CV Joint (coupling) Question 5

[goodguy1405]

I am researching max possible torque for a design for a cv joint. My question is: There are ball groove type with splines and just ball groove designs. Which design would produce the most torque? If there is anything you need to know more just ask. Thank you for responding in advanced.

 

[Tmoose]

Do you want the spline to be able accommodate "plunge' motion? Some CV joints do that by themselves. Plain Splines don;t like to slide when transmitting torque.

http://www.rowlandcompany.com/pdf/gkn-driveline-constant-velocity-driveshafts.pdf

 

[MikeHalloran]

Pick the big one.


Mike Halloran
Pembroke Pines, FL, USA

 

[rb1957]

the maximum possible torque on an (undefined) CV joint is ... undefinable.

another day in paradise, or is paradise one day closer ?

 

[goodguy1405]

LOL. I see I need to be more specific. Under google patents for constant velocity joint there are different variations of designs. There are designs with a spline and ball groove combo and some with just the ball groove design no spline. I believe a bigger cross sectional area provides more torque to a cv shaft but where does the spline fit into that as far as torque goes? Thanks.

 

[MintJulep]

A more typical design approach (assuming that you are not designing the joint itself) would be identify the torque that you need to transmit and select a suitable CV joint. If in fact you actually need a CV joint.

 

[LittleInch]

Cv joints don't produce torque, they transmit it.

Most CV joints I know don't allow axial movement, hence if you need axial movement you need splines and if you don't then don't have them.

Rather vague question I'm afraid.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[MikeHalloran]

As Tmoose alluded, most suspension designs don't maintain a constant distance between the articulation centers over the range of suspension travel, so half-shafts must use splines, or use a type of CV joint that also serves as a spline.

Tmoose also pointed out that plain splines don't like to slide under load, so ball splines are sometimes used.

There are other ways to deal with the changing shaft length problem. Later Corvairs and many Corvettes omitted a lateral link, so that the half-shaft itself acted as its own lateral link. AFAIK, no one has done that with a CV joint, only Cardan joints, because Cardan joints can carry a substantial axial load, and most CV joints cannot.



Mike Halloran
Pembroke Pines, FL, USA

 

[goodguy1405]

Thanks for all the help. Sorry so vague, on topic, have to be discreet on certain things.

 

[Tmoose]

"Most CV joints I know don't allow axial movement, hence if you need axial movement you need splines."

I believe the inboard end of FWD car driveshafts often use "tripod" CV joints that can accept over an inch of "plunge"/axial motion.

 

[GregLocock]

You can also get modified Rzeppa (6 ball type) CV joints that allow some plunge, at a cost in articulation angle and volume. A spline is pretty useless for plunging as it'll lock up under any significant torque. If you talk to a manufacturer they will give you an articulation diagram, showing the allowable combinations of plunge and articulation.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[gruntguru]

Rzeppa joints usually incorporate a spline for assembly purposes only. This spline does not allow plunge during operation.

je suis charlie

 

[kozlok]

If you want to contact me offline, I may be able to more fully answer your questions.

 

[FMTim]

If you have higher torque loads and lower speeds you might look into agricultural CV joints instead of the automotive ones. See Weasler or walterscheid.
If you are talking about the spline that transmits torque to the CV then, more surface area means more strength, but it is harder to slide.

 

[Cockroach]

Google Rzeppa Joint. I have very good success reverse engineering one for use in drilling applications, oilfield, Western Canada.

Regards,
Cockroach