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  • Help regarding geared mechanism

    Discussion in 'The main mechanical design forum' started by Qaiser, Feb 26, 2013.

    1. Qaiser

      Qaiser New Member

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      Hello Everybody!
      I want some help designing a mechanism, I hope someone here could do that. The description is given below.
      I have got two concentric shafts. Outer shaft is output shaft & inner is input shaft.
      Both shafts rotate in the same direction.
      Outershaft rotates with half the speed of inner shaft.
      Dia of outer shaft is 80mm & inner shaft is of 50mm.
      Only one pair of gears is to be used.
      How I am trying to solve this problem is that one internal spur gear should be attached to outer shaft and one spur gear with inner shaft but at some off centre(i.e. at some distance from the centre of the shaft). Will this arrangement of gears work?
      Suggestions required.
      Thanks!
       
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    3. mhjones12

      mhjones12 Well-Known Member

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      To make sure I'm picturing this right, it sounds like you're describing something like a planetary gear train with only one planet, no sun gear, and where the planet carrier is held fixed? (Concentric, by the way, means the shafts have the same center, but what your describing has different centers, right?) I've never seen this configuration before, and a quick web search doesn't turn up anything. If using more gears is a possibility, then you can use a typical planetary gear train, with the center shaft connected to the sun gear (input) and the outer shaft connected to the planet carrier (output). With the ring gear held fixed, the sun gear and the planet carrier would rotate in the same direction. Then you just have to choose a gear configuration that gives you a 2:1 ratio. In this design, the shafts would be concentric.
       
    4. Qaiser

      Qaiser New Member

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      @mhJones12. I really appreciate your suggestion. Shafts are concentric, i.e. they have same center. I will consider using planetary gear train. But my real question is, Is there any configuration where I can use only one set of gears? If that is not possible then I will definitely use planetary gear train.
      Thanx.
       
    5. mhjones12

      mhjones12 Well-Known Member

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      If the shafts have to be concentric then I see no way to use only one pair of gears. Planetary gear train seems the best way to go.
       
    6. shyamdikshit

      shyamdikshit Member

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      Your idea will not work using only two gears.
      Planetary gears will give you high speed reduction.

      You will need four gears to get efficient power transmission.
      One gear on inner shaft. One on outer shaft. Two fixed to each other on pin mounted on external structure.
       
    7. Benoit

      Benoit Member

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      The internal gear on the outer shaft (really a tube!) is ok, but only one gear on the internal shaft looks impossible unless the two shafts are parallel to each other, not "concentric". If they must be concentric, you need two more gears to operate this system.
      Have a great day: Benoit Ventimiglia.
       
    8. Rohan Thapar

      Rohan Thapar New Member

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      Well in my view if you could play with the diameters of the gears then of course we would have a solution with single pair of gears but with a difference of 30mm, I think it isn't possible. A gear train mechanism could be helpful, as mentioned by one of the post above, but again that will not solve your question . Your answer to the question is no , you can't do it using single pair of gears.
      Regards,
      Rohan Thapar
       
    9. Benoit

      Benoit Member

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      Finally we do not know what Mr. Thapar wants to do with those two shafts ??? May be there is a simple way to accomplish the same task. Remember: "There are 101 ways to skin a ....t" Maybe lets look at it in a new way. Have a great weekend folks: Benoit Ventimiglia.
       
    10. Rohan Thapar

      Rohan Thapar New Member

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      I meant a very simple solution , reduce or increase the gear diameter(any one) , which will enable the pitch circle and the addendum circle interact.If you could relate it to spur and pinion. Thus,positive drive without slippage.
       
    11. Benoit

      Benoit Member

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      You have not addressed my question: What is that you trying to accomplish? May be there is a simpler way to do it!!!!
       

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