GearHeads Corner

General Category => Suggestions for Future => Topic started by: Dan on October 28, 2011, 10:54:29 AM



Title: Hypocycloid Gear
Post by: Dan on October 28, 2011, 10:54:29 AM
Hi Art,

Can you consider adding these? Appears to be lots of informati on on these and even the math involved. See this link:

http://www.zincland.com/hypocycloid

Dan


Title: Re: Hypocycloid Gear
Post by: ArtF on October 28, 2011, 11:16:19 AM
Dan:

 I think thats pretty muc a internal cage gear as shown here..

Art


Title: Re: Hypocycloid Gear
Post by: Dan on October 28, 2011, 11:58:07 AM
Ah.. interesti ng, Art, I haven't thought about this. It's pretty close. But the transitio n between the valley and lobe is not smooth and increasin g the pins diameter makes things worse and at some point Gearotic can't handle it.

Dan


Title: Re: Hypocycloid Gear
Post by: ArtF on October 28, 2011, 12:10:25 PM
Dan:

  Actually, it should be identical .. I think this is a bug and it has been added to my bug list. That pin hole
should translate smoothly to the outside hypocycli c curve. Early code, so I hadnt noticed the error. I think when fix it would do as you describe in that thread..

Art


Title: Re: Hypocycloid Gear
Post by: Dan on October 28, 2011, 12:20:42 PM
Art,

Thanks for that. Would be interesti ng playing with it. Please let know when it's fixed.

Dan


Title: Re: Hypocycloid Gear
Post by: BobL on October 28, 2011, 05:16:08 PM
Dan;

 That particula r gear reduction method would make an awesome reduction mechanism for a clock !!!!

Thanks for posting

Cheers
Bob ;)


Title: Re: Hypocycloid Gear
Post by: Mooselake on October 29, 2011, 12:55:56 AM
I was thinking that, too.  How much drag would it have?

Kirk


Title: Re: Hypocycloid Gear
Post by: Dan on October 29, 2011, 01:00:50 AM
Yes, Bob, it would. They are very compact and theoretic ally you don't have a limit on a single stage transmiss ion ratio.

Kirk, these drives are very efficient . Single stage efficienc y in access of 90%.

Dan


Title: Re: Hypocycloid Gear
Post by: Mooselake on October 29, 2011, 09:48:43 PM
Way back when I cut a lantern and pinion gearset, with 1/8" pins, that ended up with very pointy teeth that had problems with binding even after a lot of fine sanding.  At the time I assumed it was a problem on my part, but never got back to it.  I'll try to make it again after the changes.

Art, would it be hard to be able to vary the cage size while you're in there?  The pin holes left gaps in the outside edge where the pins were flush with the edge.  With the little dowels I had to remake it several times because it kept breaking when inserting the pins, probably my hand-eye coordinat ion problem.  IIRC correctly I finally had to soak the pieces in superglue to strengthe n them.  It would be pretty handy to be able to add a little extra beef on the outside of the pin holes for those of us approachi ng mature citizen status.

Did I read the reference d article right?  A 60 tooth pinion and a 59 tooth lantern would give 60:1 in one shot?  My 56 tooth 1/8" pin pinion is just a bit over 3" across, so 60 would be pretty easy with my mini router.  The result would certainly make an unusual clock.

Kirk


Title: Re: Hypocycloid Gear
Post by: Dan on October 30, 2011, 12:30:53 AM
Hi Kirk,

Hope a fix will come soon.

Did I read the reference d article right?  A 60 tooth pinion and a 59 tooth lantern would give 60:1 in one shot?  My 56 tooth 1/8" pin pinion is just a bit over 3" across, so 60 would be pretty easy with my mini router.  The result would certainly make an unusual clock.

Yes, that's true! 60:1 in one stage!

Dan


Title: Re: Hypocycloid Gear
Post by: Mooselake on October 30, 2011, 10:37:10 AM
Me, too.  More amazing things from GM!

Seems like just yesterday CNC took multi-million dollar mainframe s, APT post-processors, and big buck milling machines (had a summer job around 1970 where a couple coworkers worked on those post processor s while I wrote a large fortran program that cranked out giant (non-cnc) cobol programs); now I have one in the basement.

Art, how did you make that picture?  Every combinati on of DP and pin size I tried still ended up with pointy gears.

Kirk


Title: Re: Hypocycloid Gear
Post by: ArtF on October 30, 2011, 12:11:13 PM
Kirk:

  Latest version fixes the errors in it, but that photo was from the last version. You get those rounded teeth, ( which are epicycloi ds mixed with hypocyclo idals )
by selecting the cage gear as an planetary gear..jus t make the cage have more pins than the spur and the internal selection will light up for selection .

Art


Title: Re: Hypocycloid Gear
Post by: ArtF on October 30, 2011, 12:15:11 PM
Hi Guys:

  Just a note.. unless Im missing something, I think the ratio you were seeing was more like 60:59 , not 60:1..
Harmonic drives, ( which I think that is..), reduce very little, very efficient, but very small reduction unless the
pin number is 60 times the spur gear tooth count. When you see the two gears beign similar size, thats a very
low reduction of about 60:59 ( assuming there is 60 tooth pin, and 59 tooth spur)..

   Hmm, I wonder how a successsi on of gears inside one another each reducing a few % woudl look.. :) )

Art


Title: Re: Hypocycloid Gear
Post by: ArtF on October 30, 2011, 12:17:52 PM
Ahh, I take that back..dri ll test makes it pretty clear.. The eccentric shaft fooled me a bit.. Does look like a pretty good method o
reduction, very smooth too.. make a great clock Id think..

ARt


Title: Re: Hypocycloid Gear
Post by: Dan on October 30, 2011, 12:31:53 PM
Hi Art,

Yes, a very neat drive system. I wonder who invented it. Pretty clever.

I downloade d the latest version it looks better now and I can't see nay interfere nce any more, but the transitio ns are still too distinct I think. Especiall y when the pin diameter is bigger than the module.

The attached screen shot is of module 3 and 5mm pin diameter. I don't know if the sharp transitio n is bad or no (simulatio n look good) but common sense tells me that smoother is better.

Dan


Title: Re: Hypocycloid Gear
Post by: ArtF on October 30, 2011, 12:58:58 PM
Dan:

   I suspect this is the differenc e between theory and practice in math. There is no roughness in terms of the gear since simulatio n shows it never conflicts with the pins. ( You cant get smoother than no conflict. .)
BUT, in practice leaving some backlash, and removing material that really isnt required can make an exact model of the gear look different . Take for example the case of non-internals.. the sharp tips are not really required, BUT they do allow teeth furhter away to also have some holding power.. so the perfect implement ation of the model dictates the sharp teeth, but a practical implement ation wouldl clip the teeth
to a maximum diameter and perhaps allow some backlash. The gear woudl look different as a result.
  All of my models I try to put in as perfect math models, thinking they could then be modified in one way or another as Im shown the limiation s of the theoretic al model vs the real world applicati on.
   As to the speed reducer, its a very similar tooth shape, BUT changed as a result dictated by the desired end result. That reducer is a kinda differenc e engine as I see it so far.... As I said earlier, the ratio is actually 60:59 or so in the concept of using such a gear, but the next two levels of it are calculati ng the differenc e in ratios and turning the output shaft at that rate, ( hence a 60:1 reduction ). ( Im making up the ratios, just wanted to show the ratio changes they are producein g). 

  Im still analysing that gear though, so I may "change my mind". It IS a facinatin g way to get a large scale reduction with very little friction. .
Mayeb we need a way to make such things.. lol


Title: Re: Hypocycloid Gear
Post by: Dan on October 30, 2011, 01:04:52 PM
Art,

Thanks for the explanati on. I will try to output some Gcode and machine those and see if they work as a speed reducer. Will post the results.

Dan


Title: Re: Hypocycloid Gear
Post by: John S on October 30, 2011, 01:28:36 PM
Andy Payne from Cambam had two of these on his stand at Harrogate show this year.
One was a 10:1 reduction and the other was 100:1 consistin g of two 10:1 stages.
Cut in acrylic they worked very well.

Andy has done a plug in for Cambam to generate these hypercycl oids.


Title: Re: Hypocycloid Gear
Post by: Mooselake on October 30, 2011, 01:30:55 PM
Thanks, I missed that.

Kirk

Kirk:

You get those rounded teeth, ( which are epicycloi ds mixed with hypocyclo idals )
y selecting the cage gear as an planetary gear..jus t make the cage have more pins than the spur and the internal selection will light up for selection .

Art



Title: Re: Hypocycloid Gear
Post by: Mooselake on October 30, 2011, 02:32:19 PM
Is the gear center distance how much the cage shaft has to be offset?  For 59 0.125" pins, 60 teeth, and a 15.0 DP it gets -0.0333 inches, which seems pretty small - I was expecting about half a pin or .06someth ing.

While John Sullivan could whip one off in about 15 seconds, I've never made an eccentric shaft.  I've got some 3/8" aluminum rod and a new/unused 4 jaw chuck for the 7x10 minilathe .  Is the correct procedure to offset the jaws by 33 thousandt hs (or whatever) and turning a 1/4" shaft on the end?

Kirk


Title: Re: Hypocycloid Gear
Post by: ArtF on October 30, 2011, 02:44:25 PM
Kirk:

   Offset shaft distance is actually simple the differenc e between pitch diamters of that
DP of a gear. If it was allowed for the two gears to be the same diameter or number of teeth,
there woudl be no offset. SO you cant relate it to the pin size at all, change pin and the shaft offset stays the same..

Art


Title: Re: Hypocycloid Gear
Post by: ArtF on October 30, 2011, 08:14:02 PM
John:

  Might have to try my hand at that as well on the laser to see how well they roll.
I checked CamBam's cycloidic s.. their made different ly from mine, you can see it the way the pin sets,
but mine follow the pin more accuratel y at the cycloidic inflectio n point , so the pin sits completel y in the recess,
where CamBams has the pins sitting with only one point touching. . Neither is wrong I think, but Im curious about the
efficienc y of the two methods in practice. .

Art


Title: Re: Hypocycloid Gear
Post by: Dan on October 31, 2011, 01:37:03 PM
Made a quick prototype to prove the concept. Made a two stage 60:1 reducer out of acrylic. The result is very good. Movement is very smooth. Backlash is evident, but then I intention ally put in large clearance s (0.1-0.2mm). Reducing clearance s backlash should theoretic ally approach zero since there are at least 2 teeth engaged from opposite sides at any given instance.

Dan


Title: Re: Hypocycloid Gear
Post by: Dan on October 31, 2011, 01:38:31 PM
And two more:



Title: Re: Hypocycloid Gear
Post by: Dan on October 31, 2011, 02:46:17 PM
Apparentl y my reduction ratio math is wrong. The reduction in two stages with this reducer doesn't work as I thought it did. My first input pin ring has 11 pins, then there is the 10 lobe disk. This should give 10:1 reduction and is obvious. Then there is the second cam disk with 6 lobes which meshes with the 7 pin output ring. I had thought this would give another 6:1 reduction . However, counting the number of revolutio ns I am getting 17.5:1 ratio. I can't explain it and figure the right formula for reduction ratio calculati on yet.  ???

Dan


Title: Re: Hypocycloid Gear
Post by: ArtF on October 31, 2011, 03:18:40 PM
Dan:

  Hmm, math seems right. I dont see any informati on on the multiplic ation of ratio's in such a unit though... .

I see now why my cycloids are different looking.. their correct, but there is an optimiisa tion of the pressure angle that can be done..
Im looking into it to see if it should be added. Whats there will work, but they claim the circling of the pins bottom when its in the
groove is wated and can create binding.. they reduce by an optimisat ion method..

 That looks pretty good what you have though.. must be somethign simple about the math we're missing.. I cant see 17:5 as a
magic number that points out what the math is top of head..

Art


Title: Re: Hypocycloid Gear
Post by: Dan on October 31, 2011, 03:56:10 PM
Art,

Yes, I don't know where the 17.5:1 does come from either. Regarding the multiplic ation of ratios, I haven't found any info on this either, except for the link I posted in the first message in this thread (www.zincl and.com/hypocycloid). In his video it does look like a 100:1.

Please let me know if you shall find an explanati on.

Regarding the optimizat ion, I think that the sharp transitio n corners will be crushed by extensive operation under load. And this might be more so if you try to keep things tight to minimize backlash.

Dan


Title: Re: Hypocycloid Gear
Post by: ArtF on October 31, 2011, 03:59:47 PM
Dan:

 Its possible, though it shouldnt. .Id think the forces involved are being tranmisst ed over a much larger area when your in the inflectio n point.. Im no expert though..

  Ill dwell on the 17.5:1 ..

Art


Title: Re: Hypocycloid Gear
Post by: Dan on November 01, 2011, 01:16:02 AM
Art,

Found the answer:
http://forums.reprap.org/read.php?14,35968,71742#msg-71742

I will retype the formula he derived below in a more convenien t way:

I/O = (b+1) / (b-a) , where,

I - input speed
O - output speed
a - first (or input) stage ratio
b - second (or output) stage ratio

Substitut ing the numbers for my example:

I/O = (1/6 + 1) / (1/6 - 1/10) = 17.5

Makes sense... doesn't it ;D

Dan



Title: Re: Hypocycloid Gear
Post by: ArtF on November 01, 2011, 07:27:39 AM
Dan:

 Perfect sense.. Thx for the update. Ill ask Bob to add this to a reference topic

Art


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 22, 2011, 06:21:18 PM
If we want to reduce back lash why not design the pins to have bearings on them this should reduce friction as well.

Got to say love the programs ability to pull this one off, have wanted to use these type of reduction gearboxs in a heap of factory projects so now I can.

Tony


Title: Re: Hypocycloid Gear
Post by: Dan on December 23, 2011, 01:28:34 AM
Tony,

There is no friction (not dynamic anyway) as the pins have a rolling movement against the cams.

Dan


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 23, 2011, 02:20:52 PM
Hi Dan,
On some of the simulatio ns they have bushs on the pins so thats why I figure there nust be friction.  See this video http://www.youtube.com/watch?v=YRATbJs6zac&feature=related
That said there are plenty of units in the real world that done have bushes so I thick you must be right.

Also what happens with formula when both ratios are the same arn't you then dividing by "Zero" which doesn't work.  See the video of the design with the same ratio.
http://www.youtube.com/watch?v=aDifch4iV48

Tony




Title: Re: Hypocycloid Gear
Post by: Dan on December 24, 2011, 01:24:12 AM
Tony,

You know what, I played a bit with the one I made and watched the teeth and I am pretty certain there IS friction. Don't know why the claim there isn't. It did look that way at first, but know I am convinced in the opposite.

Interesti ng point about the ratio. I have no answer for that.

Dan


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 24, 2011, 06:06:56 AM
HI Dan,
I am glad I didn't turn out to be a fool, I though I might have got the formula wrong.   I have been following a tread about 4th axis back lash over here  http://www.cnczone.com/forums/linear_rotary_motion/72261-backlash_free_rotary_table.html
  and there has been some discusion about this type of drives right back at the start because they have miniual backlash.  When I found this thread with this soft ware my brain got excited.

A question if you preload a gear in the same way they do with engines would it increase energy to drive the unit.
Tony


Title: Re: Hypocycloid Gear
Post by: Dan on December 24, 2011, 09:16:43 AM
Hi tony,

Yes. I have seen that thread.

Can you explain your question?

Dan


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 24, 2011, 03:35:48 PM
Sorry Dan my brain tends to work on a different planet to most people and as such I forget to explain myself correctly .

The cam shaft drive on a Subaru engine has a timing belt to drive the inlet cam shaft but there is a gear from that camshaft to the exhaust camshaft.  To get rid of bacl lash the gear on the exhaust is cut in half and spring loaded to stop any backlash.

In that thread they talked about doing this to reduce backlash but they say it will increase load on the drive due to the motor needing to fight against the spring.  I am of the opinion that its a zero or close to increase in load.
My logic is what extra energy required to move in 1 direction is compensat ed by the spring wantingn to push it along.  In simple terms by the nature of the spring load the gears want to push apart so if I drive either direction 1 of the two springloa ded gears will naturally go in the direction I want to go.  This then by fact means the load has come off the other.
Therefor no dead load as everyone has claimed.
The assumptio n here is that the spring loaded gear cannot be the driver gear.

Sorry for the long winded post but I hope I explained myself corrcetly this time.
Tony


Title: Re: Hypocycloid Gear
Post by: Dan on December 25, 2011, 10:37:10 AM
Hi Tony,

You are describin g a sort of a perpetuum mobile ;-)

If you look at it closer you will see that by putting a spring tough enough to maintain zero backlash under load, you're actually increasin g the load on the gears and essential ly the energy required to move them. There will always be friction from BOTH sides of a tooth.

Dan


Title: Re: Hypocycloid Gear
Post by: danmauch on December 25, 2011, 11:27:37 AM
 That technique of splitting a gear and installin g a spring has been around for years. A long time ago an a place far, far away I use to be an  Submarine Ordnance machinist . One of my jobs  was to install the Torpedo Data Computer (TDC) . These were the old WW2 mechanica l computere rs that used selsen motors driving gear trains to solve the Gyro angle for firing the torpedoes . I use to marvel at the the minature antibackl ash gearing that used the internal springs to eleminate the backlash.
Dan

Sorry Dan my brain tends to work on a different planet to most people and as such I forget to explain myself correctly .

The cam shaft drive on a Subaru engine has a timing belt to drive the inlet cam shaft but there is a gear from that camshaft to the exhaust camshaft.  To get rid of bacl lash the gear on the exhaust is cut in half and spring loaded to stop any backlash.

In that thread they talked about doing this to reduce backlash but they say it will increase load on the drive due to the motor needing to fight against the spring.  I am of the opinion that its a zero or close to increase in load.
My logic is what extra energy required to move in 1 direction is compensat ed by the spring wantingn to push it along.  In simple terms by the nature of the spring load the gears want to push apart so if I drive either direction 1 of the two springloa ded gears will naturally go in the direction I want to go.  This then by fact means the load has come off the other.
Therefor no dead load as everyone has claimed.
The assumptio n here is that the spring loaded gear cannot be the driver gear.

Sorry for the long winded post but I hope I explained myself corrcetly this time.
Tony


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 25, 2011, 01:01:18 PM
On thinking about the Hypocyclo id gear,
Some weird part of my brain tells me it should be,
add the ratios for each stage eg 6 + 10 is 16 plus 1 (because the second stage arangemen t doesn't cause the loss of 1 on both stage) and add a half due to the two stage, (being 1 divided by 2)
Net answer is 17.5.  Don't ask me how I know it right it just is (I think).

The reason you can't find much about this design is that I beleive it binds up and I couldn't not find any aviable commerica lly.  Plenty of CAD simulatio ns such as the one that was linked to but if you remember it had high friction according the CAD program.  I searched the net and every comerical ly aviable drive I found had the 2 centre drives moving indipende nt of each other.  For my 2 bobs worth the proper gear ratio is held back by the two centre plates being attached together.

All of what I have said above could be wrong and I am open to being corrected, its just my brain with crazy logic.
http://www.youtube.com/watch?v=_3OwTd0GG78
http://www.youtube.com/watch?v=oEgnOS4Y4zU

Have a great day all.
Tony


Title: Re: Hypocycloid Gear
Post by: Dan on December 25, 2011, 01:27:17 PM
Funny they never mention the main advantage that we ascribe to hypocyclo ids - zero backlash. I am certain that they wouldn't miss such an advantage . But I still believe that the backlash is very minimal since there are always several teeth in contact from both sides and if machined to close tolerance backlash should be close to practical zero.

Dan


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 27, 2011, 08:54:41 PM
I did a bit of research and the Cyclo reduction s are around 1 to 3 Arcmin of free play for high reduction s.  The best on plantery at single reduction 10:1 sort of thing and 3 to 5 and the best double reduction at 25:1 double reduction at 5 to 7 arcmin.  My guess is if you wanted to get a plantery out to 100:1 were the cyclo drives are you would end up with a crazy backlast of 15plus arcmin.   When you dig the only way to go is Cyclo drives if you are chasing minual backlash.

If I understan d it correctly there are 21,600 acrminute s in a full 360 I think I can lives with a error of 5.  On the flip side if you could build your own Hypocyclo id drive you wouldn't need it to be perfect and you would still get minual backlash.
Tony


Title: Re: Hypocycloid Gear
Post by: Dan on December 28, 2011, 03:46:35 AM
Tony,

I too have come to an understan ding why they say it's pure rolling movement. If you allow some clearance between the cams and pins then it's true. But if you have too tight a fit (probably not practical) then the (so to say) trailing edge of the cam would rub against the disengagi ng pin.

And just to add to what you said: 5 arcminute s will translate to 0.07mm at the circumfer ence of a 100mm workpiece .

Dan


Title: Re: Hypocycloid Gear
Post by: DesertRunner on December 29, 2011, 01:10:57 AM
And just to add to what you said: 5 arcminute s will translate to 0.07mm at the circumfer ence of a 100mm workpiece

Most Z axis would not be that accurate, now I see it in a number I will move on from worrying about backlash on the 4th axis as its not the issue people make out.  How ever I am still intereste d in simple Hypocyclo id drives for some of my packing robots etc at work.

Dan you didn't comment on the fact that I don't think you can have the two reduction s configure the way you and others are doing on the sample you built.  Did you find any  real world commerica l units designed that way.  The reason I ask is that if it is possible it would be easier.

Dan Mauch I keep thinking about your comment, I am guessing but the power the gears took to drive must have been critical so even though they were springed the friction must not have increased that much.
Tony


Title: Re: Hypocycloid Gear
Post by: Dan on December 29, 2011, 04:07:54 AM
Yes, 0.07mm may not be a lot, but it mostly depends on what you're doing. If it's a precision gear then it may be too much.

Dan you didn't comment on the fact that I don't think you can have the two reduction s configure the way you and others are doing on the sample you built.  Did you find any  real world commerica l units designed that way.  The reason I ask is that if it is possible it would be easier.

I can have the reduction s that way merely because I tried it and it worked ;)

I haven't seen any commercia l ones done that way either, but then they don't usually advertise what's in there. I believe that it's mostly due to the complex ratio formula that they aren't popular. It's hard to get round numbers and a logical sequence of ratio steps. Then there is also that guy's (from the other forum I linked to) comment on these drives, which also makes some sense about efficienc y. The head hurts trying to analyze this. A single stage or a true double stage hypocyclo id reduction is far better understan dable.

Dan


Title: Re: Hypocycloid Gear
Post by: dhugger on January 26, 2014, 08:45:16 AM
A couple years back, an interest in hypocyclo id gears began growing in me, particula rly the idea of using a dual stage design. I couldn't find munch informati on online in terms of the math behind them. Everythin g I found seemed to require a very specific set of parameter s. And, I wanted to build a clock with hypocyclo id rescuers, so I began experimen ting with and developin g the mechanism s on my own. I eventuall y came up with a set of equation that worked and used them to wrote a Python script to generate the parameter s for dual stage reducers. That script is here: http://www.derekhugger.com/tools/dsHypoGen.zip

The clock I made that takes advantage of this reduction method is here: http://www.derekhugger.com/riven.html

-Derek


Title: Re: Hypocycloid Gear
Post by: ArtF on January 26, 2014, 10:19:43 AM
Derek:

   That is one excellent piece of timekeepe r.  I bow in your general direction .
Hypo's are one the modules I need to get to in GT. Ive been slow because I think it
deserves a fair amount of attention and options, much more so than GM had.
Yours is an inspiring piece, Ill give it much more thought now that I know what
I need to compete against.. :)

Thx for the informati on..

Art


Title: Re: Hypocycloid Gear
Post by: danmauch on January 26, 2014, 11:49:06 AM
Really nice work. You probably could have saved yourself some time if you used CamBam. There is a hypercycl oid plugin for it. It works pretty well. I have machined a couple of dual stage gears with it. One problem is that one of the variables it lists as a diameter but it's really a radius. Or vice a versa. If you would like a copy of the plugin let me know and I'll email it or post it. While Cambam costs $75 you could use the trial version with the plugin. You can also animate the mechanism . Then when you see how nice it is you can buy the license. Cambam has many other nice features. But I mainly use gearotic for gears and spokes.
Dan Mauch

A couple years back, an interest in hypocyclo id gears began growing in me, particula rly the idea of using a dual stage design. I couldn't find munch informati on online in terms of the math behind them. Everythin g I found seemed to require a very specific set of parameter s. And, I wanted to build a clock with hypocyclo id rescuers, so I began experimen ting with and developin g the mechanism s on my own. I eventuall y came up with a set of equation that worked and used them to wrote a Python script to generate the parameter s for dual stage reducers. That script is here: http://www.derekhugger.com/tools/dsHypoGen.zip

The clock I made that takes advantage of this reduction method is here: http://www.derekhugger.com/riven.html

-Derek


Title: Re: Hypocycloid Gear
Post by: Dan on January 26, 2014, 03:20:20 PM
Beautiful work, Derek.

Dan


Title: Re: Hypocycloid Gear
Post by: Mooselake on January 26, 2014, 06:50:40 PM
Dan, CamBam's $149.  You must have bought it a long time ago...

It's on my to-buy list when I get quit playing around with 3D printers and get back to CNC routering .

Kirk


Title: Re: Hypocycloid Gear
Post by: mrehmus on August 15, 2015, 12:07:03 AM
I would like to know if this capabilit y is in version 2. Harmonic drives are extremely expensive, even used for us amateurs. I'd like to build a 4th axis with this type of reduction .


Title: Re: Hypocycloid Gear
Post by: ArtF on August 15, 2015, 06:23:26 AM
Hi:

  You can design them, but its messy. There only available as they are a side cousin of the cage gear. Try a cage gear as a planetary gear, that basically is a hypocyclo idic reduction . It is my plan to make a module to concatena te them to make a full reduction gearbox of them, but as
of now you can only design the one stage at a time. The math and shapes are fine and work, btu adding them otgether is above the means
of a lot of people so th eplan is to make a module that can do it. It may happen this fall. There are a lot fo desireabe l routines so Ill be
asking the users of the group what priority to assign to the ideas presented for this years developme nt period.

Thx
Art