Patents by Inventor Mikio Yamashita

Mikio Yamashita 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: 20150204412
    Abstract: In a friction member (22), a base section (92) is constituted by a bottom section (101) and a tube section (102). The bottom section (101) has a bored disk shape, and the tube section (102) has a cylindrical shape extending from an outer circumferential side of the bottom section (101) in the axial direction. An elastic rubber section (91) has a minimum inner diameter section (137), diameter expanding sections (138), (139) which are disposed at each side in the axial direction of the minimum inner diameter section (137). A tube section adhering surface (126) is installed at outer circumferential side of a tube section (102). A cutout section (151) is at least partially formed at a bottom section adhering surface (128) fixed to the bottom section (101) and the tube section (102) side of an open surface at an opposite side in the axial direction, and a deepest section (155) of the cutout section (151) is shallower than a position in the axial direction of the minimum inner diameter section (137).
    Type: Application
    Filed: July 25, 2013
    Publication date: July 23, 2015
    Applicant: Hitachi Automotive Systems, Ltd.
    Inventors: Mikio Yamashita, Toru Hosokawa
  • Patent number: 9062734
    Abstract: A shock absorber includes a first and a second passage configured to flow a working fluid out of one chamber by movement of a piston, a first damping force generation mechanism installed at the first passage and configured to generate a damping force, a housing having at least a partial passage of the second passage formed therein, a free piston movably installed in the housing and configured to partition the second passage into an upstream side and a downstream side, and a spring member disposed in the housing and configured to hole the free piston at a neutral position, wherein a second damping force generation mechanism including a friction member installed at an inner side of the cylinder with respect to the sealing member and constituted by an annular elastic rubber section in sliding contact with the piston rod and an annular base section to which the elastic rubber section is fixed and a communication passage configured to reduce a pressure difference between both sides in an axial direction of the fri
    Type: Grant
    Filed: February 25, 2013
    Date of Patent: June 23, 2015
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Mikio Yamashita, Atsushi Maeda
  • Publication number: 20150041265
    Abstract: A damping force generating mechanism is housed in a casing disposed at a side of an outer tube of a tube type shock absorber and secured by tightening a nut. The damping force generating mechanism is connected through a passage member to a branch pipe of a separator tube forming an annular passage communicating with a cylinder. The passage member has support portions formed on an abutting surface abutting against a main body. The support portions are disposed at the inner peripheral side of a seal groove on the abutting surface so as to abut directly against the main body. As the nut is tightened, an axial force is transmitted to the support portions from the center and its vicinities of the main body, causing a flange portion of the passage member to be pressed against a flange portion of the casing, thereby securing the passage member.
    Type: Application
    Filed: July 31, 2014
    Publication date: February 12, 2015
    Inventor: Mikio YAMASHITA
  • Publication number: 20140353099
    Abstract: For the extension and compression strokes of a piston rod, a damping force generating mechanism generates a damping force by controlling the flow of hydraulic oil caused by the sliding movement of a piston in a cylinder. The damping force generating mechanism has a pilot-type main valve, a pilot-type control valve, and a pilot valve. The main valve has a pilot chamber into which the oil is introduced to adjust the valve-opening pressure of the main valve by the pressure in the pilot chamber. The control valve has a pilot chamber into which the oil is introduced to adjust the valve-opening pressure of the control valve by the pressure in the pilot chamber. The pilot valve controls the pressure in the pilot chamber of the control valve. The control valve controls the pressure in the pilot chamber of the main valve.
    Type: Application
    Filed: March 25, 2014
    Publication date: December 4, 2014
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Mikio YAMASHITA, Shunsuke MORI
  • Patent number: 8833532
    Abstract: A shock absorber includes a piston partitioning an inside of a cylinder into a rod-side chamber and a bottom-side chamber, a piston rod having a first end connected to the piston and a second end extending to an outside of the cylinder, a housing provided on the first end side of the piston rod, a free piston slidably inserted into the housing, a rod passage allowing the rod-side chamber to communicate with a pressure chamber within the housing, and damping valves provided in passages allowing the rod-side chamber to communicate with the bottom-side chamber. The free piston is provided with a shutter member that adjusts the opening area of a pressure chamber opening of the rod passage according to a movement of the free piston.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: September 16, 2014
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventor: Mikio Yamashita
  • Publication number: 20140252735
    Abstract: A shock absorber includes a first passage (111) or (112) and a second passage (32), (99) or (235) in communication with each other and configured to allow a working fluid to flow between two chambers (16) and (17) based on movement of a piston (15), and a passage area adjustment mechanism (101) or (236) configured to adjust a passage area of the second passage (99) or (235) depending on a position of a piston rod (18) is installed to have at least one of a maximum length-side property in which an extension-side damping force becomes soft and a compression-side damping force becomes hard in a range in which the piston rod (18) extends to an outside of a cylinder (11) farther than a maximum length-side predetermined position, and a minimum length-side property in which the extension-side damping force becomes hard and the compression-side damping force becomes soft in a range in which the piston rod (18) enters an inside of the cylinder (11) further than a minimum length side predetermined position.
    Type: Application
    Filed: November 28, 2012
    Publication date: September 11, 2014
    Inventors: Mikio Yamashita, Fumiyuki Yamaoka, Masaru Kouyama, Kunio Takiguchi, Atsufumi Ishimoto
  • Publication number: 20140238796
    Abstract: A shock absorber includes a first and a second passage configured to flow a working fluid out of one chamber by movement of a piston, a first damping force generation mechanism installed at the first passage and configured to generate a damping force, a housing having at least a partial passage of the second passage formed therein, a free piston movably installed in the housing and configured to partition the second passage into an upstream side and a downstream side, and a spring member disposed in the housing and configured to hole the free piston at a neutral position, wherein a second damping force generation mechanism including a friction member installed at an inner side of the cylinder with respect to the sealing member and constituted by an annular elastic rubber section in sliding contact with the piston rod and an annular base section to which the elastic rubber section is fixed and a communication passage configured to reduce a pressure difference between both sides in an axial direction of the fri
    Type: Application
    Filed: February 25, 2013
    Publication date: August 28, 2014
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Mikio YAMASHITA, Atsushi MAEDA
  • Publication number: 20140231201
    Abstract: A shock absorber has an inclined surface that is inclined to a moving direction of the free piston in at least one of a free piston contact surface of a free piston with which an elastic body is in contact and a housing contact surface of a housing with which the elastic body is in contact. A shortest distance between the free piston contact surface and the housing contact surface is changed by movement of the free piston.
    Type: Application
    Filed: April 29, 2014
    Publication date: August 21, 2014
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: ATSUSHI MAEDA, MASARU KOUYAMA, MIKIO YAMASHITA, FUMIYUKI YAMAOKA
  • Patent number: 8794405
    Abstract: Oil grooves of a shutter and oil holes of a stepped rod constitute first orifices as variable orifices whose opening areas are variable according to the rotational position of the shutter. The oil grooves of the shutter and oil holes of the stepped rod constitute third orifices as variable orifices. Cut portions of inner disk valves constitute second orifices. The opening areas of the variable orifices are changed by rotating the shutter, thereby controlling damping force characteristics in a low piston speed region and the relief pressures of pressure control valves independently of each other, and thus increasing the degree of freedom for adjusting the damping force characteristics.
    Type: Grant
    Filed: December 28, 2011
    Date of Patent: August 5, 2014
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Mikio Yamashita, Fumiyuki Yamaoka
  • Patent number: 8746423
    Abstract: A shock absorber has an inclined surface that is inclined to a moving direction of the free piston in at least one of a free piston contact surface of a free surface with which an elastic body is in contact and a housing contact surface of a housing with which the elastic body is in contact. A shortest distance between the free piston contact surface and the housing contact surface is changed by movement of the free piston.
    Type: Grant
    Filed: February 28, 2011
    Date of Patent: June 10, 2014
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Atsushi Maeda, Masaru Kouyama, Mikio Yamashita, Fumiyuki Yamaoka
  • Patent number: 8695766
    Abstract: A shock absorber includes first passages configured to communicate two chambers to flow a working fluid therebetween by movement of a piston, and a second passage configured to communicate with one chamber of the two chambers. The first passages have damping valves configured to suppress a flow of the working fluid generated by movement of the piston to generate a damping force. The second passage has a variable orifice having an area adjusted by an elastic member when a piston rod moves in an extension direction, a pressure chamber installed in series with the variable orifice, and a free piston configured to vary a volume of the pressure chamber by movement of the piston.
    Type: Grant
    Filed: March 19, 2012
    Date of Patent: April 15, 2014
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Mikio Yamashita, Fumiyuki Yamaoka, Masaru Kouyama, Atsushi Maeda
  • Patent number: 8651252
    Abstract: A frequency-dependent mechanism provided at the lower end of a piston rod includes a tubular housing displaceable in an inner tube, together with the piston rod as one unit, and further includes a free piston and O-rings. A shutter of a passage area varying mechanism is provided with an axially extending inner hole, orifices, and oil grooves. The opening area between oil holes 3C and the orifices 33B is changed according to the rotational position of the shutter. The opening area between oil holes 3D and 3E and the oil grooves 33C and 33D and the opening area between oil holes 3F and 3G and the oil grooves 33E and 33F are also variably adjusted according to the rotational position of the shutter.
    Type: Grant
    Filed: December 28, 2011
    Date of Patent: February 18, 2014
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Yohei Katayama, Takao Nakadate, Kenji Noda, Mikio Yamashita, Fumiyuki Yamaoka
  • Patent number: 8622689
    Abstract: A rotor drive mechanism and pump apparatus according to the present invention may cause an external screw type rotor of a uniaxial eccentric screw pump to rotate and carry out a revolution movement. The rotor drive mechanism further comprises a shaft sealing structure configured such that a gap between an outer peripheral portion of an end portion of the revolution shaft is located on the external screw type rotor side and an inner peripheral portion of the casing in the pump apparatus is sealed. The rotor drive mechanism provides for a reduced amount of heat and vibrations to be generated when the rotor is rotated at high speed and further allows for lowering of contact pressure between an outer surface of the rotor and an inner surface of a stator inner hole.
    Type: Grant
    Filed: August 8, 2008
    Date of Patent: January 7, 2014
    Assignee: Heishin Sobi Kabushiki Kaisha
    Inventors: Teruaki Akamatsu, Mikio Yamashita, Nobuhisa Suhara
  • Patent number: 8590680
    Abstract: A shock absorber includes a first passage and a second passage to which a working fluid flows out from one chamber in a cylinder by movement of a piston, a damping valve installed on the first passage and configured to regulate a flow of the working fluid caused by sliding of the piston to generate a damping force, a back pressure chamber applying an internal pressure to the damping valve in a closing direction of the damping valve, a back pressure chamber inflow oil passage introducing the working fluid from one chamber into the back pressure chamber, a pressure chamber provided in-between on the second passage, and a free piston installed in the pressure chamber so as to freely slide in the pressure chamber.
    Type: Grant
    Filed: February 28, 2011
    Date of Patent: November 26, 2013
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Atsushi Maeda, Masaru Kouyama, Mikio Yamashita, Fumiyuki Yamaoka
  • Patent number: 8449275
    Abstract: A pump apparatus includes a first rotor drive mechanism configured to transfer rotation of an input shaft portion to an output shaft portion coupled to an external screw type rotor of a uniaxial eccentric screw pump, the input shaft portion being rotated with a central axis thereof kept in a certain position, and a uniaxial eccentric screw pump. The output shaft portion is rotatably provided via a bearing at a position eccentrically located with respect to the input shaft portion. The rotation of the input shaft portion is transferred through a first power transmission mechanism, including an inner gear, to the output shaft portion to cause the output shaft portion to carry out an eccentric rotational movement. The input shaft portion and the output shaft portion are arranged inside a pitch circle of the inner gear.
    Type: Grant
    Filed: January 29, 2008
    Date of Patent: May 28, 2013
    Assignee: Heishin Sobi Kabushiki Kaisha
    Inventors: Teruaki Akamatsu, Mikio Yamashita, Nobuhisa Suhara
  • Publication number: 20130048451
    Abstract: A shock absorber includes a piston partitioning an inside of a cylinder into a rod-side chamber and a bottom-side chamber, a piston rod having a first end connected to the piston and a second end extending to an outside of the cylinder, a housing provided on the first end side of the piston rod, a free piston slidably inserted into the housing, a rod passage allowing the rod-side chamber to communicate with a pressure chamber within the housing, and damping valves provided in passages allowing the rod-side chamber to communicate with the bottom-side chamber. The free piston is provided with a shutter member that adjusts the opening area of a pressure chamber opening of the rod passage according to a movement of the free piston.
    Type: Application
    Filed: August 30, 2012
    Publication date: February 28, 2013
    Inventor: MIKIO YAMASHITA
  • Publication number: 20120248670
    Abstract: A shock absorber includes first passages configured to communicate two chambers to flow a working fluid therebetween by movement of a piston, and a second passage configured to communicate with one chamber of the two chambers. The first passages have damping valves configured to suppress a flow of the working fluid generated by movement of the piston to generate a damping force. The second passage has a variable orifice having an area adjusted by an elastic member when a piston rod moves in an extension direction, a pressure chamber installed in series with the variable orifice, and a free piston configured to vary a volume of the pressure chamber by movement of the piston.
    Type: Application
    Filed: March 19, 2012
    Publication date: October 4, 2012
    Inventors: Mikio Yamashita, Fumiyuki Yamaoka, Masaru Kouyama, Atsushi Maeda
  • Publication number: 20120160624
    Abstract: A frequency-dependent mechanism provided at the lower end of a piston rod includes a tubular housing displaceable in an inner tube, together with the piston rod as one unit, and further includes a free piston and O-rings. A shutter of a passage area varying mechanism is provided with an axially extending inner hole, orifices, and oil grooves. The opening area between oil holes 3C and the orifices 33B is changed according to the rotational position of the shutter. The opening area between oil holes 3D and 3E and the oil grooves 33C and 33D and the opening area between oil holes 3F and 3G and the oil grooves 33E and 33F are also variably adjusted according to the rotational position of the shutter.
    Type: Application
    Filed: December 28, 2011
    Publication date: June 28, 2012
    Inventors: Yohei KATAYAMA, Takao Nakadate, Kenji Noda, Mikio Yamashita, Fumiyuki Yamaoka
  • Publication number: 20120160620
    Abstract: Oil grooves of a shutter and oil holes of a stepped rod constitute first orifices as variable orifices whose opening areas are variable according to the rotational position of the shutter. The oil grooves of the shutter and oil holes of the stepped rod constitute third orifices as variable orifices. Cut portions of inner disk valves constitute second orifices. The opening areas of the variable orifices are changed by rotating the shutter, thereby controlling damping force characteristics in a low piston speed region and the relief pressures of pressure control valves independently of each other, and thus increasing the degree of freedom for adjusting the damping force characteristics.
    Type: Application
    Filed: December 28, 2011
    Publication date: June 28, 2012
    Inventors: Mikio YAMASHITA, Fumiyuki YAMAOKA
  • Publication number: 20110214953
    Abstract: A shock absorber has an inclined surface that is inclined to a moving direction of the free piston in at least one of a free piston contact surface of a free piston with which an elastic body is in contact and a housing contact surface of a housing with which the elastic body is in contact. A shortest distance between the free piston contact surface and the housing contact surface is changed by movement of the free piston.
    Type: Application
    Filed: February 28, 2011
    Publication date: September 8, 2011
    Inventors: Atsushi Maeda, Masaru Kouyama, Mikio Yamashita, Fumiyuki Yamaoka