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Fluid Bearing Spindle Motor with Special Lubricant Disclosure Number: IPCOM000013718D
Original Publication Date: 2002-May-02
Included in the Prior Art Database: 2003-Jun-18

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Disclosed is a system of additives comprising oligomers of dioctyldiphenylamine and phenylnaphthylamine (Vanlube 9317), tricresyl phosphate, and optionally, a conductivity additive DuPont STADIS 450 formulated into synthetic oil, which then has superior thermal oxidative stability. The formulated oil will provide a longer lifetime than base oil without these additives when used in a fluid dynamic bearing (FDB) motor. The FDB oil must be electrically conductive and stable with respect to oxidation. Presently available FDB oils contain antistatic additives but are not formulated with antioxidant or metal passivator additives. The available FDB oils are adequate for light-duty applications such as VCR recorders. When the available FDB oils are employed in disk drive motors, and subjected to multiple start/stop operations, the bearing fails due to oil degradation. Additives were evaluated by formulating them into the base oils listed in Table 1. Table 1. The base oils used to evaluate the fluid dynamic bearing oil formulations. DOS di(2-ethyl hexyl) sebacate DOA di(2-ethyl hexyl) adipate TMP trimethylol propane ester of C7 acid, ICI Chemicals EMKARATE 1510 TRIH tricaproin, ethylene glycol trihexanoate