Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Hitachi Astemo Ltd.

Kabushiki Kaisha Hitachi Seisakusho

Takuya Usui

Atsushi Odaira

Jun Watanabe

Daisuke Goto

Hirotaka Oikawa

Takayasu Sakashita

Masaru Sakuma

Kazumoto Sano

Toshio Takayama

Toshiyuki Ajima

Mitsuhiro Endo

Kazuhiko Nakano

Hidefumi Iwaki

Hideaki Ishii

Hiroshi Shigeta

Kunihiro Matsunaga

Daichi Nomura

Rikiya Yoshizu

Naoki Shirakawa

Satohiro Koi

Takashi Mitsugi

Daisuke Hibi

Hao Yu

Hirohumi Watanabe

A disk brake includes a brake mechanism configured to apply a braking force by advancing a piston in a cylinder portion based on driving of an electric motor to thus press inner and outer brake pads against a disk rotor, and an elastic member configured to bias the inner and outer brake pads in an axial direction of the disk rotor and in a direction away from the disk rotor. A biasing force of the elastic member is greater than sliding resistance of the piston on the cylinder portion. Due to this configuration, the disk brake can effectively prevent or reduce the drags of the inner and outer brake pads.

Disk brake

Provided is an electric brake device including one caliper including at least two electric mechanisms each configured to apply a braking force to a vehicle and to maintain the braking force. The at least two electric mechanisms are to be driven by one drive circuit output, that is, one output from one drive circuit. In this manner, for example, even when it is required to control a large number of electric mechanisms as in a case in which the electric brake device is applied to a twin-bore caliper, the number of drive circuits for driving the electric mechanisms can be reduced, thereby being capable of reducing cost.

Electric brake device

To provide a disc brake having a planetary gear reduction mechanism that may be satisfactory costly and achieve improved reliability, a planetary gear reduction mechanism of a disc brake according to the present disclosure includes a sun gear having an input gear portion to which rotation from a motor is transmitted and an output gear portion extending axially from a radial central region of the input gear portion, a plurality of planetary gears configured to mesh with the output gear portion of the sun gear, and an internal gear configured to mesh with each planetary gear, and the internal gear has a cylindrical support portion configured to rotatably support the sun gear. Accordingly, at the time of assembly, the axis of the sun gear and the axis of the internal gear may be arranged substantially concentrically, which may result in improved reliability and cost satisfaction.

Disc brake and planetary gear reduction mechanism

An electric brake apparatus includes an electronic control unit (ECU) configured to move a power piston to cause a braking hydraulic pressure to be generated in a master cylinder by controlling an electric motor of an electric actuator based on an operation on a brake pedal (an input member position). A characteristic update processing portion of the ECU is configured to update, based on an operation amount of the brake pedal, characteristic data indicating a relationship between a hydraulic value transmitted from the ECU via a vehicle data bus and a movement amount of the power piston controlled based on the input member position, and store the updated characteristic data. The ECU is configured to control the electric actuator based on the updated characteristic data when an automatic brake instruction is input.

Electric brake apparatus

An electric motor is controlled according to the back and forth movement of an input rod, which is caused by brake pedal operation; a primary piston is propelled to generate hydraulic brake pressure in a master cylinder; and the hydraulic brake pressure is fed back to the input rod through an input piston. The input piston is resiliently held by springs with respect to the primary piston. A jump-in clearance is created between the input piston and the input rod by a rearward spring. At the initial stage of braking, hydraulic brake pressure is not transmitted to the input rod due to the jump-in clearance, which provides jump-in characteristics. The jump-in clearance can be set, regardless of the amount of a relative displacement between the primary piston and the input piston, so that the range of adjustment for regenerative braking can be set larger than the jump-in clearance.

Electric booster

An electric booster includes a housing having one end including a coupling surface where the housing is coupled to a master cylinder, and the other end including an attachment surface where the housing is attached to a vehicle. A controller includes a flat plate-like control board, and the control board is disposed so as to be positioned between a first plane including the attachment surface of the housing where the housing is attached to the vehicle, and a second plane including the coupling surface of the housing where the housing is coupled to the master cylinder.

In normal braking, the operation of an electric motor is controlled according to the amount of operation of a brake pedal to drive a pressing member through a belt drive mechanism and a ball-screw mechanism, thereby pressing a piston to generate a fluid pressure in a master cylinder to obtain a braking force. A predetermined reaction force is applied to the brake pedal by a reaction force spring of a stroke simulator, and a gap is maintained between the pressing member and a movable member, thereby eliminating an uncomfortable feeling in a brake operation caused by fluid pressure variations in the master cylinder. When the electric motor fails, the movable member abuts against the pressing member and directly presses the piston to maintain the braking function. The rear end of the pressing member is inserted into a guide member and the reaction force spring to reduce the axial size.

Electric motor-driven booster

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.

A ball-and-ramp mechanism of a thrust generator includes a rotary ramp member and a rectilinear ramp member, each having a plurality of sloped grooves sloped along a circumferential direction and having an arcuate diametrical cross-section, and a spherical member interposed between the sloped grooves of the ramp members to transmit force from the rotary ramp member to the rectilinear ramp member. Each of the sloped grooves has regions varying in the curvature radius of the diametrical cross-section in a track area where the spherical member contacts the sloped groove. Accordingly, it is possible to improve the durability of the rotary ramp member and the rectilinear ramp member.

Thrust generator and disk brake

In an electric brake of the present invention, a plunger of an actuator is connected through a pin to a pivot arm to which an engaging pawl engageable with a tooth portion of a ratchet is pivotably attached. A lower surface (a force-receiving portion) of the pin is adapted to receive an upward force which is applied by a tool inserted through a bolt hole threadably engaged with a watertight bolt. When the parking brake is operated (the engaging pawl is engaged with the tooth portion of the ratchet), if supply of current to the coil becomes impossible, the pin is moved upward by means of the tool, to thereby separate the engaging pawl from the tooth portion. Therefore, an emergency action to release the parking brake can be manually conducted.

Electric brake

In the normal condition, a braking force is generated by directly supplying to a disk brake a fluid pressure generated in a master cylinder in response to an operation of a brake pedal. In addition, a braking force can be generated by supplying a fluid pressure to the disk brake by actuating a hydraulic pump motor by a controller. When a knock-back occurs due to, for example, rapid turning of a vehicle, a piston is allowed to be displaced backward so that uneven wear of a brake pad and a disk rotor can be prevented. After that, when a cause for the knock-back is eliminated, the piston is caused to move forward and a pad clearance is adjusted by actuating the pump motor by the controller so that deterioration of the responsiveness can be prevented.

Brake apparatus

There is provided an electric disk brake including a caliper and a lock mechanism wherein the lock mechanism shifts with a pad pressing member, and is composed of: a shifting member provided with a plurality of claws with a predetermined pitch in a shifting direction; an engaging member provided with an engaging portion which is engageable with the claws of the shifting member; an actuator driving the engaging member in a direction that the engaging portion engages with the claws of the shifting member; and an energizing means normally energizing the engaging member in a direction that the engaging portion is detached from the claws of the shifting member, and the engaging portion is engaged with the claws provided on one-side surface of the shifting member when being locked while the engaging portion is positioned on the other-side surface of the shifting member when being unlocked.

Electric disk brake and lock mechanism

An electric disk brake is capable of determining an abnormality of a parking brake mechanism while the parking brake mechanism is in operation. A brake force is generated in the following manner. A rotation of an electric motor is slowed down by a differential speed reducing mechanism, and is converted into a linear motion by a ball ramp mechanism so as to advance a piston, which then presses a brake pad against a disk rotor to generate a brake force. A parking brake mechanism can lock a rotation of a rotor of the electric motor and maintain a braked state by rotating an engagement pawl through a plunger of a solenoid and causing the engagement pawl to be engaged with a ratchet wheel coupled to the rotor of the electric motor. A play is provided at a coupling portion of the engagement pawl and the plunger. The play enables the plunger to move within the range of the play while the engagement pawl is engaged with the ratchet wheel, thereby enabling the determination of whether the parking brake mechanism operates normally or abnormally based on whether the plunger moves or not upon application of an electric current to the solenoid while the parking brake mechanism is in an actuated state.

Electric disk brake

The present invention provides an electric disk brake which enables an operation for wiring the harness to be easily conducted without the risk of lowering production efficiency. A caliper body-side connectorwhich, together with a harness-side connectorof a harness, forms a connector, is provided in a caliper body. In the caliper body-side connector, first to fourth lead-out terminalstoconnected to an electric portion for an electric motor are arranged in this order from a first side portiontowards a third side portionof a cover. In the harness-side connector, a first set of first to fourth harness-side terminals and a second set of first to fourth harness-side terminals independently connected to the first to fourth lead-out terminalstoare arranged in reverse order. When an electric disk brakeis used for each of the left rear wheel and the right rear wheel, one of the first set of first to fourth harness-side terminals and the second set of first to fourth harness-side terminals is used for the left rear wheel while the other is used for the right rear wheel, and the first to fourth lead-out terminals and the first to fourth harness-side terminals are connected. The harnessesextend in the same direction relative to the vehicle, thus ensuring ease of operation for wiring the harnesses

Growing community of inventors

Yokohama, Japan

Takuya Usui