# eccentrically cycloidal (EC) gearing



## gor (Nov 25, 2009)

eccentrically cycloidal (EC) gearing:


*http://ec-gearing.ru/index.php?lg=en*

*Several times (~5) reduction of weight and overall dimensions*;
*Increased gear ratio* U in one stage up to 30
(in the involute gearing U<= 8);
*Allowed to increase misalignment and center-to-center clearance in the EC gearing 5-10 times* compared with functioning standard parameters for the involute gearing without loss of force characteristics in the enegagement;
*Efficiency* in the EC gearing approaches the rolling efficiency 99,9% for Кfr = 0.075, *since the meshing point is in the pitch point*.
Cost of production EC-gears several times lower than common involute gears and requires only universal equipment and universal tools (end-mills). 

http://www.ec-gearing.com/video.php


_applyed: _
http://ec-gearing.ru/fotos.php


p.s. if all brilliant - simple, EC can be effective as AK47 : )))

...some sutes tried to figure-out how it work


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## gor (Nov 25, 2009)

could be not bad for reduction from 24000rpm 400Hz equipment







http://www.diyelectriccar.com/forums/showthread.php?p=266824#post266824


or from 20 000; 60 000; 90 000 rpm turbos

Output: 75 KVA (60 Kw)
APU Engine : *27.7* kg
*Reduction Gear:45.4 kg
*Generator:*41 *kg
GCU:4.5 kg
Auxiliary : 118.6 kg


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## dtbaker (Jan 5, 2008)

very interesting stuff... my first job was engineering a 'gearless transmission' based on epi and hypo trochoidal forms with rollers between mounted on an eccentric. prototypes worked, but the tolerances needed for full speed and full torque were INTENSE (+/- 10 millionths of an inch!). The fit and concentricity of the housing and bearing surface pieces had to be PERFECT to work. production never happened because we did not succeed in building production grinders that could cut the forms accurately enough in a short enough time to be cost effective, and inspection of the parts was really really difficult to tell whether or not the form produced was within tolerance to theorectical. The slightest error in the forms started galling and pits in the surfaces and they self-destructed rapidly.....

but interesting.


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## gor (Nov 25, 2009)

dtbaker said:


> very interesting stuff... my first job was engineering a 'gearless transmission' based on epi and hypo trochoidal forms with rollers between mounted on an eccentric. prototypes worked, but the tolerances needed for full speed and full torque were INTENSE (+/- 10 millionths of an inch!). The fit and concentricity of the housing and bearing surface pieces had to be PERFECT to work. production never happened because we did not succeed in building production grinders that could cut the forms accurately enough in a short enough time to be cost effective, and inspection of the parts was really really difficult to tell whether or not the form produced was within tolerance to theorectical. The slightest error in the forms started galling and pits in the surfaces and they self-destructed rapidly.....
> 
> but interesting.


is there similar tolerances problem on latest cars with CVTs? (where special oil in contact patch between metal pulley and metal belt acts like hard (solid) substance and resist slipping) 

speaking of EC - they said it can be made on regular equipment, tolerances - more forgiving... 
... and our DIY guys have tools and know how to use it ... : )))


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## unclematt (May 11, 2008)

I love the gearing concept, but the site caused my virus protection software to have a melt down, and even my ISP emailed about a threat from the site. Now windows doean't want to let me navigate to that URL any more. Anyone else run into this?


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## Guest (Nov 3, 2011)

unclematt said:


> I love the gearing concept, but the site caused my virus protection software to have a melt down, and even my ISP emailed about a threat from the site. Now windows doean't want to let me navigate to that URL any more. Anyone else run into this?


Not on this end. But then again I am running a Mac. Interesting gears and their uses. I like the torque multiplier.


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## unclematt (May 11, 2008)

What I need to see on these types of gears is their dynamic loading limits. Their pdf info pages are all in russian though...

Anyone have any data on this?


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## dtbaker (Jan 5, 2008)

unclematt said:


> What I need to see on these types of gears is their dynamic loading limits. Their pdf info pages are all in russian though...
> 
> Anyone have any data on this?


the shock loading capacity far exceeds normal 'toothed' gears because there are 80% or so of the 'lobes' in rolling contact at any time.... involute gear teeth have less than 3 'teeth' bearing the load at any given time.

thats the theory anyway. thats also what makes them hard to manufacture; the forms have to be perfect to allow all those contact points, avoid binding, and avoid 'slipping' the balls or rollers that are between the trochoidal rings.


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## unclematt (May 11, 2008)

I understand their benefits, I just need to find the actual data on their ability to withstand dynamic loads, if indeed there is any such data available online. Guess I will have to write them and ask. I also need to find out if they have an internal ring gear/pinion version as well.


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## unclematt (May 11, 2008)

Well, I wrote them for more details about their gearing, and they responded in Russian...


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## PhantomPholly (Aug 20, 2008)

Interesting variation on a theme - I once saw a transmission based on a ratcheting mechanism that worked and gave nearly infinite variable ratios, but like so many ideas the devil is in the details.

CVTs are getting dirt simple, cheap, and efficient. Unless this technology fundamentally offers something better and cheaper it will never get into mass production. "Perfect" is all too often the enemy of "good enough."


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## unclematt (May 11, 2008)

PhantomPholly said:


> Interesting variation on a theme - I once saw a transmission based on a ratcheting mechanism that worked and gave nearly infinite variable ratios, but like so many ideas the devil is in the details.
> 
> CVTs are getting dirt simple, cheap, and efficient. Unless this technology fundamentally offers something better and cheaper it will never get into mass production. "Perfect" is all too often the enemy of "good enough."


 You might read a little more on this. The sensitivity of these specific gears to variations in center-to-center distance is much less than involute gearing. Also much less sophisticated manufacturing equipment is need to create these gears. In fact they allow you to be less "perfect" than with involute gearing when it comes to application and manufacturing, and subsequently claim to offer a better, cheaper, stronger gear techonology...


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## dtbaker (Jan 5, 2008)

unclematt said:


> You might read a little more on this. The sensitivity of these specific gears to variations in center-to-center distance is much less than involute gearing. Also much less sophisticated manufacturing equipment is need to create these gears. In fact they allow you to be less "perfect" than with involute gearing when it comes to application and manufacturing, and subsequently claim to offer a better, cheaper, stronger gear techonology...



these may be the claims....

but quite frankly I don't see HOW their proposed system would be less sensitive to surface irregularity or concentricity. Any time you start a stack of concentric bearing surfaces, and then throw an eccentric and non-round, non-flat shapes (trochoidal) you are talking high-precesion, high-tech, and very challenging manufacturing.


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## unclematt (May 11, 2008)

dtbaker said:


> these may be the claims....
> 
> but quite frankly I don't see HOW their proposed system would be less sensitive to surface irregularity or concentricity. Any time you start a stack of concentric bearing surfaces, and then throw an eccentric and non-round, non-flat shapes (trochoidal) you are talking high-precesion, high-tech, and very challenging manufacturing.


I didn't say anything about surface irregularity, where did that come from? I just find this gear form interesting and will use it in my designs if claims turn out to be true.

When I emailed them, they responded in Russian, which I translated online. They wouldn't even tell me if they had an internal ring gear design or not without me disclosing what I wanted to use it for. Not a good way to build confidence in your brand new gear design!


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## dtbaker (Jan 5, 2008)

unclematt said:


> I didn't say anything about surface irregularity, where did that come from?



any time you have a 'toothed' shape to manufacture in high production, you end up either indexing and finishing each tooth one at a time, or going with really slow jig grinding. 

Regardless, with high-load bearing surfaces, the final steps after heat-treat pretty much have to be grinding, and then lapping to get final finish... Grinding trochoidal shapes is NOT easy, hard to inspect afterward, and the problem that I know we had was the slightest error would leave a microscopic 'step' or irregularity between lobes, which causes the balls or rollers between the trochoidal shapes to start bouncing or skidding, surfaces spall, and the unit fails.... believe me, I've seen a 3 HP transmission develop harmonic vibrations under load bad enough to lift a 900 pound concrete table off the floor when the bearing surfaces start disintegrating and they are being flung around on an eccentric at 3600 rpm.


you can believe what you want, I'm just trying to tell you to be careful because what I know about similar designs make their claims highly unlikely.


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## unclematt (May 11, 2008)

dtbaker said:


> these may be the claims....
> 
> but quite frankly I don't see HOW their proposed system would be less sensitive to surface irregularity or concentricity. Any time you start a stack of concentric bearing surfaces, and then throw an eccentric and non-round, non-flat shapes (trochoidal) you are talking high-precesion, high-tech, and very challenging manufacturing.


Yes, that is what they are claiming. And until we have evidence that their claims are fraudulent, I won't be operating as if they were. Assuming things like that is a short trip to failure when looking for design alternatives to involute gear forms, or pretty much any endeavor. Yes, they need to prove their claims. No, I won't be making assumptions one way or the other until such evidence has been presented and I have reviewed it. Thus my attempt to contact them...

This is much like the circular arc gear forms that China likes to use, but the rest of the world likes to ignore. When I post info about circular-arc gears at engineering sites most of the engineers posting at those sites reject it outright because they are unfamiliar with the design. That's not the way I operate, and I don't know anyone successful who emulates that approach to research.


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## dtbaker (Jan 5, 2008)

unclematt said:


> Yes, that is what they are claiming. And until we have evidence that their claims are fraudulent, I won't be operating as if they were. Assuming things like that is a short trip to failure when looking for design alternatives to involute gear forms,


All I am saying is 'good luck'. I spent 4 years on a design team trying to get 5hp tramsmissions using trochoidal forms from prototype (where we could jig-grind and hand fit) to production using a multimillion dollar higher-speed indexing grinders... and failed.

It IS a very cool idea, and had some very interesting benefits, but will be VERY challenging to produce in production at low cost.


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## Salty9 (Jul 13, 2009)

Gears = Mechanical Porn. Guaranteed to corrupt the unsophisticated.


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