Subject:
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Re: Need to figure out how to get this motor unit attached.
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Newsgroups:
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lugnet.technic
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Date:
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Wed, 19 Apr 2006 08:17:11 GMT
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Viewed:
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7215 times
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In lugnet.technic, Geoffrey Hyde wrote:
>
> "Chris Orchard" <chris_orchard@+Remove+This+gjames.com.au> wrote in message
> news:Ixy4C6.CyI@lugnet.com...
> > In lugnet.technic, Geoffrey Hyde wrote:
> > > http://www.brickshelf.com/cgi-bin/gallery.cgi?f=171364
>
> > I think the easiest way to turn gearing through use of the worm gear,
> > however as
> > others will point out a worm gear is not very efficient gearing down
> > mechanism,
> > also if this is run for several hours at a time, the meshed gears will
> > grind.
> > Wear is even worse if the worm is the final gearing, taking the full
> > torque of
> > the application. So use a worm earlier rather than later in a gear train.
>
> The worm gear pics that I loaded into the folder recently are for a one-way
> worm gear drive. This basically is so I can set the hopper on and forget
> about what direction the motor has to turn in.
One-way can also be done with an gear on the pivot of an arm meshing with an
idler gear on the end that swings between two close gears. You wouldn't have to
go through any 90 deg twists then. :P
> > The most effective gearing down is via double bevel gears as the gear
> > teeth are
> > wider (more contact and strength, less pressure).
>
> Double-bevel gearing down is possible, but wastes power if you have more
> than a few gears in the geartrain.
I could be wrong, but I thought that the sliding friction of one worm was worth
serveral straight cut gear reductions. Basically you picked a worm if you
wanted the locking feature, or couldn't afford the room.
> I actually found that the 12 tooth gears interfaced with the worm gear
> pretty well, maybe had a few problems with slippage when reversing the motor
> direction, but since I'm just going to turn the motor on and let it run, I
> do not forsee that being a problem. My aim here is 'set and forget'
> operation.
Ok, I wasn't sure how much info to give or at what level, I erred on side of
verbosity :) The 8 and 24 tooth work great with the worm in studless, but the
12t double bevel? Any chance of seeing the set up? I've never gotten a really
good mesh using studless.
> > Just as a side question, does anyone know how efficient the four-lobed
> > pseudo
> > gear is compared to bevels and worms?
>
> Which part ID # are you talking about here?
32072 <http://www.peeron.com/pics/inv/custpics/thumbs/32072.1103860997.jpg>
> What I was looking for was one-way drive, if you have a way to accomplish
> this at a ratio comparable to worm gear reduction as shown, and in as few
> parts, please do let me know.
No, not in as few parts :)
Have you tried mounting the motor vertically? you could use
<http://media.peeron.com/ldraw/images/0/32009.png> to put the motors' shaft in
line with the worm, then your "one way worm" goes through the 90deg for you.
Once both axis of the input and output are in line, it should be pretty trivial
to connect it through. I'd put an axle joiner on the motor so you can brace
either side of the slip-gear/worm-input and move the worm closer to the conveyer
inputs. As the worm floats anyway, it will only have to be mildly rigid.
> > Other options include mounting the motor via 6536/32184 (below)
> > Any way you go I'd make the turn before any gearing down.
>
> That mounting option might do but not for strength. And particularly not
> for a studded motor.
>
> > Another question that arises is when the slip-gear should be placed in a
> > gearing
> > down train. I'd assume that the earlier you place it, more force is
> > required
> > (at the output) to stall the train. Is this right gurus? (Rosco et al?)
>
> I have seen from looking at gear trains that if one turns the little end
> (the output which is driven slowly) considerable force is required to turn
> that axle slowly around while the gear train can speed up quite a bit at the
> input end. If slip gears should be placed anywhere, it should be where
> there is likely to be a large amount of backlash in a gear train due to
> stalling.
I thought you'd want it so there was enough torque to drive your app, but if the
output is stalled, not enough torque can be generated, before slippage, to cause
damage. Is that what your saying about backlash?
> > All of these and more is possible, I'm afraid that the only way is through
> > a bit
> > of trial-and-error, but that is the "fun" bit of lego for me. :)
>
> I know what you mean mate, I've thrown out almost an entire galaxy's worth
> of theories, as the practical solution(s) yield to my inexperienced building
> skill. ;-)
If the theory doesn't fit, just change it a little, then rebuild from scratch
anyway ;)
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