Better suspension

5 comments:

E Hines said...

Cool. And like a lot of excellent inventions, amazingly simple and obvious in hindsight.

I wonder if it could be plussed up for automobile wheels.

Be interesting, too, to see if they could be plussed up for aircraft wheels--especially for carrier landings--while not adding to overall undercarriage weight.

Eric Hines

Texan99 said...

It never would have occurred to me to try to put the suspension in the wheel spokes instead of attached to the axle. In fact, I guess I wonder why it works better than way.

E Hines said...

I'm not sure it would work better that way for a mass greater than an occupied wheelchair. That's putting a lot of stress on a hub joint.

It could work well in a wheelchair by putting the volume of a sprung and shocked suspension system inside the wheel, instead of adding that volume onto the chair.

Still, it'd be worth looking into for cars, and if that works out, then maybe for aircraft, too.

Eric Hines

Grim said...

I would guess that the improvement comes from the fact that the shocks can respond faster than if they were centrally located. The impact is a kind of information, which is transmitted along the wheel. Distributing the shocks along the main transmission lines, closer to the source of shocks than the hub, means that there is greater time for the reaction to occur. It's not a lot more time! But our nerves operate on similar timescales, so felt shock might be appreciably lower.

douglas said...

The working models look much better than the CAD models shown at the beginning with their three guide struts and six shock struts- way too heavy. The working model might be light enough- I'm surprised they haven't worked up a composite version yet- but weight is a big consideration, at least for bicycle use. A wheelchair may not go fast enough or it's user put enough miles on it to make much difference, but for a cyclist, having more weight in the rotating portion of the machine means more momentum to overcome, and every acceleration/deceleration requires that much more energy. You usually want the lightest wheels you can get away with. Also, these wheels are doing what spoked wheels have always done, just with more length of compression. On the wheelchair it might make sense to move the suspension to the wheel, as it's really the frame and occupant that are the suspended weight, and therefore lightening that makes sense. On a car, the lighter the suspended components (the wheels and outer, moving suspension bits), the better, so I don't see it happening in cars, unless you count shock absorbing tires which already exist (beyond the suspension effects of regular pneumatic tires, which is considerable). These also have the advantage of not going flat.

The real advantage I see in their design is that the wheel should act like a rigid wheel when forward propulsive energy is applied to it - unlike regular suspensions where you lose a little energy to the compression of the suspension with each pedal stroke/arm push. Theirs only compresses with upward or backward pressures to the wheel. If you back into something though, you'll get no relief from the suspension, but that seems like a more than worthwhile trade off.