| CPC B60T 13/385 (2013.01) [B60T 13/683 (2013.01); B60T 17/002 (2013.01); B60T 17/085 (2013.01); G05D 16/2093 (2013.01)] | 16 Claims |

|
1. An electropneumatic parking-brake valve unit for an electronically controlled pneumatic brake system of a vehicle including a utility vehicle, the electropneumatic parking-brake valve unit comprising:
at least a first supply connection for receiving supply pressure (pV) from a compressed air source;
at least one spring brake connection for connecting to at least one spring brake cylinder of the vehicle;
a parking-brake valve arrangement having at least a first bistable valve switchable between first and second switching states wherein a spring brake pressure (pF) can be controllable in dependence upon the switching state of said first bistable valve;
a pneumatically switchable holding valve having a holding-valve connection whereat a first control pressure (p1) is provided and said pneumatically switchable holding valve being connected between said first supply connection and said first bistable valve;
a deaerator;
said pneumatically switchable holding valve being pretensioned under a spring load into a first switching position wherein said first bistable valve is connected to said deaerator;
said first bistable valve being configured to switch into a second switching position when said first control pressure (p1) at said holding-valve connection exceeds a predetermined first threshold value;
wherein said first bistable valve is connected to said first supply connection to receive said supply pressure (pV) in response to being switched into said second switching position; and,
wherein said first control pressure (p1) is controlled by an electrically switchable control valve which is part of the electropneumatic parking-brake valve unit or is arranged remotely therefrom.
|