Ntn Corporation

Shinji Komatsubara

Tetsuya Kurimura

Yasuhiro Yamamoto

Fuyuki Ito

Kazuyoshi Harada

Tadahiro Uchiyama

Yoshinori Ito

Jun Hirade

Katsuo Shibahara

Takao Arai

Toshiaki Niwa

Shouhei Oka

An internal pore of a sintered metal bearingis impregnated with a lubricating fluid, and a radial dynamic pressure generation portionis formed on an inner peripheral surface. An axial dimension L is 4.8 nm or less, a thickness dimension t is 0.5 mm or more and 1.5 nm or less, and a ratio L/Dof the axial dimension L to an outer diameter dimension Dis 0.24 or more and 0.6 or less.

Oil-impregnated sintered bearing and fluid dynamic bearing device provided with the bearing

A fluid dynamic bearing deviceincludes: a shaft member; a bearing sleevethat has the shaft memberinserted into the inner periphery thereof; a housingthat holds the bearing sleeveon the inner periphery thereof and has a bottomed cylindrical shape having an opening at an end portion on one axial side; and a seal memberprovided at the opening of the housing. The seal memberhas a disk portiondisposed on one axial side of the bearing sleeve, and a protrusion (cylindrical portion) protruding to the other axial side from an outer diameter end of the disk portion. An outer peripheral surfaceof the seal memberis fixed to an inner peripheral surfaceof the housing

Fluid dynamic bearing device

Provided is a slide bearing (bearing sleeve ()), comprising an oxidized green compact in which particles () of metal powder are bonded to each other by an oxide film () formed on surfaces of the particles (). The oxidized green compact has a bearing surface (A, B) configured to slide, through intermediation of a lubricating film, relative to a mating member (shaft member ()) to be supported. The bearing surface (A, B) has a large number of opening portions (), and the large number of opening portions () and inner pores () are interrupted in communication therebetween by the oxide film ().

Slide bearing

A charging amount of lubricating oil () into an internal space of a housing () is adjusted so that, within a range of a use temperature, an oil level of the lubricating oil () is positioned on a lower side with respect to an upper end portion of a chamfered portion () formed in an upper-end inner peripheral edge portion of a bearing member (). The bearing member () integrally includes: a small-diameter cylindrical portion (); and a large-diameter cylindrical portion (). Under a state in which an upper end surface () of the small-diameter cylindrical portion () is exposed to an atmosphere, the large-diameter cylindrical portion () is sandwiched from both sides in the axial direction with an annular member () and a bottom portion () of the housing () so that the bearing member () is fixed along an inner periphery of the housing ().

Fluid dynamic bearing device and motor with same

An oil-impregnated sintered bearing () includes a copper-iron-based sintered compact containing 40 mass % or more of copper, and has inner pores impregnated with an oil. The sintered compact has: a copper structure derived from copper powder () of partially diffusion-alloyed powder () in which copper powder () having a particle diameter of 20 &#x3bc;m or less is diffused on and joined to a surface of iron powder () in advance; and a copper structure derived from elemental copper powder ().

Oil-impregnated sintered bearing and method for manufacturing same

A sintered metal bearing is formed of a porous body formed through sintering of a compact obtained through compression molding of raw-material power. The sintered metal bearing includes a dynamic pressure generating portion formed on an inner peripheral surface, the dynamic pressure generating portion including dynamic pressure generating groove array regions formed continuously to each other in an axial direction of the sintered metal bearing. The dynamic pressure generating groove array regions each include a plurality of dynamic pressure generating grooves arrayed so as to be inclined with respect to a circumferential direction of the sintered metal bearing. An axial dimension of the sintered metal bearing is set to 6 mm or less, and a density ratio of the sintered metal bearing is set to 80% or more and 95% or less.

Fluid-dynamic bearing device provided with a sintered metal bearing and a fan motor provided with the fluid-dynamic bearing device

A ratio W/Wof a circumferential width Wof each of inclined hill portions Gof a radial dynamic pressure generating portion G and a circumferential width Wof each of inclined groove portions Gis 1.2 or larger. And when an inner diameter of a bearing member is D, the circumferential width Wof each of the inclined groove portions satisfies 0.2D&#x2264;W&#x2264;0.4D.

Fluid dynamic bearing device, and bearing member and shaft member for use in same

Provided is a fluid dynamic bearing device () including a rotary body (A), a bearing member () (sleeve portion) made of a sintered metal arranged on the rotary body (A), having end surfaces (), a thrust bearing gap formed by a lower end surface () of the bearing member (), filled with lubricating oil (), and a thrust dynamic pressure generating portion (B). A dynamic pressure generating action is caused in the lubricating oil in the thrust bearing gap along with rotation of the rotary body (A) to support the rotary body (A) in one thrust direction in a non-contact manner. The bearing member () has an oil permeability of 4% or more with respect to a mass flow rate of the lubricating oil () flowing along the thrust dynamic pressure generating portion (B) during the rotation of the rotary body (A).

Fluid dynamic bearing device and motor provided with same

A sintered bearing includes a sintered metal formed by using a metal powder mixture containing copper powder and iron powder. The metal powder mixture contains 80 wt % or more of particles having an average particle diameter of less than 45 &#x3bc;m. The copper powder contains electrolytic copper powder. The electrolytic copper powder contains 40 number % or more of particles having a circularity of 0.64 or more.

Sintered bearing and method of manufacturing same

A fluid dynamic bearing device including: a bearing sleeve fixed to an inner periphery of a housing; a shaft member removably inserted along an inner periphery of the bearing sleeve; an annular member having an inner peripheral surface for defining a radial gap together with an outer peripheral surface of the shaft member; and radial bearing portions and a thrust bearing portion for supporting the shaft member. At least the radial bearing gap at each of the radial bearing portions, and a bottom gap having the thrust bearing portion received therein are filled with lubricating oil. A void section is formed in an interior space of the housing. Assuming that drepresents a gap width of the radial bearing gap and drepresents a gap width of the radial gap, a relationship of 30d&#x2266;d&#x2266;250dis satisfied.

A fluid dynamic bearing device (), including: a bearing member () on a rotary side; a housing () on a stationary side; a sealing member (); a radial bearing gap to be formed between an outer peripheral surface () of the bearing member () and an inner peripheral surface () of the housing (); and a thrust bearing gap to be formed between a lower end surface () of the bearing member () and an inner bottom surface () of the housing (). The radial bearing gap and the thrust bearing gap are filled with lubricating oil (). An axial gap () containing air is formed between an upper end surface () of the bearing member () and a lower end surface () of the sealing member (), which faces the upper end surface () of the bearing member ().

Growing community of inventors

Mie, Japan

Shinji Komatsubara