Lubricant composition, useful in fluid dynamic bearing systems, which are useful for the rotational mounting of a spindle motor, comprises base fluid and an additive comprising polyethylene oxide-sorbitol ester

摘要

Lubricant composition comprises at least one base fluid and at least one additive comprising polyethylene oxide-sorbitol ester. Independent claims are included for: (1) dynamic fluid bearing system for the rotational mounting of a spindle motor, comprising a first bearing component having a first bearing member (12, 16, 18) and a second bearing component having a second bearing member (20, 24), where the second bearing component is separated from the first bearing component by a bearing gap filled with a lubricant (22, 26) and rotatably mounted relative to this, and the lubricant is the lubricant composition; (2) spindle motor with fluid dynamic bearing system for the drive of storage disks of hard disk drives, comprising a base plate (10), in which the first and second bearing components are held, and a hub (14), where the second bearing component is separated from the first bearing component by the bearing gap filled with the lubricant and together with the hub is operated by an electromagnetic drive system (36, 38, 40) rotationally driven about a common rotation axis (30); and (3) the hard disk drive having a spindle motor comprising at least one rotatably drive storage disk, and a read-write means for writing and reading data to and from the storage disk.