Assistente de projeto de engrenagem envolvente

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Sprocket

Shaft design wizard

PartDesign

Menu location
PartDesign InvoluteGear
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

Optionally activate the correct body.
Go to the menu Part Design → Involute gear....
Set the Involute parameters.
Click OK.
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

Select the gear profile in the tree.
Press the PartDesign Pad button.
Set the pad's DadosLength to the desired face width of the gear.
Click OK

Create a helical gear

introduced in version 0.19

Select the gear profile in the tree.
Press the PartDesign AdditiveHelix button.
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.)
Choose a Height-Turns mode.
Set the DadosHeight to the desired face width of the gear.
To set the desired helical angle an Expressions for the DadosTurns 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 DadosName of the profile.
3. Click OK to close the formula editor.
Click OK to close the task panel.

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

Select the profile.
In the Property editor activate the Show all option in the context menu.
Again in the context menu, select Add Property. Note: this entry is only available when Show all is active.
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
Now a new property DadosHelical Angle (space added automatically), with an initial value of 0.0°, becomes available.
Assign the desired helical angle to the new property.
In the formula of the DadosTurns 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 DadosName of the profile.