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17498Re: "New" gearbox shot!

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  • bkelley9401
    Apr 1 12:28 PM
      It's not the gears that are at fault! You could use cast iron gears and they would fail too (not in are lifetime tough). You have gear mish-mash which is caused by the box that holds the gears.
      bkelley

      --- In RoboMower@yahoogroups.com, Danny Miller <dannym@...> wrote:
      >
      > Oh wow, I DO have replacements- 2 of them!! Yay!
      >
      > The gear ratios are conveniently labeled on 2 of them:
      > Pinion: 18T
      > then 87/22
      > then 18/82
      > then 60 for final drive
      >
      > Total ratio is 1:60.0505...
      >
      > They're labeled POM, so that's polyoxymethlene plastic.
      >
      > Yeah for belt driving, we'd have a problem. If you used 3:1 drive,
      > which is already pretty high- you'd need like 4 belts.
      >
      > There are RC gearboxes. I dunno- physically, they're much smaller and
      > most still use a plastic gear, usually meshed to a metal pinion though.
      > They're designed for less torque and much more speed. The question is,
      > is it a tougher plastic, and/or would the exclusion of dust in a sealed
      > box make enough difference?
      >
      > Danny
      >
      > On 3/31/2011 10:14 PM, Danny Miller wrote:
      > > Hmmm, actually, I could see a small gearbox with a timing (toothed) belt
      > > driving the output. There might be room for that!
      > >
      > > These motors are largely obsolete by now, brushless DC is more often
      > > used for this sort of thing. They're much smaller. Unfortunately, they
      > > require a controller that is not compatible with the motor drive of the
      > > mower. I could make something work there, but it'd be "complicated".
      > > The justification would be in the size savings if it allowed a gearbox.
      > >
      > > Awhile back we heard from someone who did take the pinions off. I
      > > assume he used a bar between the pinion and motor to bear the force
      > > (keep the force off the motor shaft) and a bearing press to punch the
      > > shaft out. But, hard to say. They could be machined with a flat to
      > > take a set screw on a replaceable set.
      > >
      > > My motor pinions are worn, but it's actually the second pinion that failed.
      > >
      > > Yeah I'm wondering if I can get a replacement. Actually, I might have
      > > one of these pieces from the old gearbox, IIRC I ordered a replacement
      > > on one of these with bearings, but later when the motor frame sagged and
      > > ripped up the motor pinions I had to replace the whole shebang with the
      > > "improved" version. Hope what I have is the right gear.
      > >
      > > Yeah
      > >
      > > Danny
      > >
      > > On 3/31/2011 9:38 PM, Dan Barclay wrote:
      > >> Where do you get the $35 gear sets? Are other parts available at reasonable cost?
      > >>
      > >>
      > >>
      > >> Last time I looked, the mowing motors were far more expensive than they should have been. I tried to get bearings replaced but the shop couldn’t get the pinion off without breaking it apart.
      > >>
      > >>
      > >>
      > >> We need (reasonable!) parts. When it makes more sense to buy a working mower and use the old one for parts, something is wrong with their strategy. I’m hoping you can show me I’ve just been getting bad info on parts cost.
      > >>
      > >>
      > >>
      > >> Dan
      > >>
      > >>
      > >>
      > >
      > >
      > > ------------------------------------
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      > >
      >
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