Wonders Of Gear

Understanding Gear Concepts: Module, Pitch Circular Diameter, and Their Interrelationships

Gear Module defines the size of the teeth on a gear, measured in millimeters (mm). Larger modules mean larger teeth, and gears that mesh must share the same module size. Pitch Circular Diameter (PCD) is the imaginary circle through the contact points between meshing gears, representing the point of effective diameter for transferring motion and work.

The relationships between module (m), number of teeth (z), and PCD are as follows: PCD=module × number of teeth. This equation highlights that the PCD increases with both the module and the number of teeth, influencing the size and compatibility of gears in a system.

Gear Ratios, Output Speed, and Torque

The gear ratio (speed ratio) determines the relationship between input and output speed and torque in a pair of gears. The gear ratio is derived from the number of teeth on the driven gear compared to the driving gear: Gear Ratio = Teeth on Driven Gear/Teeth on Driving Gear

A higher gear ratio reduces output speed but increases torque, which is important for this applications requiring more force, like lifting objects.

Improving a Hand-Squeezed Fan Design

To enhance the hand-squeezed fan, I would focus on optimizing the gear arrangement to increase fan blade speed while minimizing resistance. Below is a simple sketch:

Using a compound gear train could help achieve the desired speed, as smaller driving gears paired with larger output gears will boost rotation speed without requiring additional input force. Due to the gear ratio, less energy is needed to complete on full revolution.

Final combination;

Practical Activity: Arranging Gears to Lift a Water Bottle

During the practical, our team arranged a gear system to lift a water bottle, focusing on maximizing the mechanical advantage with the available gears to find the best gear ratio suited for the experiment.

1. Gear Ratio Calculation: We calculated the speed ratio by dividing the number of teeth on the output gear by the input gear’s teeth, aiming for a high gear ratio to lift the bottle with minimal effort.

   

2. Gear Layout:

   Sketch;

   

   Build;

   

3. Revolution Calculation: We calculated the number of crank handle rotations needed to lift the bottle a certain height. For lifting the bottle 200mm required approximately x revolutions based on the diameter of the winch and gear arrangement.

   

   
   

4. Video of Gear Operation: (Include a video showcasing the smooth turning of the gears, emphasizing the arrangement’s effectiveness)

Through trial and error, we found that reducing friction between gear teeth was crucial for smooth rotation, experimenting with alignment adjustments and tighter connections without lubrication.

How smooth the gear was;

1. Reflection on Learning

   This hands-on activity helped me better grasp gear mechanics, particularly how gear ratios affect speed and torque. Experimenting with different layouts taught me how theoretical calculations translate into real motion and the value of accurate assembly in reducing friction. This experience has given me more confidence in using gear systems for future design projects, particularly in balancing power and efficiency.