Mechanisms- Gears and Gear Trains

Day 5 (2/9/16)

Gears are fascinating mechanisms. Individually they seem so simple, but together they can do very complex tasks. There are so many different ways that gears can be arranged to work together as a gear train. But what I think is the most interesting about them is that they are used everywhere for so many different tasks.

Gears are pieces that have teeth along the outside so that when they engage with another gear the teeth can interlock and rotate without slipping. Many gears are circle shaped like the one on the right. However, gears can also take on the form of ovals, squares, triangles and other random shapes. As long as they can spin, they stay in contact with another gear(s) at all times, and they have teeth that wont slip when they come in contact with other gears they will be functional and useful. Gear trains are arrangements of different gears that are used to perform a certain function.

Gear trains can be arranged in many different ways with specific names for different kinds of arrangements. While there are many different arrangements, I want to specifically talk about
planetary gear wheel trains. A planetary gear wheel train has elements and iterations of a central gear, sometimes called "the sun," an outer ring gear, and central intermediate gear(s), often called "planets." Out of the three different types of pieces, one of them must be fixed. For example, the planetary gear wheel train on the left has its center "sun" fixed in the middle and the outer ring fixed. The intermediate "planet" gear gets spun around the sun in the middle and rides along the outer ring. Planetary gear wheel trains can be much more complicated than this model too.

Gear trains, especially planetary gear wheel trains have a variety of uses. They are used in the transmissions of modern cars as well as for speed reduction in robotics and control actuated machines. They are also used in electric screw drivers and bulldozer power trains (http://machinedesign.com/motion-control/world-planetary-gears).

Gears are useful and timeless mechanisms that I believe will always have an impact on society and technology. With so many uses and a arrangements, they can be used in almost an infinite amount of situations and accomplish almost an infinite amount of tasks.