1 Reply Latest reply on Mar 14, 2011 6:36 PM by John Sutherland

    Simulation of a Steering Gear

    Ceri Gittins

      Hi there !

      I've been using SolidWorks now for the past few years, but only really to 
      design & optimise assembly equipment, quite frankly the computer 
      equipment I have in work is really poor, however this week I'm finally 
      having a new workstation so i'm hoping I can start to get into simulation 
      & analysis.

      On one of our assembly lines we build manual steering gears that are 
      then fitted into vehicles with C-EPS (Column Electric Power Steering) but 
      we are having problems sometimes with the rotational torque of the 
      assembly & I would like to utilise SolidWorks if possibly to simulate the 
      gear assembly & change certain features of the individual components to 
      see the effect on the rotational torque pattern.

      The gear is a rack & pinion design, and has some other components in 
      contact with it, one being a bush & the other a support yoke & spring 
      assembly that keeps the gears in mesh. 

      Would it be possibly to simulate the movement of the steering gear 
      through it's entire stroke & generate a graph showing the rotational 
      torque required on the pinion shaft through the entire range of movement 
      ? thus then by changing some of the component parameters, maybe helix 
      angle of the pinion, or over-pin diameter of the rack, or frictional 
      coefficient of the support yoke in contact with the rack, or the spring 
      force that keeps the yoke in contact with the rack, I can then re-run the 
      simulation and see how these changes effect the torque curve ?

      We have tried to do swap tests with the components from a good / bad 
      gear & also measured the components, so if I can use SolidWorks to run tests & only 
      change one variable at a time then hopefully it can help me pinpoint the 
      root cause of the torque fails

      As i've not run any simulations / analysis yet then any help pointing me in 
      the direction of some tutorials & firstly even if it's possible to do what I 
      want within SolidWorks !

        • Re: Simulation of a Steering Gear
          John Sutherland

          This question belongs in the Motion Analysis (or whatever they call it now) category.

           

          My experience suggests that you could invest years of work into modelling your mechanism and end up with no result.

           

          I expect that you will need to combine 3D contact with friction between the contacting faces.  SW Premium invited me to attempt this then disqualified my attempt.  Like Lucy and Charlie Brown with the football.

           

          The advice I received was to simplify my model, but I would then be modelling someone else's mechanism and not mine.

           

          My force result charts showed random noise spikes, and damped oscillation after every pertubation of the mechanism.  I did not show the chart to my peers or attempt to argue that the oscillation would be detectable on a physical  prototype.

           

          Tutorials show you how to solve someone else's problem.  They probably demonstrate the limits of what SW can do.

           

          But you should still give it a go and tell us what you find.