torsion bar hex mounting area

[whatif]

Hi,
I’m currently working on a design for a mount that holds a torsion bar spring from turning. The torsion bar has ends that are hexagonal in shape similar to a regular hex head bolt. I’m running into trouble trying to calculate how much surface area I should have in relation to the torque that will be applied to the spring, also the thickness of material at the corners.
Any ideas on how to calculate the size of the hex end?
Thanks
Darryl

 

[GregLocock]

Check out the front suspension on the older Ford Explorer or any number of Japanese 4wd trucks. Consider the state of the hex and the socket after some use.

It really depends on your application. If some burring is acceptable then you are really limited by the material properties of the socket.

On the other hand we designed a torsion spring for an application where ride height was critical. We went through the calculations, examined a few cars, and decided that the only way of getting acceptable control was to add an active ride height adjustment. So we canned it.

An interesting alternative would be to use a tapered conical socket (ie a Morse taper). Good luck







Cheers

Greg Locock

 

[whatif]

The design criteria to use a hex torsion bar is written in stone. So I have to come up with something. Thanks

 

[apropos]

This company was spun off by Rockwell International in 1997. They are a major manufacturer of automotive springs and suspension parts. Good luck

http://www.arvinmeritor.com/products/carproducts/mssctorsionbars.asp