"keystone" taper on clutch spline
"keystone" taper on clutch spline
(OP)
I am trying to specify a "keystone" taper on a cylindrical spline, i.e. to have the male and female splines be cylindrical in cross-section, but to have the tooth thickness on the male, and space width on the female, increase linearly along the axis. The application is a female selector which slides on an input shaft and can mate with male teeth on either a high- or low-speed gear. The "keystone" profile keeps the selector in positive engagement with the spline on the gear and prevents it from creeping or jumping out of engagement. I have seen pictorial representations in textbooks such as Nunney's "Light and Heavy Vehicle Technology". However, I am wondering is there a specification for this kind of spline or at least for the rate of taper? We have used crowned splines in the past but not this.





RE: "keystone" taper on clutch spline
Mike Halloran
Pembroke Pines, FL, USA
RE: "keystone" taper on clutch spline
RE: "keystone" taper on clutch spline
I've never seen anything quite like that in practice, so I'm not aware of a standard for it.
Mike Halloran
Pembroke Pines, FL, USA
RE: "keystone" taper on clutch spline
RE: "keystone" taper on clutch spline
I believe keystone or back tapered spline are standard on automotive manual transmissions. See attached.
http://files.engineering.com/getfile.aspx?folder=7...
RE: "keystone" taper on clutch spline
If you want a face-type coupling that provides better precision than the common dog ring clutch, you might consider a curvic coupling with teeth that have a negative pressure angle (around 2-4deg).
You could also apply some helix angle to your spline teeth to promote an axial force in one driving direction.
RE: "keystone" taper on clutch spline
tbuelna - unfortunately a helical arrangement is out because in reverse it will drive the clutch out of engagement. I think shear weakness of the keystone wouldn't be too much of a problem with adequate design, a minimal taper angle and coarse tooth pitch, but obviously this would be a part of the design process. We are, in fact, also thinking of curvic couplings with negative angle, as you suggest, which we have used elsewhere in the driveline, but this may raise space claim and also strength issues and might require a fairly substantial redesign.
RE: "keystone" taper on clutch spline
My Thoughts are.
How about an internal major dia slight press fit spline. AGMA class 4.
I agree with Terry keystone appears to be a nightmare to fabricate.
I believe the RPM's will be limited, in it's application.
all looks good on paper. how is your experience with these type of splines.
Mfgenggear
RE: "keystone" taper on clutch spline
https://youtu.be/2gAmFa0O3yY
RE: "keystone" taper on clutch spline
http://www.ezdries.net/Vidpics/4Runner%20Repair%20...
RE: "keystone" taper on clutch spline
RE: "keystone" taper on clutch spline