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Small Pinions

Posted: Thu Nov 09, 2017 6:51 am
by John T
Hi Art,
On my latest project the pinion on the Great Wheel of 75 teeth  drives a 6 leaf 1" diameter pinion.  That's going to be put the pinion under a lot of stress.  My solutions are to cut a leafed pinion of brass - should be OK

The other solution is to cut a cage set with the wheel having 75 teeth and the pinion having 6 pins.

My question is - does the backlash option have any effect in this case.  I can select  0% up to 10% as shown but I don't know where to look for the effect of the backlash setting i.e. what happens to the design.

Re: Small Pinions

Posted: Thu Nov 09, 2017 4:32 pm
by ArtF
Hi John:

  Is this in the old Gearotic 1.0 ?

  I didnt think I put backlash in Gearotic 2.0, I recommend instead, if one needs backlash, to set the tooth width slightly less than .5. This makes the teeth of one gear a bit thinner. Or, set both thinner. Zoom in on the teeth and watch what happens if you set both to .49 width. This is a much safer was of doing backlash as it keeps shafts the right distance apart for the module gear used. In Gearotic2.0 use tooth width. In Gearotic 1.0, setting backlash sets the shafts slightly apart. Set to 5% or so was a decent backlash.

Art

Re: Small Pinions

Posted: Fri Nov 10, 2017 3:08 am
by John T
Hi Art,
I should have included a little more info the first time.  This is version 3.02
I appears to be moving the shafts.  I can't get a really good measurement of the shaft spacing but the best I can get says as 0% it is 3.3735 while at 10% it is 3.3537

I've attached a couple of screen shots which show the backlash but there is no tooth width options for the cage

Re: Small Pinions

Posted: Fri Nov 10, 2017 5:18 am
by ArtF
Hi John:

Sorry about that , I was thinking spurs and the changes to backlash over time.

In the Cage gears, backlash shrinks the pitch circle of the hypocycloidal spur, it does
nothing to the cage gear. So in your case , using a cage with a spur backlash would
have no effect, but you can get backlash in that case by simply using smaller diameter
pins.

Art