A piston has a piston main body including an aluminum alloy, and a covering layer formed on the outer surface of the piston main body, and the covering layer has a first plating layer including an iron-phosphorous alloy, and a second plating layer including a nickel-phosphorous alloy formed on the first plating layer.

Disclosed herein an electric parking brake (EPB) that is controlled by an electrical signal and generates a parking braking force includes a caliper housing including a cylinder and a piston slidably provided in the cylinder; and an actuator installed in the cylinder to press and release the piston; wherein the actuator comprises a linear motor installed in the cylinder and having a moving member that moves linearly according to an electrical signal, and a pressing portion that is press-fitted to the moving member to move together with the moving member and presses selectively the piston.

A pressure-medium-actuated brake cylinder of a rail vehicle has a housing, a translationally movable brake piston rod extending through a bore in a housing base, a guide ring which is received in the bore, encloses the brake piston rod and is intended for guiding the brake piston rod in the bore, and at least one sealing ring which is received in the bore, encloses the brake piston rod and is intended for sealing an interior of the housing with respect to a space outside the housing, wherein the guide ring and the at least one sealing ring are designed as a guide and sealing ring combined to form a structural unit.

A piston boot has an annular fixing part that is formed on one end side of a stretchable part and abuts against an inner peripheral side of the cylinder. An outer peripheral surface of the annular fixing part is provided with a first region that abuts against an inner peripheral surface of the cylinder and a second region that is disposed closer to a bottom side of the cylinder than the first region in a piston axial direction. The outer diameter of the first region is larger than the inner diameter of the region of the inner peripheral surface of the cylinder that faces the second region.

An electronic parking brake system including: an electronic parking brake (EPB) including a piston that moves by a hydraulic pressure to press brake pads onto a brake disc, a cylinder in which the piston is provided movably forward and backward, and an EPB actuator that moves the piston by a motor to press the brake pads onto the brake disc; a pressure sensor configured to detect a hydraulic pressure of the cylinder; an electronic stability control (ESC) actuator configured to generate and supply a hydraulic pressure to the cylinder; and a controller configured to control the EPB actuator and the ESC actuator, wherein the controller is configured to detect an actual hydraulic pressure of the cylinder through the pressure sensor in an EPB disengagement, and when the detected actual hydraulic pressure is higher than a required hydraulic pressure, control the EPB actuator to start an EPB disengagement control.

The present invention addresses the problem of providing a disc brake device for which sliding at the boundary surface between a piston and a piston seal is suppressed, and dragging is reduced. The present invention is provided with a cylinder, a piston housed in the cylinder, an inner brake pad opposing a disc rotor, an inner circumferential groove formed in a cylinder inner circumference, and a piston seal that is provided in the inner circumferential groove and contacts the piston. The inner circumferential groove is provided with a wall, a wall on the opposite side from the wall, a bottom wall connecting the wall and the wall, and a curved surface expanding the inner circumferential groove at the wall. The bottom wall is formed such that the distance to the piston gradually increases from the wall toward the wall. The curved surface is provided with a curvature starting point on the side closer to the piston seal and a curvature endpoint on the opposite side from the curvature starting point with the curved surface therebetween, and the curvature endpoint is positioned farther outside than the cylinder inner circumference.

Disclosed is an electronic parking brake system includes: an electronic parking brake having an electric motor and a hydraulic cylinder; an ESC actuator configured to generate and supply hydraulic pressure to the hydraulic cylinder; and a controller configured to control the electric motor and the ESC actuator. The controller determines whether or not the electronic parking brake is normally releasable based on the temperature of the electronic parking brake when parking is released, and controls the electric motor to supply hydraulic pressure to the hydraulic cylinder via the ESC actuator and start parking release control when normal release is not possible.

A brake cylinder with a cylinder body having a first flange extending radially therefrom to form a radial edge with a bevel and a non-pressure head having a second flange extending radially therefrom, wherein the second flange is spaced apart from the first flange to define a first gap and includes an angled portion that extends over the bevel of the first flange to define a second gap in communication with the first gap. The two flanges form a gap in communication with the interior of the brake cylinder that extends outwardly to a V-shaped gap between the bevel of the first flange and the angled portion of the second flange to define a brake cylinder vent. The vent may be limited to four predetermined locations spaced equidistantly about the brake cylinder or the vent may extend circumferentially about the brake cylinder.

In an opposed-piston disc brake caliper, a pair of reinforcement bridge portions, which are inclined relative to an axial direction, are provided on outside of a rotor in a radial direction of the rotor so as to define corner opening portions in an opening portion which is defined by an inner body portion, an outer body portion, and an entry-side connection portion and an exit-side connection portion connecting the inner body portion and the outer body portion. A torque receiving portion of one of the entry-side torque receiving portion and the exit-side torque receiving portion is exposed toward an outside in the radial direction via the corner opening portions.

The invention relates to a brake actuator for an aircraft hydraulic brake, which is intended to be added into one of the cavities of a brake ring, the actuator comprising a liner (1) designed to be housed sealingly in the cavity of the ring, a piston (3) mounted to slide sealingly in the liner along an axis of sliding (X) so as to apply a braking force on friction pads when a fluid is introduced under pressure into the cavity, and having a determined operational travel, a wear compensation device (10) which defines a position to which the piston retreats into the liner by means of a mobile stop (11) that can be moved forward by the piston as a braking force is applied, and an elastic return member (16) returning the piston towards the retracted position bearing against the mobile stop. According to the invention, the mobile stop is reduced to a friction member rubbing against the liner, such that one of the faces of the friction member serves as a stop defining the retracted position of the piston, and the other of the faces serves as a support for the elastic return member, the elastic member having, when compressed, a sufficient increase in force in order to be able to push back the mobile stop in the event that the piston is not in contact with the friction pads while its operational travel is already exhausted.