Ntn Corporation

Other

Nidec Corporation

J. Morita Manufacturing Corporation

Masaharu Hori

Masaaki Toda

Isao Komori

Natsuhiko Mori

Tetsuya Yamamoto

Yoshiharu Inazuka

Tetsuya Kurimura

Kenji Ito

Fuminori Satoji

Kenji Hibi

Toshiyuki Mizutani

Kimihiko Bito

Wei Shin Sim

Yasuhiro Yamamoto

Nobuyoshi Yamashita

Akira Matsui

Shigeharu Sumi

Masahiro Kurita

Yoshinori Morita

Hiroyuki Noda

Naoki Nakagawa

Mitsuo Sasabe

Seiji Shimizu

Kazuto Shimizu

Kimihiko Bitou

Jun Hirade

Tatsuya Hayashi

Takeshi Maeda

Nobuyuki Mori

Toshiaki Niwa

Masahiro Kato

Itsuo Murata

Masaya Soeda

Souichi Yagi

Providing a fluid dynamic bearing device, wherein the outer member comprises a member formed by a pressing process on a plate member, the radial bearing surface and at least the one of the thrust bearing surfaces of the outer member being formed by the pressing process, and wherein at least a part of the inner member, which forms the radial bearing surface and the thrust bearing surfaces of the inner member, is made of a sintered metal.

Fluid dynamic bearing device and assembly method for same

A bearing capable of satisfying demands for cost reduction and further quietness, and stably maintaining high support accuracy. A sliding bearing () includes an inner member () having a mounting surface () with respect to a rotary shaft (), and an outer member () being arranged on a radially outer side of the inner member (). A radial bearing gap is formed between an outer peripheral surface () of the inner member () and an inner peripheral surface () of the outer member (), and a lubricating oil is interposed in the radial bearing gap. Further, between the inner member () and the outer member (), sealing gaps (S, S) for maintaining an oil level of the lubricating oil on both axial sides of the radial bearing gap are formed. At least a part of the mounting surface () of the inner member () is made of a metal.

Slide bearing, slide bearing unit with same, and motor with the bearing unit

An inner peripheral surface and a lower end surface of a bearing sleeve made of a sintered metal are each formed into a smooth cylindrical surface or a flat surface that does not have a dynamic pressure generating portion. Thus, a step of forming the dynamic pressure generating portion can be omitted from a manufacturing step of the bearing sleeve, and cost of dies can be markedly reduced. Further, the inner peripheral surface of the bearing sleeve is formed into the smooth cylindrical surface, and hence a radial dynamic pressure generating portion is formed on an outer peripheral surface of a shaft member. However, the outer peripheral surface of the shaft portion is accessible to tools, and hence the radial dynamic pressure generating portion can be formed easily with high accuracy. As a result, accuracy of a radial bearing gap is enhanced so that a bearing rigidity is enhanced.

Fluid dynamic bearing device

Provided is a bearing capable of satisfying demands for cost reduction and further quietness, and stably maintaining high support accuracy. A sliding bearing () includes an inner member () having a mounting surface () with respect to a rotary shaft (), and an outer member () being arranged on a radially outer side of the inner member (). A radial bearing gap is formed between an outer peripheral surface () of the inner member () and an inner peripheral surface () of the outer member (), and a lubricating oil is interposed in the radial bearing gap. Further, between the inner member () and the outer member (), sealing gaps (S, S) for maintaining an oil level of the lubricating oil on both axial sides of the radial bearing gap are formed. At least a part of the mounting surface () of the inner member () is made of a metal.

To increase fixation strength of a bearing sleeve with respect to a bottomed cylindrical housing, a fluid dynamic bearing device () is provided with a bottomed cylindrical housing (), a bearing sleeve () fixed to an inner periphery thereof, and a shaft member () inserted along an inner periphery of the bearing sleeve (). An adhesive pool () is provided between an inner peripheral surface () of a smaller diameter portion () of the housing () and an outer peripheral surface () of the bearing sleeve (), which are opposed to each other. Further, an inner peripheral chamfer () continuous with the adhesive pool () is provided on an inner peripheral portion of the housing (), and a first tapered space () formed between the inner peripheral chamfer () and the bearing sleeve () is sealed with an adhesive ().

Fluid dynamic bearing device and manufacturing method therefor

Easy and precise setting of a predetermined thrust bearing gap is made possible. An axial gaphaving a dimension that is equal to the sum of two thrust bearing gaps is first provided between the flange partof the shaft memberand the bearing member or bearing sleeve. The shaft memberand the bearing sleeveare accommodated inside the housingwith this gap dimension &#x3b4; being kept, and the bearing sleeveis secured to the housing

Method for manufacturing fluid dynamic bearing device

A gap width out of the radial bearing gap is axially differed; a narrow width part which has a relatively smaller gap width in the radial bearing gap is arranged on the side relatively closer to a barycentric position of the rotating body, and a wide width part which has a relatively larger gap width in the radial bearing gap is arranged on a side relatively distant from the barycentric position of the rotating body; and a region facing at least the radial bearing gap of the bearing member is formed to an electroformed part made of deposited metal.

Provided is a fluid dynamic bearing device in which an assembly of a bearing sleeve to a housing is facilitated and which has excellent moment rigidity. A fluid dynamic bearing device () includes radial bearing parts (Rand R) and thrust bearing parts (Tand T). Thrust bearing surfaces (C and D) are respectively provided to first and second step surfaces (and) of a housing (), and the thrust bearing parts (Tand T) are respectively formed between the thrust bearing surfaces (C and D) and end surfaces (and) of seal members (and) provided while protruding to an outer diameter side of a shaft member ().

Fluid dynamic bearing device and method of manufacturing the same

A molding pin () is formed in a sectional shape of being held in contact at two points (contact points are denoted by P') with an imaginary cylindrical surface (C&#x2032;). As a result, an undercut of a fixation hole () is reduced or eliminated, and hence it becomes easier to process a die. Moreover, a corner portion () between a cylindrical surface () and the fixation hole () becomes obtuse, and hence the die becomes less liable to deform and break. Therefore, manufacturing cost of the die can be reduced, and hence cost reduction of the bearing device can be achieved.

Fluid dynamic bearing device, and manufacturing method of bearing member

Fixation strength of a bearing sleeve with respect to a housing is increased so that stable bearing performance can be achieved. A fluid dynamic bearing device () includes a housing () and a bearing sleeve () fixed to an inner periphery of the housing (). The housing () and the bearing sleeve () have therebetween a press-fitting part () at which the housing () and the bearing sleeve () are fixed by press-fitting, and an adhesive-filled part () formed on an opening side with respect to the press-fitting part ().

Fluid dynamic bearing device and process for manufacturing the same

An oil film is formed in a radial bearing clearance of a first radial bearing portion (R) and a second radial bearing portion (R) so as to rotatably support a shaft member (). A bearing sleeve () and the shaft member () are accommodated in a housing (), and the housing () has an inner space filled with a lubricant oil and has an opening sealed by a seal member (). A first seal space (S) is formed by means of an inner peripheral surface () of the seal member (). The housing () and the seal member () are formed through injection molding of a resin.

A fluid dynamic bearing apparatus includes shaft member, housing, sleeve portion, and sealing portions. The housingincludes a straight cylindrical inner circumferential surface with a constant diameter and openings at both axial ends thereof. The sleeve portionis provided separately from the housingand fixed to the inner circumferential surface of the housing. A radial bearing gap is formed between the inner circumferential surfaceof the sleeve portionand the outer circumferential surfaceof the shaft member, and thrust bearing gaps are formed between the end facesof the sealing portionsand the end facesof the sleeve portionopposing these to support the shaft memberin a non-contact manner in the radial direction and in the thrust direction by the hydrodynamic effect of a lubricating oil produced in each bearing gap.

Fluid dynamic bearing apparatus

A protrusion () directed axially downwards is provided at a bottom portion () of a housing (), and an outer peripheral surface () of the protrusion () is fixed to an inner peripheral surface () of a bracket (). When a thrust load is applied to the bottom portion () of the housing (), a part of the load is supported by the bracket () via the protrusion (). Thus, a strength of a boundary portion (P) between a side portion () and the bottom portion () of the housing () increases, making it possible to prevent rupture of the boundary portion (P) due to an excessive thrust load. On the other hand, a wall thickness of the bottom portion () can be made invariable, so it is possible to suppress deformation through molding shrinkage of a thrust bearing surface formed on an inner end surface () of the bottom portion ().

A fluid dynamic bearing device includes a bearing sleeve including a radial bearing surface, a shaft member to be inserted to an inner circumference of the bearing member, and a radial bearing part for non-contact supporting the shaft member in a radial direction by a dynamic pressure action of a fluid generated in a radial bearing gap between the radial bearing surface of the bearing member and an outer circumferential surface of the shaft member. Additionally, a plurality of bearing sleeves are axially arranged, and each bearing sleeve is formed having different axial length with respect to one another.

Peeling-off of an oil-repellent film can be reliably prevented. A fluid dynamic bearing device () includes a shaft member () and first and second flange portions () serving as seal portions fixed to the shaft member (). On outer peripheral sides of the first and second flange portions (), a first seal space (S) and a second seal space (S) are formed, respectively. Oil-repellent films () are provided on end surfaces of the first flange portion () and the second flange portion () separately from a pressure-receiving surface () subjected to pressure at a time of assembly, the end surfaces being exposed to external air.

Growing community of inventors

Kuwana, Japan

Masaharu Hori