Topic: Message #770608

[79coyotefrg]

 

We say that 2 u-joints are in-phase if they are fitted to yokes that are fixed on the same shaft, such that the 2 opposing bearing caps in the u-joint that are held captive by the yoke on the shaft (the inboard yoke's u-joint caps) are both in the same orientation.
   

A pic is worth a thousand words. Look at the pic to the left. In the top shaft, the 2 joints indicated by the green arrows (ignore the fact that the right-most is part of a double cardan CV assembly) are in-phase because in both joints, the bearing caps held captive in the shaft are both vertical, while the bearing caps that are free (not held captive in the shaft) are both horizontal. If you then look at the bottom shaft, you will notice that this is not the case with the joints indicated by the blue arrows. The left has captive bearing caps vertically oriented, while the right most joint has it's captive bearing caps oriented horizontally. The joints are therefore 90° out of phase.