RELIEF VALVE FOR A FUEL PUMP

The invention relates to an overflow valve (10) for regulating a fuel volume flow in a low-pressure circuit of a fuel injection system and a high-pressure pump (100) having such an overflow valve (10). The overflow valve (10) has a valve housing (12) and a valve piston (14) that is displaceable in the valve housing (12), with a spring chamber (15) being formed between the valve piston (14) and the valve housing (12). A valve spring (16) is arranged in the spring chamber (15), by means of which the valve piston (14) is supported relative to the valve housing. At least one relief bore (17) is formed at the valve housing (12), which in a relieved state of the valve spring (16) is at least largely closed by the valve piston (14). The valve piston (14) has a radial bore (18) in the form of a venturi nozzle (19), comprising a first section (21) with a tapered cross-section, a second section (22) with a smallest cross-section and a third section (23) with an expanding cross-section, wherein the second section (22) is hydraulically connected to the spring chamber (15) via a channel (24).