DISC DRIVE SPINDLE MOTOR HAVING HYDRO BEARING WITH OPTIMIZED LUBRICANT VISCOSITY

摘要

A disc drive (10) includes a housing (12), a central axis (80), a stationary member (34) which is fixed with respect to the housing and coaxial with the central axis, and a rotatable member (36) rotatable about the central axis with respect to the stationary member. A stator (38) is fixed with respect to the housing. A rotor (70) is supported by the rotatable member and is magnetically coupled to the stator. At least one data storage disc (16) is attached to and is coaxial with the rotatable member. A hydro bearing (37) interconnects the stationary member and the rotatable member and includes a blend of a base fluid (84) having a viscosity index of at least (110), an anti-oxidant additive, an anti-corrosive additive and an anti-wear additive, which are effective for resisting catalytic degradation in the hydro bearing.