Patent ID: 11970146
Assignee: ZF CV SYSTEMS EUROPE BV
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 9:
10. An electronically controllable secondary brake system (46, 46′) of a vehicle (2), the secondary brake system operable as both a parking brake system and an auxiliary brake system, the secondary brake system operated by pressure medium and comprising:
spring brake cylinders (68a, 68b) arranged on wheel brakes of at least one vehicle axle (8);
a directly or indirectly electronically controllable brake control valve (56, 56′), an electronic brake control unit (48) that controls the brake control valve (56, 56′) in a manner that is dependent on the current value of a brake value signal (SBW),
wherein the brake control valve is a 3/3-way proportional valve with a pressure medium inlet, a pressure medium outlet, and a working connector,
wherein the working connector is adjustable continuously between a connection to the pressure medium outlet and to the pressure medium inlet,
wherein the pressure medium inlet is connected via a supply line (52) to a pressure medium source (14),
wherein the pressure medium outlet is connected to a pressure medium sink (16b), and
wherein the working connector is connected via a working line (60, 66) to the spring brake cylinders (68a, 68b),
wherein a controllable check valve (62), which shuts off in the direction of the brake control valve (56, 56′), is arranged in the working line (60)
wherein brake force of the spring brake cylinder (68a, 68b) is reduced by the brake control valve (56, 56′) by way of a feed of pressure medium and
wherein the brake force of the spring brake cylinder (68a, 68b) is increased by the brake control valve (56, 56′) by way of a discharge of pressure medium,
wherein the secondary brake system (46, 46′) is either configured as a hydraulic brake system or as a compressed air brake system,
wherein in the hydraulic brake system the pressure medium source (14) has: an oil pump (18), a hydraulic pressure preparation device (20), and a hydraulic pressure accumulator (54), and wherein the pressure medium sink (16, 16a, 16b, 16c, 16d) is configured as at least one hydraulic collecting vessel;
wherein in the compressed air brake system, the pressure medium source has: a compressor, a pneumatic pressure preparation device, and a pneumatic pressure accumulator, and wherein the pressure medium sink comprises at least one ventilation outlet.