Patents by Inventor Tatsuo Wakahara

Tatsuo Wakahara 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: 7229372
    Abstract: During a downshift of a belt-drive continuously variable transmission, occurring owing to vehicle deceleration, a CVT controller foretells that a slippage between a drive belt and each of primary and secondary variable-width pulleys tends to occur, when a primary pulley pressure is less than a first predetermined pressure level and a primary pulley speed is less than a first predetermined rotational speed. When the belt slippage has been foretold, the CVT controller inhibits the primary pulley pressure from dropping by setting an actual transmission ratio calculated before a set time period from a time when the slippage has been foretold or a transmission ratio of a relatively higher speed side as compared with a ratio-change operating state obtained when the slippage has been foretold, to a desired transmission ratio, or by relatively rising a line pressure as compared with a line pressure level produced when the slippage has been foretold.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: June 12, 2007
    Assignee: JATCO Ltd
    Inventors: Shigeki Shimanaka, Hiroyasu Tanaka, Youhei Ishikawa, Tatsuo Wakahara, Yoshihisa Kodama, Hideki Oshita
  • Patent number: 7192383
    Abstract: In control apparatus and method for an automotive vehicle, the vehicle having a continuously variable transmission associated with a vehicular engine and including a belt that transmits a revolution of a primary pulley to a secondary pulley that is enabled to make a gear shift by modifying a pulley ratio between the primary and secondary pulleys with a hydraulic, a determination is made as to whether a belt slip between at least one of the primary and the secondary pulleys occurs and an output section outputs a signal to command an engine control unit to increase an engine speed by a predetermined engine speed when the belt slip is determined to occur.
    Type: Grant
    Filed: September 25, 2003
    Date of Patent: March 20, 2007
    Assignees: Jatco Ltd, Nissan Motor Co., Ltd.
    Inventors: Tetsuya Shimada, Masahiro Iriyama, Kenichi Gotou, Masahiro Yamamoto, Yoshihisa Kodama, Shigeki Shimanaka, Hiroyasu Tanaka, Takuichiro Inoue, Tatsuo Wakahara, Hisao Nobu
  • Patent number: 7169070
    Abstract: There are provided with a determination means for determining whether or not the correlation between the pressure value detected by the primary pressure sensor and the pressure value detected by the secondary pressure sensor is an actually impossible relation (Step 5), and a switchover means for switching over to an open control while prohibiting a feedback control when the correlation is determined to have become a relation actually impossible by the determination means (Step 6). Presence or absence of a fault to the primary pressure sensor or the secondary pressure sensor (particularly, fault of fixed output voltage) is judged based on the correlation between the output voltage of the primary pressure sensor and the output voltage of the secondary pressure sensor to prohibit the control of a primary pressure and a secondary pressure using the hydraulic pressure sensors when it is judged that there is a fault.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: January 30, 2007
    Assignee: Jatco Ltd.
    Inventors: Tateki Jozaki, Shigeru Ishii, Tatsuo Wakahara, Masahiro Yamamoto, Hiroyasu Tanaka, Youhei Ishikawa
  • Patent number: 7112154
    Abstract: Hydraulic control system and method for an automatic transmission. The hydraulic control system includes a hydraulic pressure source, a flow rate control valve having a spool with an orifice and a drain hole, stroke position determining means, and pressure regulator means. The stroke position determining means determines that the spool is displaced from a large spool-stroke position where a communication area of the drain hole is not less than a first predetermined area, to a small spool-stroke position where the communication area is not more than a second predetermined area. The pressure regulator means regulates a hydraulic oil pressure downstream of the orifice and corrects the hydraulic oil pressure downstream of the orifice by adding a predetermined correction amount for a first predetermined time when the stroke position determining means determines that the spool is displaced from the large stroke position to the small stroke position.
    Type: Grant
    Filed: November 25, 2003
    Date of Patent: September 26, 2006
    Assignee: JATCO Ltd
    Inventors: Tatsuo Wakahara, Yoshihisa Kodama, Masahiro Yamamoto, Taichirou Yokoyama
  • Patent number: 7037235
    Abstract: A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve that compares a variable ASTP representing a step position of the step motor and a step position BSTP of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP?BSTP is satisfied determines that a step-out has occurred on the step motor.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: May 2, 2006
    Assignee: JATCO Ltd
    Inventors: Tateki Jozaki, Shigeru Ishii, Tatsuo Wakahara, Masahiro Yamamoto, Hiroyasu Tanaka, Shigeki Shimanaka, Midori Yamaguchi
  • Publication number: 20050192153
    Abstract: There are provided with a determination means for determining whether or not the correlation between the pressure value detected by the primary pressure sensor and the pressure value detected by the secondary pressure sensor is an actually impossible relation (Step 5), and a switchover means for switching over to an open control while prohibiting a feedback control when the correlation is determined to have become a relation actually impossible by the determination means (Step 6). Presence or absence of a fault to the primary pressure sensor or the secondary pressure sensor (particularly, fault of fixed output voltage) is judged based on the correlation between the output voltage of the primary pressure sensor and the output voltage of the secondary pressure sensor to prohibit the control of a primary pressure and a secondary pressure using the hydraulic pressure sensors when it is judged that there is a fault.
    Type: Application
    Filed: September 26, 2003
    Publication date: September 1, 2005
    Applicant: JATCO Ltd
    Inventors: Tateki Jozaki, Shigeru Ishii, Tatsuo Wakahara, Masahiro Yamamoto, Hiroyasu Tanaka, Youhei Ishikawa
  • Patent number: 6916269
    Abstract: In a V-belt type CVT, an actual-shift-ratio corresponding operated position of a step motor is calculated through conversion of an actual shift ratio expressed by the rotational-speed ratio between primary and secondary pulleys. A displacement amount is calculated between the actual-shift-ratio corresponding operated position of the step motor and an actual position thereof. A correction amount of the line pressure is calculated to reduce the displacement amount, and the line pressure is corrected in accordance therewith.
    Type: Grant
    Filed: September 4, 2003
    Date of Patent: July 12, 2005
    Assignee: Jatco Ltd.
    Inventors: Masahiro Yamamoto, Midori Yamaguchi, Toshiji Iida, Tatsuo Wakahara, Makoto Sawada
  • Publication number: 20040162183
    Abstract: Hydraulic control system and method for an automatic transmission. The hydraulic control system includes a hydraulic pressure source, a flow rate control valve having a spool with an orifice and a drain hole, stroke position determining means, and pressure regulator means. The stroke position determining means determines that the spool is displaced from a large spool-stroke position where a communication area of the drain hole is not less than a first predetermined area, to a small spool-stroke position where the communication area is not more than a second predetermined area. The pressure regulator means regulates a hydraulic oil pressure downstream of the orifice and corrects the hydraulic oil pressure downstream of the orifice by adding a predetermined correction amount for a first predetermined time when the stroke position determining means determines that the spool is displaced from the large stroke position to the small stroke position.
    Type: Application
    Filed: November 25, 2003
    Publication date: August 19, 2004
    Applicant: JATCO Ltd
    Inventors: Tatsuo Wakahara, Yoshihisa Kodama, Masahiro Yamamoto, Taichirou Yokoyama
  • Publication number: 20040127313
    Abstract: During a downshift of a belt-drive continuously variable transmission, occurring owing to vehicle deceleration, a CVT controller foretells that a slippage between a drive belt and each of primary and secondary variable-width pulleys tends to occur, when a primary pulley pressure is less than a first predetermined pressure level and a primary pulley speed is less than a first predetermined rotational speed. When the belt slippage has been foretold, the CVT controller inhibits the primary pulley pressure from dropping by setting an actual transmission ratio calculated before a set time period from a time when the slippage has been foretold or a transmission ratio of a relatively higher speed side as compared with a ratio-change operating state obtained when the slippage has been foretold, to a desired transmission ratio, or by relatively rising a line pressure as compared with a line pressure level produced when the slippage has been foretold.
    Type: Application
    Filed: September 26, 2003
    Publication date: July 1, 2004
    Applicant: JATCO Ltd
    Inventors: Shigeki Shimanaka, Hiroyasu Tanaka, Youhei Ishikawa, Tatsuo Wakahara, Yoshihisa Kodama, Hideki Oshita
  • Publication number: 20040116245
    Abstract: In a V-belt type CVT, an actual-shift-ratio corresponding operated position of a step motor is calculated through conversion of an actual shift ratio expressed by the rotational-speed ratio between primary and secondary pulleys. A displacement amount is calculated between the actual-shift-ratio corresponding operated position of the step motor and an actual position thereof. A correction amount of the line pressure is calculated to reduce the displacement amount, and the line pressure is corrected in accordance therewith.
    Type: Application
    Filed: September 4, 2003
    Publication date: June 17, 2004
    Applicant: JATCO Ltd.
    Inventors: Masahiro Yamamoto, Midori Yamaguchi, Toshiji Iida, Tatsuo Wakahara, Makoto Sawada
  • Publication number: 20040110599
    Abstract: A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve comprising a step-out determination means that compares a variable (ASTP) representing a step position of the step motor and a step position (BSTP) of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP≠BSTP is satisfied determines that a step-out has occurred on the step motor; a step-out correction means (S17d,S17f) that when a step-out is determined by the step-out determination means (S17b) corrects the ASTP so as to reduce a difference between the ASTP and the BSTP; and a drive means for driving the step motor using the corrected ASTP. The speed change ratio control unit for a continuously variable transmission is provided that can detect and correct a step-out at any speed change ratio.
    Type: Application
    Filed: September 26, 2003
    Publication date: June 10, 2004
    Applicant: JATCO Ltd
    Inventors: Tateki Jozaki, Shigeru Ishii, Tatsuo Wakahara, Masahiro Yamamoto, Hiroyasu Tanaka, Shigeki Shimanaka, Midori Yamaguchi
  • Publication number: 20040063537
    Abstract: In control apparatus and method for an automotive vehicle, the vehicle having a continuously variable transmission associated with a vehicular engine and including a belt that transmits a revolution of a primary pulley to a secondary pulley that is enabled to make a gear shift by modifying a pulley ratio between the primary and secondary pulleys with a hydraulic, a determination is made as to whether a belt slip between at least one of the primary and the secondary pulleys occurs and an output section outputs a signal to command an engine control unit to increase an engine speed by a predetermined engine speed when the belt slip is determined to occur.
    Type: Application
    Filed: September 25, 2003
    Publication date: April 1, 2004
    Applicant: JATCO Ltd and NISSAN MOTOR CO., LTD.
    Inventors: Tetsuya Shimada, Masahiro Iriyama, Kenichi Gotou, Masahiro Yamamoto, Yoshihisa Kodama, Shigeki Shimanaka, Hiroyasu Tanaka, Takuichiro Inoue, Tatsuo Wakahara, Hisao Nobu
  • Patent number: 6419059
    Abstract: A lock-up control device controls a lock-up clutch in a torque converter. The lock-up clutch is engaged by supplying a lock-up control pressure. The torque converter transmits torque via oil in a torque converter chamber when the lock-up clutch is disengaged, and transmits torque directly when the lock-up clutch is engaged. In the lock-up state, the oil pressure in the torque converter chamber is decreased by discharging oil in the torque converter chamber. By providing a circuit which leads oil discharged from the torque converter chamber to a lubricating part of the transmission, the balance between the inflowing oil amount and outflowing oil amount is improved, and oil insufficiency is prevented.
    Type: Grant
    Filed: October 16, 2000
    Date of Patent: July 16, 2002
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Hisao Nobu, Tatsuo Wakahara
  • Patent number: 6375591
    Abstract: A valve (13, 14) causes fluid pressures to act individually on plural frictional elements (A, B) of an automatic transmission so as to selectively lock the rotation of the frictional elements (A, B). A control unit (21) determines that the automatic transmission has an interlock tendency when the fluid pressures acting on the frictional elements (A, B) detected by pressure sensors (24, 25) are both equal to or greater than a predetermined pressure. Completion of a gear position change-over is detected by a sensor (23, 26), and the control unit (21) does not determine the interlock tendency until a predetermined time &Dgr;t has elapsed after the gear position change-over is complete. In this way, an incorrect determination is prevented by avoiding the determination in a period when the pressures are unstable in a period immediately after the gear position change-over of the automatic transmission.
    Type: Grant
    Filed: October 18, 2000
    Date of Patent: April 23, 2002
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Tatsuo Wakahara, Kenichiro Murakami
  • Patent number: 6374973
    Abstract: A lock-up control device comprises an inlet circuit which supplies oil to a torque converter chamber, an outlet circuit which discharges oil from the torque converter chamber, a signal output circuit which outputs a signal pressure according to a required engaging capacity of a lock-up clutch, and a lock-up control valve which outputs a lock-up control pressure according to the signal pressure from the signal output device. A lock-up control pressure which is fed back is input to the lock-up control valve so as to decrease the lock-up control pressure, and the pressure of the inlet circuit and pressure of the outlet circuit are input to the lock-up control valve so as to increase the lock-up control pressure. In this way, the pressure in the converter chamber is accurately reflected, and the lock-up control pressure is controlled so that a pressure differential between the lock-up control pressure and the torque converter chamber is a desired value.
    Type: Grant
    Filed: October 16, 2000
    Date of Patent: April 23, 2002
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Hisao Nobu, Tatsuo Wakahara
  • Patent number: 6106433
    Abstract: A motor vehicle includes an internal combustion engine and an automatic transmission powered by the engine. The engine has a throttle valve for controlling the amount of air fed thereto. The transmission selectively assumes an Over-drive possible D-range wherein both a lock-up ON condition and a lock-up OFF condition are available and an Over-drive impossible D-range wherein only the lock-up OFF condition is kept. A control system comprises a first section for detecting a first condition of the engine wherein an open degree of the throttle valve is reduced to a certain degree; a second section for detecting a second condition of the transmission wherein the lock-up ON condition of the Over-drive possible D-range is kept; and a third section for engaging a friction element of the transmission to induce an engine brake when the first and second sections detect the first and second conditions respectively.
    Type: Grant
    Filed: September 4, 1998
    Date of Patent: August 22, 2000
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Satoshi Sakakibara, Kazuhiro Takatori, Tatsuo Wakahara
  • Patent number: 6102831
    Abstract: A releasable coupling control system in combination with an electronic engine control unit executable a fuel cutoff mode during vehicle deceleration and re-startable a fuel-supply recovery mode as soon as an engine speed drops below a predetermined threshold value, for controlling engaging and disengaging operations of a releasable coupling device placed in an automotive power train between an engine and drive wheels, comprises a wheel-speed sensor for detecting a drive-wheel speed to generate a drive-wheel speed indicative signal, and a controller being configured to be responsive to the drive-wheel speed indicative signal for moderately releasing the releasable coupling device at a moderate turn-off mode when the drive-wheel speed indicative signal value drops below a first predetermined value, and for quickly releasing the releasable coupling device at a quick turn-off mode when the drive-wheel speed indicative signal value drops below a second predetermined value.
    Type: Grant
    Filed: April 8, 1998
    Date of Patent: August 15, 2000
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Tatsuo Wakahara, Chusaku Udagawa
  • Patent number: 5935043
    Abstract: A lockup control apparatus of a torque converter for a vehicle comprises a coast condition detecting section for detecting coast running of a vehicle, a lockup clutch slip detecting section for detecting a target slip generated between the input and output elements of the torque converter and a slip start capacity storing section, and a coast lockup control section for detecting a lockup capacity. The slip start capacity storing section detects a slip start capacity by once decreasing the lockup capacity to the sum of a last stored slip start capacity and a preset capacity and stores the slip start capacity while updating it. During the coast running a coast lockup control section controls the lockup capacity at a minimum lockup engagement capacity which is the sum of the newest slip start capacity and a predetermined capacity.
    Type: Grant
    Filed: April 24, 1998
    Date of Patent: August 10, 1999
    Assignee: Nissan Motor Co., Ltd
    Inventors: Akira Watanabe, Kazutaka Adachi, Shigeru Ishii, Tatsuo Wakahara
  • Patent number: 5875865
    Abstract: A hydraulic-pressure control system for a four-wheel drive vehicle with a hydraulic-pressure operated transfer clutch, which is responsive to a controlled clutch pressure applied thereto to distribute a driving torque passing from a transmission between main drive wheels and auxiliary drive wheels, comprises a pilot-operated directional control valve connected to the transfer clutch for cutting off a supply of hydraulic fluid of the controlled clutch pressure to the transfer clutch and for directing hydraulic fluid of the controlled clutch pressure to the transfer clutch. The system includes a clutch pressure control valve provided upstream of the directional control valve, which pressure control valve is responsive to an external pilot pressure for producing the controlled clutch pressure, and a duty-ratio controlled solenoid valve for decreasingly adjusting the external pilot pressure to be output to the pressure-reduction valve in accordance with an increase in a duty ratio.
    Type: Grant
    Filed: February 12, 1996
    Date of Patent: March 2, 1999
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Tatsuo Wakahara, Kenichiro Murakami
  • Patent number: 5819192
    Abstract: There is disclosed a motor vehicle having a set of front wheels, a set of rear wheels, an engine, and a transmission driven by the engine and having a transmission output shaft. The motor vehicle further has a transfer including a variable torque trasmitting (VTT) clutch for varying a distribution of torque between the set of front wheels and the set of rear wheels depending upon degree of engagement thereof. A clutch activating pressure is generated and transmitted to the VTT clutch under the control of a mode selector valve.
    Type: Grant
    Filed: September 9, 1997
    Date of Patent: October 6, 1998
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Tatsuo Wakahara, Kenichirou Murakami, Masaki Ohki, Koichi Hayasaki