Patents by Inventor Mutsumi Muraoka

Mutsumi Muraoka 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: 20110180980
    Abstract: An active antivibration device which includes a main body, a mobile element which is elastically supported inside the main body and movable in an axial direction of the main body, and a coil which is disposed inside the main body and fixed to the main body. The mobile element includes a mobile axis body supported in the axial direction of the main body, and a first yoke, a permanent magnet and a second yoke which are held by the mobile axis body and disposed successively along an axial direction of the mobile axis body. The permanent magnet is magnetized in the axial direction of the mobile axis body and disposed between the first yoke and the second yoke.
    Type: Application
    Filed: January 28, 2011
    Publication date: July 28, 2011
    Applicants: KEIHIN CORPORATION, TOKAI RUBBER INDUSTRIES, LTD.
    Inventors: Atsushi URAYAMA, Hirozumi Kon, Hironori Koyama, Mutsumi Muraoka, Atsushi Muramatsu
  • Patent number: 7857293
    Abstract: A fluid filled type vibration damping device includes a fluid chamber divided by a partition member into a pressure-receiving chamber and an equilibrium chamber. The partition member has a first and a second member axially superposed together. A locking projection is formed on one of the first member or the second member and a locking hole is formed on an other, with the locking projection being inserted through the locking hole to effect locking so as to constitute a locking mechanism for holding the first and second member in a superposed state. Outer circumferential faces of the first member and the second member held in the superposed state by the locking mechanism are fastened fitting into a second mounting member via a seal rubber layer, and the first or second member having the locking hole includes a cover portion that covers an opening of the locking hole from a side thereof to which the locking projection projects.
    Type: Grant
    Filed: September 28, 2006
    Date of Patent: December 28, 2010
    Assignee: Tokai Rubber Industries, Ltd.
    Inventor: Mutsumi Muraoka
  • Publication number: 20100301530
    Abstract: A fluid-filled type active vibration damping device including a vibration damping device main unit, an oscillation member, and an actuator. The actuator is constituted by an electromagnetic actuator having a stator that includes a coil fixed to a second mounting member while having a movable member linearly displaceable relative to the stator when the coil is energized. A shaft member is provided for connecting the movable member and the oscillation member with each other. A connecting portion is provided for attaching the shaft member to the movable member while permitting the shaft member to tilt as well as to undergo displacement in an axis-perpendicular direction with respect to the movable member. A displacement preventing portion is provided for fastening the movable member and the shaft member to each other by preventing tilt as well as displacement in the axis-perpendicular direction due to the connecting portion.
    Type: Application
    Filed: May 25, 2010
    Publication date: December 2, 2010
    Applicants: TOKAI RUBBER INDUSTRIES, LTD., KEIHIN CORPORATION
    Inventors: Hironori Koyama, Koichi Hasegawa, Atsushi Muramatsu, Mutsumi Muraoka, Satoshi Umemura, Atsushi Urayama, Hirozumi Kon
  • Patent number: 7648129
    Abstract: A fluid filled vibration damping device including: a main rubber elastic body connecting first and second mounting members; a partition member and a fastening member axially superposed together and secured fitting into the second mounting member. The partition member has a recess on a side of the fastening member, where an annular mounting fitting having a flange portion is inserted with a seal rubber projection disposed on one axial end thereof and projecting axially outward from the flange portion pressed fluid-tightly in an axial direction against the partition member around an entire circumference. An other axial end of the mounting fitting is fastened fluid-tightly onto a mating projection portion formed on the fastening member via a seal rubber layer. A diametrical gap is formed between an inside face of the recess of the partition member and the flange portion of the mounting fitting as well as the seal rubber projection.
    Type: Grant
    Filed: December 8, 2006
    Date of Patent: January 19, 2010
    Assignee: Tokai Rubber Industries, Ltd.
    Inventor: Mutsumi Muraoka
  • Patent number: 7584945
    Abstract: A vibration damping device including a first and a second mounting member connected together by an elastic body, comprising a rebound abutting portion of flange shape integrally formed on the first mounting member; a tubular bracket fastened about the second mounting member; a stopper abutting portion formed at the tubular bracket; and a cushioning rubber disposed on the rebound abutting portion to constitute a rebound stopper mechanism for limiting relative displacement in an axially away direction between the first and second mounting members, wherein a first rotation preventing mechanism for preventing rotation of the first mounting member about a center axis of the tubular bracket by means of abutting contact of a pair of first abutting faces formed on the cushioning rubber against a pair of first abutted faces formed on a mating tube portion of the tubular bracket.
    Type: Grant
    Filed: July 19, 2006
    Date of Patent: September 8, 2009
    Assignee: Tokai Rubber Industries, Ltd.
    Inventors: Hajime Maeno, Mutsumi Muraoka
  • Publication number: 20090079114
    Abstract: A vibration damping device including: a rubber elastic body connecting first and second mounting members; a partition member supported on the second mounting member; a pressure-receiving chamber and an equilibrium chamber connected by a first orifice passage; an oscillating plate defining the pressure-receiving chamber; and an electromagnetic actuator for actuating the oscillating plate. The oscillating plate is constituted by a cylinder shaped hole and a piston shaped plate accommodated within the cylinder shaped hole with a gap provided therebetween. An output member of the electromagnetic actuator is linked to the piston shaped plate. A plate spring extending in an axis-perpendicular direction is disposed to an opposite side from the electromagnetic actuator with the piston shaped plate therebetween, with the oscillating plate linked to and supported in an axial direction with respect to the partition member by the plate spring.
    Type: Application
    Filed: September 18, 2008
    Publication date: March 26, 2009
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventor: Mutsumi Muraoka
  • Publication number: 20090079118
    Abstract: A vibration damping device including: a pressure-receiving chamber and an equilibrium chamber connected by a first orifice passage; a movable member disposed within the pressure-receiving chamber, to form a primary fluid chamber partly defined by a rubber elastic body, and an auxiliary fluid chamber partly defined by an oscillating plate; and a second orifice passage connecting the auxiliary fluid chamber to the equilibrium chamber. A through-hole is formed in a partition member that partitions the primary fluid chamber and the auxiliary fluid chamber, the oscillating plate is housed within the through-hole with a gap provided therebetween whereby the oscillating plate is displaceable in an axial direction within the through-hole. A stopper abutted by the oscillating plate during displacement to one axial side is provided, with the gap becoming closed off when the oscillating plate is in a state of abutment against the stopper.
    Type: Application
    Filed: September 18, 2008
    Publication date: March 26, 2009
    Applicant: TOKAI RUBBER INDUSTRIES, LTD .
    Inventors: Mutsumi MURAOKA, Hironori KOYAMA
  • Publication number: 20090001639
    Abstract: A fluid filled type vibration damping device having a pressure-receiving chamber and an equilibrium chamber disposed on either side of a partition member. A movable cover member juxtaposed against the partition member from the pressure receiving chamber side to cover a communicating hole of the partition member. An outside peripheral edge of the movable cover member is held in intimate contact against the partition member through urging force of an elastic retainer portion. Pressure of both chambers will acts on both faces of a movable rubber film, thereby constituting a pressure fluctuation absorbing mechanism. The outside peripheral edge of the movable cover member is separated from the partition member in opposition to the urging force by negative pressure in the pressure receiving chamber for providing a shunting mechanism for preventing excessive negative pressure in the pressure receiving chamber.
    Type: Application
    Filed: June 18, 2008
    Publication date: January 1, 2009
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventors: Mutsumi Muraoka, Satoshi Umemura
  • Patent number: 7350776
    Abstract: A fluid-filled type vibration-damping device having an elastic rubber film partially defining a primary fluid chamber at one surface and partially defining a pressure action chamber. The pressure action chamber varies its pressure under control so that the elastic rubber film changes its elasticity to change damping characteristics of the device. To give sufficient recovery force for the elastic rubber film, the elastic rubber film includes a plurality of thick reinforcing ribs circumferentially spaced apart from one another and extending in a radial direction from an outside peripheral edge over a length not reaching a center so that areas situated between pairs of adjacent reinforcing ribs constitutes thin portions formed by a thin rubber elastic body, while the center portion of the elastic rubber film situated between distal ends constitutes a bowed center portion thinner than the reinforcing ribs and convex towards the pressure action chamber.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: April 1, 2008
    Assignee: Tokai Rubber Industries, Ltd.
    Inventors: Atsushi Muramatsu, Hajime Maeno, Mutsumi Muraoka, Hironori Koyama
  • Patent number: 7344128
    Abstract: A fluid-filled type vibration-damping device having a movable rubber plate housed within a partition member partitioning a pressure-receiving chamber and an equilibrium chamber from each other. The movable rubber plate is moved owing to the pressure difference between the two chambers. The movable rubber plate comprises the movable rubber plate formed of a generally disk shaped rubber elastic body having formed thereon in alternating fashion concave grooves and convex ribs each extending in a circumferential direction about a same center axis, the convex ribs have tapered cross section gradually narrowing in width towards an distal end thereof, and the concave grooves and convex ribs are disposed at the same locations in a diametrical direction on either face of the movable rubber plate so that the thickness of the movable rubber plate is varied in the circumferential direction.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: March 18, 2008
    Assignee: Tokai Rubber Industries, Ltd.
    Inventors: Atsushi Muramatsu, Hajime Maeno, Mutsumi Muraoka, Hironori Koyama, Satoshi Umemura
  • Publication number: 20080023897
    Abstract: A fluid filled type vibration damping device wherein an elastic rubber film is disposed to partially define a primary fluid chamber disposed on one side thereof, and a pressure operating chamber is disposed on an opposite side from the primary fluid chamber with the elastic rubber film interposed therebetween. The elastic rubber film has a dome shape and an attraction face of the pressure operating chamber has an inverted dome shape, and has a negative pressure suction groove including an outer circumferential groove extending in a circumferential direction at an outer peripheral portion of the attraction face and opening to the pressure operating chamber, and a negative pressure suction bore for introducing a negative pressure to the pressure operating chamber is connected to the negative pressure suction groove.
    Type: Application
    Filed: July 24, 2007
    Publication date: January 31, 2008
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventor: Mutsumi Muraoka
  • Patent number: 7255335
    Abstract: A fluid-filled active damping apparatus having a pressure receiving chamber partially defined by a rubber elastic body connecting a first and second mounting member; an oscillation plate defining a part of the pressure receiving chamber, and supported in a displaceable fashion; an electromagnetic actuator disposed on one side of the oscillation plate remote from the pressure receiving chamber, with its output member connected to the oscillation plate; an equilibrium chamber partially defined by a flexible diaphragm; and an orifice passage connecting the pressure receiving chamber and equilibrium chamber. A rigid annular guide member is disposed about the oscillation plate with a slight gap therebetween, such that these members are mutually displaceable in the axial direction. The guide member is elastically supported by and connected to the second mounting member via an elastic support member.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: August 14, 2007
    Assignee: Tokai Rubber Industries, Ltd.
    Inventors: Mutsumi Muraoka, Atsushi Muramatsu
  • Publication number: 20070138718
    Abstract: A fluid filled vibration damping device including: a main rubber elastic body connecting first and second mounting members; a partition member and a fastening member axially superposed together and secured fitting into the second mounting member. The partition member has a recess on a side of the fastening member, where an annular mounting fitting having a flange portion is inserted with a seal rubber projection disposed on one axial end thereof and projecting axially outward from the flange portion pressed fluid-tightly in an axial direction against the partition member around an entire circumference. An other axial end of the mounting fitting is fastened fluid-tightly onto a mating projection portion formed on the fastening member via a seal rubber layer. A diametrical gap is formed between an inside face of the recess of the partition member and the flange portion of the mounting fitting as well as the seal rubber projection.
    Type: Application
    Filed: December 8, 2006
    Publication date: June 21, 2007
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventor: Mutsumi Muraoka
  • Publication number: 20070090578
    Abstract: A fluid filled type vibration damping device includes a fluid chamber divided by a partition member into a pressure-receiving chamber and an equilibrium chamber. The partition member has a first and a second member axially superposed together. A locking projection is formed on one of the first member or the second member and a locking hole is formed on an other, with the locking projection being inserted through the locking hole to effect locking so as to constitute a locking mechanism for holding the first and second member in a superposed state. Outer circumferential faces of the first member and the second member held in the superposed state by the locking mechanism are fastened fitting into a second mounting member via a seal rubber layer, and the first or second member having the locking hole includes a cover portion that covers an opening of the locking hole from a side thereof to which the locking projection projects.
    Type: Application
    Filed: September 28, 2006
    Publication date: April 26, 2007
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventor: Mutsumi Muraoka
  • Publication number: 20070052142
    Abstract: A vibration damping device including: an elastic body of frustoconical shape; a first mounting member superposed against a small diameter end face of the elastic body; a second mounting member affixed to an outer circumferential face of a large-diameter end portion of the elastic body; and a rebound stopper mechanism for cushion-wise limitation of relative displacement of the first and second mounting members in a direction of moving apart. At least one of superposed faces of the first mounting member and the rubber elastic body is provided with a seal lip at an outside peripheral portion thereof so as to project outward therefrom and extend over an entire circumference thereof.
    Type: Application
    Filed: September 1, 2006
    Publication date: March 8, 2007
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventor: Mutsumi Muraoka
  • Publication number: 20070018366
    Abstract: A vibration damping device including a first and a second mounting member connected together by an elastic body, comprising a rebound abutting portion of flange shape integrally formed on the first mounting member; a tubular bracket fastened about the second mounting member; a stopper abutting portion formed at the tubular bracket; and a cushioning rubber disposed on the rebound abutting portion to constitute a rebound stopper mechanism for limiting relative displacement in an axially away direction between the first and second mounting members, wherein a first rotation preventing mechanism for preventing rotation of the first mounting member about a center axis of the tubular bracket by means of abutting contact of a pair of first abutting faces formed on the cushioning rubber against a pair of first abutted faces formed on a mating tube portion of the tubular bracket.
    Type: Application
    Filed: July 19, 2006
    Publication date: January 25, 2007
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventors: Hajime Maeno, Mutsumi Muraoka
  • Patent number: 7165761
    Abstract: A fluid filled active vibration damping device wherein a first and a second mounting member are coupled by a rubber elastic body, thereby forming a pressure receiving chamber defined at one part by the rubber elastic body, with a non-compressible fluid sealed therein, and at another part by an excitation plate capable of displacement. An electromagnetic actuating assembly are disposed on the pressure receiving chamber side with the excitation plate therebetween. The excitation plate is oscillated by application of electronical current to a coil member in the electromagnetic actuating assembly. The output member projects out towards the excitation plate from the electromagnetic actuating assembly, and a permanent magnet is disposed in the output member and/or the excitation plate in order to couple the output member and the excitation plate through magnetic force.
    Type: Grant
    Filed: September 8, 2005
    Date of Patent: January 23, 2007
    Assignee: Tokai Rubber Industries, Ltd.
    Inventors: Mutsumi Muraoka, Atsushi Muramatsu
  • Publication number: 20060220287
    Abstract: A fluid-filled type vibration-damping device having a movable rubber plate housed within a partition member partitioning a pressure-receiving chamber and an equilibrium chamber from each other. The movable rubber plate is moved owing to the pressure difference between the two chambers. The movable rubber plate comprises the movable rubber plate formed of a generally disk shaped rubber elastic body having formed thereon in alternating fashion concave grooves and convex ribs each extending in a circumferential direction about a same center axis, the convex ribs have tapered cross section gradually narrowing in width towards an distal end thereof, and the concave grooves and convex ribs are disposed at the same locations in a diametrical direction on either face of the movable rubber plate so that the thickness of the movable rubber plate is varied in the circumferential direction.
    Type: Application
    Filed: March 9, 2006
    Publication date: October 5, 2006
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventors: Atsushi Muramatsu, Hajime Maeno, Mutsumi Muraoka, Hironori Koyama, Satoshi Umemura
  • Publication number: 20060208405
    Abstract: A fluid-filled type vibration-damping device having an elastic rubber film partially defining a primary fluid chamber at one surface and partially defining a pressure action chamber. The pressure action chamber varies its pressure under control so that the elastic rubber film changes its elasticity to change damping characteristics of the device. To give sufficient recovery force for the elastic rubber film, the elastic rubber film includes a plurality of thick reinforcing ribs circumferentially spaced apart from one another and extending in a radial direction from an outside peripheral edge over a length not reaching a center so that areas situated between pairs of adjacent reinforcing ribs constitutes thin portions formed by a thin rubber elastic body, while the center portion of the elastic rubber film situated between distal ends constitutes a bowed center portion thinner than the reinforcing ribs and convex towards the pressure action chamber.
    Type: Application
    Filed: March 9, 2006
    Publication date: September 21, 2006
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventors: Atsushi Muramatsu, Hajime Maeno, Mutsumi Muraoka, Hironori Koyama
  • Publication number: 20060055095
    Abstract: A fluid filled active vibration damping device wherein a first and a second mounting member are coupled by a rubber elastic body, thereby forming a pressure receiving chamber defined at one part by the rubber elastic body, with a non-compressible fluid sealed therein, and at another part by an excitation plate capable of displacement. An electromagnetic actuating assembly are disposed on the pressure receiving chamber side with the excitation plate therebetween. The excitation plate is oscillated by application of electronical current to a coil member in the electromagnetic actuating assembly. The output member projects out towards the excitation plate from the electromagnetic actuating assembly, and a permanent magnet is disposed in the output member and/or the excitation plate in order to couple the output member and the excitation plate through magnetic force.
    Type: Application
    Filed: September 8, 2005
    Publication date: March 16, 2006
    Applicant: TOKAI RUBBER INDUSTRIES, LTD.
    Inventors: Mutsumi Muraoka, Atsushi Muramatsu