Abstract: 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.

Abstract: 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.

Abstract: A brake operation sensor detects a position of an input member. An angle sensor detects a position of a power piston. An ECU drives and controls an electric motor based on a relative position between the input member and the power piston. Then, the input member and the power piston are subjected to a mechanical limitation on a relative displacement therebetween due to abutment with each other at a step. The ECU advances/retracts the power piston independently of the movement of the input member, and determines the abutment state between the input member and the power piston under the mechanical limitation based on the detected relative position. Then, the ECU corrects the relative position between the input member and the power piston based on this determination to control the electric motor.

Abstract: Provided is an electric brake apparatus capable of accurately generating a desired braking hydraulic pressure. An ECU moves a power piston to cause a braking hydraulic pressure to be generated in a master cylinder by controlling an electric motor 37 of an electric actuator based on an operation on a brake pedal (an input member position). A characteristic correction processing portion of the ECU corrects, based on an operation amount of the brake pedal, characteristic data indicating a relationship between a hydraulic value transmitted from an ECU via a vehicle data bus and a movement amount of the power piston controlled based on the input member position, and stores it. The ECU controls the electric actuator based on the corrected characteristic data when an automatic brake instruction is input.

Abstract: 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.

Abstract: 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 resiliency 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.

Abstract: The present invention controls an electric motor according to a stroke that an input rod performs in response to an operation performed on a brake pedal, and thrusts a primary piston, thereby generating a brake hydraulic pressure in a master cylinder. The brake hydraulic pressure is fed back to the input rod via an input piston and an input plunger. The present invention applies a sliding resistance against the stroke of the input rod by pressing a frictional member of a resistance force applying mechanism against a tapering sliding portion of the input rod with the aid of a spring force of a spring member. A taper angle of the sliding portion allows the sliding resistance to change at a varying ratio according to a position of the input rod, which can lead to stable application of a desired sliding resistance.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An electric motor is controlled according to an operation of a brake pedal connected to an input rod to drive a ball-screw mechanism through a transmission mechanism, thereby propelling a primary piston and a subpiston to generate brake hydraulic pressure in a master cylinder. The brake hydraulic pressure in the master cylinder is received with an input piston and transmitted to the brake pedal through a plunger rod and the input rod. The input rod and the plunger rod are tiltably connected, through a ball joint, and the plunger rod is axially slidably guided by a guide part of a rear cover. Thus, a lateral force acting on the primary piston or the subpiston is reduced to prevent an increase in sliding resistance and degradation of sealing performance.

Abstract: 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.

Abstract: 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.

Abstract: The present invention provides an electric brake apparatus capable of maintaining predetermined control accuracy despite wear of a brake pad and other changes over time. The 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 predetermined control accuracy despite wear of the brake pad and other changes over time.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In an electric booster according to one embodiment of the present invention, a brake pedal is connected to a sun gear of a differential transmission mechanism corresponding to a planetary gear mechanism. An electric motor is connected to a ring gear, and an output rod is connected to a planetary carrier, and the output rod is connected to a piston of a master cylinder. When the brake pedal is operated to rotate the sun gear, planetary pinions rotate and revolve around the sun gear. As a result, the planetary carrier rotates to move the output rod forward to push the piston. As a result, a hydraulic pressure is generated in the master cylinder. At this time, the electric motor is controlled according to the rotation of the sun gear to rotate the ring gear so that the ring gear follows the sun gear. In this manner, a servo force of the electric motor is applied to the rotation of the planetary carrier.

Abstract: 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.