Abstract: 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 ? position and one or more kinds of saturated monovalent fatty acids having 9 to 13 carbon atoms.

Abstract: 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.

Abstract: A lubricant, comprising: a base oil as primary lubricant component, and a naphthenate salt as additive (A), and an alkylimidazole compound as additive (B), added to the base oil, preferably further comprising an aliphatic amine compound as additive (C), a fluid dynamic bearing with the lubricant filled therein, a spindle motor with the fluid dynamic bearing installed therein, and a magnetic disk device with the spindle motor installed therein.

Abstract: 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.

Abstract: 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.

Abstract: The problem to be solved by the present invention is to provide an ionic liquid-containing lubricating oil composition that has extremely low viscosity and does not evaporate during use. This problem is solved through the use of a lubricating oil composition that contains as a base oil an ionic liquid with a kinematic viscosity of 5-20 mm2/s at 40° C., and a polymerization inhibitor with a molecular weight of 200-600.

Abstract: The aim of the present invention is to provide a lubricating oil composition for a hydrodynamic bearing device wherein oil film disruption is suppressed. It is solved by a lubricating oil composition for a hydrodynamic bearing device which comprises a base oil and an oil film disruption inhibitor such as metal sulfonate.

Abstract: 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 ? position and one or more kinds of saturated monovalent fatty acids having 9 to 13 carbon atoms.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A lubricant, comprising: a base oil as primary lubricant component, and a naphthenate salt as additive (A), and an alkylimidazole compound as additive (B), added to the base oil, preferably further comprising an aliphatic amine compound as additive (C), a fluid dynamic bearing with the lubricant filled therein, a spindle motor with the fluid dynamic bearing installed therein, and a magnetic disk device with the spindle motor installed therein.

Abstract: 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.

Abstract: The invention provides a hydrodynamic bearing device, comprising 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; wherein 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.

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

Abstract: The invention provides a hydrodynamic bearing device, comprising at least one of a shaft and a sleeve having a dynamic pressure-generating mechanism, and a lubricant present in a gap between the shaft and the sleeve; wherein the lubricant contains at least one compound selected from the group consisting of aliphatic ethers having a total carbon number of 24 to 32 as represented in Formula (1) or Formula (2) R1—O—R2??(1) R3—O-A-O—R4??(2) and wherein R1 represents a C16 or higher alkyl group having at least one side-chain, R2 represents a C4 or higher alkyl group, the carbon number of R1 is greater than the carbon number of R2, R3 and R4 represent C8 or higher alkyl groups, A represents a C5 or higher CnH2n group, and at least one of R3, R4, and A have a branched structure.

Abstract: 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.

Abstract: 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 ? position and one or more kinds of saturated monovalent fatty acids having 9 to 13 carbon atoms.

Abstract: The semiconductor substrate comprises a silicon substrate 10, a silicon germanium layer 12 formed on the silicon substrate; and a silicon layer 14 formed on the silicon germanium layer. At least one of an isotope composition ratio of one Si isotope and an isotope composition ratio of a Ge isotope of at least one of the silicon substrate, the silicon germanium layer and the silicon layer is above 95%. In at least one of the silicon substrate, the silicon germanium layer and the silicon layer, at lest one of an isotope composition ratio of one Si isotope and an isotope composition ratio of one Ge isotope is set higher, whereby the heat can be scattered in the direction horizontal to the substrate plane. Thus, the semiconductor substrate can have higher heat radiation.

Abstract: A highly reliable liquid bearing unit is provided, which can, by securely repelling a lubricant by an oil repelling film, prevent the lubricant from leaking and a magnetic disk device mounted therewith. In a case where the lubricant contains a constituent of at least one of a hydrocarbon-based oil and an ester-based oil and the oil repellent film is a film of at least one of a fluorine base and a silicone base, surface tension of the lubricant is made greater than the critical surface tension of the oil repellent film by 5 mN/m or more. Moreover, when the lubricant is a fluorine-based lubricant, surface tension of the lubricant is made greater than the critical surface tension of the oil repellent film by 8 mN/m or more.