Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: edwardking on July 24, 2007, 09:33:17 AM

Title: CV (Constant Velocity) Joints
Post by: edwardking on July 24, 2007, 09:33:17 AM
Hi!

Does anyone know of a company that sells small scale constant velocity joints? I.E ones that arent quite as big as car ones, but are big enough and strong enough to cope with torque generated at a shoulder joint?

EK
Title: Re: CV (Constant Velocity) Joints
Post by: brijesh on July 24, 2007, 11:05:57 AM
All Hobby grade RC cars have CV joints. Walk into any hobby shop you will have tons of options.
Better yet vist towerhobbies...

http://www2.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=+&FVSEARCH=CV+Drive+shaft&search=Go

I tried "CV drive shaft" as search term. Try other terms.

Brijesh
Title: Re: CV (Constant Velocity) Joints
Post by: edwardking on July 27, 2007, 07:28:42 PM
Brijesh,

thanks for that, but Im looking for something meatier than R/C car CV's. I have Bosch GPA's for each shoulder rotation DOF (but linear actuators for the shoulder swivel) so the CV's need to be able to handle a fair amount of torque. Something inbetween R/C car cv's and small car Cv's. This is why my searches havent thrown anything up yet because I suspect that they'll be rare if not custom builds.

 :(

EK
Title: Re: CV (Constant Velocity) Joints
Post by: ed1380 on July 28, 2007, 02:58:17 AM
maybe go kart cv's. sry don't know where to get them
Title: Re: CV (Constant Velocity) Joints
Post by: edwardking on July 30, 2007, 12:57:14 PM
Ahhh...I thought that Go-Karts didnt use CV joints, but those mini dune buggy things do and they're definately smaller than most car ones. I'll try to find out who makes them and see if they will do.

Thanks for the idea!

EK
Title: Re: CV (Constant Velocity) Joints
Post by: Steve Joblin on July 30, 2007, 01:17:12 PM
Hmmm... automobile CV's are too big, RC Car CV's are too small... how about CV joints used in All Terain Vehicles?  Check out http://www.bigbuckatvproducts.com/Big%20Buck%20Driveline/Big%20Buck%20ATV%20drive%20line%20menu.htm for a nice selection.
Title: Re: CV (Constant Velocity) Joints
Post by: edwardking on August 04, 2007, 06:44:11 PM
Steve,

yup. Those are the things I was talking about. They look ideal, but Im going to contact them and get the specs.

i know it sounds as if Im being fussy, but i simply dont have the room for automobile CV joints for two reasons:

1) Diameter of the shoulder space at the shoulder exit point is just too small (and making it larger than it already is would be a bad idea)
2) the distance between the motor drive and the shoulder exit point is less than the minimum distance required for most automobile CV's to function correctly.

Even if the bigbuck CV's turn out to be ideal, Im still going to have to have the shafts custom built because all the shafts that are available with CV's are either an arbitrary length or specific to a particular vehicle (as one would expect). I can live with having a few shafts custom made though!  :)

Thanks for the link, greatly appreciated although Im not sure why it didnt come up when I searched for it?!

Edward