Abstract: An electrically actuated booster performs displacement control such that the relative displacement relationship between an input member and an assist member is variable according to the absolute displacement of the input member. A target displacement that makes variable the relative displacement relationship between an input piston and a booster piston is set according to a detection signal from a potentiometer (86), and displacement control is performed so that the relative displacement between the two pistons becomes equal to the target displacement on the basis of a signal from a relative displacement sensor (100) that detects the relative displacement between the two pistons.

Abstract: An object of the present invention is to provide an electric booster enabling an easy connection of an ECU and a stator. An ECU casing containing boards and (ECU) is attached to the outer surface of the casing body so as to be located near a stator of an electric motor. The opening of the casing body is closed by a rear cover. A flat-portion through-hole (through-hole) is formed through the casing body. Bus bars connecting the stator and the ECU are disposed through the flat-portion through-hole. The bus bars are disposed such that one ends thereof are coupled with the stator while the other ends thereof protrude from the flat-portion through-hole. When the electric booster is assembled, since the stator and the bus bars are disposed at the casing body having the flat-portion through-hole, it is possible to easily assemble the casing body and the rear cover with the bus bars inserted through the flat-portion through-hole.

Abstract: An electrically actuated booster performs displacement control such that the relative displacement relationship between an input member and an assist member is variable according to the absolute displacement of the input member. A target displacement that makes variable the relative displacement relationship between an input piston and a booster piston is set according to a detection signal from a potentiometer (86), and displacement control is performed so that the relative displacement between the two pistons becomes equal to the target displacement on the basis of a signal from a relative displacement sensor (100) that detects the relative displacement between the two pistons.

Abstract: An electrically actuated booster performs displacement control such that the relative displacement relationship between an input member and an assist member is variable according to the absolute displacement of the input member. A target displacement that makes variable the relative displacement relationship between an input piston and a booster piston is set according to a detection signal from a potentiometer (86), and displacement control is performed so that the relative displacement between the two pistons becomes equal to the target displacement on the basis of a signal from a relative displacement sensor (100) that detects the relative displacement between the two pistons.

Abstract: An electric booster which drives an electric motor (40) in response to a movement of an input member (9) moving together with a brake pedal (B), and generates a brake hydraulic pressure in a master cylinder (10) through a ball screw mechanism (50). The electric motor (40) includes a stator (41) having a coil therein, a rotor (42) which rotates by applying current to the stator (41), and an annular motor casing (2) containing the stator (41) and the rotor (42). The ball screw mechanism (50) is fittedly disposed in the rotor (42). An opening (3b) on one axial end side of the motor casing (2) has a larger diameter than an outer diameter of the ball screw mechanism (50). In manufacturing, after the electric motor (40) alone is tested, the ball screw mechanism (50) is inserted through the opening (3b) and installed without the need of disassembling the motor casing (2).

Abstract: An object of the present invention is to provide an electric booster enabling an easy connection of an ECU and a stator. An ECU casing containing boards and (ECU) is attached to the outer surface of the casing body so as to be located near a stator of an electric motor. The opening of the casing body is closed by a rear cover. A flat-portion through-hole (through-hole) is formed through the casing body. Bus bars connecting the stator and the ECU are disposed through the flat-portion through-hole. The bus bars are disposed such that one ends thereof are coupled with the stator while the other ends thereof protrude from the flat-portion through-hole. When the electric booster is assembled, since the stator and the bus bars are disposed at the casing body having the flat-portion through-hole, it is possible to easily assemble the casing body and the rear cover with the bus bars inserted through the flat-portion through-hole.

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: The present invention relates to an electrically driven brake booster in which boost control is performed as follows; when an input piston is displaced forward by an input rod upon an operation of a brake pedal, an electric motor is operated according to the input, and a primary piston is displaced forward by a ball-screw mechanism, and then a primary and secondary pressure chamber in a master cylinder main body are pressurized. A first seal and a second seal are disposed at a seal portion between the primary piston and the input piston. A portion between the first seal and the second seal is in communication with an outside through a discharge passage. Brake fluid which leaks from the first seal is sealed off by the second seal, and is discharged to the outside through the discharge passage, whereby it becomes possible to prevent that the electric motor and the ball-screw mechanism otherwise might be corroded by the leaking brake fluid.

Abstract: An electrically actuated brake booster capable of obtaining a desired boost ratio for a given input pressure when an electric actuator is activated as a boost source, so as to ensure a desired operability of a brake pedal. The electrically actuated brake booster comprises: an input piston 22 to which an input thrust is applied through an input rod 9 that moves in coordination with operation of a brake pedal 8; and a booster piston 21 to which a booster thrust is applied by an electric actuator 40 that uses an electric motor 41 as a drive source, such that the input piston 22 and the booster piston 21 are disposed to be movable relative to each other but are normally maintained in a neutral position of relative displacement by means of springs 34. While an amount of relative displacement between the pistons 21 and 22 is determined by the potentiometer 45, the electric motor 41 is controlled to adjust the amount of relative displacement to a predetermined value.

Abstract: A disk brake with a parking brake mechanism capable of exerting a large piston thrust required for operating a parking brake, without adversely affecting operation of a service brake. A parking brake mechanism 32, which is driven by an electric motor provided outside a housing 30, is incorporated in a caliper 14 in which a piston 26 is slidably disposed in a cylinder 24. The parking brake mechanism 32 is slidably fitted via a seal member 36 into the piston 26 and provided with a nut member 37 that is prevented from rotating relative to the piston 26 by engagement of a pin 48 and a pin hole 49; and a shaft 35 that is screwed into the nut member 37. During a service brake operation, the piston 26 alone is moved by a hydraulic pressure under a small piston thrust.

Abstract: 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.

Abstract: An electrically actuated booster capable of obtaining various desired brake characteristics and improving brake feeling performs displacement control such that the relative displacement relationship between an input member and an assist member is variable according to the absolute displacement of the input member. A target displacement that makes variable the relative displacement relationship between an input piston and a booster piston is set according to a detection signal from a potentiometer (86) (input absolute displacement detecting means), and displacement control is performed so that the relative displacement between the two pistons becomes equal to the target displacement on the basis of a signal from a relative displacement sensor (100) that detects the relative displacement between the two pistons.

Abstract: An object of the present invention is to provide an electric booster and a manufacturing method thereof in which it becomes possible to conduct a test of an electric motor alone without disassembling a motor casing, thereby facilitating the manufacturing process and reducing manufacturing cost. In an electric booster which drives an electric motor 40 in response to a movement of an input member 9 moving together with a brake pedal B, and generates a brake hydraulic pressure in a master cylinder 10 through a ball screw mechanism 50, the electric motor 40 comprises a stator 41 including a coil therein, a rotor 42 which rotates by applying current to the stator 41, and an annular motor casing 2 containing the stator 41 and the rotor 42. The ball screw mechanism 50 is fittedly disposed in the rotor 42. An opening 3b on one axial end side of the motor casing 2 has a larger diameter than an outer diameter of the ball screw mechanism 50.

Abstract: The present invention relates to an electrically driven brake booster in which boost control is performed as follows; when an input piston is displaced forward by an input rod upon an operation of a brake pedal, an electric motor is operated according to the input, and a primary piston is displaced forward by a ball-screw mechanism, and then a primary and secondary pressure chamber in a master cylinder main body are pressurized. A first seal and a second seal are disposed at a seal portion between the primary piston and the input piston. A portion between the first seal and the second seal is in communication with an outside through a discharge passage. Brake fluid which leaks from the first seal is sealed off by the second seal, and is discharged to the outside through the discharge passage, whereby it becomes possible to prevent that the electric motor and the ball-screw mechanism otherwise might be corroded by the leaking brake fluid.

Abstract: An electrically actuated brake booster capable of obtaining a desired boost ratio for a given input pressure when an electric actuator is activated as a boost source, so as to ensure a desired operability of a brake pedal. The electrically actuated brake booster comprises: an input piston 22 to which an input thrust is applied through an input rod 9 that moves in coordination with operation of a brake pedal 8; and a booster piston 21 to which a booster thrust is applied by an electric actuator 40 that uses an electric motor 41 as a drive source, such that the input piston 22 and the booster piston 21 are disposed to be movable relative to each other but are normally maintained in a neutral position of relative displacement by means of springs 34. While an amount of relative displacement between the pistons 21 and 22 is determined by the potentiometer 45, the electric motor 41 is controlled to adjust the amount of relative displacement to a predetermined value.

Abstract: An electrically actuated brake booster capable of obtaining a desired boost ratio for a given input pressure when an electric actuator is activated as a boost source, so as to ensure a desired operability of a brake pedal. The electrically actuated brake booster comprises: an input piston 22 to which an input thrust is applied through an input rod 9 that moves in coordination with operation of a brake pedal 8; and a booster piston 21 to which a booster thrust is applied by an electric actuator 40 that uses an electric motor 41 as a drive source, such that the input piston 22 and the booster piston 21 are disposed to be movable relative to each other but are normally maintained in a neutral position of relative displacement by means of springs 34. While an amount of relative displacement between the pistons 21 and 22 is determined by the potentiometer 45, the electric motor 41 is controlled to adjust the amount of relative displacement to a predetermined value.

Abstract: An electrically actuated brake booster capable of obtaining a desired boost ratio for a given input pressure when an electric actuator is activated as a boost source, so as to ensure a desired operability of a brake pedal. The electrically actuated brake booster comprises: an input piston 22 to which an input thrust is applied through an input rod 9 that moves in coordination with operation of a brake pedal 8; and a booster piston 21 to which a booster thrust is applied by an electric actuator 40 that uses an electric motor 41 as a drive source, such that the input piston 22 and the booster piston 21 are disposed to be movable relative to each other but are normally maintained in a neutral position of relative displacement by means of springs 34. While an amount of relative displacement between the pistons 21 and 22 is determined by the potentiometer 45, the electric motor 41 is controlled to adjust the amount of relative displacement to a predetermined value.

Abstract: A disk brake with a parking brake mechanism capable of exerting a large piston thrust required for operating a parking brake, without adversely affecting operation of a service brake. A parking brake mechanism 32, which is driven by an electric motor provided outside a housing 30, is incorporated in a caliper 14 in which a piston 26 is slidably disposed in a cylinder 24. The parking brake mechanism 32 is slidably fitted via a seal member 36 into the piston 26 and provided with a nut member 37 that is prevented from rotating relative to the piston 26 by engagement of a pin 48 and a pin hole 49; and a shaft 35 that is screwed into the nut member 37. During a service brake operation, the piston 26 alone is moved by a hydraulic pressure under a small piston thrust.

Abstract: The present invention provides a motor-driven brake system comprising: 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, to thereby brake the wheel under a pressing force, the brake pads being adapted to be driven by means of an electric device; a pressing-force maintaining mechanism for maintaining the pressing force generated by the brake body, to thereby effect a parking brake operation; pressing-force detecting means 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 comprising: elapsed time measuring means adapted to measure elapsed time during the parking brake operation by the pressing-force maintaining mechanism; and pressing-force reduction predicting means adapted to predict, based on the elapsed time measured by the elapsed time measuring means and a value of the pressing force as dete

Abstract: In an electrically actuatable disc brake, rotation of a rotor of an electric motor is reduced by means of a differential reduction mechanism. A ball ramp mechanism is operated to press brake pads against a disc rotor to generate a braking force. In the differential reduction mechanism, when an eccentric shaft of the rotor is subjected to eccentric rotation, an external gear member having external input teeth meshing with a fixed ring gear performs an orbital motion while rotating on a center axis of the gear member, whereby a set of external output teeth of the gear member performs an orbital motion while rotating on the center axis to operate a ring gear integrally formed with a rotary disc of the ball ramp mechanism. A high reduction ratio can be easily obtained. The differential reduction mechanism can be easily formed and imparted with sufficient strength.