New type of bearing?

[Leffe]

Has anyone like me felt the need of a new type of ball/roller - bearing with an integrated sealing. Very often when designing some type of gearbox or other casing with a shaft coming out of it, one needs a sealing to keep the oil on the inside. To do this with a separate sealing makes the design bigger and more clumsy. It also makes it more expensive to manufacture. When it's time for repair it is easy to change the bearing but sometimes the sealing has wearn in to the shaft witch then needs to be exchanged or repaired. Wouldn't it be great with a ballbearing with an integrated sealing that seals between the inner and outer rings in the bearing? I understand that it needs to be fitted either over a o-ring or with some kind of glue or silicone to prevent leakage between the shaft and the inner ring as well as between the housing and the outer ring. It still would be a more effective design and it would be possible to use it in a lot of applications.
When I have asked people working for SKF, FAG or INA aboute this I have got what I think a very stupid answer: "We don't do it because no one asks for it." Ofcause no one asks for it since there isn't any such bearing.

WHAT DO YOU THINK?

Leffe

 

[EnglishMuffin]

As far as I can see - his design is (or could be) a standard seal incorporated in a bearing. There is no reason why you cannot replace the seal as he has drawn it without removing the bearing, other than the fact that he shows the location shoulder coming down past the seal. But there is no reason why this should be so. You can usually remove seals of this kind from the outside (at least the rubber encased ones). I have a number of damaged screwdrivers and mutilated seals to my credit to prove it!

 

[automatic2]

Yes, and another advantage would be a superior seat in both bores. Dual lip would help keep contaniments out. Tighten up the dimensions, and it will start to look very familiar.

 

[EnglishMuffin]

Whatever the merits are or are not, I don't think it matters because Leffe doesn't appear to be reading this any more and probably doesn't care what we think anyway !

 

[Leffe]

I do read it. As I have understood your point is wether the seal can be changed separately and how much a seal costs vs the cost of a ball bearing. I think it would be nice to hear the opinion of some more people too. I think that since the price of a ball bearing or a seal compared to one hours service time or one hours loss of production is so small, you are compleatly missing the issue. In massproduction I would expect the cost compared to a f.ex. 6004, to be something like 150% - 200%. I pay 1$ - 3$ for a 6004 today so the cost would not prevent me from using it until it passes maybe 50$. Please don't start a discussion aboute productioncosts of ballbearing industy now just because I mentioned $.
Leffe

 

[EnglishMuffin]

I thought that might goad you back into replying! Who is this "you" that is missing the issue? As far as I am concerned, I'm just throwing out as many thoughts pro and con as I can (that's what you need isn't it ?)- I, for one, don't think your idea is totally without merit.

 

[EnglishMuffin]

Automatic2:
Yes - it may look familiar, but it will not be identical !. For one thing, with Leffe's design there will be fewer precision diameters present (either one less or two less). And secondly, with Leffes design there will a seal running on through-hardened 62100 bearing steel - you can't do much better than that for seal reliability. From a designers point of view, it has merit. The big problem is getting initial acceptance and making it a de-facto standard. Until that happens, (if it ever could happen), there will a long period where such bearings are only available from one vendor, and nobody knows about them etc, and people can't get spares etc etc. But I have noticed a trend towards these combined components -especially in automotive. Take INA for instance - they seem to be making a lot of "combined" products. And I would never have believed that you would ever want to integrate ball bearings and front axle housings into one throw away part - but they do it now. Of course, I realize that automotive "consumers" are the same thing as industrial customers!

 

[EnglishMuffin]

Sorry - typo - I meant NOT the same thing as .... in that last sentence !

 

[automatic2]

And that does highlight one of the more important issues. If a consumer group identifies a need and contracts a supplier, they do so on a cost/profit bases. Without the identified need, you get the costs without the profits. "Build a better mouse trap and the world will beat a path to your door", is a phrase often used. That certainly doesn't mean that a unique idea can't be taken forward and applied in the field. It's just so much easier to have consumers pull products than for sales people to push products.

 

[EdDanzer]

The down side to having the seal in the bearing housing is one seal will not work in all applications. That is why there are so many different seal lip designs. If you have an application that a standard RS seal is not adequate, then case pressure, shaft speed, fluid type and external contamination become a factor. If volume it large you idea may save money. One way to end up with the same basic results is to make a seal ring and drop it in before the bearing, we have done this when the seal bore was damaged. We used a narrower seal in a stepped ring, bored the housing deeper and the cleaned out the old seal bore for the step to fit in.

 

[Thorn3]

Hello all,
I can easily see the potential use and practicality of such a bearing/seal combination. Not only does it allow for ease of installation, but cuts costs in many ways. No special materials or machining practices need be employed to utilize such bearings. Why not utilize the hard, ground surfaces of the bearing itself, as the seal surface? Isn't this cheaper than requiring the bearing seat material to be of such quality? With this in mind, yes, I can see the benefits of such a bearing.
When a typcial shaft seal is replaced, it is very common that not only is the seal bad, but also the metal frame that holds the seal. This is due to the forces and techniques of seal removal. So, in effect, two items are damaged, the seal material as well as the seal housing.
If the bearing itself is the seal housing, it is safe to assume that the simple removal of the bearing is all that is required to replace the seal material. Insert a new seal into the bearing housing, then simply reinstall the bearing. I am highly confident that the seal material itself, is less costly to replace, than the old method of changing the seal material along with the damaged seal housing.
I have seen a great deal of trauma to the gearbox, where the old seals are removed. The tools needed to remove such older seals, are indeed damaging to the gearbox itself. With Leffe's idea, there would be no damage to the gearbox or shaft, as well as the potential to keep the original bearing. Simply replace the seal in the bearing.
Let's face it, utilizing the exotic materials of the bearing itself, lessens costs of specialized materials and machining of the shaft and the gearbox material. Don't these savings in themselves, warrant further investigation into his bearing idea? Honestly, one cannot beat the hardness and sealing capacity of the bearing material itself.
As for getting people to accept the idea: When the telephone was invented, people thought it was a wondeful device, but nobody believed it would ever catch on, because they didn't believe that anyone would have so much to say to each other to warrant the purchase of a phone. Is this the initial stupidity of man when faced with something new?
I see two products here. One is a resealable bearing and the other is the seal the bearing uses. As it is now, if I use a sealed bearing, and the seal fails, I have to purchase a whole new bearing. I personaly would rather keep my good bearing, and just replace its seal for a fraction of the cost. On top of that, I would praise the ability to save tremendous costs in machining and materials of the machine itself that the bearings go into. Wouldn't any of you?
Good job Leffe, I am curious to see where this goes.