초록 ▼

In the case of a pressure control device for electropneumatic brake systems of vehicles, particularly utility vehicles, an electromagnetically operable intake valve is provided between a compressed air supply and a consuming device of the brake system. The pressure of the consuming device in the for

In the case of a pressure control device for electropneumatic brake systems of vehicles, particularly utility vehicles, an electromagnetically operable intake valve is provided between a compressed air supply and a consuming device of the brake system. The pressure of the consuming device in the form of a brake cylinder is measured by a pressure sensor and transmitted for the controlled actuating of the intake valve to an electronic control unit. The intake valve is constructed as a valve piston which acts with respect to a valve seat and which, on its approach flow end situated upstream of the valve seat, acts such by means of an intake cross-section which can be changed as a function of the piston stroke, with respect to the housing receiving the valve piston. Thus, according to the values determined by the pressure sensor, a controlled feeding of compressed air is permitted corresponding to the selected contouring. The exhaust valve of the pressure control device, which exists between the consuming device and the outside air, can be contoured in a similar manner so that the piston stroke can have a cross-section-variable effect with respect to the housing.

대표청구항 ▼

[ What is claimed is:] [1.] An electropneumatic brake system comprising:a compressed air supply,a brake cylinder,a pressure relief zone,a movable intake valve including a solenoid operable to control air pressure from the compressed air supply to the brake cylinder, said intake valve having a cross-

[ What is claimed is:] [1.] An electropneumatic brake system comprising:a compressed air supply,a brake cylinder,a pressure relief zone,a movable intake valve including a solenoid operable to control air pressure from the compressed air supply to the brake cylinder, said intake valve having a cross-section which varies as a function of a position of its solenoid,a movable exhaust valve including a solenoid operable to control air exhaust from the brake cylinder to the pressure relief zone, said exhaust valve having a cross-section which varies as a function of a position of its solenoid,a pressure sensor which continuously monitors pressure acting on the brake cylinder,and an electronic control unit operable to control said solenoids as a function of pressure sensed by the pressure sensor to thereby accommodate both normal braking operation and emergency or ABS braking operation by utilizing the variable valve cross-sections controlled by positions of the solenoids,wherein at least one of said valves is provided with a valve piston cooperating with a valve seat of a valve housing, said valve piston and valve seat having contoured surfaces which extend axially and radially of an axial travel path of said piston to thereby provide a variable flow cross-section for air as a function of respective relative axial positions of said valve piston and valve seat, andwherein said contoured surfaces are respective stepped surfaces which are operable to provide a stepped change in said variable flow cross-section as a function of respective relative axial positions of said valve piston and valve seat.