Patent ID: 9062644
Filing Date: 2015-06-23
Classification: F02M,F16K,Y10T

Abstract:
1. A pressure limiting valve for arrangement in a return pipe of a common-rail system of an internal combustion engine, the pressure limiting valve comprising a valve housing having a housing head and a hollow cylindrical housing jacket that contains, in a valve base of the valve housing, an inlet opening and axially separated from the inlet opening at least one outlet opening, whereby an inner valve seat for a valve body is attached to the inlet opening in the valve base, and whereby an axially mobile valve piston is arranged between the valve seat and a closing spring, which produces a closing force against a pressure acting at the inlet opening, wherein the valve body is of a stepped configuration, which in a first step on a side facing the inlet opening features a first surface (A 1 ), which is acted upon in the axial direction with the pressure (p), as well as a first axial length (L 1 ), over which the valve body forms in a closed position with an outer surface of the valve body a first peripheral throttling gap with an inner surface of the valve seat, and which in a second step forms a second surface (A 2 ), which is acted upon in the axial direction (X-X) with the pressure (p), which together with the first surface (A 1 ) forms a total pressure surface (A G ), whereby in the second step a second peripheral throttling gap with a second gap width (S W ) is formed between an outer surface of the valve body and an inner surface of the housing jacket over a second axial length (L 2 ), the first peripheral throttling gap and the second peripheral throttling gap providing a hydraulic damping effect on movement of valve body during closing of the pressure limiting valve, wherein the second peripheral throttling gap formed in the second step of the valve body between the outer surface of the valve body and the inner surface of the housing jacket forms a smaller gap width (S W ) than a gap width (S d ) of the first peripheral throttling gap.