Patents by Inventor Rikuro Obara

Rikuro Obara has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7176594
    Abstract: A motor that can prevent damages on the fluid dynamic bearing. A ball is press-fitted into the end surface of the shaft body, and the ball is disposed in such a manner that the tip portion of the ball comes to the higher position with respect to the end surface of the annular body. When the shaft is at rest, the ball abuts against the upper surface of the counter plate, and the end surface of the annular body is brought into a state of being raised from the upper surface of the counter plate, so that the situation in which the end surface of the annular body and the upper surface of the counter plate are brought into almost fully touch each other can be avoided. Therefore, when the operation is started, the circulation speed of a fluid increases and a fluid layer is quickly formed. As a consequent, the fluid circularity blocking action, which could be occurred in the relate art, is avoided, and generation of scratch caused by starting rotation in the tightly sticked state can be positively prevented.
    Type: Grant
    Filed: January 14, 2004
    Date of Patent: February 13, 2007
    Assignee: Minebea Co., Ltd.
    Inventors: Rikuro Obara, Akio Okamiya
  • Patent number: 7168857
    Abstract: The invention provides a special type bearing device that is insusceptible to damage, is light in weight, has a long service life and excellent wear resistance, is insusceptible to the effect of change in temperature, is easy to fabricate, and has little offensiveness towards mating members. Further, the same is capable of sufficiently retaining a lubricant such as oil and grease, and retaining the lubricant for a long period of time without the need of supplying oil during operation, thereby rendering it maintenance-free. That is, the special type bearing device as described above has an axial shaft, a pair of rotating bodies fixedly attached to the shaft, and a supporting body with which the rotating bodies are in contact, wherein any one of the shift, the rotating bodies, and the supporting body is made of RB ceramic or CRB ceramic.
    Type: Grant
    Filed: August 26, 2004
    Date of Patent: January 30, 2007
    Assignee: Minebea Co., Ltd.
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Patent number: 7144932
    Abstract: A synthetic resin composition includes at least one synthetic resin and RBC or CRBC particles dispersed in the resin. A method for preparing a synthetic resin composition includes mixing RBC or CRBC particles with a synthetic resin at a temperature near the melting temperature of the synthetic resin. Preferably, the method of includes the step of kneading the mixture.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: December 5, 2006
    Assignee: Minebea Co., Ltd.
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Patent number: 7000320
    Abstract: A process for manufacturing miniature ball bearings that reduces material loss to improve manufacturing efficiency. The process consists of obtaining an inner and outer ring blank by cutting a first blank, forging the first blank to obtain a final blank, and separating the final blank to form an outer ring blank and an inner ring blank. The outer ring blank has an outer diameter of at most 13 mm. Cutting the first blank is performed by mechanically cutting and machining.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: February 21, 2006
    Assignee: Minebea Co., Ltd.
    Inventor: Rikuro Obara
  • Patent number: 6990738
    Abstract: A process for manufacturing miniature ball bearings that reduces material loss to improve manufacturing efficiency. The process consists of obtaining an inner and outer ring blank by cutting a first blank, forging the first blank to obtain a final blank, and separating the final blank to form an outer ring blank and an inner ring blank. The outer ring blank has an outer diameter of at most 13 mm. Cutting the first blank is performed by press cutting.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: January 31, 2006
    Assignee: Minebea Co., Ltd.
    Inventor: Rikuro Obara
  • Patent number: 6965493
    Abstract: A shaft secured to a hub is inserted and rotatably supported in a sleeve secured to a base. A dynamic pressure groove is formed in the inner peripheral surface of the sleeve, and lubricant is sealed between the shaft and the sleeve. The rotation of the shaft causes dynamic pressure to generate in the lubricant due to the dynamic pressure groove, supporting the shaft floatingly. The crystallized-glass sleeve allows heat generated in a coil to be hardly transferred to the shaft, thereby reducing the variations in the clearance between the shaft and the sleeve due to temperature changes to a minimum in cooperation with the crystallized-glass sleeve with a low thermal expansion coefficient. Finishing accuracy of the bearing surface can be improved by chemical polishing. Consequently, the rotation accuracy can be improved and the leakage of lubricant due to the variations in the clearance can be prevented.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: November 15, 2005
    Assignee: Minebea Co., Ltd.
    Inventor: Rikuro Obara
  • Publication number: 20050198917
    Abstract: A tile is made of a fire-resistant ceramic, which is obtained by mixing and kneading defatted bran obtained from rice bran and a thermosetting resin, primarily baking the resulting mixture in an inert gas at 700° C. to 1000° C., crushing the resulting product into carbonized powder, mixing and kneading the carbonized powder with a ceramic powder, a solvent and, optionally, a binder to provide a plasticized mixture (ceramic-solvent mixture), pressure-forming the mixture at a compression pressure of 10 MPa to 100 MPa, and heat-treating the resulting compact again in an atmosphere of an inert gas at 500 to 1400° C.
    Type: Application
    Filed: March 8, 2005
    Publication date: September 15, 2005
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Patent number: 6916160
    Abstract: The object of the present invention is to provide a blower in which electrical components such as printed circuit board or electronic parts are isolated from the wind flowing through the blower to protect these components from moisture, dirt, dusts, or other harmful gas or substance contained in the wind, and to prevent the degradation of the insulating property such as the electric insulation or dielectric strength.
    Type: Grant
    Filed: March 13, 2001
    Date of Patent: July 12, 2005
    Assignee: Minebea Kabushiki-Kaisha
    Inventor: Rikuro Obara
  • Patent number: 6855214
    Abstract: An anti-friction bearing is provided which is low in vibration and excellent in quietness. The anti-friction bearing has rolling elements provided in inner and outer ring raceway grooves, which are made of martensitic stainless steel composed of 0.60 to 0.75 percent of carbon by weight, 10.5 to 13.5 percent of chromium by weight, 1.0 percent or less of silicon by weight and 0.3 to 0.8 percent of manganese by weight, the remainder of the composition being iron and inevitably introduced impurities, having a hardness of HRC 58 or higher, containing eutectic carbide particles of 10 microns or less in diameter, having oxygen and titanium concentrations of 10 ppm or less respectively, and less than 10 percent by volume of retained austenite.
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: February 15, 2005
    Inventors: Rikuro Obara, Yutaka Daikuhara
  • Patent number: 6855279
    Abstract: The invention provides a weather-resistant exterior building material which has been unavailable in the past with respect to characteristics of keeping harmful insects such as white ants, and so forth away therefrom, light weight, a long service life, insusceptibility to variation in temperature, hygroscopicity, and easiness in fabrication, and an exterior article made up of the same. The weather-resistant exterior building material according to the invention makes use of a compact formed of RB ceramic, CRB ceramic, or fire-resistant CRB ceramic.
    Type: Grant
    Filed: April 18, 2002
    Date of Patent: February 15, 2005
    Assignee: Minebea Co., Ltd.
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Publication number: 20050028349
    Abstract: A spindle motor is formed so as to support a pivot of a rotor by a pair of open bearings. The open bearings thus constructed will be less expensive and simple structures, so that a manufacturing cost thereof is reduced compared to a conventional spindle motor using a pair of ball bearings with shields. Accordingly, a low-cost spindle motor can be provided.
    Type: Application
    Filed: July 8, 2003
    Publication date: February 10, 2005
    Applicant: Minebea Co., Ltd.
    Inventors: Rikuro Obara, Kenji Fukunaga
  • Publication number: 20050032939
    Abstract: According to the invention, a synthetic resin composition having a desirable a low coefficient of friction when submersed in a liquid is provided. In addition, a method of making a low friction bearing for use under liquid is provided as well as a low friction bearing or use underwater. According to the invention, a synthetic resin composition with lubricative underwater properties is provided. A powder preferably a fine powder of a RBC, CRBC or both are uniformly dispersed in a synthetic resin. Desirably the weight ratio between RBC or CRBC powders and the synthetic resin is 30:90 to 70:10.
    Type: Application
    Filed: August 28, 2004
    Publication date: February 10, 2005
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Publication number: 20050031241
    Abstract: A double-row ball bearing with a preload application structure including an axle and a sleeve surrounding the axle. At least two rows of bearing balls are disposed between the axle and the sleeve. An inner bearing ring is slidably mounted on the axle such that at least one of the two rows of bearing balls is set between the inner bearing ring and the sleeve. The second row of bearing balls is then set directly between the axle and the sleeve. A resilient member is connected to an external side surface of the inner bearing ring, and a preload applying member is connected to the resilient member. The preload applying member applies a preload to the inner bearing ring by increasing pressure on the resilient member. When an appropriate preload is achieved, the preload applying member is fixed to the axle.
    Type: Application
    Filed: August 12, 2004
    Publication date: February 10, 2005
    Applicant: Minebea Co., Ltd.
    Inventor: Rikuro Obara
  • Publication number: 20050025406
    Abstract: The invention provides a special type bearing device that is insusceptible to damage, is light in weight, has a long service life and excellent wear resistance, is insusceptible to the effect of change in temperature, is easy to fabricate, and has little offensiveness towards mating members. Further, the same is capable of sufficiently retaining a lubricant such as oil and grease, and retaining the lubricant for a long period of time without the need of supplying oil during operation, thereby rendering it maintenance-free. That is, the special type bearing device as described above has an axial shaft, a pair of rotating bodies fixedly attached to the shaft, and a supporting body with which the rotating bodies are in contact, wherein any one of the shift, the-rotating bodies, and the supporting body is made of RB ceramic or CRB ceramic.
    Type: Application
    Filed: August 26, 2004
    Publication date: February 3, 2005
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Patent number: 6799893
    Abstract: The invention provides a special type bearing device that is insusceptible to damage, is light in weight, has a long service life and excellent wear resistance, is insusceptible to the effect of change in temperature, is easy to fabricate, and has little offensiveness towards mating members. Further, the same is capable of sufficiently retaining a lubricant such as oil and grease, and retaining the lubricant for a long period of time without the need of supplying oil during operation, thereby rendering it maintenance-free. That is, the special type bearing device as described above has an axial shaft, a pair of rotating bodies fixedly attached to the shaft, and a supporting body with which the rotating bodies are in contact, wherein any one of the shift, the rotating bodies, and the supporting body is made of RB ceramic or CRB ceramic.
    Type: Grant
    Filed: February 19, 2002
    Date of Patent: October 5, 2004
    Assignee: Minebea Co., Ltd.
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Patent number: 6794774
    Abstract: A spindle motor of the present invention is capable of keeping its ball (5a, 5b)'s pre-load constant, because a sleeve (6) is capable of being resiliently deformed due to its resiliency, and therefore capable of constantly keeping a pre-load applied to the balls (5a, 5b) from inner and inner ring raceways of inner and outer rings (3a, 4a, 3b, 4b) of ball bearings (3, 4). In this motor, a rotor hub (7) has an axial center bore (8). This bore (8) is provided with: a large-diameter bore portions in its opposite axial ends; and, a small-diameter bore portion (8a) axially interposed between the large-diameter bore portions. An inner diameter of the small-diameter bore portion (8a) is smaller than an outer diameter of the sleeve (6).
    Type: Grant
    Filed: December 12, 2002
    Date of Patent: September 21, 2004
    Assignee: Minebea Kabushiki-Kaisha
    Inventors: Rikuro Obara, Hiroshi Yoshikawa
  • Patent number: 6787075
    Abstract: A method of making a low friction bearing for use when immersed in a liquid particularly water is provided comprising a synthetic resin composition which includes powders of a rice bran ceramic, carbon rice bran ceramic or both which are uniformly dispersed in a synthetic resin. The weight ratio between the RBC or CRBC powders and the synthetic resin is 30:90 to 70:10.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: September 7, 2004
    Assignee: Minebea Co., Ltd.
    Inventors: Kazuo Hokkirigawa, Rikuro Obara
  • Publication number: 20040160137
    Abstract: A motor that can prevent damages on the fluid dynamic bearing. A ball is press-fitted into the end surface of the shaft body, and the ball is disposed in such a manner that the tip portion of the ball comes to the higher position with respect to the end surface of the annular body. When the shaft is at rest, the ball abuts against the upper surface of the counter plate, and the end surface of the annular body is brought into a state of being raised from the upper surface of the counter plate, so that the situation in which the end surface of the annular body and the upper surface of the counter plate are brought into almost fully touch each other can be avoided. Therefore, when the operation is started, the circulation speed of a fluid increases and a fluid layer is quickly formed. As a consequent, the fluid circularity blocking action, which could be occurred in the relate art, is avoided, and generation of scratch caused by starting rotation in the tightly sticked state can be positively prevented.
    Type: Application
    Filed: January 14, 2004
    Publication date: August 19, 2004
    Applicant: Minebea Co., Ltd.
    Inventors: Rikuro Obara, Akio Okamiya
  • Patent number: 6777360
    Abstract: A ceramic material suitable for use in production of paving tiles, construction tiles, flooring in offices, flooring in machinery plants and so forth is obtained by a method comprising steps of mixing defatted bran derived from rice bran with a thermosetting resin before kneading, subjecting a kneaded mixture thus obtained to a primary firing in an inert gas at a temperature in a range of 700 to 1000° C., pulverizing the kneaded mixture after the primary firing into carbonized powders, kneading the carbonized powders with which ceramic powders, a solvent, and a binder as desired are mixed into a plastic workpiece (kneaded mass), pressure-forming the plastic workpiece at pressure in a range of 10 to 100 MPa, and subjecting a formed plastic workpiece thus obtained again to firing in an inert gas atmosphere at a temperature in a range of 100 to 1400° C.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: August 17, 2004
    Assignee: Minebea Co., Ltd.
    Inventors: Kazuo Hokkirigawa, Rikuro Obara, Motoharu Akiyama
  • Publication number: 20040136842
    Abstract: An apparatus to render the shield of a bail bearing unnecessary and to improve the lubricity inside a fan motor is presented. A bearing housing is integrally formed with a base of the fan motor, and a shield part is formed at one end of the bearing housing. A ball bearing, spacer and sleeve bearing are set inside from the other end of the bearing housing, and these are fixed in place by pressing in a retainer cap. The interior of the bearing housing is then shielded at each end by the shield part and the retainer cap, making the need for a shielded ball bearing unnecessary. A rotational shaft, to which a rotor and impeller are attached, is supported by the ball bearing and the sleeve bearing. Inside the bearing housing, lubricating oil passes back and forth between the ball bearing and sleeve bearing, thereby enabling the elimination of insufficiencies in lubricating oil, and improving lubricity.
    Type: Application
    Filed: July 2, 2003
    Publication date: July 15, 2004
    Applicant: Minebea Co., Ltd.
    Inventors: Rikuro Obara, Kaoru Matsumoto