PartDesign InvoluteGear

Description
This tool allows you to create a 2D profile of an involute gear. This 2D profile is fully parametric, and can be padded with the PartDesign Pad or PartDesign AdditiveHelix feature.

For more detailed information see Wikipedia's entries for: Gear and Involute Gear



Create the Profile

 * 1) Go to the menu.
 * 2) Set the Involute parameters.
 * 3) Click
 * 4) The involute gear is created outside of the active body. Drag and drop it into a body for the application of further features like padding.

Create a Spur Gear

 * 1) Select the gear profile in the tree.
 * 2) Press the  button.
 * 3) Set the pad's  to the desired face width of the gear.
 * 4) Click

Create a Helical Gear

 * 1) Select the gear profile in the tree.
 * 2) Press the  button.
 * 3) Choose as Axis the normal of the gear profile, that is Normal sketch axis . (In earlier versions the Base Z axis can be used as long as the profile's plane has not been altered.)
 * 4) Choose a Height-Turns mode.
 * 5) Set the  to the desired face width of the gear.
 * 6) To set the desired helical angle an Expressions for the  is required.
 * 7) Click the blue [[Image:Sketcher_Expressions.png|16px]] icon at reh right of the turns' input filed
 * 8) Enter the following formula:, where  is an example for the desired helical angle (aka beta-value) and  is the Name of the profile.
 * 9) Click  to close the formula editor.
 * 10) Click  to close the  AdditiveHelix' task panel.

Hint: To make the helical angle an accessible parameter, use a dynamic property:
 * 1) In the profile's property editor, activate the  option in the context menu.
 * 2) Again in the contest menu, select . Note: this entry is only available when  is active!
 * 3) In the "Add Property" dialog
 * 4) Choose  as Type.
 * 5) Set "Gear" as Group.
 * 6) Set "HelicalAngle" as Name (without space).
 * 7) Click
 * 8) Now a new property "Helical Angle" (space added automatically), with an initial value of, becomes available.
 * 9) Assign the desired helical angle to the new property.
 * 10) In the formula of the AdditiveHelix'  property, you can now reference  instead of the hard coded value of e.g. ; again assuming  as the Name of the profile.

Parameters

 * Number of teeth: Sets the number of teeth.


 * Modules: Pitch diameter divided by the number of teeth.


 * Pressure angle: Acute angle between the line of action and a normal to the line connecting the gear centers. Default is 20 degrees. (More info)


 * High precision: True or false


 * External gear: True or false

Tutorials
How to make gears in FreeCAD

Related

 * FCGear Workbench