Piston pump with a piston 4 reciprocating within a pump bore 3 to draw fluid through an inlet check valve 7 into a compression chamber 5, pressurise it and discharge it through an outlet check valve 6. The piston is pushed in one direction by a camshaft rotated by a motor inside an eccentric chamber 2 around an axis orthogonal to the piston’s axis of reciprocation, and in the opposite direction by a return spring 8 inside the compression chamber. A sealing package comprising sealing rings 10.1, 10.2 and a piston sleeve is arranged around the piston, to prevent fluid flowing from the compression to the eccentric chamber. However, in the event of a leak due to wear of the sealing elements, a cavity 11 is provided in the pump bore to collect leakage fluid. The pump may be used to deliver brake fluid in vehicle brake systems. The cavity may be one or more radial bores or multiple radial fly-cuts within the piston sleeve. Alternatively, it may be a circular channel between the sealing rings, formed by recesses thereof, optionally with a further cylindrical fly-cut (12, fig. 3) and an additional bore leading to a separate reservoir (fig. 4).
Piston pump with integrated leakage
2019-12-25
Patent
Elektronische Ressource
Englisch