Patents by Inventor Takayuki Yamawaki

Takayuki Yamawaki 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: 6876109
    Abstract: A claw-pole type stepping motor comprises: a rotor which is shaped substantially cylindrical, and which has a rotary shaft at its radial center; and two stators which are shaped like a cup, each have at least one magnetic coil, are coupled to each other so as to rotatably house the rotor with their magnetic coils located respectively toward both axial end faces of the rotor, and which each have two pole tooth arrays magnetically connected to each other such that magnetic phase difference therebetween at tips of respective pole teeth is 180 degrees in terms of electrical angle, and in the motor thus structure, three pipes of aluminum go axially through the two stators so as to hold together the two stators.
    Type: Grant
    Filed: July 2, 2004
    Date of Patent: April 5, 2005
    Assignee: Minebea Co., Ltd.
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Toshihiko Nagata, Naoyuki Harada
  • Publication number: 20050046305
    Abstract: A claw-pole type stepping motor comprises: a rotor assembly shaped substantially cylindrical, and having a center shaft; and a stator assembly composed of two cup-shaped stator units which are coupled to each other coaxially so as to axially sandwich the rotor assembly, and which each include a bobbin having a magnet wire wound therearound, and two pole tooth arrays magnetically connected to each other and shifted in phase from each other by an electrical angle of 180 degrees. In the motor, each stator unit further includes a cover ring which protects the magnet wire wound around the bobbin against resin injected when the stator unit is resin-molded for an integrated solid structure. The motor structured as described above can be successfully resin-molded so as to enable elimination of a motor case, thus achieving downsizing for the dimension of the eliminated motor case while maintaining a sufficient mechanical strength.
    Type: Application
    Filed: August 30, 2004
    Publication date: March 3, 2005
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Toshihiko Nagata
  • Publication number: 20050006960
    Abstract: A claw-pole type stepping motor comprises: a rotor which is shaped substantially cylindrical, and which has a rotary shaft at its radial center; and two stators which are shaped like a cup, each have at least one magnetic coil, are coupled to each other so as to rotatably house the rotor with their magnetic coils located respectively toward both axial end faces of the rotor, and which each have two pole tooth arrays magnetically connected to each other such that magnetic phase difference therebetween at tips of respective pole teeth is 180 degrees in terms of electrical angle, and in the motor thus structure, three pipes of aluminum go axially through the two stators so as to hold together the two stators.
    Type: Application
    Filed: July 2, 2004
    Publication date: January 13, 2005
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Toshihiko Nagata, Naoyuki Harada
  • Patent number: 6727608
    Abstract: A claw-pole type stepping motor which includes a stator in which coils are arranged in association with a pair of inner and outer yokes and a pair of pole tooth sections thereby forming a magnetic circuit; and a rotor magnet which is rotatably disposed opposite to the pair of pole tooth sections, each of the pair of pole tooth sections being prepared discretely from each of the inner and outer yokes by punching out a soft magnetic steel plate so as to form a piece having a belt portion and a plurality of pole teeth integrally connected to the belt portion and thereafter rolling into a cylindrical shape. Thus, it becomes possible to set arbitrarily individual dimensions of each of the pole teeth as required by the characteristics of a motor, thereby providing an excellent high output and miniature motor.
    Type: Grant
    Filed: May 28, 2002
    Date of Patent: April 27, 2004
    Assignee: Minebea Co, Ltd.
    Inventors: Takayuki Yamawaki, Hiroshi Sano, Toshihiko Nagata
  • Patent number: 6710503
    Abstract: A stator structure of a claw-pole type stepping motor which has an outer stator yoke having a plurality of pole teeth; an inner stator yoke having a plurality of pole teeth which are intermeshed with the plurality of pole teeth of the outer stator yoke with a gap therebetween; a coil disposed around the circumferential periphery defined by the pole teeth; and a covering which covers the coil. The stator external walls are only partially formed so as to allow the covering to be exposed in regions where the stator external walls are not formed. The stator structure of the present invention enables a dimensional reduction in size of a motor by a dimension corresponding to double the thickness of the stator yoke material, without impairing the performance of the motor.
    Type: Grant
    Filed: June 5, 2002
    Date of Patent: March 23, 2004
    Assignee: Minebea Co., Ltd.
    Inventors: Takayuki Yamawaki, Hiroshi Sano, Toshihiko Nagata
  • Publication number: 20020190584
    Abstract: A stator structure of a claw-pole type stepping motor of the present invention comprises: an outer stator yoke having a plurality of pole teeth; an inner stator yoke having a plurality of pole teeth which are intermeshed with the plurality of pole teeth of the outer stator yoke with a gap therebetween; a coil disposed around the circumferential periphery defined by the pole teeth; and a covering which covers the coil, with stator external walls being partially formed so as to allow the covering to be exposed in regions where the stator external walls are not formed. The stator structure of the present invention enables a dimensional reduction in size of a motor by a dimension corresponding to double the thickness of the stator yoke material, without impairing the performance of the motor.
    Type: Application
    Filed: June 5, 2002
    Publication date: December 19, 2002
    Applicant: Minebea Co., Ltd.
    Inventors: Takayuki Yamawaki, Hiroshi Sano, Toshihiko Nagata
  • Patent number: 6396189
    Abstract: A stator assembly of a rotary electric device is manufactured and assembled at reduced cost with an enhanced level of precision. A stator assembly of a rotary electric device comprising a yoke provided with a plurality of stationary magnetic poles and a yoke plate bonded to said yoke by means of synthetic resin in a mold to form an integral unit for enclosing a stator coil is assembled by bringing an alignment pin arranged on a jig for combining the yoke and the yoke plate into engagement with a corresponding alignment sections of the yoke and the yoke plate to put the yoke and the yoke plate together in order to produce a unitary stator assembly and a step of placing the unitary stator assembly of the yoke and the yoke plate in an injection metal mold with said alignment section fitted to an alignment pin arranged in the mold for mutual engagement and injecting synthetic resin into the mold to bond the yoke and the yoke plate together.
    Type: Grant
    Filed: September 21, 1995
    Date of Patent: May 28, 2002
    Assignee: Minebea Co., Ltd.
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Hiroshi Sano, Kazuo Muramatsu
  • Patent number: 6177751
    Abstract: The object of the present invention is to provide a rotary electric machine that provides bobbins with good assembling efficiency and allows no dislocation of the stator. A motor 2 comprises a case 4, a stator 6 secured inside the case 4, a rotor 10 formed into one piece with a rotating shaft 8. The stator 6 comprises stator yokes 32 and the stator yokes are secured in a radial manner in the case 4. Furthermore, resin 58 is filled in between the stator 6 and the case 4 with a space for the rotor being left. The stator yokes 32 comprise a salient pole 34, a bobbin 36 for holding the salient pole 34, and a magnetic wire 38 wound around the bobbin 36. A collar 39b of the bobbin 36 is formed so as to contact each other with notches 3 formed on two, upper and lower edge portions. Accordingly, combining two bobbins 36, 36 allows through-holes 5 penetrating the collar 39b thereof.
    Type: Grant
    Filed: August 20, 1999
    Date of Patent: January 23, 2001
    Assignee: Minebea Co., Ltd.
    Inventors: Yuzuru Suzuki, Sakae Fujitani, Kunitake Matsushita, Takayuki Yamawaki, Hiroshi Sano, Kazuo Muramatsu, Taichi Nishio
  • Patent number: 6166468
    Abstract: The object of the present invention is to provide a rotary electric machine which has high assembly accuracy, high heat dissipating efficiency, and excellent durability at the bearing portion. A motor comprises a case, a stator secured within the case, and a rotor formed into one piece with a rotary shaft. The case is provided, on both end faces, with flanges, and one of the flanges is provided with a ball bearing. A stator is radially secured within the case, resin is filled in between the stator and the case with a space of the rotor being left, and a bearing housing and a boss are formed on one side. An open portion is formed in between ribs of the bearing housing, and inserting the bearing into the bearing housing causes a part of the bearing to be exposed through the open portion to fixedly contact with the flange. This allows supporting the bearing securely, and allows frictional heat generated, and the like, to dissipate to the outside via the flange.
    Type: Grant
    Filed: August 3, 1999
    Date of Patent: December 26, 2000
    Assignee: Minebea Co., Ltd.
    Inventors: Yuzuru Suzuki, Sakae Fujitani, Kunitake Matsushita, Takayuki Yamawaki, Hiroshi Sano, Kazuo Muramatsu, Taichi Nishio
  • Patent number: 5856718
    Abstract: A cup shaped base 12 and a cap 13 are coupled, therein coil spring 14 is accommodated to form a holder 11, and the holder is interposed between the bearing 3 of a rotor shaft 4 and a sleeve 5. Different from being directly mounted on the rotor shaft, since the base 12 is provisionally held on the rotor shaft, the operation efficiency at the time of assembling the motor is outstandingly increased.
    Type: Grant
    Filed: October 8, 1997
    Date of Patent: January 5, 1999
    Assignee: Minebea Co., Ltd.
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Hiroshi Sano, Hiroaki Ezure
  • Patent number: 5829119
    Abstract: A stator assembly of a rotary electric device is manufactured and assembled at reduced cost with an enhanced level of precision. A stator assembly of a rotary electric device comprising a yoke provided with a plurality of stationary magnetic poles and a yoke plate bonded to said yoke by means of synthetic resin in a mold to form an integral unit for enclosing a stator coil is assembled by bringing an alignment pin arranged on a jig for combining the yoke and the yoke plate into engagement with a corresponding alignment sections of the yoke and the yoke plate to put the yoke and the yoke plate together in order to produce a unitary stator assembly and a step of placing the unitary stator assembly of the yoke and the yoke plate in an injection metal mold with said alignment section fitted to an alignment pin arranged in the mold for mutual engagement and injecting synthetic resin into the mold to bond the yoke and the yoke plate together.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: November 3, 1998
    Assignee: Minebea Co., Ltd
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Hiroshi Sano, Kazuo Muramatsu
  • Patent number: 5777413
    Abstract: A bearing installation for a Floppy Disk Driver motor which is simple in structure and high in accuracy of a rotating action of a rotary shaft, thus hardly impairing the read and write characteristics of a Floppy Disk Driver device.
    Type: Grant
    Filed: December 28, 1995
    Date of Patent: July 7, 1998
    Assignee: Minebea Co., Ltd.
    Inventors: Toshihiko Nagata, Hiroshi Sano, Takayuki Yamawaki, Kunitake Matsushita
  • Patent number: 5689145
    Abstract: An object of the present invention is to provide a novel stator structure in an electrical rotating machine which has a stator to one end of which an end plate provided with a bearing is fixedly mounted and a rotor rotatably supported by the bearing, in which unwanted metal particles produced during welding of the end plate to the stator are prevented from entering between the stator and the rotor.Positioning protrusions 61 are formed extending axially from the one end of the stator and positioning apertures 71 are provided in the end plate 65 for corresponding to and engaging with the positioning protrusions 61. Also, welding projections to be melted by resistance welding are arranged as located substantially on straight lines respectively extending from the rotation shaft 67 across the positioning protrusions 61 and on the outer side of the positioning protrusions 61. The end plate 65 is joined to the one end of the stator by welding at welding points 14.
    Type: Grant
    Filed: July 3, 1995
    Date of Patent: November 18, 1997
    Assignee: Minebea Co., Ltd.
    Inventors: Kunitake Matsushita, Takayuki Yamawaki, Hideki Matsuura, Hiroshi Sano
  • Patent number: 5486054
    Abstract: A bearing system in a motor for a floppy disk drive (FDD) apparatus includes a protective cap mounted to one side of the motor, a first pivot bearing arranged movable to and from the protective cap in an axial direction of a rotary shaft, a thrust spring provided for urging the first pivot bearing in the axial direction of the rotary shaft, the rotary shaft having a rotor fixedly mounted thereto and rotatably supported at one end by the first pivot bearing and at the other end by a second pivot bearing mounted to a base for installation of the motor, and an alignment bushing arranged through which the rotary shaft of the motor extends without direct contact and closely fitted into a positioning hole provided in a plate to which the motor is secured. The rotary shaft remains not in direct contact with (spaced apart from) the alignment bushing and, acting as a leadscrew, can thus rotate at a higher accuracy, eliminating intrinsic drawbacks of the FDD motor.
    Type: Grant
    Filed: September 12, 1994
    Date of Patent: January 23, 1996
    Assignee: Minebea Co., Ltd.
    Inventors: Toshihiko Nagata, Hiroshi Sano, Takayuki Yamawaki, Kunitake Matsushita
  • Patent number: 4841190
    Abstract: A permanent-magnet stepping motor includes a stator which has resinous protrusions at its one end. An end plate disposed on one side of the stator is molded integrally with the stator. A flange plate is fixed to the other side of the stator, using the protrusions. The stator includes four stator yokes and two annular coils that are disposed at given positions. These yokes and coils are coupled together by molding a resin.
    Type: Grant
    Filed: April 27, 1988
    Date of Patent: June 20, 1989
    Assignee: Minebea Co., Ltd.
    Inventors: Kunitake Matsushita, Hiroshi Sakuma, Takayuki Yamawaki, Takashi Yoshikura, Hiroshi Sano, Yuzuru Suzuki, Michihiro Torii, Tohru Ohnuki