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Globoid Thread

warren_pegleywarren_pegley Member Posts: 10
Hello Onshape & Community,
The Battle with gears continues, a very efficient way to transmit power thru a worm screw is the Globoid worm & wheel, 2. Things I noticed while trying to set up an automatic worm & wheel gear generator.
The 1.engine & 2.I really struggled, lol. it was probably mostly me.
https://cad.onshape.com/documents/46d09a55cf5c494774217aff/w/1be0655855093799140a00c6/e/6aeca6601d67336785e60f85
Please take a look at this document, Several attempts to create a Globoidal profile via functions failed as show in the gear document, then this document was created to trouble shoot, all geometry was constrained and this helped but whist trying to sweep the tooth profile into a new solid -it went red and looked ok but would never go go blue on either the normal sweep or sweep functions, finally I got the surfaces to what I thought was ok with hope to fill or thicken them followed with a boolean to create the final worm wheel, How ever once sectioned the geometry is incorrect thru 180 degrees, 
I got this far via following mostly Cody's & Ians (& others - you know who you are you Cad perverts) tutorial on youtube, However due to a spinal Injury mostly sedated whilst so.......  
So forgive me for reaching out but once addicted to power transmission always addicted. 
A tutorial on setting up a globial worm & wheel, with parrameters, = 'Functions' would smash all other CAD platforms out of the preventable water.
FYI


Comments

  • warren_pegleywarren_pegley Member Posts: 10
    *Preverable 
  • warren_pegleywarren_pegley Member Posts: 10
    Great to chat to the Legend that is Konstantin, I was the one who liked this document sadly I could not follow your work, I was lost, there are features that had no info sheet and sketch 2 before sketch 1 ect ect, The reverse engineering of that document would take some time without a little more info.  
  • konstantin_shiriazdanovkonstantin_shiriazdanov Member Posts: 993 ✭✭✭✭✭
    I made a simplified part studio for globoidal worm only:
    the most complex thing which happens there is creating worm tooth spiral. I use a curve generator feature to build the tragectory of a point on the worm wheel in its relative motion around worm itself. For this i define an angle of rotation of the worm wheel Phi, then make a sketch with the point which rotates around wheel axis at Phi, define mate connector as worm coordinate system on the worm axis and rotate it around it's z axis at Phi*u angle (u is the gear ratio). And then use curve generator in which I select wheel point sketch, worm mate connector as local coordinate system, variable name, variable bounds and iteration step. And the feature generates kinematic trajectory of the point relatively to the coordinate system selected.
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