A pressure-limiting valve has a valve housing, a piston, a pressure-limiting adjustment spring, at least one inlet and at least one outlet. The piston can assume an open position in which the inlet and the outlet are connected to each other and a closed position which separates the inlet and outlet. A first piston ring has a sealing surface and has a small pneumatic active surface relative to a second piston ring. Between the first and second piston rings the piston has a substantially truncated cone-like portion which tapers toward the first piston ring. In the closed position, the sealing surface of the first piston ring is sealingly drawn against a housing collar by a pneumatic force acting counter to the force of the pressure-limiting adjustment spring. A pneumatic passage for creating a safety valve function closable by a spring-loaded safety valve body is provided in the piston.