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Question Linear Actuator Side Load

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by Erik Green, Sep 3, 2019.

  1. Erik Green

    Erik Green Member

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    My Motion Simulator:
    6DOF
    To look at a Stewart platform from a theoretical standpoint, I wish assume there is zero side load (radial) on the actuators in operation. In real world operation is there any major side load/friction between the extension shaft and it's bearing?
  2. Ads Master

    Ads Master

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  3. JAD

    JAD Active Member

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    I'd suggest your correct in assuming near zero side loads.
    The negligible lateral loads would come from self weight due to the actuator leaning over from the vertical.

    My actuators are 'frameless' and more susceptiple to lateral loads and for me its so far so good. The double ball nuts help also.
    But without the extra lateral support somewhere along the tube extension length, it makes the effective length extra long, and so my actuaotors suffers from vibration more easily.
    Its not a show stopper and Im getting comfortable with the vibration, but not ideal.
    IMG_20190728_172031 (1).jpg
    • Informative Informative x 1
  4. lromaniuk

    lromaniuk bny

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    In general Stewart platform made of linear actuators is an example of truss https://en.wikipedia.org/wiki/Truss thus forces acting on actuators are tensile or compressive. A ball screw holding a load is prone to buckling. Buckling load is one of the parameters of a ball screw (you can look it up in ball screws data sheet). Exceeding maximal buckling load will result in excessive ball screw and nut wear and mechanical failure. Speaking of this, a ball nut has some tolerance when fitted to ball screw thus it should be supported with some kind of guide or it will be more prone to buckling and its consequences. Vibrations that @JAD is experiencing are consequence of ball screw buckling. Also noise coming from ball screws actuators might be related to radial forces that are there due to buckling.
    • Agree Agree x 1