Plastic that doesn't deform easily?

[Superslinky]

In my curent project I'm going to use two shoulder bolts 180 degrees from each other t'ing off the end of a shaft and twisting the face of the shoulder against the other end of the drive (think of it line a flat head screwdriver). The shoulder bolts will have some type of poly sleeve but I'm not sure what type of material to use for the sleeves. Does anyone have a suggestion as to a material that would be suitable? It needs to have minimum deflection and distortion yet rigid enough to withstand the torsional load.

Thanks

 

[MintJulep]

Maybe some sort of plastic.

 

[berkshire]

Have you considered a thermoset like reinforced phenolic resin?
B.E.

 

[flash3780]

Look into a material called Polyether ether ketone (PEEK).

 

[MikeHalloran]

Since not a single useful number has been provided that would allow us to suggest something on a scientific basis, why not start with something inexpensive, like Delrin, and let us know if that doesn't work out?



Mike Halloran
Pembroke Pines, FL, USA

 

[Superslinky]

In a nutshell what I have is an electric motor rated at 225hp and a torque rating 1300ft-lb. I have a drive shaft connected to it turning a differential gear (same setup as a car). The drive shaft has two u-joints, one at each end. The u-joints have to be electrically insulated with some type of material insulating it for up to 1800V yet have the mechanical properties to not break, or at least not break within a reasonable amount of time (to be determined what that time actually is).

 

[MintJulep]

Are you set on reinventing something that already exists?

There is no shortage of commercially available electrical insulating shaft couplings.

 

[Wrenchbender]

Without understanding the need for electrically insulating the U-bolts, try a composite, e.g., fiberglass reinforced phenolic. (Two annular tubes for the U-bolt legs, 2 phenolic washers, 2 metal washers, loctite the nuts.)?

 

[asimpson]

Any plastic will be way weaker than steel.

Ceramic fasteners are stronger but expensive.

Following are some leads:

http://www.craftechind.com/Index.html

http://www.igus.com

http://www.dynacer.com/Ceramic_Screws_Nuts_Washers.htm

A carbon fiber drive shaft might be best option.

 

[Superslinky]

I don't need to re-invent something here but the problem I've seen is that the package size and application of commercially available products don't match. I need to keep the design package within a 8.75" dia. x 1.75 length. In the end I'm basically building a coupling. One side will have a flanged mounted shaft hub (mounted to the drive) the other side will have a flange mounted U-Joint hub with the drive shaft mounted to that.

 

[moon161]

Bring in Dennis Anderson as a consultant. 1300 ft-lb is monster truck torque. Consider that my observed MTBF watching monster truck events is that about 20% of trucks present will fail in an event where they run full out about 60-90 sec, giving MTBF of 300-450 sec.

http://www.bigfoot4x4.com/frequent.html##21

 

[moon161]

Actually, 60-90 sec full out is pretty generous. Probably a 20% duty cycle on WOT at an event.

Dragster torque is reported at about 4500 ft-lb.

 

[ScottyUK]

Why insulate at the joint where all the stresses are highest? Can't you separate the insulated joint from the coupling?


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If we learn from our mistakes I'm getting a great education!