Improbability Drive

[Jeremy_BP]

Oh... Well... Um...
My mind is absolutely blown. That is awesome. Would you consider making plans?

 

[steamer]

Hey Ken,

I've used them before in automation applications...so I had an unfair advantage....

Dave

 

[///]

...
For all that harmonic drives are fairly commonplace, few people know what they are or how they work.

I use them all the time in my line of work - robotics.

Cyclo gearboxes are even wierder.

These devices provide reductions between 50-300 : 1 at better than 50% efficiency - which makes them reversible !

Ken

Some of the top-end telescope mounts use harmonic drives instead of the old worm and wheel.
Not heard of cycloidal drive... interesting!

 

[Captain Jerry]

Ken

Your device has been kicking around in the back of my mind, trying to find a slot to fit in. Sort of a radial engine (inside out) and sort of a swash plate (plate angle parallel to shaft) but totally unique. I think you have created a new class of engine. I would call it a "Squash Plate."

Jerry

 

[Ken I]

Jerry, "Squash Plate" :big:

Jeremy_BP - it never crossed my mind that anyone else might want to try it.

I do have drawings - give me a couple of days to tidy it up to "as built" and add a few build notes to it and I'll post it under the downloads section.

Obviously you would have to redesign around whatever bearing you can get your hands on - these things are fearsomely expensive so you would need to find a discard.

This one came out of the "L" or "U" axis drive on a Yaskawa Motoman L10 W 6 robot - which is now hopelessly obsolete - if you can find a local Motoman repair shop they might give you one off an old unit being cannibalised for spares.

The actual part number is
HD (Harmonic Drive Systems) 25-80-474 3
No idea what the designation means - the bore is 28mm and the OD is 60.6 x 62.1 (Eliptical)

Ken

 

[student_Machinist]

:bow: that is unbelievably awesome!

 

[kustomkb]

That's really cool Ken!

It really gets the "wheels" turning, or should I say "harmonic"

 

[Jeremy_BP]

I would absolutely love to build one, although a harmonic drive would be rather difficult to source for me. I'll have to start asking around.

 

[Ken I]

Jeremy_BP - O.K. I've posted the plans under the download section.

I draw anything I make - I'd rather find the obvious flaw on the drawing board than in the middle of manufacturing.

The file contains 2D ACAD *.dwg & *.dxf as well as a *.doc file of build notes.

Ken

 

[ChrisB]

A truly fascinating engine, and an even more fascinating mind to come up with it and build one.

Downloading the plans now, if for nothing else to have a good nose through to work it out. Thanks for taking the time to share this really interesting build with us all. I know that I for one will get a lot out of it.

Cheers


Chris

 

[Jeremy_BP]

Ken - Thanks. Time to start scrounging.

 

[Rocket Man]

That is a very interesting engine.

For many years I have wanted to build the 12 cylinder apposed cylinder engine but I don't have the equipment to make the cam crank shaft. Your engine has given me some ideas to play round with.

 

[bearcar1]

Truly an interesting and unique drive assembly Ken. Fascinating to watch with all of its parts and as has been presented, quite the mystery to figure out how exactly it works. A big thank you for sharing your drawings with us and a well deserved KP for all of your efforts.

BC1
Jim

 

[mu38&Bg#]

I think anyone that's seen a harmonic drive mechanism would remember it. It wasn't obvious in the photos, but I had a hunch that's what was going on. The video proved it, but Steamer had identified it by the I had woken up that day. It's a great idea!

 

[AussieJimG]

Thank you sharing your ingenious engine and for introducing me to the harmonic drive and the cycloidal drive. Now you have got me thinking: does it need a harmonic drive?

Could it be done with the roller bearings on the end of the levers operating on a cam shaped something like the wave generator?

Jim

 

[Ken I]

Jim, you've got a point - if you built an eliptical (4 radius) hub with roller bearings constrained by a cage (which does not have to flex as long as its inner and outer rads don't foul) then each of the levers could contain an arc segment to bear against the rollers.

All horrible and complicated to no usefull purpose other than to have fun.

Ken