Is a double cardan driveshaft a true CV joint?

Patrick P.

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I'm not sure if the title explains what I am trying to figure out, but why is it that a double cardan driveshaft is sometimes referred to as a 'CV' driveshaft?

I was under the impression that a CV driveshaft was similar to the type of CV joint found on say an RCV axle or most modern day vehicles. You know, where it has the ball bearings and such.

Lastly, why is it that our driveshafts on these TJs don't use CV joints like an RCV axle or something? Wouldn't that be better than the double cardan driveshafts (which near as I can tell use u-joints)?
 
That would depend on your meaning of true cv joint? DC is CV shaft. But from what I can tell near constant velocity.

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A DCJ is a type of constant velocity joint but one must constrain the input and output shafts to have equal angles from the joint to maintain the near constant velocity.

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Yeah, but why don't they use a typical CV type joint like you'd find on an RCV axle or most modern vehicles?
 
Yeah, but why don't they use a typical CV type joint like you'd find on an RCV axle or most modern vehicles?
It is my understanding that space constraints and cost prohibit the size of CV that would survive the RPM requirements of a driveshaft. The driveshaft sees anywhere from 3-4 times the RPM of wheel speed and that exceeds the bearings ability to survive in a CV joint of that size.
 
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It is my understanding that space constraints and cost prohibit the size of CV that would survive the RPM requirements of a driveshaft. The driveshaft sees anywhere from 3-4 times the RPM of wheel speed and that exceeds the bearings ability to survive in a CV joint of that size.

Hmmm, it would be interesting to see what the size (and cost) of that type of driveshaft would be, assuming someone could do it.
 
Hmmm, it would be interesting to see what the size (and cost) of that type of driveshaft would be, assuming someone could do it.
Why? The ones in the JK don't last long at increased angles and the ones we typically use work for the vast majority of folks in most applications. Double Cardan driveshafts are not very problematic, relatively cheap, and pretty durable.
 
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Why? The ones in the JK don't last long at increased angles and the ones we typically use work for the vast majority of folks in most applications. Double Cardan driveshafts are not very problematic, relatively cheap, and pretty durable.

Just curious mostly, that's really all!
 
I think that pretty much explains it. When I hear 'CV joint' I think of a typical ball bearing style CV joint like you'd find in any modern day vehicle, not a double cardan driveshaft.