Patents by Inventor Yoshihiko Yamagishi

Yoshihiko Yamagishi 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: 6047460
    Abstract: A method of manufacturing a permanent magnet rotor comprising a rotor yoke (2) of a rotor (1) which is formed by laminating a large number of steel sheets (4), (14), (24), (34) and (44), has 2n times (n is a positive integer) of magnetic poles (5) on the outer periphery, has slots (6) at the bases of all or every other magnetic poles at a substantially equal distance from a rotatable shaft hole (7), and has permanent magnets (3) for a field inserted into the slots, and a method for producing it. It has a structure that the permanent magnets for the field are prevented from coming out, or the permanent magnets for the field have their faces treated in order to improve the safety and reliability of the permanent magnet rotor.
    Type: Grant
    Filed: May 27, 1997
    Date of Patent: April 11, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Takashi Nagate, Akihito Uetake, Yoshihiko Yamagishi
  • Patent number: 6034458
    Abstract: A DC brushless motor 3 is provided which comprises armature 31 and rotor 32. Rotor 32 is provided with a rotor yoke that has four main poles 321 on its periphery. Slots with a radial-direction size of L.sub.m are formed on main poles 321 of the rotor yoke. Magnetic-field permanent magnet 323 with an approximate thickness of L.sub.m is embedded in each slot 322, such that the radial-direction size L.sub.m of slot 322 and the air gap length L.sub.g of the air gap formed between rotor 32 and armature 31 satisfy the relationship 0<L.sub.m +L.sub.g .ltoreq.2 mm.
    Type: Grant
    Filed: September 4, 1998
    Date of Patent: March 7, 2000
    Assignee: Seiko Epson Corporation
    Inventors: Akihito Uetake, Yoshihiko Yamagishi
  • Patent number: 5844344
    Abstract: A DC brushless motor 3 is provided which comprises armature 31 and rotor 32. Rotor 32 is provided with a rotor yoke that has four main poles 321 on its periphery. Slots with a radial-direction size of L.sub.m are formed on main poles 321 of the rotor yoke. Magnetic-field permanent magnet 323 with an approximate thickness of L.sub.m is embedded in each slot 322, such that the radial-direction size L.sub.m of slot 322 and the air gap length L.sub.g of the air gap formed between rotor 32 and armature 31 satisfy the relationship 0<L.sub.m +L.sub.g .ltoreq.2 mm.
    Type: Grant
    Filed: March 22, 1996
    Date of Patent: December 1, 1998
    Assignee: Seiko Epson Corporation
    Inventors: Akihito Uetake, Yoshihiko Yamagishi
  • Patent number: 5508576
    Abstract: A rotor having permanent magnets for a brushless electromotor includes a yoke formed from a plurality of silicon steel sheets laminated together and provided along its outer periphery with even number of, at least four magnetic poles. The magnetic poles are alternately provided substantially at equal distances from a rotational axis with slots to receive the respective permanent magnets such that the sides of the permanent magnets facing a rotary shaft have the same polarity. As a result, a compact and efficient rotor is obtained, and damage to or flying off of the permanent magnets is prevented.
    Type: Grant
    Filed: November 17, 1994
    Date of Patent: April 16, 1996
    Assignee: Seiko Epson Corporation
    Inventors: Takashi Nagate, Kenichi Endo, Yoshikazu Koike, Takeshi Seto, Yoshihiko Yamagishi
  • Patent number: 5371426
    Abstract: A rotor (31) of a brushless motor includes a rotary shaft (32), a main yoke (33) fitted over the rotary shaft, two magnetic pole heads (34a, 34b) radially projecting from the main yoke, two permanent magnets (36a, 36b) provided on the yoke between the magnetic pole heads such that the magnetic poles of identical polarity face each other across the rotary shaft, two auxiliary yokes (38a, 38b) mounted on the permanent magnets, and a cylindrical sleeve (40) made of a non-magnetic material provided on the outer circumferential surface of the magnetic pole heads and the auxiliary yokes.
    Type: Grant
    Filed: May 19, 1993
    Date of Patent: December 6, 1994
    Assignee: Seiko Epson Corporation
    Inventors: Takashi Nagate, Kenichi Endo, Yoshikazu Koike, Takeshi Seto, Yoshihiko Yamagishi
  • Patent number: 5369325
    Abstract: A rotor having permanent magnets for a brushless electromotor includes a yoke formed from a plurality of silicon steel sheets laminated together and provided along its outer periphery with even number of, at least four magnetic poles. The magnetic poles are alternately provided substantially at equal distances from a rotational axis with slots to receive the respective permanent magnets such that the sides of the permanent magnets facing a rotary shaft have the same polarity. As a result, a compact and efficient rotor is obtained, and damage to or flying off of the permanent magnets is prevented.
    Type: Grant
    Filed: February 4, 1993
    Date of Patent: November 29, 1994
    Assignee: Seiko Epson Corporation
    Inventors: Takashi Nagate, Kenichi Endo, Yoshikazu Koike, Takeshi Seto, Yoshihiko Yamagishi
  • Patent number: 5359248
    Abstract: A permanent magnet rotor (1) used in a corrosive atmosphere or liquid and provided with field permanent magnets (10) inserted into slots (9) of a lamination of silicon steel plates (2), wherein the outer surfaces of the field permanent magnets (10) are covered with anticorrosive plates made of an antiicorrosive material. The field permanent magnets (10) of the permanent rotor (1) can be used without being corroded, and the rotor (1) can be easily manufactured.
    Type: Grant
    Filed: April 8, 1993
    Date of Patent: October 25, 1994
    Assignee: Seiko Epson Corporation
    Inventors: Takashi Nagate, Kenichi Endo, Yoshikazu Koike, Takeshi Seto, Yoshihiko Yamagishi
  • Patent number: RE36367
    Abstract: A rotor having permanent magnets for a brushless electromotor includes a yoke formed from a plurality of silicon steel sheets laminated together and provided along its outer periphery with even number of, at least four magnetic poles. The magnetic poles are alternately provided substantially at equal distances from a rotational axis with slots to receive the respective permanent magnets such that the sides of the permanent magnets facing a rotary shaft have the same polarity. As a result, a compact and efficient rotor is obtained, and damage to or flying off of the permanent magnets is prevented.
    Type: Grant
    Filed: November 29, 1996
    Date of Patent: November 2, 1999
    Assignee: Seiko Epson Corporation
    Inventors: Takashi Nagate, Kenichi Endo, Yoshikazu Koike, Takeshi Seto, Yoshihiko Yamagishi