A valve-arrangement is operable to switch between a bistable-valve (BV) behavior and a relay-valve (RV) behavior to control a parking-brake, and includes a housing with a supply-pressure-inlet (SPI), a service brake-control-inlet (SBCI) to provide a control-pressure, a pressure-outlet, and an exhaust-port, and includes a first-piston and a second-piston both movable along a same direction in the housing to define a first-chamber communicating with the SBCI, a second-chamber between the first-piston and the second-piston, and third chamber communicating with the pressure-outlet and with a controllable connection to the SPI, in which upon the control-pressure the second-piston moves with the first-piston to connect the pressure-outlet with the exhaust-port or with the SPI. The valve arrangement includes a throttle unit adapted, depending on the control-pressure, to connect the second-chamber with the third-chamber to enable the BV behavior or disconnect the second-chamber from the third-chamber to enable the RV behavior.

A valve-arrangement is operable to switch between a bistable-valve (BV) behavior and a relay-valve (RV) behavior to control a parking-brake, and includes a housing with a supply-pressure-inlet (SPI), a service brake-control-inlet (SBCI) to provide a control-pressure, a pressure-outlet, and an exhaust-port, and includes a first-piston and a second-piston both movable along a same direction in the housing to define a first-chamber communicating with the SBCI, a second-chamber between the first-piston and the second-piston, and third chamber communicating with the pressure-outlet and with a controllable connection to the SPI, in which upon the control-pressure the second-piston moves with the first-piston to connect the pressure-outlet with the exhaust-port or with the SPI. The valve arrangement includes a throttle unit adapted, depending on the control-pressure, to connect the second-chamber with the third-chamber to enable the BV behavior or disconnect the second-chamber from the third-chamber to enable the RV behavior.

A spring brake actuator has a service brake with a service brake housing and a service brake working chamber located in the service brake housing. The service brake working chamber is confined by a diaphragm. A service brake piston movable along an actuator-longitudinal axis and abuts the diaphragm, which applies a brake force onto the service brake piston. A spring between the service brake piston and the service brake housing pushes the service brake piston against the direction of the brake force. A modulator valve unit communicates with the service brake working chamber and is configured to regulate the inlet and outlet of fluid into and out of the service brake working chamber. The modulator valve unit is integrated into the spring brake actuator and includes a controllable inlet valve communicating with the service brake working chamber and a controllable outlet valve communicating with the service brake working chamber.

A spring brake actuator has a service brake with a service brake housing and a service brake working chamber located in the service brake housing. The service brake working chamber is confined by a diaphragm. A service brake piston movable along an actuator-longitudinal axis and abuts the diaphragm, which applies a brake force onto the service brake piston. A spring between the service brake piston and the service brake housing pushes the service brake piston against the direction of the brake force. A modulator valve unit communicates with the service brake working chamber and is configured to regulate the inlet and outlet of fluid into and out of the service brake working chamber. The modulator valve unit is integrated into the spring brake actuator and includes a controllable inlet valve communicating with the service brake working chamber and a controllable outlet valve communicating with the service brake working chamber.

A spring brake actuator has a service brake with a service brake housing and a service brake working chamber located in the service brake housing. The service brake working chamber is confined by a diaphragm. A service brake piston movable along an actuator-longitudinal axis and abuts the diaphragm, which applies a brake force onto the service brake piston. A spring between the service brake piston and the service brake housing pushes the service brake piston against the direction of the brake force. A modulator valve unit communicates with the service brake working chamber and is configured to regulate the inlet and outlet of fluid into and out of the service brake working chamber. The modulator valve unit is integrated into the spring brake actuator and includes a controllable inlet valve communicating with the service brake working chamber and a controllable outlet valve communicating with the service brake working chamber.

A spring brake actuator has a service brake with a service brake housing and a service brake working chamber located in the service brake housing. The service brake working chamber is confined by a diaphragm. A service brake piston movable along an actuator-longitudinal axis and abuts the diaphragm, which applies a brake force onto the service brake piston. A spring between the service brake piston and the service brake housing pushes the service brake piston against the direction of the brake force. A modulator valve unit communicates with the service brake working chamber and is configured to regulate the inlet and outlet of fluid into and out of the service brake working chamber. The modulator valve unit is integrated into the spring brake actuator and includes a controllable inlet valve communicating with the service brake working chamber and a controllable outlet valve communicating with the service brake working chamber.

A valve-arrangement is operable to switch between a bistable-valve (BV) behavior and a relay-valve (RV) behavior to control a parking-brake, and includes a housing with a supply-pressure-inlet (SPI), a service brake-control-inlet (SBCI) to provide a control-pressure, a pressure-outlet, and an exhaust-port, and includes a first-piston and a second-piston both movable along a same direction in the housing to define a first-chamber communicating with the SBCI, a second-chamber between the first-piston and the second-piston, and third chamber communicating with the pressure-outlet and with a controllable connection to the SPI, in which upon the control-pressure the second-piston moves with the first-piston to connect the pressure-outlet with the exhaust-port or with the SPI. The valve arrangement includes a throttle unit adapted, depending on the control-pressure, to connect the second-chamber with the third-chamber to enable the BV behavior or disconnect the second-chamber from the third-chamber to enable the RV behavior.

A valve-arrangement is operable to switch between a bistable-valve (BV) behavior and a relay-valve (RV) behavior to control a parking-brake, and includes a housing with a supply-pressure-inlet (SPI), a service brake-control-inlet (SBCI) to provide a control-pressure, a pressure-outlet, and an exhaust-port, and includes a first-piston and a second-piston both movable along a same direction in the housing to define a first-chamber communicating with the SBCI, a second-chamber between the first-piston and the second-piston, and third chamber communicating with the pressure-outlet and with a controllable connection to the SPI, in which upon the control-pressure the second-piston moves with the first-piston to connect the pressure-outlet with the exhaust-port or with the SPI. The valve arrangement includes a throttle unit adapted, depending on the control-pressure, to connect the second-chamber with the third-chamber to enable the BV behavior or disconnect the second-chamber from the third-chamber to enable the RV behavior.