alternative to mounting cv's in big bearings but same r

**yoshi** · 08-20-2006 08:43 AM

ok,..here's my idea, may work, may not but I figured i'd post it so someone can build it if they think it's doable...

left pic is a rear view looking from behind the carrier, right picture is a side view looking at the side of the carrier..

The red is the cv's, the blue is a bearing that is mounted between the cv's. The yellow is the flanges that the cv's attach to. A 4 inch sprocket will also attach to the side of one of the flanges, I forgot to draw it in the pic. The blue bearing slides over a coupler that has splines inside. One side of the coupler is welded to a yellow flange, the other flange has a little spline shaft to slide into the coupler to tie the cv's together. The green represents a good roller made of rubber, delerion, tephlon, I don't know, just something super tough that can take some pressure. There are 3 rollers, 1 on top, 2 on bottom. They keep the cv's from wobbeling but the spinning is done on the single bearing in the middle. The pink is a long pin that connects the rollers to one another and altho I didn't draw it, there are set screws above that you tighten to apply pressure to the cv's from the rollers.

The real trick would be to get the sprocket in the center and mount 2 bearings on either side. This puts all the load from the chain in the middle of the shaft. If it's too far to one cv, it will put alot of pressure on the top roller of that cv and alot of pressure on the bottom 2 rollers of the other cv.

You could have more rollers if you want and you can make thm as big as you'd like as well. I have a couple ideas for a case for it but I left it open for people to see. There could be abillet plate that runs down the middle, or some 1/4 or 3/8 plate on the sides, maybe even a housing to hide the rollers, lots of options. I might build it out of wood with the cv's I have in back to give a better picture..

This may work, may not, figured I'd share it though....

click on the pic so the colors are correct

**masterfabr** · 08-20-2006 09:09 AM

I've thought about that also. The problen I see is the package will be larger than can be accomodated and the small bearing size needed would not be of adequate strength. A single thin section roller brg w/ needle thrust would be much more compact.Skf will custom a thinsection roller bearing.I'm going to inquire if they will do a 105mm custom taperer roller monday.

**tenaja** · 08-20-2006 10:36 AM

I see two drawbacks. First, the outside of the CV joint becomes a bearing surface. That means wear.

Second, there is a lot less bearing surface in use. With a large bearing, you have continual contact around the CV, for a full 360* of support. Even if you use a dozen bearings, you still only have 12 contact points of support.

Oh, yeah...it's more complicated, too. Getting a large quantity of bearings lined up and snug on a CV joint is a lot harder than making one press-fit hole.

**yoshi** · 08-20-2006 10:50 AM

Originally Posted by tenaja

I see two drawbacks. First, the outside of the CV joint becomes a bearing surface. That means wear.

Second, there is a lot less bearing surface in use. With a large bearing, you have continual contact around the CV, for a full 360* of support. Even if you use a dozen bearings, you still only have 12 contact points of support.

Oh, yeah...it's more complicated, too. Getting a large quantity of bearings lined up and snug on a CV joint is a lot harder than making one press-fit hole.

I agree it's more work. The cv is a metal surface and the rollers would be a different material, they would eventually wear but they could be replaced. If the sprocket is centered between 2 bearings in the middle, there shouldn't be a whole lot of stress on the rollers as they are just a guide to keep it from putting side loads on the bearings. It will spin straight naturally if the sprocket is centered, would be more of an issue if the sprocket was offcenter.

I know it's a bit of work but I keep hearing these 1k prices for a set of 105 mm bearings and thought i'd give an idea that is a little more work, but alot cheaper. Just an idea, may or may not work but i'll never do anything with it, i'm hooked on u-joints now. I thought someone "might" be able to work out the bugs and run with it....

**masterfabr** · 08-20-2006 11:05 AM

DITTO!!!! tenaja! I must admit it's food for thought. Many ideas floating around is a VERY good thing.

**tenaja** · 08-20-2006 11:10 AM

I just thought of another issue. Since the CV joint is a bearing surface, you have to keep it clean. Imagine if you started grinding sand between the cv joint and the bearings. That would be very commonplace in the dunes, if you didn't seal it. Small rocks would be even more destructive.

**yoshi** · 08-20-2006 11:33 AM

Originally Posted by tenaja

I just thought of another issue. Since the CV joint is a bearing surface, you have to keep it clean. Imagine if you started grinding sand between the cv joint and the bearings. That would be very commonplace in the dunes, if you didn't seal it. Small rocks would be even more destructive.

Your not running the bearing on the cv, your running a bearing in a roller on the cv. It would be no different than a chain running across one of the big derron(sp?) bushings out there, but I agree rocks could get into it. I think it would divet the roller and not do much harm though, a rubber roller may be better since there is not alot of load pushing against the roller.....