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1. (WO2018196991) A VARIABLE DISPLACEMENT LIQUID PUMP

Pub. No.:    WO/2018/196991    International Application No.:    PCT/EP2017/060163
Publication Date: Fri Nov 02 00:59:59 CET 2018 International Filing Date: Sat Apr 29 01:59:59 CEST 2017
IPC: F04C 2/344
F04C 14/22
F04C 14/24
F04C 15/00
Applicants: PIERBURG PUMP TECHNOLOGY GMBH
Inventors: CELATA, Bernardo
GUGLIELMO, Fabio
MALOTTI, Andrea
ROSSI, Giuseppe
Title: A VARIABLE DISPLACEMENT LIQUID PUMP
Abstract:
The disclosure refers to a variable displacement liquid pump (10) for pumping pressurized liquid, comprising a pump rotor (44) with radially slidable vanes (46) rotating in a shiftable control ring (42), a pressure control system for controlling the discharge pressure of the pressurized liquid. The control system comprises a pressure control chamber (54) for pushing the control ring (42) into high pumping volume direction, and a pressure control valve (78) controlling the pressure in the pressure control chamber (54). The pressure control valve (78) comprises a control plunger (86), which is movable between a first position and a second position, an input pressure plunger (90) being charged with an actual pressure (PA) in an input pressure chamber (88), wherein the input pressure plunger (90) is mechanically connected with the control plunger (86), and a control valve spring (92) preloading the control plunger (86) into the second position against the pressure in the input pressure chamber (88). The control system further comprises a separate damping unit (100), comprising a piston (108), which is moving in a separate damping chamber (112) and which is separating the damping chamber (112) in two chamber parts (112a, 112b), which are fluidically connected to each other by a damping channel (118; 120), wherein the piston (108) is stiffly connected to the control plunger (86).