Drive Shaft Phasing Question

[xpehbam]

This is a motorcycle drive shaft. The output from the gear box has a sliding spline/rubber "doughnut" flex coupler; the opposite end of the drive shaft (input to the final drive) has a single cardan which is wedge pinned to the pinion gear of the final drive.

The flex coupler consists of a fixed "yoke" out of the gear box which mates to a rubber puck (doughnut) coupler, with another splined yoke (90 degree's to the first) on the aft side of the "doughnut". The forward tip of the drive shaft is splined and slides into the aft yoke. The horizontal alignment of the drive shaft between the output of the gear box and the input of the final drive is less than 5 degrees.

Can anyone tell me if this type of drive shaft arrangement must have "phasing" between the flex coupler and the U-joint at the final drive?

Thanks,

Bill G.

 

[Philrock]

It sounds like the rubber coupling is set up more-or-less like a cardan joint. If this is the case, it would be a good idea to have the 2 pins on the intermediate shaft parallel to each other, as is standard practice on a shaft with 2 cardan joints.

 

[sameaton]

you'd better do that. otherwise the clearance change after you re-assemble the coupler will have some influence to the whole shaft dynamic balance.