unjoint, DC and driveline angle threads and links for the noobs? (1 Viewer)

[landcruiser3DP]

i’ve researched the faq and the forum as best i can (particularly on caster correction). there is also one great video out there (that i half understand) where a guy uses a playing card to explain ujoint angles and relative rotation speed (or something).
any good links if i wanted to make sure i understand these topics?
for instance what is this illustration trying to show?

 

[bhsdriller]

Just showing as the driveline angle gets further away from in-line the worse it is

 

[landcruiser3DP]

Just showing as the driveline angle gets further away from in-line the worse it is

thanks man.
i actually had to study it a bit. we are looking at the angular relation between the yokes or the splines or whatever on the “other side” of the u joints?
and “in-line” implies literally in a line? or in a line or parallel?
also, i never really totally got” what u joints do or why this in line issue is an issue. it’s that the relative speed changes if they are out of line?
also is there an “input shaft” and and “output shaft” shown here?
also, what is meant by “out of phase” or “in phase” please?

 

[Rwhat]

look at the picture you posted. Imagine how a U joint would bind if they were run like that. Like if the DL’s in the picture were cycled up and down while rotating at a very low speed. That’s were phase comes in. Imagine if they were offset 90*. Technically no binding if the DL angle is within range. That’s my interpretation of Phase.

 

[JeepinPete]

That image is alright, except for the last image. If the angles are the same, that is an acceptable configuration.

 

[JeepinPete]

U joints do not move at a constant speed when there is any angle between the input/output shaft and the driveshaft. They are accelerating and decelerating as the driveshaft rotates. This acceleration/deceleration creates a force ( force = mass times acceleration ). The smaller than angle, the less force is induced into the drivetrain. In order to eliminate the force, the u joints are set up at the same angles, and in phase. The forces cancel each other out.

When the angles are not equal, or the u joints are not in phase, the forces that the u joints are creating do not balance out. This is what causes the vibrations.

Double cardan joints work the same way, except they are designed to guarantee that the u joint angles are identical. So the forces are balanced at the double cardan joint. This requires that the u joint on the other end not be operated at the angle, otherwise it will create forces that cannot be canceled out. This is why the pinion has to be in line with the driveshaft with this type of driveshaft.

 

[landcruiser3DP]

U joints do not move at a constant speed when there is any angle between the input/output shaft and the driveshaft. They are accelerating and decelerating as the driveshaft rotates. This acceleration/deceleration creates a force ( force = mass times acceleration ). The smaller than angle, the less force is induced into the drivetrain. In order to eliminate the force, the u joints are set up at the same angles, and in phase. The forces cancel each other out.

When the angles are not equal, or the u joints are not in phase, the forces that the u joints are creating do not balance out. This is what causes the vibrations.

Double cardan joints work the same way, except they are designed to guarantee that the u joint angles are identical. So the forces are balanced at the double cardan joint. This requires that the u joint on the other end not be operated at the angle, otherwise it will create forces that cannot be canceled out. This is why the pinion has to be in line with the driveshaft with this type of driveshaft.

NICE. i have to kind of baby step my way though these things. which direction does the shaft turn in drive - relative to - well looking toward the front i guess?
i’m getting a bit off topic but it is then transferred to the rear diff? and this angular rotation gets transferred perpendicular so that the rear axle rotates forward.
so i guess the shaft turns clockwise and there is a worm drive in the rear diff that turns the rear axle forward?

 

[-Spike-]

That image is alright, except for the last image. If the angles are the same, that is an acceptable configuration.

Correct, with the exception that the yokes* joints** yokes should be assembled* oriented out of phase, instead of in-phase as depicted. This is how the front driveshaft is oriented from the factory on the 80 series.

*Edited because I just woke up.
**and fixed again because I was right the first time

 

[landcruiser3DP]

U joints do not move at a constant speed when there is any angle between the input/output shaft and the driveshaft. They are accelerating and decelerating as the driveshaft rotates. This acceleration/deceleration creates a force ( force = mass times acceleration ). The smaller than angle, the less force is induced into the drivetrain. In order to eliminate the force, the u joints are set up at the same angles, and in phase. The forces cancel each other out.

When the angles are not equal, or the u joints are not in phase, the forces that the u joints are creating do not balance out. This is what causes the vibrations.

Double cardan joints work the same way, except they are designed to guarantee that the u joint angles are identical. So the forces are balanced at the double cardan joint. This requires that the u joint on the other end not be operated at the angle, otherwise it will create forces that cannot be canceled out. This is why the pinion has to be in line with the driveshaft with this type of driveshaft.

thanks. sorry i am in like remedial class.
there are two C shaped parts in a U joint connected by a cross shape. so this geometric configuration lets each C rotate relative to the other one - well because there are two pairs of “pin connections”?
does “in phase” imply strictly that they not have any “angular deviance” relative to each other? or was there also an issue as to - well angular deviance i guess could have two meanings.
i mean so the C’s need to be “paired up” in some way would be one issue. then the other is whether they are “in line” and the output (?) and input shafts (?) are either literally in line or parallel?

 

[landcruiser3DP]

Correct, with the exception that the yokes should be assembled out of phase, instead of in-phase as depicted. This is how the front driveshaft is oriented from the factory on the 80 series.

man. spike. this issue is confusing.
the two inner C shapes of each ujoint are “in phase” in this diagram since they “line up” in the sense they are back to back (or front to front or whatever)?
and in late 80’s the front driveshaft should be out of phase? or what exactly?
also what is meant by “balancing a driveshaft” please?

 

[Rwhat]

Balancing a drive shaft is like a tire balance. To Eliminate vibration due to irregularities in weight after production Of the driveshaft.

 

[landcruiser3DP]

also. do i call the whole assembly here the u joint?

 

[landcruiser3DP]

Balancing a drive shaft is like a tire balance. To Eliminate vibration due to irregularities in weight after production Of the driveshaft.

thanks man? are they milling material off of it?

 

[KennyBob]

thanks man? are they milling material off of it?

I believe they are balanced similarly to a tire/wheel by adding weight.

 

[Box Rocket]

also. do i call the whole assembly here the u joint?

View attachment 2457589

This part is the ujoint. The parts that hold the joint are the yokes.
Untitled by Adam Tolman, on Flickr

 

[Rwhat]

thanks man? are they milling material off of it?

it’s usually a weight welded on the shaft. Looks like a curved washer.

 

[JeepinPete]

thanks. sorry i am in like remedial class.
there are two C shaped parts in a U joint connected by a cross shape. so this geometric configuration lets each C rotate relative to the other one - well because there are two pairs of “pin connections”?
does “in phase” imply strictly that they not have any “angular deviance” relative to each other? or was there also an issue as to - well angular deviance i guess could have two meanings.
i mean so the C’s need to be “paired up” in some way would be one issue. then the other is whether they are “in line” and the output (?) and input shafts (?) are either literally in line or parallel?

Phase is the angular orientation of the C's of the driveshaft itself. If there were no slip yoke on the driveshaft (ie yokes on both ends were welded), you would not be able to change this. Since the driveshaft has a splined slip yoke, it is possible to assembly the slip yoke out of angular alignment with the welded yoke on the other end of the driveshaft.

 

[SpenserAK]

Simple way to “get” what a single ujoint does is play around with a ujoint adapter on a driver, with a straight extension (the “driveshaft”) attached. Not sure how this forum regards Chrisfix, but his ujoint video shows it well, just after 2:00




First image is if there were no joint (thus your suspension could not cycle up/down) and second is with a joint.

Jeepinpete’s explanation is detailed and well-put. When angled, the rotational speed of the joint varies (sometimes faster, sometimes slower) as it makes a rotation, so if the joints at each end are at different angles (or out of phase) you get a vibration because they conflict with each other - such as, one may be trying to rotate faster while the other tries to rotate slower, thus you can imagine there’s an unwanted force being put through the assembly, which manifests as a vibration. With both joints at the same angle and phased properly, the variance of one is cancelled out by the equal variance of the other, and thus no vibration... both speed up together, both slow down together

 

[devo]

Correct, with the exception that the yokes joints should be assembled oriented out of phase, instead of in-phase as depicted. This is how the front driveshaft is oriented from the factory on the 80 series.

*Edited because I just woke up.

Interesting, what your saying here.
I staked slip joint side joint on my front DS on my 80 before taking it to the drive line shop for joints and a balance after 280K miles. They told me it was out of phase, I said it has been in that phase for 280K miles. They insisted it was out of phase and when I got it back they had put it “in phase“.

Now I have a drive line vibration?

Thanks for this info.



devo

 

[devo]

@landcruiser3DP

did you ever get your front DS dents sorted out?



devo