Mechanical Gears and Energy Transfer Technology 8.
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Transcript of Mechanical Gears and Energy Transfer Technology 8.
Mechanical Gears and Energy Transfer
Technology 8
What is energy?
• Energy is the ability to do work.
• Energy can be– Kinetic- the energy of motion.– Potential- “waiting” energy.
Kinetic and Potential Energy
Some Types of Energy
• Chemical (food energy)
• Light (solar)
• Electrical (electrons moving through wires)
• Mechanical (movement of objects)
• Nuclear (energy in nucleus of an atom)
First Law of Thermodynamics
• Energy cannot be created nor destroyed.
• Energy can be transferred.
Mechanisms
• Can be used to change energy by transferring its direction, speed, type of movement and force or torque.
• Common mechanisms are:– Bicycle– Eggbeater
• Mechanisms can work alone, in pairs, or systems.
Gears
• Gears redirect the applied force so that mechanisms can accomplish their tasks.
• Gears come in all sizes.
• Some gears are covered, some aren’t.
• Some require a lot of maintenance, some very little.
Input
• Each mechanism has an initial force which starts the “working process”.
• This is the input.
Output
• The motion and force which occurs as a result of the input.
Uses of gears
• Gears or pulley systems allow a change in speed, torque, force, type of movement and direction.
• This is a common problem in automobiles, airplanes, robots and mechanical tools.
Force
• That which causes an object with mass to accelerate.
Torque
• A force that causes a rotation around a central point, such as an axis.
Relationship Between Torque and Speed
• There is an “opposite” relationship between torque and speed.
• Increase in torque means decrease in speed.
• Decrease in torque means increase in speed.
Calculating Gear Ratios
• Gear Ratio = # of teeth on output gear / # of teeth on input gear
• As the size of the driven gear decreases in relation to the size of the driving gear, output speed increases.
• As the size of the driven gear increases in relation to the driving gear, output torque increases.
Hand Mixer: Crown & Pinion Gear
Electric Motor: Gear Train
Antique Jack: Bevel Gear and Worm Gear
Ice Cream Scoop: Rack & Pinion
Paper Transport Rollers Simple Gear Train with Idler
Stapler: Multiple Mechanisms
Toy Telephone: Rack & Pinion
Rearview Mirror Motors: Rack & Pinion
Fishing Reel: Crown & Pinion
Electric Mixer: Worm & Wheel
Food Processor: Planetary Gears