15 Replies Latest reply on Dec 4, 2018 6:25 AM by Marcos Rodríguez

    Worm wheel sweep path and involute

    Marcos Rodríguez

      Form.JPGDear people,

       

      Here it's attached a super macro, creating the path for creation of a worm wheel gear. it also creates the cross section as an involute profile.

       

      It creates global equations, so if you run it twice with different values in same part, it won't overwrite the values, you need to delete the global equations manually before hand.

       

      Message was edited by: Marcos Rodríguez Upload Version-2 of Involute with some improvements in the 2D section creation, and a correction in the 3DParametricEquation

       

      Output 2d & 3D Sketch.JPGCapture.JPG

      Capture.JPG

       

      Macro updated, with simplifications at 2D Cross section creation

        • Re: Worm wheel sweep path and involute
          Terry Raymond

          Cool! Thanks for sharing.

          • Re: Worm wheel sweep path and involute
            Bob Eppig

            I just tried it.  All I get is 1 3d curve sketch.  What is going on?

              • Re: Worm wheel sweep path and involute
                Marcos Rodríguez

                Hi Bob,

                 

                The 3D Curve will be the path of a SweptCut Feature. And this is the most innovative of this macro. This 3D curve is driven by a equation developed by me.

                 

                The 2D Sketch needs to be completed, it holds an involute curve driven by equation. You must close section, with the addedum circle, that depending of number of teeth and pressure angle, sometimes is bigger than base circle.

                 

                You need to create your own wheel blank, to cut with this swept, and once there make a pattern with all number of teeth.

                 

                Finally, this is just something aproximated. The real way to make a wheel gear is more complicated. You need to bear in mind the normal module, place the 2D sketch in a plane perpendicular to the helix. Wheels are made with a bigger diameter tool than the PCD worm, etc..., different shape (not involute profile)

                 

                Good luck.

              • Re: Worm wheel sweep path and involute
                Asko Kauppi

                Unfortunately, I get this when running the macro:

                 

                VB error.PNG

                Pressing 'Debug' shows this:

                debug.PNG

                 

                Is this of any help?

                 

                Steps:

                1. Created a new part (it does not seem to matter)

                2. Tools > Macro > Run > (select the Involute.3.swp file)

                  -> Dialog pops up.

                3. Pushed OK (default values)

                Expected:

                - something added to the part

                Actual:

                - the error dialog

                 

                Disclaimer:

                This happens on Solidworks 2019 Beta 3. Unfortunatly, I am not able to test with SW 2018. Would just want to know whether I am trying to run it the right way:

                  • Re: Worm wheel sweep path and involute
                    Deepak Gupta

                    Asko Kauppi wrote:

                     

                    Disclaimer:

                    This happens on Solidworks 2019 Beta 3.

                    Please no discussions related to beta over here. Kindly post your questions/issues in beta forum only.

                    • Re: Worm wheel sweep path and involute
                      Marcos Rodríguez

                      Hi Asko,

                       

                      Thanks for your interest.

                       

                      Macro works well in 2018, haven't got the chance to try it on 2019.

                       

                      You can try to debug it, to see where it cracks.

                       

                      In that point it is building the 2D Sketch, it looks like the involute hasn't been created, for any reason, you can scroll the yellow arrow upwards and query all the objets if are set to Nothing or what?

                       

                       

                      Anyway, the 2D sketch is not the most interesting, you could skip that ant run the last part of the code, that is the 3D Curve.

                       

                      Regards.

                    • Re: Worm wheel sweep path and involute
                      Josh Leedle

                      I am not getting a box to input the Wheel PCD, is there a fix for this?

                        • Re: Worm wheel sweep path and involute
                          Marcos Rodríguez

                          Hi Josh,

                          Thanks for trying my macro

                          The wheel PCD is result of Module * N° of Teeth. These are the only parameter you can introduce for the wheel

                           

                          I should have removed ir, but my intention was to give the user the chance to introduce either parameter, but my knowledge of Visual Basic with forms is a little bit dispairing.

                           

                          If you can make it a little bit better, I challenge to do it, and send me the results.

                          I am pretty sure the community would thank you.

                           

                          Otherwise I may find a second to do it myself.

                           

                          Regards.

                            • Re: Worm wheel sweep path and involute
                              Josh Leedle

                              Tank you for the reply, I will continue to experiment with it.

                               

                              My question is once you have the 2D and 3D sketches how do you generate the helical curve to contour around the gear like in the bottom two images?  This is actually the feature of this Macro that I am needing for the part design I am working on.

                                • Re: Worm wheel sweep path and involute
                                  Marcos Rodríguez

                                  Hi Josh,

                                   

                                  Either you didn't attach any image or do you refer to my initial bottom images??

                                   

                                  The macro, as explained upwards, makes only the cross section in a 2D Skecth and the path, in a 3D Skecth for the worm wheel gear. Nothing for the worm.

                                   

                                  This will allow you to create a sweep cut to a wheel, that previously you would have had to model up. Once you do this sweep cut, you'll need to pattern by the number of teeth.

                                   

                                  If you research deeper, you'll find that there are also different options to located the 2D profile, where the 2 main ones are either perpendicular to the trajectory, or parallel to the middle plane of the wheel.

                                   

                                  The reason why I didn't include the blank wheel, it's because there are many different standards, forms, shapes, etc...

                                   

                                  If I've got time for Xmas, I will update the macro to create a basic blank wheel, create the sweep cut, and the pattern. And maybe worm too.

                                   

                                  Happy Xmas.

                                    • Re: Worm wheel sweep path and involute
                                      Josh Leedle

                                      Thank you,

                                       

                                      I understand that I need to have the geometry to perform the sweep cut on.  What intrigued me and the feature I am needing, as it is not for a worm gear, is the helical curve around a circle such as the last two images you posted also reposted here..  It may be a patterning but it looks to be a helical traced along a 180 degree arc.

                                       

                                       

                                       

                                       

                                       

                                      Capture.JPGCapture (1).JPG

                                        • Re: Worm wheel sweep path and involute
                                          Marcos Rodríguez

                                          Hi Josh,

                                           

                                          Thanks one more time for your interest. Actually that curve is the main goal of this macro. In another words, this macro is a interface to create that curve. That curve has taking me a while to develop, but it's basically the combination of a circle and a helicoid.

                                           

                                          Once it's inserted with the parameters of you worm/wheel set, you can actually see the equation and edit.

                                           

                                          Modifying the values t1, t2 alters the beginning and end of the curve. This is basically the number of degrees in radians, being the total turns the number you've introduced for the teeth.

                                           

                                          Just note:

                                          1 turn = 2*pi radiands

                                           

                                          So, you can play around and get different lengths.

                                           

                                          Enjoy it!!

                                • Re: Worm wheel sweep path and involute
                                  Daen Hendrickson

                                  Marcos Rodríguez, will your macro be appropriate to use for fine-pitch worm / worm gear sets - on the order of 360:1 ratios? I am just familiar enough to know that fine-pitched geometries make some approximations and other variances that you would not necessarily find with a worm/gear set intended for power transmission.

                                   

                                  Thanks and looking forward to trying your macro.

                                   

                                  Daen

                                   

                                    • Re: Worm wheel sweep path and involute
                                      Marcos Rodríguez

                                      Hi Daen,

                                       

                                      Thanks for your interest.

                                       

                                      Well first clarify that the main purpose of this macro is to provide a 3D Curve to make the sweep cut. And get a more realistic result than any other I've seen so far. I worked in a factory of low power DC motogears, and these worm wheels were machined and heat treated, and machined again. The process as you say, is far away from the theoretical shape modeled in SW, but at least provides a uniform surface twisting and rotating.

                                       

                                      Said this, yes, if you provide the number of 360 teeth to the macro with the module, then you'll get you piece of trajectory, that's just maths, no magic. Other different thing is the 2D involute profile, I'm not sure what will happen there.

                                       

                                      I've just tried, and the 2D involute didn't work very well. However you could draw just some arcs or even straight lines. But the 3D tarjectory looks fine.

                                       

                                       

                                      By the way, standard wheel don't go over 200 teeth.

                                       

                                      Regards.