Creating a Worm Drive using DesignSpark Mechanical
DesignSpark Mechanical is a fantastic free-to-use 3D CAD design software, if you need to brush up on your skills or if you are an entirely new user stuck on how to create a worm drive, this quick tutorial, plucked from Zendesk, is just the thing.
There are plenty more tutorials just like this one that can be found in the DesignSpark Mechanical Zendesk Support area.
1. Sketch the profile for the screw and the wheel. As an example, we used these:
2. Convert them into solids with the PULL tool:
3. For the wheel/worm gear, the following profile is sketched onto a grid placed slightly above the tangent of the cylinder with a larger radius. You may also use the spline tool to add more of a curve.
4. Use the 'project' tool to align these segments onto the curved surface.
5. Select this new surface patch and click on the 'move' tool. Drag the move handle to the centre of the grid and tick the 'pattern' box under the tool options.
Now, drag the rotational handle along the z-axis (blue colour) to replicate the surface patch 50 times along the circumference of the wheel. This will form the teeth of the wheel. You can select a lower count (25/30) to get a less dense teeth pattern (like the model at the top).
6. Using the Pull tool, either drag the teeth pattern outwards or inwards from the centre of the wheel.
In this example, we drag inwards.
7. Go back to step 3 where we sketched the tooth profile. We use this as a reference to create a shape for the screw thread.
8. Use the CTRL key and move tool, copy this shape and align to the length cross-section of the cylindrical screw.
9. Switch to 3D mode and then using the PULL tool, revolve this shape as a left-handed helix along the length of the cylinder. Enter the value of the pitch as the width of a tooth on the wheel.
10. With the screw and the wheel complete, feel free to assemble them according to your design requirements.
If you haven't downloaded DesignSpark Mechanical yet, what are you waiting for!?
CommentsAdd a comment
Why hasn't someone at design spark created such a basic design tool as standard/metric bolt/screw/machine threads and/or gear type/ teeth, as such are used extremely extensively in mechanical design? Sure, toys like tinkercad don't have it either, but that is not saying much.
I am switching from fusion 360 to design spark, and was suprised that such have to be done manually, but that method is extremely inaccurate when trying to create new items that have to match up to factory products, or precisely match existing products to add to a design.
I am just surprised.
Looks like a handy tutorial I'll file away a copy of.
I have to laugh that my first reaction to reading the title was thinking of a Write-Once-Read-Mostly (WORM) drive (an early name for a type of optical storage drive for computers) as opposed to a worm gear drive mechanism. (Though I suppose the latter could be used in the former.) That might actually make a humorous design challenge for a contest closing on April Fools day - design a Write-Once-Read-Mostly drive using only mechanical components designed with DS Mechanical, combined with off-the-shelf electrical / electronic components available from RS or Allied. Include the restriction that the electrical / electronic components must be wireable without soldering. In other words, on the electrical side sticking to building blocks which don't require an extensive electronic design background, keeping the focus on mechanical. A little like a Rube Goldberg design challenge, but without the emphasis on making the design as round-about as possible (no pun intended), other than the restriction on electronics complexity.