Bearing lubrication 1

[Xela77]

I am trying to lubricate bearings of a power train, introducing the oil from the shaft to the bearing, this way, when the shaft spins, all the oil will flow from inside to outside thanks to the centrifugal force, and also thanks to the small pressure I have in the shaft, almost 7 psi. My questions are the followings:
- Do we need to have the bearing continuosly lubricated through a constant flow? (In my case I am doing this way) Or is is enough, just with some oil drops (instead of the continuos small oil flow)?
- In case we need a continuos flow, how much flow do we need (I guess it has to be really small)? Which is the relatioship between the flow, and load, speed, size, ...
Thanks a lot to every one who reads my problems!

 

[ccw]

Hi Xela77,

You have not provided enough information to make the decisions: drip vs. continuous, and the flow rate if continuous.

Are the bearings of the power train journal bearings or antifriction ball bearings, roller bearings, needle bearings, etc.? How much thermal power is developed by each of the bearings, peak and continous?

If you are pumping 7 psi into internal ports in the shaft, where is the oil coming from? Is it recirculating? Is there a oil/air, oil/water heat exchanger planned? Are there other friction/heat power generating elements in the power train that are exposed to the same oil?

What are the risks if the oil supply is interrupted?

 

[ccw]

Hi again Xela77,

For information on grease vs. drip. vs spray lubrication quantities required on high speed spindle bearings (angular contact ball, or roller, or ball and roller combination) see pages 62-68 of FAG/Barden Superprecision Bearing Catalog. I think the catalog is online or can be obtained on CD from the FAG company.