7 Replies Latest reply on Aug 6, 2010 10:05 AM by 1-IO6KWW

    Contact Help

      I am trying to do a simulation of two face gears meshing together to create a fixture when bolted together. There are 72 teeth,  allowing 5 degree increments when unbolted. I'm trying to figure out how to create a contact between the gear teeth to see if they will be strong enough. I'm fairly new to SolidWorks Simulation. I've tried automatically finding contact sets, but it doesn't seem to find anything. Any help would be greatly appreciated.

       

      Thank you,

      Peter

        • Re: Contact Help
          Roland Schwarz

          Try creating contact sets between specific sets of faces using the "No penetration" option.

          • Re: Contact Help
            Devi Prasad Samal

            Hi peter,

             

            may be the automatic find contact sets option does not work because at the starting of simulation the faces are not connected with each other. some times during applying forces some faces comes in contact with each other. hence at that condition we have to manually put no penetration contact between the selected faces.

             

            So try to add contacts manually between the faces which u are sure about that they will be come in contact during the force application.

             

            Hope this helps.

             

            Regards

            Devi Prasad Samal

            • Re: Contact Help
              Kevin De Smet

              This also seems like a situation where you could employ symmetry to make the simulation go faster and avoid the tedium of making 72 contact sets manually.

               

              Not sure though since gear interactions seem like kind of complex phenomena.

              • Re: Contact Help
                Ryan Werner

                I am not sure what you mean by face gear.  How are you applying your forces and restraints?

                 

                Since the teeth of the gears are curved surfaces they are only going to be pushing against each other at the point of contact where the two surfaces are tangent to each other at any given instant.  So, at best you will have to choose a point in time where the two teeth are touching and then create a split line at the point of contact for both gears and then you can create a contact set along that line.  I have done similar studies in the past but only on an individual gear at a time so as to avoid this contact set issue.  Also, depending on how large a force or torque you are applying, you may see some high localized stress and possibly deformation along the line of contact that is not really accurate.

                 

                I hope this was a bit of help.

                 

                Ryan W.

                  • Re: Contact Help

                    Sorry for the delay, we decided to go with another design. I'd still like to work on this though. This is a sample picture of what the parts would look like. The first is as they would set when bolted together, the second is an exploded view showing what I mean when I say face gear.

                     

                    I think part of the problem is the computer I'm working with. It just takes too long to really try any of your suggestions. I will have to try on my computer at home.

                     

                    Thank you,

                    Peter

                      • Re: Contact Help
                        Ryan Werner

                        The pictures defintely helped clarify things for me.  Thanks.

                         

                        Do the teeeth contact each other when they are meshed?  They may not since you probably designed them with some tolerances to make sure they would fit nicely together.  I would start by making sure that when they are meshed the teeth are all contacting each other.  Then go ahead and create the no penetration contacts between the faces.  Unfortunately, no penetration contacts can take forever to solve.  If you want to run something quicker than just leave all the faces touching and Simulation will assume they are bonded and then you will be able to get results much faster.  It will not be totally accurate but it might give you an idea of the stress.

                          • Re: Contact Help

                            I designed them with no clearances (I just wanted to see how they would perform). Ideally there would be very little play in them though. It's for a fixture to set specific angles and we can't have any variation in the angles. I'll try the stuff you suggested when I get home.

                             

                            Thanks,

                            Peter