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FCGear CycloidRack

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FCGear CycloidRack

Menu location
Gear → Cycloid Rack
Workbenches
Gear
Default shortcut
None
Introduced in version
1.0
See also
FCGear CycloidGear

Description[edit | edit source]

The FCGear CycloidRack command creates a cycloid gear rack with spur gearing by default that can also be transformed into a helical gearing or a double helical gearing.

Cycloid racks from left to right: Spur gearing, helical gearing, double helical gearing

Usage[edit | edit source]

  1. Switch to the Gear Workbench.
  2. There are several ways to invoke the command:
    • Press the Cycloid Rack button in the toolbar.
    • Select the Gear → Cycloid Rack option from the menu.
  3. Change the gear parameter to the required conditions (see Properties).

Properties[edit | edit source]

See also: Property View.

An FCGear CycloidRack object is derived from a Part Feature object and inherits all its properties. It also has the following additional properties:

Data[edit | edit source]

accuracy

  • Datanumpoints (Integer): Default is 15. Number of points for spline.

base

  • Dataadd_endings (bool): If true (default), then the total length of the rack is teeth * pitch. If false, then the rack starts with a tooth-flank.
  • Dataheight (Length): Default is 5 mm. Value of the gear width.
  • Datanum_teeth (Integer): Default is 15. Number of teeth.
  • Datarack (PythonObject): Python gear object.
  • Datathickness (Length): Default is 5 mm. Thickness of the uncut part of the rack.

computed

  • Datatransverse_pitch (Length): (read-only) Pitch in the transverse plane.

cycloid

  • Datainner_diameter (Float): Default is 7.5. Diameter of the rolling circle of hypocycloid, normalized by the Datamodule (see Notes).
  • Dataouter_diameter (Float): Default is 7.5. Diameter of the rolling circle of epicycloid, normalized by the Datamodule (see Notes).

fillets

  • Datahead_fillet (Float): Default is 0.
  • Dataroot_fillet (Float): Default is 0.

helical

  • Datadouble_helix (Bool): Default is false, true creates a double helix rack (see Notes).
  • Datahelix_angle (Angle): Default is . With the helix angle β a helical rack is created (positive value → rotation direction right, negative value → rotation direction left).

involute

  • Datamodule (Length): Default is 1 mm. The module multiplied by Pi equals the pitch, the distance between corresponding points on adjacent teeth (see Notes).

precision

  • Datasimplified (Bool): Default is false. If true the rack is drawn with a constant number of teeth to avoid topological renaming.

tolerance

  • Dataclearance (Float): Default is 0.25 (see Notes).
  • Datahead (Float): Default is 0. Additional length of the tip of the teeth, normalized by the Datamodule.

version

  • Dataversion (String):

Notes[edit | edit source]

See FCGear CycloidGear.

Useful formulas[edit | edit source]

See FCGear CycloidGear.

Scripting[edit | edit source]

Use the power of Python to automate your gear modeling:

import FreeCAD as App
import FreeCADGui as Gui
import freecad.gears.commands
gear = freecad.gears.commands.CreateCycloidRack.create()
gear.num_teeth = 20
gear.helix_angle = 20
gear.height = 10
gear.double_helix = True
App.ActiveDocument.recompute()
Gui.SendMsgToActiveView("ViewFit")