Patents by Inventor Fuyuki Maehara

Fuyuki Maehara 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).

  • Publication number: 20030095025
    Abstract: A voltage regulator controls an output of an automotive alternator by controlling an amount of excitation current supplied to a field winding of the alternator. The amount of the excitation current is sensed by a sensing resistor as a sensed voltage appearing across the sensing resistor. The sensed voltage is amplified by an amplifier to obtain a detected voltage, an amplifying factor of which is adjusted based on an reference voltage precisely corresponding to the amount of the excitation current, and thereby the detected voltage is equalized to the reference voltage. In this manner, the excitation current is precisely detected without mechanically adjusting a resistance of the sensing resistor by function-trimming or the like.
    Type: Application
    Filed: October 4, 2002
    Publication date: May 22, 2003
    Applicant: DENSO CORPORATION
    Inventor: Fuyuki Maehara
  • Publication number: 20020057545
    Abstract: A vehicular power generator control apparatus includes a switching transistor, a voltage control circuit, a high rotation speed detecting circuit, a leakage detecting circuit and a maximum conduction rate restricting circuit. The leakage detecting circuit detects leakage current flowing to a P-terminal. When the leakage current is detected, a maximum conduction rate set by the maximum conduction rate restricting circuit is changed from a small value at low rotation speeds to a large value. Thereby, field current flowing in a field coil is increased, a large voltage is generated at stator coils and current flows to a rectifying circuit to thereby reduce the leakage current which flows to the P-terminal.
    Type: Application
    Filed: September 28, 2001
    Publication date: May 16, 2002
    Inventors: Fuyuki Maehara, Keiji Takahashi, Toshinori Maruyama
  • Publication number: 20020027426
    Abstract: A voltage regulator of an automotive generator has a MOS transistor, flywheel diode, voltage detection circuit, and booster circuit. When a battery terminal voltage is below a voltage adjustment setting, current is supplied by a current supply circuit separate from a charge pump circuit to raise a gate voltage of the MOS transistor until the source voltage of the MOS transistor becomes greater than the reverse bias voltage of the flywheel diode, and the charge pump circuit output is applied to the MOS transistor after this specified value is reached. The charge pump circuit has an even number of capacitor stages.
    Type: Application
    Filed: August 29, 2001
    Publication date: March 7, 2002
    Applicant: DENSO CORPORATION
    Inventors: Hideto Okahara, Fuyuki Maehara, Toshinori Maruyama
  • Patent number: 6137247
    Abstract: A regulator for a vehicle-mounted alternator is connected to a vehicle-mounted engine control unit through a single signal line. The engine control unit produces serially a plurality of control signals in the form of pulse signals. The regulator includes an external signal receiver circuit, which detects periods of the control signals and duty ratios of the control signals. Control variables of the alternator such as a target voltage and gradual excitation period are determined by the detected periods. Control values of the control variables are determined by the detected duty ratios, respectively. The regulator thus controls a switching device, which supplies excitation current to the alternator based on the determined control variables and the control values.
    Type: Grant
    Filed: December 7, 1998
    Date of Patent: October 24, 2000
    Assignee: DENSO Corporation
    Inventors: Fuyuki Maehara, Hirohide Satoh
  • Patent number: 6043632
    Abstract: A permanent magnet made of ferrite magnet material used for a generator may be irreversibly demagnetized by a factor such as current supplied to a field coil, temperature of the permanent magnet and/or output current of an armature coil. When the field current exceeds a preset value, and also the output current exceeds a preset value, the field current is limited to prevent the irreversible demagnetization. Thus, the irreversible demagnetization of the permanent magnet can be prevented, while ensuring a sufficient amount of the output power. It is also effective that the field current or armature current is limited when the temperature of the permanent magnet is in a range of possible irreversible demagnetization.
    Type: Grant
    Filed: June 5, 1997
    Date of Patent: March 28, 2000
    Assignee: Denso Corporation
    Inventors: Fuyuki Maehara, Yasuhiro Takase, Wakako Kanazawa, Tadatoshi Asada, Hiroaki Ishikawa, Toshinori Maruyama
  • Patent number: 5966001
    Abstract: Battery voltage is compared by a comparator so that when the voltage of a normally-charged battery becomes higher than a normal reference voltage, it is regulated to be as high as a normal reference voltage. When an average value of the battery voltages in a period encompassing a typical operating speed of the engine becomes higher than an upper level, the reference voltage is lowered. On the other hand, when the average of the battery voltages in such period becomes lower than a lower level, the reference voltage is increased.
    Type: Grant
    Filed: April 22, 1997
    Date of Patent: October 12, 1999
    Assignee: Denso Corporation
    Inventors: Fuyuki Maehara, Hirohide Sato
  • Patent number: 5767636
    Abstract: To provide a vehicle power generating apparatus capable of transmitting plural kinds of control signals from an external control device to a generated voltage control unit provided in a generator for power generation control while curbing increases in the size of apparatus or wiring required and without degrading the noise reduction characteristics, a generated voltage control device is normally disposed integrally with a generator for maintaining the generated voltage at a predetermined target level. For transmission of a vehicle condition signal from an external control device to the generated voltage control device, the vehicle condition signal is converted into a binary pulse train signal before being transmitted. The generated voltage control device holds the binary pulse train signal received or a vehicle condition signal decoded from the binary pulse signal until the next reception. Thereby, complicated power generation control can be achieved with a small amount of communications.
    Type: Grant
    Filed: January 30, 1996
    Date of Patent: June 16, 1998
    Assignee: Nippondenso Co., Ltd.
    Inventors: Wakako Kanazawa, Fuyuki Maehara, Yasuhiro Takase
  • Patent number: 5754030
    Abstract: Duty ratio of a power switching transistor connected to the field coil is controlled according to whether or not a high-power load is connected. When the high power load is not connected, the duty ratio is made 60%, for example, so that excessive power not generated. On the other hand, when the high power load is connected, the duty ratio is increased to 100% so that full power is generated by the generator. The power switching transistor is also controlled according to the battery voltage in a well known manner.
    Type: Grant
    Filed: July 16, 1996
    Date of Patent: May 19, 1998
    Assignee: Nippondenso Co., Ltd.
    Inventors: Fuyuki Maehara, Tadatoshi Asada, Yasuhiro Takase, Wakako Kanazawa
  • Patent number: 5754031
    Abstract: The rotor of a generator is provided with permanent magnets to ensure start-up of electricity generation without externally supplied field current after a vehicle engine starts. When the generation is detected, the external field current is supplied from a battery so that the battery is charged by the generator, thereby to prevent battery discharge in a low speed range.
    Type: Grant
    Filed: August 1, 1996
    Date of Patent: May 19, 1998
    Assignee: Nippondenso Co., Ltd.
    Inventors: Wakako Kanazawa, Fuyuki Maehara, Yasuhiro Takase
  • Patent number: 5637986
    Abstract: The present invention relates to a device which supplies a field current to the field coil of an alternator for a vehicle in a gradually changing manner. In the device, a pulse voltage which has a pulse width corresponding to a phase difference between output signals of first and a second counters (15 and 16) is generated by a maximum duty ratio limiting circuit (19). When the alternator output voltage becomes higher than a reference voltage, the full-scale count time of the second counter is shortened relative to the full-scale count time of the first counter. On the other hand, when the output voltage becomes lower than the reference voltage, the same is elongated to thereby increase the phase difference. A switching transistor (12) is provided to control the field current supplied to the alternator field coil in response to the above pulse voltage.
    Type: Grant
    Filed: August 4, 1995
    Date of Patent: June 10, 1997
    Assignee: Nippondenso Co., Ltd.
    Inventors: Wakako Kanazawa, Fuyuki Maehara, Toshinori Maruyama
  • Patent number: 5319299
    Abstract: A charging control apparatus for a vehicle, which controls a power generation of an AC generator for charging a battery, comprises: a switching circuit connected in series to a field winding of the generator; a comparator for detecting a voltage of a battery and comparing the battery voltage with a sawtooth wave of a predetermined period; a memory device for storing a value regarding a duty factor of an output of the comparator at the same period as the predetermined period of the sawtooth; a control value increasing/decreasing circuit for increasing or decreasing a control value as an output, thereby making the stored value coincide with the control value; and an AND circuit to calculate AND of the control value and an output of the comparator.
    Type: Grant
    Filed: May 26, 1992
    Date of Patent: June 7, 1994
    Assignee: Nippondenso Co., Ltd.
    Inventor: Fuyuki Maehara
  • Patent number: 4957876
    Abstract: This invention provides a resin sealed IC regulator, which comprises a first connecting terminal electrically connected to a generator, a second connecting terminal electrically connected to a device other than the generator, a monolithic IC which controls an operation of the generator, mounted on a conductive member, and connected to both the first connecting terminal and the second connecting terminal and a resin molded portion of an electric insulating resin sealing the monolithic IC and at least a portion of the first and second connecting terminals are connected to the monolithic IC.Whereby an IC regulator which can be effectively used with an electrical load can be obtained, and further, an IC regulator having a more reliable control performance and able to be produced at low production cost can be obtained.
    Type: Grant
    Filed: January 17, 1990
    Date of Patent: September 18, 1990
    Assignee: Nippondenso Co., Ltd.
    Inventors: Hiroshi Shibata, Fuyuki Maehara, Akira Shintai, Hidetoshi Kato
  • Patent number: 4899209
    Abstract: This invention provides a resin sealed IC regulator, which comprises a first connecting terminal electrically connected to a generator, a second connecting terminal electrically connected to a device other than the generator, a monolithic IC which controls an operation of the generator, mounted on a conductive member, and connected to both the first connecting terminal and the second connecting terminal and a resin molded portion of an electric insulating resin sealing the monolithic IC and at least a portion of the first and second connecting terminals are connected to the monlithic IC.Whereby an IC regulator which can be effectively used with an electrical load can be obtained, and further, an IC regulator having a more reliable control performance and able to be produced at low production cost can be obtained.
    Type: Grant
    Filed: June 3, 1988
    Date of Patent: February 6, 1990
    Assignee: Nippondenso Co., Ltd.
    Inventors: Hiroshi Shibata, Fuyuki Maehara, Akira Shintai, Hidetoshi Kato