In a brake actuator including a plurality of actuator housing portions, a diaphragm seal, partially delimiting a parking brake de-actuation chamber, is retained between adjacent actuator housing portions, and an elastic element disposed between the diaphragm seal and one of the housing portions opposes expansion of the parking brake de-actuation chamber. A push rod extends into and out of a service brake actuation chamber upon respective release of fluid pressure from the parking brake de-actuation chamber and supply of fluid pressure to the parking brake de-actuation chamber. In order to constrain a central portion of the diaphragm seal for movement together with both the push rod and a piston, a clamping arrangement is used to axially clamp the central diaphragm seal portion between an end of the push rod and a surface of the piston.

An air disc brake system for a heavy-duty vehicle comprising an axle. A spindle is attached to an end portion of the axle. At least a portion of an air disc brake assembly is supported by the spindle. A suspension beam has an axle support portion connectable with the axle. An end portion of the suspension beam is spaced from the axle support portion for attachment with the heavy-duty vehicle. The suspension beam may pivot about the end portion of the suspension beam. An actuator actuates the air disc brake assembly. The actuator has a movable member to actuate the air disc brake assembly. Structure is associated with the suspension beam for supporting at least a portion of the actuator. A surface defines an opening in the suspension beam through which the movable member may extend or that may receive and support a portion of the actuator.

Displacement of a piston of a power brake pressure producer of a hydraulic assembly of a hydraulic vehicle brake system by an electric motor, via a cycloidal gear and a sliding screw gear having a trapezoidal thread.

Displacement of a piston of a power brake pressure producer of a hydraulic assembly of a hydraulic vehicle brake system by an electric motor, via a cycloidal gear and a sliding screw gear having a trapezoidal thread.

A method for ascertaining an available fluid volume in a tank for brake fluid of a braking system. The braking system includes a pressure generator fluidically connected to the tank on the one hand and to at least one brake circuit on the other hand, which is activatable for generating a hydraulic pressure in the braking system as brake fluid is withdrawn from the tank. A drop below a predefined limiting value for a fill level of the brake fluid in the tank is monitored with the aid of a binary sensor assigned to the tank. It is provided that an actuation of the pressure generator is monitored and that the available fluid volume is ascertained as a function of the actuation of the pressure generator when the instantaneous fill level drops below the limiting value.

A method for ascertaining an available fluid volume in a tank for brake fluid of a braking system. The braking system includes a pressure generator fluidically connected to the tank on the one hand and to at least one brake circuit on the other hand, which is activatable for generating a hydraulic pressure in the braking system as brake fluid is withdrawn from the tank. A drop below a predefined limiting value for a fill level of the brake fluid in the tank is monitored with the aid of a binary sensor assigned to the tank. It is provided that an actuation of the pressure generator is monitored and that the available fluid volume is ascertained as a function of the actuation of the pressure generator when the instantaneous fill level drops below the limiting value.

A spring brake cylinder (100) for a brake system (800) of a motor vehicle (1000) includes a brake release mechanism (110), configured to axially contract a brake spring chamber (112) against a brake spring force in a release direction (RD) from a parking position (PP) to a driving position (PD). A brake state indicator (120) includes an actuation element (128) axially held in a force equilibrium (EF) between an actuation spring (124), exerting an actuation force (FA) on the actuation element (128), and a return spring (126), exerting a return force (FR) on the actuation element (128). The actuation force (FA) is altered by nut motion (MN) of a running nut (122), caused by rotational motion of a release screw (132) to shift the force equilibrium (FE), resulting in an axial movement (ME) of an actuation element (128) operatively coupled to an indicator pin (134) of the brake state indicator (120).

An electropneumatic parking-brake valve unit for an electronically controlled pneumatic brake system has a first supply connection to a compressed air source. A spring brake connection connects to a spring brake cylinder of a vehicle. A parking-brake valve arrangement has a bistable valve switchable between switching states wherein a spring brake pressure can be controllable in dependence upon the switching state. A pneumatically switchable holding valve has a holding-valve connection for a first control pressure and the holding valve is connected between the first supply connection and the bistable valve. The holding valve is under a spring load into a first switching position wherein the bistable valve is connected to a deaerator. The bistable valve switches into a second switching position when the first control pressure exceeds a first threshold value. The bistable valve is connected to the first supply connection.

An interface between an adapter push rod and a parking brake diaphragm seal includes an axial projection at one end of the push rod, a thread extending axially between a free end of the projection and a remainder of the push rod, and a washer having an approximately conical wall extending radially inwardly from an outer circumference of the washer towards a central mounting connection having a radial flange. A nut is threaded over the free end of the projection, and an opening in a hardened element is aligned axially with the projection to receive the projection. A circumferential groove defined in a side of the radial flange forms a boundary between the approximately conical wall and a remainder of the washer, and a portion of the diaphragm seal is pressed by the nut and the hardened element into the circumferential groove to produce a sealing bead.

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).