Any insights on the working principle of Compression Springs?
 
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Durahl
(@durahl)
Estimable Member
Any insights on the working principle of Compression Springs?

Greetings!

Does anyone have any insights on Compression Springs and their behaviour when choosing between different spring lengths in a same pre tensioned installation length?

I got myself a bunch of Springs of varying Wire Diameter ( 0.4 / 0.6 / 0.8mm ) but identical Rested Length ( 35mm ) and Overall Diameter ( 10mm ) for an RC-Tank Project which had - to put it mildly - VASTLY different holding power in keeping the model afloat while on level ground ( so no variance between the Axles ).

Essentially:

  • the 0.4mm ones acted like they weren't even there ❌
  • the 0.6mm ones appear to be the way to go forward ✅
  • the 0.8 mm ones were strong enough to lift the model with like just 6 springs where 32 were intended to be used ❌

Problems just the 35mm long 0.6mm ones I got are juuuuuust a smidge too weak to keep the Suspension afloat at a 100% total travel distance while already preloaded by 5mm down to 30mm.

A short Video illustrating the design:

And the CAD Model:

With me being this close to the right value using the 0.6mm ones and 0.8 having such a ridiculous off the scale holding power I'm kinda hesitant of even just moving up to 0.7 ( which I can't as the Seller doesn't have them in the proper Overall Diameter ) which brings me to two options going forwards that being:

  • increasing of the preload even further by getting longer Springs in the 40 if not 45mm Rested Length range
  • Packing the Spring Carrier with more than just 2 Springs by weaving two springs together

Any opinions regarding those ideas? ( In any case I'd have to order more Springs ) 🤨
I'd also most likely only be increasing the "strength" of the first to second and seventh to eight Wheel 🤔

Thanks in advance! 😁

Posted : 28/07/2022 10:58 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Any insights on the working principle of Compression Springs?

sorry I have no solution, spring tuning can be achieved in various ways,
spring wire diameter, spring overall diameter and spring pitch, these options seem limited in your application.

You need to watch for the springs becoming 'spring bound' at full compression. there is limited space between the turns of the spring if you use a longer spring with more turns and compress it into the same space, will full compression turn the spring into a wire-wound tube spacer (essentially solid tube)?
interlacing springs may have a similar effect.

In motor engine Valvespring situations, they often use concentric springs to increase tension and d reduce resonance, but I don't think you have space for that.

is there any scope for re shaping the existing springs to a coarser pitch?

regards Joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 29/07/2022 7:46 am
Durahl liked
Durahl
(@durahl)
Estimable Member
Topic starter answered:
RE: Any insights on the working principle of Compression Springs?

Thanks for the reply!

My currently used springs appear to be well out of range from becoming spring bound as using up all of the travel of a Suspension arm will only compress them to about 50% with a considerable amount of air remaining in between the windings - Based on this metric alone I could probably go for twice the length before this would turn into a problem by which time, I assume should have long surpassed the ideal value 😱

As for the concentric spring design... That is actually something I could still make use of as the 10mm Springs I'm using also leave "plenty" of air inside them for such use even with the Retaining Screws and their Brass Sheathing already occupying some of that space 🤔

But over the past days I just realized I could - for starters - just 3D print some Spacers™ to preload the current Springs even more by stacking them in line with the Springs - The sudden inrush of ideas after a few nights of good sleep 🤣

Posted : 01/08/2022 1:05 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Any insights on the working principle of Compression Springs?

many ways to crack a nut. lol

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 01/08/2022 5:49 pm
Richardludwig
(@richardludwig)
Active Member
RE: Any insights on the working principle of Compression Springs?

This is a very sally question but anyone an help me. I want to know about How does a compression spring work? What are four uses of compressed springs in everyday life?

Posted : 04/08/2022 7:54 am
Durahl
(@durahl)
Estimable Member
Topic starter answered:
RE: Any insights on the working principle of Compression Springs?
Posted by: @richardludwig

How does a compression spring work? What are four uses of compressed springs in everyday life?

Well...

...would pretty much be a prime example of how a compression Spring works 😉

For a more in depth explanation on Springs.

Posted : 04/08/2022 5:38 pm
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