Patents by Inventor Daigo NAKAJIMA

Daigo NAKAJIMA 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: 11915720
    Abstract: The spindle motor includes; a shaft including a shaft portion and a flange portion, the shaft portion having a columnar shape extending in an axial direction, the shaft portion including a shaft end portion, the flange portion being provided at the shaft end portion and receiving a load in the axial direction; and a bearing sleeve rotatably supporting the shaft, the bearing sleeve having a tubular shape including a sleeve end portion having a large-diameter recess part formed in the axial direction. The shaft is a member formed of a copper alloy containing from 0.5 mass percent to 1.5 mass percent of silicon and from 0.5 mass percent to 3.0 mass percent of manganese, and the member includes the shaft portion and the flange portion integrated with one another.
    Type: Grant
    Filed: March 2, 2023
    Date of Patent: February 27, 2024
    Assignee: MINEBEA MITSUMI Inc.
    Inventors: Hideaki Showa, Daigo Nakajima
  • Publication number: 20230298625
    Abstract: The spindle motor includes; a shaft including a shaft portion and a flange portion, the shaft portion having a columnar shape extending in an axial direction, the shaft portion including a shaft end portion, the flange portion being provided at the shaft end portion and receiving a load in the axial direction; and a bearing sleeve rotatably supporting the shaft, the bearing sleeve having a tubular shape including a sleeve end portion having a large-diameter recess part formed in the axial direction. The shaft is a member formed of a copper alloy containing from 0.5 mass percent to 1.5 mass percent of silicon and from 0.5 mass percent to 3.0 mass percent of manganese, and the member includes the shaft portion and the flange portion integrated with one another.
    Type: Application
    Filed: March 2, 2023
    Publication date: September 21, 2023
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA
  • Patent number: 11118628
    Abstract: A fluid dynamic bearing device prevents an oleophobic agent from wetting and spreading to a tapered seal portion, including lubricating oil C filled in a condition in which the oil is separated sandwiching a separator portion 240 holding a gas layer arranged between two conical bearing members 201, and two primary tapered seal portions 230 each connecting to one of both ends along an axial direction of the separator portion 240, wherein width in a radial direction of the two primary tapered seal portion 230 decreases as each approaches toward the two conical bearing members 201, a gas-liquid interface of the lubricating oil C is located each of the two primary tapered seal portions 230, an oleophobic agent blocking portion 250 is arranged at each of both ends in an axial direction of the separator portion 240, a separator central portion 244 is arranged between the oleophobic agent blocking portions 250 of the separator portions 240, and an oleophobic coating is formed at least at the separator central portio
    Type: Grant
    Filed: November 3, 2020
    Date of Patent: September 14, 2021
    Assignee: MINEBEA MITSUMI INC.
    Inventors: Hideaki Showa, Daigo Nakajima, Kazuo Ota
  • Publication number: 20210140481
    Abstract: A fluid dynamic bearing device prevents an oleophobic agent from wetting and spreading to a tapered seal portion, including lubricating oil C filled in a condition in which the oil is separated sandwiching a separator portion 240 holding a gas layer arranged between two conical bearing members 201, and two primary tapered seal portions 230 each connecting to one of both ends along an axial direction of the separator portion 240, wherein width in a radial direction of the two primary tapered seal portion 230 decreases as each approaches toward the two conical bearing members 201, a gas-liquid interface of the lubricating oil C is located each of the two primary tapered seal portions 230, an oleophobic agent blocking portion 250 is arranged at each of both ends in an axial direction of the separator portion 240, a separator central portion 244 is arranged between the oleophobic agent blocking portions 250 of the separator portions 240, and an oleophobic coating is formed at least at the separator central portio
    Type: Application
    Filed: November 3, 2020
    Publication date: May 13, 2021
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA, Kazuo OTA
  • Patent number: 10938270
    Abstract: A spindle motor according to one aspect of the present disclosure includes: a hub; a yoke; a rotor magnet; and a stator. The hub is formed in a cup shape having a hub cylindrical part extending in an axial direction and a disk part extending radially inward from an end of the hub cylindrical part. The yoke being arranged on radially inward of the hub is formed in an annular shape having a yoke cylindrical part facing the hub cylindrical part and a yoke flange part facing the disk part and extending radially inward from the one end of the hub cylindrical part. The disk part includes an adhesive part with the yoke flange part being fixed via an adhesive and a peripheral groove being formed on radially outward of the adhesive part. The adhesive is not present on radially outward of the peripheral groove, and the hub cylindrical part and the yoke cylindrical part do not contact each other.
    Type: Grant
    Filed: April 2, 2019
    Date of Patent: March 2, 2021
    Assignee: MINEBEA MITSUMI INC.
    Inventors: Daigo Nakajima, Hideaki Showa, Daisuke Ito
  • Patent number: 10825476
    Abstract: A spindle motor includes a base plate on which a through hole is formed, a stator assembly provided at an top side of the base plate having a stator core with stator windings, a circuit board provided at the bottom side of the base plate and to which a lead wire of the stator windings drawn from the through hole to the bottom side is connected. An insulating cover sheet is provided at the top side of the base plate for covering the through hole, the insulating cover sheet being passed through by the lead wire, and a sealing material filling the through hole. The insulating cover sheet has a wire hole and an air vent part communicating with the through hole, wherein the air vent part faces at least a portion of an inside opening of the through hole. The wire hole and the air vent part are separated from each other or are connected to form a single opening.
    Type: Grant
    Filed: November 6, 2019
    Date of Patent: November 3, 2020
    Assignee: MINEBEA MITSUMI INC.
    Inventors: Sendy Hanzel, Tobias Imberger, Christoph Fluck, Hideaki Showa, Daigo Nakajima, Tetsuo Kitamura
  • Patent number: 10755740
    Abstract: A spindle motor includes a base plate in which a through hole is formed, a stator core that is provided inside the base plate and is wound with a coil, and a circuit board that is provided outside the base plate and to which a conducting wire of the coil drawn out to outside through the through hole is connected, wherein the through hole includes an inner opening that opens inward of the base plate, an outer opening that opens outward of the base plate, and an intermediate portion having a cylindrical shape that is provided between the inner opening and the outer opening, an enlarged opening is formed to be connected to the outer opening, the enlarged opening is offset to extend toward a side where the circuit board is not present, and the through hole is sealed with a sealing material.
    Type: Grant
    Filed: September 26, 2019
    Date of Patent: August 25, 2020
    Assignee: MINEBEA MITSUMI INC.
    Inventors: Hideaki Showa, Daigo Nakajima, Tetsuo Kitamura
  • Publication number: 20200143832
    Abstract: A spindle motor includes a base plate on which a through hole is formed, a stator assembly provided at an top side of the base plate having a stator core with stator windings, a circuit board provided at the bottom side of the base plate and to which a lead wire of the stator windings drawn from the through hole to the bottom side is connected. An insulating cover sheet is provided at the top side of the base plate for covering the through hole, the insulating cover sheet being passed through by the lead wire, and a sealing material filling the through hole. The insulating cover sheet has a wire hole and an air vent part communicating with the through hole, wherein the air vent part faces at least a portion of an inside opening of the through hole. The wire hole and the air vent part are separated from each other or are connected to form a single opening.
    Type: Application
    Filed: November 6, 2019
    Publication date: May 7, 2020
    Inventors: Sendy HANZEL, Tobias IMBERGER, Christoph FLUCK, Hideaki SHOWA, Daigo NAKAJIMA, Tetsuo KITAMURA
  • Publication number: 20200105299
    Abstract: A spindle motor includes a base plate in which a through hole is formed, a stator core that is provided inside the base plate and is wound with a coil, and a circuit board that is provided outside the base plate and to which a conducting wire of the coil drawn out to outside through the through hole is connected, wherein the through hole includes an inner opening that opens inward of the base plate, an outer opening that opens outward of the base plate, and an intermediate portion having a cylindrical shape that is provided between the inner opening and the outer opening, an enlarged opening is formed to be connected to the outer opening, the enlarged opening is offset to extend toward a side where the circuit board is not present, and the through hole is sealed with a sealing material.
    Type: Application
    Filed: September 26, 2019
    Publication date: April 2, 2020
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA, Tetsuo KITAMURA
  • Patent number: 10476340
    Abstract: A spindle motor includes a base plate to which a shaft is fixed, an annular stator core that is fixed to the base plate and is wound with a plurality of stator coils, and a rotor member that is attached in a rotatable state to the shaft and includes an inner sleeve portion facing an inner peripheral side of the stator core with an inner clearance and an outer sleeve portion facing an outer peripheral side of the stator core with an outer clearance, an annular groove is formed on an outer periphery of the inner sleeve portion, and the annular groove overlaps with the plurality of stator coils as viewed from a direction perpendicular to the shaft.
    Type: Grant
    Filed: October 24, 2017
    Date of Patent: November 12, 2019
    Assignee: MINEBEA MITSUMI INC.
    Inventors: Hideaki Showa, Daigo Nakajima
  • Publication number: 20190305635
    Abstract: A spindle motor according to one aspect of the present disclosure includes: a hub; a yoke; a rotor magnet; and a stator. The hub is formed in a cup shape having a hub cylindrical part extending in an axial direction and a disk part extending radially inward from an end of the hub cylindrical part. The yoke being arranged on radially inward of the hub is formed in an annular shape having a yoke cylindrical part facing the hub cylindrical part and a yoke flange part facing the disk part and extending radially inward from the one end of the hub cylindrical part. The disk part includes an adhesive part with the yoke flange part being fixed via an adhesive and a peripheral groove being formed on radially outward of the adhesive part. The adhesive is not present on radially outward of the peripheral groove, and the hub cylindrical part and the yoke cylindrical part do not contact each other.
    Type: Application
    Filed: April 2, 2019
    Publication date: October 3, 2019
    Inventors: Daigo NAKAJIMA, Hideaki SHOWA, Daisuke ITO
  • Patent number: 10393171
    Abstract: A fluid dynamic pressure bearing includes a conical bearing member having a conical bearing surface forming a first gap between a member constituting the rotor. A second gap connected to one end of the first gap and provided over the entire periphery of the shaft is formed between the conical bearing member and the shaft. A tapered seal portion is formed between the conical bearing member and the rotor. The conical bearing member is provided with a circulation hole that communicates the second gap and the tapered seal portion. The circulation hole communicates to another end of the first gap through a part of the tapered seal portion, so that the circulation hole and the other end of the first gap are spaced apart.
    Type: Grant
    Filed: March 13, 2018
    Date of Patent: August 27, 2019
    Assignee: MINEBEA MITSUMI INC.
    Inventors: Hideaki Showa, Daigo Nakajima, Kazuo Ota
  • Publication number: 20180266482
    Abstract: A fluid dynamic pressure bearing includes a conical bearing member having a conical bearing surface forming a first gap between a member constituting the rotor. A second gap connected to one end of the first gap and provided over the entire periphery of the shaft is formed between the conical bearing member and the shaft. A tapered seal portion is formed between the conical bearing member and the rotor. The conical bearing member is provided with a circulation hole that communicates the second gap and the tapered seal portion. The circulation hole communicates to another end of the first gap through a part of the tapered seal portion, so that the circulation hole and the other end of the first gap are spaced apart.
    Type: Application
    Filed: March 13, 2018
    Publication date: September 20, 2018
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA, Kazuo OTA
  • Publication number: 20180123417
    Abstract: A spindle motor includes a base plate to which a shaft is fixed, an annular stator core that is fixed to the base plate and is wound with a plurality of stator coils, and a rotor member that is attached in a rotatable state to the shaft and includes an inner sleeve portion facing an inner peripheral side of the stator core with an inner clearance and an outer sleeve portion facing an outer peripheral side of the stator core with an outer clearance, an annular groove is formed on an outer periphery of the inner sleeve portion, and the annular groove overlaps with the plurality of stator coils as viewed from a direction perpendicular to the shaft.
    Type: Application
    Filed: October 24, 2017
    Publication date: May 3, 2018
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA
  • Publication number: 20170288494
    Abstract: A spindle motor has a base plate, a stator core fixed to the base plate, a rotor member rotatable with respect to the base plate, a rotor magnet facing the stator core in a radial direction and fixed to the rotor member and a ring-shaped magnetic attractive plate attached to the base plate bottom surface facing the rotor magnet in an axial direction to generate a magnetic attracting force between the rotor magnet and the magnetic attractive plate. A ring-shaped wall surface is on the base plate bottom surface. At least one of an outer and inner circumference of the ring-shaped magnetic attractive plate has a polygonal shape formed of linear parts and corner parts. In a state in which at least one of the outer and inner circumferences having the polygonal shape contacts the ring-shaped wall surface, the ring-shaped magnetic attractive plate is adhesively fixed to the base plate.
    Type: Application
    Filed: March 29, 2017
    Publication date: October 5, 2017
    Applicant: MINEBEA MITSUMI INC.
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA, Naoyuki KONDO
  • Publication number: 20160172924
    Abstract: A motor includes: a base including a holder portion; a shaft supporting member fitted inside the holder portion and fixed onto an inner circumferential surface of the holder portion; a shaft supported by the shaft supporting member; a rotor assembly rotatably supported with respect to the shaft supporting member via the shaft; and a stator assembly arranged on an outer circumferential portion of the holder portion. An adhesive groove on the base side and an adhesive groove on the shaft supporting member side, to which an adhesive is applied, are formed respectively on the inner circumferential surface of the holder portion and on an outer circumferential surface of the shaft supporting member facing the inner circumferential surface of the holder portion, and the adhesive grooves on the base side and on the shaft supporting member side are disposed to face each other at least in part.
    Type: Application
    Filed: December 8, 2015
    Publication date: June 16, 2016
    Inventors: Hideaki SHOWA, Daigo NAKAJIMA, Naoyuki KONDO