PartDesign InvoluteGear

Sprocket

Shaft design wizard

PartDesign

PartDesign InvoluteGear
Menu location
Part Design → Involute gear...
Workbenches
PartDesign
Default shortcut
None
Introduced in version
-
See also
FCGear Workbench

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

Usage

Create the profile

1. Optionally activate the correct body.
2. Go to the menu Part Design → Involute gear....
3. Set the Involute parameters.
4. Click OK.
5. If there was no active body: drag and drop the gear 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 PartDesign Pad button.
3. Set the pad's DataLength to the desired face width of the gear.
4. Click OK

Create a helical gear

introduced in version 0.19

1. Select the gear profile in the Tree.
2. Press the PartDesign AdditiveHelix button.
3. Choose as Axis the normal of the gear profile, that is Normal sketch axis introduced in version 0.20. (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 DataHeight to the desired face width of the gear.
6. To set the desired helical angle an Expressions for the DataTurns is required.
   1. Click the blue icon at the right of the input field.
   2. Enter the following formula: Height * tan(25°) / (InvoluteGear.NumberOfTeeth * InvoluteGear.Modules * pi), where 25° is an example for the desired helical angle (also known as beta-value) and InvoluteGear is the DataName of the profile.
   3. Click OK to close the formula editor.
7. Click OK to close the task panel.

Hint: To make the helical angle an accessible parameter, use a dynamic property:

1. Select the profile.
2. In the Property editor activate the Show all option in the context menu.
3. Again in the context menu, select Add Property. Note: this entry is only available when Show all is active.
4. In the Add Property dialog:
   1. Choose App::PropertyAngle as Type.
   2. Set Gear as Group.
   3. Set HelicalAngle as Name (without a space).
   4. Click OK
5. Now a new property DataHelical Angle (space added automatically), with an initial value of 0.0°, becomes available.
6. Assign the desired helical angle to the new property.
7. In the formula of the DataTurns property of the AdditiveHelix, you can now reference InvoluteGear.HelicalAngle instead of the hard coded value of e.g. 25°; again assuming InvoluteGear is the DataName of the profile.

Properties

• DataExternal Gear: True or false

• DataHigh Precision: True or false

• DataModules: Pitch diameter divided by the number of teeth.

• DataNumber Of Teeth: Sets the number of teeth.

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

Tutorials

How to make gears in FreeCAD

Related

• FCGear Workbench

Sprocket

Shaft design wizard

PartDesign

PartDesign

• Structure tools: Part, Group
• Helper tools: Create body, Create sketch, Edit sketch, Map sketch to face

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• Modeling tools
  • Datum tools: Create a datum point, Create a datum line, Create a datum plane, Create a local coordinate system, Create a shape binder, Create a sub-object(s) shape binder, Create a clone
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  • Subtractive tools: Pocket, Hole, Groove, Subtractive loft, Subtractive pipe, Subtractive helix, Subtractive box, Subtractive cylinder, Subtractive sphere, Subtractive cone, Subtractive ellipsoid, Subtractive torus, Subtractive prism, ‎Subtractive wedge

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• Transformation tools: Mirrored, Linear Pattern, Polar Pattern, Create MultiTransform, Scaled
• Dress-up tools: Fillet, Chamfer, Draft, Thickness
• Boolean: Boolean operation

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• Extras: Migrate, Sprocket, Involute gear, Shaft design wizard
• Context menu: Set tip, Move object to other body, Move object after other object, Appearance, Color per face

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