Patents by Inventor Fumiaki Kawahata

Fumiaki Kawahata 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: 6957870
    Abstract: A braking pressure control apparatus including a first pressure source including a power-operated pressurizing device, a second pressure source operable by a manually operable brake operating member to pressurize a fluid to a pressure higher than a level corresponding to the operating force of the brake operating member, a switching device for selectively placing the braking system in a first state in which a brake cylinder is operated with the fluid pressurized by the first pressure source and a second state in which the brake cylinder is operated with the fluid pressurized by the second pressure source, and a change restricting device operable upon a switching between the first and second states, to restrict a change of the operating state of the brake operating member and a change of the brake cylinder pressure, which change take place due to the switching, or a switching control device for controlling the switching device on the basis of the running condition of a vehicle whose wheel is braked by the brak
    Type: Grant
    Filed: December 15, 2000
    Date of Patent: October 25, 2005
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Kazunori Kagawa, Kimihiro Matsuki, Tetsuya Miyazaki, Fumiaki Kawahata, Akihiro Otomo, Eiji Nakamura
  • Patent number: 6450591
    Abstract: In a hydraulic brake pressure control system, a master cylinder generates a brake fluid pressure proportional to a brake pedal pressure and a high-pressure supply device generates an increased brake fluid pressure. A hydraulic circuit having a wheel cylinder device is capable of performing a master cylinder control to control a wheel cylinder pressure by using the pressure generated by the master cylinder, and capable of performing a brake-by-wire control to control the wheel cylinder pressure by using the pressure generated by the high-pressure supply device. The hydraulic brake pressure control system includes a master cut valve device which controls a flow of brake fluid from the master cylinder into the wheel cylinder device. A wheel cylinder sensor device outputs a signal indicative of the brake fluid pressure in the wheel cylinder device.
    Type: Grant
    Filed: August 3, 1998
    Date of Patent: September 17, 2002
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Fumiaki Kawahata, Masayasu Ohkubo
  • Patent number: 6425644
    Abstract: A braking pressure control apparatus for a hydraulically operated brake, including a first hydraulic system having a first hydraulic pressure source power-operated to pressurize a working fluid and capable of controlling the fluid pressure, for operating the brake, a second hydraulic system having a second hydraulic pressure source operable by an operating force acting on a manually operable brake operating member, to pressurize the working fluid to a pressure higher than a level corresponding to the operating force, for operating the brake, a switching device operable to selectively establish a first state in which the brake is operated with the pressurized fluid delivered from the first hydraulic pressure source, and a second state in which the brake is operated with the pressurized fluid delivered from the second hydraulic pressure source, and a diagnosing device operable to diagnose the second hydraulic system on the basis of the fluid pressure in the second hydraulic system.
    Type: Grant
    Filed: November 29, 2000
    Date of Patent: July 30, 2002
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Fumiaki Kawahata, Tetsuya Miyazaki, Hirohiko Morikawa, Akihiro Otomo
  • Patent number: 6354672
    Abstract: A braking system including a brake cylinder, a first hydraulic pressure source having a first pump device for pressurizing a working fluid, a second hydraulic pressure source operable in response to an operation of a brake operating member, to pressurize the fluid to a pressure higher than a value corresponding to an operating force of the brake operating member, and a brake-cylinder-pressure control device operable when the brake cylinder is disconnected from the second hydraulic pressure source, to control the pressure of the fluid pressurized by the first hydraulic pressure source, such that the fluid pressure in the brake cylinder is controlled to a value determined on the basis of the operating force, and wherein an emergency communication device is operated when at least one of the brake-cylinder-pressure control device and the first pump device fails to normally function, to hold the brake cylinder in communication with the second hydraulic pressure source.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: March 12, 2002
    Assignees: Toyota Jidosha Kabushiki Kaisha, Aisin Seiki Kabushiki Kaisha
    Inventors: Eiji Nakamura, Akihiro Otomo, Fumiaki Kawahata, Tetsuya Miyazaki, Hiroshi Toda
  • Publication number: 20010006308
    Abstract: A braking pressure control apparatus for a hydraulically operated brake, including a first hydraulic system having a first hydraulic pressure source power-operated to pressurize a working fluid and capable of controlling the fluid pressure, for operating the brake, a second hydraulic system having a second hydraulic pressure source operable by an operating force acting on a manually operable brake operating member, to pressurize the working fluid to a pressure higher than a level corresponding to the operating force, for operating the brake, a switching device operable to selectively establish a first state in which the brake is operated with the pressurized fluid delivered from the first hydraulic pressure source, and a second state in which the brake is operated with the pressurized fluid delivered from the second hydraulic pressure source, and a diagnosing device operable to diagnose the second hydraulic system on the basis of the fluid pressure in the second hydraulic system.
    Type: Application
    Filed: November 29, 2000
    Publication date: July 5, 2001
    Applicant: Toyota Jidosha Kabushiki Kaisha
    Inventors: Fumiaki Kawahata, Tetsuya Miyazaki, Hirohiko Morikawa, Akihiro Otomo
  • Publication number: 20010006306
    Abstract: A braking pressure control apparatus including a first pressure source including a power-operated pressurizing device, a second pressure source operable by a manually operable brake operating member to pressurize a fluid to a pressure higher than a level corresponding to the operating force of the brake operating member, a switching device for selectively placing the braking system in a first state in which a brake cylinder is operated with the fluid pressurized by the first pressure source and a second state in which the brake cylinder is operated with the fluid pressurized by the second pressure source, and a change restricting device operable upon a switching between the first and second states, to restrict a change of the operating state of the brake operating member and a change of the brake cylinder pressure, which change take place due to the switching, or a switching control device for controlling the switching device on the basis of the running condition of a vehicle whose wheel is braked by the brak
    Type: Application
    Filed: January 8, 2001
    Publication date: July 5, 2001
    Applicant: Toyota Jidosha Kabushiki Kaisha
    Inventors: Kazunori Kagawa, Kimihiro Matsuki, Tetsuya Miyazaki, Fumiaki Kawahata, Akihiro Otomo, Eiji Nakamura
  • Patent number: 6164734
    Abstract: Vehicle hydraulic braking system including a hydraulic pressure source for pressurizing a fluid according to an operation of a brake operating member, so that the pressurized fluid is supplied to at least one wheel brake cylinder for braking at least wheel of the vehicle, a pressure control valve device for regulating the pressure of the fluid to be applied to each wheel brake cylinder, the valve device having a pressure-increasing, pressure-holding and pressure-reducing states, and a reservoir for storing the fluid which has been discharged from each wheel brake cylinder through the pressure control valve device during the operation of the brake operating member, so that the fluid is returned from the reservoir to the hydraulic pressure source after the operation of the brake operating member. The reservoir has a storage capacity smaller than a maximum total amount of the fluid that can be accommodated in all of the at least one wheel brake cylinder during operation of the at least one wheel brake cylinder.
    Type: Grant
    Filed: March 9, 1998
    Date of Patent: December 26, 2000
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Akihiro Otomo, Kiyoharu Nakamura, Fumiaki Kawahata, Akira Sakai
  • Patent number: 6126248
    Abstract: In a hydraulic brake device, a pressurizing chamber receives a master cylinder pressure generated by a master cylinder. A pressure adjusting chamber receives an accumulator pressure generated by a high pressure source. A booster piston is movably provided between the pressurizing chamber and the pressure adjusting chamber. The booster piston is actuated in a first direction away from the pressurizing chamber by a pressure in the pressurizing chamber and actuated in a direction opposite to the first direction by a pressure in the pressure adjusting chamber. A flow control mechanism responsive to a movement of the booster piston is provided. The flow control mechanism makes the pressure adjusting chamber open to the high pressure source when the booster piston is moved in the first direction exceeding a predetermined distance, and closes the pressure adjusting chamber to be cut off from the high pressure source when the booster piston is moved in the opposite direction back to an initial position.
    Type: Grant
    Filed: July 27, 1998
    Date of Patent: October 3, 2000
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Fumiaki Kawahata, Masayasu Ohkubo
  • Patent number: 6123397
    Abstract: In a brake fluid control device, front wheel cylinders are connected to a front hydraulic circuit, and rear wheel cylinders are connected to a rear hydraulic circuit. The front hydraulic circuit and the rear hydraulic circuit are connected to a front left pressure-decrease valve, a front right pressure-decrease valve, a rear left pressure-decrease valve, a rear right pressure-decrease valve and a connecting pipe. When a brake pedal is depressed, the front left pressure-decrease valve, the front right pressure-decrease valve, the rear left pressure-decrease valve and the rear right pressure-decrease valve are opened and a master cylinder pressure sensor leads to both the front hydraulic circuit and the rear hydraulic circuit. Comparing a detection value of the of the master cylinder pressure sensor, a detection value of a front wheel cylinder pressure sensor and a detection value of a rear wheel cylinder pressure sensor respectively, detects the state of operation of each of the sensors provided in the system.
    Type: Grant
    Filed: September 24, 1997
    Date of Patent: September 26, 2000
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Akihiro Ohtomo, Akira Sakai, Fumiaki Kawahata, Hirohiko Morikawa, Kiyoharu Nakamura
  • Patent number: 6007164
    Abstract: A brake fluid pressure control apparatus achieves a sufficiently large brake force even when a malfunction occurs in an operational force sensor for detecting a level of operational force applied to a brake system. A magnitude of a master cylinder pressure generated by a master cylinder is detected by a master cylinder pressure sensor. A linear fluid pressure source generates a linear fluid pressure adjusted by the magnitude of the master cylinder pressure. Front wheel cylinders and rear wheel cylinders are provided with the linear fluid pressure. A front wheel cylinder pressure is detected and a front wheel cylinder pressure value corresponding to a magnitude of the front wheel cylinder pressure is output by a front wheel cylinder sensor. If it is determined that a malfunction is occurring in the operational force sensor, a connection of the front wheel cylinders is switched from the linear fluid pressure source to the master cylinder.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: December 28, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Akira Sakai, Akihiro Ohtomo, Fumiaki Kawahata, Hirohiko Morikawa, Kiyoharu Nakamura
  • Patent number: 5992949
    Abstract: A hydraulic brake control apparatus in which a master cylinder supplies a brake fluid pressure responsive to a brake operating force to wheel cylinders through a first valve, includes a first control unit which controls second valves and third valves when a brake fluid pressure supplied to the wheel cylinders by a pressure supplying device is detected to be excessively high under a condition in which the supply of the brake fluid pressure to the wheel cylinders by the master cylinder is inhibited by the first valve, so that the supply of the brake fluid pressure to the wheel cylinders by the pressure supplying device is inhibited by the second valves and a flow of the brake fluid from the wheel cylinders into a reservoir tank is allowed by the third valves.
    Type: Grant
    Filed: July 1, 1997
    Date of Patent: November 30, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Kiyoharu Nakamura, Fumiaki Kawahata, Masayasu Ohkubo, Hirohiko Morikawa, Akira Sakai, Akihiro Ohtomo
  • Patent number: 5984432
    Abstract: Hydraulic pressure control apparatus wherein a pressure difference across a seating valve disposed in a fluid passage acts on a valve member for placing the seating valve in an open state, while an elastic member biases the valve member for placing the seating valve in a closed state, and a valve driving device operated with an electric current applied thereto generates a drive force acting on the valve member so as to open the seating valve. A control device for controlling the electric current includes a stepping controller for incrementing the amount of the electric current when the seating valve is operated from the closed state into the open state, such that an increment of the electric current decreases with an increase in the pressure difference. The hydraulic pressure control apparatus may be suitably used in a vehicle braking system, for controlling fluid pressure in wheel brake cylinder.
    Type: Grant
    Filed: March 11, 1998
    Date of Patent: November 16, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Akihiro Otomo, Kiyoharu Nakamura, Fumiaki Kawahata, Akira Sakai, Shinichi Soejima
  • Patent number: 5979997
    Abstract: A hydraulic brake control apparatus includes a pressure supply inhibiting unit which inhibits supply of a brake fluid pressure to wheel cylinders by a first pressure supplying unit when a defect in a brake fluid path between a first flow control unit and the wheel cylinders has occurred, and inhibits supply of a brake fluid pressure to the wheel cylinders by a second pressure supplying unit when a defect in a brake fluid path between a second flow control unit and the wheel cylinders has occurred.
    Type: Grant
    Filed: June 27, 1997
    Date of Patent: November 9, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Masayasu Ohkubo, Fumiaki Kawahata, Amane Shimura, Hirohiko Morikawa, Akira Sakai, Akihiro Ohtomo
  • Patent number: 5951120
    Abstract: A hydraulic brake control apparatus in which a master cylinder is connected to wheel cylinders via a master cylinder cut valve, and the wheel cylinders are connected to a reservoir tank via a switching valve, includes a check valve provided between the master cylinder and the wheel cylinders in parallel with the master cylinder cut valve, the check valve provided in a bypass passage of the master cylinder cut valve, the check valve allowing a flow of a brake fluid from the master cylinder to the wheel cylinders and inhibiting a flow of the brake fluid from the wheel cylinders to the master cylinder.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: September 14, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Amane Shimura, Hirohiko Morikawa, Fumiaki Kawahata, Kiyoharu Nakamura, Akira Sakai, Akihiro Ohtomo
  • Patent number: 5895100
    Abstract: A brake apparatus for an electric vehicle which maintains the regenerative energy generated in a traction motor of each of wheels to be at a maximum. A hydraulic pressure brake and a regenerative brake are provided in the same brake apparatus. The hydraulic pressure brake generates a brake torque by providing a hydraulic pressure to a wheel cylinder of each wheel of the vehicle. The regenerative brake generates a brake torque by regeneration in a traction motor for each wheel. The brake torque to be provided is calculated for each wheel. A maximum regenerative energy is calculated for each wheel. A hydraulic pressure calculating unit calculates a hydraulic pressure to be provided to the wheel cylinder of each wheel based on the brake torque and the maximum regenerative energy so that the regenerative energy generated by the traction motor of each wheel becomes a maximum.
    Type: Grant
    Filed: January 27, 1997
    Date of Patent: April 20, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Masashi Ito, Fumiaki Kawahata, Masayasu Ohkubo, Kiyoharu Nakamura, Akira Sakai, Akihiro Otomo
  • Patent number: 5882089
    Abstract: A hydraulic brake system is provided which does not need a mechanism to feed back the wheel cylinder pressure. The hydraulic brake system generates a brake force by supplying the brake fluid to a wheel cylinder under a high pressure generated by a high pressure source. The brake fluid is supplied to the high pressure source from a reservoir tank storing the brake fluid under atmospheric pressure. A fluid passage connects the high pressure source to both the wheel cylinder and the reservoir tank. An amount of the brake fluid flowing from the high pressure source to the wheel cylinder is controlled by a constant flow valve.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: March 16, 1999
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Kiyoharu Nakamura, Fumiaki Kawahata, Masashi Ito
  • Patent number: 5727851
    Abstract: A hydraulic brake apparatus includes a control valve having a spool which is bi-directionally movable between a first position and a second position, the spool, when located at the first position, allowing brake fluid from a low-pressure source to pass through the control valve to a wheel cylinder, and the spool, when located at the second position, allowing brake fluid from a high-pressure source to pass through the control valve to the wheel cylinder. A first unit introduces brake fluid from the wheel cylinder into the control valve, the brake fluid having a wheel cylinder pressure exerted to move the spool in a first direction toward the first position. A second unit introduces brake fluid from a master cylinder into the control valve, the brake fluid having a master cylinder pressure exerted to move the spool in a second, reverse direction toward the second position. A third unit reduces the master cylinder pressure exerted on the spool.
    Type: Grant
    Filed: October 17, 1996
    Date of Patent: March 17, 1998
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Masayasu Ohkubo, Fumiaki Kawahata, Masashi Ito, Kiyoharu Nakamura
  • Patent number: 5711584
    Abstract: A hydraulic brake apparatus maintains a sufficient amount of brake fluid in a master cylinder when a failure occurs in a high pressure brake fluid source which provides a high pressure brake fluid to a wheel cylinder. The hydraulic brake apparatus generates a wheel cylinder pressure provided to the wheel cylinder by using a high pressure brake fluid provided by the high pressure brake fluid source. The wheel cylinder pressure is controlled in response to a master cylinder pressure generated by a master cylinder. A fluid pressure control valve, having a spool movable in response to the master cylinder pressure, connects one of the high pressure brake fluid source and a low pressure brake fluid source to the wheel cylinder so that the wheel cylinder pressure is controlled in response to the master cylinder pressure. A low pressure source passage connects the low pressure brake fluid source to the fluid pressure control valve so as to supply a low pressure brake fluid to the fluid pressure control valve.
    Type: Grant
    Filed: September 26, 1996
    Date of Patent: January 27, 1998
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Fumiaki Kawahata
  • Patent number: 5658057
    Abstract: A hydraulic braking apparatus for braking a vehicle wheel, wherein a pressure control valve is disposed between a master cylinder and a wheel brake cylinder, and between a reservoir and a hydraulic pressure source which is independent of the master cylinder and whose pressure is applied as a braking pressure to the wheel brake cylinder for braking the wheel. The pressure control valve controls the braking pressure as a function of the master cylinder pressure which is generated by the master cylinder, depending upon the operating force acting on a brake operating member. An electrically controlled pressure regulating device is provided for applying an electrically controlled force to the pressure control valve, to thereby regulate the braking pressure to be applied to the wheel brake cylinder.
    Type: Grant
    Filed: May 28, 1996
    Date of Patent: August 19, 1997
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yutaka Ohnuma, Kenji Shirai, Fumiaki Kawahata, Kiyoharu Nakamura, Mark Evans, Hiroaki Yoshida
  • Patent number: 4625904
    Abstract: A welding structure for a disc wheel installed on a vehicle. The disc wheel comprises a rim and a disc, the disc having an outer peripheral portion fixed to an inner surface of the rim by welding. The edge surface of the outer peripheral portion of the disc is inclined with respect to the rim, and when assembled contains the end portion of the weld.
    Type: Grant
    Filed: November 27, 1985
    Date of Patent: December 2, 1986
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Hitoshi Matsui, Fumiaki Kawahata