Sankyo Seiki Mfg. Co., Ltd

Kabushiki Kaisha Sankyo Seiki Seisakusho

Taiho Industries Co., Ltd.

Shikoku Chemicals Corporation

Masamichi Hayakawa

Masato Gomyo

Hideki Kanebako

Tamotsu Nose

Toshihiro Kobayashi

Kazushi Miura

Michiaki Takizawa

Hisaya Nakagawa

Hiromasa Marumo

Kazuya Shimizu

Toshihiko Miyakoshi

Yuusuke Matsumura

Masuhiro Onoyama

Katsumi Nagano

Ikuo Kasuga

Kenji Hanabusa

Hirofusa Shirai

Yasushi Mizusaki

Hironori Kurosawa

Hajime Hata

Tokuhisa Tsutsui

Arihiro Yonezawa

Shogo Ogawa

A dynamic pressure bearing apparatus comprises a rotary shaft, a sintered oil retaining bearing rotatably supporting the rotary shaft, the sintered oil retaining bearing having an interior surface defining an internal surface configuration for generating dynamic pressure to thereby form a dynamic pressure bearing between the rotary shaft and the sintered oil retaining bearing. The internal surface of the sintered oil retaining bearing comprises in a peripheral direction thereof, a minimum-gap section, a large-gap section and a separation groove section. The minimum-gap section has the minimum gap between the rotary shaft and the internal surface of the sintered oil retaining bearing. The large-gap section is continuous to the minimum-gap section, and has a larger gap between the rotary shaft and the sintered oil retaining bearing than that at the minimum-gap section to thereby increase pressure of lubrication oil that is present between the rotary shaft and the sintered oil retaining bearing toward the minimum-gap section. The separation groove section is provided between the large-gap section and the minimum-gap section. The separation groove section has a gap greater than that of the large-gap section. The minimum-gap section and the large-gap section define a dynamic pressure bearing surface section. The minimum-gap section is located at a predetermined angular position with respect to the separation groove section in a manner that a ratio between an arc angle defined by the dynamic pressure bearing surface section and the predetermined angular position of the minimum-gap section is 1:0 through 0.2. Furthermore, a maximum gap in the large-gap section with respect to the rotary shaft is two times or less greater than a minimum gap at the minimum-gap section with respect to the rotary shaft.

Dynamic pressure bearing apparatus

A fluid sealing device for use in a motor having a fluid bearing for mounting a frame to a shaft. The fluid sealing device includes a bearing fluid reservoir, a sealing plate, and a bearing fluid absorbing pad. The bearing fluid reservoir is positioned at one axial end of the fluid bearing. The sealing plate is mounted on the frame and positioned axially outward of the bearing fluid reservoir. The sealing plate has an inner edge extending radially toward the shaft to provide a sealing space between the shaft and the sealing plate. A bearing fluid absorbing pad is mounted axially inward from the sealing plate. A capture space is provided between the bearing fluid absorbing pad, sealing plate and reservoir such that the bearing fluid absorbing pad is exposed to the reservoir.

Fluid sealing device for use with a motor for rotating a disc drive

A hydrodynamic bearing apparatus comprises two hydrodynamic bearing sections which have a shaft member, a bearing member fit to the shaft member with a predetermined space therein, lubricants filling the space between the shaft member and the bearing member, and which are separately placed in the axial direction of the shaft member. The lubricants of the two hydrodynamic bearing sections are separated from each other by an air layer. The lubricants are pressured by hydrodynamic generating grooves formed on the hydrodynamic bearing sections such that the shaft member and the bearing member are rotatably supported in relation to each other. The hydrodynamic generating grooves separately formed on the two hydrodynamic bearing sections are formed into an unbalanced shape such that the lubricants are moved in a predetermined direction to correct the slope of the shaft member and the bearing member when rotation is suspended. Capillary sealing sections are formed in continuation to end sections of each of the two hydrodynamic bearing sections to sustain the lubricants by capillarity. The maximum amount of the lubricant in one of the capillary sealing sections, which is located downstream in the moving direction of the lubricants, is established to be larger than the moving amount of the lubricants.

Hydrodynamic bearing apparatus

The dynamic pressure bearing device is structured such that the pores of porous material as they are are disposed in the surfaces thereof forming the negative pressure cancel portions,and a lubricating fluid is supplied to the negative pressure generating areas thereof through the pores of the negative pressure cancel portions,, whereby, even if recess-shaped grooves forming the negative pressure cancel portions,are formed shallow in depth and wide in width, or even if such grooves themselves are not formed at all, the dynamic pressure bearing device is able to fulfill its negative pressure cancel function in a sufficient manner. This makes it possible to eliminate the need for provision of the conventional recess-shaped grooves which are formed deep and narrow, thereby eliminating the need to execute an expensive operation such as a cutting operation or the like, so that the negative pressure cancel portions,can be formed at a low cost by inexpensive means such as by molding or the like.

Dynamic pressure bearing device and method for manufacturing same

A dynamic-pressure fluid bearing comprises bearing parts formed by a pair of dynamic-pressure surfaces. One of the dynamic-pressure surfaces of the bearing parts is a polyamideimide coating thicker than 3 .mu.m and the other surface is metal. The bearing is particularly applicable to driving motors for polygon mirrors. In addition, a so-called particle removing function is added to one or more of the surfaces of the bearing parts or a position nearby that causes easier removal of dust and other particles accumulated on the parts.

Dynamic-pressure fluid bearing

A gas dynamic pressure bearing apparatus comprises a fixed shaft, a bearing member which is positioned opposite from the fixed shaft and at least a radial gas dynamic pressure bearing portion and a thrust gas dynamic pressure bearing portion which are positioned in a space between the fixed shaft and the bearing member. Dynamic pressure generating means are included for pressurizing gas in the radial gas dynamic pressure bearing portion and the thrust gas dynamic pressure bearing portion such that dynamic pressure action is generated. The bearing member is rotatably supported in relation to the fixed shaft by means of the pressurizing action such that rotational driving is performed by a predetermined motor. The radial gas dynamic pressure bearing portion and the thrust gas dynamic pressure bearing portion are structured such that gas is sealed from the space around the motor by a space sealing means and that gas flows from one side to other. The flowing gas is circulated between the radial gas dynamic pressure bearing portion and the thrust gas dynamic pressure bearing portion through a gas circulation path. A gas passage is formed on the fixed shaft such that the gas circulation path is connected to the outer end of the fixed shaft. Dust collecting means is formed in one of the gas circulation and the gas passage.

Gas dynamic pressure bearing apparatus

A sealing device for use in a motor. The motor, which maintains a shaft: and a frame that are interconnected by a bearing, includes a magnetic-fluid-seating device and a collecting device. The magnetic-fluid-sealing device seals the bearing with a magnetic fluid to prevent particles and fluids from escaping the bearing, whereas, the collecting device collects any particles and fluids which may escape the magnetic-fluid-sealing device.

Sealing device for use in a motor

A hydrodynamic bearing apparatus which includes at least two hydrodynamic bearing sections for rotatably supporting a shaft member and a cylindrical member, where the bearing sections constitute a continuous bearing clearance. A hydrodynamic pressure generating portion is provided for generating a hydrodynamic pressure in a lubricant which is filled in the bearing clearance. One hydrodynamic generating portion is shaped asymmetrically to move the lubricant in one direction. Two capillary sealing sections are also provided. One capillary sealing section is positioned downstream in a moving direction of the lubricant and is configured such that the lubricant moves by a predetermined amount to cancel a differential pressure which is generated at the hydrodynamic bearing sections.

A hydrodynamic bearing apparatus for use in a spindle motor. The bearing includes at least two hydrodynamic bearing sections for supporting a rotary member with respect to a fixed member, a hydrodynamic pressure generating mechanism, a space between the two hydrodynamic bearing sections, a lubricant, two capillary sealing sections, and a lubricant reservoir. In the hydrodynamic bearing apparatus, the hydrodynamic pressure generating mechanism is positioned at the hydrodynamic bearing sections, and the capillary sealing section of the two capillary sealing sections has a space capacity which allows for an increased amount of lubricant. The lubricant is moved by a predetermined amount in one direction by a differential pressure generated at the hydrodynamic bearing sections when the rotary member rotates.

A motor having a dynamic pressure bearing device equipped with a rotor having a driving coil or a driving magnet, and a stator having the other of the driving coil or the driving magnet, the dynamic pressure bearing device comprising a shaft fixed to the rotor or the stator and having a dynamic pressure surface on its outer surface, a bearing body fixed to the other of the rotor or stator and having a dynamic pressure surface on its inner surface which is positioned to circumferentially confront the outer surface of the shaft body, a dynamic pressure generating groove formed on at least one side of both the dynamic pressure surfaces, and a lubricating fluid in which magnetic particles are dispersed in a base oil solvent containing an amine anti-gelling agent interposed between both of the dynamic pressure surfaces.

Motor having dynamic pressure bearing device

A hydrodynamic bearing apparatus comprises at least two hydrodynamic bearing units which rotatably support a rotation member against a fixed member by hydrodynamic pressure of a lubricant filled in a bearing space. A thrust plate is adhesively bonded on one of the rotation member and fixed member to support the rotation member in an axial direction. The thrust plate and rotation member or fixed member form a junction. A mechanical bonding device bonds the thrust plate onto one of the rotation member and fixed member. A sealing agent prevents the lubricant from leaking from the junction between the thrust plate and the rotation member or fixed member. The sealing agent fills a space that communicates with the junction.

Hydrodynamic bearing apparatus and method for manufacturing same

A fluid bearing unit includes a shaft; a bearing; bearing fluid arranged between a shaft and a bearing which are rotatably engaged with each other so that they can be relatively rotated so as to generate dynamic pressure in the bearing fluid, wherein at least one of the bearing and the member for fixing the bearing unit is made of iron alloy having the volumetric magnetostriction of which acts to cancel the thermal expansion so as to become the coefficient of linear expansion thereof lower than that of the shaft.

Fluid bearing unit and manufactured method thereof

A lubricating fluid composition for dynamic pressure bearings which supports a shaft by dynamic pressure, said lubricating fluid composition comprising fine magnetic particles dispersed in a base oil solvent, to which solvent is added an amine anti-gelling agent.

Lubricating fluid composition for dynamic pressure bearing

A lubricating fluid composition for dynamic pressure bearings which supports the shaft of the bearing by dynamic pressure, wherein the lubricating fluid composition comprises fine magnetic particles dispersed in a base oil solvent which comprises a hydrogenated poly-.alpha.-olefin (PAO) and a polyol ester.

A polyarylene sulfide resin composition having an excellent fluidability and a good moldability is disclosed. The resin composition is useful as a material for an optical pick-up part which has a high reliability and a high tenacity and does not generate deviation of an optical axis with changes in environmental conditions such as temperature and humidity. The polyarylene sulfide resin composition comprises, as main components, a polyarylene sulfide resin, a fibrous filler and a particulate filler, and, optionally, a silane coupling agent and an alicyclic hydrocarbon.

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Nagano, Japan

Masamichi Hayakawa