Difference between revisions of "PartDesign InvoluteGear"

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(Add a note about using a dynamic property for the helical angle)
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## Click the blue [[Image:Sketcher_Expressions.png|16px]] icon at reh right of the turns' input filed
 
## Click the blue [[Image:Sketcher_Expressions.png|16px]] icon at reh right of the turns' input filed
 
## Enter the following formula: {{incode|Height * tan(25°) / (InvoluteGear.NumberOfTeeth * InvoluteGear.Modules * pi)}}, where {{incode|25°}} is an example for the desired helical angle (aka beta-value) and {{incode|InvoluteGear}} is the [[Object_name|Name]] of the profile.
 
## Enter the following formula: {{incode|Height * tan(25°) / (InvoluteGear.NumberOfTeeth * InvoluteGear.Modules * pi)}}, where {{incode|25°}} is an example for the desired helical angle (aka beta-value) and {{incode|InvoluteGear}} is the [[Object_name|Name]] of the profile.
 +
## Click {{Button|OK}} to close the formula editor.
 +
# Click {{Button|OK}} to close the  AdditiveHelix' task panel.
  
 
Hint: To make the helical angle an accessible parameter, use a ''dynamic property'':
 
Hint: To make the helical angle an accessible parameter, use a ''dynamic property'':
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## Set "Gear" as Group.
 
## Set "Gear" as Group.
 
## Set "HelicalAngle" as Name (without space).
 
## Set "HelicalAngle" as Name (without space).
 +
## Click {{Button|OK}}
 
# Now a new property "Helical Angle" (space added automatically), with an initial value of {{incode|0.0°}}, becomes available.
 
# Now a new property "Helical Angle" (space added automatically), with an initial value of {{incode|0.0°}}, becomes available.
# In the formula of the AdditiveHelix' {{PropertyData|Turns}} property, you can now reference {{incode|InvoluteGear.HelicalAngle}} instead of the hard coded value {{incode|25°}} from the previous step; again assuming {{incode|InvoluteGear}} as the [[Object_name|Name]] of the profile.
+
# Assign the desired helical angle to the new property.
 +
# In the formula of the AdditiveHelix' {{PropertyData|Turns}} property, you can now reference {{incode|InvoluteGear.HelicalAngle}} instead of the hard coded value of e.g. {{incode|25°}}; again assuming {{incode|InvoluteGear}} as the [[Object_name|Name]] of the profile.
  
 
== Parameters == <!--T:17-->  
 
== Parameters == <!--T:17-->  

Revision as of 20:06, 26 December 2021

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PartDesign InvoluteGear.svg 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

PartDesign Involute Gear 01.png

Usage

Create the Profile

  1. Go to the menu Part Design → PartDesign InternalExternalGear.svg Involute gear....
  2. Set the Involute parameters.
  3. Click OK
  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 PartDesign Pad.svg 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.svg 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 16px icon at reh right of the turns' input filed
    2. Enter the following formula: Height * tan(25°) / (InvoluteGear.NumberOfTeeth * InvoluteGear.Modules * pi), where 25° is an example for the desired helical angle (aka beta-value) and InvoluteGear is the Name of the profile.
    3. Click OK to close the formula editor.
  7. Click OK 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 Show all option in the context menu.
  2. Again in the contest menu, select Add Property. Note: this entry is only available when Show all is active!
  3. In the "Add Property" dialog
    1. Choose App::PropertyAngle as Type.
    2. Set "Gear" as Group.
    3. Set "HelicalAngle" as Name (without space).
    4. Click OK
  4. Now a new property "Helical Angle" (space added automatically), with an initial value of 0.0°, becomes available.
  5. Assign the desired helical angle to the new property.
  6. In the formula of the AdditiveHelix' DataTurns property, you can now reference InvoluteGear.HelicalAngle instead of the hard coded value of e.g. 25°; again assuming InvoluteGear 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