Piston pump for pumping a fluid and associated brake system

Abstract

Piston pump with a piston assembly (22) having at least one transverse bore (23) and a longitudinal bore (24) corresponding to the at least one transverse bore (23), a cylinder (28) in which the piston assembly (22) is guided longitudinally, and an inlet valve (25) having a cage element (31) in which an inlet valve spring (25.2) and an inlet valve sealing element (25.3) is arranged, and comprises a corresponding inlet valve seat (25.1) which is arranged on the piston assembly (22), wherein the inlet valve sealing element (25.3) can be pressed into the corresponding inlet valve seat (25.1) by a spring force of the inlet valve spring (25.2) to seal the longitudinal bore (24), wherein fluid can be drawn in via the at least one transverse bore (23) arranged in the piston assembly (22), which can be directed through the longitudinal bore (24) via the inlet valve (25) into a compression chamber (28.1) in which a return spring (30) for the piston assembly (22) is arranged and wherein the cage element (31) has an elastic high-pressure sealing element (31.1) which has a radial bearing area (31.4) towards a cylinder wall (28.4) for receiving and centering an upper end winding (30.1) of the return spring (30), characterized in that that the return spring (30) is designed as a simple cylindrical spiral spring without ground coil ends, which is axially supported with an upper end coil (30.1) on the cage element (31) and with a lower end coil (30.2) on a cylinder base (28.2) and wherein the cylinder (28) at the transition between the cylinder wall (28.4) and the cylinder base (28.2) has a cylinder base radius (28.5) adapted to a radius of the spring wire of the lower end coil (30.2) of the return spring (30) for guiding the return spring (30), that the cylinder base radius (28.5) corresponds to a radius of the spring wire of the return spring (30), that the radial support area (31.4) is designed as a radial receiving groove, wherein the radial receiving groove is formed at the outer edge as a flexible sealing lip (31.2) which seals the compression chamber (28.1) to the cylinder wall (28.4) in a pressure-tight manner and that the elastic high-pressure sealing element (31.1) is designed to absorb radially acting force components and to seal the compression chamber (28.1) against the cylinder wall (28.4) via a radial sealing surface (31.3), wherein the radial sealing surface (31.3) can be formed by a pressure-induced expansion of the high-pressure sealing element (31.1).

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