Patents by Inventor Masaki Ohfuji

Masaki Ohfuji 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: 10352327
    Abstract: A vacuum pump includes: a rotor that is rotated to perform evacuation; a pump disassembly detection circuit that detects a disassembled state in which the vacuum pump is disassembled; and a pump operation prohibition circuit that prohibits rotary drive of the rotor when the pump operation prohibition circuit determines that the pump disassembly detection circuit has detected the disassembled state.
    Type: Grant
    Filed: December 19, 2011
    Date of Patent: July 16, 2019
    Assignee: SHIMADZU CORPORATION
    Inventors: Masaki Ohfuji, Toshifumi Hashimoto, Shingo Tanaka
  • Patent number: 9353755
    Abstract: A turbomolecular pump device includes: a turbomolecular pump main body; a power unit that drives the turbomolecular pump main body; and a water cooling unit that is provided between the turbomolecular pump main body and the power unit, wherein components provided in a casing of the power unit are classified into an intensive cooling required component that requires intensive cooling, a moderate cooling required component that requires moderate cooling, and a no cooling required component that requires substantially no cooling, the intensive cooling required component is mounted on a first high-conductivity substrate contacting to the water cooling unit, the moderate cooling required component is mounted on a second high heat-conductive substrate contacting to an inner surface of the casing, and the no cooling required component is mounted on a substrate arranged in a space between the first high heat-conductive substrate and the second high heat-conductive substrate.
    Type: Grant
    Filed: March 11, 2010
    Date of Patent: May 31, 2016
    Assignee: SHIMADZU CORPORATION
    Inventors: Yoshihiro Nagano, Masaki Ohfuji, Junichiro Kozaki
  • Patent number: 8613604
    Abstract: The provision of the components requiring cooling on top of the cooling mechanism enables the cooling efficiency to be increased. Furthermore, a case of a control device is attached to the cooling mechanism whereon the components requiring cooling are disposed. The cooling mechanism fulfills the role of the contact surface of the case of the control device with the turbomolecular pump main unit, where the case does not have a case panel on the contact surface with the turbomolecular pump main unit. The cooling mechanism fulfills the role of one surface of the case for the control device, where the cooling mechanism is structured integrally with the control device. Additionally, the turbomolecular pump main unit, the cooling mechanism, and the control device are structured integrally by the turbomolecular pump main unit and the cooling mechanism being in contact.
    Type: Grant
    Filed: March 18, 2010
    Date of Patent: December 24, 2013
    Assignee: Shimadzu Corporation
    Inventors: Yoshihiro Nagano, Toshiki Yamaguchi, Takuto Onishi, Masaki Ohfuji, Junichiro Kozaki
  • Publication number: 20130224042
    Abstract: A vacuum pump includes: a rotor that is rotated to perform evacuation; a pump disassembly detection circuit that detects a disassembled state in which the vacuum pump is disassembled; and a pump operation prohibition circuit that prohibits rotary drive of the rotor when the pump operation prohibition circuit determines that the pump disassembly detection circuit has detected the disassembled state.
    Type: Application
    Filed: December 19, 2011
    Publication date: August 29, 2013
    Applicant: SHIMADZU CORPORATION
    Inventors: Masaki Ohfuji, Toshifumi Hashimoto, Shingo Tanaka
  • Publication number: 20120321442
    Abstract: A turbomolecular pump device includes: a turbomolecular pump main body; a power unit that drives the turbomolecular pump main body; and a water cooling unit that is provided between the turbomolecular pump main body and the power unit, wherein components provided in a casing of the power unit are classified into an intensive cooling required component that requires intensive cooling, a moderate cooling required component that requires moderate cooling, and a no cooling required component that requires substantially no cooling, the intensive cooling required component is mounted on a first high-conductivity substrate contacting to the water cooling unit, the moderate cooling required component is mounted on a second high heat-conductive substrate contacting to an inner surface of the casing, and the no cooling required component is mounted on a substrate arranged in a space between the first high heat-conductive substrate and the second high heat-conductive substrate.
    Type: Application
    Filed: March 11, 2010
    Publication date: December 20, 2012
    Applicant: SHIMADZU CORPORATION
    Inventors: Yoshihiro Nagano, Masaki Ohfuji, Junichiro Kozaki
  • Patent number: 7965054
    Abstract: A vacuum pump capable of accurately detecting a rotor temperature based on a change in permeability of a magnetic material. Two targets are fixed to a nut opposed to a gap sensor. The nut is made of pure iron, and a surface of the nut opposed to the gap sensor serves as a target. The target has a Curie temperature greater than a temperature monitoring range, and each of the targets has a Curie temperature falling within the temperature monitoring range. When the targets become opposed to the gap sensor in turn according to rotation of a rotor, three types of signals are output from the gap sensor. The difference-signal generation means generates a difference signal of each the targets, on the basis of a signal of the target. The difference signal is compared with a reference signal V0 for detecting the Curie temperatures to detect a rotor temperature.
    Type: Grant
    Filed: July 26, 2007
    Date of Patent: June 21, 2011
    Assignee: Shimadzu Corporation
    Inventors: Yoshio Tsunazawa, Akira Arakawa, Junichiro Kozaki, Masaki Ohfuji
  • Publication number: 20100247336
    Abstract: The provision of the components requiring cooling on top of the cooling mechanism enables the cooling efficiency to be increased. Furthermore, a case of a control device is attached to the cooling mechanism whereon the components requiring cooling are disposed. The cooling mechanism fulfills the role of the contact surface of the case of the control device with the turbomolecular pump main unit, where the case does not have a case panel on the contact surface with the turbomolecular pump main unit. The cooling mechanism fulfills the role of one surface of the case for the control device, where the cooling mechanism is structured integrally with the control device. Additionally, the turbomolecular pump main unit, the cooling mechanism, and the control device are structured integrally by the turbomolecular pump main unit and the cooling mechanism being in contact.
    Type: Application
    Filed: March 18, 2010
    Publication date: September 30, 2010
    Applicant: SHIMADZU CORPORATION
    Inventors: Yoshihiro Nagano, Toshiki Yamaguchi, Takuto Onishi, Masaki Ohfuji, Junichiro Kozaki
  • Patent number: 7679248
    Abstract: Disclosed is a magnetic bearing system capable of simplifying a demodulation operation and reducing a processing load associated with a magnetic levitation control. A carrier signal having a frequency fc is apply to a sensor through a filter. The sensor operates to modulate the carrier signal, and a difference amplifier operates to calculate a difference between the amplitude-modulated signal FAM (t) and a sensor reference signal Fstd (t). An A/D converter operates to A/D convert a difference signal Fsub (t) output from the difference amplifier to a discretized sensor signal. In the A/D conversion, a sampling frequency fs is set to satisfy the following relation: fc: fc=n·fs or fc=fs/2 (n is a natural number). Thus, the discretized sensor signal includes no carrier wave, and therefore a demodulation operation which has been previously essential can be simplified.
    Type: Grant
    Filed: November 7, 2007
    Date of Patent: March 16, 2010
    Assignee: Shimadzu Corporation
    Inventors: Junichiro Kozaki, Masaki Ohfuji
  • Patent number: 7564670
    Abstract: A magnetic bearing system for use in a vacuum pump including a motor provided with a rotary blade. The magnetic bearing system including a rotary shaft rotationally holding said rotor, a motor for rotationally driving said rotary shaft, a magnetic levitation section for supporting said rotor relative to a stator through said rotary shaft in a non-contact manner, a rotation detection section for detecting a rotational speed of said rotor, a rotor-temperature detection section for detecting a temperature of said rotor; a carrier-wave generation section for supplying a common carrier wave to each of a plurality of sensors provided in said magnetic levitation section, said rotation detection section and said rotor-temperature detection section, and an A/D conversion section for sampling a sensor signal output from each of said sensors, in synchronization with said carrier wave.
    Type: Grant
    Filed: April 30, 2007
    Date of Patent: July 21, 2009
    Assignee: Shimadzu Corporation
    Inventors: Junichiro Kozaki, Masaki Ohfuji, Nobuhiko Moriyama
  • Publication number: 20090028720
    Abstract: A vacuum pump capable of accurately detecting a rotor temperature based on a change in permeability of a magnetic material. Two targets are fixed to a nut opposed to a gap sensor. The nut is made of pure iron, and a surface of the nut opposed to the gap sensor serves as a target. The target has a Curie temperature greater than a temperature monitoring range, and each of the targets has a Curie temperature falling within the temperature monitoring range. When the targets become opposed to the gap sensor in turn according to rotation of a rotor, three types of signals are output from the gap sensor. The difference-signal generation means generates a difference signal of each the targets, on the basis of a signal of the target. The difference signal is compared with a reference signal V0 for detecting the Curie temperatures to detect a rotor temperature.
    Type: Application
    Filed: July 26, 2007
    Publication date: January 29, 2009
    Applicant: SHIMADZU CORPORATION
    Inventors: Yoshio Tsunazawa, Akira Arakawa, Junichiro Kozaki, Masaki Ohfuji
  • Patent number: 7417398
    Abstract: A vacuum pump includes at least one magnetic body located on a circle about a rotor rotational axis and having a Curie temperature within a rotor temperature monitoring range; an inductance detecting portion facing the circle so as to establish a gap between the circle and the inductance detecting portion, for detecting a change of magnetic permeability of the magnetic body as an inductance change when the magnetic body rotates; and a carrier generation device generating a carrier signal for providing in the inductance detecting portion. An A/D conversion device samples a detection signal of the inductance detecting portion synchronously with a carrier generation by the carrier generation device, and converts the detection signal to a digital signal. A determination device determines whether or not a temperature of the rotor exceeds a predetermined temperature, based on the change of the magnetic permeability of the magnetic body.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: August 26, 2008
    Assignee: Shimadzu Corporation
    Inventors: Junichiro Kozaki, Yoshio Tsunazawa, Akira Arakawa, Masaki Ohfuji
  • Publication number: 20080088398
    Abstract: Disclosed is a magnetic bearing system capable of simplifying a demodulation operation and reducing a processing load associated with a magnetic levitation control. A carrier signal having a frequency fc is apply to a sensor through a filter. The sensor operates to modulate the carrier signal, and a difference amplifier operates to calculate a difference between the amplitude-modulated signal FAM (t) and a sensor reference signal Fstd (t). An A/D converter operates to A/D convert a difference signal Fsub (t) output from the difference amplifier to a discretized sensor signal. In the A/D conversion, a sampling frequency fs is set to satisfy the following relation: fc: fc=n·fs or fc=fs/2 (n is a natural number). Thus, the discretized sensor signal includes no carrier wave, and therefore a demodulation operation which has been previously essential can be simplified.
    Type: Application
    Filed: November 7, 2007
    Publication date: April 17, 2008
    Applicant: SHIMADZU CORPORATION
    Inventors: Junichiro KOZAKI, Masaki OHFUJI
  • Publication number: 20070278884
    Abstract: Disclosed is a magnetic bearing system for use in a vacuum pump including a rotor provided with a rotary blade. The magnetic bearing system comprises a rotary shaft rotationally holding the rotor, a motor for rotationally driving the rotary shaft, a magnetic levitation section for supporting the rotor relative to a stator through the rotary shaft in a non-contact manner, a rotation detection section for detecting a magnetic pole position of the motor, a rotor-temperature detection section for detecting a temperature of the rotor, a carrier-wave generation section for supplying a common carrier wave to each of a plurality of sensors provided in the magnetic levitation section, the rotation detection section and the rotor-temperature detection section, and an A/D conversion section for sampling a sensor signal output from each of the sensors, in synchronization with the carrier wave.
    Type: Application
    Filed: April 30, 2007
    Publication date: December 6, 2007
    Applicant: SHIMADZU CORPORATION
    Inventors: Junichiro Kozaki, Masaki Ohfuji, Nobuhiko Moriyama
  • Publication number: 20070145929
    Abstract: A vacuum pump includes at least one magnetic body located on a circle about a rotor rotational axis and having a Curie temperature within a rotor temperature monitoring range; an inductance detecting portion facing the circle so as to establish a gap between the circle and the inductance detecting portion, for detecting a change of magnetic permeability of the magnetic body as an inductance change when the magnetic body rotates; and a carrier generation device generating a carrier signal for providing in the inductance detecting portion. An A/D conversion device samples a detection signal of the inductance detecting portion synchronously with a carrier generation by the carrier generation device, and converts the detection signal to a digital signal. A determination device determines whether or not a temperature of the rotor exceeds a predetermined temperature, based on the change of the magnetic permeability of the magnetic body.
    Type: Application
    Filed: November 30, 2006
    Publication date: June 28, 2007
    Applicant: SHIMADZU CORPORATION
    Inventors: Junichiro Kozaki, Yoshio Tsunazawa, Akira Arakawa, Masaki Ohfuji