Patents by Inventor Takashi Nezu

Takashi Nezu 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: 10106009
    Abstract: A suspension control apparatus for a vehicle including a damping-force adjustable shock absorber interposed between a vehicle body and a wheel of a vehicle, and a controller for variably controlling damping-force characteristics of the damping-force adjustable shock absorber between hard and soft. The controller is configured to switch the damping-force characteristics to a soft side when a direction of a stroke of the damping-force adjustable shock absorber is reversed between an extension stroke and a contraction stroke.
    Type: Grant
    Filed: November 29, 2010
    Date of Patent: October 23, 2018
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Ryusuke Hirao, Takashi Nezu, Nobuyuki Ichimaru, Takahide Kobayashi
  • Patent number: 9046145
    Abstract: A shock absorber in which a flow of hydraulic oil caused by sliding movement of a piston in a cylinder is controlled by a pilot type main valve and a pilot valve to generate damping force. The valve-opening operation of the main valve is controlled by adjusting the pressure in a pilot chamber with the pilot valve. A valve block and a solenoid block are connected together into one unit and inserted into a casing before being secured with a nut. At this time, an actuating rod of the solenoid block is engaged with a pilot valve member retained by a pilot spring and a fail-safe spring in a cylindrical portion of a pilot body of the valve block.
    Type: Grant
    Filed: May 24, 2012
    Date of Patent: June 2, 2015
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Hiroshi Murakami, Osamu Yuno, Tomohiko Fujioka, Takashi Nezu, Shunsuke Mori
  • Patent number: 8800729
    Abstract: During either of the extension and compression strokes, hydraulic liquid flows from a cylinder upper chamber into a reservoir through an annular passage and a damping force control mechanism, and a damping force is generated by the damping force control mechanism. The check valve is provided with a sub-check valve in parallel thereto, which opens in a very low piston speed region to allow the hydraulic liquid to flow through an orifice passage. These check valves are opened successively as the piston speed increases, thereby generating a sufficiently small damping force in the very low piston speed region during the compression stroke of the piston rod, and obtaining a moderate damping force when the piston speed increases.
    Type: Grant
    Filed: March 19, 2012
    Date of Patent: August 12, 2014
    Assignee: Hitachi Automotive Systems, Ltd.
    Inventors: Hiroyuki Yabe, Yohei Katayama, Takashi Nezu
  • 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: 8544619
    Abstract: A fluid pressure shock absorber in which valve opening of the main valve is controlled by an inner pressure of a backpressure chamber. A first piston (3) and a second piston (4) coupled to a piston rod (10) are fitted in a cylinder (2) such that a piston chamber (2C) is defined between the first and second pistons. An extension-side main valve (18) and a compression-side main valve (23) are provided in the piston chamber (2C). Valve opening of the main valves is controlled by an extension-side backpressure chamber (19) and a compression-side backpressure chamber (24). A compression-side check valve (13) and an extension-side check valve (16) are provided at the first piston (3) and the second piston (4). During an extension stroke of the piston rod (10), the compression-side check valve (13) is closed, whereby action of a pressure of a cylinder upper chamber (2A) on the compression-side main valve (23) is prevented.
    Type: Grant
    Filed: March 27, 2008
    Date of Patent: October 1, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Yamaguchi, Yohei Katayama, Hiroyuki Hayama, Takashi Nezu
  • Publication number: 20120305348
    Abstract: Provided is a suspension apparatus capable of preventing excessive increase in damping force due to a sudden input from the road surface when the damping force is adjusted to a minimum value during running. A damping force control type hydraulic shock absorber (1) includes a damping force adjusting valve (25) which adjusts a damping force by a current supplied to a pressure control valve for controlling a pilot pressure. A control device (ECU) outputs a minimum control current I=0.5 A to cause the damping force control type hydraulic shock absorber (1) to generate a minimum damping force. When the minimum control current is supplied, the pressure control valve of the damping force adjusting valve (25) is always opened. Thus, an increase of the damping force caused by a rapid increase of the pilot pressure due to the sudden input from the road surface is suppressed.
    Type: Application
    Filed: February 12, 2010
    Publication date: December 6, 2012
    Inventors: Yohei Katayama, Takashi Nezu
  • Publication number: 20120305349
    Abstract: A shock absorber in which a flow of hydraulic oil caused by sliding movement of a piston in a cylinder is controlled by a pilot type main valve and a pilot valve to generate damping force. The valve-opening operation of the main valve is controlled by adjusting the pressure in a pilot chamber with the pilot valve. A valve block and a solenoid block are connected together into one unit and inserted into a casing before being secured with a nut. At this time, an actuating rod of the solenoid block is engaged with a pilot valve member retained by a pilot spring and a fail-safe spring in a cylindrical portion of a pilot body of the valve block.
    Type: Application
    Filed: May 24, 2012
    Publication date: December 6, 2012
    Inventors: Hiroshi MURAKAMI, Osamu YUNO, Tomohiko FUJIOKA, Takashi NEZU, Shunsuke MORI
  • Publication number: 20120247889
    Abstract: During either of the extension and compression strokes, hydraulic liquid flows from a cylinder upper chamber into a reservoir through an annular passage and a damping force control mechanism, and a damping force is generated by the damping force control mechanism. The check valve is provided with a sub-check valve in parallel thereto, which opens in a very low piston speed region to allow the hydraulic liquid to flow through an orifice passage. These check valves are opened successively as the piston speed increases, thereby generating a sufficiently small damping force in the very low piston speed region during the compression stroke of the piston rod, and obtaining a moderate damping force when the piston speed increases.
    Type: Application
    Filed: March 19, 2012
    Publication date: October 4, 2012
    Inventors: Hiroyuki Yabe, Yohei Katayama, Takashi Nezu
  • Publication number: 20110127127
    Abstract: Provided is a suspension control apparatus for a vehicle comprising a damping-force adjustable shock absorber interposed between a vehicle body and a wheel of a vehicle, and a controller for variably controlling damping-force characteristics of the damping-force adjustable shock absorber between hard and soft, wherein the controller is configured to switch the damping-force characteristics to a soft side when a direction of a stroke of the damping-force adjustable shock absorber is reversed between an extension stroke and a contraction stroke.
    Type: Application
    Filed: November 29, 2010
    Publication date: June 2, 2011
    Inventors: Ryusuke HIRAO, Takashi Nezu, Nobuyuki Ichimaru, Takahide Kobayashi
  • Publication number: 20110024245
    Abstract: A shock absorber comprising: a cylinder; a piston partitioning the cylinder into two chambers; a piston rod; a by-pass passage passing through the chambers; and a damping-force adjusting mechanism adjusting a passage area of the by-pass passage, wherein the adjusting mechanism includes: a shutter guide; a shutter movably guided by the shutter guide; and an elastic member elastically retaining the shutter at an initial position, an adjustable passage adjusting the passage area of the by-pass passage as that opening is varied by shift of the shutter is formed, shift of the shutter is not influenced by pressure difference between the chambers, and when the shutter is at the initial position, the adjustable passage is opened with a predetermined degree, and the shutter moves to close the adjustable passage by fluid force that generates by flow of the working fluid of the adjustable passage against elastic force of the elastic member.
    Type: Application
    Filed: July 26, 2010
    Publication date: February 3, 2011
    Applicant: Hitachi Automotive Systems, Ltd.
    Inventors: Takashi Nezu, Atsufumi Ishimoto, Shigeo Katayama
  • Patent number: 7757826
    Abstract: A first piston and a second piston coupled to a piston rod are fitted in a cylinder, and an intermediate chamber is formed between the first and second pistons. A compression-side check valve and an extension-side check valve are provided at the first piston and the second piston. An extension-side main valve and a compression-side main valve are disposed in the intermediate chamber. A downstream side of a damping force adjusting valve is connected to the intermediate chamber. Inner pressures of an extension-side backpressure chamber and a compression-side backpressure chamber are adjusted by the damping force adjusting valve, whereby valve opening of the extension-side and compression-side main valves is controlled. Hydraulic fluid of the downstream side of the damping force adjusting valve is first sent into the intermediate chamber, and then is sent to a cylinder upper chamber or a cylinder lower chamber.
    Type: Grant
    Filed: March 21, 2008
    Date of Patent: July 20, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Hayama, Yohei Katayama, Takashi Nezu
  • Publication number: 20090272611
    Abstract: A first piston and a second piston coupled to a piston rod are fitted in a cylinder, and an intermediate chamber is formed between the first and second pistons. A compression-side check valve and an extension-side check valve are provided at the first piston and the second piston. An extension-side main valve and a compression-side main valve are disposed in the intermediate chamber. A downstream side of a damping force adjusting valve is connected to the intermediate chamber. Inner pressures of an extension-side backpressure chamber and a compression-side backpressure chamber are adjusted by the damping force adjusting valve, whereby valve opening of the extension-side and compression-side main valves is controlled. Hydraulic fluid of the downstream side of the damping force adjusting valve is first sent into the intermediate chamber, and then is sent to a cylinder upper chamber or a cylinder lower chamber.
    Type: Application
    Filed: March 21, 2008
    Publication date: November 5, 2009
    Inventors: Hiroyuki Hayama, Yohei Katayama, Takashi Nezu
  • 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
  • Publication number: 20090000891
    Abstract: A piston connected with a piston rod is slidably fitted in a cylinder having a hydraulic fluid sealed therein. An extension-side main disk valve generates a damping force in a high piston speed region against the flow of hydraulic fluid in an extension-side passage. A sub-passage bypasses the extension-side main disk valve, and an extension-side sub disk valve generates a damping force in an intermediate piston speed region. A compression-side main disk valve generates a damping force in the high piston speed region against the flow of hydraulic fluid in a compression-side passage. A sub-passage bypasses the compression-side main disk valve, and a compression-side sub disk valve generates a damping force in the intermediate piston speed region. Damping force characteristics in the intermediate and high piston speed regions can be set according to the valve-opening characteristics of these disk valves. Therefore, it is possible to increase the degree of freedom for setting damping force characteristics.
    Type: Application
    Filed: June 26, 2008
    Publication date: January 1, 2009
    Inventors: Masaru Kouyama, Hiroshi Murakami, Takashi Nezu
  • Publication number: 20080257668
    Abstract: An object of the present invention is to generate a stable damping force and enhance durability of a main valve in a hydraulic shock absorber in which valve opening of the main valve is controlled by an inner pressure of a backpressure chamber. A first piston 3 and a second piston 4 coupled to a piston rod 10 are fitted in a cylinder 2 such that a piston chamber 2C is defined between the first and second pistons 3, 4. An extension-side main valve 18 and a compression-side main valve 23 are provided in the piston chamber 2C. Valve opening of the main valves is controlled by an extension-side backpressure chamber 19 and a compression-side backpressure chamber 24. A compression-side check valve 13 and an extension-side check valve 16 are provided at the first piston 3 and the second piston 4. During an extension stroke of the piston rod 10, the compression-side check valve 13 is closed, whereby action of a pressure of a cylinder upper chamber 2A on the compression-side main valve 23 is prevented.
    Type: Application
    Filed: March 27, 2008
    Publication date: October 23, 2008
    Inventors: Hiroyuki Yamaguchi, Yohei Katayama, Hiroyuki Hayama, Takashi Nezu
  • Patent number: 6817454
    Abstract: A piston connected to a piston rod is slidably fitted in a cylinder having a hydraulic fluid sealed therein. First and second poppet valves having different valve opening characteristics are provided in first and second extension main passages, respectively. A pilot control valve is provided in a sub-passage. The control pressure of the pilot control valve is adjusted by a proportional solenoid, thereby controlling damping force. At the same time, the pressure at the upstream side of the pilot control valve is introduced into back-pressure chambers to adjust the valve opening pressures of the first and second poppet valves. Because the first and second poppet valves are sequentially opened or closed, damping force can be controlled stepwisely, and ideal damping force characteristics can be obtained.
    Type: Grant
    Filed: December 11, 2002
    Date of Patent: November 16, 2004
    Assignee: Tokico Ltd.
    Inventors: Takashi Nezu, Yohei Katayama
  • Patent number: 6729446
    Abstract: A damping force control type hydraulic shock absorber includes a plunger having a small-diameter main body portion slidably guided by a first fixed core made of a magnetic material. The plunger has a large-diameter attracted portion at an end thereof closer to a second fixed core. The diameter (D2) of the attracted portion is set larger than the diameter (D1) of the main body portion (D2>D1), thereby increasing the area of the mutually opposing surfaces of the attracted portion and the second fixed core. Accordingly, attraction force acting on the attracted portion can be increased without reducing the magnetic flux density at the main body portion.
    Type: Grant
    Filed: April 25, 2001
    Date of Patent: May 4, 2004
    Assignee: Tokico, Ltd.
    Inventors: Hiroshi Sakai, Takashi Nezu
  • Publication number: 20030106753
    Abstract: A piston connected with a piston rod is slidably fitted in a cylinder having a hydraulic fluid sealed therein. First and second poppet valves having different valve opening characteristics are provided in first and second extension main passages, respectively. A pilot control valve is provided in a sub-passage. The control pressure of the pilot control valve is adjusted by a proportional solenoid, thereby controlling damping force. At the same time, the pressure at the upstream side of the pilot control valve is introduced into back-pressure chambers to adjust the valve opening pressures of the first and second poppet valves. Because the first and second poppet valves are sequentially opened or closed, damping force can be controlled stepwisely, and ideal damping force characteristics can be obtained.
    Type: Application
    Filed: December 11, 2002
    Publication date: June 12, 2003
    Inventors: Takashi Nezu, Yohei Katayama
  • Patent number: 6474454
    Abstract: A pilot chamber is formed at the back of a disk valve for each of the fluid flow systems for the extension and compression strokes. Damping force in a low piston speed region is controlled with a pressure control valve. The valve opening pressure of the disk valve is controlled by varying a pilot pressure introduced into the pilot chamber from a cylinder's hydraulic fluid chamber through a cut portion in a piston bolt and an orifice groove formed in a fixed member supporting the disk valve, thereby controlling damping force in a high piston speed region. A sharp pressure change occurring when the stroke direction of a piston rod changes is attenuated by the restricting action of the orifice groove so as not to be readily transmittable to the pilot chamber.
    Type: Grant
    Filed: May 30, 2001
    Date of Patent: November 5, 2002
    Assignee: Tokico Ltd.
    Inventors: Takuya Matsumoto, Takashi Nezu
  • Publication number: 20020121416
    Abstract: A free piston defines a gas chamber in a cylinder, an interior of which is divided into a rod-side chamber and a bottom-side chamber by a piston. An accumulator having a gas chamber is connected to the rod-side chamber by a first oil line, midway of which is provided a damping-force generating unit. Also, the bottom-side chamber and the first oil line are communicated to each other by a communication line, midway of which is provided a spring-constant switchover valve for communication and shut-off of the communication line. Accordingly, when the spring-constant switchover valve puts the communication line in communication, the two gas chambers are compressed to make a spring constant small, thereby making comfort in a vehicle favorable. Meanwhile, the spring-constant switchover valve shuts off the communication line, only one of the gas chambers is compressed to make the spring constant large, thereby limiting a contracting displacement of a piston rod and suppressing rolling of the vehicle.
    Type: Application
    Filed: February 15, 2002
    Publication date: September 5, 2002
    Inventors: Yohei Katayama, Takashi Nezu, Kenichi Nakamura