1. Compound Gear Ratios Robotics Academy 2002. All Rights Reserved.

2. Simple Gear Ratio You know how to compute the gear ratio of a single pair of gears. Gear ratio = 40 to 8 or, simplifying, 5 to 1. 40 teeth 8 teeth

3. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio A gear box with more than one pair of gears is called a compound gear box. A compound gear ratio is the overall gear ratio of the compound gear box.

4. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio To compute a compound gear ratio, we must first find the gear ratios of each individual pair of gears. What is the gear ratio of this pair of gears? Answer: 3 to 1

5. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio What is the gear ratio of this pair of gears? Answer: 3 to 1

6. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio If this axle were to make 90 rotations, how many rotations would this axle make? Answer: 30

7. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio And if this axle were to make 30 rotations, how many rotations would this axle make? Answer: 10

8. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio 9030 10 What does that imply about what the overall gear ratio is?

9. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio Answer: 9 to 1 To compute the compound gear ratio, we multiply the gear ratios of each pair of gears in the gear box. (3 to 1) x (3 to 1) = 9 to 1

10. Robotics Academy 2002. All Rights Reserved. Compound Gear Ratio What is the compound gear ratio of this gear box going from bottom to top? Gear ratio 1: 5 to 1 Gear ratio 2: 3 to 1 Gear ratio 3: 3 to 1 Answer: 45 to 1