×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Bi stable belleville spring design

Bi stable belleville spring design

Bi stable belleville spring design

(OP)
There was a great thread a while back about this, and I was looking for some more help. I understand to get the bi stable effect i need a h/t of 2.82 or greater. I need a combined travel of .025" and am constrained to a diameter of .096. I need about 50 Grams of force at the top, and have about 150 grams of actuation force available. If I get the same travel up and down, then the h=.0125 and t= about .0046 I should get the bi stable action, What materials will put me in the range I need?

thanks for the help
Bryan

RE: Bi stable belleville spring design

Do you need the snap force to be equal from both sides or the 50 grams from one side and other force to snap it back?
This will have an influence on the h/t you need.
You are asking for a travel between both stable positions of 0.025" which is also influence the h/t greatly.
Adding all this and the very small OD of the spring you will need h/t so high and the thickness of spring to be very very small resulting in very very high stresses in the range of thousands of ksi (1 ksi = 1000 psi).

RE: Bi stable belleville spring design

(OP)
israelkk

I have about 150 grams of Driving force, I would like something close to 50 grams of holding force on one side. There is very little force needed in opposite position. The travel I need is .025" between stable positions. I have room to move on the 50 grams at the top 25 to 50? I kind of pulled the 50 out of the air. The critical design piece is the Travel, and force to drive from one side to the other. I am working on .01" centers but I could do layers if I need to to get more OD. the shape is another variable that I could work with, How does notching the inside and outside change the equations? (see attachment)
I really thank you for your help with this.
Bryan

RE: Bi stable belleville spring design

There is a product similar to the notching you offer called "Clover® Dome Spring Washers" but they all offered in the linear range and not for bi-stable applications. You can contact http://www.asraymond.com/Clover%C2%AE%20Dome%20Spr... and try to check if your requirements can be met but I still believe it is not possible.

I have know knowledge of any design formulation literature that deals with such springs as compared to the vast literature regarding belleville springs. Basically, those springs are three times more flexible than bellevile springs however, there is the issue of stresses too. The point I wanted to present in the previous post was that to my best experience and the theory of belleville springs you are climbing on a very high tree and you are in an charted area as long as the space for the belleville spring is so limited for the 0.025" travel no matter the forces.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources