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Author Topic: Anti-backlash gearing  (Read 144 times)
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bruce
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« on: June 18, 2018, 09:39:09 AM »

I did a search here on the subject of anti-backlash gearing and came up empty.
So I am asking the question about anti-backlash gearing and don't think there is any info in the gearotic software about this or specifics
in the way to implement them.
I see where springs are added to make one gear take up any backlash against a fixed gear. I know that depending on the size and strength
of the spring will limit the amount of torque that can be applied while the backlash is taken up.
In the applicati on I am thinking of all I want to do is transmit this rotary motion to an encoder so there isn't much force needed to make
sure the gear teeth stay engaged without backlash.
Just need to figure out the geometry of adding the spring(s) to at least 1 set of gears (spur) while the pinion at same size is without any
anti-backlash mechanism s.
Just wanted to run this by the forum for suggestio ns and comments.
Is this something that could be added to Gearotic?
TNX,
Bruce
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ArtF
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« Reply #1 on: June 18, 2018, 10:04:10 AM »

Hi Bruce:

   Theres a couple of ways to do this, dynamic and static. If on the design screen you lower the
tooth width to .3 or .4 on one gear only, it becines a loose fit. If you now make two of that
gear and make them half the face width, you can then tighten one on its shaft and slightly rotate
the other as you tighten it on the same shaft creating any tightness you wish and lock it. This
is a method of allowing a static backlash that you need to adjust if theres any wear.
  The other method is just to attach the second gear to the first with a spring on a tab created
by modifying the gear in dxf and getting clever with how to place the spring. That sort
of backlash correctio n is dynamic and will stay tight over time. With an encoder though, I suspect
the first option would work fine, though Id just make the slot for the encoder shaft elongated
and adjust the encoder closer till its a tight fit myself.

Art

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bruce
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« Reply #2 on: June 18, 2018, 10:33:52 AM »

Thanks Art for the info but on that last sentence:
"though Id just make the slot for the encoder shaft elongated
and adjust the encoder closer till its a tight fit myself."

So the tooth peak never hits the tooth root which means you can
adjust the mesh to where it is somewhat tight? Do I have that correct?
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ArtF
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« Reply #3 on: June 18, 2018, 12:01:01 PM »

Hi Bruce:

  Yes, you can for example, stub the tooth a touch so theres no hit on the roots trochoida l ,
or in many instances you can slightly widen the tooth to .51 for example which allows a tighter
contract when slightly moved outwards.  You needent worry usually on an encoder toothing
when high speeds arent likely.

Art
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