Electropneumatic parking brake control device, and braking system of a vehicle

An electropneumatic parking brake control device for controlling a parking brake having at least one spring brake actuator, comprising:

• a) a connection for the at least one spring brake actuator,
• b) a solenoid valve device which is controllable by an electronic control device,
• c) a relay valve whose pneumatic control inlet is connected at one end to the solenoid valve device and at the other end to a working outlet and to the connection for the at least one spring brake actuator,
• d) a supply connection for at least one pressurized air supply which is connected at one end to the solenoid valve device and at the other end to a supply inlet of the relay valve,
• e) a feedback line through which the working outlet and the pneumatic control inlet of the relay valve are connected to one another, wherein
• f) the relay valve has a control chamber which is connected to the pneumatic control inlet, at least one relay piston which is controlled by the pressure in the control chamber and activates a double seat valve, and a working chamber which is connected to the working outlet, wherein the relay piston is guided within a relay valve housing and bounds the control chamber and the working chamber, and the double seat valve comprises at least one inlet seat and at least one outlet seat, wherein when the outlet seat is opened, the working chamber is connected to a vent, and when the inlet valve is opened said working chamber is connected to the supply inlet, and wherein
• g) at least one first throttle element is arranged in the feedback line in such a way that the working outlet and the pneumatic control inlet of the relay valve always have a throttled flow connection to one another, and wherein
• h) the control chamber of the relay valve is connected to the vent via at least one second throttle element exclusively when the relay piston is in a venting position or in an intermediate position, but the connection of the control chamber to the vent is interrupted by the at least one second throttle element if the relay piston is in an aeration position, wherein
• h1) the venting position of the relay piston within the relay valve housing is characterized in that the outlet seat is completely opened and the inlet seat of the double seat valve is completely closed, and as a result a pressure arises at the connection for the at least one spring brake actuator, which pressure corresponds to an application pressure of the at least one spring brake actuator, at which pressure said actuator is completely applied, and wherein
• h2) the aeration position of the relay piston within the relay valve housing is characterized in that the inlet seat is completely opened and the outlet seat is completely closed, and as a result a pressure arises at the connection for the at least one spring brake actuator, which pressure corresponds to a release pressure of the at least one spring brake actuator, at which pressure said actuator is completely released, and wherein
• h3) the intermediate position of the relay piston within the relay valve housing is characterized in that a pressure arises at the connection for the at least one spring brake actuator, which pressure is higher than the application pressure but lower than the release pressure, and further wherein
• i) the control chamber of the relay valve is connected to the vent via at least one third throttle element exclusively when the relay piston is in the venting position, but the connection between the control chamber and the vent is interrupted by the at least one third throttle element if the relay piston is in the aeration position or in the intermediate position, and wherein
• j) a flow cross-section which is made available by the at least one third throttle element is larger than a flow cross-section which is made available by the at least one first throttle element, and
• k) a flow cross-section which is made available by the at least one second throttle element is smaller than the flow cross-section which is made available by the at least one first throttle element.