NEED BUSHING WITH HIGH PV VALUE

[Schroyer]

We are trying to come up with a solution to a bushing problem. We have a bushing in an reversing application where a sleeve rotates +/- 15° within a bushing continuously. The sleeve has a 2-3/4" OD for reference.

I need something that will withstand a Velocity of V=210 fpm, P= 2000 psi (force that pin puts on projected area of bushing), and a pv value around 450,000.

An initial attempt was Mag-bronze with grease. After running through these numbers I can see why it didn't work.
Mag Bronze Max P=8,000 , Max V = 100, max PV=150,000
Any ideas?

Thanks,
Schroyer

 

[diamondjim]

Is there a better grease that
has additional additives to
allow the greater pv value?
Is it getting too hot at those
fpm speeds.

 

[Schroyer]

I'm not sure if there is a better grease for this or not. I put a question in the "Tribology" forum also. Maybe they have a suggestion.

The bushing lasts approximately 3 months before failure.
Heating up has not been an issue.

 

[Tmoose]

Is failure smooth wear of shaft and/or bushing? Uniform across width, or showing edge loading due to machined-in alignment or distortion? How many oscillations happen in 3 months?

Seems like bronzes need a heap of lead in the recipe to survive marginal lube situations.
I seem to recall the shaft finish and hardness can help some, but establishing REAL lubrication is at least 10 X more effective than going to Rc 60 parts.

 

[unclesyd]

Here is website for Bearium metal.
We used this alloy in some very highly loaded applications.
This is highest lead content bronze around as recommended by Tmoose. Don't use the lack of lubrication properties, use a good lubrication system.

You will probably have to call them as their website isn't very informative. I did have some literature but it got lost.

http://www.metaltekint.com/Bearium/

 

[Schroyer]

Thank you everyone, I will call Bearium metal and see what I can find out. I appreciate the help on this.

 

[wmv]

You should consider a polymer bushing Fluorolon 4000 (PPS)
bearing or Fluorolon 3000 (PEEK). You can acheive PV over 400,000 in both lubricated. <

http://www.aptechno.com>

Good Luck.

 

[abeschneider]

Did you come up with a solution? I also have an application needing high PV bushing material; I have a 100mm shaft, running at 225 rpm, with a 55kN load. So I need a PV of at least 6.5 MPa-m/sec. Note also, my bushing must be able to handle surface speeds of 1.2 m/sec. The bushing and shaft will be underwater at all times, so I think I can benefit from cooling and lubrication of water. I'd be curious to learn what you've learned. My top choices so far are PEEK, and ToughMet from Brush-Wellman (

http://www.brushwellman.com/alloy/products/copper_nickel_tin/adg6120.asp)

 

[unclesyd]

abeschneider,
You should always start a new thread with a new question.

You should take a look at following and give them a call.

http://www.duramax-marine.com/bearings.htm

 

[unclesyd]

abeschneider

Here is another source of Hydro bearings. The site is a little tricky to navigate.

http://www.tenmat.com/bearings/index.html