Oscillating Bronze Bearing Life Test

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- Mark Stewart
  
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posted
19 years ago

Thu, May 20, 2004 8:19 PM

We have collected pressure-velocity at time PVt data for a bronze sleeve bearing running (small oscillations +-3 deg) on a stainless steel shaft and would like to conduct an accelerated test to determine the wear characteristics. If wear is a function of PVt how do we balance the effect of pressure P, sliding velocity V and sliding time and sliding distance without putting to much heat into the bearing. Are there general rules regarding how much we can increase P or V in order to shorten time?

Mark

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- Brian Whatcott
  
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posted
19 years ago

Fri, May 21, 2004 12:12 PM

Unless there are aggravating factors you have not mentioned, you should not be conducting this test, at least not on this geometty.

1) The wear characteristics of such sleeves are well known.

2) Conduct a life test on a test article that can be continuously loaded, say at +20% load and velocity for continuous time, e.g. press a button of the sleeve material on a rotating shaft turning contimuously. Make the obvious adjustments (re temperature rise etc.)

Brian W

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- Mike Halloran
  
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posted
19 years ago

Sat, May 22, 2004 5:58 AM

I'm not sure that a continuous rotation test would correlate to the application.

Bronze bearings, porous or not, exhibit good life when they are allowed to develop a hydrodynamic bearing film, however thin. Bronze's big advantage is that it doesn't mar a mating steel surface during startup, before the film has developed. Small oscillations effectively put the bearing system through a startup twice per cycle, so I'd expect a life much shorter than the usual calculations would predict. I assume that's the reason for proposing the test in the first place; they're already experiencing anomalously limited life.

For a rotation of only 6 degrees total, they probably should be looking at flexures.

-Mike-