Pressure control valve with integrated pressure compensation function and check valve function

A pneumatic pressure-regulating valve for a brake control system of a rail vehicle, the pneumatic pressure-regulating valve comprising:

• at least three pressure chambers admitting compressed air and formed in a housing of the pressure-regulating valve,
• wherein a first pressure chamber, sealed off by a piston and a valve seat arranged on a valve tappet, has a brake pressure admitted to it and has a fluid connection by way of a passage in the valve tappet to a second pressure chamber to relieve pressure,
• wherein a third pressure chamber to which a supply pressure is admitted is furthermore arranged between the two pressure chambers and a sealing between the third pressure chamber and the second pressure chamber is provided by a flat diaphragm arranged in the third pressure chamber and which allows an axial movement of the valve tappet,
• wherein the flat diaphragm comprises a centrally arranged circular opening for achieving a check function, wherein the valve tappet extends fully through the flat diaphragm in an axial direction, and
• wherein, in response to pressure in the second chamber being greater than a supply pressure in the third chamber, the flat diaphragm circular opening moves relative the valve tappet so that the sealing between the second pressure chamber and the third pressure chamber is lost.