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Parametric airless tire

by tjhowse, published

Parametric airless tire by tjhowse Feb 13, 2012

Description

This design is inspired by Bridgestone's airless tire concept:

physorg.com/news/2011-12-bridgestone-airless-concept-tokyo.html

Using the natural springiness of plastic, this design can absorb shock and vibration in a manner similar to a pneumatic tire, but cannot be punctured.

Videos here:
youtube.com/watch?v=3LctFwZhY1M
youtube.com/watch?v=sXBgaaI7dHY

This design is fully parametric.

Update: Added tiny (0.001) offset between spirals. Openscad errored when trying to export an STL otherwise.

Recent Comments

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TETRIX, We use ROBOTC or Labview to program LEGO Mindstorm controllers to interface with TETRIX electronics and parts.

Is this for Vex?

With a grip_depth of 1, and a grip_density of 0.5, 50% of the outer circumference of the wheel will be raised, and 50% will be lowered.

Make sure you're rendering the model in openscad before the export. Do this by pressing F6. Also make sure you're using the latest version of openscad.

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License

GNU - GPL
Parametric airless tire by tjhowse is licensed under the GNU - GPL license.

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag. Print Thing Tag

Instructions

Tweak values to suit your application, compile, slice and print! If you're having traction problems, I suggest a zig-zag of hot glue around the circumference to give it a more frictious surface.

Comments

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nyl0cke on Aug 25, 2013 said:

does any one have any experience with printing Polycarb? Is it similar to PLA but stronger, or more similar to ABS? I would like to try using this as a replacement wheel for a Robotics competition, but I dont want to use PLA because it would probably break if another robot accidentally hit our bot. I know I could get good results with Nylon if there were enough "spokes" i guess you could call them, but I would like to know more about the properties of printing Polycarb.

harrio34 on Feb 16, 2014 said:

Is this for Vex?

Gigahurtz on Aug 14, 2013 said:

Thanks for posting this! I'm trying to use the SCAD file in OpenSCAD, but am having some trouble rendering with the grips setting. I'd like grips to have a 50% density along the outer wheel. Do I need to enter a fractional amount (e.g. 0.5)? Also, what does grip_depth mean? I'm also having trouble exporting a .stl file for printing. It exports, but when I open the .stl file, it is empty.

tjhowse on Nov 3, 2013 said:

With a grip_depth of 1, and a grip_density of 0.5, 50% of the outer circumference of the wheel will be raised, and 50% will be lowered.

Make sure you're rendering the model in openscad before the export. Do this by pressing F6. Also make sure you're using the latest version of openscad.

TeamTeamUSA on Mar 14, 2012 said:

Nice! :)

Ron Arad made a bicycle with spring-steel tires based upon a similar concept:

http://www.core77.com/blog/mat...

qirien on Mar 12, 2012 said:

Cool! It would be neat to make one that could interface with LEGO axles . . .

sesam on Mar 4, 2012 said:

Any guess if this design is strong enough to replace a 32cm (12-13inch) wheel for a light-weight (aluminium) wheelbarrow? (Pumping the tire every time before use tiring :-P)

nyl0cke on Aug 25, 2013 said:

If you make it out of Nylon and have enough "spokes" I wouldn't doubt it

tlalexander on Feb 22, 2012 said:

Neat! I played with this a while back but mine was too stiff and I never tried again. How does this work?

Also, I designed mine just like yours, but later noticed that the tweel and others have spirals that go both ways. Prevents deformation both front and back.

tlalexander on Feb 22, 2012 said:

Oops, and then I read the other comments.

ionraice on Feb 15, 2012 said:

This is called a tweel for posterity.

laird on Feb 13, 2012 said:

Very cool!

Have you made a double spiral like Bridgestone's airless tire? A small change to the code but not printed yet:

for (i = [0:spoke_count-1])
{
rotate([0,0,i * (360/spoke_count)]) translate([(spoke_dia/2)-(dia_in/2)-hub_thickness,0,0]) spoke();
rotate([0,180,i * (360/spoke_count)]) translate([
(spoke_dia/2)-(dia_in/2)-hub_thickness,0,-height]) spoke();
}

Probably much less soft.

tjhowse on Feb 14, 2012 said:

I think the reason they have two counter-rotating spirals is such that the characteristics of the wheel don't change too much under torque. If the hub is accelerated quickly it tends to twist independently of the rim, splaying or twisting the spokes, changing the spring constant. Stiffness isn't an issue with my design, since you can add spokes or make them thicker until you reach the desired stiffness.

I added a "double_spiral" boolean so people can generate counter-rotating spiral wheels if they want.

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