Patents by Inventor Kiyofumi Hirai

Kiyofumi Hirai 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: 5163884
    Abstract: A friction-type stepless speed change device includes a frictional transmission elements composed of a pair of driving discs connected to an input shaft, and an annular driven disc connected to an output shaft and embraced between and urged against opposite conical surfaces of the driving discs into wedge-engagement to generate frictional force and allow power transmission from the driving discs to the driven disc. The driving discs are at a variable eccentricity relative to the driven disc, with which an effective pitch diameter of the driving discs is varied to effect a stepless speed change. For reducing the size of the frictional transmission elements while preserving a required torque capacity, the device further comprises a driving rotary unit for transmitting power from the input shaft to the driving discs at an increased rotational speed, and a driven rotary unit for transmitting power from the driven disc to the output shaft at a reduced rotational speed.
    Type: Grant
    Filed: May 1, 1991
    Date of Patent: November 17, 1992
    Assignee: Bridgestone Cycle Co., Ltd.
    Inventors: Kikuzo Takamiya, Yoshitaka Tamura, Nobuaki Shimada, Kiyofumi Hirai
  • Patent number: 5056630
    Abstract: A wheel rim for a two-wheeled vehicle has a spray coated metallic and/or ceramic layer covering at least a part of a rim surface with which a brake shoe is brought into contact when a brake is applied.
    Type: Grant
    Filed: March 7, 1989
    Date of Patent: October 15, 1991
    Assignees: Bridgestone Corporation, Bridgestone Cycle Co., Ltd.
    Inventors: Yoshihiko Fujii, Bunji Mutoh, Yoshitaka Tamura, Kiyofumi Hirai
  • Patent number: 5045037
    Abstract: A friction stepless speed change device includes an input shaft, a driven shaft and an output shaft arranged on a common axis, and a countershaft rotatably provided in parallel with the common axis. The device further includes tow rockable arms rockable about the countershaft, a cylindrical driving rotary assembly rotatably provided on free ends of the rockable arms to enclose the driven shaft, a set of driving friction discs rotating together with the driving rotary assembly, and a set of driven friction discs rotating together with the driven shaft. The countershaft includes a first gear in mesh with a gear fixed to the input shaft, a second gear in mesh with a gear fixed to the driving rotary assembly, and a third gear in mesh with a sun gear of a planetary gear provided on the driven shaft. The output shaft is integrally formed with an internal gear in mesh with planet gears of the planetary gear.
    Type: Grant
    Filed: June 27, 1990
    Date of Patent: September 3, 1991
    Assignee: Bridgestone Cycle Co., Ltd.
    Inventors: Kikuzo Takamiya, Yoshitaka Tamura, Kiyofumi Hirai
  • Patent number: 5030183
    Abstract: A friction stepless speed change device includes an input shaft, an output shaft, a countershaft provided in parallel with the input and output shafts on one side thereof, two rocking arms rockable about the countershaft, a cylindrical driven rotary assembly rotatably supported on free ends of the rocking arms to enclose the input shaft, a set of driving friction discs rotating together with the input shaft, and a set of driven friction discs rotating together with the driven rotary assembly. The sets of the driving and driven friction discs are wedge-engaged with each other. A gear fixed to the driven rotary assembly is in mesh with one gear of an intermediate gear assembly, and a gear arranged on a planet carrier is in mesh with the other gear of the intermediate gear assembly. Planet gears journaled on the planet carrier are in mesh with an internal gear integrally fixed to the input shaft, and a sun gear integrally formed on the output shaft is in mesh with the planat gears.
    Type: Grant
    Filed: June 8, 1990
    Date of Patent: July 9, 1991
    Assignee: Bridgestone Cycle Co., Ltd.
    Inventors: Kikuzo Takamiya, Yoshitaka Tamura, Kiyofumi Hirai
  • Patent number: 4934205
    Abstract: The invention relates to a stepless speed change device which comprises: an input shaft and an output shaft concentric to each other, a disc progressively thinner toward its outer periphery and fixed to the input shaft, a hollow cylinder fixed to the output shaft for enclosing the disc, a ring progressively thinner toward its inner periphery opposite to that of the disc and fixed to an inner circumference of the hollow cylinder in the same plane as that of the disc, and an intermediate transmitting device having two discs for embracing the ring and the disc on both sides thereof and being movable from a concentric position with the input and output shafts to eccentric positions with desired eccentricities therefrom in a stepless manner. With the above arrangement, the input shaft may be used as an output shaft, and the output shaft may be used as an input shaft.
    Type: Grant
    Filed: December 14, 1988
    Date of Patent: June 19, 1990
    Assignee: Bridgestone Cycle Co., Ltd.
    Inventors: Kikuzo Takamiya, Yoshitaka Tamura, Kiyofumi Hirai
  • Patent number: 4931796
    Abstract: In a digital-to-analog conversion circuit, a level detector is used to determine when the digital signal is lower than a predetermined value. When a predetermined time has expired, after the level detection, an inversion detector detects an inversion in polarity of the digital signal. As a result, a control signal is produced to shift the digital signal input to the digital-to-analog (D/A) converter and to attenuate the output analog signal.
    Type: Grant
    Filed: November 16, 1988
    Date of Patent: June 5, 1990
    Assignee: Pioneer Electronic Corporation
    Inventors: Yoshinori Hasegawa, Kiyofumi Hirai
  • Patent number: 4920827
    Abstract: A stepless speed change device has an input shaft and an output shaft. The device inlcudes a planetary carrier proviced at an inner end of the input shaft, a sun gear provided at an inner end of the output shaft to be in mesh with planet gears carried on the planetary carrier, and an internal gear in mesh with the planet gears to form a planetary gear. The device further includes a driven rotor rotatable about the input shaft and in the form of a hollow cylinder having flanges at both ends and concentrically connected to the internal gear, a driving rotor enclosing the driven rotor and including two members connected to the input shaft on both sides of the driven rotor, and an intermediate friction transmission ring whose eccentricity is adjustable and interposed between the flanges of the driven rotor and between the two members of the driving rotor for transmitting rotating power therebetween.
    Type: Grant
    Filed: February 28, 1989
    Date of Patent: May 1, 1990
    Assignee: Bridgestone Cycle Co., Ltd.
    Inventors: Kikuzo Takamiya, Yoshitaka Tamura, Yoichi Shibayama, Ritsuo Nishimura, Kiyofumi Hirai, Hiromitsu Serizawa