what stops the axle-end of the birfield from spinning in the cup?

[erics_bruisers]

I was thinking about this the other night and couldn't figure it out -- this was after 12 hours of work on a Sunday, and after 5 hours of subsequent driving for puppy placements --

-- BUT, if you have the diff spinning the inner axle, which goes to the birfield inner cup, which then transfers the force to the cage and the ball bearings, why doesn't it spin in the cup, all lubed-up, instead of driving the wheel, as we all know it does??

If this isn't technical enough, please move it to the same section the McGuire's waxing post went --

e

 

[Doc]

Um- I have the same question- but couldn't find a way to write it that didn't sound stupid.

How does the power get transfered to the wheels, and not lost in the bearings?

 

[cruiserdan]

.
.
.
.
.
.
.
.
.
.
.
Drive flange?

 

[erics_bruisers]

the drive flange is connected to the wheel though -- so what if that has more resistance sitting on the ground than the axle does spinning?

pretend i'm your kid and you want to help me --

e

 

[cruiserdan]

pretend i'm your kid and you want to help me --

e

 

[reffug]

C'mon Dan........... ........................dogs at your place your probably twins..................

 

[Beowulf]

Eric,

Here is a diagram so we're all using the same terminology. The inner axle shaft mates with the splines in the "star." The Star can swivel but it cannot rotate inside the tulip because the balls (being held inside the cage) will not allow the star to spin inside the tulip.

(Thanks to Raventai for sharing his birfield pic.)

-B-

 

[landtank]

The drive from the inner shaft to the out cage is by the balls. The balls sit in two U shaped channels that are perpendicular to the rotation. So while the balls will more along the channels to allow the joint to bend they will jamb on the sides of the channels to transfer drive.

Hope this helps

 

[landtank]

Well I was typing while you posted that -B- and I'm not changing my terminology

 

[Beowulf]

A picture is worth a thousand words. In the above example, a picture was better than 20 misspelled words.

Funny that the only common terminology is "balls."

-B-

 

[erics_bruisers]

this is good stuff -- THANK YOU -- who'd have thought the balls were stationary --

--

-- also, when the vehicle is severely angled (ie, the wheel is either very below or above the inner axle plane) and the axle stub (drive flange) is angled with the wheel, doesn't that angling acually tilt the wheel, so it's not sitting flat, but instead is tilteed outwards (if higher) or inwards (if lower)?? Doesn't this place a lot of strain on the drive stub / birfield?

eric

 

[reffug]

Well I was typing while you posted that -B- and I'm not changing my terminology

Oh so SENSITIVE........

 

[landtank]

If any of my words are mispelt it's not my fault we don't have a spell check on here. So until that day you'll have to guess as to what I mean.

 

[Beowulf]

>> So until that day you'll have to guess as to what I mean. <<

If we can decipher fAvE's posts then your spelling is no problem.

Doesn't this place a lot of strain on the drive stub / birfield?

Yes, but the joint is designed for this so it's not a big deal. The only time you should be concerned is after you've mounted 40" tyres, crawled up into the rocks, locked the front axle, turned the wheels all the way to the right, put the truck in reverse, and floor the accelerator. Then, you're asking for fireworks.

-B-

 

[reffug]

OK you truly are insane. Or you wheel with Junk.

 

[robbie]

or lead foot christo in the short bus. robbie

 

[cruiserdan]

It's not an 80 series birf.

 

[Rich]

It's not an 80 series birf.

Now I see!