1. Machines UNIT 1 THE PHYSICAL WORLD OF A MACHINE Machines are a combination of different components placed together in such a way that they perform useful work. Fluid power is the engineering science that pertains to the flow of pressurized fluids.

2. Force Force is simply a “push” or a “pull.” It is linear in nature meaning “straight line” and can represent the energy of a body.

3. Measuring Force Pound Newton In our customary system of measurement, force is measured in pounds. In the metric system, force is measured in a unit called the Newton.

4. Resistance Any force that can stop or retard a body’s motion is resistance. There is a lot of resistance in fluid power systems.

5. Inertia Newton’s First Law: Inertia The tendency of a body in motion to stay in motion or a body at rest to stay at rest until acted on by a body of equal or greater mass.

6. Energy Forms The illustration shows us energy forms found in every day life. We will concern ourselves with the energy form that relates to motion control.

7. Law of Conservation Energy cannot be created or destroyed but it will change form. Heat from light bulbs Heat from friction.

8. Energy States The state of energy refers to whether it is in motion(kinetic) or stored(potential). In fluid power systems, the energy is in the form of pressurized fluids which must be in movement to accomplish any useful work.

9. Work Work is defined as moving an object over a distance. Since work is moving a object over a distance, its unit of measure is the “foot- pound.” Work=Distance moved X Force exerted

10. Power Power is defined as the rate at which energy is being produced or consumed. Power can be thought of as Work divided by Time.

11. The mathematical expression the describes power is: Power = Distance moved X Force exerted Time Horsepower can be thought of as a reference point to equate a numerical value. Horsepower = Power 550 550

12. Pressure Pressure, as it will be discussed in this class, can be thought of as the “pushing” effort produced by a fluid when a force is applied to it. Pressure = Force, in pounds/ Area, usually in square inches

13. A way to consider Force over Area is given in the following example: When a weighted object rests on a surface, its weight is divided over the surface to generate a pressure.

14. Working Energy In a fluid power system, working energy is in the form of pressurized, moving fluid. In a fluid power system, working energy changes form to perform work. The source of energy in most machines is not at the point of operation so it must be transmitted by various means. Transmission of Energy

15. Methods of transmitting Energy 1 2 3 4

16. Hydraulic and Pneumatic Transmission of Energy In Hydraulics, energy is transmitted through pressurized moving liquid. In Pneumatics, energy is transmitted through pressurized moving gas. In both systems, the movement of the fluid is referred to as “flow.” GPM = Gallons Per Minute CFM = Cubic Feet Of Air Per Minute

17. Inefficiency In fluid power systems, the energy of moving pressurized fluids changes form as the fluid meets resistance. The transformation is usually in the form of heat.