How to Make a Helical Gear

In this Instructable I will demonstrate how to make a Helical Gear in Fusion 360 using a simple Add-in. First a very brief overview of Helical Gears;

A Helical gear is a type of cylindrical gear with a slanted tooth trace. Compared to spur gears, they have a larger contact ratio and excel in quietness and less vibration and are able to transmit large forces of energy. These gears are incredibly popular in mechanical engineering, they are commonly found in the Manual Transmission of a car.

Fusion 360

First go to this link; Helical Gears here you will be given the choice to download the file for either Windows or Mac. Next select Download and wait for the file to download, once the file has downloaded open it and follow the installation steps. This should take 2 minutes at most.

Once the installation is complete, open Fusion 360 and navigate to the "Tools" then "Add-ins" in the top Menu. Next a window should open, select the "Add-ins" and navigate to "HelicalGear". If the script isn't already running then select "Run".

Go to "Solid" then "Create" and at the very bottom will be a tool called "Helical Gear". When you select this tool a window will open. Before we continue you need to know what these different parameters mean.

The pressure angle dictates the shape of the teeth. At a low pressure angle, the teeth have more contact with each other but that means more noise and backlash (space between meshed teeth, not good). The higher pressure angles provide less contact, so they are smoother and quiet.

Handedness in helical gears refers to the direction the teeth lean when the gear is placed flat on a table.

By setting a helix angle of 0 degrees, Spur gears can be created and defined in the metric system (as opposed to the sample Spur Gear script which defines gears in the American system) with this add-in. The Helix angle is the degree of twist on the gear

Backlash, a clearance between mating gear teeth, is built into speed reducers to let the gears mesh without binding and to provide space for a film of lubricating oil between the teeth. This prevents overheating and tooth damage.

Module, the module is the length of pitch diameter per tooth. Therefore m = d / z; where m is the module, d is the pitch diameter of the gear and z is the number of teeth.

Finally, Pressure Angle, The most common value for pressure angle is 20°, the second most common is 14.5°.The pressure angle defines the angle of the line of action which is a common tangent between the two base circles of a pair of gears, The short of it is this: leave this value at 20 degrees until you have a reason to do otherwise - but know that any pair of gears MUST have the same pressure angle.

After entering you parameters now you can click OK and you've made your Helical Gear!

If you have any other questions regarding the parameters or terms feel free to comment below asking.