Patents by Inventor Kotaro Koyama
Kotaro Koyama 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).
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Publication number: 20150217742Abstract: A brake apparatus includes a closed circuit including a pump configured to increase hydraulic pressures in wheel cylinders mounted on wheels with use of brake fluid drawn from a master cylinder. The brake apparatus includes a primary system hydraulic passage connecting at least one wheel cylinder of the wheel cylinders and a first chamber in the master cylinder to each other, and a secondary system hydraulic passage connecting remaining wheel cylinder of the wheel cylinders and a second chamber in the master cylinder to each other. The pump is connected so as to be able to supply the brake fluid to the primary system hydraulic passage and the secondary system hydraulic passage.Type: ApplicationFiled: February 3, 2015Publication date: August 6, 2015Applicant: HITACHI AUTOMOTIVE SYSTEMS, LTDInventor: Kotaro KOYAMA
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Patent number: 8991942Abstract: A brake control apparatus for a vehicle provided with a regenerative braking system includes a hydraulic circuit where a first passage connects a master cylinder to a wheel cylinder. A second passage connects a discharge side of a pump to a first portion of the first passage. A third passage connects a suction side of the pump to a second portion of the first passage between the master cylinder and the first portion. A fourth passage connects the suction side of the pump to a third portion of the first passage between an inflow valve and the wheel cylinder. A reservoir is connected to the third passage and a portion of the fourth passage between an outflow valve and the suction side of the pump. A shut-off valve restricts brake fluid discharge through a discharge-side valve from the pump being driven.Type: GrantFiled: April 13, 2012Date of Patent: March 31, 2015Assignee: Hitachi Automotive Systems, Ltd.Inventor: Kotaro Koyama
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Patent number: 8727455Abstract: A brake control apparatus for a vehicle having a regenerative braking system, has first to fourth brake circuits, a pump, a gate-out valve, an inflow valve, an outflow valve, a reservoir, a fluid suction cylinder, a branch oil passage, a switch valve, a regulation valve, and a hydraulic pressure control unit. The hydraulic pressure control unit controls a brake fluid pressure by operating the gate-out valve, the inflow valve, the outflow valve, the switch valve and the pump in accordance with a regenerative operation state of the regenerative braking system. Also the hydraulic pressure control unit stores the brake fluid flowing out from a master cylinder in the fluid suction cylinder by operating the pump when the regenerative braking system works, and supplies the brake fluid stored in the fluid suction cylinder to a wheel cylinder when a regenerative braking amount of the regenerative braking system lowers.Type: GrantFiled: October 20, 2011Date of Patent: May 20, 2014Assignee: Hitachi Automotive Systems, Ltd.Inventors: Motohiro Higuma, Kotaro Koyama
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Publication number: 20130138316Abstract: A brake control apparatus includes a parking-brake mechanism configured to apply braking force to left and right wheels of one of front and rear of a vehicle by a switching operation of a driver; a braking-force generating section configured to apply braking force independently to the wheels in accordance with a state of the vehicle; a moving-state judging section configured to judge whether or not the vehicle is moving; and a braking-force control unit configured to control the braking-force generating section. The braking-force control unit includes a braking-force cooperative control section configured to restrict an actuation of the parking-brake mechanism and to cause the braking-force generating section to generate braking force in a case that the parking-brake mechanism is required to be actuated by the switching operation when the moving-state judging section determines that the vehicle is moving.Type: ApplicationFiled: September 13, 2012Publication date: May 30, 2013Applicant: Hitachi Automotive Systems, Ltd.Inventor: Kotaro KOYAMA
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Publication number: 20120319465Abstract: A brake control apparatus for a vehicle provided with a regenerative braking system includes a hydraulic circuit where a first passage connects a master cylinder to a wheel cylinder. A second passage connects a discharge side of a pump to a first portion of the first passage. A third passage connects a suction side of the pump to a second portion of the first passage between the master cylinder and the first portion. A fourth passage connects the suction side of the pump to a third portion of the first passage between an inflow valve and the wheel cylinder. A reservoir is connected to the third passage and a portion of the fourth passage between an outflow valve and the suction side of the pump. A shut-off valve restricts brake fluid discharge through a discharge-side valve from the pump being driven.Type: ApplicationFiled: April 13, 2012Publication date: December 20, 2012Applicant: Hitachi Automotive Systems, Ltd.Inventor: Kotaro KOYAMA
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Publication number: 20120161504Abstract: A brake control apparatus for a vehicle having a regenerative braking system, has first to fourth brake circuits, a pump, a gate-out valve, an inflow valve, an outflow valve, a reservoir, a fluid suction cylinder, a branch oil passage, a switch valve, a regulation valve, and a hydraulic pressure control unit. The hydraulic pressure control unit controls a brake fluid pressure by operating the gate-out valve, the inflow valve, the outflow valve, the switch valve and the pump in accordance with a regenerative operation state of the regenerative braking system. Also the hydraulic pressure control unit stores the brake fluid flowing out from a master cylinder in the fluid suction cylinder by operating the pump when the regenerative braking system works, and supplies the brake fluid stored in the fluid suction cylinder to a wheel cylinder when a regenerative braking amount of the regenerative braking system lowers.Type: ApplicationFiled: October 20, 2011Publication date: June 28, 2012Inventors: Motohiro HIGUMA, Kotaro Koyama
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Publication number: 20120161505Abstract: A brake control apparatus for a vehicle having a regenerative braking system, has a pump, a first brake circuit connecting a master cylinder and a wheel cylinder, a second brake circuit, a gate-out valve, a third brake circuit, an inflow valve, a fourth brake circuit connecting a point positioned at the wheel cylinder side with respect to the inflow valve and the pump, an outflow valve, a reservoir, a fluid suction part into which the brake fluid flows, a cut-off valve, a check valve, a branch oil passage connecting to the fluid suction part, a fifth brake circuit connecting to the reservoir, a stroke simulator valve regulating brake fluid amount flowing into the reservoir from the master cylinder, and a hydraulic pressure control unit. The hydraulic pressure control unit controls brake fluid pressure by operating each valve and the pump according to regenerative operation state of the regenerative braking system.Type: ApplicationFiled: October 20, 2011Publication date: June 28, 2012Inventor: Kotaro Koyama
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Publication number: 20100191423Abstract: In a vehicle rollover prevention control apparatus employing a brake system serving as an actuator configured to control a dynamic behavior of a vehicle, a steering-input decision section is provided to make a rollover prediction, based on a driver-applied steering input, whether a predetermined level of roll motion for the vehicle occurs, and also to detect a driver-applied steering-back action. Also provided is an active rollover prevention control intervention decision section configured to make a rollover decision about rollover of the vehicle when the driver-applied steering-back action has been detected. An active rollover prevention control section is configured to execute rollover prevention control by controlling the actuator, when it is predicted for the predetermined level of roll motion to occur by the steering-input decision section and the rollover decision that rollover will occur has been made by the active rollover prevention control section.Type: ApplicationFiled: December 29, 2009Publication date: July 29, 2010Inventors: Kotaro KOYAMA, Motohiro Higuma
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Patent number: 7165818Abstract: In a vehicle attitude control system of an automotive vehicle employing a pump-and-motor assembly, and a hydraulic actuator that regulates fluid pressures in wheel-brake cylinders of road wheels of the vehicle, independently of each other, a control unit is electronically connected to at least a motor of the pump-and-motor assembly and the hydraulic actuator, for executing vehicle attitude control by controlling a discharge pressure of the motor-driven pump and by controlling the fluid pressures in the wheel-brake cylinders to respective desired fluid pressures independently of each other. A processing unit of the control unit is programmed to determine a duty ratio of a drive signal of the motor, based on the desired fluid pressure of at least one of the wheel-brake cylinders.Type: GrantFiled: August 18, 2004Date of Patent: January 23, 2007Assignee: Hitachi, Ltd.Inventors: Katsuya Iwasaki, Kotaro Koyama, Jun Kubo
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Publication number: 20050040704Abstract: In a vehicle attitude control system of an automotive vehicle employing a pump-and-motor assembly, and a hydraulic actuator that regulates fluid pressures in wheel-brake cylinders of road wheels of the vehicle, independently of each other, a control unit is electronically connected to at least a motor of the pump-and-motor assembly and the hydraulic actuator, for executing vehicle attitude control by controlling a discharge pressure of the motor-driven pump and by controlling the fluid pressures in the wheel-brake cylinders to respective desired fluid pressures independently of each other. A processing unit of the control unit is programmed to determine a duty ratio of a drive signal of the motor, based on the desired fluid pressure of at least one of the wheel-brake cylinders.Type: ApplicationFiled: August 18, 2004Publication date: February 24, 2005Inventors: Katsuya Iwasaki, Kotaro Koyama, Jun Kubo
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Patent number: 6685279Abstract: A brake control system includes an ECU constructed to carry out pressure-increase assist control for restraining the opening of an OUT-side gate valve and opening inlet valves during a predetermined time when active brake control is switched from the state that it is effective for only one wheel cylinder to the state that it is effective for only another wheel cylinder.Type: GrantFiled: January 14, 2003Date of Patent: February 3, 2004Assignee: Hitachi Unisia Automotive, Ltd.Inventor: Kotaro Koyama
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Publication number: 20030132665Abstract: A brake control system includes an ECU constructed to carry out pressure-increase assist control for restraining the opening of an OUT-side gate valve and opening inlet valves during a predetermined time when active brake control is switched from the state that it is effective for only one wheel cylinder to the state that it is effective for only another wheel cylinder.Type: ApplicationFiled: January 14, 2003Publication date: July 17, 2003Applicant: HITACHI UNISIA AUTOMOTIVE, LTD.Inventor: Kotaro Koyama