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Limit the RPM of output Shaft having variable input RPM from another shaft

  1. Nov 3, 2011 #1

    Shaft A has variable RPM, getting input from some rotating element (say X), ranging from 0 to 2000.
    The RPM of X cannot be adjusted or controlled.
    A has to transfer the rotation with limiting RPM of upto 400 to Shaft B.

    Is there a way to limit the RPM using a mechanism such that at particular RPM, Shaft B have constant RPM irrespective of Shaft A RPM.


    Shaft A RPM= 350 Shaft B RPM= 350
    Shaft A RPM= 400 Shaft B RPM= 400
    Shaft A RPM= 1200 Shaft B RPM= 400
    Shaft A RPM= 2000 Shaft B RPM=400

    Also I would like to mention that due to space constraint a bulky system/mechanism cannot be accommodated. Thus I want a small system of nearly or less then 6 inches(LBH) size.
  2. jcsd
  3. Nov 3, 2011 #2
    This is what a transmission does.
  4. Nov 3, 2011 #3
    Thanks for updating my knowledge, but my query is still unsolved. I m looking for a mechanism which is smaller in size and whose resistance effect to rotation is almost negligible.
  5. Nov 3, 2011 #4
  6. Nov 3, 2011 #5
    Friction gearing would lead to wearing of the fiber and my perception with CVT is that it will offer high resistance to rotation. I am looking for something which do not offers high resistance to rotation and is much more like maintenance free.
  7. Nov 3, 2011 #6
    ...Sorry, but tough luck...

    MAYBE if you developed your own control method and magnetic coupling design (something like a Powered & Free design). But I don't see this working; and I see it being very expensive and finnicky.

    Think about what you are asking:

    --You want to turn down 2000 RPM to 400
    --You want negligible resistance
    --you want negligible wear
    --you want minimal maintenance
    --you want it to be less than 6 in. (in any dimension?)

    I don't want to discourage you, but engineering is about optimizing not idealizing.
    Last edited: Nov 3, 2011
  8. Nov 3, 2011 #7
    Take a look at the operation of the hybrid synergy drive, too
    Last edited: Nov 3, 2011
  9. Nov 4, 2011 #8
    A variant of an overrunning clutch would do the job. It totally depends on how the shafts are connected, which I can't visualise from the above.

    Input shaft geared down then a clutch based on the output shaft speed that would disengage (fully or slip) at 400 rpm.

    If you didn't need to do it mechanically, ie you had a control system and some acutators. It'd be easy.
    Last edited: Nov 4, 2011
  10. Nov 4, 2011 #9
    Fo Sho
  11. Nov 5, 2011 #10
    @ Travis: Thanks for providing the information of hybrid synergy drive but I can't find anything useful as req. If you could just suggest me some better mechanism.
    @Chris : Thanks for the input. If you could just suggest me some specific overrunning clutch system as per my req.
    The system just requires an intermediate mechanism to limit the RPM of the shaft.
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