Patents by Inventor Ken Enami

Ken Enami 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: 5661382
    Abstract: A circuit to drive a brushless motor which consumes less power because it uses pulse width modulation. The invention has at least two loops; one loop to control the switching of transistors in a push-pull configuration drives current in the different coils of the motor when those transistors connected to ground are driven in a linear, rather than a saturated, mode. This loop also incorporates a soft switching waveform shaping circuit which slowly switches the phase current so that the electromagnetic noise of the motor does not enter the magnetic head on the disk. The other loop actually controls the speed of the motor based on the linear mode of the transistors.
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: August 26, 1997
    Assignee: International Business Machines Corporation
    Inventors: Ken Enami, Satoshi Yamamoto
  • Patent number: 4623939
    Abstract: A rotation control apparatus for a motor comprises a motor for rotating or moving a recording medium, a circuit for generating first and second reference signals, a circuit for passing a signal which is obtained by comparing phases of the first reference signal and a synchronizing signal through a filter circuit thereof so as to produce a first error signal therefrom, a circuit for producing a second error signal which is obtained by comparing phases of the second reference signal and the rotation detection signal, and a control circuit for controlling first and second switching circuits. The control circuit supplies a specific signal having a level dependent on the level of the second error signal to a capacitor of the filter circuit through the second switching circuit and selectively passes the second error signal through the first switching circuit when the motor rotates at a rotational speed which is not near a steady state rotational speed.
    Type: Grant
    Filed: November 21, 1984
    Date of Patent: November 18, 1986
    Assignee: Victor Company of Japan, Ltd.
    Inventors: Toyotaka Machida, Ken Enami
  • Patent number: 4572995
    Abstract: A synchronism discriminating circuit comprises a phase comparator supplied with a reference signal having a reference frequency and a reference phase and with an input signal of which a synchronism with respect to the reference signal is to be discriminated, for comparing the phase of the reference signal with the phase of the input signal and for producing an output signal responsive to a phase difference between the two signals, where the reference signal is made up of a series of pulses, and a discriminating circuit supplied with the reference signal and with the output signal of the phase comparator, for counting the pulses in the reference signal during a period in which the phase difference is within a predetermined range and for producing a synchronism discrimation signal when a predetermined number or more pulses in the reference signal are continuously counted.
    Type: Grant
    Filed: August 8, 1984
    Date of Patent: February 25, 1986
    Assignee: Victor Company of Japan, Ltd.
    Inventor: Ken Enami
  • Patent number: 4542423
    Abstract: A rotation control device causes a disc on which information and sync signals are recorded to rotate at a predetermined speed. The control device includes a generator for generating a signal whose frequency is identical with that of a rotation signal which will be output from a frequency generator while the disc rotates at the predetermined speed. A control loop is defined which compares a phase of an output of the signal generator and a rotation signal output from the frequency generator, thereby controlling the drive of the motor.
    Type: Grant
    Filed: October 12, 1983
    Date of Patent: September 17, 1985
    Assignee: Victor Company of Japan
    Inventors: Eiichi Kotake, Ken Enami, Kinzo Wada
  • Patent number: 4504881
    Abstract: A protective circuit for an electric motor comprises a frequency signal generating circuit for generating a frequency signal in accordance with the rotational speed of the motor, a switching circuit switched over to either permit or cut off supply of current to the motor, and a detecting circuit for detecting that the period of the generated frequency signal has become larger than a predetermined period due to a decrease in the rotational speed of the motor, and cutting off the supply of current to the motor by the switching circuit.
    Type: Grant
    Filed: December 10, 1982
    Date of Patent: March 12, 1985
    Assignee: Victor Company of Japan, Ltd.
    Inventors: Kinzo Wada, Ken Enami
  • Patent number: 4417186
    Abstract: A commutatorless electrical motor comprises a cylindrical magnetic rotor having main magnetic poles where N and S poles are alternately arranged in the circumferential direction, and an axis of N and S poles of each magnet extends radially, and a sub magnetic poles at one end of the cylindrical rotor. The sub magnetic poles are arranged such that N and S poles of each magnetized area extends axially. The magnetized area providing each sub magnetic pole has an arcuate extent of .pi./2 or less in an electrical angle. Each of the magnetized area providing each sub magnetic pole makes a given change in the magnetic flux density distribution in the vicinity of rotational position detecting elements so that the rotational position of the rotor can be accurately detected.
    Type: Grant
    Filed: January 12, 1982
    Date of Patent: November 22, 1983
    Assignee: Victor Company of Japan, Limited
    Inventors: Yukimi Hirose, Ken Enami, Kinzo Wada