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Old 10-30-2009, 09:09 PM   #10 (permalink)
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Quote:
Originally Posted by micondie View Post
The binding of a universal joint occurs at extreme angles ( like in an off-raod vehicle's driveshaft or front wheel drive axles) which is why CV joints are used in such applications. A CV joint has more bearing surfaces than a simple u-joint which usually means more friction. Does anyone have any data to support/refute this?
It depends on the type of CV joint. There are triangulated CV joints, then there are the types that you normally find in sets of impact tools as well, and a few other types beyond those that I've only seen on paper.

The CV type that you normally find on cars is the triangulated one. It has three bearings that have X surface area, which actually appears to be similar, if not slightly less, contacted surface area than the needle bearings in U-joints of comparable sizes.

The CV type that is commonly used in impact tool sets (wobble adapter) is just a ball in socket design with an arm or 3 that extends from the socket into the ball. The ball is slotted to allow it to move freely over those arms, while still being able to make every movement that a ball should be able to make without binding. Those setups are seldom good for more than about 45* of usable angle, though, where U-joints can function at a higher angle, but seldom last very long when made to.

The bearing contacted surface for the ball in socket design is less than that of the U-joint or the triangulated CV joint for a similar sized piece.
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