Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Tokico, Ltd.

Kabushiki Kaisha Hitachi Seisakusho

Hirotaka Oikawa

Kenichiro Matsubara

Toshio Takayama

Daisuke Goto

Junichi Ikeda

Hiroki Takeda

Kimio Nishino

Takuya Usui

Tohma Yamaguchi

Takayasu Sakashita

Shinya Imura

Jun Watanabe

Atsushi Yokoyama

Satoru Kuragaki

Kenji Hiraku

Takahiro Ito

Wataru Yokoyama

Mitsuhide Sasaki

Masaru Sakuma

Takayuki Ohno

Takuya Obata

Kentarou Ueno

Yoshinari Kawahara

Tatsuro Kobune

Youichi Kumemura

Tomoyuki Kotake

A brake apparatus comprising: a caliper having a piston configured to move a brake pad to be pressed on a disc rotor rotating with a wheel; a thrust retaining mechanism located in the caliper to thrust the piston and maintain braking force exerted by the thrust piston; an electric motor mounted on the caliper to operate the thrust retaining mechanism; and a controller configured to apply electric current to the electric motor in response to an application command or a release command, thereby perform control according to the commands, wherein the controller, upon receiving a release command, configured to operate the electric motor to reduce braking force exerted by the piston by performing current maintenance control which continuously applies electric current to the electric motor and switching control which successively switches between a larger and a smaller amount of electric current applied to the electric motor.

Brake apparatus

A disk brake apparatus includes a piston thrust mechanism disposed in a caliper and including a thrust member configured to thrust a piston by an electric motor, and a piston holding mechanism configured to hold the thrust piston. When the piston holding mechanism release the holding of the thrust piston, the controller acquires a hydraulic pressure supplied to the caliper. If the hydraulic pressure is a predetermined value or higher, the controller determines whether a thrust force generated by the electric motor is released based on a time period from issue of an instruction to release the holding of the piston and a start of driving of the electric motor. If the hydraulic pressure is lower than the predetermined value, the controller determines whether the thrust force generated by the electric motor is released based on a change status of a current for driving the electric motor.

Disk brake apparatus

A brake system includes a brake apparatus. This brake apparatus is configured to keep a vehicle braked by an electric mechanism in response to a parking brake request signal, and brake the vehicle by supply of a hydraulic pressure from a hydraulic source in response to an operation performed on a brake pedal. The brake system further includes a controller configured to drive the electric mechanism until a target pressing force is acquired to establish a brake holding state in response to the parking brake request signal. The controller is configured to change the target pressing force according to a change in a hydraulic pressure in the brake apparatus after starting driving the electric mechanism in response to the parking brake request signal.

Brake system

There is provided a disk brake that can hold a required thrust force and maintain a stop state of a vehicle without increasing complexity in the disk brake even if the disk brake is operated in a high temperature state of a brake pad and then a temperature of the brake pad is reduced. In the disk brake, an electric motoris driven to thrust a piston, the pistonpresses the brake padagainst a disk rotor, and the pistonis held in the pressed position, the electric motoris re-driven after a predetermined time from a start of holding of the piston, and a driving condition of the electric motorafter re-driving is determined based on a change in value of a current supplied to the electric motorby the re-driving.

Disk brake

A disc brake apparatus, in which, at the time of a parking brake release operation, a control unit configured to control driving of an electric motor drives the electric motor so as to cause a piston holding mechanism to stop holding a piston, detects separation of a brake pad from a disk, and then stops driving the electric motor after driving the electric motor by a predetermined amount based on a current value of the electric motor.

Disc brake apparatus

An electric brake apparatus compares an estimated thrust force corresponding to a predetermined rotational position of an electric motor, which is calculated from an electric current/thrust force conversion function, with a reference thrust force based on a rotational position/thrust force table indicating a relationship between the rotational position of the electric motor and a thrust force of a piston to correct and update the electric current/thrust force conversion function, thereby maintaining a predetermined control accuracy despite wear of a brake pad and other changes over time.

Electric brake apparatus

Even when a rigidity table stored in a RAM at the time of a start of a brake operation does not coincide with an actual rigidity characteristic of an electric caliper which changes according to brake conditions including how often and how long a brake operation is applied, it is possible to reduce a deviation between a pressing force instruction value and a generated pressing force by updating the characteristic of the relation between a pressing force instruction value and rotational position each time an estimated thrust force value is calculated during one brake operation. It is possible to steadily keep followability to a pressing force instruction according to an actual state of the rigidity characteristic of the electric caliper, thereby ensuring generation of an appropriate brake force.

A disc brake apparatus including a disc brake having a parking brake mechanism operated by an electric motor as a drive source to mechanically hold a piston in a braking position even after the hydraulic pressure is released; and a controller for supplying a predetermined amount of hydraulic pressure from a hydraulic control unit to caliper caliper, based on a parking-brake indicating signal from a parking brake switch and for operating the parking brake mechanism. In a case in which a brake pedal is being operated when a parking-brake indicating signal is input, the parking brake mechanism is operated in a state in which a hydraulic pressure in the caliper is at a predetermined pressure, after the operation of the brake pedal is finished, so as to reduce a hydraulic pressure required for a release of a brake pedal.

A brake apparatus is provided that can make a ratio between a front wheel braking force and a rear wheel braking force that is actually generated into an arbitrary ratio. This brake apparatus includes a pedal operation detection section that detects a pedal stroke or a brake pedal force produced by a brake pedal operation; a brake caliper that is provided in each wheel of a vehicle and that generates a caliper force that is in accordance with a detection value of the pedal operation detection section; a load estimation section that estimates a load of each of the wheels; and a force generation section that, after judging that braking is performed in a state in which a load difference exists between left and right wheels of the vehicle based on a value that is estimated by the load estimation section, even if the pedal operation detection section detects a pedal stroke or a brake pedal force that is the same as for the braking at a time of judging or for braking prior to the judging, generates a caliper force that is different to the caliper force before the judgment.

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 booster according to the present invention comprises a booster piston disposed around an input piston so as to movable relative to the input piston. The booster piston and input piston also serve as a primacy piston of a tandem master cylinder. A brake fluid pressure is generated in the tandem master cylinder by an input thrust force provided from a brake pedal to the input piston and a booster thrust force provided from the electronic actuator to the booster piston. In this electric booster, a slide hole is formed through the secondary piston of the tamed master cylinder in the axial direction therefore, and a rod member is slidably disposed through the slide hole. When the fluid pressure is not increased in the primary pressure chamber, due to the fluid pressure in the secondary pressure chamber, the rod member comes to abut against the input piston, and a reactive force in the secondary pressure chamber is returned to the brake pedal.

Electrically driven brake booster and master cylinder

The invention provides an electro-mechanical brake system which can keep a stop state even if a malfunction is generated in a parking brake, and an electro-mechanical brake apparatus used for the electro-mechanical brake system. An electro-mechanical brake actuator presses a brake pad to a disc rotor so as to independently brake a braking force of each of wheels. A parking brake is constituted by a pawl portion attached to a motor of a motor driving the electro-mechanical actuator and a latch. A main controller detects a failure of the parking brake on the basis of a motor displacement at a time of reducing a motor current, and increases the pressing force in the remaining normal parking brake in the case that the parking brake failure in one wheel or more is detected.

Electro-mechanical brake system and electro-mechanical brake apparatus used therefor

An electric braking apparatus is disclosed in which a rotational movement from a motor is converted into linear movement that moves a brake piston to generate braking force. The electric brake apparatus can perform full parking brake function without sacrificing its original braking function. In operation, immediately after generation of braking force caused by rotation of the rotor () supply of electricity to the motor is turned off. After supply of electricity is turned off, however, the rotor () is restricted from returning to its original position due to an engagement with an engaging claw () via a claw wheel (), thereby keeping the barking brake remain effective. When electricity is thereafter supplied to the motor, the rotor () generates rotational torque sufficiently strong to push down the engaging claw () for disengagement, thereby releasing the parking brake.

Electric braking apparatus

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.

Motor-driven brake apparatus

The present invention relates to an improved antiskid control apparatus for vehicles. When the front wheel on either one of the right and left sides is antiskid-controlled, this apparatus detects whether the road surface is in the condition of split .mu. in which the road surface friction coefficient is different between the right and left wheels by more than the prescribed value. When the road surface is found to have a split .mu. condition, antiskid control should be implemented on the front wheel mentioned above. To control the rise in brake fluid pressure, the other front wheel must then be shifted in whatever direction facilitates control of the threshold value. In other words, even if a wheel does not attain a sufficient coefficient of surface friction, antiskid control is needed to control easily the rise in brake fluid pressure. A large side force is applied continuously to the vehicle, thereby reducing slippage and cancelling the yaw moment.

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Yokohama, Japan

Hirotaka Oikawa