cages in slewing ring bearings

[Gerry45]

A supplier has recommended that we change from plastic spacers to steel band type cages on the large pitch control bearings of wind turbines. He argues longevity as the reason but there has been no evidence of deterioration of the current plastic parts. The bearings run cold and the greases used are conventional moly type with no strong EP additives.

Most of the rest of the bearing world is moving towards polymer cages because of their numerous advantages. I cant think of any good reasons why our supplier wants to go against the flow....other than perhaps it may simplify his assembly procedure and perhaps save him some money ?

Whats more, the cages are laser cut in the ball pockets and are dog rough. A significant amount of material has to wear from the pockets before the ball makes a sufficiently conforming surface and the 'run-in' process settles down. We then have to remove all this extra debris by increasing the grease flow or suffering greater debris damage if we dont.

Any thoughts anyone as to why steel would have been proposed as an upgrade ?!

 

[plasgears]

The world is converting from metal to plastics, and this is another example of the trend. In order to help protect this application, the spacer should be sturdy and self lubed.

 

[MASSEY]

Hold on there a minute. Not everyone is sold on the idea of plastic bearings.

For our applications it is ridiculous.

If you have a poor quality bearing - and there are some - then buy a good one from a reputable manufacturer.

Or use plastic if it works for you and you are happy with it. You are the customer.

But please don't think all steel bearings are bad, they are not. On the contrary, I see melted, mangled nylon all the time. We fix the stuff with REAL bearings and the customer is happy.