Planetary Gear Lubrication

[fti]

I am currently prototype testing a single stage planetary gear that is a 5:1 reduction with an input speed/hp of 3500 rpm/1-1/2 hp. It is all steel in construction and is contained in an aluminum housing. This gear was chosen for its small size, low mass and high efficiency. It is being used as a speed reducer between and induction or air motor and a progressing cavity pump. The gear temperature with a continuous duty cycle is higher than I expected however - around 230 F which is 140 F above ambient and 90 F above pumpage temperature. The gear manufacturer (actually distributor) simply recommended "any lithium based grease" with no guidelines on amount etc. The "any lithium based grease" I used seems to oxidize rather quickly at 230 F.
Any specific recommendations regarding lubricant type, quantity, aditives etc. for this gear and application would be very much appreciated. Thank you,
fti

 

[plasgears]

We moved from petroleum greases to poly-alpha-olefin greases, and we have never regretted it. The VI is quite acceptable, and the temp range is very high. We got the first recommendation from a customer, and we later standardized on it. Try Aerospace Lubes in Columbus, OH. Don't let the name fool you; the company serves a diverse customer base.

 

[Metalguy]

Dow-Corning has/had? a fluorosilicone grease (FS 3451) that may work well for you. It is OK at very high temps., but incredibly expensive.

 

[SERVOCAM]

Try this:

http://www.nyelubricants.com

Nye, Nyogel 792D, a synthetic grease suitable for a wide temperature range from -40oF to 257oF ( -40oC to 125oC ). Nyogel is a thixotropic grease which under dynamic (working) conditions will flow and then return to a gel consistency under static (rest) conditions

Used by servo grade planetary gear boxes.

Cameron Anderson - Sales & Applications Engineer
Aerotech, Inc. -

http://www.aerotech.com

"Dedicated to the Science of Motion"

 

[RHD]

I use Diester based greases in our gearboxs such as Aeroshell 12. It has a good temp range. The obvious question is, can you use an oil? This would give the best cooling for the gear teeth. If you can't seal the oil in, then a grease is required.