Disclosed is an actuator of an electronic brake system including: a motor having a stator and a rotor for generating a rotational force by an electrical signal, the rotor having an accommodating space therein; a power conversion unit disposed in the accommodating space, and including a spindle rotated by a rotational force of the rotor and a nut coupled to the spindle to be linearly moved by rotation of the spindle; a piston coupled to move with the nut; and a sleeve coupled to one end of the rotor by a bearing so that the rotor is relatively rotatable and having an inner space communicating with the accommodating space and accommodating the piston so as to be able to move forward and backward.

Disclosed is an actuator of an electronic brake system including: a drive unit generating a power and including a motor having a stator and a rotor; a piston unit operated by the drive unit and including a piston reciprocating in a bore chamber provided in a piston housing to contain a fluid; a power transmission unit having one end coupled to the rotor and the other end coupled to the piston to convert a rotational motion of the rotor into a linear motion of the piston; a sensing magnet coupled to the power transmission unit to rotate along the motor; and a motor position sensor disposed coaxially with and spaced apart from the sensing magnet to sense a position of the motor based on the rotation of the sensing magnet.

A hydraulic pressure generating device includes a base body, a master cylinder provided on the base body and configured to generate a brake hydraulic pressure by a first piston connected to a brake operating element, a housing attached to the base body, a control board contained in the housing, a stroke sensor configured to detect an amount of movement of the first piston; and a detection object member which is detected by the stroke sensor. The housing has a facing wall portion provided so as to face the base body. The stroke sensor is provided inside the housing on the opposite side of the facing wall portion to the base body, and is electrically connected to the control board.

One embodiment provides a hydraulic pressure generation apparatus including: a base body; a motor; a reservoir tank; a master cylinder which generates a brake hydraulic pressure by a brake manipulator; and a slave cylinder which generates a brake hydraulic pressure the motor. The base body includes: a first cylinder hole which is a bottomed cylinder hole, and in which the first piston is inserted; a second cylinder hole which is a bottomed cylinder hole, and in which the second piston is inserted; and a supply passage which leads from the reservoir tank to a hydraulic chamber of the slave cylinder. The supply passage is provided with a check valve which permits only inflow of brake fluid from the reservoir tank to a side of the slave cylinder, near a brake fluid discharge port of the second cylinder hole.

A braking device for a hydraulic motor vehicle brake system, with an energy-store-free, electronically controlled electric-motor-driven on-demand braking force booster and with a master brake cylinder, in which, for the purpose of reducing the foot force on the brake pedal in the fall-back level, the braking pressure in the pressure chamber is built up stepwise and at least one active surface involved in generating brake pressure is switchable so as to be hydraulically ineffective.

An object of the present invention is to provide a brake apparatus that allows low-cost attachment of a stroke sensor that detects a stroke amount of a brake pedal. The brake apparatus is configured in such a manner that the stroke sensor that detects an amount of an axial stroke of a piston is disposed between one side surface of a master cylinder housing and one side surface of a valve housing, and an output of the stroke sensor is transmitted via a through-hole formed on the valve housing when being transmitted to a control unit attached to an opposite side surface-side of the valve housing.

A master cylinder and an electronic brake system including the same are disclosed. The electronic brake system includes a main hydraulic-pressure supply device to generate hydraulic pressure by sensing displacement of a brake pedal and a sub hydraulic-pressure supply unit to supply hydraulic pressure to at least one wheel cylinder during an abnormal operation of the main hydraulic-pressure supply device. The master cylinder includes a first piston disposed in a bore of a cylinder body so as to be directly pressurized by the brake pedal, a first hydraulic chamber pressurized by the first piston to discharge hydraulic pressure, a second piston indirectly pressurized by the first piston, and a second hydraulic chamber pressurized by the second piston to discharge hydraulic pressure. The second hydraulic chamber includes a slippage prevention means connected to the sub hydraulic-pressure supply unit so as to prevent the second piston from moving toward the first piston by the hydraulic pressure received from the sub hydraulic-pressure supply unit.

Provided are a brake apparatus, a brake system, and a master cylinder that can accurately detect a movement amount of a piston while reducing manufacturing cost. A brake apparatus includes a master cylinder housing including a cylinder therein, a piston provided inside the cylinder and movable in a direction of an axial line of the cylinder, a magnet provided, inside the cylinder, partially in a circumferential direction of the piston, which is a direction around the axial line, and configured to be displaced according to a movement of the piston, a detection portion provided on the master cylinder housing and configured to detect a movement amount of the piston, and a rotation restriction mechanism provided inside the cylinder and configured to restrict a movement of the magnet in the circumferential direction.

A master cylinder for a hydraulic brake comprises a compensating chamber, a cylinder in which a piston is movably disposed, a pressure chamber disposed in the cylinder and connected to the compensating chamber through at least one connecting opening, and a gasket for interrupting the connection between the pressure chamber and the compensating chamber. The gasket seals the compensating chamber and the pressure chamber against the environment.

A hydraulic brake device includes (a) a master fluid passage for supplying a working fluid from a master cylinder to a wheel brake, (b) a master shut-off valve provided in the master fluid passage, (c) a return fluid passage, (d) a return passage opening valve provided in the return fluid passage, (e) an electromagnetic control valve provided in the return fluid passage and configured to control a flow of the working fluid or to allow a flow of the working fluid without controlling, and (f) a stroke simulator having first and second fluid chambers defined by a partition member, the first fluid chamber being connected to the master fluid passage between the master shut-off valve and the master cylinder, the second fluid chamber being connected to the return fluid passage on one on opposite sides of the return passage opening valve that is nearer to the wheel brake.