A NEW APPROACH TO LUBRICATING BALL BEARINGS.
NAVAL RESEARCH LAB WASHINGTON D C
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A study was undertaken of the causes of unsatisfactory service and storage life of Navy synchros and servo motors. Silicone oils have been in wide use as the lubricant for the ball bearings of these devices because of the good low-temperature characteristics of these materials. Examination of bearings from synchros which failed qualification tests gave evidence of fretting corrosion, broken bearing retainers, dry residues, and loss of lubricant. A white flocculent substance was found in new silicone-lubricated bearings. This substance could be reproduced in the laboratory at room temperature when rubbing ferrous metals were lubricated with silicones. The principal cause of early synchro and servo motor bearing failure is believed to be the creeping away of the small supply of silicone lubricant from the load-carrying area of the bearings under service and storage conditions. Studies proved that a lubricant based on bis2-ethylhexylazelate satisfactorily lubricated synchro bearings at temperatures as low as -55C. Creeping of lubricants composed either of the azelate ester or of silicones from ball bearings was prevented by the use of lowenergy fluorochemical barrier films. The life of synchros containing bearings treated with the barrier film and lubricated with a bis2-ethylhexyazelate composition has increased from 300 hours to nearly 4000 hours on standard qualification tests.
- Lubricants and Hydraulic Fluids
- Machinery and Tools