Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Tokico, Ltd.

Tohma Yamaguchi

Hiroki Takeda

Yukio Ohtani

Daisuke Goto

Toshiyuki Ajima

Kimihisa Furukawa

Kentaro Ueno

Hirotaka Oikawa

Takuya Usui

Youichi Kumemura

Daisuke Kojima

Yukihiko Yamada

Yusuke Nozawa

Nobuyuki Ichimaru

Toshio Takayama

Shigehisa Aoyagi

Mitsuhide Sasaki

Masaru Sakuma

Masaki Kashima

Kentarou Ueno

Yoshinari Kawahara

Makoto Matsuura

Tatsuji Ohkubo

Takashi Nishitsuka

An ECU () outputs control signals to an electric booster () of a fluid-pressure generating device () and to an ESC (). In this way, the establishment and cutting off of communication through pressure-increase control valves (), ('), (), and (&#x2032;) of the ESC () are controlled to connect each of wheel cylinders () to () in turn to the master cylinder (). In doing so, the electric booster () is controlled for each of the wheel cylinders () to () to measure a stroke of a piston (), () of a master cylinder (), or a volume of brake fluid proportional to the stroke of the piston (), (), and a fluid pressure detected by fluid-pressure sensors () and (). The fluid volume-pressure characteristic of each of the wheel cylinders () to () so determined is used for comparison to detect any atmospheric air in each pipeline.

Brake apparatus and method for detecting air in pipelines of the brake apparatus

A brake control device capable of preventing a braking force from being excessive when information cannot be transmitted between a first control unit configured to control operation of a boost mechanism and a second control unit configured to control operation of a hydraulic control mechanism. When a second ECU () cannot transmit information to a first ECU () due to a disconnection of a signal line (), the second ECU carries out backup control of detecting a braking operation amount of a driver based on signal input from hydraulic pressure sensors (), and operating a hydraulic pressure supply device () based on the detected braking operation amount, to thereby pressurize insides of wheel cylinders. In this case, the second ECU decreases a pressurization amount of a pressure inside the wheel cylinders when a pressure of a master cylinder () exceeds a predetermined value (PM) during the backup control.

Brake control device

An inverter device includes a source current calculator and an inverter circuit, wherein: the source current calculator calculates an average value of the DC bus current Ical during a PWM cycle through arithmetic operation executed based upon instantaneous values of the DC bus current Idc of the inverter circuit; and the source current calculator provides an estimated value by designating the average current value Ical during the PWM cycle as an input source current Isrc during the PWM cycle.

Inverter device

An objective of the present invention is to improve current detection accuracy and to reduce noise of carrier frequency. A motor apparatus and a motor drive apparatus calculate motor currents Iu, Iv, and Iw using a DC bus current detected value Idc of an inverter and control a magnitude and a phase of an applied voltage of a motor to drive the motor. A carrier adjuster decreases a carrier frequency Fc of the inverter if a motor output is relatively larger and that increases the carrier frequency Fc of the inverter if the motor output is relatively smaller. A pulse shift adjuster shifts an interphase waveform of a PWM pulse according to the carrier frequency Fc.

Inverter apparatus

An electric motor is controlled based on an operation of a brake pedal to move a primary piston forward through a ball screw mechanism, thereby generating a hydraulic pressure in a master cylinder. At this time, a reaction force from the hydraulic pressure in the master cylinder is fed back to the brake pedal through an input piston. Automatic brake control, which generates the hydraulic pressure by driving the electric motor regardless of whether there is the operation of the brake pedal, is carried out. During the automatic brake control, an actual relative position is compared with a determination threshold value set based on the relative position between the primary piston and the input piston which is generated by a movement of the primary piston, and it is determined that the brake pedal is operated in a case where the relative position is smaller than the determination threshold value.

Electric booster

A controller sets a target hydraulic pressure of a master cylinder based on the operation amount of a brake pedal, and controls the action of an electric motor so that a master cylinder hydraulic pressure attains the target hydraulic pressure. A brake characteristic representing a relationship between a motor rotation position detected by a resolver and the master cylinder hydraulic pressure as detected by the hydraulic pressure sensor is stored and updated. When the hydraulic pressure sensor is abnormal, a target motor rotation position corresponding to the target hydraulic pressure is set using the updated brake characteristic, and the action of the electric motor is controlled. The electric motor is controlled based on the updated brake characteristic, and hence fluctuations in the vehicle deceleration with respect to the brake operation can be suppressed and a sense of discomfort for the driver can be alleviated.

Brake control apparatus

A brake control system displaces a primary piston by controlling an operation of the electric motor by a master pressure control unit according to the operation amount (Xop) of the brake pedal, thereby generating a hydraulic pressure in the master cylinder to supply it to wheel cylinders (Ba to Bd). The master pressure control unit sets a target relative displacement (&#x394;XT) between an input piston and the primary piston and a target hydraulic pressure (PT) in the master cylinder, and appropriately switch which is used to control a brake force. During regenerative cooperation, the master pressure control unit selects the control with use of the target hydraulic pressure, which enables easy execution of a hydraulic pressure control including a subtraction of the hydraulic pressure corresponding to a brake effect from the regenerative cooperation.

Brake control system

A motor-driven disk brake system is capable of preventing a pressing member from moving beyond a predetermined position at a time of stopping a motor. When a command for system termination is issued, motor current is reduced intermittently, which correspondingly reduces a motor displacement gradually such that a return force is spent gradually on a return displacement of a motor and a piston, thereby preventing a rotational speed of a rotor from increasing. A large accelerated backward movement of the motor and the piston beyond a predetermined position due to inertia is thereby prevented, because the return force does not act all at once during the return displacement of the motor and the piston. Accordingly, the piston is stopped near a standby position of non-braking state before system termination. As a result, a next activation of the motor-driven disk brake system can be conducted promptly.

Motor-driven disk brake system and control device for the motor-driven disk brake system

An electric braking apparatus which first moves a piston in a detaching direction or passes a current to move the piston in the detaching direction in order to detect a pad contacting position. Furthermore, while the piston moves in the detaching direction, pad non-contact judgment is performed. After a pad non-contact state is confirmed, the piston is moved in a pressing direction to detect the pad contacting position. When the piston does not move in the detaching direction, it is judged that a parking brake has an ON-state, and it is waited until a host system instructs parking brake release.

Electric braking apparatus and vehicle having thereof

An electric disk brake that prevents uneven abrasion of a disk rotor when the brake is not in operation. Rotation of an electric motor is slowed down by a differential speed reducing mechanism, and is converted to linear motion of a piston by a ball ramp mechanism. When the brake is not in operation, the piston is retracted by reverse rotation of the electric motor so that a predetermined pad clearance is maintained. When the brake is not in operation, a pad-retracting-control electric current is supplied to the electric motor so that the piston is biased backward while being maintained in one position. When the brake is not in operation, contact of the disk rotor with the brake pads due to runout of the disk rotor triggers smooth retracting of the piston, thereby preventing uneven abrasion of the disk rotor.

Electric disk brake

A motor-driven brake system includes a brake body for enabling brake pads to be pressed against a disk rotor attached to a member which supports a wheel of a vehicle, the brake pads being adapted to be driven by an electric device; a pressing-force maintaining mechanism for maintaining the pressing force generated by the brake body; a pressing-force detecting device adapted to detect the pressing force generated by the brake body; and a control device for controlling the electric device and the pressing-force maintaining mechanism, the control device including an elapsed time measuring device adapted to measure elapsed time during a parking brake operation; and a pressing-force reduction predicting device adapted to predict, based on the elapsed time measured by the elapsed time measuring device and a value of a pressing force, a magnitude of the pressing force generated by the brake body after the elapsed time.

Motor-driven brake system

When a solenoid is operated so as to move an engaging pawl to a disengaged position, if a displacement detection device (an angular position sensor and a controller) detects that a motor rotor has not been displaced by an amount equal to or exceeding a predetermined level, that is, if the motor has not returned by an amount equal to or exceeding the predetermined level within a predetermined time period, a defect in an unlocked condition (an unlocking failure of a park braking lock mechanism) is determined. In this case, a driver is notified of the failure, so that prompt action can be taken to rectify the unlocking failure of the park braking lock mechanism.

Motor-driven disk brake system

A motor-driven disk brake is capable of functioning as a parking brake satisfactorily without degrading the brake operating feeling and impairing the function of operating as a motor-driven brake. A stator and rotor of an electric motor are provided in a caliper body floatably supported on a carrier. The rotation of the rotor is transmitted to a piston after being converted into rectilinear motion through a ball-and-ramp mechanism and an adjusting nut. The piston, together with a claw member, presses brake pads against a disk rotor. A rotation assisting device is provided between the rear end of the rotor and a motor casing. A rotary disk constituting the rotation assisting device is rotated through a wire extending from an external operating member.

Motor-driven disk brake

The present invention provides a motor driven brake system for generating and releasing braking forces by reciprocal movement of a pair of pads disposed at opposite sides of a disk having an axis. The system comprises a single electric motor, an output portion adapted to be rotated by the electric motor, a first pad pressing member for pressing a first pad against the disk a second pad pressing member for pressing a second pad against the disk, a first converting mechanism and second converting mechanism. The first converting mechanism converts rotation of the output portion to a linear motion so as to move the first pad pressing member reciprocally along the axis of the disk. The second converting mechanism converts rotation of the output portion to a linear motion so as to move the second pad pressing member reciprocally along the axis of the disk.

A motor-driven brake apparatus has a motor and a ball screw that converts rotational motion of the motor into rectilinear motion of a screw member. A position detector detects a stroke position of the screw member. A controller controls the motor on the basis of the result of detection by the position detector. The controller controls the motor so as to change the clearance between an inner pad (outer pad) and a disk according to vehicle running conditions.

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Kawasaki, Japan

Tohma Yamaguchi