A spring brake actuator (1) for a vehicle, in particular a parking or emergency brake actuator, for use in a commercial vehicle, includes a cylinder housing (2) having a cylinder housing base (5) and a spring seat (7) on the base, a spring brake piston (9) located in the cylinder housing (5) for applying a braking force, and a compression spring (11) arranged between the spring seat (7) and the spring brake piston (9). The cylinder housing (2) is divided into a spring chamber (12) and a pressure chamber (14), the compression spring (11) being arranged in the spring chamber (12) and the pressure chamber (14) being supplied with pressurized fluid. An elastically deformable diaphragm (16) is sealingly mounted to the cylinder housing (2), with an inner periphery (18) sealingly mounted to the spring brake piston (9) to fluid-tightly isolate the pressure chamber (14) from the spring chamber (12).

A hydraulic device comprises a base member, a piston, a seal ring, and an intermediate member. The base member includes a cylinder bore and an annular groove. The annular groove includes a first inner surface and a second inner surface. The piston is movable relative to the base member from a rest position toward an actuated position in a second direction opposite to a first direction. The piston is movable relative to the base member from the actuated position toward the rest position in the first direction. The seal ring includes a first axial surface facing in the first direction and a second axial surface facing in the second direction. The seal ring is provided in the annular groove so as to define a clearance between the first axial surface and the first inner surface. The intermediate member is provided in the clearance.

Hybrid brake piston systems, methods of making hybrid brake piston systems and methods of using hybrid brake piston systems are provided. The hybrid disk brake piston systems have load bearing metal-based pressure pads and engineered resin-based outer bodies that are assembled using seal layouts and/or grooves. The metal-based pressure pads may be made from mild steel, stainless steel or aluminum and/or are designed and configured to contact both a spindle nut and a brake pad and to carry the load whilst under electronic parking activation. The resin-based outer bodies may be made of phenolic resin and/or are designed to move under hydraulic brake activation.

Disclosed herein a drum brake for a vehicle includes a drum rotating together with a wheel of the vehicle, a pair of brake shoes generating a braking force by friction with an inner surface of the drum, and a wheel cylinder provided between one ends of the pair of brake shoes to operate the pair of brake shoes outwardly, wherein the wheel cylinder includes a pair of pistons configured to press and release the pair of brake shoes, a cylinder configured to accommodate the pair of pistons movable forward and backward, and a pair of sealing members inserted into annular recessed grooves formed on an inner surface of the cylinder, and each of the sealing members returns the pair of pistons when a pressure of the pistons is released.

A brake caliper housing and a method of checking sealing of a brake caliper housing. The brake caliper housing may include a cavity, a guide pin opening, and an internal passage. The guide pin opening may receive a guide pin that facilitates sliding movement of the brake caliper housing. The internal passage may extend from the cavity to the guide pin opening.

A rotationally symmetrical bellows has a first end ring and a second end ring with a smaller diameter, and multiple folds, which in a relaxed position each have two flanks running in opposite directions with respect to one another while forming a bend. The flanks extend approximately parallel to an axis of rotation of the bellows. The rotationally symmetrical bellows is designed such that in a relaxed position of the bellows, the second end ring is arranged at an axial distance to the first end ring.

Disclosed is a caliper brake including a carrier on which a pair of pad plates are installed to advance and retreat, a caliper housing slidably installed on the carrier and provided with a cylinder, a piston installed in the cylinder and provided to advance and retreat toward the pad plates by braking hydraulic pressure, a seal groove formed to be annularly recessed into an inner surface of the cylinder, and a ring-shaped seal member in close contact with an outer surface of the piston and accommodated in the seal groove, wherein the seal groove includes a bottom surface with which an outer circumferential surface of the seal member is in close contact, a first surface facing a front surface of the seal member, a second surface facing a rear surface of the seal member, and a bent surface in contact with the bottom surface and the second surface and provided in an arc shape.

A helical gearing for driving an adjusting element, which may be an actuator or a piston of a piston-cylinder unit, is driven by an electric motor. The adjusting element may be moved along an axis. The drive apparatus has a rotor, or a translator rotatably mounted in a housing by a bearing and fixedly connected to the input of or formed integrally with the helical gearing. The output of the helical gearing is connected to or formed integrally with the adjusting element. An anti-twist means may prevent the adjusting element from twisting in the circumferential direction about the axis. The helical gearing and/or at least part of the adjusting element is/are formed to be transversely elastic to the axis of rotation, at least in one region.

A drum brake apparatus includes: a housing; a main braking part installed on one side of the housing, and driven by hydraulic pressure so as to press a shoe during main braking; and a parking braking part installed on another side of the housing, and driven by an electromotive force of an actuator so as to press the shoe during parking braking. The housing includes: a housing part; a piston housing part formed on the housing part, having a hollow portion formed therein, and having the main braking part installed therein; and a rod housing part formed on the housing part, having a hollow portion formed therein, and having the parking braking part installed therein. The rod housing part is disposed at a location farther from a rotation center of the shoe than the piston housing part.

A hydraulic apparatus is disclosed, which includes a hydraulic cylinder body, a piston, a push assembly, and a first sealing component; the hydraulic cylinder body is of a hollow cylinder shape, provided with a first opening and a second opening respectively at two ends; the piston is disposed in the hydraulic cylinder body and is located at the first opening; the first sealing component covers the second opening; the hydraulic cylinder body, the piston, and the first sealing component are configured to form a hydraulic chamber; the hydraulic cylinder body is provided with a liquid flow opening which is located between the first sealing component and the piston; and the piston is configured to be enabled to move in the hydraulic cylinder body, driven by the push assembly.