • Prime Mover system • A prime mover is a component of a power system that provides the initial power for movement in the system,, • The motor receives electrical energy from the source and converts it to rotary energy or movement. • The pump converts the rotary energy into fluid energy.

  7. Basic Hydraulic System LS 6-1

  8. Hydraulic System Model • Control Systems • A typical hydraulic fluid power system includes a number of control devices, • Directional control valve (DCV) (cylinders), • Pressure relief valves, • A pressure relief valve is a control device that protects the system from stress and damage caused by over pressurizing the system.

  9. Hydraulic Control Devices LS 6-2

  10. Pneumatic System Model • In a typical pneumatic system, the energy source powers a compressor which forces air into a pressurized storage tank. • The compressor is most often driven by an electric motor, or internal combustion engine. • The storage tank hold the pressurized air and acts as a reservoir for the system. • Typical uses are for: • Power tools, and • Lifting and clamping during machining operations.

  11. Pneumatic System LS 6-3

  12. Characteristics of Fluid Flow • Fluid power systems do not achieve 100 percent power transfer, • Due to friction from the cylinder walls, • This friction is known as “resistance” or power loss, • Power loss materializes primarily as heat,

  13. Pneumatic Systems • Turbulence • Refers to how the fluid moves through the fluid power system. • Conditions of the system, such as: • size and smoothness of the tubing walls, • Location and number of valves and fittings, may cause irregular flow characteristics.

  14. Pneumatic Systems • Pressure drops • Restrictions within the system are also a source of pressure drops. • These can be caused by: • Control valves, tubing length, or small tubing size • Energy Loss • As fluid pressure enters the system, it has the ability to perform a specific amount of work. • Fluid energy is lost because it is changed into heat due to friction and resistance.

  15. Pressure Drops in a Fluid System LS 6-4

  16. Pneumatic Systems • Compression of Fluids • A notable difference between hydraulic and pneumatic systems is the compressibility of the fluids, • All gases and liquids are compressible under certain conditions for each, • Hydraulic fluid is considered incompressible, • Air in pneumatic systems is readily compressible.

  17. Principles of Fluid Power • Pascal’s Law • Pressure applied to a confined fluid is transmitted, undiminished, throughout the fluid. • This pressure acts on all surfaces of the container, at right angles to those surfaces, • For this reason, the walls of the cylinder must be strong enough to withstand the pressure.

  18. Pascal’s Law LS 6-5

  19. Principles of Fluid Power • Terminology • Force • Is any factor that tends to produce or modify the motion of an object. • Inertia- the amount of force needed to produce motion (or resistance to change) of the body to be moved. • Pressure • Is the amount of force applied to a specific area. Usally in pounds per square inch (psi).

  20. Principles of Fluid Power • Fluid Power System Components • Fluid Pumps • The heart of a fluid system. It provides an appropriate flow to develop pressure. • Two general classifications: • Positive displacement pump, • Has a close clearance between the moving member and stationary pump components, • Non-Positive displacement pump • The fluid is moved by the impeller blades during each revolution.

  21. Fluid Pumps LS 6-6

  22. Principles of Fluid Power • Examples • Reciprocating pumps- Positive displacement, • Rotary Gear Pumps- positive displacement, • Rotary Vane Pumps- positive displacement, • Centrifugal pumps- non-positive displacement,

  23. Operation of a Reciprocating Pump LS 6-7

  24. Rotary Gear Pumps LS 6-8

  25. Rotary Vane Pump LS 6-9

  26. Centrifugal Pumps LS 6-10

  27. Pressure Regulator Valve Operation LS 6-11

  28. Principles of Fluid Power • Fluid Conditioning Devices • Both hydraulic fluid and air must be conditioned before being processed through a fluid power system. • Conditioning devices prolong the life of fluid power systems by removing foreign particles and moisture.

  29. Principles of Fluid Power • Hydraulic Conditioning • The number of components, types of control devices and operating environment are major considerations in hydraulic fluid conditioning. • Types used: • Strainers- Inline devices, • Filters- Inline device, • Heat exchangers- • Forced-air fans, • Water-jacket coolers, • Gas coolers.

  30. Principles of Fluid Power • Pneumatic Conditioning • Several types of devices are used but the most often is a filtering device, • Filters • Filtering must remove moisture and foreign particles, so they contain “desiccant”, which is a very dry material designed to attract moisture, • Lubricators • Lubricators are devices that add a small quantity of oil to the air after it leaves the regulator. The lubrication helps the valves and cylinders operate more efficiently.

  31. FRL Unit LS 6-12

  32. Fluid Power Systems • Control Devices • Control is achieved by devices that alter the pressure, direction and volume of fluid flow. • Pressure Control • Flow Control • Direction Control

  33. Fluid Check Valve(Pressure Control) LS 6-13

  34. Four-way Valve(Flow Control) LS 6-15

  35. Flow Control Valve Operation(Direction Control) LS 6-16

  36. Principles of Fluid Power • Load Devices • The term actuator is often used to identify the load device. • Linear Actuators • Rotary Actuators • Fluid Motors

  37. Linear Actuator LS 6-17

  38. Rotary Actuators LS 6-20

  39. Principles of Fluid Power • Hybrid Systems • A number of industrial systems produce mechanical energy by combining fluid power and electrical power systems. • Example: • Hoists use in car repair operations,

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