Linear solenoid help

Discussion in 'General Electronics Chat' started by Pintea Mihaita, Nov 4, 2014.

  1. Pintea Mihaita

    Thread Starter New Member

    Nov 4, 2014
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    Hi all.
    First of all sorry if i posted in the wrong section.

    So I need a high speed linear solenoid (preferably a push and pull) that can push/pull a force of about 20Nm on a distance of 2.5-3cm, at 12VDC (even 24VDC could do, but i prefer the 12VDC option).

    One that only pulls would be OK too if push and pull are not available.

    Could any of you guys point me to such a solenoid?
    I found some on the internet but they are sold at a minimum of 500 pieces and I only need 1 or 2 max.

    Basically i need to move a leaver 2.5 cm in one direction, then a spring brings it back, and 2.5 cm in the other direction.
    The solenoid stays only about 0.5 sec active. But i does this many times (one every 5 sec maybe) when it is active.
    Thank you very much for your help.
     
  2. MaxHeadRoom

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  3. gerty

    AAC Fanatic!

    Aug 30, 2007
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    There are several different types of car door locks that fit your criteria, I would look into that, some may require an external spring return.
     
  4. JDT

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    Feb 12, 2009
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    The solenoid might be linear in travel but will be far from linear in force. They only generate high forces millimetres from the end of the travel. Further out the force quickly drops off. Never seen a push and pull solenoid.

    For linear forces and push and pull you need a "voice coil" - like loudspeakers have. I have a huge one of these that I got from a 1970s disk drive. About 4" travel, huge magnet!
     
  5. MaxHeadRoom

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    The bi-directional ones have a coil that is pulsed to neutralizes the P.M. magnetic end. once extended, it stays extended by means of a spring, to return to the P.M. end the coil pulse is reversed, it is then re-held by the magnetic force.
    Max..
     
  6. Pintea Mihaita

    Thread Starter New Member

    Nov 4, 2014
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    Thanks for the replies.
    I need it for a project I am working on to make my Kart shift gears by the means of the solenoid.
    I can use a only pull solenoid too. If any of you know where I could buy one that meets my criteria.

    The car doors one are to weak for me.
     
  7. MaxHeadRoom

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    Might be easier to make one to your specs?
    Max.
     
  8. Pintea Mihaita

    Thread Starter New Member

    Nov 4, 2014
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    Hmm I have zero experience is making a solenoid. Can I build one that is strong enough?
    Is it relatively easy?
     
  9. MaxHeadRoom

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    If you have a car door type, try it on 24vdc to see if it does the trick.
    You will essentially double the torque, if not quite up to it, design one based on it or re-wind it with larger gauge wire, = to higher current and less turns.
    Max.
     
  10. Bernard

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    Aug 7, 2008
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    You could use a model airplane servo, like All Electronics # DCS-107, $ 10.95, 85 oz in. With 1 in arm, 120 deg would be close to 2.5 cm & it is reversable. 120 deg in about .4 sec. Would need a simple controller, like a 555 & R's & C's. I used one to reset an air- soft target. Picture at Bernard, Photos.
     
    Last edited: Nov 4, 2014
  11. MaxHeadRoom

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    The OP says he need 20Nm that servo shows it as 25oz-in (.17Nm).
    Max.
     
  12. Bernard

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    My old book says a newton( N) = about 3.6 oz, or 20 N = 72 oz? Re checked # DCS-107, still 85 oz-in.
    Nm to me is torque not force. Either me or OP is confused.
     
  13. MaxHeadRoom

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    AFAIK there is a direct translation from N-m to Oz-in, I did err the servo was shown as = to 85 oz-in (0.6 N-m) ?
    Max.
     
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  14. Bernard

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    I did not think that the OP really meant Nm as he is looking for a force from a linear solenoid. More information is almost allways helpfull.
    Maybe a linear actuator would better describe need
     
  15. MaxHeadRoom

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    The way I interpret it torque is a moment of force around an axis, the OP seems to describe a lever which I would think would fit the bill, he needs an actuator to exert a certain force on a lever, just as the servo example does?
    Max.
     
  16. Pintea Mihaita

    Thread Starter New Member

    Nov 4, 2014
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    Yes. Exactly what max said. I will post a picture tomorrow so you can better understand what I need.
     
  17. Pintea Mihaita

    Thread Starter New Member

    Nov 4, 2014
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    So I drew a little sketch of what I need the solenoid to do.
    I also bought a hand held scale and measured the kg of force needed to move the leaver and the scale showed 16Kg. (see in the picture how i did it)
    Is there such a powerful solenoid that is also compact?
    Here is a link to the image.
    upload_2014-11-5_16-37-27.png
     
  18. MaxHeadRoom

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    You have to add the distance from centre to end of arm, 16k-?cm = xN-m.
    Max.
     
  19. Pintea Mihaita

    Thread Starter New Member

    Nov 4, 2014
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    The distance is 6 cm.
     
  20. MaxHeadRoom

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    According to my calc. 16kg and a moment arm of 6cm = 2666gram-centimetres = .2616 N-m.
    Max.
     
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