Patents by Inventor Takao Nakadate

Takao Nakadate 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: 10941830
    Abstract: In a shock absorber, an extension-side check valve permitting a flow of hydraulic fluid directed from a common passage to a compression-side passage side, and a compression-side orifice establishing communication between the compression-side passage and a compression-side back-pressure chamber are provided in an extension-side discharge passage. A compression-side check valve permitting a flow of hydraulic fluid directed from the common passage to an extension-side passage side, and an extension-side orifice establishing communication between the extension-side passage and an extension-side back-pressure chamber are provided in a compression-side discharge passage. A pilot valve includes a valve body slidably inserted in the common passage, and a valve spring biasing the valve body in a valve-opening direction.
    Type: Grant
    Filed: January 16, 2018
    Date of Patent: March 9, 2021
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Kosuke Kadokura, Takao Nakadate, Shunsuke Mori, Osamu Yuno
  • Publication number: 20200191229
    Abstract: Provided is a shock absorber that is so designed that fail-down is prevented, which is caused when solenoid thrust is relatively small. The shock absorber comprises a chamber disposed on one side of a valve element and communicating with a cylinder's one side chamber and a cylinder's other side chamber, a first communication passage allowing the chamber and the cylinder's one side chamber to communicate with each other, and a second communication passage allowing the chamber and the cylinder's other side chamber to communicate with each other. The first communication passage includes a first orifice, and the second communication passage includes a second orifice.
    Type: Application
    Filed: September 4, 2018
    Publication date: June 18, 2020
    Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Shunsuke MORI, Takao NAKADATE, Yu ISHIMARU, Osamu YUNO
  • Publication number: 20200166097
    Abstract: The present invention provides a shock absorber capable of improving responsiveness during an extension stroke without leading to an increase in an axial length. A shock absorber includes a chamber provided on a one-side end of a pilot valve and disposed in communication with a cylinder upper chamber, a communication passage configured to establish communication between the chamber and a cylinder lower chamber via a compression-side passage, and a check valve configured to permit hydraulic fluid in the communication passage to flow into the cylinder lower chamber during an extension stroke.
    Type: Application
    Filed: July 24, 2018
    Publication date: May 28, 2020
    Inventors: Kosuke KADOKURA, Yohei KATAYAMA, Takao NAKADATE, Osamu YUNO, Shunsuke MORI
  • Publication number: 20200032872
    Abstract: In a shock absorber, an extension-side check valve permitting a flow of hydraulic fluid directed from a common passage to a compression-side passage side, and a compression-side orifice establishing communication between the compression-side passage and a compression-side back-pressure chamber are provided in an extension-side discharge passage. A compression-side check valve permitting a flow of hydraulic fluid directed from the common passage to an extension-side passage side, and an extension-side orifice establishing communication between the extension-side passage and an extension-side back-pressure chamber are provided in a compression-side discharge passage. A pilot valve includes a valve body slidably inserted in the common passage, and a valve spring biasing the valve body in a valve-opening direction.
    Type: Application
    Filed: January 16, 2018
    Publication date: January 30, 2020
    Inventors: Kosuke KADOKURA, Takao NAKADATE, Shunsuke MORI, Osamu YUNO
  • Patent number: 8794400
    Abstract: A damping force adjustable hydraulic shock absorber, in which response delay of a pressure control valve and self-excited vibration of a valve body can be prevented. A damping force is generated by controlling an oil flow between an annular oil passage (21) and a reservoir (4) generated by sliding movement of a piston in a cylinder with use of a back-pressure type main valve (27) and a pressure control valve (28). The damping force is directly generated by the pressure control valve, and valve-opening pressure of the main valve is adjusted by adjusting an inner pressure of a back-pressure chamber. In the pressure control valve, a valve spring is disposed between a valve body and a plunger. A mass of the valve body is sufficiently less than that of the plunger, and a spring stiffness of the valve spring is higher than that of a plunger spring.
    Type: Grant
    Filed: March 31, 2009
    Date of Patent: August 5, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Takao Nakadate, Takashi Nezu, Yohei Katayama, Shigeo Katayama, Hiroyuki Yabe
  • 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: 8376099
    Abstract: A volume compensation accumulator apparatus connected to a conduit connecting hydraulic cylinders in a suspension system. The volume compensation accumulator apparatus includes an arrangement of the two orifice plates in series in a spaced-apart relation, which eliminates the necessity of reducing the diameters of the orifices while providing the same orifice characteristic as that of an orifice having a smaller diameter, thereby making the boring process of the orifice easy, and reducing clogging of the orifices with foreign objects.
    Type: Grant
    Filed: March 24, 2010
    Date of Patent: February 19, 2013
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Shunsuke Mori, Takao Nakadate, Kenichi Nakamura
  • 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
  • Patent number: 7997588
    Abstract: There is provided with a cylinder apparatus comprising: a cylinder; a piston; a piston rod, one end of which is connected to the piston and the other end of which is extended outside; an external cylinder provided at an outer periphery of the cylinder so as to form a reservoir in which to seal the hydraulic liquid and gas therebetween; a base valve dividing the second chamber and the reservoir; a first check valve provided with the piston so as to allow flow of the hydraulic liquid only from the second chamber side to the first chamber side; a second check valve provided with the base valve so as to allow flow of the hydraulic liquid only from the reservoir side to the second chamber side; a flow passage connecting the first chamber with the reservoir; and an opening and closing valve opening and closing the flow passage.
    Type: Grant
    Filed: March 20, 2009
    Date of Patent: August 16, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Ohnuma, Takao Nakadate
  • Publication number: 20100300821
    Abstract: The present invention enables easy formation of an extremely small orifice in a volume compensation accumulator apparatus connected to a conduit connecting hydraulic cylinders in a suspension system. The volume compensation accumulator apparatus comprises an arrangement of the two orifice plates in series in a spaced-apart relation, which eliminates the necessity of reducing the diameters of the orifices while providing the same orifice characteristic as that of an orifice having a smaller diameter, thereby making the boring process of the orifice easy, and reducing clogging of the orifices with foreign objects.
    Type: Application
    Filed: March 24, 2010
    Publication date: December 2, 2010
    Inventors: Shunsuke Mori, Takao Nakadate, Kenichi Nakamura
  • Patent number: 7694785
    Abstract: A controllable damping force hydraulic shock absorber including a pilot type damping valve having a back-pressure chamber for each of an extension stroke and a compression stroke. A piston connected to a piston rod is fitted into a sealed cylinder in which a hydraulic fluid is contained. During an extension stroke of the piston rod, the hydraulic fluid in an upper cylinder chamber flows to a lower cylinder chamber through an extension-side hydraulic fluid passage, an extension-side orifice hydraulic fluid passage, an extension-side back-pressure chamber, an axial hydraulic fluid passage, a radial hydraulic fluid passage, a compression-side back-pressure chamber, an extension-side check valve and a compression-side hydraulic fluid passage.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: April 13, 2010
    Assignee: Hitachi, Ltd.
    Inventor: Takao Nakadate
  • Publication number: 20090267311
    Abstract: There is provided with a cylinder apparatus comprising: a cylinder; a piston; a piston rod, one end of which is connected to the piston and the other end of which is extended outside; an external cylinder provided at an outer periphery of the cylinder so as to form a reservoir in which to seal the hydraulic liquid and gas therebetween; a base valve dividing the second chamber and the reservoir; a first check valve provided with the piston so as to allow flow of the hydraulic liquid only from the second chamber side to the first chamber side; a second check valve provided with the base valve so as to allow flow of the hydraulic liquid only from the reservoir side to the second chamber side; a flow passage connecting the first chamber with the reservoir; and an opening and closing valve opening and closing the flow passage.
    Type: Application
    Filed: March 20, 2009
    Publication date: October 29, 2009
    Applicant: Hitachi, Ltd.
    Inventors: Takashi Ohnuma, Takao Nakadate
  • Publication number: 20090242339
    Abstract: An object of the present invention is to provide a damping force adjustable hydraulic shock absorber, in which response delay of a pressure control valve and self-excited vibration of a valve body can be prevented. A damping force is generated by controlling an oil flow between an annular oil passage 21 and a reservoir 4 generated by a sliding movement of a piston in a cylinder with use of a back-pressure type main valve 27 and a pressure control valve 28. The damping force is directly generated by the pressure control valve 28, and a valve-opening pressure of the main valve 27 is adjusted by adjusting an inner pressure of a back-pressure chamber 53. In the pressure control valve 28, a valve spring 57 is disposed between a valve body 56 and a plunger 34. A mass of the valve body 56 is sufficiently less than that of a plunger 34, and a spring stiffness of the valve spring 57 is higher than that of a plunger spring 36.
    Type: Application
    Filed: March 31, 2009
    Publication date: October 1, 2009
    Inventors: Takao Nakadate, Takashi Nezu, Yohei Katayama, Shigeo Katayama, Hiroyuki Yabe
  • Patent number: 7458448
    Abstract: A hydraulic shock absorber in which the flow of hydraulic fluid induced in each of extension and compression hydraulic fluid passages, by sliding movement of a piston, is controlled by a main disk valve to generate damping force. The valve opening pressure of the main disk valve is adjusted by the pressure in a back-pressure chamber. In a low piston speed region, the main disk valve closes a back-pressure chamber inlet passage. Therefore, the pressure in the backpressure chamber will not rise, and sufficiently small damping force is obtained. When the main disk valve opens, the backpressure chamber inlet passage opens simultaneously. Consequently, the pressure in the backpressure chamber rises, and the damping force increases.
    Type: Grant
    Filed: May 23, 2005
    Date of Patent: December 2, 2008
    Assignees: Hitachi, Ltd., Nissan Motor Co., Ltd.
    Inventors: Hajime Katou, Hikaru Nakajima, Takao Nakadate
  • Publication number: 20060225976
    Abstract: The present invention provides a controllable damping force hydraulic shock absorber comprising a pilot type damping valve having a back-pressure chamber for each of an extension stroke and a compression stroke, which has a simple structure. A piston connected to a piston rod is fitted into a sealed cylinder in which a hydraulic fluid is contained. During an extension stroke of the piston rod, the hydraulic fluid in an upper cylinder chamber flows to a lower cylinder chamber through an extension-side hydraulic fluid passage, an extension-side orifice hydraulic fluid passage, an extension-side back-pressure chamber, an axial hydraulic fluid passage, a radial hydraulic fluid passage, a compression-side back-pressure chamber, an extension-side check valve and a compression-side hydraulic fluid passage.
    Type: Application
    Filed: March 27, 2006
    Publication date: October 12, 2006
    Inventor: Takao Nakadate
  • Publication number: 20050263363
    Abstract: In the disclosed hydraulic shock absorber, the flow of hydraulic fluid induced in each of extension and compression hydraulic fluid passages by sliding movement of a piston is controlled by a main disk valve to generate damping force. The valve opening pressure of the main disk valve is adjusted by the pressure in a back-pressure chamber. In a low piston speed region, the main disk valve closes a back-pressure chamber inlet passage. Therefore, the pressure in the back-pressure chamber will not rise, and sufficiently small damping force is obtained. When the main disk valve opens, the back-pressure chamber inlet passage opens simultaneously. Consequently, the pressure in the back-pressure chamber rises, and the damping force increases.
    Type: Application
    Filed: May 23, 2005
    Publication date: December 1, 2005
    Inventors: Hajime Katou, Hikaru Nakajima, Takao Nakadate
  • Patent number: 6860370
    Abstract: A piston having a piston rod connected thereto is slidably fitted in a cylinder in which a hydraulic fluid is sealably contained. Extension-stroke and compression-stroke pilot type damping force control mechanisms are provided in the piston. Check valves are provided at inlet openings of back-pressure chambers (pilot chambers). Relief valves provided in the pilot chambers include orifice passages. When the direction of stroke of the piston rod is reversed, the pressures in the back-pressure chambers are maintained due to the check valves, and the back-pressure chambers are pressurized to a satisfactory level through the orifice passages.
    Type: Grant
    Filed: November 27, 2002
    Date of Patent: March 1, 2005
    Assignee: Tokico Ltd.
    Inventor: Takao Nakadate
  • Patent number: 6782980
    Abstract: A piston having a piston rod connected thereto is slidably fitted in a cylinder in which a hydraulic fluid is sealably contained. Extension-stroke and compression-stroke pilot type damping force control mechanisms are provided in the piston. A pilot control valve of the extension-stroke pilot type damping force control mechanism is formed by a pressure control valve having a valve seat, a valve body and a pressure-receiving portion. A pilot control valve of the compression-stroke pilot type damping force control mechanism is formed by a flow rate control valve having a spool. A slider having the valve body of the pressure control valve and the spool of the flow rate control valve is operated by a proportional solenoid, to thereby control a damping force for an extension stroke and a damping force for a compression stroke.
    Type: Grant
    Filed: November 27, 2002
    Date of Patent: August 31, 2004
    Assignee: Tokico Ltd.
    Inventor: Takao Nakadate
  • Publication number: 20030132073
    Abstract: A piston having a piston rod connected thereto is slidably fitted in a cylinder in which a hydraulic fluid is sealably contained. Extension-stroke and compression-stroke pilot type damping force control mechanisms are provided in the piston. A pilot control valve of the extension-stroke pilot type damping force control mechanism is formed by a pressure control valve having a valve seat, a valve body and a pressure-receiving portion. A pilot control valve of the compression-stroke pilot type damping force control mechanism is formed by a flow rate control valve having a spool. A slider having the valve body of the pressure control valve and the spool of the flow rate control valve is operated by a proportional solenoid, to thereby control a damping force for an extension stroke and a damping force for a compression stroke.
    Type: Application
    Filed: November 27, 2002
    Publication date: July 17, 2003
    Inventor: Takao Nakadate
  • Publication number: 20030098209
    Abstract: A piston having a piston rod connected thereto is slidably fitted in a cylinder in which a hydraulic fluid is sealably contained. Extension-stroke and compression-stroke pilot type damping force control mechanisms are provided in the piston. Check valves are provided at inlet openings of back-pressure chambers (pilot chambers). Relief valves provided in the pilot chambers include orifice passages. When the direction of stroke of the piston rod is reversed, the pressures in the back-pressure chambers are maintained due to the check valves, and the back-pressure chambers are pressurized to a satisfactory level through the orifice passages.
    Type: Application
    Filed: November 27, 2002
    Publication date: May 29, 2003
    Inventor: Takao Nakadate