On Fri, 9 Dec 2016 14:41:12 -0800 (PST), wrote:

On Friday, December 9, 2016 at 5:22:36 PM UTC-5, Christopher Tidy wrote:
Thanks for all the useful answers. I'm looking for examples of common products which are currently in production, and where a risk of sudden failure exists if the bearing fails to behave properly. Slow and lightly loaded applications aren't so interesting, as the design isn't critical and the price is going to be the main factor.

Car engines and jet engines are interesting. The last small engine I took apart (400 cc) had rolling element main bearings, whereas a similar older engine (600 cc) had huge plain bearings and hardly any signs of wear. I also saw a compressor with a ball bearing in the big end of the connecting rod recently. This got me thinking. I don't see so many plain bearings in modern products, or at least nothing so visible as the bronze sleeves in my 1960s power hacksaw and 1940s sewing machine. But maybe "see" is the important word.

Can anyone tell me what kinds of bearings are used in specific car engines from well-known manufacturers today? Volkswagen, Ford, Mercedes, etc.? An example or two would be useful

Thanks for the information.

Best wishes,

Chris

Every make you mentioned uses plain shell bearings. Very few engines are built with roller crankshaft bearings today, and those are, as far as I know, all small, high-performance 2-strokes. Even they may have switched; I haven't kept up.

The advantages of roller bearings in an engine apply where there is little lubrication and high loads -- thus, the two-strokes. There were some roller-bearing F1 4-strokes among the V10s (they were ceramic) but no longer.

The friction issue is about a wash overall in IC engines. One additional issue with roller bearings is that they take up too much space in a compact engine crankcase.
Two strokes use rolling element bearings because at the speeds they
operate at only a very small amount of lube is required. In fact, too
much oil or oil pressure will cause the rolling elements to skid which
leads to failure. As Ed says all major engine makers use plain
bearings. Plain bearings can also be an advantage when the oil may be
dirty. This is because, in part, the dirt particles either embed into
the bearing material or are pushed out of the way. Rolling element
bearings can be caused to skid on fine dirt particles. This of course
leads to rapid bearing failure. Sometimes the dirt particles will get
rolled over by the rolling elements and this distorts the bearing
parts. This distortion can be elastic or plastic. Constant elastic
distortion leads to premature failure from fatigue. Plastic distortion
means that the bearing part is permanently distorted which also leads
to rapid failure. Plain bearings can be made so that they will
tolerate quite a bit of fine particle embedment without the particles
acting as an abrasive. This is because the particles actually end up
just beneath the bearing surface. Certain bearing materials, such as
silver, have remarkable fatigue lives so they last a very long time.
The above are just some of the reasons that plain bearings continue to
be used in car engines, electric motors of all types, and even very
heavy loaded shafting in hostile environments. With the materials used
today plain bearings show exemplary lifetimes in demanding
applications. A car engine today from any decent maker is expected to
last at least 150,000 miles. At least. And this is in a situation
where the user doesn't always change the oil as often as they should.
And even though we tend to think of a bearing as something that rolls
plain bearings can also be sliding. A great common example is a piston
sliding up and down in a car engine. Failure of the bearing surface(s)
in a cylinder will definitely lead to catastrophic failure. And it's
not just the piston to cylinder bearing surfaces but also the piston
ring to cylinder surfaces that need to work for a long time. I think
you now have plenty of examples of common uses of plain bearings
Chris,
Eric