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Internal gear?

Alex_Bor_3DAlex_Bor_3D Member Posts: 2 EDU
How to make an internal gear? Thank!

Comments

  • Evan_ReeseEvan_Reese Member Posts: 2,060 PRO
    if you mean a ring gear, you could get away with just making a normal gear and subtracting it from a ring too.
    Evan Reese / Principal and Industrial Designer with Ovyl
    Website: ovyl.io
  • S1monS1mon Member Posts: 2,321 PRO
    At a general level, an internal gear is the inverse of an external spur gear (hopefully with some clearance added), but as the gear ratio increases, the teeth of the internal gear needs to be adjusted. It's amazing what one can "get away with" with gears, if you just need a couple things to turn and you're 3D printing a fun mechanism. If something is being designed for low noise, high speed, low backlash, high torque, etc. then it's insane how particular gear design becomes. It gets even weirder if it's molded gears and you need to design for shrink.


  • george_homsygeorge_homsy Member Posts: 1
    if you mean a ring gear, you could get away with just making a normal gear and subtracting it from a ring too.
    Ummmmm, no.  You definitely cannot.  You *might* be able to get away with it in some circumstances, if you don't actually care about having proper gear mesh, but in general, an internal gear is different from an external.  (I think it has a negative dedendum value, or something like that...)
  • NeilCookeNeilCooke Moderator, Onshape Employees Posts: 5,310
    Two straight lines coincident at the PCD with the same pressure angle should do the trick.
    Senior Director, Technical Services, EMEAI
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