Patents by Inventor Takahisa Yokoyama

Takahisa Yokoyama 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: 7063393
    Abstract: In an electronic brake system, a brake pedal is operated by a driver according to a requisite braking force. Wheel cylinders equipped at respective vehicle wheels generate braking forces at the respective vehicle wheels. A master cylinder applies a brake fluid pressure to generate the respective wheel cylinder pressures. A pedal operation amount detection portion detects a stroke amount of the brake pedal. The brake pedal and the master cylinder are isolated from each other. The motor is driven based on the pedal operation amount detected by the pedal operation amount detection portion and then controls the brake fluid pressure.
    Type: Grant
    Filed: August 13, 2002
    Date of Patent: June 20, 2006
    Assignees: Advics Co., Ltd., Denso Corporation
    Inventors: Motoshi Suzuki, Haruo Arakawa, Takayuki Takeshita, Takahisa Yokoyama
  • Publication number: 20060118368
    Abstract: A motor driven brake apparatus is provided for braking a wheel mounted on a knuckle, and includes a brake member rotated integrally with the wheel, a friction member mounted on the knuckle to be capable of being in contact with the brake member, and an electric motor for driving the friction member toward the brake member to be in contact therewith. The motor is adapted to press the friction member onto the brake member to restrain the wheel from rotating. And, a motion converter is accommodated in an opening portion of the knuckle for converting rotating force of the motor into pressing force applied by the friction member onto the brake member. The motion converter is connected to the motor at a side thereof facing the vehicle body, and the motor is mounted on the knuckle.
    Type: Application
    Filed: December 1, 2005
    Publication date: June 8, 2006
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita, Chihiro Nitta
  • Publication number: 20060118367
    Abstract: A brake apparatus is provided for braking a vehicle wheel, and includes a brake member rotated integrally with the wheel, a friction member mounted on the vehicle to be in contact with the brake member, a rotation member rotated integrally with the wheel, an electric motor, and a differential shift device. A motion converter is provided for converting a rotating motion of the motor into a thrust motion of the friction member to be pressed onto the brake member. For example, one of three components of the differential shift device is movable in response to rotation of the rotation member, another one is movable in response to rotation of the electric motor, and the rest is movable in response to operation of the motion converter.
    Type: Application
    Filed: December 1, 2005
    Publication date: June 8, 2006
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita, Chihiro Nitta
  • Patent number: 7004551
    Abstract: A vehicular motor-driven brake apparatus includes an open circuit in which reciprocation of a master cylinder generating a brake pressure is caused by an actuator that operates according to a pedal operation amount, and brake fluid discharged from a wheel cylinder during pressure decrease is directly returned to a master reservoir subject to atmospheric pressure. A fluid amount replenishment control is executed during pressure increase of the master cylinder in which a master stroke is returned for only a predetermined time by operation of the actuator, and thus brake fluid is sucked up from the master reservoir to the master cylinder. Accordingly, when an ABS control continues for a long time period, even if the brake pedal is being depressed, reduced pressure brake fluid in the master cylinder is sucked up. Therefore, there is no limit to pressure decrease, and bottoming-out of the master cylinder does not occur.
    Type: Grant
    Filed: September 2, 2004
    Date of Patent: February 28, 2006
    Assignee: Advics Co., Ltd.
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Patent number: 7002314
    Abstract: The present invention provides an electric brake system which detects the occurrence of overshooting, and corrects a feedback gain in the PID feedback control at overshooting. For example, it increases a differential gain Kd. Accordingly, a damping force increases from the time when the overshooting is determined, and after the overshooting, the output of an electric brake moderately decays to get closer to the target value with the passage of time.
    Type: Grant
    Filed: July 27, 2004
    Date of Patent: February 21, 2006
    Assignee: ADVICS Co., Ltd.
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita
  • Publication number: 20050255955
    Abstract: An eccentric portion of a first shaft is supported by a pair of roller bearings. If moments are generated by meshing of an externally toothed gear and an internally toothed gear and inner pins and inner pin holes that configure a rotation control mechanism, the pair of bearings provide two point support for the externally toothed gear. Accordingly, the externally toothed gear is supported so as not to tilt with respect to the first shaft, and a configuration is provided in which point contact does not occur in the meshing area of the externally toothed gear and the internally toothed gear.
    Type: Application
    Filed: April 21, 2005
    Publication date: November 17, 2005
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita, Masashi Hori
  • Patent number: 6964461
    Abstract: The brake control apparatus sets a target deceleration (1) in accordance with an amount of operation of the brake pedal. It calculates another target deceleration (2) on the basis of the target deceleration (1). In this calculation, limit values of deceleration increasing and decreasing gradients with respect to the target deceleration (1) are set on the basis of the target deceleration (1), and then the target deceleration (2) is obtained by correcting the target deceleration (1) on the basis of the established deceleration increasing and decreasing gradients. Accordingly, the deceleration increasing/decreasing gradient becomes small when braking is gentle. This makes it possible to curb an abrupt change in brake force to achieve smooth brake control. Further, the deceleration increasing/decreasing gradient becomes larger when braking is abrupt. Accordingly, it is possible to create a great change in brake force to provide a high response.
    Type: Grant
    Filed: July 27, 2004
    Date of Patent: November 15, 2005
    Assignee: Advics Co., Ltd.
    Inventors: Takahisa Yokoyama, Haruo Arakawa, Takayuki Takeshita
  • Publication number: 20050146209
    Abstract: A vehicular motor-driven brake apparatus includes an open circuit in which reciprocation of a master cylinder generating a brake pressure is caused by an actuator that operates according to a pedal operation amount, and brake fluid discharged from a wheel cylinder during pressure decrease is directly returned to a master reservoir subject to atmospheric pressure. A fluid amount replenishment control is executed during pressure increase of the master cylinder in which a master stroke is returned for only a predetermined time by operation of the actuator, and thus brake fluid is sucked up from the master reservoir to the master cylinder. Accordingly, when an ABS control continues for a long time period, even if the brake pedal is being depressed, reduced pressure brake fluid in the master cylinder is sucked up. Therefore, there is no limit to pressure decrease, and bottoming-out of the master cylinder does not occur.
    Type: Application
    Filed: March 8, 2005
    Publication date: July 7, 2005
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Patent number: 6877821
    Abstract: A vehicular motor-driven brake apparatus includes an open circuit in which reciprocation of a master cylinder generating a brake pressure is caused by an actuator that operates according to a pedal operation amount, and brake fluid discharged from a wheel cylinder during pressure decrease is directly returned to a master reservoir subject to atmospheric pressure. A fluid amount replenishment control is executed during pressure increase of the master cylinder in which a master stroke is returned for only a predetermined time by operation of the actuator, and thus brake fluid is sucked up from the master reservoir to the master cylinder. Accordingly, when an ABS control continues for a long time period, even if the brake pedal is being depressed, reduced pressure brake fluid in the master cylinder is sucked up. Therefore, there is no limit to pressure decrease, and bottoming-out of the master cylinder does not occur.
    Type: Grant
    Filed: April 21, 2003
    Date of Patent: April 12, 2005
    Assignee: Advics Co., Ltd.
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Publication number: 20050059524
    Abstract: An internal planetary gear mechanism reduces a load applied to tooth surfaces of an external gear and an internal gear, a sliding portion such as a bearing and the like. By setting the amount of eccentricity ? of an eccentric part to be larger than a theoretical value, a distance between the center of the external gear and the center of the internal gear is increased to allow the reduction of a loss in the bearing and on the tooth surfaces of the gears, and a mesh zone between the internal gear and the external gear can be reduced to decrease a part at a large pressure angle, thereby reducing a loss generated by a large pressure angle. As a result of reduction in the mesh zone between the external gear and the internal gear, rolling contact of the gears is maintained.
    Type: Application
    Filed: August 30, 2004
    Publication date: March 17, 2005
    Applicant: DENSO CORPORATION
    Inventors: Masashi Hori, Masamichi Watanabe, Akihiko Takenaka, Takahisa Yokoyama, Takayuki Takeshita, Yuzo Imoto
  • Publication number: 20050046270
    Abstract: The present invention provides an electric brake system in which an actual control variable in the electric brake when overshooting is generated is determined, and the target value is set to a maximum value of the actual control variable in the electric brake when overshooting is generated. Therefore, the target value and the actual control variable will be in agreement with each other before hunting to be generated after overshooting starts. Accordingly, the output of the electric brake is gradually stabilizing at the target value without an oscillation phenomenon as in a related art.
    Type: Application
    Filed: August 5, 2004
    Publication date: March 3, 2005
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita
  • Publication number: 20050046368
    Abstract: The present invention provides an electric brake system which detects the occurrence of overshooting, and corrects a feedback gain in the PID feedback control at overshooting. For example, it increases a differential gain Kd. Accordingly, a damping force increases from the time when the overshooting is determined, and after the overshooting, the output of an electric brake moderately decays to get closer to the target value with the passage of time.
    Type: Application
    Filed: July 27, 2004
    Publication date: March 3, 2005
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita
  • Publication number: 20050040700
    Abstract: The brake control apparatus sets a target deceleration 1 in accordance with an amount of operation of the brake pedal. It calculates another target deceleration 2 on the basis of the target deceleration 1. In this calculation, limit values of deceleration increasing and decreasing gradients with respect to the target deceleration 1 are set on the basis of the target deceleration 1, and then the target deceleration 2 is obtained by correcting the target deceleration 1 on the basis of the established deceleration increasing and decreasing gradients. Accordingly, the deceleration increasing/decreasing gradient becomes small when braking is gentle. This makes it possible to curb an abrupt change in brake force to achieve smooth brake control. Further, the deceleration increasing/decreasing gradient becomes larger when braking is abrupt. Accordingly, it is possible to create a great change in brake force to provide a high response.
    Type: Application
    Filed: July 27, 2004
    Publication date: February 24, 2005
    Inventors: Takahisa Yokoyama, Haruo Arakawa, Takayuki Takeshita
  • Publication number: 20050039563
    Abstract: A brake operating apparatus includes a brake pedal lever pivotally attached to a bracket, an output member provided between the brake pedal lever and a brake actuating device, and a lever-ratio-changing mechanism provided between the brake pedal lever and the output member. The lever-ratio-changing mechanism includes a link member provided on one side of the brake pedal lever and rotatably attached thereto via a support shaft. The link member is linked to a rear end portion of the output member via a link shaft provided on the link member at a position offset radially from the support shaft by a predetermined amount. An interlocking mechanism is provided on the side of the brake pedal lever and between the stationary member and the link member. The interlocking mechanism causes the link member to rotate about the support shaft in accordance with pivotal movement of the brake pedal lever.
    Type: Application
    Filed: August 5, 2004
    Publication date: February 24, 2005
    Inventors: Haruo Arakawa, Takahisa Yokoyama, Takayuki Takeshita
  • Publication number: 20050029860
    Abstract: A vehicular motor-driven brake apparatus includes an open circuit in which reciprocation of a master cylinder generating a brake pressure is caused by an actuator that operates according to a pedal operation amount, and brake fluid discharged from a wheel cylinder during pressure decrease is directly returned to a master reservoir subject to atmospheric pressure. A fluid amount replenishment control is executed during pressure increase of the master cylinder in which a master stroke is returned for only a predetermined time by operation of the actuator, and thus brake fluid is sucked up from the master reservoir to the master cylinder. Accordingly, when an ABS control continues for a long time period, even if the brake pedal is being depressed, reduced pressure brake fluid in the master cylinder is sucked up. Therefore, there is no limit to pressure decrease, and bottoming-out of the master cylinder does not occur.
    Type: Application
    Filed: September 2, 2004
    Publication date: February 10, 2005
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Patent number: 6845852
    Abstract: A vehicular brake apparatus, which is provided at a shaft of a motor that revolves due to depression of a brake pedal, has a variable gear mechanism including a non-circular spur gear that changes a reduction ratio from a high gear ratio to a low gear ratio along with revolution. Revolution is converted to linear movement by roller bearings interposed between two ramp portions each having a straight inclined surface, and a friction member is pressed against a disk by a friction material holding portion being moved in a straight direction. Further, a braking force is generated on the disk by the friction member and another friction member provided on the opposite side of the caliper.
    Type: Grant
    Filed: March 19, 2003
    Date of Patent: January 25, 2005
    Assignee: Advics Co., Ltd.
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Patent number: 6844812
    Abstract: A brake operation amount detection device detects an operation amount of a brake pedal, and a target deceleration computation device computes a target deceleration corresponding to an operation amount that the driver intends to achieve. Further, an actual deceleration calculation device calculates an actual deceleration. A deviation between the target deceleration and the actual deceleration is obtained as a difference level, and a warning issuing device generates a sound having a volume that increases in accordance with the magnitude of the difference level. Accordingly, in the case that the brake does not act, contrary to the driver's expectation, even when the driver presses down the brake pedal, the driver can recognize a degree of difference from the driver's braking intention, based on the magnitude of the sound. Therefore, the driver does not feel a sense of danger or fear.
    Type: Grant
    Filed: June 25, 2003
    Date of Patent: January 18, 2005
    Assignee: Advics Co., Ltd.
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Publication number: 20040046652
    Abstract: A brake operation amount detection device detects an operation amount of a brake pedal, and a target deceleration computation device computes a target deceleration corresponding to an operation amount that the driver intends to achieve. Further, an actual deceleration calculation device calculates an actual deceleration. A deviation between the target deceleration and the actual deceleration is obtained as a difference level, and a warning issuing device generates a sound having a volume that increases in accordance with the magnitude of the difference level. Accordingly, in the case that the brake does not act, contrary to the driver's expectation, even when the driver presses down the brake pedal, the driver can recognize a degree of difference from the driver's braking intention, based on the magnitude of the sound. Therefore, the driver does not feel a sense of danger or fear.
    Type: Application
    Filed: June 25, 2003
    Publication date: March 11, 2004
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Publication number: 20040011603
    Abstract: A vehicular brake apparatus, which is provided at a shaft of a motor that revolves due to depression of a brake pedal, has a variable gear mechanism including a non-circular spur gear that changes a reduction ratio from a high gear ratio to a low gear ratio along with revolution. Revolution is converted to linear movement by roller bearings interposed between two ramp portions each having a straight inclined surface, and a friction member is pressed against a disk by a friction material holding portion being moved in a straight direction. Further, a braking force is generated on the disk by the friction member and another friction member provided on the opposite side of the caliper.
    Type: Application
    Filed: March 19, 2003
    Publication date: January 22, 2004
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa
  • Publication number: 20030201669
    Abstract: A vehicular motor-driven brake apparatus includes an open circuit in which reciprocation of a master cylinder generating a brake pressure is caused by an actuator that operates according to a pedal operation amount, and brake fluid discharged from a wheel cylinder during pressure decrease is directly returned to a master reservoir subject to atmospheric pressure. A fluid amount replenishment control is executed during pressure increase of the master cylinder in which a master stroke is returned for only a predetermined time by operation of the actuator, and thus brake fluid is sucked up from the master reservoir to the master cylinder. Accordingly, when an ABS control continues for a long time period, even if the brake pedal is being depressed, reduced pressure brake fluid in the master cylinder is sucked up. Therefore, there is no limit to pressure decrease, and bottoming-out of the master cylinder does not occur.
    Type: Application
    Filed: April 21, 2003
    Publication date: October 30, 2003
    Inventors: Takahisa Yokoyama, Takayuki Takeshita, Haruo Arakawa