Flexible drive shafts 3

[sboyce]

I'm thinking about using a flexible drive shaft in a design, but I'm worried about backlash. I'm going to need to know the orientation of the end effector to a good degree of precision. It seems to me like such a shaft would have some pretty big backlash problems in such an application. I've never worked with them though so I don't really know. Am I wrong? Is there anything else I should be taking into consideration when working with flexible drive shafts?

-Sam Boyce
Asst. Mechanical Engineer

http://www.AppleAid.com

 

[unclesyd]

Here is one company that we have used extensively for flexible drives on production machinery. They should be able to help you with your problem.

http://www.elliottmfg.com/

 

[tlee123]

Sam,

I have never used flexible drive shafts. However, I remember reading that the torsional stiffness is very good if the shaft is straight or follows a simple arc (constant radius).

If the shaft has to form an S-shape, the stiffness suffers.

I can get the reference for this if you need it.

Tom

 

[MintJulep]

I don't see how a flexible shaft would affect the degree of precision you could achieve in any way.

Accuracy might suffer.

Do you only need to know where it is, or do you also need to control its location accurately? Encoder located at the effector end of the shaft would accomplish the former, encoder and brake the later.

 

[benta]

This site has some pretty good info.

http://www.suhner-transmission-expert.com/site/index.cfm/id_art/14496/vsprache/EN

Benta.

 

[strokersix]

Agree, Elliott Manufacturing is a great source for flexible shaft products. There are many variables (helix angle, wind direction, wire size, and more) to tweak in the shaft design to balance properties but basically, it'a a trade-off between bend flexibility and torsional stiffness.