Taylor-race upright beairngs

[Blake]

Does anyone know what kind of bearins they are and if they can take the thrust of the hub wanting to push and pull and the drive line. Also how are you guys solving this problem if this bearing wont handle it? Tapered bearings?

[Blake]

Does anyone know what kind of bearins they are and if they can take the thrust of the hub wanting to push and pull and the drive line. Also how are you guys solving this problem if this bearing wont handle it? Tapered bearings?

[KU_Racing]

not quite sure what you are asking- but if the taylor setup didnt work, 60% or more of the teams wouldnt use it.
we dont use the taylor race setup ($) we build our own. each upright has 2 roller bearings inside to handle vertical loads, and a thrust bearing on the inside and outside to handle horizontal loading.

[kwancho]

Do really 60% of the teams use the Taylor Race setup?

[Jersey Tom]

They are double row angular contact ball bearings, and handle both radial and thrust loading. LOTS of radial and thrust loading.

Kinda big and heavy though, so we're no longer using them. We'll see if our alternative works.

[KU_Racing]

to my knowledge, a huge majority of teams use the taylor setup.

tom, what are your alternatives? I am trying to redesign our uprights, since our previous bearings sucked.

[Garlic]

Where did you obtain this knowledge?

Maybe 60% of teams have some sort of purchased part from Taylor Race, like stub shafts, tripods, etc. But there's no way even close to 20% use the entire setup. There are well over 200 teams...

[Jersey Tom]

I'd say a good percentage run Taylor bearings in the rear, since many teams use their 34mm OD drive flanges, and conveniently Taylor sells 34mm ID wheel bearings, while many large bearing manufacturers sell them in increments of 5mm, ie 20, 25, 30, 35...

[Garlic]

The 'taylor race setup' includes a differential housing, which I've only seen a couple times at comp in the last 5 years.

[Scotty]

I wish I could say 100 % ..but I know allot of you guys make your own stuff.I have never really even checked to see what the percentage is. I can say that I do appreciate all the teams I work with and enjoy the challenges you guys throw my way. And look forward to meeting the teams every year. The upright bearings that we use for our system ..64mm x 34mm x 37mm is a double row bearing and are the same bearings you find in some of the DSR cars. They could be classified as too big in some cases but they can defiantly handle allot.

[KU_Racing]

when i said 'Taylor Race Setup' I was referring to their tripods and drive shafts. Frankly I wish we could use the whole system, but its just too expensive. I do like taylor though- they make good stuff. A buddy of mine is related to Craig Taylor, so I got to meet them at PRI last year- a bunch of very nice people.

[Storbeck]

I'm interested in how people size these double row bearings. They are of course have ratings for the radial and axial load, but the limiting factor for us is the moment load due to cornering. So with regular bearings that are spaced out you can get equal and opposite radial loads up and down to take the moment, but it seams like with the close spacing of a double row bearing it would be more like two equal and opposite axial loads; one on the top of one race and one on the bottom of the other race. Actually some combination of axial and radial. Since the axial load is not evenly distributed around the race of the bearing, like a normal axial load, it's hard to say how this should be done.

I tried to basically take the forces at the two races and resolve them into axial and normal loads, but there is still the problem that the axial load the bearing is rated for is distributed around the race evenly, and the one I calculated isn't, so the load rating should be what? Half at most, probably a little less than that?

It appears to me that Lee Stohr uses the taylor race setup on his DSR with about 1000lbs and a bunch of downforce, and advertises it as "Large wheel bearings are used to take the high downforce..." they must be WAY oversized for our cars.

[Marshall Grice]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">So with regular bearings that are spaced out you can get equal and opposite radial loads up and down to take the moment, but it seams like with the close spacing of a double row bearing it would be more like two equal and opposite axial loads; one on the top of one race and one on the bottom of the other race. </div></BLOCKQUOTE>

the axial preload on the bearing should be large enough to take care of the unevenly loaded axial forces.

[Analogue]

The proper way to do moment calcs is to break up the moment into the radial and axial components.

There's a catch. With two ball bearings, when the inner and outer races are displaced axially they become an angular contact bearing. Two deep groove ball bearings can be too heavily loaded from a lateral tire load, but displacing the inner races inward changes the contact angle and can make it ok.

Contact angle is about impossible to calculate (manufacturing tolerances), and very difficult to measure (measuring stiffness in both directions is the only method I know). The contact angle depends on bearing clearance, race displacement, load, etc. For that reason, our team uses angular contact cartridges. These are match ground such that the contact angle is fairly well known. It's too easy to mess up the machining of spacers to get ball bearings far enough apart.

Teams do get ball bearings to work with and without spacers, but in my opinion, this is poor design.

Taylor race kit uses bearings from a 1980-1984 VW Rabbit. There are also other matching VW applications, I think Jetta and Scirocco.

By the way, avoid the Timken bearings, they have the same outside dimensions but are tapered rollers and the seal drags heavily. SKF and FAG make some nice low drag sealed ones. The SKF is potentially too low drag; we had one leak in endurance and almost got pulled.

Keith

[Richard Pare]

Using 2 deep groove bearings is very common on lower formula race cars - all that is necessary in selection is to make sure that it can take the lateral loading, with the limit being around 10-12% of the radial load capability. 2 6010 bearings will handle the loads on the rear of an Atlantic no problem - on an FF they will last forever. You obviously don't need that large a bearing, but that example can be used to steer you in the right direction.

In assembly, the "trick" is to make sure that you do not put any preload on them - preloading will kill them real quick! Make the inner race spacer (hardened) about .010 longer than the distance between the shoulders for the outer races, and use stout, flat plates that contact both inner and outer races when pressing the bearing into the upright - assembly this way will assure that you do not add any preload inadvertently. NEVER let the press load go across the balls!

If you use the angular contact cartridge bearings (the Rabbit, Dasher, etc, bearings), be careful which ones you use. All of the current SKF units are made in Brazil, and on a Formula Ford front will last on 20 minute session before you lose the preload. Real junk. Stick with the FAG, IF you can find a dealer that can get them. However, some of the newest FAG units are also made in Brazil, so make sure you get the ones made in France, Canada, Germany, Spain, or Italy. Also, what you are buying are made to be OEM replacement bearings, and FAG sizes the outer diameter .002" larger than nominal, as they expect that the used housing that they would normally be pressed into (street cars) will have stretched that much. You can either grind or lathe cut them to the proper dia, or just make the bearing bore .002" larger.

[Analogue]

I disagree on a few points. The max thrust loading for a deep groove bearing isn't that bad. If not explicitly stated by the manufacturer, max axial load should be close to max radial load.

Preload is a wonderful thing, if not abused. Preload can be used to increase the effective spacing of two bearings. Pinching the inner races in relative to the outer races will turn two ball bearigns into back to back angular contact bearings, and will increase moment stiffness greatly. Using a longer inside spacer will create a front to front setup if the outer races are fixed, and will have little moment stiffness. If the outer races are unclamped and dependent on frictio to stay put, you will never get the preload you desire. Also, you will never get the zero preload some may desire. Only one of the bearings can effectively take thrust. Preload can shift it to one or the other, but there's no free lunch. Sharing the load between both bearings is laughable, unless there is enough compliance in the system to elastically average the forces on the bearings.

Preload is hard to set. You need to find the right force to displace the balls in such a way that the contact angle handles the combination of radial and axial loading. Unless the races are match ground, you are basically screwed.

And yes, never ever ever push on a bearing through the balls. Also, don't drop a bearing. Both mistakes are guaranteed to brinell the race.

I will reemphasize, due to the difficulty of setting preload properly, I would not use deep groove ball bearings for wheel bearings. They just aren't the right device for the job. They have plenty of other uses on the car, just not ones needing moment stiffness. I said in a previous post you can get away with it, but only with bearings that are oversized.

That's good info on the SKF and FAG units. I'll check to see what we have. We were definitely disppointed with the amount of slop in the SKF units, but it seemed that we never lost preload-they initially had no preload to lose.

0.002" inch is a lot. I remember checking some FAG bearings earlier this year that were right on spec. I would never turn one on a lathe. The surface finish is guaranteed to be poor compared to grinding. Poor finishes will lead to losing press fits very quickly. There's some good info in bearing handbooks about the importance of surface finish.

In short, no matter how hard you try, one of your bearings will end up in a world of pain, while the other does nothing. If you have one bearing that can take both the radial and axial loadings by itself, and one more bearing that floats axially to deal with only the moment, then go for it.

Keith

[Marshall Grice]

a few thoughts.

I don't think Richard stated a max axial load, he was providing guidelines for proper sizing for a usable life span.

I personally don't agree with preloading the DG bearings to make them into angular contact bearings. I believe the preload is to just take up any slop in the bearing. I would imagine at that amount of preload the bearings would wear out very quickly. The physical distance between the bearings should be designed to properly react the moments. any change to the effective bearing center due to preload should be very small compared to this distance. I do however agree that if your inner spacer is larger then the outer race spacing with the outer races held by friction that there is a good possibility of the outer race slipping thereby removing your preload. I also agree that only one of the bearings is taking the trust loads. the direction of force and preload determining which bearing (for double deep groove bearing setup) is taking the load.

[Storbeck]

With deep groove ball bearings, spaced reasonably far apart, say two inches it seems to me like the couple to resist the moment load would come from equal and opposite radial forces on the two bearings. I took the moment and divided it by the distance between the bearings, and used that as a radial load on each bearing. This radial load is large enough to make the axial load insignificant. Say you have a 20 inch tire, with a 300 pound frictional force on the ground, so a 6000 inch pound moment. divide that by the spacing between th the bearings, say two inches, you have 3000 pounds of radial force on each bearing. Get a bearing big enough for that and it can easily handle the 300 pound axial load. Based on that logic I would say don't worry about spacers and just let one of the bearings float axially. Might as well let the inside bearing be the one that floats since it's load is added to the static weight load when cornering, and is therfore it is slightly more heavily loaded.

Am I mistaken?

However, I'm trying to figure out how to do this with a double row angular contact ball bearing, which is a little more complicated, because the two rows are so close together it is not an accurate approximation to say that the couple moment is just two opposite radial forces. The axial component is probably more significant since it has a larger radius.

Am I way off here?

[Richard Pare]

Max axial load capability of most manufacturers deep groove bearings is about 1/2 of the static load rating. I misspoke when stating the 10-12% figure - memory starts to go when you get grey hair!

One of the reasons for making the inner spacer longer than the distance between the outer shoulders and using the plates is to be sure that the thermal growth of the upright does not add preload.

While preloading the assembly will increase the installation stiffness, it will also decrease the available axial load capability, as that axial load induced by the preload gets subtracted from the max axial load capability, and what is left is what you have to work with. Since it is almost impossible to predict what the preload loading will actually be, the safe thing is to use no preload at all. I've seen a LOT of upright bearing failures by bearings that were preloaded, even by some supposedly knowledgeable people.

PS - Reynard used a rather small deep groove bearing to take the thrust loads on its CART car front uprights for many years.

You'd also be rather surprised at how good a finish quality you can get when turning hardened steel - most of the time it will be almost exactly the same as the original ground finish. Been doing this professionally for 30 years, and so far so good.

[Analogue]

Your calculations are correct, though here's some more things to think about.

You are assuming 2 inches between ball contact points, so the entire package would be closer to 2.75 long. That doesn't make for a small hub or upright.

Using a more realistic spacing will result in using a fairly large bearing for the forces involved.

Next issue is restraining bearings. You have to turn right and left, since this isn't NASCAR. That means that if one bearing handles all axial load, both inner and outer races need to be clamped.

For calculating things with angular contact bearings, take an instant center approach. Project the lines of action to the centerline of the shaft, and you get an effective bearing spacing wider than the set for a back to back setup. That's why properly matched angular contact bearings can have a very high moment stiffness, even in a narrow package.

By the way, we use the Rabbit bearings. They are already spaced, and have a split inner race. All they need is clamping force, and axial restraint for the outer race, and everything is set. They are also sealed. I would not get into dealing with angular contact individual pieces for an FSAE car.

In conclusion, don't screw with things that can't be machined to the tolerances necessary. Bearings are picky, FSAE cars are meant to be beat on and built by kids with bandsaws and hammers.

Keith