Module 3 - Design of Mechanical Elements
Chapter 13: Gears
Chapter 13 Overview
Chapter 13 covers the following key concepts:
- Types of gears
- Contact ratio
- Gear trains
- Force analysis
Lecture 22A
In case you missed it, here's a video of the first part of Lecture 22. In this video, we introduce the fundamentals of gears - a key component in mechanical power transmission.
Lecture 22B
In case you missed it, here's a video of the second part of Lecture 22. In this video, we break down the essential terminology used in spur gear design.
Lecture 22C
In case you missed it, here's a video of the third part of Lecture 22. In this video, we dive into the geometry gear tooth profiles, focusing on one of the most important concepts in gear design: the involute curve.
Lecture 22 Tasks
The below assignments will guide you through an introduction to gears.
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Read
- Sections 13.1-13.12 of Shigley's Mechanical Engineering Design.
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Watch
- Mechanical gears in jumping insects: Nature is the world's greatest engineer. Watch this professor discuss the existence of mechanical gears in insects.
- Working Gears Evolved in Plant-Hopping Insect - by Scientific American: Here's another video about these insects.
- DANotes: Spur Gears: Gear meshing: Watch the animation on this page of two spur gears meshing.
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Practice
- Problems 13-1, 13-3, and 13-8 from Shigley's Mechanical Engineering Design, and then review the solutions posted.
Lecture 22 Notes
Lecture 23A
In case you missed it, here's a video of the first part of Lecture 23. In this video, we dive into the design considerations that make gear teeth mesh smoothly - or not...
Lecture 23B
In case you missed it, here's a video of the second part of Lecture 23. In this video, we study how gear trains are used to achieve specific speed and torque outputs.
Lecture 23C
In case you missed it, here's a video of the third part of Lecture 23. In this video, we cover epicyclic gear trains, which are compact gear systems that can deliver different speeds, directions and torque outputs - all at once.
Lecture 23 Tasks
In this lecture, we will look at geartrains and the interactions between different gears.
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Read
- Sections 13.6-13.7 and 13.13 of Shigley's Mechanical Engineering Design.
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Watch
- What makes planetary gearboxes so amazing?: This video demonstrates how many different gear ratios are possible with even a simple version of epicyclic gear sets (starting around 4:46).
- Shredding Paper with Lego Gears (ver 2): Watch someone design a paper shredder using lego gears.
- Notice how the reaction forces in the gears cause the structure to bend and separate, particularly in the early interation of the design.
- Around 2:00, see how a single power input can be split in a gear train to create different gear ratios.
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Practice
- Problem 13-17 from Shigley's Mechanical Engineering Design, and then review the solutions posted.
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Complete
- Lecture 23 Quiz, due Thursday April 17 at 11:59 PM.