Have any sets ever made full use of the CV Joint...?

[Paul Boratko]

Talking about this part

There is a reason why it is frictionless and 1.5 studs inside... Have any sets actually made use of this in the last 13 years..?

[piterx]

ahah that's something i always wondered as well!

i had to cut a 3l axle into a 2.5 to avoid it from popping out...

[DrJB]

I think the reason it's long is so you can make a telescopic connection with a variable length. There are at least 2 instances where this could happen:

1. car suspension with non-vertical motion of the spindle.

2. Telescopic Connection between engine drive-shaft and front axle for articulated construction machines (wheel loaders) and large tractors (quad-tracks)

Edited April 11, 2014 by DrJB

[Paul Boratko]

I build a little monster truck/car last year and used the frictionless design of the CV joint to make my steering'suspension work along with the drive through the new ball joints(from the 9398/8110)

I was at work today and wondered if any of Lego's official sets used it in this way yet(with the in and out motion).. I don't have many of the sets that this part came in...

In a real car with front drive, the spindle going into the CV Joint slides in and out slightly when steered which is most likely why Lego designed the part this way in the first place...

I think the reason it's long is so you can make a telescopic connection with a variable length. There are at least 2 instances where this could happen:

1. car suspension with non-vertical motion of the spindle.

2. Telescopic Connection between engine drive-shaft and front axle for articulated construction machines (wheel loaders) and large tractors (quad-tracks)

Yeah, I know exactly what it is for and what it does, I wanted to know if any sets made use of it...

[DrJB]

No, I am not aware of any use in official Lego sets, of such feature. This is kind-of-like the old differential cage. You have the ability to add a clutch to make a diff-lock, but it was never demonstrated in an official lego set. I guess that is where AFOL engineers (mechanical) step in.

A bit more about #2 in my prior post. In the 8265 wheel loader, there are 3 cardans all aligned with the pivot point of the articulated chassis. Two of those were for the loader arm and bucket. The third was for connecting the front and rear differentials. In REAL wheel loaders, they do not put a cardan at the pivot point. Instead they put 2 CV joints one way behind the pivot, the other in front of it. The two CV joints are then connected with a telescopic drive-shaft. You can imagine that, as the chassis steers left/right, the distance between the two CV joints changes, hence the need for a telescopic connection of variable length. This is also better for the durability of the CV joints as they only turn through half of the steering angle of the chassis.

Edited April 11, 2014 by DrJB

[Paul Boratko]

I didn't think that any sets used it, but it is also in one of the new EV3 sets and I didn't know how it was used in that one... I also wasn't sure how it was used in the Unimog...

This was how I used it...

[jantjeuh]

Only 8110 I believe.

[Paul Boratko]

Only 8110 I believe.

Cool.. I was wondering if the axle actually slid back and forth into that CV joint when the suspension was compressed evenly downward.. My wife built it, but unfortunately it has been taken apart and I can't get a look at it anymore.... I do remember something being a bit odd about the way the front suspension worked... Can't remember what it was though...

Edited April 11, 2014 by Paul Boratko

[darsedz]

F1 car (42000) on rear axle use them

[skppo]

One use is making diagonal driveshafts that aren't exaclty pythagorean in their lenght. I think the 8110 pto driveshafts are like this?

Edited April 11, 2014 by skppo

[Paul Boratko]

F1 car (42000) on rear axle use them

The axle doesn't actually slide in and out of the CV Joint though does it..? It is always stationary I thought..?

Edited April 11, 2014 by Paul Boratko

[Phoxtane]

It could also be that way because there's no good way to remove an axle from the piece. It's really smooth, and feels slippery as a result.

[Freekysch]

42006 uses 2 of them if i remember correctly.

[Paul Boratko]

It could also be that way because there's no good way to remove an axle from the piece. It's really smooth, and feels slippery as a result.

That is a really great point..

But why the need for it to be 1.5 studs deep though if the intention was easier axle removal..? It could have been 1 stud deep like a universal joint or a typical axle connector and still worked fine... Or maybe they are just giving that option to get that part to work in different situations that require various lengths..?

I was always under the assumption that it was frictionless to accept limited axle movement if needed lke a real CV Joint...

I actually have 4 CV Joints that have friction in them like any other connector.. I am assuming that they are design flaws though...

Edited April 11, 2014 by Paul Boratko

[N-4K0]

42006 uses 2 of them if i remember correctly.

Yes, but stationary.

[Meatman]

Paul, I have the Unimog and I don't see the axle moving inside of the joint used for the steering when the suspension is pushed downwards. Maybe it does move a tiny bit, but I do not see it.

[dhc6twinotter]

The CV used for the Unimog steering is the only one I can think of, but I've never actually looked to see if the axle moves within the CV housing. With the geometry of the steering shaft and suspension set up like it is, I would think there is some movement, but I'm not sure.

[DrJB]

Makes me want to rebuild the 8110 and find out ...

[rm8]

Makes me want to rebuild the 8110 and find out ...

Cv slides at 8110, because of axle geometry. I even dont need to test it (my 8110 is on the shelf near me) because Rotating point is at the ball joint. So if it is not multilnk with parallel links, it is imposible to connect axle with chassis without sliding joints.

Edited April 12, 2014 by rm8

[MrNumbskull13]

Cv slides at 8110, because of axle geometry. I even dont need to test it (my 8110 is on the shelf near me) because Rotating point is at the ball joint. So if it is not multilnk with parallel links, it is imposible to connect axle with chassis without sliding joints.

The links don't always have to be parallel... I have made a 4 link set up before and not a single link was parallel to another, the driveline wasn't parallel to anything either but I still found a position where I didn't need a telescopic driveshaft and the suspension still moved fine. It's hard to find these positions but it takes experimenting and it is possible.

[jantjeuh]

Cv slides at 8110, because of axle geometry. I even dont need to test it (my 8110 is on the shelf near me) because Rotating point is at the ball joint. So if it is not multilnk with parallel links, it is imposible to connect axle with chassis without sliding joints.

Exactly.

[Lipko]

The links don't always have to be parallel... I have made a 4 link set up before and not a single link was parallel to another, the driveline wasn't parallel to anything either but I still found a position where I didn't need a telescopic driveshaft and the suspension still moved fine. It's hard to find these positions but it takes experimenting and it is possible.

Probably it's due to the slack in the U-joints.

[Brick_Sticker]

As mentioned, the 42006 uses them, and they do function as sliding couplings. I know because I robbed them to use for another model and replaced them with u-joints, and had problems with the axles binding. I had to go to the next shorter size axle which was barely secure in each end of the joints to get things to work properly.

Brick_Sticker