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

Locomotives: Multiple Mechanisms

Toy Car: Rear End Gear Train Front End Steering Gears