Abstract: Provided is a disc brake including: a piston, which has a bottomed cylindrical shape, and is configured to press inner and outer brake pads against a disc rotor; a nut member (thrust member) configured to thrust the piston through rotation of a spindle driven by an electric motor; a rotation stopping member configured to restrict rotation of the nut member relative to the piston; a flat surface portion, which is formed on an inner side of the piston, and is configured to restrict rotation of the rotation stopping member and stop the rotation stopping member through engagement; and a fixing member configured to restrict movement of the rotation stopping member in an axial direction relative to the piston. This configuration allows easy manufacture of the nut member.

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: 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: A disc brake including a piston driving mechanism. The piston driving mechanism includes an input member extended in a cylinder in a protruding direction of a piston, including a threaded portion formed on a circumferential surface of the input member, and configured to be rotated with transmission of torque from an electric motor; a tubular rotation linear motion member including an engaging threaded portion that is engaged with the threaded portion of the input member, and configured to move in an axial direction of the cylinder by rotation of the input member to transmit a torque of the electric motor to the piston; a tubular support member supported on a caliper main body to be not rotatable and placed on an outer side in a radial direction with respect to the rotation linear motion member; and a rolling element placed between the support member and the rotation linear motion member.

Abstract: A disc brake including a piston driving mechanism. The piston driving mechanism includes an input member extended in a cylinder in a protruding direction of a piston, including a threaded portion formed on a circumferential surface of the input member, and configured to be rotated with transmission of torque from an electric motor; a tubular rotation linear motion member including an engaging threaded portion that is engaged with the threaded portion of the input member, and configured to move in an axial direction of the cylinder by rotation of the input member to transmit a torque of the electric motor to the piston; a tubular support member supported on a caliper main body to be not rotatable and placed on an outer side in a radial direction with respect to the rotation linear motion member; and a rolling element placed between the support member and the rotation linear motion member.

Abstract: An object of the present invention is to obtain a brake system that can generate appropriate braking force without influence of temperature. A brake system includes: a piston that presses pressing members; a motor that moves the piston; a current detection unit that detects current flowing in the motor; a storage unit that stores a correspondence relation between idle running current and motor stopping current; a motor stopping current setting unit that sets the motor stopping current using the storage unit and the idle running current; and a control unit that stops to supply the current to the motor when the current flowing in the motor reaches the motor stopping current. The correspondence relation is set so that the rate of change of the motor stopping current relative to the idle running current becomes smaller when the idle running current is small than that when it is large.

Abstract: 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.

Abstract: A rotary-to-linear conversion mechanism includes a rotation transmission member, a shaft member threadedly fitted to the rotation transmission member so that a rotation and linear motion of the shaft member are enabled, and a ball-and-ramp mechanism threadedly fitted to the shaft member, which is configured to apply a thrust in the axial direction to a piston through the rotation of the shaft member. The shaft member includes a first thread formed on one end side thereof, and a second thread formed on the other end side thereof. A rotation friction torque of the first thread is larger than a rotation friction torque of the second thread.

Abstract: A disk brake (1) including a connector portion (35) provided at a housing (30). The connector portion (35) includes supply terminals (131) for supplying power to a motor (32). The supply terminals (131) of the connector portion (35) and motor terminals (32C) of the motor (32) are connected to each other via bus bars (130) made of metallic plate. Further, the bus bars (130) are held in a loosely fitted state on another-side surface (138B) of a plate-like portion (138) of a support member (135) attached to the housing (30).

Abstract: 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.

Abstract: Upon a start of a release for releasing a braking state of a parking bake in a process of step 2, a control unit (13) performs hydraulic maintaining control by an ESC (11) in a subsequent step, step 3. As a result, a hydraulic pressure in a cylinder portion (46) increases according to a retraction of a piston (49) of a disk brake (41). If the control unit (13) determines in step 4 that the release of the parking brake has been completed, in step 5, the control unit (13) releases the hydraulic maintaining control by the ESC (11). The hydraulic pressure is temporarily increased in the cylinder portion (46) of the disk brake (41), thereby increasing an elastic deformation amount of a piston seal (56) to succeed in acquiring a sufficient rollback function.

Abstract: An object of the present invention is to obtain a brake system that can generate appropriate braking force without influence of temperature. A brake system includes: a piston that presses pressing members; a motor that moves the piston; a current detection unit that detects current flowing in the motor; a storage unit that stores a correspondence relation between idle running current and motor stopping current; a motor stopping current setting unit that sets the motor stopping current using the storage unit and the idle running current; and a control unit that stops to supply the current to the motor when the current flowing in the motor reaches the motor stopping current. The correspondence relation is set so that the rate of change of the motor stopping current relative to the idle running current becomes smaller when the idle running current is small than that when it is large.

Abstract: A rotary-to-linear conversion mechanism includes a rotation transmission member, a shaft member threadedly fitted to the rotation transmission member so that a rotation and linear motion of the shaft member are enabled, and a ball-and-ramp mechanism threadedly fitted to the shaft member, which is configured to apply a thrust in the axial direction to a piston through the rotation of the shaft member. The shaft member includes a first thread formed on one end side thereof, and a second thread formed on the other end side thereof. A rotation friction torque of the first thread is larger than a rotation friction torque of the second thread.

Abstract: A disk brake including a simplified structure for retaining the braking force of a parking brake. The disk brake is equipped with a piston holding mechanism having a ball-and-ramp mechanism in which balls are moved by rotation transmitted from a motor, causing a rotary-rectilinear ramp to press a piston. The rotary-rectilinear ramp has an external thread engaged with an internal thread formed on a base nut that is immovable in a rotor axis direction relative to a caliper body. The external thread, when a force is applied thereto from the piston in the rotor axis direction, can retain the position of the rotary-rectilinear ramp in the rotor axis direction. Thus, the structure for retaining the braking force of the parking brake can be simplified to improve production efficiency.

Abstract: 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.

Abstract: Upon a start of a release for releasing a braking state of a parking bake in a process of step 2, a control unit (13) performs hydraulic maintaining control by an ESC (11) in a subsequent step, step 3. As a result, a hydraulic pressure in a cylinder portion (46) increases according to a retraction of a piston (49) of a disk brake (41). If the control unit (13) determines in step 4 that the release of the parking brake has been completed, in step 5, the control unit (13) releases the hydraulic maintaining control by the ESC (11). The hydraulic pressure is temporarily increased in the cylinder portion (46) of the disk brake (41), thereby increasing an elastic deformation amount of a piston seal (56) to succeed in acquiring a sufficient rollback function.

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: Provided is a disc brake with high reliability. In a disc brake (1), pins (60) press-fitted to a carrier (58) are inserted through hole portions (56B) of respective planet gears (56) in a freely rotatable and axially movable manner. Further, axial movement of the carrier (58) is allowed by an amount corresponding to a length of a clearance (37). As a result, when a rotary-to-linear ramp (65) advances during actuation of a parking brake, the carrier (58) and the pins (60) advance together with the rotary-to-linear ramp (65). Thus, actuation efficiency becomes excellent and durability is enhanced.

Abstract: 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.

Abstract: An object of the present invention is to provide a highly reliable disk brake. In a disk brake 1 according to the present invention, a connector portion 35 is provided at a housing 30. The connector portion 35 includes supply terminals 131 for supplying power to a motor 32. The supply terminals 131 of the connector portion 35 and motor terminals 32C of the motor 32 are connected to each other via bus bars 130 made of metallic plate. Further, the bus bars 130 are held in a loosely fitted state on another-side surface 138B of a plate-like portion 138 of a support member 135 attached to the housing 30.