FCGear WormGear: Difference between revisions
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# Invoke the command several way: |
# Invoke the command several way: |
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#* Press the [[File:FCGear_WormGear.svg|22px|link=FCGear WormGear]] [[FCGear_WormGear|Create a Worm gear]] button in the tool bar. |
#* Press the [[File:FCGear_WormGear.svg|22px|link=FCGear WormGear]] [[FCGear_WormGear|Create a Worm gear]] button in the tool bar. |
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#* Using the {{MenuCommand|Menu → Worm gear}}. |
#* Using the {{MenuCommand|Gear Menu → Worm gear}}. |
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# Change the gear parameter to the required conditions (see {{Emphasis|Properties → Data}} below). |
# Change the gear parameter to the required conditions (see {{Emphasis|Properties → Data}} below). |
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Revision as of 14:25, 4 April 2020
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Menu location |
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FCGear → Create a Worm gear |
Workbenches |
FCGear |
Default shortcut |
None |
Introduced in version |
v0.16 |
See also |
PartDesign InvoluteGear |
Description
The worm can be considered a special case of a helical gear. Imagine that there is only one tooth on a spur gear. Now increase the helix angle so much that the tooth winds around the spur gear several times before it emerges on the opposite side. The result would be a single thread worm.
For a single-start worm, each full turn (360 degrees) of the worm advances the gear by one tooth. So a gear with 24 teeth will provide a gear reduction of 24:1. For a multi-start worm, the gear reduction equals the number of teeth on the gear, divided by the number of starts on the worm.
A worm can only be used with a worm wheel. This is called a worm drive. Like other gear arrangements, a worm drive can reduce rotational speed or transmit higher torque. One of the major advantages of worm gear drive units are that they can transfer motion in 90 degrees. A worm drive is also self-locking.
Usage
- Switch to the
FCGear Workbench.
- Invoke the command several way:
- Press the
Create a Worm gear button in the tool bar.
- Using the Gear Menu → Worm gear.
- Press the
- Change the gear parameter to the required conditions (see Properties → Data below).
Properties
Data
Base
- DataPlacement: Placement is the location and orientation of an object in space.
- DataLabel: User name of the object in the Tree view.
gear_parameter
- Databeta: Lead angle (not changeable, is calculated automatically).
- Datadiameter: Pitch diameter.
- Dataheight: Value of the worm length.
- Datamodule: Module is the ratio of the reference diameter of the gear divided by the number of teeth (see also the information in Notes).
- Datateeth: Number of teeth (see also the information in Notes)
involute_parameter
- Datapressure_parameter: Default is 20 (see also the information in Notes).
View
The parameter descriptions of the View tab will be found in Property editor, further below at Example of the properties of a PartDesign object.
Notes
- module: Using ISO (International Organization for Standardization) guidelines, Module size is designated as the unit representing gear tooth-sizes. Module (m): m = 1 (p = 3.1416), m = 2 (p = 6.2832), m = 4 (p = 12.566). If you multiply Module by Pi, you can obtain Pitch (p). Pitch is the distance between corresponding points on adjacent teeth. If the module is changed, the lead angel also changes (beta).
- teeth: The number of teeth in a worm is called the number of threads. Correspondingly, one speaks of single, double or multiple thread worms. In general, mainly single worms are produced, but in special cases the number of starts can be up to four. If the number of teeth is changed, the lead angel also changes (beta).
- pressure_parameter: Only change the parameter, if sufficient knowledge of the gear geometry is available.
Limitations
Limitation are not known yet.
Worm wheel
The worm wheel must be designed manually. For this purpose FCGear InvoluteGear can be used for a simple construction. In any case, in-depth knowledge of the gear types is required.