Positive locking for sphericals

[jd74914]

This is not a solution to your problem, but for all the teams that use snap rings: how do you avoid slop in these joints? Do you shim each and every one of the bearings against the snap rings into the housings? I guess slop here may not be the worst thing (doesn't affect control arm length that much really) but just seems very sketchy.

Grinding away that part of the snap ring very likely makes it difficult to remove the snap ring right? Is the snap ring method easier for you to manufacture? Or do you do it so you can remove the bearings and re-use?

I would hope everyone is machining the bore to specified press fit. The stakes or snaps really are only to prevent the bearing from coming out in event of press failure.

[harshitr2]

Grinding away that part of the snap ring very likely makes it difficult to remove the snap ring right? Is the snap ring method easier for you to manufacture? Or do you do it so you can remove the bearings and re-use?

Yes, it makes installation and removal of the bearing a little messy, because the snap ring interferes with the ball on removal and installation. And yes, snap ring method seems easier for us. There are a few members in our team who have become very proficient in machining snap ring grooves! Also, as others have said, the control arm becomes a replacement part once bearings are staked. Non availability and non familiarity with staking tools is also a reason.

[J-rob68]

You can always use spirolox retaining rings as an alternative to snap rings if you are having clearance issues. Check the link below for more info. We use these in our production control arms and camber plates.

http://www.smalley.com/retaining-rings/spirolox

[harshitr2]

Those might be the way to go, Jason, spiral retaining rings. Thanks for your inputs!

[darges]

I'll just add that we have used those spiral retaining rings for years on our chassis side bearings. They're a little difficult to get in, but using a thin razor blade usually makes the affair simple. They can be found pretty easily from suppliers like Grainger too.

[Z]

Why you students always over-complicate things?


(Obviously, they also work in internal grooves.)

"Round-wire circlips (or snap-rings)" are so simple you can make them yourself. Just some stiff (= high-ish tensile) wire wrapped around a round bar of appropriate diameter.

Or you can use softer wire (eg. galv. med-tensile fencing wire) and press it into the groove in such a way that it gets riveted in there for a semi-permanent fit (use small drill and "pick" to undo). This also removes any play of the spherical in the housing. A drop of Loctite also helps.

Z

[J-rob68]

Yes lets manufacture parts for simplicity rather than purchasing readily available, engineered and tested parts with shear data already provided . All good infor here though and certainly could be an interesting piece to work with for some of the freshmen engineering students to apply some basic hand calcs and make parts for the car. But when time and rescources are extremely scarce in the fsae world I think its a bit silly to waste time on those sorts of things.

I think its great so many different options have been shown here, I always made a huge point to take as many pictures of different applications at competition so that I could brainstorm and utilize the best of each design as I saw fit. Personally Im a fan of staked bearings if you have the machining capability to knock those out quick enough and with the proper tolerances. This saves you quite a bit in overall part count and surprisingly a chunk of weight too. cool ideas guys.

[Swiftus]

...staked bearings if you have the machining capability to knock those out quick enough and with the proper tolerances...

If the car needs to get back out on track ASAP, a screwdriver and a hammer do a mighty fine job of staking a bearing for a day.

[MCoach]

...staked bearings if you have the machining capability to knock those out quick enough and with the proper tolerances...

You mean this isn't a freshman project at other schools? This is usually one of the first things that team members were introduced to. We never have had a staked bearing assembly fail. However, from several cars that were around from before my time, I have had sphericals fall out of the buckets into my hand while working on them due to improperly machined or worn out circlips, grooves, and/or buckets. As JD pointed out, they're supposed to be press fit in the first place. What are you trying to save my recycling sphericals or control arms?

[acedeuce802]

You mean this isn't a freshman project at other schools? This is usually one of the first things that team members were introduced to. We never have had a staked bearing assembly fail. However, from several cars that were around from before my time, I have had sphericals fall out of the buckets into my hand while working on them due to improperly machined or worn out circlips, grooves, and/or buckets. As JD pointed out, they're supposed to be press fit in the first place. What are you trying to save my recycling sphericals or control arms?

This. Buy stock at the proper OD, get a good carbide drill that's slightly undersized, and a good reamer to make a 0.000" press, but ream after welding. Then a countersink bit and some kind of depth gauge to double check. Be conscious that reaming will make the countersink smaller. Once we got the proper tooling, the operation took 5 minutes per part. The only axial spherical failures I've seen were the ball popping out of the race before the stake let go.