Lesson 3: Designing 3D Gears

Introduction to Gears

Lesson 3: Designing 3D Gears

Mechanism of a bicycle

Creating a Simple Machine

Lesson 3: Designing 3D Gears

Designing an 8 -Tooth Gear

Lesson 3: Designing 3D Gears

create an 8-tooth gear body

When you have multiple bodies in a design, it can be diicult to keep track of which boy represents what part of the project

Lesson 3: Designing 3D Gears

add an involute gear

Lesson 3: Designing 3D Gears

make the gear 3D

Lesson 3: Designing 3D Gears

Designing a 24-Tooth Gear

Lesson 3: Designing 3D Gears

add an involute gear

Setting the module to 1.00 mm means that the gear teeth will be 1.00 mm wide and 1.00 mm high

Lesson 3: Designing 3D Gears

make the gear 3D

Lesson 3: Designing 3D Gears

Gears Engagement

Lesson 3: Designing 3D Gears

Moving the small Gear

If the center distance between two gears is incorrect, the gears will not mesh properly and will not transfer power eiciently

Lesson 3: Designing 3D Gears

Rotating the small Gear

Lesson 3: Designing 3D Gears

Making Holes in the Gears

Lesson 3: Designing 3D Gears

create a circle

Lesson 3: Designing 3D Gears

create a hole

Lesson 3: Designing 3D Gears

Crea琀椀ng a hole

To zoom in and out, you can scroll the mouse wheel up and down, or use the zoom buttons on the toolbar.

View options

Lesson 3: Designing 3D Gears

Making a Hole in the Big Gear

Lesson 3: Designing 3D Gears

create a circle:

Lesson 3: Designing 3D Gears

create a hole

Lesson 3: Designing 3D Gears

Designing a Base to Connect the Gears

The proper alignment of the gears is critical for eective teeth meshing

Lesson 3: Designing 3D Gears

create a sketch

Lesson 3: Designing 3D Gears

create a rectangle

Not all sketches need to be fully constrained. In some cases

Lesson 3: Designing 3D Gears

create a 3D shape

Lesson 3: Designing 3D Gears

create a sketch in the top surface of the Base

Lesson 3: Designing 3D Gears

create the big circle

Lesson 3: Designing 3D Gears

create the center of the small circle

Lesson 3: Designing 3D Gears

create the small circle

Lesson 3: Designing 3D Gears

create the cylinders

Lesson 3: Designing 3D Gears

move the Gears

Lesson 3: Designing 3D Gears

make the base curved:

Lesson 3: Designing 3D Gears

save your file:

Lesson 3: Designing 3D Gears

Read the sentences and tick True or False Gears work together and can transmit power and motion

What are gears and how do they work

Lesson 3: Designing 3D Gears

Explain how the gears work on a bicycle

What is the importance of determining the center distance between two gears

Search the Internet to find applications which use involute gears. Describe two applications and explain the characteristics of involute gears

Lesson 3: Designing 3D Gears

Use the tools from this unit to create the following model in FreeCAD. The following measurements will help you understand how each side is created.

Use the formula for the gear ratio to calculate the ratio for each combination of gears. Mark with a tick true which combinations of gears give increased speed and which give increased torque