Panasonic Corporation

Katsushi Hirata

Takanori Shiraishi

Hideaki Ohno

A hydrodynamic bearing device being low in torque, low in power consumption, high in reliability and best suited for miniaturization and a spindle motor using the same. The hydrodynamic bearing device in accordance with the present invention, dynamic pressure generation grooves being provided on at least one of a shaft or a sleeve, and a lubricant being present in a clearance where the above-mentioned shaft and the above-mentioned sleeve are opposed to each other, is characterized in that the above-mentioned lubricant contains diesters obtained from a divalent alcohol having 4 to 8 carbon atoms and having no alkyl side chain at the &#x3b2; position and one or more kinds of saturated monovalent fatty acids having 9 to 13 carbon atoms.

Hydrodynamic bearing device and spindle motor using the same

A hydrodynamic bearing device, comprising a shaft structure, a sleeve, a dynamic pressure-generating groove which is formed on surface of at least one of a shaft structure and a sleeve, and a lubricant present in a gap between the shaft structure and the sleeve; wherein the lubricant contains a diester with a total carbon number of 20 to 28 obtainable by a divalent alcohol that has three ether bond, and one or more types of a saturated monovalent fatty acid with carbon number of 6 to 10.

Hydrodynamic bearing device, and spindle motor and information device using the same

Lubricant for fluid dynamic bearing, spindle motor equipped therewith and magnetic disk unit

The invention provides a hydrodynamic bearing device including at least one of a shaft structure and a sleeve having a dynamic pressure-generating mechanism, and a lubricant present in a gap between the shaft structure and the sleeve. The lubricant contains a diester with a total carbon number of 20-28 obtainable by a divalent alcohol that has at least one ether bond, and one or more types of C6 to C10 saturated monovalent fatty acid.

A hydrodynamic bearing device comprises at least one of a rotating component and a fixed component having a dynamic pressure-generating mechanism, and a lubricant present in a gap between the rotating component and the fixed component; wherein the lubricant contains at least one compound selected from the group consisting of aliphatic ethers having one or more ether bonds and a total carbon number of 24 to 39.

A hydrodynamic bearing device has high reliability and is suitable for miniaturization through superior heat resistance and by utilizing a dynamic pressure-generating liquid with little loss due to evaporation. The hydrodynamic bearing device has at least one of a shaft structure and a sleeve having a dynamic pressure-generating mechanism. The dynamic pressure-generating liquid present in a gap between the shaft structure and the sleeve has a main component that is ionic liquid.

The present invention provides a fluid bearing unit capable of achieving lower torque and lower current consumption in comparison with a conventional bearing unit, and a spindle motor using the same. The present invention employs an ester derived from 1,5-pentanediol having one alkyl side chain and saturated monovalent fatty acid having 5 to 8 carbon atoms as a base oil of a lubricant with which a gap between a shaft and a sleeve is filled.

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Ozu, Japan

Katsushi Hirata