A relay valve (2) includes a housing having a pressure medium inlet that can be connected to a pressure medium source, at least one pressure medium outlet that can be connected to a consumer, at least one control input, and at least one ventilation (32) leading to the atmosphere. The relay valve (2) has further a relay valve piston (14), which is arranged in the housing along a relay valve piston axis (16) in a slidable manner. The relay valve (2) has a first sealing element (54) fixed to the housing, and a second sealing element (56) fixed to the relay valve piston for sealing the relay valve piston (14) with respect to the housing. An annular space (58) having a connection to the atmosphere is defined by the first sealing element (54), the second sealing element (56), the relay valve piston (14), and the housing.

An electric-parking-brake for a utility-vehicle, including: a feed-line for brake-pressure air; a discharge-line for brake-pressure air for a pneumatic-brake-device; a first-valve and a second-valve, each being switchable between a stable-state and an activated-state in response to electrical control-signals; and a valve-device which is connected between the feed-line and the discharge-line and exhibits a control-input, the valve device being switchable between a stable-state and an activated-state in response to control signals at the control-input, the feed-line being connected to the discharge-line in the activated-state, in which the first-valve in the stable-state or in the activated-state connects the control-input of the valve-device to the discharge-line, to retain a current-state of the valve-device when the brake-pressure air is applied to the discharge-line, and in the activated or stable state connects the control-input to the second-valve. Also described are an electric parking brake system, a utility vehicle, and a related method.

A relay valve is provided for a vehicle. The valve includes a parking brake piston that is displaceable in a housing and an axially displaceable cuff, a first compressed-air chamber for receiving compressed air from a control line is formed between the parking brake piston and the housing. The valve is also provided with a first spring element, which axially applies a pre-loading force to the cuff, and with a second spring element, which axially applies another pre-loading force to the parking brake piston. An axially displaceable service brake piston is arranged axially between the parking brake piston and the cuff, the service brake piston rests at least radially against the parking brake piston and radially against the housing in a sealing manner, in order to form a second compressed-air chamber.