Patents by Inventor Takeshi Ohi

Takeshi Ohi 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: 7866627
    Abstract: A normally-closed electromagnetic valve has a body member having a receiving space, a fixed core, a valve seat, a moving core, a resilient member urging the moving core toward the valve seat, a valve element and a coil exciting the fixed core to produce an attracting force between the fixed core and the moving core, wherein the moving core has a through hole, the valve element is inserted into the through hole from the valve seat-side, at least a part of the resilient member is inserted into the through hole from the fixed core-side and the resilient member is compressed between a moving core-side end of the fixed core and a fixed core-side end of the valve seat.
    Type: Grant
    Filed: June 14, 2007
    Date of Patent: January 11, 2011
    Assignee: Nissin Kogyo Co., Ltd.
    Inventors: Takeshi Ohi, Takaaki Komaba, Hiroaki Tokoi
  • Patent number: 7554173
    Abstract: A semiconductor device accurately monitoring temperature of a semiconductor chip even in a noisy environment, while not requiring a highly accurate detection circuit. A PTC element is bonded onto an IGBT chip. Then, a constant current flows from a constant current source through the PTC element, and an output voltage of the PTC element is detected by a voltage monitor. When output voltage increases, a voltage applied to a gate electrode by a detection circuit is decreased. Since the PTC element is directly arranged on the IGBT chip, the temperature of the IGBT chip can be monitored with high accuracy. Further, since the change in output voltage of the PTC element per 1° C. is large, a highly accurate detection circuit is not necessary, thereby allowing accurate monitoring of the temperature of the IGBT chip even in a noisy environment.
    Type: Grant
    Filed: December 19, 2005
    Date of Patent: June 30, 2009
    Assignee: Mitsubishi Electric Corporation
    Inventors: Takashi Inaguchi, Takeshi Ohi, Katsuhiko Fukuhara, Naoshi Yamada, Yoshitsugu Inaba, Takao Mitsuhashi
  • Publication number: 20080006897
    Abstract: A semiconductor device accurately monitoring temperature of a semiconductor chip even in a noisy environment, while not requiring a highly accurate detection circuit. A PTC element is bonded onto an IGBT chip. Then, a constant current flows from a constant current source through the PTC element, and an output voltage of the PTC element is detected by a voltage monitor. When output voltage increases, a voltage applied to a gate electrode by a detection circuit is decreased. Since the PTC element is directly arranged on the IGBT chip, the temperature of the IGBT chip can be monitored with high accuracy. Further, since the change in output voltage of the PTC element per 1° C. is large, a highly accurate detection circuit is not necessary, thereby allowing accurate monitoring of the temperature of the IGBT chip even in a noisy environment.
    Type: Application
    Filed: December 19, 2005
    Publication date: January 10, 2008
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Takashi Inaguchi, Takeshi Ohi, Katsuhiko Fukuhara, Naoshi Yamada, Yoshitsugu Inaba, Takao Mitsuhashi
  • Publication number: 20070257222
    Abstract: A normally-closed electromagnetic valve has a body member having a receiving space, a fixed core, a valve seat, a moving core, a resilient member urging the moving core toward the valve seat, a valve element and a coil exciting the fixed core to produce an attracting force between the fixed core and the moving core, wherein the moving core has a through hole, the valve element is inserted into the through hole from the valve seat-side, at least a part of the resilient member is inserted into the through hole from the fixed core-side and the resilient member is compressed between a moving core-side end of the fixed core and a fixed core-side end of the valve seat.
    Type: Application
    Filed: June 14, 2007
    Publication date: November 8, 2007
    Applicant: NISSIN KOGYO CO., LTD.
    Inventors: Takeshi OHI, Takaaki KOMABA, Hiroaki TOKOI
  • Patent number: 7246632
    Abstract: A normally-closed electromagnetic valve has a body member having a receiving space, a fixed core, a valve seat, a moving core, a resilient member urging the moving core toward the valve seat, a valve element and a coil exciting the fixed core to produce an attracting force between the fixed core and the moving core, wherein the moving core has a through hole, the valve element is inserted into the through hole from the valve seat-side, at least a part of the resilient member is inserted into the through hole from the fixed core-side and the resilient member is compressed between a moving core-side end of the fixed core and a fixed core-side end of the valve seat.
    Type: Grant
    Filed: March 29, 2005
    Date of Patent: July 24, 2007
    Assignee: Nissin Kogyo Co., Ltd.
    Inventors: Takeshi Ohi, Takaaki Komaba, Hiroaki Tokoi
  • Patent number: 7240893
    Abstract: A normally closed solenoid valve includes a fixed core, a valve portion including a valve seat and a valve body, a movable core disposed between the fixed core and the valve seat, a resilient biasing member for biasing the movable core in a valve-closing direction and a coil. When energized, the coil generates an attracting force between the movable core and the fixed core against a biasing force by the resilient biasing member to cause the movable core to retreat from an initial position where the valve seat is in a closed state. When a characteristic graph line of spacing distance/attracting force that defines the attracting force in relation with a spacing distance between the fixed core and the movable core provides an inclination A (N/mm) at the initial position, the compression resiliency coefficient of the resilient biasing member is set to A (N/mm).
    Type: Grant
    Filed: July 9, 2004
    Date of Patent: July 10, 2007
    Assignee: Nissan Kogyo Co., Ltd.
    Inventors: Takaaki Komaba, Takeshi Ohi
  • Patent number: 6967519
    Abstract: A drive circuit for a power semiconductor device includes: a sampling signal generating circuit for detecting that an input control signal instructs OFF and outputting a sampling signal at the time instant of start of a Miller period of time of an IGBT; a gate voltage detecting circuit for detecting a Miller voltage of the IGBT at the timing when the sampling signal is inputted and outputting, when the Miller voltage is equal to or larger than a threshold, an over-current detection signal; and a gate voltage controlling circuit for controlling, in response to the over-current detection signal, a gate voltage of the IGBT in such a way that the IGBT is turned OFF at slower speed than in the normal state. Thus, it is possible to suppress a surge voltage which is generated when the IGBT is turned OFF during the flow of an over-current.
    Type: Grant
    Filed: January 16, 2003
    Date of Patent: November 22, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasushi Nakayama, Takeshi Ohi, Ryuichi Hashido
  • Publication number: 20050218364
    Abstract: A normally-closed electromagnetic valve has a body member having a receiving space, a fixed core, a valve seat, a moving core, a resilient member urging the moving core toward the valve seat, a valve element and a coil exciting the fixed core to produce an attracting force between the fixed core and the moving core, wherein the moving core has a through hole, the valve element is inserted into the through hole from the valve seat-side, at least a part of the resilient member is inserted into the through hole from the fixed core-side and the resilient member is compressed between a moving core-side end of the fixed core and a fixed core-side end of the valve seat.
    Type: Application
    Filed: March 29, 2005
    Publication date: October 6, 2005
    Applicant: Nissin Kogyo Co. Ltd
    Inventors: Takeshi Ohi, Takaaki Komaba, Hiroaki Tokoi
  • Patent number: 6906574
    Abstract: A drive circuit includes a gate voltage detector that detects a gate-emitter voltage Vge that appears between the gate and emitter of a power semiconductor device throughout a detection time period during which a sampler allows the process of detecting the gate-emitter voltage Vge, and that recognizes the occurrence of an abnormality in the power semiconductor device when the gate-emitter voltage Vge exceeds a reference value. Therefore, the drive circuit can protect the power semiconductor device with higher reliability by promptly detecting the occurrence of a short circuit even when the power semiconductor device is resistant to high voltages.
    Type: Grant
    Filed: July 28, 2003
    Date of Patent: June 14, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Ohi, Yasushi Nakayama, Takeshi Tanaka
  • Publication number: 20050029478
    Abstract: A normally closed solenoid valve includes a fixed core, a valve portion including a valve seat and a valve body, a movable core disposed between the fixed core and the valve seat, a resilient biasing member for biasing the movable core in a valve-closing direction and a coil. When energized, the coil generates an attracting force between the movable core and the fixed core against a biasing force by the resilient biasing member to cause the movable core to retreat from an initial position where the valve seat is in a closed state. When a characteristic graph line of spacing distance/attracting force that defines the attracting force in relation with a spacing distance between the fixed core and the movable core provides an inclination A (N/mm) at the initial position, the compression resiliency coefficient of the resilient biasing member is set to A(N/mm).
    Type: Application
    Filed: July 9, 2004
    Publication date: February 10, 2005
    Inventors: Takaaki Komaba, Takeshi Ohi
  • Publication number: 20050001189
    Abstract: A normally open solenoid valve, includes: a coil; a fixed core that is excited when the coil is energized, the fixed core having a through hole and an opening formed at an end of the throughhole; a valve seat disposed at the opening; a valve element inserted through the through hole, the valve element including a valve part for coming into contact with the valve seat and a roughly columnar shaft part extending from the valve part; and a movable core that pushes and moves the valve element. The shaft part has a plurality of sliding portions that are slidable on the inner surface of the through hole and are formed to be spaced in an axial direction of the shaft part and a narrowed portion having an outer diameter smaller than the sliding portions between the plurality of sliding portions.
    Type: Application
    Filed: June 2, 2004
    Publication date: January 6, 2005
    Inventors: Yoshiyuki Takamatsu, Masaya Shigeta, Takeshi Ohi
  • Patent number: 6836006
    Abstract: In an IGBT module which contains an IGBT device and a diode device connected to each other and accommodated in a case and which radiates heat generated in operation through a radiation board, an object is to reduce the area of the module in the lateral direction to achieve size reduction. The collector electrode surface of an IGBT device is provided on a radiation board, and an element connecting conductor is bonded with conductive resin on the emitter electrode surface. The anode electrode surface of a diode device is bonded on it with the conductive resin. The IGBT device and the diode device are thus stacked and connected in the vertical direction.
    Type: Grant
    Filed: November 29, 1999
    Date of Patent: December 28, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hirotaka Muto, Takeshi Ohi, Takumi Kikuchi, Toshiyuki Kikunaga
  • Publication number: 20040027762
    Abstract: A drive circuit includes a gate voltage detector that detects a gate-emitter voltage Vge that appears between the gate and emitter of a power semiconductor device throughout a detection time period during which a sampler allows the process of detecting the gate-emitter voltage Vge, and that recognizes the occurrence of an abnormality in the power semiconductor device when the gate-emitter voltage Vge exceeds a reference value. Therefore, the drive circuit can protect the power semiconductor device with higher reliability by promptly detecting the occurrence of a short circuit even when the power semiconductor device is resistant to high voltages.
    Type: Application
    Filed: July 28, 2003
    Publication date: February 12, 2004
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeshi Ohi, Yasushi Nakayama, Takeshi Tanaka
  • Publication number: 20030180997
    Abstract: A drive circuit for a power semiconductor device includes: a sampling signal generating circuit for detecting that an input control signal instructs OFF and outputting a sampling signal at the time instant of start of a Miller period of time of an IGBT; a gate voltage detecting circuit for detecting a Miller voltage of the IGBE at the timing when the sampling signal is inputted and outputting, when the Miller voltage is equal to or larger than a threshold, an over-current detection signal; and a gate voltage controlling circuit for controlling, in response to the over-current detection signal, a gate voltage of the IGBT in such a way that the IGBT is turned OFF at slower speed than in the normal state. Thus, it is possible to suppress a surge voltage which is generated when the IGBT is turned OFF during the flow of an over-current.
    Type: Application
    Filed: January 16, 2003
    Publication date: September 25, 2003
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasushi Nakayama, Takeshi Ohi, Ryuichi Hashido
  • Patent number: 6580147
    Abstract: P-electrode 30a and N-electrode 31a of a semiconductor device 2, and capacitors 10 in a plate-like shape or a block-like shape respectively connected to U-phase 40, V-phase 41, and W-phase 42 having a switching element 20 and a diode 21 are built in a semiconductor device 2, and a single or a plurality of capacitors 10 are respectively connected to P-electrodes 30a and N-electrodes 31a in each of the phases, whereby the smoothing capacitors are built in the semiconductor device to reduce wiring inductances, the capacitors are miniaturized, and an entire electric power converting device, i.e. inverter, is miniaturized.
    Type: Grant
    Filed: March 14, 2001
    Date of Patent: June 17, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toru Kimura, Dai Nakajima, Tatsuya Okuda, Takeshi Ohi, Takanobu Yoshida, Naoki Yoshimatsu, Yuuji Kuramoto, Toshinori Yamane, Masakazu Fukada, Majumdar Gourab
  • Publication number: 20020043708
    Abstract: In an IGBT module which contains an IGBT device and a diode device connected to each other and accommodated in a case and which radiates heat generated in operation through a radiation board, an object is to reduce the area of the module in the lateral direction to achieve size reduction. The collector electrode (32) surface of an IGBT device (28) is provided on a radiation board (26), and an element connecting conductor (35) is bonded with conductive resin (36) on the emitter electrode (30) surface. The anode electrode (33) surface of a diode device (29) is bonded on it with the conductive resin (36). The IGBT device (28) and the diode device (29) are thus stacked and connected in the vertical direction.
    Type: Application
    Filed: November 29, 1999
    Publication date: April 18, 2002
    Inventors: HIROTAKA MUTO, TAKESHI OHI, TAKUMI KIKUCHI, TOSHIYUKI KIKUNAGA
  • Publication number: 20010035562
    Abstract: P-electrode 30a and N-electrode 31a of a semiconductor device 2, and capacitors 10 in a plate-like shape or a block-like shape respectively connected to U-phase 40, V-phase 41, and W-phase 42 having a switching element 20 and a diode 21 are built in a semiconductor device 2, and a single or a plurality of capacitors 10 are respectively connected to P-electrodes 30a and N-electrodes 31a in each of the phases, whereby the smoothing capacitors are built in the semiconductor device to reduce wiring inductances, the capacitors are miniaturized, and an entire electric power converting device, i.e. inverter, is miniaturized.
    Type: Application
    Filed: March 14, 2001
    Publication date: November 1, 2001
    Inventors: Toru Kimura, Dai Nakajima, Tatsuya Okuda, Takeshi Ohi, Takanobu Yoshida, Naoki Yoshimatsu, Yuuji Kuramoto, Toshinori Yamane, Masakazu Fukada, Majumdar Gourab
  • Patent number: 6236110
    Abstract: A current detecting sensor includes parallel flat plates opposed in a substantially U-shape in cross-section. Since the flat plates are opposed to each other, the current detecting sensor has reduced inductance, significantly decreasing frequency dependency of outputs from detection terminals.
    Type: Grant
    Filed: March 29, 2000
    Date of Patent: May 22, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hirotaka Muto, Toshiyuki Kikunaga, Takeshi Ohi, Shin-ichi Kinouchi, Takeshi Horiguchi, Osamu Usui, Tatsuya Okuda
  • Patent number: 6215185
    Abstract: An object is to obtain long-term reliability of an electric connection in a power semiconductor module. In a power semiconductor module, the main circuit interconnection directly connected to a power semiconductor chip (3) is formed of a busbar (6) and the power semiconductor chip (3) and the busbar electrode (6a) of the busbar (6) are electrically connected through a conductive resin (12). A member (13) having lower thermal expansion than the busbar electrode (6a) is joined to the busbar electrode (6a) in the part adjacent to said power semiconductor chip (3).
    Type: Grant
    Filed: December 8, 1999
    Date of Patent: April 10, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takumi Kikuchi, Hirofumi Fujioka, Toshiyuki Kikunaga, Hirotaka Muto, Shinichi Kinouchi, Osamu Usui, Takeshi Ohi