Subject:
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Re: Power Pullin' With My Tractor
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Newsgroups:
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lugnet.technic
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Date:
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Sat, 8 Mar 2003 13:52:07 GMT
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Viewed:
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3157 times
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Sorry for digging up an old thread ;)
In the solar car I'm building (see the 'heavily modified 8880 chassis'
thread) I've so far broken 3 old style 24 tooth gears. (among some old style
12 tooth crown gears, but that's no surprise really...)
The first one that broke was used in the gearbox, as the last reduction
before the clutch gears. It was powered by an old style 9v motor that was
being heavily overloaded by a solar panel (16 volts, 0.6 amps, almost 4
times the electrical power it's meant to be using...). The design wasn't
very good as the axles weren't supported properly.(the one with the 24 tooth
and the one with the 8 tooth gear were only supported on one side, so they
could move about a little, causing some badly alligned forces)
I basically replaced it and didn't do anything about the design.(not very
smart...)
Then, when I got a new and far more powerful (non-lego-)electric motor, I
tried it out with a virtually unlimited supply of current, and the
incredible bursts of torque destroyed the same gear after a couple of
minutes. I decided on only using batteries and the solar panel as a power
source from then on, to prevent the motor from going beserk again. :) I also
decided to use 2 couples of 24&8 tooth gears, to devide the torque in two.
That wasn't enough though, because now the stressing point has moved to
another 24 tooth gear; one that meshes with one of the gearbox' clutchgears,
and so that one broke.
It's always the axle support point that fails, never the teeth. I've now
replaced it with a 24tooth crown gear, as these look like they have that
point covered better than the regular gears. Does anyone have any experience
with that? Is the 24tooth crown gear's axle support stronger than the
regular 24 tooth gear's?
I'd like to use 2 24tooth gears connected with with 4 friction pins, but
unfortunately that's not possible there, as the 2nd one would touch the
gearbox's clutch-thingy. (no idea what it's called)
On another point in the drivetrain, that IS possible. I can even use 2 24
tooth gears with partly broken axle supports(!), by putting four friction
pins in them and then putting them together on an axle, with the broken
sides opposite to eachother. Lego reclycling :D
I was also kind of wondering is lego will replace these parts. I must admit
I'm probably putting too much strain on them, so it's not totally surprising
they're breaking down, but still, has anyone ever asked for his broken gears
to be replaced, and what kind of reaction did you get?
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Message has 1 Reply:
 | | Re: Power Pullin' With My Tractor
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| (...) Dude, this is old! :-) (...) That's been my experience too. Especially with the old-style 24 tooth gears. In fact, the axle support kinda warps as the axle rotates out. And then sometimes it just breaks. Just use the new style 24t gears. The (...) (22 years ago, 8-Mar-03, to lugnet.technic)
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Message is in Reply To:
| | Re: Power Pullin' With My Tractor
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| (...) Thanks! Okay, try it again: (URL) added some pictures to the "breakage" section that show the broken gears. I'm pretty sure that they break from the axle hole outwards. There's a high stress concentration at the point of axle connection. I've (...) (23 years ago, 25-Jan-02, to lugnet.technic)
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