Subject:
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Re: My Lego planetary gear
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Newsgroups:
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lugnet.technic
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Date:
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Wed, 4 Oct 2000 07:12:14 GMT
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Viewed:
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866 times
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That alternative implementation gives me an idea. What about putting gear
wheels around on arms sticking out at various angles and held together by
structural Technic parts, and having various combinations meshing with each
other?
The only problem is that it might be a bit bulky in places. Fortunately,
there are plate height and brick height beams available and they look like
becoming available in more and more sizes too.
The sun/planet concept is fairly simple, I believe early automatic motorcar
transmissions used them. The more recent ones use a variant similar to the
hydro-electric power plant.
Cheers ...
Geoffrey Hyde
Amnon Silverstein <amnon@best.com> wrote in message
news:G1w2qn.MwF@lugnet.com...
> Ah. Hm, I wonder if it could be used for a lego transmission. I cleaned up • my
> first planetary gear, and I came up with a second implementation. It is
> bigger, and it is not obviously a planetary system, but I think it is
> topologically equivalent. It has easy access to the three rotating • components.
> Here is my old design cleaned up:
> http://www.best.com/~amnon/Homepage/Games/Planet1.jpg
> http://www.best.com/~amnon/Homepage/Games/Planet1Parts.jpg
>
> And here is my alternative implementation:
> http://www.best.com/~amnon/Homepage/Games/Planet2.jpg
> http://www.best.com/~amnon/Homepage/Games/Planet2Flat.jpg
>
> -Amnon
>
>
> In lugnet.technic, Ross Crawford writes:
> > You can actually get very similar behaviour using a standard • differential.
> > If you hold one "output" shaft, and turn the other, the crown wheel turns • at
> > half the input speed. The advantage of planetary gears is the output • shaft
> > is in line with the input shaft, making it easier to chain them together. • A
> > lot of old cars used this technique - the output of the first was • connected
> > to the outer ring of the second, and so on. Locking the last one in the
> > chain gives you low gear, locking the next gives you a higher gear (by
> > "reducing the reduction") and so on. Big advantage of this technique is
> > there's no real need for a clutch.
> >
> > Regards,
> >
> > ROSCO
> >
> > Amnon Silverstein <amnon@best.com> wrote in message
> > news:G1vopu.J1C@lugnet.com...
> > > By locking the outer ring, in acts as a 2:1 or 1:2 gear (depending on • which
> > > shaft you use as input and which as output. If you lock the planets, it • turns
> > > into a 1:1. If you let everything loose, it is a neutral gear. If you • lock
> > the
> > > output shaftand tap off of the ring somehow, it could act as a reverse, • but in
> > > practice this has a few problems. The planets and the sun gear tend to • jam
> > and
> > > the gear drag is pretty bad.
> > > Yeah, if Lego made some real parts for this, it would be much easier to • rig up
> > > a multi-speed transmission with reverse.
> > > This works well enough to demonstrate the principles of a planitary • gear
> > > system, at least.
> > >
> > > In lugnet.technic, Geoffrey Hyde writes:
> > > > That is certainly compact. Do you have any ideas how it might be used • in
> > an
> > > > actual model? I suppose locking either the top half or the bottom • half,
> > or
> > > > both, would change the way the output shaft differs from the input • shaft?
> > > >
> > > > Although what I would really like to see is an inner gear ring which • is a
> > > > lot larger than the current gears are. I'm not sure if it's • technically
> > > > feasible to make, though!
> > > >
> > > > Cheers ...
> > > >
> > > > Geoffrey Hyde
> > > >
> > > >
> > > > Amnon Silverstein <amnon@best.com> wrote in message
> > > > news:G1u5JH.BMp@lugnet.com...
> > > > > I was working on transmission ideas, and I came up with a cute • planetary.
> > > > It
> > > > > can produce several different types of output, and it is typically • used
> > in
> > > > > transmissions. My implementation is compact, and doesn't use too • many
> > > > parts.
> > > > > I'm not sure that it is useful for anything, but it might be cool in • a
> > > > > gearhead-nerd way.
> > > > >
> > > > > http://www.best.com/~amnon/Homepage/Games/PlanetMiddle.jpg
> > > > > http://www.best.com/~amnon/Homepage/Games/PlanetTop.jpg
> > > > > http://www.best.com/~amnon/Homepage/Games/PlanetBottom.jpg
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Message has 1 Reply:
 | | Re: My Lego planetary gear
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| (...) Planetary gears are still being used as maintainance-free transmission systems for bycicles, build inside the back nave. They work very well, I own a bike that has 7 gears crammed inside a ±10 cm diameter hub. Greetings, M. Moolhuysen. (24 years ago, 4-Oct-00, to lugnet.technic)
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Message is in Reply To:
| | Re: My Lego planetary gear
|
| Ah. Hm, I wonder if it could be used for a lego transmission. I cleaned up my first planetary gear, and I came up with a second implementation. It is bigger, and it is not obviously a planetary system, but I think it is topologically equivalent. It (...) (24 years ago, 4-Oct-00, to lugnet.technic)
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