Hypocycloid Gear

[Dan]

Funny they never mention the main advantage that we ascribe to hypocycloids - 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

[dhugger]

A couple years back, an interest in hypocycloid gears began growing in me, particularly the idea of using a dual stage design. I couldn't find munch information online in terms of the math behind them. Everything I found seemed to require a very specific set of parameters. And, I wanted to build a clock with hypocycloid rescuers, so I began experimenting with and developing the mechanisms on my own. I eventually came up with a set of equation that worked and used them to wrote a Python script to generate the parameters 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

[ArtF]

Derek:

  That is one excellent piece of timekeeper.  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 information..

Art

[danmauch]

Really nice work. You probably could have saved yourself some time if you used CamBam. There is a hypercycloid 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 hypocycloid gears began growing in me, particularly the idea of using a dual stage design. I couldn't find munch information online in terms of the math behind them. Everything I found seemed to require a very specific set of parameters. And, I wanted to build a clock with hypocycloid rescuers, so I began experimenting with and developing the mechanisms on my own. I eventually came up with a set of equation that worked and used them to wrote a Python script to generate the parameters 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

[Dan]

Beautiful work, Derek.

Dan

[Mooselake]

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

[mrehmus]

I would like to know if this capability 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.

[ArtF]

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 hypocycloidic reduction. It is my plan to make a module to concatenate 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 desireabel routines so Ill be
asking the users of the group what priority to assign to the ideas presented for this years development period.

Thx
Art