FCGear TimingGear
Appearance
|
|
| Menu location |
|---|
| Gear → Timing Gear |
| Workbenches |
| Gear |
| Default shortcut |
| None |
| Introduced in version |
| v0.16 |
| See also |
| FCGear TimingGearT |
Description[edit | edit source]
The FCGear TimingGear command creates a timing gear.
The purpose of timing gears is to allow the camshaft and crankshaft to turn the timing chain. The crankshaft turns to move pistons up and down inside the cylinders. The camshaft turns to allow intake and exhaust valves on the cylinders to open and close. These components are important for proper engine timing.
Timing gears are connected to a timing belt or timing chain.
Above: Timing gear
Usage[edit | edit source]
- Switch to the
Gear Workbench.
- There are several ways to invoke the command:
- Press the
Timing Gear button in the toolbar.
- Select the Gear →
Timing Gear option from the menu.
- Press the
- Change the gear parameter to the required conditions (see Properties).
Properties[edit | edit source]
See also: Property View.
An FCGear TimingGear object is derived from a Part Feature object and inherits all its properties. It also has the following additional properties:
Data[edit | edit source]
base
- Dataheight (
Length): Default is5 mm. Value of the gear width. - Datanum_teeth (
Integer): Default is15. Number of teeth. - Datatype (
Enumeration): Default isgt2. Type of timing gear – profile pitch for timing belts (see Notes).
computed
- Datah (
Length): (read-only) Radial height of teeth. - Dataoffset (
Length): (read-only) X-Offset of second arc mid-point. - Datapitch (
Length): (read-only) Pitch of gear. - Datar0 (
Length): (read-only) Radius of first arc. - Datar1 (
Length): (read-only) Radius of second arc. - Datars (
Length): (read-only) Radius of third arc. - Datau (
Length): (read-only) Radial difference between pitch … diameter and head of gear.
version
- Dataversion (
String):
Notes[edit | edit source]
- Datatype: The pitch of timing belts (distance from tooth centre to tooth centre of consecutive teeth) is specified in types. GT2 has a pitch of 2 mm, GT3 a pitch of 3 mm, GT5 a pitch of 5 mm etc.
Useful formulas[edit | edit source]
| Symbol | Term | Formula |
|---|---|---|
| Pitch | ||
| Pitch Diameter | ||
| Addendum Diameter | ||
| For given pitch diameters (d): | ||
| Belt Length | ||
| Axle Base | ||
| For given pitch (p) and numbers of teeth (z): | ||
| Belt Length | ||
| Axle Base |
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.CreateTimingGear.create()
gear.num_teeth = 12
gear.height = 5
gear.type = "gt5"
App.ActiveDocument.recompute()
Gui.SendMsgToActiveView("ViewFit")
