Patents by Inventor Mitsuho Yoneyama

Mitsuho Yoneyama 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: 5486729
    Abstract: A controller of magnetic bearing controls the rotor speed with a reduced drive current while suppressing the rotor vibration. The controller implements the ABS control, N-cross control, N-straight control and FF control in proper combination in addition to the basic PID control. A computer in the controller determines the activation of each control in accordance with a predetermined table of control plan in response to the detected rotor speed.
    Type: Grant
    Filed: March 5, 1993
    Date of Patent: January 23, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Osami Matsushita, Mitsuho Yoneyama, Naohiko Takahashi, Yasuo Fukushima, Minoru Hiroshima, Tadashi Kaneki, Yoshiaki Abe, Naofumi Sakanashi
  • Patent number: 5408875
    Abstract: A balancing method for balancing a flexible rotor is disclosed. First, the rotor is rotated and vibration of the rotor is measured to determine resonance speeds. Vibration exciting forces of frequencies synchronized with the rotor rotation in two orthogonal directions are imparted to the rotor or rotor support bearings while rotating the rotor at a speed near the respective resonance speeds. The amplitude and the phase of the vibration exciting force which reduces the resonance vibration of the rotor are then determined. A correction weight on the basis of the amplitude and the phase of the vibration exciting force is then determined. Balancing work on the rotor such as grinding of the rotor or addition of a mass to the rotor in accordance with the correction weight is then carried out, followed by a rotor rotation conducted for the purpose of confirming the effect of the balancing work.
    Type: Grant
    Filed: May 20, 1992
    Date of Patent: April 25, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Osami Matsushita, Naohiko Takahashi, Mitsuho Yoneyama, Yasuo Fukushima, Minoru Hiroshima, Naohumi Sakanashi, Teturo Ohashi
  • Patent number: 5256952
    Abstract: A control method and apparatus for suppressing the vibration components of a magnetic bearing. According to this invention, a vibration wave is sampled at pulses synchronized with the rotation of a rotor, the vibration waveform sampled values at each revolution are averaged, and only the frequency components synchronized with the rotation frequency of the rotor are extracted from the vibration waveform. In addition, the extracted components are subjected to Fourier transform, processed in a frequency region and subjected to Fourier reverse transform. The sequence of these signal processes produces a signal, and the vibration components are suppressed by this signal.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: October 26, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Mitsuho Yoneyama, Osami Matsushita, Naohiko Takahashi, Yasuo Fukushima
  • Patent number: 4841212
    Abstract: In an electromagnetic bearing control apparatus for suppressing vibratory rotational motion of a rotor, a selective extraction unit is provided in servo-circuits which control currents being supplied to electromagnetic coils in accordance with x and y-component signals of radial displacement of the rotor such that the rotor is held in a predetermined radial position, and x and y-component signals delivered out of the selective extraction unit are crossed and inputted to the servo-circuits so as to be added in opposite polarities to processed x and y-component signals of radial displacement.
    Type: Grant
    Filed: August 12, 1987
    Date of Patent: June 20, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Osami Matsushita, Michiyuki Takagi, Mitsuho Yoneyama, Toyomi Sugaya, Ikuhiro Saito
  • Patent number: 4697128
    Abstract: The present invention reduces the resonance amplitude of the rotational frequency-synchronous unbalance vibration of a rotor supported by an electromagnetic bearing.To this end, the invention disposes an X-direction control servo circuit and a Y-direction control servo circuit each of which detects the deviation of the rotor from a desired position in the radial direction thereof and controls the rotor so as to be held at the desired position on the basis of the detection signal, and a tracking filter which is synchronous with the rotational frequency. Outputs from the filter are crossed to supply the Y-direction control servo circuit with the X-directional output and to supply the X-direction control servo circuit with the Y-directional output signal.
    Type: Grant
    Filed: May 8, 1986
    Date of Patent: September 29, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Osami Matsushita, Michiyuki Takagi, Mitsuho Yoneyama, Toyomi Sugaya